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Applying the S&S technology platform in modern clinical genomics research hasadvance diagnosis and treatment of human diseases.
In the modern era of Next Generation Sequencing (NGS) technology, S&S is applied in clinical practice extensively. Clinicians and molecular diagnostic laboratories apply S&S using various computational tools including HSF, SSF, and Alamut. It is aiding in the discovery of genes and mutations in patients whose disease are stratified or when the disease in a patient is unknown based on clinical investigations.
In this context, S&S has been applied on cohorts of patients in different ethnic groups with various cancers and inherited disorders. A few examples are given below. | 1 | Gene expression + Signal Transduction |
Allopolyploids are species whose increased complement of genetic material is the result of hybridization of two closely related species. Thus homeologous chromosomes in allopolyploids are equivalent, but not identical. These differences mean that the precise pattern of silencing and expression can have important phenotypic effects. Reciprocal silencing on the population level refers to the case where two populations are each descended from the same allopolyploid. In one population, one of the two equivalent locci (A) is expressed while the other (B) has been silenced, while in the other population the reciprocal pattern occurs, with B being expressed and A silenced. It is important to note that this refers to equivalent loci, specific locations within the genome, rather than the entire homeologous chromosome.
Reciprocal silencing on the population level has been proposed as a means of allopatric speciation following a polyploid event. Allopatric speciation occurs when two populations of the same species become spatially separated and accumulate enough genetic differences to lose the ability to interbreed. As redundant genes are silenced in allopolyploids there is the potential for rapid genetic differences to accumulate through reciprocal silencing. These differences can lead to the loss of ability to interbreed between separated populations at a faster rate than other methods of speciation, given the relative speed with which genes are silenced following a polyploid event. Faster still, redundant genes can be silenced through epigenetic means, although the importance of this phenomenon is not fully understood. | 1 | Gene expression + Signal Transduction |
Initiation in archaea is governed by TATA-binding protein (TBP), Archaeal transcription factor B (TFB), and Archaeal transcription factor E (TFE) that are homologous to eukaryotic TBP, TFIIB, and TFIIE respectively. These factors recognize the promoter core sequence (TATA box, B recognition element) upstream of the coding region and recruits the RNAP to form a closed transcription preinitiation complex (PIC).
The PIC is turned into an open state with the local DNA helix "melting" to load the template strand of DNA. The RNAP undergoes "abortive initiation": it makes and releases many short (2-15nt) segments before generating a transcript of significant length. This continues until it moves past the promoter (promoter escape), loosening TBP's grasp on the DNA, and swapping TFE out for elongation factors Spt4/5. How this escape happens exactly remains to be studied. | 1 | Gene expression + Signal Transduction |
In plasma spraying process, the material to be deposited (feedstock)—typically as a powder, sometimes as a liquid, suspension or wire—is introduced into the plasma jet, emanating from a plasma torch. In the jet, where the temperature is on the order of 10,000 K, the material is melted and propelled towards a substrate. There, the molten droplets flatten, rapidly solidify and form a deposit. Commonly, the deposits remain adherent to the substrate as coatings; free-standing parts can also be produced by removing the substrate. There are a large number of technological parameters that influence the interaction of the particles with the plasma jet and the substrate and therefore the deposit properties. These parameters include feedstock type, plasma gas composition and flow rate, energy input, torch offset distance, substrate cooling, etc. | 0 | Metallurgy |
β-catenin destabilization by ethanol is one of two known pathways whereby alcohol exposure induces fetal alcohol syndrome (the other is ethanol-induced folate deficiency). Ethanol leads to β-catenin destabilization via a G-protein-dependent pathway, wherein activated Phospholipase Cβ hydrolyzes phosphatidylinositol-(4,5)-bisphosphate to diacylglycerol and inositol-(1,4,5)-trisphosphate. Soluble inositol-(1,4,5)-trisphosphate triggers calcium to be released from the endoplasmic reticulum. This sudden increase in cytoplasmic calcium activates Ca2+/calmodulin-dependent protein kinase (CaMKII). Activated CaMKII destabilizes β-catenin via a poorly characterized mechanism, but which likely involves β-catenin phosphorylation by CaMKII. The β-catenin transcriptional program (which is required for normal neural crest cell development) is thereby suppressed, resulting in premature neural crest cell apoptosis (cell death). | 1 | Gene expression + Signal Transduction |
If a specimen must be observed at higher magnification, it can be examined with a scanning electron microscope (SEM), or a transmission electron microscope (TEM). When equipped with an energy dispersive spectrometer (EDS), the chemical composition of the microstructural features can be determined. The ability to detect low-atomic number elements, such as carbon, oxygen, and nitrogen, depends upon the nature of the detector used. But, quantification of these elements by EDS is difficult and their minimum detectable limits are higher than when a wavelength-dispersive spectrometer (WDS) is used. But quantification of composition by EDS has improved greatly over time. The WDS system has historically had better sensitivity (ability to detect low amounts of an element) and ability to detect low-atomic weight elements, as well as better quantification of compositions, compared to EDS, but it was slower to use. Again, in recent years, the speed required to perform WDS analysis has improved substantially. Historically, EDS was used with the SEM while WDS was used with the electron microprobe analyzer (EMPA). Today, EDS and WDS is used with both the SEM and the EMPA. However, a dedicated EMPA is not as common as an SEM. | 0 | Metallurgy |
Although they are classically thought of working only together, GPCRs may signal through G-protein-independent mechanisms, and heterotrimeric G-proteins may play functional roles independent of GPCRs. GPCRs may signal independently through many proteins already mentioned for their roles in G-protein-dependent signaling such as β-arrs, GRKs, and Srcs. Such signaling has been shown to be physiologically relevant, for example, β-arrestin signaling mediated by the chemokine receptor CXCR3 was necessary for full efficacy chemotaxis of activated T cells. In addition, further scaffolding proteins involved in subcellular localization of GPCRs (e.g., PDZ-domain-containing proteins) may also act as signal transducers. Most often the effector is a member of the MAPK family. | 1 | Gene expression + Signal Transduction |
The LHCGRs become desensitized when exposed to LH for some time. A key reaction of this downregulation is the phosphorylation of the intracellular (or cytoplasmic) receptor domain by protein kinases. This process uncouples Gs protein from the LHCGR. | 1 | Gene expression + Signal Transduction |
A modern steel plant employs very few people per tonne, compared to the past. In South Korea, Posco employs 29,648 people to produce 28 million tonnes.
During the period 1974 to 1999, the steel industry had drastically reduced employment all around the world. In the US, it was down from 521,000 to 153,000. In Japan, from 459,000 to 208,000; Germany from 232,000 to 78,000; UK from 197,000 to 31,000; Brazil from 118,000 to 59,000; South Africa from 100,000 to 54,000. South Korea already had a low figure. It was only 58,000 in 1999. The steel industry had reduced its employment around the world by more than 1,500,000 in 25 years. | 0 | Metallurgy |
A variety of other compounds are added to optimize the separation process, these additives are called modifiers. Modifying reagents react either with the mineral surfaces or with collectors and other ions in the flotation pulp, resulting in a modified and controlled flotation response.
* pH modifiers include lime (used as quicklime CaO, or more commonly as slaked lime, a slurry of Ca(OH)), Soda ash (NaCO), Caustic soda (NaOH), sulfuric and hydrochloric acid (HSO, HCl).
, Ca, Cu, Pb, Zn, Ag-->
* Anionic modifiers include phosphates, silicates, and carbonates.
* Organic modifiers include the thickeners dextrin, starch, glue, and CMC. | 0 | Metallurgy |
tRNA (also tRNA-like) splicing is another rare form of splicing that usually occurs in tRNA. The splicing reaction involves a different biochemistry than the spliceosomal and self-splicing pathways.
In the yeast Saccharomyces cerevisiae, a yeast tRNA splicing endonuclease heterotetramer, composed of TSEN54, TSEN2, TSEN34, and TSEN15, cleaves pre-tRNA at two sites in the acceptor loop to form a 5-half tRNA, terminating at a 2,3-cyclic phosphodiester group, and a 3-half tRNA, terminating at a 5-hydroxyl group, along with a discarded intron. Yeast tRNA kinase then phosphorylates the 5-hydroxyl group using adenosine triphosphate. Yeast tRNA cyclic phosphodiesterase cleaves the cyclic phosphodiester group to form a 2-phosphorylated 3 end. Yeast tRNA ligase adds an adenosine monophosphate group to the 5 end of the 3-half and joins the two halves together. NAD-dependent 2-phosphotransferase then removes the 2-phosphate group. | 1 | Gene expression + Signal Transduction |
Hexaferrum and epsilon iron (ε-Fe) are synonyms for the hexagonal close-packed (HCP) phase of iron that is stable only at extremely high pressure.
A 1964 study at the University of Rochester mixed 99.8% pure α-iron powder with sodium chloride, and pressed a 0.5-mm diameter pellet between the flat faces of two diamond anvils. The deformation of the NaCl lattice, as measured by x-ray diffraction (XRD), served as a pressure indicator. At a pressure of 13 GPa and room temperature, the body-centered cubic (BCC) ferrite powder transformed to the HCP phase in Figure 1. When the pressure was lowered, ε-Fe transformed back to ferrite (α-Fe) rapidly. A specific volume change of −0.20 cm/mole ± 0.03 was measured. Hexaferrum, much like austenite, is more dense than ferrite at the phase boundary. A shock wave experiment confirmed the diamond anvil results. Epsilon was chosen for the new phase to correspond with the HCP form of cobalt.
The triple point between the alpha, gamma and epsilon phases in the unary phase diagram of iron has been calculated as T = 770 K and P = 11 GPa, although it was determined at a lower temperature of T = 750 K (477 °C) in Figure 1. The Pearson symbol for hexaferrum is hP2 and its space group is P6/mmc.
Another study concerning the ferrite-hexaferrum transformation metallographically determined that it is a martensitic rather than equilibrium transformation.
While hexaferrum is purely academic in metallurgical engineering, it may have significance in geology. The pressure and temperature of Earths iron core are on the order of 150–350 GPa and 3000 ± 1000 °C. An extrapolation of the austenite-hexaferrum phase boundary in Figure 1 suggests hexaferrum could be stable or metastable in Earths core. For this reason, many experimental studies have investigated the properties of HCP iron under extreme pressures and temperatures. Figure 2 shows the compressional behaviour of ε-iron at room temperature up to a pressure as would be encountered halfway through the outer core of the Earth; there are no points at pressures lower than approximately 6 GPa, because this allotrope is not thermodynamically stable at low pressures but will slowly transform into α-iron. | 0 | Metallurgy |
In both prokaryotes and eukaryotes signal sequences may act co-translationally or post-translationally.
The co-translational pathway is initiated when the signal peptide emerges from the ribosome and is recognized by the signal-recognition particle (SRP). SRP then halts further translation (translational arrest only occurs in Eukaryotes) and directs the signal sequence-ribosome-mRNA complex to the SRP receptor, which is present on the surface of either the plasma membrane (in prokaryotes) or the ER (in eukaryotes). Once membrane-targeting is completed, the signal sequence is inserted into the translocon. Ribosomes are then physically docked onto the cytoplasmic face of the translocon and protein synthesis resumes.
The post-translational pathway is initiated after protein synthesis is completed. In prokaryotes, the signal sequence of post-translational substrates is recognized by the SecB chaperone protein that transfers the protein to the SecA ATPase, which in turn pumps the protein through the translocon. Although post-translational translocation is known to occur in eukaryotes, it is poorly understood. It is known that in yeast post-translational translocation requires the translocon and two additional membrane-bound proteins, Sec62 and Sec63. | 1 | Gene expression + Signal Transduction |
In 1866, the government of the Russian Empire concluded an agreement with Prince Sergey Victorovich Kochubey, according to which the prince undertook to build a plant for the manufacture of iron rails in the south of the Russian Empire. In 1869, Kochubey sold the enterprise to John Hughes for £24,000.
In 1869, Hughes (or Yuz) began the construction of a metallurgical plant with a working settlement near the village of Aleksandrovka.
On April 24, 1871, the first blast furnace was built and on January 24, 1872, the plant of the Novorossiysk Society for Coal, Iron and Rail Production produced the first pig iron.
In the "Mining Journal" for 1889, the oldest plan of the NRO plant was published. In addition to the location of industrial facilities, this plan also shows the first, one-story house of John Hughes, built by the Hughes family in 1874. Now this place is located on the territory of a metallurgical plant, near the administrative building of the electric steel smelting and swaging shops, next to the monument "In honor of the smelting of the 100 millionth ton of steel on December 24, 1967."
In 1901, a social-democratic circle was created at the plant. The factory workers took an active part in the First Russian Revolution of 1905.
The plant worked as a full metallurgical cycle. For the first time in the Russian Empire 8 coke ovens are launched. Hot blast is mastered. The plant became one of the industrial centers of the Russian Empire.
In 1908–1913, 1916–1917, the outstanding metallurgist Mikhail Konstantinovich Kurako worked at the plant.
In 1917, 25 thousand people worked at the plant, mines, and mines of the society.
On March 5 (18), 1917, the Council of Workers Deputies was created in Yuzovka, which included factory workers, after which an 8-hour working day was established at the enterprise . In the autumn of 1917, workers control was established at the enterprise, attempts by the plant administration to stop the enterprise were suppressed, coal mining and production continued. A detachment of factory workers was sent to fight Kaledin. The workers of the plant later on took an active part in the establishment of Soviet power in the Donbas. | 0 | Metallurgy |
A conjoined gene (CG) is defined as a gene, which gives rise to transcripts by combining at least part of one exon from each of two or more distinct known (parent) genes which lie on the same chromosome, are in the same orientation, and often (95%) translate independently into different proteins. In some cases, the transcripts formed by CGs are translated to form chimeric or completely novel proteins.
Several alternative names are used to address conjoined genes, including combined gene and complex gene, fusion gene, fusion protein, read-through transcript, co-transcribed genes, bridged genes, spanning genes, hybrid genes, locus-spanning transcripts, etc.
At present, 800 CGs have been identified in the entire human genome by different research groups across the world including Prakash et al., Akiva et al., Parra et al., Kim et al., and in the 1% of the human genome in the ENCODE pilot project. 36% of all these CGs could be validated experimentally using RT-PCR and sequencing techniques. However, only a very limited number of these CGs are found in the public human genome resources such as the Entrez Gene database, the UCSC Genome Browser and the Vertebrate Genome Annotation (Vega) database. More than 70% of the human conjoined genes are found to be conserved across other vertebrate genomes with higher order vertebrates showing more conservation, including the closest human ancestor, chimpanzee. Formation of CGs is not only limited to the human genome but some CGs have also been identified in other eukaryotic genomes, including mouse and drosophila. There are a few web resources which include information about some CGs in addition to the other fusion genes, for example, ChimerDB and [http://www.primate.or.kr/hybriddb HYBRIDdb]. Another database, [http://metasystems.riken.jp/conjoing/ ConjoinG], is a comprehensive resource dedicated only to the 800 Conjoined Genes identified in the entire human genome. | 1 | Gene expression + Signal Transduction |
Ankyrin repeat and kinase domain containing 1 (ANKK1) also known as protein kinase PKK2 or sugen kinase 288 (SgK288) is an enzyme that in humans is encoded by the ANKK1 gene. The ANKK1 is a member of an extensive family of the Ser/Thr protein kinase family, and protein kinase superfamily involved in signal transduction pathways. | 1 | Gene expression + Signal Transduction |
* Advantages
** At large, protocells are advantageous because they can store more drugs, be loaded faster than other nanomedicine delivery systems, and are more stable than liposomes. By keeping more drugs, researchers can reduce the quantity of medications needed to be administered, potentially reducing side effects and toxicity. In like manner, controlling the direction and movement of a drug also reduces the amount of medication needed, increases the speed of delivery, and allows for the controlled release of high-concentration multicomponent cargo within cancer cells. Finally, the stability of protocells is vital because it ensures that the drugs remain effective and do not degrade before reaching their target. Overall, the development of protocells as a drug delivery system, coupled with chemotactic properties, holds great promise for targeted drug delivery.
* Limitations
** One fundamental limitation of protocells is their modularity and versatility, which must be accounted for when assessing clinical applications. Modularity and versatility are essential considerations for targeted drug delivery because they enable the customization and adaptation of drug delivery systems to meet specific clinical needs. In fact, without modularity and versatility, it will be hard to tailor protocells to different therapeutic applications and particular populations. Another critical challenge, especially when using enzymes to maneuver the protocell, is that the motility reduces when the enzymes become oversaturated with the chemical stimuli. Reducing motility becomes a problem because this is essential for targeted drug delivery efficiency, limiting the system's effectiveness and increasing the risk of off-target effects. Therefore, further research is still needed to improve our understanding of protocells and their potential clinical applications. | 1 | Gene expression + Signal Transduction |
UPt forms crystals of hexagonal symmetry (some studies hypothesize a trigonal structure instead), space group P6/mmc, cell parameters a = 0.5766 nm and c = 0.4898 nm (c should be understood as distance from planes), with a structure similar to nisnite (NiSn) and MgCd.
The compound congruently melts at 1700 °C. The enthalpy of formation of the compound is -111 kJ/mol.
At temperatures below 1 K it becomes superconducting, thought to be due to the presence of heavy fermions (the uranium atoms). | 0 | Metallurgy |
The first models which tried to explain the clustering of genes were, of course, focused on operons because they were discovered before eukaryote gene clusters were. In 1999 Lawrence proposed a model for the origin operons. This selfish operon model suggests that individual genes were grouped together by vertical en horizontal transfer and were preserved as a single unit because that was beneficial for the genes, not per se for the organism. This model predicts that the gene clusters must have conserved between species. This is not the case for many operons and gene clusters seen in eukaryotes.
According to Eichler and Sankoff the two mean processes in eukaryotic chromosome evolution are 1) rearrangements of chromosomal segments and 2) localized duplication of genes. Clustering could be explained by reasoning that all genes in a cluster are originated from tandem duplicates of a common ancestor. If all co-expressed genes in a cluster were evolved from a common ancestral gene it would have been expected that theyre co-expressed because they all have comparable promoters. However, gene clustering is a very common tread in genomes and it isnt clear how this duplication model could explain all of the clustering. Furthermore, many genes that are present in clusters are not homologous.
How did evolutionary non-related genes come in close proximity in the first place? Either there is a force that brings functionally related genes near to each other, or the genes came near by change. Singer et al. proposed that genes came in close proximity by random recombination of genome segments. When functionally related genes came in close proximity to each other, this proximity was conserved. They determined all possible recombination sites between genes of human and mouse. After that, they compared the clustering of the mouse and human genome and looked if recombination had occurred at the potentially recombination sites. It turned out that recombination between genes of the same cluster was very rare. So, as soon as a functional cluster is formed recombination is suppressed by the cell. On sex chromosomes, the amount of clusters is very low in both human and mouse. The authors reasoned this was due to the low rate of chromosomal rearrangements of sex chromosomes.
Open chromatin regions are active regions. It is more likely that genes will be transferred to these regions. Genes from organelle and virus genome are inserted more often in these regions. In this way non-homologous genes can be pressed together in a small domain.
It is possible that some regions in the genome are better suited for important genes. It is important for the cell that genes that are responsible for basal functions are protected from recombination. It has been observed in yeast and worms that essential genes tend to cluster in regions with a small replication rate.
It is possible that genes came in close proximity by change. Other models have been proposed but none of them can explain all observed phenomena. It's clear that as soon as clusters are formed they are conserved by natural selection. However, a precise model of how genes came in close proximity is still lacking.
The bulk of the present clusters must have formed relatively recent because only seven clusters of functionally related genes are conserved between phyla. Some of these differences can be explained by the fact that gene expression is very differently regulated by different phyla. For example, in vertebrates and plants DNA methylation is used, whereas it is absent in yeast and flies. | 1 | Gene expression + Signal Transduction |
The crystal structure of green rust can be understood as the result of inserting the foreign anions and water molecules between brucite-like layers of iron(II) hydroxide, (). The latter has an hexagonal structure, with layer sequence AcBAcB... , where A and B are planes of hydroxide ions, and c those of (iron(II), ferrous) cations. In the green rust, some cations get oxidized to (iron(III), ferric). Each triple layer AcB, which is electrically neutral in the hydroxide, becomes positively charged. The anions then intercalate between those triple layers and restore neutrality.
There are two basic structures of green rust, "type 1" and "type 2". Type 1 is exemplified by the chloride and carbonate varieties. It has a rhombohedral crystal structure similar to that of pyroaurite. The layers are stacked in the sequence AcBiBaCjCbAkA ...; where A, B, and C represent planes, a, b, and c are layers of mixed and cations, and i, j, and k are layers of the intercalated anions and water molecules. The c crystallographic parameter is 22.5–22.8 Å for the carbonate, and about 24 Å for the chloride.
Type 2 green rust is exemplified by the sulfate variety. It has a hexagonal crystal structure, with layers probably stacked in the sequence AcBiAbCjA... | 0 | Metallurgy |
The EPS process produces scale-free steel strip which is interchangeable with acid-pickled steel strip, yet the EPS process entails lower capital and operating (variable) cost than an acid-pickling line of equivalent output. For this reason the EPS process is considered to be a direct replacement of acid pickling.
In addition, the EPS process is considered less damaging to the environment than acid pickling for these reasons:
* Lower energy consumption;
* No hazardous/acidic substances used in the process;
* No potential exposure to acid fumes for people, equipment or buildings;
* No hazardous or polluting outputs or byproducts of the process with disposal or fume stack liabilities. | 0 | Metallurgy |
* Trypanosoma: UUA, UUG, CUG ;
* Leishmania: AUU, AUA ;
* Tetrahymena: AUU, AUA, AUG ;
* Paramecium: AUU, AUA, AUG, AUC, GUG, GUA(?).
(Pritchard et al., 1990) | 1 | Gene expression + Signal Transduction |
Cold water pitting of copper tube occurs in only a minority of installations. Copper water tubes are usually guaranteed by the manufacturer against manufacturing defects for a period of 50 years. The vast majority of copper systems far exceed this time period but a small minority may fail after a comparatively short time.
The majority of failures seen are the result of poor installation or operation of the water system. The most common failure seen in the last 20 years is pitting corrosion in cold water tubes, also known as Type 1 pitting. These failures are usually the result of poor commissioning practice although a significant number are initiated by flux left in the bore after assembly of soldered joints. Prior to about 1970 the most common cause of Type 1 pitting was carbon films left in the bore by the manufacturing process.
Research and manufacturing improvements in the 1960s virtually eliminated carbon as a cause of pitting with the introduction of a clause in the 1971 edition of BS 2871 requiring tube bores to be free of deleterious films. Despite this, carbon is still regularly blamed for tube failures without proper investigation. | 0 | Metallurgy |
The carboxy-terminal domain is also the binding site for spliceosome factors that are part of RNA splicing. These allow for the splicing and removal of introns (in the form of a lariat structure) during RNA transcription. | 1 | Gene expression + Signal Transduction |
Long noncoding RNAs (lncRNAs) are large transcripts (more than 200 nucleotides long) that have similar mechanism of synthesis as that of mRNAs but unlike mRNAs, lncRNAs are not translated to a protein. lncRNA contains interactor elements and structural elements. Interactor elements directly interact with other nucleic acids or proteins while the structural elements indicate the ability of some lncRNAs to form secondary and/or tertiary structures. This ability of the lncRNAs to interact with nucleic acids using its interactor elements and its ability to interact with protein using its secondary structures allows it to function in a more diverse manner than other ncRNAs such as miRNA (microRNA). LncRNA has been established to play a role in gene regulation by influencing the ability of specific regions of the gene to bind to transcriptional elements and different epigenetic modifications. One such example can be seen in the case X inactive specific transcript (XIST). In humans, 46,XX females carry an extra X chromosome (155Mb of DNA) compared to 46,XY males. To overcome this dosage imbalance, one X chromosome is randomly inactivated in human females at around the 2-8 cell stage of embryo development. This inactivation is very stable across cell divisions due to epigenetic contributions both during the initial silencing and the subsequent maintenance of the inactive X chromosome (Xi). This inactivation is carried by the lncRNA, XIST. XIST is produced in cis and inactivates the X-chromosome that it has been generated from. The inactive X chromosome can be observed as a condensed heterochromatin structure called “Barr Body”.
A study in 2013 utilized this ability of XIST as a potential therapeutic approach for treatment of trisomy 21. Trisomy 21 is commonly known as down syndrome and is caused due to presence of an additional copy of chromosome 21. The study was one of its kind as no other studies have been able to incorporate the XIST gene into a chromosome due to its large size. The study incorporated the XIST into one of the chromosomes 21 in the cells gathered from patients with down syndrome. The study was able to observe the inactivation of one of chromosome 21 in the form of a condensed heterochromatin and labeled it as a chromosome 21 barr body. Such experiments have shown to work in cells in the lab setting although no lncRNA based therapeutics are in clinical trials. The implications of such work can bring trisomy 21 and other chromosomal disorders in the realm of consideration for future gene therapy research. | 1 | Gene expression + Signal Transduction |
Neurotransmitters are tiny signal molecules stored in membrane-enclosed synaptic vesicles and released via exocytosis. Indeed, a change in electrical potential in the presynaptic cell triggers the release of these molecules. By attaching to transmitter-gated ion channels, the neurotransmitter causes an electrical alteration in the postsynaptic cell and rapidly diffuses across the synaptic cleft. Once released, the neurotransmitter is swiftly eliminated, either by being absorbed by the nerve terminal that produced it, taken up by nearby glial cells, or broken down by specific enzymes in the synaptic cleft. Numerous Na+-dependent neurotransmitter carrier proteins recycle the neurotransmitters and enable the cells to maintain rapid rates of release.
At chemical synapses, transmitter-gated ion channels play a vital role in rapidly converting extracellular chemical impulses into electrical signals. These channels are located in the postsynaptic cells plasma membrane at the synapse region, and they temporarily open in response to neurotransmitter molecule binding, causing a momentary alteration in the membranes permeability. Additionally, transmitter-gated channels are comparatively less sensitive to the membrane potential than voltage-gated channels, which is why they are unable to generate self-amplifying excitement on their own. However, they result in graded variations in membrane potential due to local permeability, influenced by the amount and duration of neurotransmitter released at the synapse.
Recently, mechanical tension, a phenomenon never thought relevant to synapse function has been found to be required for those on hippocampal neurons to fire. | 1 | Gene expression + Signal Transduction |
As mentioned before, N-acyl-homoserine lactones (AHL) are the quorum sensing signaling molecules of the gram-negative bacteria. However, these molecules may have different functional groups on their acyl chain, and also a different length of acyl chain. Therefore, there exist many different AHL signaling molecules, for example, 3-oxododecanoyl-L-homoserine lactone (3OC12-HSL) or 3-hydroxydodecanoyl-L-homoserine lactone (3OHC12-HSL). The modification of those quorum sensing (QS) signaling molecules is another sort of quorum quenching. This can be carried out by an oxidoreductase activity. As an example, we will discuss the interaction between a host, Hydra vulgaris, and the main colonizer of its epithelial cell surfaces, Curvibacter spp. Those bacteria produce 3-oxo-HSL quorum sensing molecules. However, the oxidoreductase activity of the polyp Hydra is able to modify the 3-oxo-HSL into their 3-hydroxy-HSL counterparts. We can characterize this as quorum quenching since there is an interference with quorum sensing molecules. In this case, the outcomes differ from simple QS inactivation: the host modification results in a phenotypic switch of Curvibacter, which modifies its ability to colonize the epithelial cell surfaces of H. vulgaris. | 1 | Gene expression + Signal Transduction |
In the ovary, the FSH receptor is necessary for follicular development and expressed on the granulosa cells.
In the male, the FSH receptor has been identified on the Sertoli cells that are critical for spermatogenesis.
The FSHR is expressed during the luteal phase in the secretory endometrium of the uterus.
FSH receptor is selectively expressed on the surface of the blood vessels of a wide range of carcinogenic tumors. | 1 | Gene expression + Signal Transduction |
Tell Hammeh () is a relatively small tell in the central Jordan Valley, Hashemite Kingdom of Jordan, located where the Zarqa River valley opens into the Jordan Valley.
It is the site of the earliest bloomery smelting of iron, from around 930 BC.
It is close to several of the larger tells in this part of the Jordan Valley (e.g. Tell Deir Alla, Tell al-Saidiyeh) as well as to the natural resources desirable in metal production: access to water, outcrops of marly clays (see Veldhuijzen 2005b, 297), and above all the only iron ore deposit of the wider region at Mugharet al-Warda. | 0 | Metallurgy |
U12 Intron Database (U12DB) is a biological database of containing the sequence of eukaryotic introns that are spliced out by a specialised minor spliceosome that contains U12 minor spliceosomal RNA in place of U2 spliceosomal RNA. These U12-dependent introns are under-represented in genome annotations because they often have non canonical splice sites. Release 1 of the database contains 6,397 known and predicted U12-dependent introns across 20 species. | 1 | Gene expression + Signal Transduction |
The oldest known blast furnaces in the West were built in Durstel in Switzerland, the Märkische Sauerland in Germany, and at Lapphyttan in Sweden, where the complex was active between 1205 and 1300. At Noraskog in the Swedish parish of Järnboås, traces of even earlier blast furnaces have been found, possibly from around 1100. These early blast furnaces, like the Chinese examples, were very inefficient compared to those used today. The iron from the Lapphyttan complex was used to produce balls of wrought iron known as osmonds, and these were traded internationally – a possible reference occurs in a treaty with Novgorod from 1203 and several certain references in accounts of English customs from the 1250s and 1320s. Other furnaces of the 13th to 15th centuries have been identified in Westphalia.
The technology required for blast furnaces may have either been transferred from China, or may have been an indigenous innovation. Al-Qazvini in the 13th century and other travellers subsequently noted an iron industry in the Alburz Mountains to the south of the Caspian Sea. This is close to the silk route, so that the use of technology derived from China is conceivable. Much later descriptions record blast furnaces about three metres high. As the Varangian Rus' people from Scandinavia traded with the Caspian (using their Volga trade route), it is possible that the technology reached Sweden by this means. The Vikings are known to have used double bellows, which greatly increases the volumetric flow of the blast.
The Caspian region may also have been the source for the design of the furnace at Ferriere, described by Filarete, involving a water-powered bellows at Semogo in Valdidentro in northern Italy in 1226. In a two-stage process the molten iron was tapped twice a day into water, thereby granulating it. | 0 | Metallurgy |
Bases: adenine (A), cytosine (C), guanine (G) and thymine (T) or uracil (U).
Amino acids: Alanine (Ala, A), Arginine (Arg, R), Asparagine (Asn, N), Aspartic acid (Asp, D), Cysteine (Cys, C), Glutamic acid (Glu, E), Glutamine (Gln, Q), Glycine (Gly, G), Histidine (His, H), Isoleucine (Ile, I), Leucine (Leu, L), Lysine (Lys, K), Methionine (Met, M), Phenylalanine (Phe, F), Proline (Pro, P), Serine (Ser, S), Threonine (Thr, T), Tryptophan (Trp, W), Tyrosine (Tyr, Y), Valine (Val, V) | 1 | Gene expression + Signal Transduction |
Molten Oxide Electrolysis in steelmaking is utilizing electrons as the reducing agent instead of coke as in conventional blast furnace. For steel production, this method uses an inert anode (Carbon, Platinum, Iridium or Chromium-based alloy) and places iron ore in the cathode. The electrochemical reaction in this Molten Oxide cell can reach up to 1600 °C, a temperature that melts iron ore and electrolyte oxide. Then the molten iron ore decompose following this reaction.
The electrolysis reaction will produce molten pure iron as a main product and oxygen as its by-product. Because this process does not add coke in the process, no CO gas is produced. So no direct greenhouse gas emission. Moreover, if the electricity to run such cells comes from renewable sources, this process may have zero emissions. This technology also can be implemented for producing Nickel, Chromium, and Ferrochromium.
Currently Massachusetts-based Boston Metal company is in a process to scale up this technology to an industrial level. | 0 | Metallurgy |
Research based on the split gene theory sheds light on other basic questions of exons and introns. The exons of eukaryotes are generally short (human exons average ~120 bases, and can be as short as 10 bases) and introns are usually long (average of ~3,000 bases, and can be several hundred thousands bases long), for example genes RBFOX1, CNTNAP2, PTPRD and DLG2. Senapathy provided a plausible answer to these questions, the only explanation to date. If eukaryotic genes originated from random DNA sequences, they have to match the lengths of ORFs from random sequences, and possibly should be around 100 bases (close to the median length of ORFs in random sequence). The genome sequences of living organisms exhibit exactly the same average lengths of 120 bases for exons, and the longest exons of 600 bases (with few exceptions), which is the same length as that of the longest random ORFs.
If split genes originated in random DNA sequences, then introns would be long for several reasons. The stop codons occur in clusters leading to numerous consecutive short ORFs: longer ORFs that could be defined as exons would be rarer. Furthermore, the best of the coding sequence parameters for functional proteins would be chosen from the long ORFs in random sequence, which may occur rarely. In addition, the combination of donor and acceptor splice junction sequences within short lengths of coding sequence segments that would define exon boundaries would occur rarely in a random sequence. These combined reasons would make introns long compared to exons. | 1 | Gene expression + Signal Transduction |
TADs have been reported to be relatively constant between different cell types (in stem cells and blood cells, for example), and even between species in specific cases. | 1 | Gene expression + Signal Transduction |
The generally recognized first successful commercial flotation process for mineral sulphides was invented by Frank Elmore who worked on the development with his brother, Stanley. The Glasdir copper mine at Llanelltyd, near Dolgellau in North Wales was bought in 1896 by the Elmore brothers in conjunction with their father, William. In 1897, the Elmore brothers installed the worlds first industrial-size commercial flotation process for mineral beneficiation at the Glasdir mine. The process was not froth flotation but used oil to agglomerate (make balls of) pulverised sulphides and buoy them to the surface, and was patented in 1898 (revised 1901). The operation and process was described in the April 25, 1900 Transactions of the Institution of Mining and Metallurgy of England, which was reprinted with comment, June 23, 1900, in the Engineering and Mining Journal', New York City. By this time they had recognized the importance of air bubbles in assisting the oil to carry away the mineral particles. As modifications were made to improve the process, it became a success with base metal ores from Norway to Australia.
The Elmores had formed a company known as the Ore Concentration Syndicate Ltd to promote the commercial use of the process worldwide. In 1900, Charles Butters of Berkeley, California, acquired American rights to the Elmore process after seeing a demonstration at Llanelltyd, Wales. Butters, an expert on the cyanide process, built an Elmore process plant in the basement of the Dooley Building, Salt Lake City, and tested the oil process on gold ores throughout the region and tested the tailings of the Mammoth gold mill, Tintic district, Utah, but without success. Because of Butters' reputation and the news of his failure, as well as the unsuccessful attempt at the LeRoi gold mine at Rossland, B. C., the Elmore process was all but ignored in North America.
Developments elsewhere, particularly in Broken Hill, Australia by Minerals Separation, Limited, led to decades of hard-fought legal battles and litigations for the Elmores who, ultimately, lost as the Elmore process was superseded by more advanced techniques. Another flotation process was independently invented in 1901 in Australia by Charles Vincent Potter and by Guillaume Daniel Delprat around the same time.
Potter was a brewer of beer, as well as a chemist, and was likely inspired by the way beer froth lifted up sediment in the beer. This process did not use oil, but relied upon flotation by the generation of gas formed by the introduction of acid into the pulp. In 1903, Potter sued Delprat, then general manager of BHP, for patent infringement. He lost the case for reasons of utility, with Delpat arguing that while Delprats process, which used sulphuric acid to generate the bubbles in the process, was not as useful as Delprats process, which used salt cake. Despite this, after the case was over BHP began using sulphuric acid for its flotation process.
In 1902, Froment combined oil and gaseous flotation using a modification of the Potter-Delprat process. During the first decade of the twentieth century, Broken Hill became the center of innovation leading to the perfection of the froth flotation process by many technologists there borrowing from each other and building on these first successes.
Yet another process was developed in 1902 by Arthur C. Cattermole, who emulsified the pulp with a small quantity of oil, subjected it to violent agitation, and then slow stirring which coagulated the target minerals into nodules which were separated from the pulp by gravity. The Minerals Separation Ltd., formed in Britain in 1903 to acquire the Cattermole patent, found that it proved unsuccessful. Metallurgists on the staff continued to test and combine other discoveries to patent in 1905 their process, called the Sulman-Picard-Ballot process after company officers and patentees. The process proved successful at their Central Block plant, Broken Hill that year. Significant in their "agitation froth flotation" process was the use of less than 1% oil and an agitation step that created small bubbles, which provided more surface to capture the metal and float into a froth at the surface. Useful work was done by Leslie Bradford at Port Pirie and by William Piper, Sir Herbert Gepp and Auguste de Bavay.
Mineral Separation also bought other patents to consolidate ownership of any potential conflicting rights to the flotation process - except for the Elmore patents. In 1910, when the Zinc Corporation replaced its Elmore process with the Minerals Separation (Sulman-Picard-Ballot) froth flotation process at its Broken Hill plant, the primacy of the Minerals Separation over other process contenders was assured. Henry Livingston Sulman was later recognized by his peers in his election as President of the (British) Institution of Mining and Metallurgy, which also awarded him its gold medal. | 0 | Metallurgy |
Two types of sulfate-induced hot corrosion are generally distinguished: Type I takes place above the melting point of sodium sulfate, whereas Type II occurs below the melting point of sodium sulfate but in the presence of small amounts of SO.
In Type I, the protective oxide scale is dissolved by the molten salt. Sulfur is released from the salt and diffuses into the metal substrate, forming grey- or blue-colored aluminum or chromium sulfides. With the aluminum or chromium sequestered, after the salt layer has been removed, the steel cannot rebuild a new protective oxide layer. Alkali sulfates are formed from sulfur trioxide and sodium-containing compounds. As the formation of vanadates is preferred, sulfates are formed only if the amount of alkali metals is higher than the corresponding amount of vanadium.
The same kind of attack has been observed for potassium sulfate and magnesium sulfate. | 0 | Metallurgy |
Calmodulin mediates many crucial processes such as inflammation, metabolism, apoptosis, smooth muscle contraction, intracellular movement, short-term and long-term memory, and the immune response. Calcium participates in an intracellular signaling system by acting as a diffusible second messenger to the initial stimuli. It does this by binding various targets in the cell including a large number of enzymes, ion channels, aquaporins and other proteins. Calmodulin is expressed in many cell types and can have different subcellular locations, including the cytoplasm, within organelles, or associated with the plasma or organelle membranes, but it is always found intracellularly. Many of the proteins that calmodulin binds are unable to bind calcium themselves, and use calmodulin as a calcium sensor and signal transducer. Calmodulin can also make use of the calcium stores in the endoplasmic reticulum, and the sarcoplasmic reticulum. Calmodulin can undergo post-translational modifications, such as phosphorylation, acetylation, methylation and proteolytic cleavage, each of which has potential to modulate its actions. | 1 | Gene expression + Signal Transduction |
This period was one of rapid growth for the Jameson Cells in the existing applications. Seventy-seven Cells were installed in concentrators around the world, mainly in coal and base metal operations. However, during this time, the Cell also moved into the Canadian oil sands industry for the flotation of bitumen. | 0 | Metallurgy |
In 1986, convincing evidence was provided that selenocysteine (Sec) was incorporated co-translationally. Moreover, the codon partially directing its incorporation in the polypeptide chain was identified as UGA also known as the opal termination codon. Different mechanisms for overriding the termination function of this codon have been identified in prokaryotes and in eukaryotes. A particular difference between these kingdoms is that cis elements seem restricted to the neighborhood of the UAG codon in prokaryotes while in eukaryotes this restriction is not present. Instead such locations seem disfavored albeit not prohibited.
In 2003, a landmark paper described the identification of all known selenoproteins in humans: 25 in total. Similar analyses have been run for other organisms.
The UAG codon can translate into pyrrolysine (Pyl) in a similar manner. | 1 | Gene expression + Signal Transduction |
Bioleaching is in general simpler and, therefore, cheaper to operate and maintain than traditional processes, since fewer specialists are needed to operate complex chemical plants. And low concentrations are not a problem for bacteria because they simply ignore the waste that surrounds the metals, attaining extraction yields of over 90% in some cases. These microorganisms actually gain energy by breaking down minerals into their constituent elements. The company simply collects the ions out of the solution after the bacteria have finished.
Bioleaching can be used to extract metals from low concentration ores such as gold that are too poor for other technologies. It can be used to partially replace the extensive crushing and grinding that translates to prohibitive cost and energy consumption in a conventional process. Because the lower cost of bacterial leaching outweighs the time it takes to extract the metal.
High concentration ores, such as copper, are more economical to smelt rather bioleach due to the slow speed of the bacterial leaching process compared to smelting. The slow speed of bioleaching introduces a significant delay in cash flow for new mines. Nonetheless, at the largest copper mine of the world, Escondida in Chile the process seems to be favorable.
Economically it is also very expensive and many companies once started can not keep up with the demand and end up in debt. | 0 | Metallurgy |
Ladles can be "lip pour" design, "teapot spout" design, "lip-axis design" or "bottom pour" design:
*For lip pour design the ladle is tilted and the molten metal pours out of the ladle like water from a pitcher.
*The teapot spout design, like a teapot, takes liquid from the base of the ladle and pours it out via a lip-pour spout. Any impurities in the molten metal will form on the top of the metal so by taking the metal from the base of the ladle, the impurities are not poured into the mould. The same idea is behind the bottom pour process.
*Lip-axis ladles have the pivot point of the vessel as close to the tip of the pouring spout as can be practicable. Therefore as the ladle is rotated the actual pouring point has very little movement. Lip-axis pouring is often used on molten metal pouring systems where there is a need to automate the process as much as possible and the operator controls the pouring operation at a remote distance.
*For bottom pour ladles, a stopper rod is inserted into a tapping hole in the bottom of the ladle. To pour metal the stopper is raised vertically to allow the metal to flow out the bottom of the ladle. To stop pouring the stopper rod is inserted back into the drain hole. Large ladles in the steelmaking industry may use slide gates below the taphole.
Ladles can be either open-topped or covered. Covered ladles have a (sometimes removable) dome-shaped lid to contain radiant heat; they lose heat slower than open-topped ladles. Small ladles do not commonly have covers, although a ceramic blanket may be used instead (where available).
Medium and large ladles which are suspended from a crane have a bail which holds the ladle on shafts, called trunnions. To tilt the ladle a gearbox is used and this is typically a worm gear. The gear mechanism may be hand operated with a large wheel or may be operated by an electric motor or pneumatic motor. Powered rotation allows the ladle operator to be moved to a safe distance and control the rotation of the ladle via a pendant or radio remote control. Powered rotation also allows the ladle to have a number of rotation speeds which may be beneficial to the overall casting process. Powered rotation obviously also reduces the effort required by the ladle operator and allows high volumes of molten metal to be transferred and poured for long periods without operator fatigue. Where the ladle is fitted with a manually operated gearbox, the type of gearbox most commonly used is the worm and wheel design because in most practical circumstances, and when correctly maintained it can be considered as "self-locking" and does not need an internal friction brake to regulate the tilting speed of the ladle. Other types of gear system can also be used but they have to be fitted with an additional braking system that can hold the ladle if the operator takes his hand off the hand-wheel.
Lip-axis ladles may also use hydraulic rams to tilt the ladle. The largest ladles are un-geared and are typically poured using a special, two-winch crane, where the main winch carries the ladle while the second winch engages a lug at the bottom of the ladle. Raising the second winch then rotates the ladle on its trunnions.
Ladles are often designed for special purposes such as adding alloys to the molten metal. Ladles may also have porous plugs inserted into the base, so inert gases can be bubbled through the ladle to enhance alloying or metallic treatment practices. | 0 | Metallurgy |
The involvement of miRNAs in diseases has led scientists to become more interested in the role of additional protein complexes, like microprocessor, that have the ability to influence or modulate the function and expression of miRNAs. Microprocessor complex component, DGCR8, is affected through the micro-deletion of 22q11.2, a small portion of chromosome 22. This deletion causes irregular processing of miRNAs which leads to DiGeorge Syndrome. | 1 | Gene expression + Signal Transduction |
The apparatus for testing consists of a closed testing cabinet/chamber, where a salt water (5% NaCl) solution is atomized by means of spray nozzle(s) using pressurized air. This produces a corrosive environment of dense salt water fog (also referred to as a mist or spray) in the chamber, so that test samples exposed to this environment are subjected to severely corrosive conditions. Chamber volumes vary from supplier to supplier. If there is a minimum volume required by a particular salt spray test standard, this will be clearly stated and should be complied with. There is a general historical consensus that larger chambers can provide a more homogeneous testing environment.
Variations to the salt spray test solutions depend upon the materials to be tested. The most common test for steel based materials is the Neutral Salt Spray test (often abbreviated to NSS) which reflects the fact that this type of test solution is prepared to a neutral pH of 6.5 to 7.2. To maintain a neutral pH, hydrochloric acid or sodium hydroxide are added to reduce or increase pH into the required range. Results are represented generally as testing hours in NSS without appearance of corrosion products (e.g. 720 h in NSS according to ISO 9227). Synthetic seawater solutions are also commonly specified by some companies and standards. Other test solutions have other chemicals added including acetic acid (often abbreviated to ASS) and acetic acid with copper chloride (often abbreviated to CASS) each one chosen for the evaluation of decorative coatings, such as electroplated copper-nickel-chromium, electroplated copper-nickel or anodized aluminum. These acidified test solutions generally have a pH of 3.1 to 3.3
Some sources do not recommend using ASS or CASS test cabinets interchangeably for NSS tests, due to the risk of cross-contamination. It is claimed that a thorough cleaning of the cabinet after CASS test is very difficult. ASTM does not address this issue, but ISO 9227 does not recommend it and if it is to be done, advocates a thorough cleaning.
Although the majority of salt spray tests are continuous, i.e.; the samples under test are exposed to the continuous generation of salt fog for the entire duration of the test, a few do not require such exposure. Such tests are commonly referred to as modified salt spray tests. ASTM G85 is an example of a test standard which contains several modified salt spray tests which are variations to the basic salt spray test. | 0 | Metallurgy |
The PHLPP isoforms (PH domain and Leucine rich repeat Protein Phosphatases) are a pair of protein phosphatases, PHLPP1 and PHLPP2, that are important regulators of Akt serine-threonine kinases (Akt1, Akt2, Akt3) and conventional/novel protein kinase C (PKC) isoforms. PHLPP may act as a tumor suppressor in several types of cancer due to its ability to block growth factor-induced signaling in cancer cells.
PHLPP dephosphorylates Ser-473 (the hydrophobic motif) in Akt, thus partially inactivating the kinase.
In addition, PHLPP dephosphorylates conventional and novel members of the protein kinase C family at their hydrophobic motifs, corresponding to Ser-660 in PKCβII. | 1 | Gene expression + Signal Transduction |
The ores of base metals are often sulfides. In recent centuries, reverberatory furnaces have been used to keep the charge being smelted separately from the fuel. Traditionally, they were used for the first step of smelting: forming two liquids, one an oxide slag containing most of the impurities, and the other a sulfide matte containing the valuable metal sulfide and some impurities. Such "reverb" furnaces are today about 40 meters long, 3 meters high, and 10 meters wide. Fuel is burned at one end to melt the dry sulfide concentrates (usually after partial roasting) which are fed through openings in the roof of the furnace. The slag floats over the heavier matte and is removed and discarded or recycled. The sulfide matte is then sent to the converter. The precise details of the process vary from one furnace to another depending on the mineralogy of the ore body.
While reverberatory furnaces produced slags containing very little copper, they were relatively energy inefficient and off-gassed a low concentration of sulfur dioxide that was difficult to capture; a new generation of copper smelting technologies has supplanted them. More recent furnaces exploit bath smelting, top-jetting lance smelting, flash smelting, and blast furnaces. Some examples of bath smelters include the Noranda furnace, the Isasmelt furnace, the Teniente reactor, the Vunyukov smelter, and the SKS technology. Top-jetting lance smelters include the Mitsubishi smelting reactor. Flash smelters account for over 50% of the world's copper smelters. There are many more varieties of smelting processes, including the Kivset, Ausmelt, Tamano, EAF, and BF. | 0 | Metallurgy |
Epileptic seizures occur when there is synchrony of electrical waves in the brain. Knowing the role that ephaptic coupling plays in maintaining synchrony in electrical signals, it makes sense to look for ephaptic mechanisms in this type of pathology. One study suggested that cortical cells represent an ideal place to observe ephaptic coupling due to the tight packing of axons, which allows for interactions between their electrical fields. They tested the effects of changing extracellular space (which affects local electrical fields) and found that one can block epileptic synchronization independent of chemical synapse manipulation simply by increasing the space between cells. Later, a model was created to predict this phenomenon and showed scenarios with greater extracellular spacing that effectively blocked epileptic synchronization in the brain. | 1 | Gene expression + Signal Transduction |
Most, if not all, metals can be sintered. This applies especially to pure metals produced in vacuum which suffer no surface contamination. Sintering under atmospheric pressure requires the use of a protective gas, quite often endothermic gas. Sintering, with subsequent reworking, can produce a great range of material properties. Changes in density, alloying, and heat treatments can alter the physical characteristics of various products. For instance, the Youngs modulus E' of sintered iron powders remains somewhat insensitive to sintering time, alloying, or particle size in the original powder for lower sintering temperatures, but depends upon the density of the final product:
where D is the density, E is Youngs modulus and d' is the maximum density of iron.
Sintering is static when a metal powder under certain external conditions may exhibit coalescence, and yet reverts to its normal behavior when such conditions are removed. In most cases, the density of a collection of grains increases as material flows into voids, causing a decrease in overall volume. Mass movements that occur during sintering consist of the reduction of total porosity by repacking, followed by material transport due to evaporation and condensation from diffusion. In the final stages, metal atoms move along crystal boundaries to the walls of internal pores, redistributing mass from the internal bulk of the object and smoothing pore walls. Surface tension is the driving force for this movement.
A special form of sintering (which is still considered part of powder metallurgy) is liquid-state sintering in which at least one but not all elements are in a liquid state. Liquid-state sintering is required for making cemented carbide and tungsten carbide.
Sintered bronze in particular is frequently used as a material for bearings, since its porosity allows lubricants to flow through it or remain captured within it. Sintered copper may be used as a wicking structure in certain types of heat pipe construction, where the porosity allows a liquid agent to move through the porous material via capillary action. For materials that have high melting points such as molybdenum, tungsten, rhenium, tantalum, osmium and carbon, sintering is one of the few viable manufacturing processes. In these cases, very low porosity is desirable and can often be achieved.
Sintered metal powder is used to make frangible shotgun shells called breaching rounds, as used by military and SWAT teams to quickly force entry into a locked room. These shotgun shells are designed to destroy door deadbolts, locks and hinges without risking lives by ricocheting or by flying on at lethal speed through the door. They work by destroying the object they hit and then dispersing into a relatively harmless powder.
Sintered bronze and stainless steel are used as filter materials in applications requiring high temperature resistance while retaining the ability to regenerate the filter element. For example, sintered stainless steel elements are employed for filtering steam in food and pharmaceutical applications, and sintered bronze in aircraft hydraulic systems.
Sintering of powders containing precious metals such as silver and gold is used to make small jewelry items. Evaporative self-assembly of colloidal silver nanocubes into supercrystals has been shown to allow the sintering of electrical joints at temperatures lower than 200°C. | 0 | Metallurgy |
Electrometallurgy is a method in metallurgy that uses electrical energy to produce metals by electrolysis. It is usually the last stage in metal production and is therefore preceded by pyrometallurgical or hydrometallurgical operations. The electrolysis can be done on a molten metal oxide (smelt electrolysis) which is used for example to produce aluminium from aluminium oxide via the Hall-Hérault process. Electrolysis can be used as a final refining stage in pyrometallurgical metal production (electrorefining) and it is also used for reduction of a metal from an aqueous metal salt solution produced by hydrometallurgy (electrowinning). | 0 | Metallurgy |
In normal fatigue-testing of smooth specimens, about 90 percent is spent in crack nucleation and only the remaining 10 percent in crack propagation. However, in corrosion fatigue crack nucleation is facilitated by corrosion; typically, about 10 percent of life is sufficient for this stage. The rest (90 percent) of life is spent in crack propagation. Thus, it is more useful to evaluate crack-propagation behavior during corrosion fatigue.
Fracture mechanics uses pre-cracked specimens, effectively measuring crack-propagation behavior. For this reason, emphasis is given to crack-propagation velocity measurements (using fracture mechanics) to study corrosion fatigue. Since fatigue crack grows in a stable fashion below the critical stress-intensity factor for fracture (fracture toughness), the process is called sub-critical crack growth.
The diagram on the right shows typical fatigue-crack-growth behavior. In this log-log plot, the crack-propagation velocity is plotted against the applied stress-intensity range. Generally there is a threshold stress-intensity range, below which crack-propagation velocity is insignificant. Three stages may be visualized in this plot. Near the threshold, crack-propagation velocity increases with increasing stress-intensity range. In the second region, the curve is nearly linear and follows Paris' law(6); in the third region crack-propagation velocity increases rapidly, with the stress-intensity range leading to fracture at the fracture-toughness value.
Crack propagation under corrosion fatigue may be classified as a) true corrosion fatigue, b) stress corrosion fatigue or c) a combination of true, stress and corrosion fatigue. | 0 | Metallurgy |
Metal spraying equipment uses compressed gases which create noise. Sound levels vary with the type of spraying equipment, the material being sprayed, and the operating parameters. Typical sound pressure levels are measured at 1 meter behind the arc. | 0 | Metallurgy |
Modular screen media is typically 1 foot large by 1 or 2 feet long (4 feet long for ISEPREN WS 85 ) steel reinforced polyurethane or rubber panels. They are installed on a flat deck (no crown) that normally has a larger surface than a tensioned deck. This larger surface design compensates for the fact that rubber and polyurethane modular screen media offers less open area than wire cloth. Over the years, numerous ways have been developed to attach modular panels to the screen deck stringers (girders). Some of these attachment systems have been or are currently patented. Self-cleaning screen media is also available on this modular system.
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The Cephalodiscidae mitochondrial code (translation table 33) is a genetic code used by the mitochondrial genome of Cephalodiscidae (Pterobranchia). The Pterobranchia are one of the two groups in the Hemichordata which together with the Echinodermata and Chordata form the major clades of deuterostomes.
Code 33 is very similar to the mitochondrial code 24 for the Pterobranchia, which also belong to the Hemichordata, except that it uses UAA for tyrosine rather than as a stop codon.
This code shares with many other mitochondrial codes the reassignment of the UGA STOP to tryptophan, and AGG and AGA to an amino acid other than arginine. However, the assignment of AGG to lysine in pterobranchian mitogenomes is not found elsewhere in deuterostome mitochondria but it occurs in some taxa of Arthropoda. | 1 | Gene expression + Signal Transduction |
While there are many methods of detecting fake precious metals, there are realistically only two options available for verifying the marked fineness of metal as being reasonably accurate: assaying the metal (which requires destroying it), or using X-ray fluorescence (XRF). XRF will measure only the outermost portion of the piece of metal and so may get misled by thick plating.
That becomes a concern because it would be possible for an unscrupulous refiner to produce precious metals bars that are slightly less pure than marked on the bar. A refiner doing $1 billion of business each year that marked .980 pure bars as .999 fine would make about an extra $20 million in profit. In the United States, the actual purity of gold articles must be no more than .003 less than the marked purity (e.g. .996 fine for gold marked .999 fine), and the actual purity of silver articles must be no more than .004 less than the marked purity. | 0 | Metallurgy |
As water evaporates in the boiler, the concentration of sodium carbonate increases in the boiler. In high pressure boilers, sodium carbonate is used in softening of water by lime soda process, due to this some sodium carbonate maybe left behind in the water. As the concentration of sodium carbonate increases, it undergoes hydrolysis to form sodium hydroxide.
The presence of sodium hydroxide makes the water alkaline in nature. This alkaline water enters minute cracks present in the inner walls of the boiler by capillary action. Inside the cracks, the water evaporates and the amount of hydroxide keeps increasing progressively. The concentrated area with high stress works as anode and diluted area works as cathode. At anode, sodium hydroxide attacks the surrounding material and then dissolves the iron of the boiler as sodium ferrate forming rust. This causes embrittlement of boiler parts like rivets, bends and joints, which are under stress. | 0 | Metallurgy |
A widely publicized study suggested that humans can detect more than one trillion different odors. This finding has been disputed. Critics argued that the methodology used for the estimation was fundamentally flawed, showing that applying the same argument for better-understood sensory modalities, such as vision or audition, leads to wrong conclusions. Other researchers have also showed that the result is extremely sensitive to the precise details of the calculation, with small variations changing the result over dozens of orders of magnitude, possibly going as low as a few thousand. The authors of the original study have argued that their estimate holds as long as it is assumed that odor space is sufficiently high-dimensional. | 1 | Gene expression + Signal Transduction |
Dehydroretinal (3,4-dehydroretinal) is a derivative metabolite of retinal belonging to the group of vitamin A as a retinaldehyde form, besides the endogenously present 3,4-dehydroretinol and 3,4-dehydroretinoic acid.
The livers of some freshwater fishes and some fish found in India contain a higher ratio of dehydroretinal to retinal than do other species. | 1 | Gene expression + Signal Transduction |
At pressures above approximately 10-13 GPa and temperatures up to around 700 K, α-iron changes into a hexagonal close-packed (hcp) structure, which is also known as ε-iron or hexaferrum; the higher-temperature γ-phase also changes into ε-iron, but generally requires far higher pressures as temperature increases. The triple point of hexaferrum, ferrite, and austenite is 10.5 GPa at 750 K. Antiferromagnetism in alloys of epsilon-Fe with Mn, Os and Ru has been observed. | 0 | Metallurgy |
*G are involved in Rho family GTPase signaling (see Rho family of GTPases). This is through the RhoGEF superfamily involving the RhoGEF domain of the proteins' structures). These are involved in control of cell cytoskeleton remodeling, and thus in regulating cell migration. | 1 | Gene expression + Signal Transduction |
The slippery sequence for a +1 frameshift signal does not have the same motif, and instead appears to function by pausing the ribosome at a sequence encoding a rare amino acid. Ribosomes do not translate proteins at a steady rate, regardless of the sequence. Certain codons take longer to translate, because there are not equal amounts of tRNA of that particular codon in the cytosol. Due to this lag, there exist in small sections of codons sequences that control the rate of ribosomal frameshifting. Specifically, the ribosome must pause to wait for the arrival of a rare tRNA, and this increases the kinetic favorability of the ribosome and its associated tRNA slipping into the new frame. In this model, the change in reading frame is caused by a single tRNA slip rather than two. | 1 | Gene expression + Signal Transduction |
Artificial gene synthesis, or simply gene synthesis, refers to a group of methods that are used in synthetic biology to construct and assemble genes from nucleotides de novo. Unlike DNA synthesis in living cells, artificial gene synthesis does not require template DNA, allowing virtually any DNA sequence to be synthesized in the laboratory. It comprises two main steps, the first of which is solid-phase DNA synthesis, sometimes known as DNA printing. This produces oligonucleotide fragments that are generally under 200 base pairs. The second step then involves connecting these oligonucleotide fragments using various DNA assembly methods. Because artificial gene synthesis does not require template DNA, it is theoretically possible to make a completely synthetic DNA molecule with no limits on the nucleotide sequence or size.
Synthesis of the first complete gene, a yeast tRNA, was demonstrated by Har Gobind Khorana and coworkers in 1972. Synthesis of the first peptide- and protein-coding genes was performed in the laboratories of Herbert Boyer and Alexander Markham, respectively. More recently, artificial gene synthesis methods have been developed that will allow the assembly of entire chromosomes and genomes. The first synthetic yeast chromosome was synthesised in 2014, and entire functional bacterial chromosomes have also been synthesised. In addition, artificial gene synthesis could in the future make use of novel nucleobase pairs (unnatural base pairs). | 1 | Gene expression + Signal Transduction |
The Rare Earths Facility was a production plant for various chemicals and metals including thorium, uranium, and radium. It was located in West Chicago, Illinois, USA. | 0 | Metallurgy |
On June 28, 2007, a team at the J. Craig Venter Institute published an article in Science Express, saying that they had successfully transplanted the natural DNA from a Mycoplasma mycoides bacterium into a Mycoplasma capricolum cell, creating a bacterium which behaved like a M. mycoides.
On Oct 6, 2007, Craig Venter announced in an interview with UKs The Guardian newspaper that the same team had synthesized a modified version of the single chromosome of Mycoplasma genitalium artificially. The chromosome was modified to eliminate all genes which tests in live bacteria had shown to be unnecessary. The next planned step in this minimal genome project is to transplant the synthesized minimal genome into a bacterial cell with its old DNA removed; the resulting bacterium will be called Mycoplasma laboratorium. The next day the Canadian bioethics group, ETC Group issued a statement through their representative, Pat Mooney, saying Venters "creation" was "a chassis on which you could build almost anything". The synthesized genome had not yet been transplanted into a working cell.
On May 21, 2010, Science reported that the Venter group had successfully synthesized the genome of the bacterium Mycoplasma mycoides from a computer record, and transplanted the synthesized genome into the existing cell of a Mycoplasma capricolum bacterium that had its DNA removed. The "synthetic" bacterium was viable, i.e. capable of replicating billions of times. The team had originally planned to use the M. genitalium bacterium they had previously been working with, but switched to M. mycoides because the latter bacterium grows much faster, which translated into quicker experiments. Venter describes it as "the first species.... to have its parents be a computer". The transformed bacterium is dubbed "Synthia" by ETC. A Venter spokesperson has declined to confirm any breakthrough at the time of this writing. | 1 | Gene expression + Signal Transduction |
RNA editing (also RNA modification) is a molecular process through which some cells can make discrete changes to specific nucleotide sequences within an RNA molecule after it has been generated by RNA polymerase. It occurs in all living organisms and is one of the most evolutionarily conserved properties of RNAs. RNA editing may include the insertion, deletion, and base substitution of nucleotides within the RNA molecule. RNA editing is relatively rare, with common forms of RNA processing (e.g. splicing, 5-capping, and 3-polyadenylation) not usually considered as editing. It can affect the activity, localization as well as stability of RNAs, and has been linked with human diseases.
RNA editing has been observed in some tRNA, rRNA, mRNA, or miRNA molecules of eukaryotes and their viruses, archaea, and prokaryotes. RNA editing occurs in the cell nucleus, as well as within mitochondria and plastids. In vertebrates, editing is rare and usually consists of a small number of changes to the sequence of the affected molecules. In other organisms, such as squids, extensive editing (pan-editing) can occur; in some cases the majority of nucleotides in an mRNA sequence may result from editing. More than 160 types of RNA modifications have been described so far.
RNA-editing processes show great molecular diversity, and some appear to be evolutionarily recent acquisitions that arose independently. The diversity of RNA editing phenomena includes nucleobase modifications such as cytidine (C) to uridine (U) and adenosine (A) to inosine (I) deaminations, as well as non-template nucleotide additions and insertions. RNA editing in mRNAs effectively alters the amino acid sequence of the encoded protein so that it differs from that predicted by the genomic DNA sequence. | 1 | Gene expression + Signal Transduction |
Sphingosine (Sph) is formed by the action of ceramidase (CDase) enzymes on ceramide in the lysosome. Sph can also be formed in the extracellular (outer leaflet) side of the plasma membrane by the action of neutral CDase enzyme. Sph then is either recycled back to ceramide or phosphorylated by one of the sphingosine kinase enzymes, SK1 and SK2. The product sphingosine-1-phosphate (S1P) can be dephosphorylated in the ER to regenerate sphingosine by certain S1P phosphatase enzymes within cells, where the salvaged Sph is recycled to ceramide. Sphingosine is a single-chain lipid (usually 18 carbons in length), rendering it to have sufficient solubility in water. This explains its ability to move between membranes and to flip-flop across a membrane. Estimates conducted at physiological pH show that approximately 70% of sphingosine remains in membranes while the remaining 30% is water-soluble. Sph that is formed has sufficient solubility in the liquid found inside cells (cytosol). Thus, Sph may come out of the lysosome and move to the ER without the need for transport via proteins or membrane-enclosed sacs called vesicles. However, its positive charge favors partitioning in lysosomes. It is proposed that the role of SK1 located near or in the lysosome is to ‘trap’ Sph via phosphorylation.
It is important to note that since sphingosine exerts surfactant activity, it is one of the sphingolipids found at lowest cellular levels. The low levels of Sph and their increase in response to stimulation of cells, primarily by activation of ceramidase by growth-inducing proteins such as platelet-derived growth factor and insulin-like growth factor, is consistent with its function as a second messenger. It was found that immediate hydrolysis of only 3 to 10% of newly generated ceramide may double the levels of Sph. Treatment of HL60 cells (a type of leukemia cell line) by a plant-derived organic compound called phorbol ester increased Sph levels threefold, whereby the cells differentiated into white blood cells called macrophages. Treatment of the same cells by exogenous Sph caused apoptosis. A specific protein kinase phosphorylates 14-3-3, otherwise known as sphingosine-dependent protein kinase 1 (SDK1), only in the presence of Sph.
Sph is also known to interact with protein targets such as the protein kinase H homologue (PKH) and the yeast protein kinase (YPK). These targets in turn mediate the effects of Sph and its related sphingoid bases, with known roles in regulating the actin cytoskeleton, endocytosis, the cell cycle and apoptosis. It is important to note however that the second messenger function of Sph is not yet established unambiguously. | 1 | Gene expression + Signal Transduction |
Eukaryotic Initiation Factor 2 (eIF2) is an eukaryotic initiation factor. It is required for most forms of eukaryotic translation initiation. eIF2 mediates the binding of tRNA to the ribosome in a GTP-dependent manner. eIF2 is a heterotrimer consisting of an alpha (also called subunit 1, EIF2S1), a beta (subunit 2, EIF2S2), and a gamma (subunit 3, EIF2S3) subunit.
Once the initiation phase has completed, eIF2 is released from the ribosome bound to GDP as an inactive binary complex. To participate in another round of translation initiation, this GDP must be exchanged for GTP. | 1 | Gene expression + Signal Transduction |
The atoms in the GB are normally in a higher energy state than their equivalent in the bulk material. This is due to their more stretched bonds, which gives rise to a GB tension . This extra energy that the atoms possess is called the grain boundary energy, . The grain will want to minimize this extra energy, thus striving to make the grain boundary area smaller and this change requires energy.
"Or, in other words, a force has to be applied, in the plane of the grain boundary and acting along a line in the grain-boundary area, in order to extend the grain-boundary area in the direction of the force. The force per unit length, i.e. tension/stress, along the line mentioned is σGB. On the basis of this reasoning it would follow that:
with dA as the increase of grain-boundary area per unit length along the line in the grain-boundary area considered."
The GB tension can also be thought of as the attractive forces between the atoms at the surface and the tension between these atoms is due to the fact that there is a larger interatomic distance between them at the surface compared to the bulk (i.e. surface tension). When the surface area becomes bigger the bonds stretch more and the GB tension increases. To counteract this increase in tension there must be a transport of atoms to the surface keeping the GB tension constant. This diffusion of atoms accounts for the constant surface tension in liquids. Then the argument,
holds true. For solids, on the other hand, diffusion of atoms to the surface might not be sufficient and the surface tension can vary with an increase in surface area.
For a solid, one can derive an expression for the change in Gibbs free energy, dG, upon the change of GB area, dA. dG is given by
which gives
is normally expressed in units of while is normally expressed in units of since they are different physical properties. | 0 | Metallurgy |
Schulze in 1967 defined intermetallic compounds as solid phases containing two or more metallic elements, with optionally one or more non-metallic elements, whose crystal structure differs from that of the other constituents. Under this definition, the following are included:
# Electron (or Hume-Rothery) compounds
# Size packing phases. e.g. Laves phases, Frank–Kasper phases and Nowotny phases
# Zintl phases
The definition of a metal is taken to include:
# post-transition metals, i.e. aluminium, gallium, indium, thallium, tin, lead, and bismuth.
# metalloids, e.g. silicon, germanium, arsenic, antimony and tellurium.
Homogeneous and heterogeneous solid solutions of metals, and interstitial compounds such as the carbides and nitrides are excluded under this definition. However, interstitial intermetallic compounds are included, as are alloys of intermetallic compounds with a metal. | 0 | Metallurgy |
Type S (90%Pt/10%Rh–Pt, by weight) thermocouples, similar to type R, are used up to 1600 °C. Before the introduction of the International Temperature Scale of 1990 (ITS-90), precision type-S thermocouples were used as the practical standard thermometers for the range of 630 °C to 1064 °C, based on an interpolation between the freezing points of antimony, silver, and gold. Starting with ITS-90, platinum resistance thermometers have taken over this range as standard thermometers. | 0 | Metallurgy |
Several methods of RNA splicing occur in nature; the type of splicing depends on the structure of the spliced intron and the catalysts required for splicing to occur. | 1 | Gene expression + Signal Transduction |
CCL7 was first characterized from osteosarcoma supernatant. CCL7 consists of 99 amino acids, which contains 23-amino acid signal peptide. The mature protein about 76 amino acids is secreted after cleavage of the signal peptide. In contrast to most chemokines, CCL7 exists in a general monomeric form, differing from the dimer formed in a highly concentrated solution.
CCL7 can exist in four different glycotypes with a molecular weight 11, 13, 17 and 18 kDa in COS cells.
CCL7 mediates effects on the immune cell types through binding to numerous receptors, including CCR1, CCR2, CCR3, CCR5, and CCR10. These receptors belongs to the G protein-coupled seven-transmembrane receptors. CCL7 can also interact with cell surface glycosaminoglycans (GAGs) present on all animal cell surfaces. | 1 | Gene expression + Signal Transduction |
* Genomic Imprinting
* Paramutation
* Transposon silencing (or Histone Modifications)
* Transgene silencing
* Position effect
* RNA-directed DNA methylation | 1 | Gene expression + Signal Transduction |
In the iron and steel industry, direct reduction is a set of processes for obtaining iron from iron ore, by reducing iron oxides without melting the metal. The resulting product is pre-reduced iron ore.
Historically, direct reduction was used to obtain a burr in a low furnace. At the beginning of the 20th century, this process was abandoned in favor of the blast furnace, which produces iron in two stages (reduction-melting to produce cast iron, followed by refining in a converter).
However, various processes were developed in the course of the 20th century and, since the 1970s, the production of pre-reduced iron ore has undergone remarkable industrial development, notably with the rise of the Midrex process. Designed to replace the blast furnace, these processes have so far only proved profitable in certain economic contexts, which still limits this sector to less than 5% of world steel production. | 0 | Metallurgy |
Falconbridge Limited in mid-1981 commissioned a copper smelter and refinery near Timmins, Ontario, to treat concentrate from its Kidd Mine. However, at the outset, the quality of the cathode copper produced in the Kidd refinery suffered from the presence of higher than usual concentrations of lead and selenium in the copper smelter’s anodes. Kidd cathode copper was not able to meet its customers’ specifications and obtaining product certification for the London Metal Exchange (“LME”) became a key focus.
After several process improvements were instigated, it was ultimately realised that the use of copper starter sheets was preventing the Kidd refinery meeting its cathode quality targets. Test work then began on the use of permanent stainless-steel cathodes. Preliminary tests using full-scale titanium blanks showed a reduction in the lead content of the cathode copper of a factor of four and a six-fold reduction in the selenium content, compared with the use of copper starter sheets.
The focus then shifted to developing a stripping machine, to develop stainless steel cathodes incorporating the existing header bars and evaluating edge-strip technology. The company’s board of directors gave approval for the conversion of the refinery to the Kidd technology in April 1985. The conversion was completed in 1986 and the Kidd refinery became the third to install permanent cathode and automated stripping technology.
Falconbridge began marketing the technology in 1992, after many requests from other refinery operators. Thus, the Kidd Process created competition between two suppliers of permanent cathode technology. The main differences between them were the cathode header bar, edge stripping and the stripping machine technology.
In contrast to the stainless steel header bar then used in the Isa Process cathode, the Kidd Process cathode used a solid copper header bar, which was welded onto the stainless steel sheet. This gave a lower voltage drop (by 8–10 millivolts) than the Isa Process cathode.
The Isa Process technology used the waxed edge at the bottom of the cathode plate to stop the copper depositing around the plate’s bottom to form a single mass of copper running from the top of one side of the cathode plate around the bottom to the top of the other side. The copper was stripped from the cathode plates as two separate sheets. The Kidd Process technology did not use wax, as it was thought that it could exacerbate the impurity problems with which the plant had been struggling. At Kidd, the stripping approach was to remove the copper from the cathode plate as a single V-shaped cathode product, akin to a taco shell.
The Kidd Process initially used a “carousel” stripping machine, but a linear installation was subsequently developed to provide machines with lower to medium stripping capacities for electrowinning plants and smaller refineries. The linear stripping machines, first installed in 1996, were more compact, less complex and had lower installation costs than the carousel machines. | 0 | Metallurgy |
Rapid advance in cancer genomics and high-throughput ChIP-chip, ChIP-Seq and Bisulfite sequencing methods are providing more insight into role of chromatin remodeling in transcriptional regulation and role in cancer. | 1 | Gene expression + Signal Transduction |
The microprocessor complex consists minimally of two proteins: Drosha, a ribonuclease III enzyme; and DGCR8, a double-stranded RNA binding protein. (DGCR8 is the name used in mammalian genetics, abbreviated from "DiGeorge syndrome critical region 8"; the homologous protein in model organisms such as flies and worms is called Pasha, for Partner of Drosha.) The stoichiometry of the minimal complex was at one point experimentally difficult to determine, but it has been demonstrated to be a heterotrimer of two DGCR8 proteins and one Drosha.
In addition to the minimal catalytically active microprocessor components, other cofactors such as DEAD box RNA helicases and heterogeneous nuclear ribonucleoproteins may be present in the complex to mediate the activity of Drosha. Some miRNAs are processed by microprocessor only in the presence of specific cofactors. | 1 | Gene expression + Signal Transduction |
* CPPs have been used to transport a variety of biomolecules into cells in both vitro and in vivo. One must be cautious of which CPPs are used. For example, different CPPs promote movement into different cell types and cellular components.
* If the TIVA tag is not used within 3 months of synthesis, the FRET signal is weakened.
* The storage of TIVA tag requires a -80 °C freezer and should be in dried form. | 1 | Gene expression + Signal Transduction |
Researchers at Sandia Labs, Ames National Laboratory and Iowa State University reported a 3D-printed superalloy composed of 42% aluminum, 25% titanium, 13% niobium, 8% zirconium, 8% molybdenum and 4% tantalum. Most alloys are made chiefly of one primary element, combined with low amounts of other elements. In contrast MPES have substantial amounts of three or more elements.
Such alloys promise improvements on high-temperature applications, strength-to-weight, fracture toughness, corrosion and radiation resistance, wear resistance, and others. They reported hardness and density of 1.8–2.6 GPa-cm/g, which surpasses all known alloys, including intermetallic compounds, titanium aluminides, refractory MPEAs, and conventional Ni-based superalloys. This represents a 300% improvement over Inconel 718 based on measured peak hardness of 4.5 GPa and density of 8.2 g/cm, (0.55 GPa-cm/g).
The material is stable at 800 °C, hotter than the 570+ °C found in typical coal-based power plants.
The researchers acknowledged that the 3D printing process produces microscopic cracks when forming large parts, and that the feedstock includes metals that limit applicability in cost-sensitive applications. | 0 | Metallurgy |
Despite the high number of MAPK genes, MAPK pathways of higher plants were studied less than animal or fungal ones. Although their signaling appears very complex, the MPK3, MPK4 and MPK6 kinases of Arabidopsis thaliana are key mediators of responses to osmotic shock, oxidative stress, response to cold and involved in anti-pathogen responses. Asai et al. 2002s model of MAPK mediated immunity passes the effector recognition signal from FLS2 ⇨ MEKK1 ⇨ MKK4 or MKK5 ⇨ MPK3 and MPK6 ⇨ WRKY22 or WRKY29. However the work of Mészáros et al. 2006 and Suarez-Rodriguez et al.' 2007 give other orders for this pathway and it is possible that these are parallel pathways operating simultaneously. They are also involved in morphogenesis, since MPK4 mutants display severe dwarfism. | 1 | Gene expression + Signal Transduction |
The phrase originates from the French word espoilelier, a verb conveying the meaning: to seize by violence, to plunder, to take by force. | 0 | Metallurgy |
High temperature materials are valuable for energy conversion and energy production applications. Maximum energy conversion efficiency is desired in such applications, in accord with the Carnot cycle. Because Carnot efficiency is limited by the temperature difference between the hot and cold reservoirs, higher operating temperatures increase energy conversion efficiency. Operating temperatures are limited by superalloys, limiting applications to around 1000 °C-1400 °C. Energy applications include:
* Solar thermal power plants (stainless steel rods containing heated water)
* Steam turbines (turbine blades and boiler housing)
* Heat exchangers for nuclear reactor systems
Alumina-forming stainless steel is weldable and has potential for use in automotive applications, such as for high temperature exhaust piping and in heat capture and reuse. | 0 | Metallurgy |
A base metal, such as iron (Fe) goes into aqueous solution as positively charged cation, Fe. As the metal is oxidized under anaerobic conditions by the protons of water, H ions are reduced to form molecular H. This can be written in the following ways under acidic and neutral conditions respectively:
:Fe + 2 H → Fe + H
:Fe + 2 HO → Fe(OH) + H
Usually, a thin film of molecular hydrogen forms on the metal. Sulfate-reducing bacteria oxidize the molecular hydrogen to produce hydrogen sulfide ions (HS) and water:
:4 H + SO → HS + 3 HO + OH
The iron ions partly precipitate to form iron (II) sulfide. Another reaction occurs between iron and water producing iron hydroxide.
:Fe + HS → FeS + H
:3 Fe + 6 HO → 3 Fe(OH) + 6 H
The net equation comes to:
:4 Fe + SO + H + 3 HO → FeS + 3 Fe(OH) + OH
This form of corrosion by sulfate-reducing bacteria can, in this way, be far more harmful than anaerobic corrosion. | 0 | Metallurgy |
The cell used in this process consists of an iron tank lined with carbon at the bottom.
A molten alloy of copper, crude aluminium and silicon is used as the anode. It forms the lowermost layer in the cell.
The middle layer consists of molten mixture of fluorides of sodium, aluminium and barium (cryolite + BaF).
The uppermost layer consists of molten aluminium.
A set of graphite rods dipped in molten aluminium serve as the cathode.
During electrolysis, Al ions from the middle layer migrate to the upper layer, where they are reduced to aluminum by gaining 3 electrons.
Equal numbers of Al ions are produced in the lower layer. These ions migrate to the middle layer. Pure aluminium is tapped off from time to time. The Hoopes process gives about 99.99% pure aluminium. | 0 | Metallurgy |
Lilleby closed on the same day Norway was attacked by Nazi Germany, but it did not remain closed for long. The Norwegian aluminium industry was of great strategic importance for the German government, which requested that Lilleby resume operation right away. Birger Solberg was placed in charge, because professor Pedersen had left with his family to Sweden. Solberg was dismissed the day that Pederson returned, undoubtedly related to his views on the occupation, which differed from Professor Pedersen's views: Pedersen was a supporter of Nazi Germany and wanted to collaborate with the occupation.
During the war, the plant was geared mostly towards aluminium, which was more important for the German war effort; however, many employees sabotaged the work in order to keep productivity low. | 0 | Metallurgy |
Based on the method developed by Poliak and Jonas, a few models are developed in order to describe the critical strain for the onset of DRX as a function of the peak strain of the stress–strain curve. The models are derived for the systems with single peak, i.e. for the materials with medium to low stacking fault energy values. The models can be found in the following papers:
* [https://arxiv.org/abs/1405.0196 Determination of flow stress and the critical strain for the onset of dynamic recrystallization using a sine function]
* [https://dx.doi.org/10.1016/j.matdes.2013.08.055 Determination of flow stress and the critical strain for the onset of dynamic recrystallization using a hyperbolic tangent function]
* [https://dx.doi.org/10.1016/j.matdes.2009.09.001 Determination of critical strain for initiation of dynamic recrystallization]
* [https://www.researchgate.net/publication/260337084_Characteristic_points_of_stressstrain_curve_at_high_temperature Characteristic points of stress–strain curve at high temperature]
The DRX behavior for systems with multiple peaks (and single peak as well) can be modeled considering the interaction of multiple grains during deformation. I. e. the ensemble model describes the transition between single and multi peak behavior based on the initial grain size. It can also describe the effect of transient changes of the strain rate on the shape of the flow curve. The model can be found in the following paper:
* [https://doi.org/10.1016/j.msea.2015.08.085 A new unified approach for modeling recrystallization during hot rolling of steel] | 0 | Metallurgy |
Red plague is an accelerated corrosion of copper when plated with silver. After storage, damage or use in high-humidity environment, cuprous oxide forms on the surface of the parts. The corrosion is identifiable by presence of patches of brown-red powder deposit on the exposed copper.
Red plague is caused by normally occurring electrode potential difference between the copper and silver, leading to galvanic corrosion occurring in pits or breaks in the silver plating. It develops in the presence of moisture and oxygen when the porosity of the silver layer allows them to come in contact with the copper-silver interface. It is an electrochemical corrosion—a copper-silver galvanic cell forms and the copper acts as sacrificial anode. In suitable conditions, the corrosion can proceed rather quickly and lead to total circuit failure.
More details can be seen in ESA document PSS-01-720, with details on determining the susceptibility of silver-plated copper wire to red plague corrosion found in ECSS-Q-ST-70-20C.
It is not to be confused with purple plague, a type of galvanic corrosion that occurs between gold and aluminum. | 0 | Metallurgy |
Before it was flooded, Norşuntepe was located on the Altınova Plain near the mouth of the Murat River (downstream from the town of Palu, Elazığ). It is now partially submerged by the reservoir created by the Keban Dam; its top is still above the water level. The site consists of a central hill or "acropolis" measuring and high, making it the largest tell in the area. The central hill is surrounded by lower terraces encompassing an area of . | 0 | Metallurgy |
SPIDR (scaffold protein involved in DNA repair) regulates the stability or assembly of RAD51 and DMC1 on single-stranded DNA. RAD51 and DMC1 are recombinases that act during mammalian meiosis to mediate strand exchange during the repair of DNA double-strand breaks by homologous recombination. | 1 | Gene expression + Signal Transduction |
The FLC operon is a conserved eukaryotic locus that is negatively associated with flowering via repression of genes needed for the development of the meristem to switch to a floral state in the plant species Arabidopsis thaliana. FLC expression has been shown be regulated by the presence of [https://www.uniprot.org/uniprot/P0DH90 FRIGIDA], and negatively correlates with decreases in temperature resulting in the prevention of vernalization. The degree to which expression decreases depends on the temperature and exposure time as seasons progress. After the downregulation of FLC expression, the potential for flowering is enabled. The regulation of FLC expression involves both genetic and epigenetic factors such as histone methylation and DNA methylation. Furthermore, a number of genes are cofactors act as negative transcription factors for FLC genes. FLC genes also have a large number of homologues across species that allow for specific adaptations in a range of climates. | 1 | Gene expression + Signal Transduction |
The thermocouple's behaviour is captured by a characteristic function , which needs only to be consulted at two arguments:
In terms of the Seebeck coefficients, the characteristic function is defined by
The constant of integration in this indefinite integral has no significance, but is conventionally chosen such that .
Thermocouple manufacturers and metrology standards organizations such as NIST provide tables of the function that have been measured and interpolated over a range of temperatures, for particular thermocouple types (see External links section for access to these tables). | 0 | Metallurgy |
Next to the potential antimicrobial functionality, quorum-sensing derived molecules, especially the peptides, are being investigated for their use in other therapeutic domains as well, including immunology, central nervous system disorders and oncology. Quorum-sensing peptides have been demonstrated to interact with cancer cells, as well as to permeate the blood–brain barrier reaching the brain parenchyma. | 1 | Gene expression + Signal Transduction |
The molecular organization of the nodes corresponds to their specialized function in impulse propagation. The level of sodium channels in the node versus the internode suggests that the number IMPs corresponds to sodium channels. Potassium channels are essentially absent in the nodal axolemma, whereas they are highly concentrated in the paranodal axolemma and Schwann cell membranes at the node. The exact function of potassium channels have not quite been revealed, but it is known that they may contribute to the rapid repolarization of the action potentials or play a vital role in buffering the potassium ions at the nodes. This highly asymmetric distribution of voltage-gated sodium and potassium channels is in striking contrast to their diffuse distribution in unmyelinated fibers.
The filamentous network subjacent to the nodal membrane contains cytoskeletal proteins called spectrin and ankyrin. The high density of ankyrin at the nodes may be functionally significant because several of the proteins that are populated at the nodes share the ability to bind to ankyrin with extremely high affinity. All of these proteins, including ankyrin, are enriched in the initial segment of axons which suggests a functional relationship. Now the relationship of these molecular components to the clustering of sodium channels at the nodes is still not known. Although some cell-adhesion molecules have been reported to be present at the nodes inconsistently; however, a variety of other molecules are known to be highly populated at the glial membranes of the paranodal regions where they contribute to its organization and structural integrity. | 1 | Gene expression + Signal Transduction |
The split gene theory is a theory of the origin of introns, long non-coding sequences in eukaryotic genes between the exons. The theory holds that the randomness of primordial DNA sequences would only permit small (< 600bp) open reading frames (ORFs), and that important intron structures and regulatory sequences are derived from stop codons. In this introns-first framework, the spliceosomal machinery and the nucleus evolved due to the necessity to join these ORFs (now "exons") into larger proteins, and that intronless bacterial genes are less ancestral than the split eukaryotic genes. The theory originated with Periannan Senapathy.
The theory provides solutions to key questions concerning the split gene architecture, including split eukaryotic genes, exons, introns, splice junctions, and branch points, based on the origin of split genes from random genetic sequences. It also provides possible solutions to the origin of the spliceosomal machinery, the nuclear boundary and the eukaryotic cell.
This theory led to the Shapiro–Senapathy algorithm, which provides the methodology for detecting the splice sites, exons and split genes in eukaryotic DNA, and which is the main method for detecting splice site mutations in genes that cause hundreds of diseases.
Split gene theory requires a separate origin of all eukaryotic species. It also requires that the simpler prokaryotes evolved from eukaryotes. This completely contradicts the scientific consensus about the formation of eukaryotic cells by endosymbiosis of bacteria. In 1994, Senapathy wrote a book about this aspect of his theory - The Independent Birth of Organisms. It proposed that all eukaryotic genomes were formed separately in a primordial pool. Dutch biologist Gert Korthoff criticized the theory by posing various problems that cannot be explained by a theory of independent origins. He pointed out that various eukaryotes need nurturing and called this the boot problem, in that even the initial eukaryote needed parental care. Korthoff notes that a large fraction of eukaryotes are parasites. Senapathys theory would require a coincidence to explain their existence. Senapathys theory cannot explain the strong evidence for common descent (homology, universal genetic code, embryology, fossil record.) | 1 | Gene expression + Signal Transduction |
Chemical milling or industrial etching is the subtractive manufacturing process of using baths of temperature-regulated etching chemicals to remove material to create an object with the desired shape. Other names for chemical etching include photo etching, chemical etching, photo chemical etching and photochemical machining. It is mostly used on metals, though other materials are increasingly important. It was developed from armor-decorating and printing etching processes developed during the Renaissance as alternatives to engraving on metal. The process essentially involves bathing the cutting areas in a corrosive chemical known as an etchant, which reacts with the material in the area to be cut and causes the solid material to be dissolved; inert substances known as maskants are used to protect specific areas of the material as resists. | 0 | Metallurgy |
As illustrated by the peroxisomal intracellular lactate shuttle described above, the interconversion of lactate and pyruvate between cellular compartments plays a key role in the oxidative state of the cell. Specifically, the interconversion of NAD+ and NADH between compartments has been hypothesized to occur in the mitochondria. However, the evidence for this is lacking, as both lactate and pyruvate are quickly metabolized inside the mitochondria. However, the existence of the peroxisomal lactate shuttle suggests that this redox shuttle could exist for other organelles. | 1 | Gene expression + Signal Transduction |
In metallurgy, non-ferrous metals are metals or alloys that do not contain iron (allotropes of iron, ferrite, and so on) in appreciable amounts.
Generally more costly than ferrous metals, non-ferrous metals are used because of desirable properties such as low weight (e.g. aluminium), higher conductivity (e.g. copper), non-magnetic properties or resistance to corrosion (e.g. zinc). Some non-ferrous materials are also used in the iron and steel industries. For example, bauxite is used as flux for blast furnaces, while others such as wolframite, pyrolusite, and chromite are used in making ferrous alloys.
Important non-ferrous metals include aluminium, copper, lead, tin, titanium, and zinc, and alloys such as brass. Precious metals such as gold, silver, and platinum and exotic or rare metals such as mercury, tungsten, beryllium, bismuth, cerium, cadmium, niobium, indium, gallium, germanium, lithium, selenium, tantalum, tellurium, vanadium, and zirconium are also non-ferrous. They are usually obtained through minerals such as sulfides, carbonates, and silicates. Non-ferrous metals are usually refined through electrolysis. | 0 | Metallurgy |
TRIM24 has been shown to interact with Mineralocorticoid receptor, TRIM33, Estrogen receptor alpha and Retinoid X receptor alpha. | 1 | Gene expression + Signal Transduction |
The Candelabro Trivulzio in the Milan Cathedral, a seven-branch bronze candlestick measuring 5 meters in height, has a base and lower part decorated with intricately designed ornament which is considered by many to be French work of the 13th century; the upper part with the branches was added in the second half of the 16th century. A portion of a similar object showing the same intricate decoration existed formerly at Reims, but was unfortunately destroyed during World War I.
In the 16th century the names of Germain Pilon and Jean Goujon are sufficient evidence of the ability to work in bronze. A great outburst of artistic energy is seen from the beginning of the 17th century, when works in ormolu or gilt bronze were produced in huge quantities. The craftsmanship is magnificent and of the highest quality, the designs at first refined and symmetrical; but later, under the influence of the rococo style, introduced in 1723, aiming only at gorgeous magnificence. It was all in keeping with the spirit of the age, and in their own sumptuous setting these fine candelabra, sconces, vases, clocks and rich mountings of furniture are entirely harmonious. The "ciseleur" and the "fondeur", such as Pierre Gouthière and Jacques Caffieri, associated themselves with the makers of fine furniture and of delicate Sèvres porcelain, the result being extreme richness and handsome effect. The style was succeeded after the French Revolution by a stiff, classical manner which, although having a charm of its own, lacks the life and freedom of earlier work. In London the styles may be studied in the Wallace collection, Manchester Square, and at the Victoria and Albert Museum, South Kensington; in New York at the Metropolitan Museum. | 0 | Metallurgy |
The lac repressor (LacI) operates by a helix-turn-helix motif in its DNA-binding domain, binding base-specifically to the major groove of the operator region of the lac operon, with base contacts also made by residues of symmetry-related alpha helices, the "hinge" helices, which bind deeply in the minor groove. This bound repressor can reduce transcription of the Lac proteins by occluding the RNA polymerase binding site or by prompting DNA looping. When lactose is present, allolactose binds to the lac repressor, causing an allosteric change in its shape. In its changed state, the lac repressor is unable to bind tightly to its cognate operator. Thus, the gene is mostly off in the absence of inducer and mostly on in the presence of inducer, although the degree of gene expression depends on the number of repressors in the cell and on the repressors DNA-binding affinity. Isopropyl β-D-1-thiogalactopyranoside (IPTG) is a commonly used allolactose mimic which can be used to induce transcription of genes being regulated by lac' repressor. | 1 | Gene expression + Signal Transduction |
ASF/SF2 is an SR protein, and as such, contains two functional modules: an arginine-serine rich region (RS domain), where the bulk of ASF/SF2 regulation takes place, and two RNA recognition motifs (RRMs), through which ASF/SF2 interacts with RNA and other splicing factors. These modules have different functions within general splicing factor function. | 1 | Gene expression + Signal Transduction |