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Carbon dioxide has unique long-term effects on climate change that are nearly "irreversible" for a thousand years after emissions stop (zero further emissions). The greenhouse gases methane and nitrous oxide do not persist over time in the same way as carbon dioxide. Even if human carbon dioxide emissions were to completely cease, atmospheric temperatures are not expected to decrease significantly in the short term. This is because the air temperature is determined by a balance between heating, due to greenhouse gases, and cooling due to heat transfer to the ocean. If emissions were to stop, CO levels and the heating effect would slowly decrease, but simultaneously the cooling due to heat transfer would diminish (because sea temperatures would get closer to the air temperature), with the result that the air temperature would decrease only slowly. Sea temperatures would continue to rise, causing thermal expansion and some sea level rise. Lowering global temperatures more rapidly would require carbon sequestration or geoengineering.
Various techniques have been proposed for removing excess carbon dioxide from the atmosphere. | 0 | Greenhouse Gases |
Resistance to fluoroquinolones is common in staphylococcus and pseudomonas. Resistance occurs in multiple ways. One mechanism is by an alteration in topoisomerase IV enzyme. A double mutant form of S. pneumoniae Gyr A + Par C bearing Ser-81-->Phe and Ser-79-->Phe mutations were eight to sixteen times less responsive to ciprofloxacin. | 1 | Enantiopure drugs |
Ampicillin is comparatively less toxic than other antibiotics, and side effects are more likely in those who are sensitive to penicillins and those with a history of asthma or allergies. In very rare cases, it causes severe side effects such as angioedema, anaphylaxis, and C. difficile infection (that can range from mild diarrhea to serious pseudomembranous colitis). Some develop black "furry" tongue. Serious adverse effects also include seizures and serum sickness. The most common side effects, experienced by about 10% of users are diarrhea and rash. Less common side effects can be nausea, vomiting, itching, and blood dyscrasias. The gastrointestinal effects, such as hairy tongue, nausea, vomiting, diarrhea, and colitis, are more common with the oral form of penicillin. Other conditions may develop up several weeks after treatment. | 1 | Enantiopure drugs |
Ampicillin is one of the most used drugs in pregnancy, and has been found to be generally harmless both by the Food and Drug Administration in the U.S. (which classified it as category B) and the Therapeutic Goods Administration in Australia (which classified it as category A). It is the drug of choice for treating Listeria monocytogenes in pregnant women, either alone or combined with an aminoglycoside. Pregnancy increases the clearance of ampicillin by up to 50%, and a higher dose is thus needed to reach therapeutic levels.
Ampicillin crosses the placenta and remains in the amniotic fluid at 50–100% of the concentration in maternal plasma; this can lead to high concentrations of ampicillin in the newborn.
While lactating mothers secrete some ampicillin into their breast milk, the amount is minimal.
In newborns, ampicillin has a longer half-life and lower plasma protein binding. The clearance by the kidneys is lower, as kidney function has not fully developed. | 1 | Enantiopure drugs |
Following oral administration of lisinopril, peak serum concentrations of lisinopril occur within about seven hours, although there was a trend to a small delay in time taken to reach peak serum concentrations in acute myocardial infarction patients. The peak effect of lisinopril is about 6 hours after administration for most people. Declining serum concentrations exhibit a prolonged terminal phase, which does not contribute to drug accumulation. This terminal phase probably represents saturable binding to ACE and is not proportional to dose. Lisinopril does not undergo metabolism and absorbed drug is excreted unchanged entirely in the urine. Based on urinary recovery, the mean extent of absorption of lisinopril is approximately 25% (reduced to 16% in people with New York Heart Association Functional Classification (NYHA) Class II–IV heart failure), with large interpatient variability (6 to 60%) at all doses tested (5 to 80 mg). Lisinopril absorption is not affected by the presence of food in the gastrointestinal tract.
Studies in rats indicate that lisinopril crosses the blood-brain barrier poorly. Multiple doses of lisinopril in rats result in little or no accumulation in brain tissue. | 1 | Enantiopure drugs |
Dextromethorphan (DXM) is a cough suppressant used in many cough and cold medicines. It affects serotonin, norepinephrine, NMDA, and sigma-1 receptors in the brain, all of which have been implicated in the pathophysiology of depression. In 2022, the FDA approved the combination dextromethorphan/bupropion to serve as a rapid acting antidepressant in patients with major depressive disorder.
It is in the morphinan class of medications with sedative, dissociative, and stimulant properties (at lower doses). Dextromethorphan does not have a significant affinity for the mu-opioid receptor activity typical of morphinan compounds and exerts its therapeutic effects through several other receptors. In its pure form, dextromethorphan occurs as a white powder.
When exceeding approved dosages, dextromethorphan acts as a dissociative hallucinogen. It has multiple mechanisms of action, including actions as a nonselective serotonin reuptake inhibitor and a sigma-1 receptor agonist. Dextromethorphan and its major metabolite, dextrorphan, also block the NMDA receptor at high doses, which produces effects similar to other dissociative anesthetics such as ketamine, nitrous oxide, and phencyclidine.
It was patented in 1949 and approved for medical use in 1953. | 1 | Enantiopure drugs |
The temperature and pressure at which ordinary solid, liquid, and gaseous water coexist in equilibrium is a triple point of water. Since 1954, this point had been used to define the base unit of temperature, the kelvin, but, starting in 2019, the kelvin is now defined using the Boltzmann constant, rather than the triple point of water.
Due to the existence of many polymorphs (forms) of ice, water has other triple points, which have either three polymorphs of ice or two polymorphs of ice and liquid in equilibrium. Gustav Heinrich Johann Apollon Tammann in Göttingen produced data on several other triple points in the early 20th century. Kamb and others documented further triple points in the 1960s. | 0 | Greenhouse Gases |
Single 20 to 40mg oral doses generally give rise to peak plasma esomeprazole concentrations of 0.5-1.0mg/L within 1–4 hours, but after several days of once-daily administration, these levels may increase by about 50%. A 30-minute intravenous infusion of a similar dose usually produces peak plasma levels on the order of 1–3mg/L. The drug is rapidly cleared from the body, largely by urinary excretion of pharmacologically inactive metabolites such as 5-hydroxymethylesomeprazole and 5-carboxyesomeprazole. Esomeprazole and its metabolites are analytically indistinguishable from omeprazole and the corresponding omeprazole metabolites unless chiral techniques are employed. | 1 | Enantiopure drugs |
Zuclopenthixol (brand names Cisordinol, Clopixol and others), also known as zuclopentixol, is a medication used to treat schizophrenia and other psychoses. It is classed, pharmacologically, as a typical antipsychotic. Chemically it is a thioxanthene. It is the cis-isomer of clopenthixol (Sordinol, Ciatyl). Clopenthixol was introduced in 1961, while zuclopenthixol was introduced in 1978.
Zuclopenthixol is a D and D antagonist, α-adrenergic and 5-HT antagonist. While it is approved for use in Australia, Canada, Ireland, India, New Zealand, Singapore, South Africa and the UK it is not approved for use in the United States. | 1 | Enantiopure drugs |
1,1,1,2-Tetrafluoroethane is also being considered as an organic solvent, both in liquid and supercritical fluid.
It is used in the resistive plate chamber particle detectors in the Large Hadron Collider. It is also used for other types of particle detectors, e.g. some cryogenic particle detectors. It can be used as an alternative to sulfur hexafluoride in magnesium smelting as a shielding gas. | 0 | Greenhouse Gases |
Cefalexin is the International Nonproprietary Name (INN) and the Australian Approved Name (AAN), while cephalexin is the British Approved Name (BAN) and the United States Adopted Name (USAN). Brand names for cefalexin include Keflex, Acfex, Cephalex, Ceporex, L-Xahl, Medoxine, Ospexin, Torlasporin, Bio-Cef, Panixine DisperDose, and Novo-Lexin. | 1 | Enantiopure drugs |
-Deprenyl, also known as or dextro-N-propargyl-N-methylamphetamine, is an MAO-B inhibitor that metabolizes into -amphetamine and -methamphetamine and is therefore also a norepinephrine–dopamine releasing agent. It is the opposite enantiomer of -deprenyl (selegiline).
-Deprenyl, also an MAO-B inhibitor, metabolizes to -amphetamine and -methamphetamine, which are both norepinephrine releasing agents. In contrast, -deprenyl additionally has dopaminergic effects and has been found to be reinforcing in scientific research, whereas -deprenyl is not known to have any appreciable psychological reinforcement.
In addition to its actions as an MAO-B inhibitor and NDRA, -deprenyl has been found to bind with high affinity to the σ receptor (K = 79 nM) similarly to various other amphetamine derivatives. Its -isomer, selegiline, binds with 3.5-fold lower affinity in comparison. | 1 | Enantiopure drugs |
The CO fertilization effect or carbon fertilization effect causes an increased rate of photosynthesis while limiting leaf transpiration in plants. Both processes result from increased levels of atmospheric carbon dioxide (CO). The carbon fertilization effect varies depending on plant species, air and soil temperature, and availability of water and nutrients. Net primary productivity (NPP) might positively respond to the carbon fertilization effect. Although, evidence shows that enhanced rates of photosynthesis in plants due to CO fertilization do not directly enhance all plant growth, and thus carbon storage. The carbon fertilization effect has been reported to be the cause of 44% of gross primary productivity (GPP) increase since the 2000s. Earth System Models, Land System Models and Dynamic Global Vegetation Models are used to investigate and interpret vegetation trends related to increasing levels of atmospheric CO. However, the ecosystem processes associated with the CO fertilization effect remain uncertain and therefore are challenging to model.
Terrestrial ecosystems have reduced atmospheric CO concentrations and have partially mitigated climate change effects. The response by plants to the carbon fertilization effect is unlikely to significantly reduce atmospheric CO concentration over the next century due to the increasing anthropogenic influences on atmospheric CO. Earth's vegetated lands have shown significant greening since the early 1980s largely due to rising levels of atmospheric CO.
Theory predicts the tropics to have the largest uptake due to the carbon fertilization effect, but this has not been observed. The amount of uptake from fertilization also depends on how forests respond to climate change, and if they are protected from deforestation.
Changes in atmospheric carbon dioxide may reduce the nutritional quality of some crops, with for instance wheat having less protein and less of some minerals. Food crops could see a reduction of protein, iron and zinc content in common food crops of 3 to 17%. | 0 | Greenhouse Gases |
The chiral switch concept is illustrated in the diagram. This chiral switch is from (±)-ibuprofen to (S)-(+)-ibuprofen (dexibuprofen). The nonsteroidal anti-inflammatory drug (NSAID) ibuprofen was the first chiral drug of the NSAID class to be switched to the single-enantiomer version in 1994. The switch was done based on the fact that the (S)-ibuprofen, the eutomer, was over 100-fold more potent as an inhibitor of cycloxygenase-1 (COX-1) enzyme than (R)-ibuprofen. Moreover, ibuprofen, when administered as the racemate, the active (R)-enantiomer undergoes partial unidirectional chiral inversion (approximately 60%) to the (S)-enantiomer. Therefore, the use of the single (S)-ibuprofen was expected to give faster onset of action at a lower dosage. Further, while choosing the chiral drug candidate for a chiral switch one should take a look at the chiral inversion tendency of the molecule. For instance, thalidomide, the sedative drug, undergoes bidirectional chiral inversion or racemization in biological systems. In such cases chiral switching efforts will be pointless. | 1 | Enantiopure drugs |
Evekeo is an FDA-approved medication that contains racemic amphetamine sulfate (i.e., 50% levoamphetamine sulfate and 50% dextroamphetamine sulfate). It is approved for the treatment of narcolepsy, ADHD, and exogenous obesity. The orally disintegrating tablets are approved for the treatment of attention deficit hyperactivity disorder (ADHD) in children and adolescents aged six to 17 years of age. | 1 | Enantiopure drugs |
Alacepril (INN) is an ACE inhibitor medication indicated as a treatment for hypertension. The medication metabolizes to captopril and desacetylalacepril. Alacepril is primarily used to treat hypertension, and in some cases, renovascular hypertension. It's often combined with other medications, particularly other blood pressure lowering classes of medications like thiazide diuretics to maximize its effectiveness. | 1 | Enantiopure drugs |
Flutamide has been researched and used extensively in the treatment of androgen-dependent skin and hair conditions in women including acne, seborrhea, hirsutism, and scalp hair loss, as well as in hyperandrogenism (e.g., in polycystic ovary syndrome or congenital adrenal hyperplasia), and is effective in improving the symptoms of these conditions. The dosages used are lower than those used in the treatment of prostate cancer. Although flutamide continues to be used for these indications, its use in recent years has been limited due to the risk of potentially fatal hepatotoxicity, and it is no longer recommended as a first- or second-line therapy. The related NSAA bicalutamide has also been found to be effective in the treatment of hirsutism in women and appears to have comparable effectiveness to that of flutamide, but has a far lower and only small risk of hepatotoxicity in comparison.
Aside from its risk of liver toxicity and besides other nonsteroidal antiandrogens, it has been said that flutamide is likely the best typically used antiandrogen medication for the treatment of androgen-dependent symptoms in women. This is related to its high effectiveness and minimal side effects. | 1 | Enantiopure drugs |
The development of the fluorocarbon industry coincided with World War II. Prior to that, fluorocarbons were prepared by reaction of fluorine with the hydrocarbon, i.e., direct fluorination. Because C-C bonds are readily cleaved by fluorine, direct fluorination mainly affords smaller perfluorocarbons, such as tetrafluoromethane, hexafluoroethane, and octafluoropropane. | 0 | Greenhouse Gases |
HFCs were developed in the 1990s to substitute for substances such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). As these substances were found to deplete the ozone layer, the Montreal Protocol began to lay down provisions for them to be phased-out globally after the agreement was ratified in 1987.
PFCs and SF were already in use prior to the Montreal Protocol.
NF use has grown since the 1990s along with the rapid expansion of the microelectronics fabrication industry. | 0 | Greenhouse Gases |
Many lawsuits have been filed against Bayer, the manufacturer of drospirenone, due to the higher risk of venous thromboembolism (VTE) that has been observed with combined birth control pills containing drospirenone and certain other progestins relative to the risk with levonorgestrel-containing combined birth control pills.
In July 2012, Bayer notified its stockholders that there were more than 12,000 such lawsuits against the company involving Yaz, Yasmin, and other birth control pills with drospirenone. They also noted that the company by then had settled 1,977 cases for US$402.6 million, for an average of US$212,000 per case, while setting aside US$610.5 million to settle the others.
As of 17 July 2015, there have been at least 4,000 lawsuits and claims still pending regarding VTE related to drospirenone. This is in addition to around 10,000 claims that Bayer has already settled without admitting liability. These claims of VTE have amounted to US$1.97 billion. Bayer also reached a settlement for arterial thromboembolic events, including stroke and heart attacks, for US$56.9 million. | 1 | Enantiopure drugs |
For many years scientists in drug development have been blind to the three-dimensional consequences of stereochemistry, chiefly due to the lack of technology for making enantioselective investigations. Besides the thalidomide tragedy, another event that raised the importance of issues of stereochemistry in drug research and development was the publication of a manuscript in 1984 entitled, "Stereochemistry, a basis of sophisticated nonsense in pharmacokinetics and clinical pharmacology" by Ariëns. This article, and the series of articles that followed, criticized the practice of conducting pharmacokinetic and pharmacodynamic studies on racemic drugs and ignoring the separate contributions of the individual enantiomers. These papers have served to crystallize some of the important issues surrounding racemic drugs and stimulated much discussion in industry, government and academia. | 1 | Enantiopure drugs |
Drug repurposing and chiral switches are part of the secondary pharmaceuticals strategy. The COVID-19 pandemic has increased drug repurposing and this approach suggests combining the two strategies for better results. This combination strategy is not new, but has not been intentional until now. The combination strategy may improve pharmacology, patents, reduce costs, speed up approval times, and increase regulatory exclusivities. The benefits of the combination strategy include superior pharmacology, stronger patents, shorter approval times, and more exclusivity. Patenting this combination strategy is not considered evergreening, product hopping, or me-too. This perspective calls for a comprehensive search for worldwide-approved racemic drugs to be repurposed and combined with chiral switches. | 1 | Enantiopure drugs |
In one of the syntheses, 7-aminocephalosporanic acid (7-ACA) is reacted with bromoacetyl chloride to give the amide. The halo group is then displaced by 4-thiopyridine. | 1 | Enantiopure drugs |
Tetrafluoroethane is typically made by reacting trichloroethylene with hydrogen fluoride:
:CHCl=CCl + 4 HF → CFCHF + 3 HCl
It reacts with butyllithium to give trifluorovinyl lithium:
:CFCHF + 2 BuLi → CF=CFLi + LiF + 2 BuH | 0 | Greenhouse Gases |
As they are inert, perfluoroalkanes have essentially no chemical uses, but their physical properties have led to their use in many diverse applications. These include:
*Perfluorocarbon tracer
*Liquid dielectric
*Chemical vapor deposition
*Organic Rankine cycle
*Fluorous biphasic catalysis
*Cosmetics
*Ski waxes
As well as several medical uses:
*Contrast-enhanced ultrasound
*Oxygen Therapeutics
*Blood substitute
*Liquid breathing
*Eye surgery
*Tattoo removal | 0 | Greenhouse Gases |
Diarrhea is more common and sometimes more severe with flutamide than with other NSAAs. In a comparative trial of combined androgen blockade for prostate cancer, the rate of diarrhea was 26% for flutamide and 12% for bicalutamide. Moreover, 6% of flutamide-treated patients discontinued the medication due to diarrhea, whereas only 0.5% of bicalutamide-treated patients did so. In the case of antiandrogen monotherapy for prostate cancer, the rates of diarrhea are 5 to 20% for flutamide, 2 to 5% for bicalutamide, and 2 to 4% for nilutamide. In contrast to diarrhea, the rates of nausea and vomiting are similar among the three medications. | 1 | Enantiopure drugs |
Due to its high relative density, it gathers in low-lying areas, and at high concentrations it can cause asphyxiation. Other health effects are similar to tetrafluoromethane. | 0 | Greenhouse Gases |
Grewe's cyclization is easier to handle in terms of the chemicals used, produces higher yields and higher purity of the product. | 1 | Enantiopure drugs |
There are several surface measurement (including flasks and continuous in situ) networks including NOAA/ERSL, WDCGG, and RAMCES. The NOAA/ESRL Baseline Observatory Network, and the Scripps Institution of Oceanography Network data are hosted at the CDIAC at ORNL. The World Data Centre for Greenhouse Gases (WDCGG), part of GAW, data are hosted by the JMA. The Reseau Atmospherique de Mesure des Composes an Effet de Serre database (RAMCES) is part of IPSL.
From these measurements, further products are made which integrate data from the various sources. These products also address issues such as data discontinuity and sparseness. GLOBALVIEW- is one of these products.
Ongoing ground-based total column measurements began more recently. Column measurements typically refer to an averaged column amount denoted X, rather than a surface only measurement. These measurements are made by the TCCON. These data are also hosted on the CDIAC, and made publicly available according to the data use policy. | 0 | Greenhouse Gases |
Although not as toxic as many similar compounds, inhaled or ingested 1,1,1-trichloroethane does act as a central nervous system depressant and can cause effects similar to those of ethanol intoxication, including dizziness, confusion, and, in sufficiently high concentrations, unconsciousness and death. Fatal poisonings and illnesses linked to intentional inhalation of trichloroethane have been reported. The removal of the chemical from correction fluid commenced due to Proposition 65 declaring it hazardous and toxic.
Prolonged skin contact with the liquid can result in the removal of fats from the skin, resulting in skin irritation.
The International Agency for Research on Cancer places 1,1,1-trichloroethane in Group 2A as a probable carcinogen. | 0 | Greenhouse Gases |
It is branded as Dynorm, Inhibace, Vascace and many other names in various countries. None of these are available in the United States as of May 2010. | 1 | Enantiopure drugs |
While new production of these refrigerants has been banned, large volumes still exist in older systems and have been said to pose an immediate threat to our environment. Preventing the release of these harmful refrigerants has been ranked as one of the single most effective actions we can take to mitigate catastrophic climate change. | 0 | Greenhouse Gases |
Perfluoroalkanes are very stable because of the strength of the carbon–fluorine bond, one of the strongest in organic chemistry.
Its strength is a result of the electronegativity of fluorine imparting partial ionic character through partial charges on the carbon and fluorine atoms, which shorten and strengthen the bond (compared to carbon-hydrogen bonds) through favorable covalent interactions. Additionally, multiple carbon–fluorine bonds increase the strength and stability of other nearby carbon–fluorine bonds on the same geminal carbon, as the carbon has a higher positive partial charge. Furthermore, multiple carbon–fluorine bonds also strengthen the "skeletal" carbon–carbon bonds from the inductive effect. Therefore, saturated fluorocarbons are more chemically and thermally stable than their corresponding hydrocarbon counterparts, and indeed any other organic compound. They are susceptible to attack by very strong reductants, e.g. Birch reduction and very specialized organometallic complexes.
Fluorocarbons are colorless and have high density, up to over twice that of water. They are not miscible with most organic solvents (e.g., ethanol, acetone, ethyl acetate, and chloroform), but are miscible with some hydrocarbons (e.g., hexane in some cases). They have very low solubility in water, and water has a very low solubility in them (on the order of 10 ppm). They have low refractive indices.
As the high electronegativity of fluorine reduces the polarizability of the atom, fluorocarbons are only weakly susceptible to the fleeting dipoles that form the basis of the London dispersion force. As a result, fluorocarbons have low intermolecular attractive forces and are lipophobic in addition to being hydrophobic and non-polar. Reflecting the weak intermolecular forces these compounds exhibit low viscosities when compared to liquids of similar boiling points, low surface tension and low heats of vaporization. The low attractive forces in fluorocarbon liquids make them compressible (low bulk modulus) and able to dissolve gas relatively well. Smaller fluorocarbons are extremely volatile. There are five perfluoroalkane gases: tetrafluoromethane (bp −128 °C), hexafluoroethane (bp −78.2 °C), octafluoropropane (bp −36.5 °C), perfluoro-n-butane (bp −2.2 °C) and perfluoro-iso-butane (bp −1 °C). Nearly all other fluoroalkanes are liquids; the most notable exception is perfluorocyclohexane, which sublimes at 51 °C. Fluorocarbons also have low surface energies and high dielectric strengths. | 0 | Greenhouse Gases |
Amoxicillin was one of several semisynthetic derivatives of 6-aminopenicillanic acid (6-APA) developed by the Beecham Group in the 1960s. It was invented by Anthony Alfred Walter Long and John Herbert Charles Nayler, two British scientists. It became available in 1972 and was the second aminopenicillin to reach the market (after ampicillin in 1961). Co-amoxiclav became available in 1981. | 1 | Enantiopure drugs |
Levonorgestrel stimulates the proliferation of MCF-7 breast cancer cells in vitro, an action that is independent of the classical PRs and is instead mediated via the progesterone receptor membrane component-1 (PGRMC1). Certain other progestins act similarly in this assay, whereas progesterone acts neutrally. It is unclear if these findings may explain the different risks of breast cancer observed with progesterone and progestins in clinical studies. | 1 | Enantiopure drugs |
Contraindications are hypersensitivity against ACE inhibitors, especially if it has resulted in angioedema; idiopathic or hereditary angioedema; kidney failure; the second and third trimesters in pregnancy; and combination with the drug aliskiren in people with diabetes. | 1 | Enantiopure drugs |
According to the FDA, the stereoisomeric composition of a chiral drug should be known, and its effects should be well-characterized from pharmacologic, toxicologic, and clinical standpoints. In order to profile the different stereoisomers of enantiopure drugs, manufacturers are urged to develop quantitative assays for individual enantiomers in in vivo samples early in the development stage.
Ideally, the main pharmacologic activities of the isomers should be compared in in vitro systems in animals. During instances when toxic findings are present beyond the natural extensions of the pharmacologic effects of the drug, toxicologic evaluation of the individual isomers in question must be completed. | 1 | Enantiopure drugs |
There is evidence for high concentrations of over 6,000 ppm between 600 and 400 million years ago, and of over 3,000 ppm between 200 and 150 million years ago.
Indeed, higher CO concentrations are thought to have prevailed throughout most of the Phanerozoic Eon, with concentrations four to six times current concentrations during the Mesozoic era, and ten to fifteen times current concentrations during the early Palaeozoic era until the middle of the Devonian period, about 400 million years ago. The spread of land plants is thought to have reduced CO concentrations during the late Devonian, and plant activities as both sources and sinks of CO have since been important in providing stabilizing feedbacks.
Earlier still, a 200-million year period of intermittent, widespread glaciation extending close to the equator (Snowball Earth) appears to have been ended suddenly, about 550 Ma, by a colossal volcanic outgassing that raised the concentration of the atmosphere abruptly to 12%, about 350 times modern levels, causing extreme greenhouse conditions and carbonate deposition as limestone at the rate of about 1 mm per day. This episode marked the close of the Precambrian Eon, and was succeeded by the generally warmer conditions of the Phanerozoic, during which multicellular animal and plant life evolved. No volcanic CO emission of comparable scale has occurred since. In the modern era, emissions to the atmosphere from volcanoes are approximately 0.645 billion tons of per year, whereas humans contribute 29 billion tons of each year. | 0 | Greenhouse Gases |
Levoketoconazole, sold under the brand name Recorlev, is a steroidogenesis inhibitor that is used for the treatment of Cushing's syndrome. Levoketoconazole was approved for medical use in the United States in December 2021.
Levoketoconazole is the levorotatory or (2S,4R) enantiomer of ketoconazole, and it is an inhibitor of the enzymes CYP11B1 (11β-hydroxylase), CYP17A1 (17α-hydroxylase/17,20-lyase), and CYP21A2 (21-hydroxylase). It inhibits glucocorticoid biosynthesis and hence circulating levels of glucocorticoids, thereby treating Cushing's syndrome. In addition to its increased potency, the drug is 12-fold less potent than racemic ketoconazole in inhibiting CYP7A1 (cholesterol 7α-hydroxylase), theoretically resulting in further reduced interference with bile acid production and metabolite elimination and therefore less risk of hepatotoxicity. Levoketoconazole has also been found to inhibit CYP11A1 (cholesterol side-chain cleavage enzyme) and CYP51A1 (lanosterol-14α-demethylase), similarly but more potently relative to ketoconazole. | 1 | Enantiopure drugs |
Persons with certain genetic variations in human leukocyte antigens (HLAs) are under increased risk of developing skin reactions such as acute generalized exanthematous pustulosis (AGEP), but also severe ones such as Stevens–Johnson and DRESS syndrome, under treatment with carbamazepine and drugs with related chemical structures. This is true for the HLA-A*3101 allele, which occurs in 2 to 5% of Europeans and 10% of Japanese people, and the HLA-B*1502 allele, which is mainly found in people of Asian descent. Theoretically, this may also apply to ESL. | 1 | Enantiopure drugs |
Levofloxacin is not approved in most countries for the treatment of children except in unique and life-threatening infections because it is associated with an elevated risk of musculoskeletal injury in this population, a property it shares with other fluoroquinolones.
In the United States levofloxacin is approved for the treatment of anthrax and plague in children over six months of age.
Levofloxacin is recommended by the Pediatric Infectious Disease Society and the Infectious Disease Society of America as a first-line treatment for pediatric pneumonia caused by penicillin-resistant Streptococcus pneumoniae, and as a second-line agent for the treatment of penicillin-sensitive cases.
In one study, 1534 juvenile patients (age 6 months to 16 years) treated with levofloxacin as part of three efficacy trials were followed up to assess all musculoskeletal events occurring up to 12 months post-treatment. At 12 months follow-up the cumulative incidence of musculoskeletal adverse events was 3.4%, compared to 1.8% among 893 patients treated with other antibiotics. In the levafloxacin-treated group, approximately two-thirds of these musculoskeletal adverse events occurred in the first 60 days, 86% were mild, 17% were moderate, and all resolved without long-term sequelae. | 1 | Enantiopure drugs |
Cefuroxime is generally well tolerated, and its side effects are usually transient. If ingested after food, this antibiotic is both better absorbed and less likely to cause its most common side effects of diarrhea, nausea, vomiting, headaches/migraines, dizziness, and abdominal pain compared to most antibiotics in its class.
Although a widely stated cross-allergic risk of about 10% exists between cephalosporins and penicillin, an assessment in 2006 have shown no increased risk for a cross-allergic reaction for cefuroxime and several other second-generation or later cephalosporins. | 1 | Enantiopure drugs |
ACE inhibitors inhibit the actions of angiotensin converting enzyme (ACE), thereby lowering the production of angiotensin II and decreasing the breakdown of bradykinin. The decrease in angiotensin II results in relaxation of arteriole smooth muscle leading to a decrease in total peripheral resistance, reducing blood pressure as the blood is pumped through widened vessels. Its effect on bradykinin is responsible for the dry cough side effect.
Ramipril, a prodrug or precursor drug, is converted to the active metabolite ramiprilat by carboxylesterase 1. Ramiprilat is mostly excreted by the kidneys. Its half-life is variable (3–16 hours), and is prolonged by heart and liver failure, as well as kidney failure. Peak effect occurs between 3 and 6 hours after dosing, with approximately 50% of this effect retained after 24 hours. | 1 | Enantiopure drugs |
Carbon tetrachloride, also known by many other names (such as carbon tet for short and tetrachloromethane, also recognised by the IUPAC) is a chemical compound with the chemical formula CCl. It is a non-flammable, dense, colourless liquid with a "sweet" chloroform-like odour that can be detected at low levels. It was formerly widely used in fire extinguishers, as a precursor to refrigerants and as a cleaning agent, but has since been phased out because of environmental and safety concerns. Exposure to high concentrations of carbon tetrachloride can affect the central nervous system and degenerate the liver and kidneys. Prolonged exposure can be fatal.
Tradenames include: Carbon-Tet, Katharin (Germany, 1890s), Benzinoform, Carbona and Thawpit in the cleaning industry, Halon-104 in firefighting, Refrigerant-10 in HVACR, and Necatorina and Seretin as a medication. | 0 | Greenhouse Gases |
Dicloxacillin is commercially available as the sodium salt, dicloxacillin sodium, in capsules and as a powder for reconstitution. | 1 | Enantiopure drugs |
Adverse effects of drospirenone alone occurring in more than 1% of women may include unscheduled menstrual bleeding (breakthrough or intracyclic) (40.3–64.4%), acne (3.8%), metrorrhagia (2.8%), headache (2.7%), breast pain (2.2%), weight gain (1.9%), dysmenorrhea (1.9%), nausea (1.8%), vaginal hemorrhage (1.7%), decreased libido (1.3%), breast tenderness (1.2%), and irregular menstruation (1.2%). | 1 | Enantiopure drugs |
In 2010, AstraZeneca announced a co-promotion agreement with Daiichi Sankyo to distribute Nexium in Japan. In September 2011, Nexium was approved for sale and was launched by Daiichi Sankyo in Japan. Esomeprazole was approved for use in the United States in February 2001. | 1 | Enantiopure drugs |
Water has an unusually high surface tension of 71.99 mN/m at 25 °C which is caused by the strength of the hydrogen bonding between water molecules. This allows insects to walk on water. | 0 | Greenhouse Gases |
In veterinary medicine, selegiline is sold under the brand name Anipryl (manufactured by Zoetis). It is used in dogs to treat canine cognitive dysfunction and, at higher doses, pituitary-dependent hyperadrenocorticism (PDH). Canine cognitive dysfunction is a form of dementia that mimics Alzheimer's disease in humans. Geriatric dogs treated with selegiline show improvements in sleeping pattern, reduced incontinence, and increased activity level; most show improvements by one month. Though it is labeled for dog use only, selegiline has been used off-label for geriatric cats with cognitive dysfunction.
Selegiline's efficacy in treating pituitary-dependent hyperadrenocorticism has been disputed. Theoretically, it works by increasing dopamine levels, which downregulates the release of ACTH, eventually leading to reduced levels of cortisol. Some claim that selegiline is only effective at treating PDH caused by lesions in the anterior pituitary (which comprise most canine cases). The greatest sign of improvement is lessening of abdominal distention.
Side effects in dogs are uncommon, but they include vomiting, diarrhea, diminished hearing, salivation, decreased weight and behavioral changes such as hyperactivity, listlessness, disorientation, and repetitive motions.
Selegiline does not appear to have a clinical effect on horses. | 1 | Enantiopure drugs |
The pharmacology of dextrorphan is similar to that of dextromethorphan (DXM). However, dextrorphan is much more potent as an NMDA receptor antagonist as well much less active as a serotonin reuptake inhibitor, but retains DXM's activity as a norepinephrine reuptake inhibitor.
It also has more affinity for the opioid receptors than dextromethorphan, significantly so at high doses. | 1 | Enantiopure drugs |
Levosulpiride, sold under the brand name SULPEPTA , is a potent prokinetic agent of the benzamide class. It is a selective antagonist of the dopamine D receptors and 5HT4 Agonism on both central and peripheral nervous systems. Levosulpiride is claimed to have mood elevating properties.
Chemically, it is the (S)-(−)-enantiomer of sulpiride. | 1 | Enantiopure drugs |
Escitalopram, sold under the brand names Lexapro and Cipralex, among others, is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. Escitalopram is mainly used to treat major depressive disorder and generalized anxiety disorder. It is taken by mouth, available commercially as an oxalate salt exclusively.
Common side effects include trouble sleeping, nausea, sexual problems, and feeling tired. More serious side effects may include suicidal thoughts in people up to the age of 24 years. It is unclear if use during pregnancy or breastfeeding is safe. Escitalopram is the (S)-enantiomer of citalopram (which exists as a racemate), hence the name es-citalopram.
Escitalopram was approved for medical use in the United States in 2002. Escitalopram is rarely replaced by twice the dose of citalopram, though escitalopram is safer and more effective. It is on the World Health Organization's List of Essential Medicines. In 2021, it was the fifteenth most commonly prescribed medication in the United States, with more than 30million prescriptions. | 1 | Enantiopure drugs |
A chemical synthesis of captopril by treatment of -proline with (2S)-3-acetylthio-2-methylpropanoyl chloride under basic conditions (NaOH), followed by aminolysis of the protective acetyl group to unmask the drug's free thiol, is depicted in the figure at right.
Procedure 2 taken out of patent US4105776. See examples 28, 29a and 36. | 1 | Enantiopure drugs |
Pseudoephedrine is a sympathomimetic amine. Its principal mechanism of action relies on its direct action on the adrenergic receptor system. The vasoconstriction that pseudoephedrine produces is believed to be principally an α-adrenergic receptor response.
Pseudoephedrine acts on α- and β2-adrenergic receptors, to cause vasoconstriction and relaxation of smooth muscle in the bronchi, respectively. α-Adrenergic receptors are located on the muscles lining the walls of blood vessels. When these receptors are activated, the muscles contract, causing the blood vessels to constrict (vasoconstriction). The constricted blood vessels now allow less fluid to leave the blood vessels and enter the nose, throat, and sinus linings, which results in decreased inflammation of nasal membranes, as well as decreased mucus production. Thus, by constriction of blood vessels, mainly those located in the nasal passages, pseudoephedrine causes a decrease in the symptoms of nasal congestion. Activation of β2-adrenergic receptors produces relaxation of smooth muscle of the bronchi, causing bronchial dilation and in turn decreasing congestion (although not fluid) and difficulty breathing. | 1 | Enantiopure drugs |
Rasagiline is broken down via CYP1A2, part of the cytochrome P450 metabolic path in the liver. It is contraindicated in patients with hepatic insufficiency and its use should be monitored carefully in patients taking other drugs that alter the normal effectiveness of this metabolic path. | 1 | Enantiopure drugs |
Despite having a lower than optimum drug penetration into bone ratio of 10–20%, flucloxacillin appears effective in treating osteomyelitis.
Depending on local guidance it may be used in the treatment of infection of joints while waiting for culture results. | 1 | Enantiopure drugs |
As an ACE inhibitor, moexipril causes a decrease in ACE. This blocks the conversion of angiotensin I to angiotensin II. Blockage of angiotensin II limits hypertension within the vasculature. Additionally, moexipril has been found to possess cardioprotective properties. Rats given moexipril one week prior to induction of myocardial infarction, displayed decreased infarct size. The cardioprotective effects of ACE inhibitors are mediated through a combination of angiotensin II inhibition and bradykinin proliferation. Increased levels of bradykinin stimulate in the production of prostaglandin E and nitric oxide, which cause vasodilation and continue to exert antiproliferative effects. Inhibition of angiotensin II by moexipril decreases remodeling effects on the cardiovascular system. Indirectly, angiotensin II stimulates of the production of endothelin 1 and 3 (ET1, ET3) and the transforming growth factor beta-1 (TGF-β1), all of which have tissue proliferative effects that are blocked by the actions of moexipril. The antiproliferative effects of moexipril have also been demonstrated by in vitro studies where moexipril inhibits the estrogen-stimulated growth of neonatal cardiac fibroblasts in rats. Other ACE inhibitors have also been found to produce these actions, as well. | 1 | Enantiopure drugs |
Pseudoephedrine may be quantified in blood, plasma, or urine to monitor any possible performance-enhancing use by athletes, confirm a diagnosis of poisoning, or to assist in a medicolegal death investigation. Some commercial immunoassay screening tests directed at the amphetamines cross-react appreciably with pseudoephedrine, but chromatographic techniques can easily distinguish pseudoephedrine from other phenethylamine derivatives. Blood or plasma pseudoephedrine concentrations are typically in the 50–300 µg/L range in persons taking the drug therapeutically, 500–3000 µg/L in people with substance use disorder involving pseudoephedrine, or poisoned patients and 10–70 mg/L in cases of acute fatal overdose. | 1 | Enantiopure drugs |
Perfluorotributylamine (PFTBA), also referred to as FC43, is an organic compound with the chemical formula . It is a colorless liquid. A molecule of this chemical compound consists of three butyl groups connected to one nitrogen atom, in which all of the hydrogen atoms are replaced with fluorine atoms. The compound is produced for the electronics industry, along with other perfluoroalkylamines. The high degree of fluorination significantly reduces the basicity of the central amine due to electron-withdrawing effects. | 0 | Greenhouse Gases |
Piperacillin is a broad-spectrum β-lactam antibiotic of the ureidopenicillin class. The chemical structure of piperacillin and other ureidopenicillins incorporates a polar side chain that enhances penetration into Gram-negative bacteria and reduces susceptibility to cleavage by Gram-negative beta lactamase enzymes. These properties confer activity against the important hospital pathogen Pseudomonas aeruginosa. Thus piperacillin is sometimes referred to as an "anti-pseudomonal penicillin".
When used alone, piperacillin lacks strong activity against the Gram-positive pathogens such as Staphylococcus aureus, as the beta-lactam ring is hydrolyzed by the bacteria's beta-lactamase.
It was patented in 1974 and approved for medical use in 1981. Piperacillin is most commonly used in combination with the beta-lactamase inhibitor tazobactam (piperacillin/tazobactam), which enhances piperacillin's effectiveness by inhibiting many beta lactamases to which it is susceptible. However, the co-administration of tazobactam does not confer activity against MRSA, as penicillin (and most other beta lactams) do not avidly bind to the penicillin-binding proteins of this pathogen. The World Health Organization classifies piperacillin as critically important for human medicine. | 1 | Enantiopure drugs |
Common side effects include headache, diarrhea, nausea, flatulence, decreased appetite, constipation, dry mouth, and abdominal pain. More severe side effects are severe allergic reactions, chest pain, dark urine, fast heartbeat, fever, paresthesia, persistent sore throat, severe stomach pain, unusual bruising or bleeding, unusual tiredness, and yellowing of the eyes or skin.
Proton pump inhibitors may be associated with a greater risk of hip fractures and Clostridium difficile-associated diarrhoea. Patients are frequently administered the drugs in intensive care as a protective measure against ulcers, but this use is also associated with a 30% increase in occurrence of pneumonia.
Long-term use of proton pump inhibitors in patients treated for Helicobacter pylori has been shown to dramatically increase the risk of gastric cancer.
Acute tubulointerstitial nephritis is a possible adverse reaction when using proton pump inhibitors. | 1 | Enantiopure drugs |
LAAM is indicated as a second-line treatment for the treatment and management of opioid dependence if patients fail to respond to drugs like methadone or buprenorphine.
LAAM is used as an oral solution of LAAM hydrochloride at a concentration of 10 mg/mL in bottles of 120 and 500 mL under the brand name Orlaam. The first dose of LAAM for patients who have not started treatment with methadone is 20–40 mg. The first dose for patients who have been receiving methadone will be a little higher than the amount of methadone that was being taken every day, but not more than 120 mg. Afterwards, the dosage may be adjusted as needed. Unlike methadone, which requires daily administration, LAAM is administered two to three times a week. | 1 | Enantiopure drugs |
Normally, angiotensin I is converted to angiotensin II by an angiotensin-converting enzyme (ACE). Angiotensin II constricts blood vessels, increasing blood pressure. Enalaprilat, the active metabolite of enalapril, inhibits ACE. Inhibition of ACE decreases levels of angiotensin II, leading to less vasoconstriction and decreased blood pressure. | 1 | Enantiopure drugs |
Ampicillin is used to treat infections by many gram-positive and gram-negative bacteria. It was the first "broad spectrum" penicillin with activity against gram-positive bacteria, including Streptococcus pneumoniae, Streptococcus pyogenes, some isolates of Staphylococcus aureus (but not penicillin-resistant or methicillin-resistant strains), Trueperella, and some Enterococcus. It is one of the few antibiotics that works against multidrug resistant Enterococcus faecalis and E. faecium. Activity against gram-negative bacteria includes Neisseria meningitidis, some Haemophilus influenzae, and some of the Enterobacteriaceae (though most Enterobacteriaceae and Pseudomonas are resistant). Its spectrum of activity is enhanced by co-administration of sulbactam, a drug that inhibits beta lactamase, an enzyme produced by bacteria to inactivate ampicillin and related antibiotics. It is sometimes used in combination with other antibiotics that have different mechanisms of action, like vancomycin, linezolid, daptomycin, and tigecycline. | 1 | Enantiopure drugs |
Lisinopril is an ACE inhibitor, meaning it blocks the actions of angiotensin-converting enzyme (ACE) in the renin–angiotensin–aldosterone system (RAAS), preventing angiotensin I from being converted to angiotensin II. Angiotensin II is a potent direct vasoconstrictor and a stimulator of aldosterone release. Reduction in the amount of angiotensin II results in relaxation of the arterioles. Reduction in the amount of angiotensin II also reduces the release of aldosterone from the adrenal cortex, which allows the kidney to excrete sodium along with water into the urine, and increases retention of potassium ions. Specifically, this process occurs in the peritubular capillaries of the kidneys in response to a change in Starling forces. The inhibition of the RAAS system causes an overall decrease in blood pressure. | 1 | Enantiopure drugs |
Trandolapril is an ACE inhibitor used to treat high blood pressure. It may also be used to treat other conditions. It is similar in structure to another ramipril but has a cyclohexane group. It is a prodrug that must be metabolized into its active form. It has a longer half-life when compared to other agents in this class.
It was patented in 1981 and approved for medical use in 1993. It is marketed by Abbott Laboratories under the brand name Mavik. | 1 | Enantiopure drugs |
In organic chemistry, carbon tetrachloride serves as a source of chlorine in the Appel reaction.
Carbon tetrachloride made from heavy chlorine-37 has been used in the detection of neutrinos. | 0 | Greenhouse Gases |
Most sinusitis infections are caused by viruses, for which amoxicillin and amoxicillin-clavulanate are ineffective, and the small benefit gained by amoxicillin may be overridden by the adverse effects.
Amoxicillin is considered the first-line empirical treatment for most cases of uncomplicated bacterial sinusitis in children and adults when culture data is unavailable. Amoxicillin is recommended as the preferred first-line treatment for community-acquired pneumonia in adults by the National Institute for Health and Care Excellence, either alone (mild to moderate severity disease) or in combination with a macrolide. The World Health Organization (WHO) recommends amoxicillin as first-line treatment for pneumonia that is not "severe". Amoxicillin is used in post-exposure inhalation of anthrax to prevent disease progression and for prophylaxis. | 1 | Enantiopure drugs |
Ampicillin reacts with probenecid and methotrexate to decrease renal excretion. Large doses of ampicillin can increase the risk of bleeding with concurrent use of warfarin and other oral anticoagulants, possibly by inhibiting platelet aggregation. Ampicillin has been said to make oral contraceptives less effective, but this has been disputed. It can be made less effective by other antibiotic, such as chloramphenicol, erythromycin, cephalosporins, and tetracyclines. For example, tetracyclines inhibit protein synthesis in bacteria, reducing the target against which ampicillin acts. If given at the same time as aminoglycosides, it can bind to it and inactivate it. When administered separately, aminoglycosides and ampicillin can potentiate each other instead.
Ampicillin causes skin rashes more often when given with allopurinol.
Both the live cholera vaccine and live typhoid vaccine can be made ineffective if given with ampicillin. Ampicillin is normally used to treat cholera and typhoid fever, lowering the immunological response that the body has to mount. | 1 | Enantiopure drugs |
* Evalyn Bostock, (1917–1944) British actress who died from accidentally drinking carbon tetrachloride after mistaking it for her drink while working in a photographic darkroom.
* Harry Edwards (1887–1952), an American director who died from carbon tetrachloride poisoning shortly after directing his first television production.
* Zilphia Horton, (1910–1952) American musician and activist who died from accidentally drinking a glass full of carbon tetrachloride-based typewriter cleaning fluid that she mistook for water.
* Margo Jones, (1911–1955) American stage director who was exposed to the fumes of carbon tetrachloride that was used to clean off paint from a carpet. She died a week later from kidney failure.
* Jim Beck, (1919–1956), American record producer, died after exposure to carbon tetrachloride fumes that he was exposed to during cleaning recording equipment.
* Tommy Tucker, (1933–1982) American blues singer, died after using carbon tetrachloride in floor refinishing. | 0 | Greenhouse Gases |
R-454B, also known by the trademarked names Opteon XL41, Solstice 454B, and Puron Advance, is a zeotropic blend of 68.9 percent difluoromethane (R-32), a hydrofluorocarbon, and 31.1 percent 2,3,3,3-tetrafluoropropene (R-1234yf), a hydrofluoroolefin. Because of its reduced global warming potential (GWP), R-454B is intended to be an alternative to refrigerant R-410A in new equipment. R-454B has a GWP of 466, which is 78 percent lower than R-410A's GWP of 2088.
R-454B is non-toxic and mildly flammable, with an ASHRAE safety classification of A2L. In the United States, it is expected to be packaged in a container that is red or has a red band on the shoulder or top. | 0 | Greenhouse Gases |
As of 2006, there were no studies demonstrating "drug liking" scores of oral levomethamphetamine that are similar to racemic methamphetamine or dextromethamphetamine in either recreational users or medicinal users.
In recent years, tighter controls in Mexico on certain methamphetamine precursors like ephedrine and pseudoephedrine has led to a greater percentage of illicit meth from Mexican drug cartels consisting of a higher ratio of levomethamphetamine to dextromethamphetamine within batches of racemic meth. | 1 | Enantiopure drugs |
Captopril's main uses are based on its vasodilation and inhibition of some renal function activities. These benefits are most clearly seen in:
* Hypertension
* Cardiac conditions such as congestive heart failure and after myocardial infarction
* Preservation of kidney function in diabetic nephropathy.
Additionally, it has shown mood-elevating properties in some patients. This is consistent with the observation that animal screening models indicate putative antidepressant activity for this compound, although one study has been negative. Formal clinical trials in depressed patients have not been reported.
It has also been investigated for use in the treatment of cancer. Captopril stereoisomers were also reported to inhibit some metallo-β-lactamases. | 1 | Enantiopure drugs |
Hydrofluorocarbons (HFCs) contain no chlorine. They are composed entirely of carbon, hydrogen, and fluorine. They have no known effects on the ozone layer; fluorine itself is not ozone-toxic. However, HFCs and perfluorocarbons (PFCs) are greenhouse gases, which cause global warming. Two groups of haloalkanes, hydrofluorocarbons (HFCs) and perfluorocarbons, are targets of the Kyoto Protocol. Allan Thornton, President of the Environmental Investigation Agency, a non-governmental, environmental watchdog, says that HFCs are up to 12,500 times as potent as carbon dioxide in global warming. The higher global warming potential has two causes: HFCs remain in the atmosphere for long periods of time, and they have more chemical bonds than , which means that they are able to absorb more solar energy per molecule than carbon dioxide. Wealthy countries are clamping down on these gases. Thornton says that many countries are needlessly producing these chemicals just to get the carbon credits. Thus, as a result of carbon trading rules under the Kyoto Protocol, nearly half the credits from developing countries are from HFCs, with China scoring billions of dollars from catching and destroying HFCs that would be in the atmosphere as industrial byproducts. | 0 | Greenhouse Gases |
About 70% of the ingested imidapril is absorbed quickly from the gut; this percentage is reduced significantly when taken with a fatty meal. It reaches highest blood plasma concentrations after two hours and has a biological half-life of two hours. The substance is a prodrug and is activated to imidaprilat, which reaches highest plasma concentrations after 7 hours, has an initial half-life of 7 to 9 hours and a terminal half-life of more than 24 hours. The absolute bioavailability of imidaprilat is 42%.
About 40% of the drug is excreted via the urine and 50% via the bile and faeces. | 1 | Enantiopure drugs |
According to their material safety data sheets, CFCs and HCFCs are colorless, volatile, non-toxic liquids and gases with a faintly sweet ethereal odor. Overexposure at concentrations of 11% or more may cause dizziness, loss of concentration, central nervous system depression or cardiac arrhythmia. Vapors displace air and can cause asphyxiation in confined spaces. Dermal absorption of chlorofluorocarbons is possible, but low. Where the pulmonary uptake of inhaled chlorofluorocarbons occurs quickly with peak blood concentrations occurring in as little as 15 seconds with steady concentrations evening out after 20 minutes. Absorption of orally ingested chlorofluorocarbons is 35 to 48 times lower compared to inhalation. Although non-flammable, their combustion products include hydrofluoric acid and related species.
Normal occupational exposure is rated at 0.07% and does not pose any serious health risks. | 0 | Greenhouse Gases |
Esketamine is used for similar indications as ketamine. Such uses include induction of anesthesia in high-risk patients such as those with circulatory shock, severe bronchospasm, or as a supplement to regional anesthesia with incomplete nerve blocks. | 1 | Enantiopure drugs |
The most common side effects (more than 10% of patients) are hot flashes and sweating, which are typical of estrogen deficiency as caused by exemestane, and also insomnia, headache, and joint pain. Nausea and fatigue are mainly observed in patients with advanced breast cancer.
An occasional decrease in lymphocytes has been observed in approximately 20% of patients receiving Aromasin, particularly in patients with pre-existing lymphopenia.
Exemestane has androgenic properties similarly to formestane and can produce androgenic side effects such as acne and weight gain, although these are generally associated with supratherapeutic dosages of the drug. | 1 | Enantiopure drugs |
Dexlansoprazole is the (R)-(+)-enantiomer of lansoprazole, which is a racemic mixture of its (R)-(+) and (S)-(−)-enantiomers. The Takeda drug has a dual release pharmaceutical formulation, with two types of granules of dexlansoprazole, each with a coating that dissolves at a different pH level. | 1 | Enantiopure drugs |
Alternatives for normally occupied areas include (PFC-410 or CEA-410), CF (PFC-218 or CEA-308), HCFC Blend A (NAF S-III), HFC-23 (FE 13), HFC-227ea (FM 200), IG-01 (argon), IG-55 (argonite), HFC-125, or HFC-134a. For normally unoccupied areas, the alternatives include carbon dioxide, powdered Aerosol C, CFI, HCFC-22, HCFC-124, HFC-125, HFC-134a, gelled halocarbon/dry chemical suspension (PGA), blend of inert gas, high expansion foam systems and powdered aerosol (FS 0140), and IG-541 (Inergen).
Perfluorocarbons, i.e., PFCs such as CF, have very long atmospheric lifetimes and very high global warming potentials. Hydrochlorofluorocarbons, i.e., HCFCs including HCFC containing NAF S-III, contain chlorine and are stratospheric ozone layer depleters, although less so than Halon 1301. Their selection for usage as Halon replacements should consider those factors, and is restricted in some countries. | 0 | Greenhouse Gases |
Aside from its immense environmental impacts, Freon 113, like most chlorofluoroalkanes, forms phosgene gas when exposed to a naked flame. | 0 | Greenhouse Gases |
Dextrorphan was formerly a Schedule I controlled substance in the United States, but was unscheduled on October 1, 1976. | 1 | Enantiopure drugs |
Trichlorofluoromethane was first widely used as a refrigerant. Because of its high boiling point compared to most refrigerants, it can be used in systems with a low operating pressure, making the mechanical design of such systems less demanding than that of higher-pressure refrigerants R-12 or R-22.
Trichlorofluoromethane is used as a reference compound for fluorine-19 NMR studies.
Trichlorofluoromethane was formerly used in the drinking bird novelty, largely because it has a boiling point of . The replacement, dichloromethane, boiling point , requires a higher ambient temperature to work.
Prior to the knowledge of the ozone depletion potential of chlorine in refrigerants and other possible harmful effects on the environment, trichlorofluoromethane was sometimes used as a cleaning/rinsing agent for low-pressure systems. | 0 | Greenhouse Gases |
Because water has strong cohesive and adhesive forces, it exhibits capillary action. Strong cohesion from hydrogen bonding and adhesion allows trees to transport water more than 100 m upward. | 0 | Greenhouse Gases |
The primary uses of esomeprazole are gastroesophageal reflux disease, treatment and maintenance of erosive esophagitis, treatment of duodenal ulcers caused by H. pylori, prevention of gastric ulcers in those on chronic NSAID therapy, and treatment of gastrointestinal ulcers associated with Crohn's disease. | 1 | Enantiopure drugs |
A major mechanism of resistance against piperacillin-tazobactam is Gram-negative bacteria producing β-lactamases. Other currently known mechanisms include mutations in the active site of penicillin-binding proteins, changes in membrane efflux, or bacteria permeability. Some enzymes, such as extended-spectrum β-lactamase (ESBL) have evolved from narrow-spectrum β-lactamases due to genetic mutations, increasing their capabilities to hydrolyze much broader spectrum penicillin. Due to prior conflicting reports on the drug's affinity with ESBL-producing bacteria, piperacillin-tazobactam treatment for such is not recommended. Antibiotic resistance occurs sporadically, conferred by the continuous use of piperacillin-tazobactam in situations where it may prove to be ineffective, leading to cases where plasmid-mediated β-lactamases are being produced in bacteria that do not naturally produce it.
Some Gram-positive bacteria penicillin-binding proteins such as Enterococcus faecium (PBP-5) or Staphylococcus aureus (PBP-2a) are intrinsically antibiotic resistant, consisting of relatively low affinity with piperacillin and therefore high resistance to piperacillin-tazobactam. Furthermore, mutations in penicillin-binding proteins cause fluctuations in piperacillin affinity, whereas Streptococcus pneumoniae (PBP-2b) autolytic response is significantly reduced due to decreased affinity with piperacillin. Although membrane permeability changes are less common as a mechanism of resistance, studies investigating Klebsiella pneumoniae have reported a correlation between decreased permeability of piperacillin and increased SHV-1 β-lactamase production. | 1 | Enantiopure drugs |
* Respiratory tract infections (such as tonsillitis, pharyngitis, and lobar pneumonia) caused by group A beta-hemolytic streptococci and S. pneumoniae (formerly D. pneumonia).
* Otitis media caused by group A beta-hemolytic streptococci, S. pneumoniae, H. influenzae, and staphylococci.
* Skin and skin structure infections caused by staphylococci (penicillin-susceptible and penicillin-resistant) and beta-hemolytic streptococci.
* Urinary tract infections, including prostatitis, caused by E. coli, P. mirabilis and Klebsiella species. | 1 | Enantiopure drugs |
Since warming of Earth means less ice on the ground on average, it would cause lower albedo and more sunlight absorbed, hence further increasing Earth's temperature.
As a rough estimate, we note that the average temperature on most of Earth are between -20 and +30 Celsius degree, a good guess will be that 2% of its surface are between -1 and 0 °C, and thus an equivalent area of its surface will be changed from ice-covered (or snow-covered) to either ocean or forest.
For comparison, in the northern hemisphere, the arctic sea ice has shrunk between 1979 and 2015 by 1.43x10 m at maxima and 2.52x10 m at minima, for an average of almost 2x10 m, which is 0.4% of Earth's total surface of 510x10 m. At this time the global temperature rose by ~0.6 °C. The areas of inland glaciers combined (not including the antarctice ice sheet), the antarctic sea ice, and the arctic sea ice are all comparable, so one may expect the change in ice of the arctic sea ice is roughly a third of the total change, giving 1.2% of the Earth surface turned from ice to ocean or bare ground per 0.6 °C, or equivalently 2% per 1 °C. The antarctic ice cap size oscillates, and it is hard to predict its future course, with factors such as relative thermal insulated and constraints due to the Antarctic Circumpolar Current probably playing a part.
As the difference in albedo between ice and e.g. ocean is around 2/3, this means that due to a 1 °C rise, the albedo will drop by 2%*2/3 = 4/3%. However this will mainly happen in northern and southern latitudes, around 60 degrees off the equator, and so the effective area is actually 2% * cos(60) = 1%, and the global albedo drop would be 2/3%.
Since a change in radiation of 1.3% causes a direct change of 1 degree Celsius (without feedback), as calculated above, and this causes another change of 2/3% in radiation due to positive feedback, whice is half the original change, this means the total factor caused by this feedback mechanism would be:
Thus, this feedback would double the effect of the change in radiation, causing a change of ~ 2 K in the global temperature, which is indeed the commonly accepted short-term value. For long-term value, including further feedback mechanisms, ~3K is considered more probable. | 0 | Greenhouse Gases |
Cefuroxime axetil is an ester prodrug of cefuroxime which is effective when taken by mouth. It is a second-generation cephalosporin. | 1 | Enantiopure drugs |
Levopropylhexedrine (Eventin) is an adrenergic alkylamine used as an anorectic in Germany and patented by Smith Kline & French in 1947. It has also been used in the anticonvulsant preparation barbexaclone in combination with phenobarbital to offset sedation. Levopropylhexedrine is the levorotatory S-enantiomer of propylhexedrine. The dextrorotatory counterpart is known as dextropropylhexedrine. | 1 | Enantiopure drugs |
Common side effects include rash, loss of appetite, nausea, diarrhea, and low blood white blood cell levels. Other serious side effects include liver problems, obliterative bronchiolitis, and myasthenia gravis. It is not recommended in people with lupus erythematosus. Use during pregnancy may result in harm to the baby. Penicillamine works by binding heavy metals; the resulting penicillamine–metal complexes are then removed from the body in the urine.
Bone marrow suppression, dysgeusia, anorexia, vomiting, and diarrhea are the most common side effects, occurring in ~20–30% of the patients treated with penicillamine.
Other possible adverse effects include:
* Nephropathy
* Hepatotoxicity
* Membranous glomerulonephritis
* Aplastic anemia (idiosyncratic)
* Antibody-mediated myasthenia gravis and Lambert–Eaton myasthenic syndrome, which may persist even after its withdrawal
* Drug-induced systemic lupus erythematosus
* Elastosis perforans serpiginosa
* Toxic myopathies
* Unwanted breast growth
* Oligospermia | 1 | Enantiopure drugs |
Any process that results in the production of methane and its release into the atmosphere can be considered a "source". The known sources of methane are predominantly located near the Earth's surface. Two main processes that are responsible for methane production include microorganisms anaerobically converting organic compounds into methane (methanogenesis), which are widespread in aquatic ecosystems, and ruminant animals. Other natural sources include melting permafrost, wetlands, plants, and methane clathrates. | 0 | Greenhouse Gases |
CFCs were phased out via the Montreal Protocol due to their part in ozone depletion.
The atmospheric impacts of CFCs are not limited to their role as ozone-depleting chemicals. Infrared absorption bands prevent heat at that wavelength from escaping Earth's atmosphere. CFCs have their strongest absorption bands from C-F and C-Cl bonds in the spectral region of 7.8–15.3 µm—referred to as the "atmospheric window" due to the relative transparency of the atmosphere within this region.
The strength of CFC absorption bands and the unique susceptibility of the atmosphere at wavelengths where CFCs (indeed all covalent fluorine compounds) absorb radiation creates a "super" greenhouse effect from CFCs and other unreactive fluorine-containing gases such as perfluorocarbons, HFCs, HCFCs, bromofluorocarbons, SF, and NF. This "atmospheric window" absorption is intensified by the low concentration of each individual CFC. Because CO is close to saturation with high concentrations and few infrared absorption bands, the radiation budget and hence the greenhouse effect has low sensitivity to changes in CO concentration; the increase in temperature is roughly logarithmic. Conversely, the low concentration of CFCs allow their effects to increase linearly with mass, so that chlorofluorocarbons are greenhouse gases with a much higher potential to enhance the greenhouse effect than CO.
Groups are actively disposing of legacy CFCs to reduce their impact on the atmosphere.
According to NASA in 2018, the hole in the ozone layer has begun to recover as a result of CFC bans. However, research released in 2019 reports an alarming increase in CFCs, pointing to unregulated use in China. | 0 | Greenhouse Gases |
Escitalopram is effective in reducing the symptoms of premenstrual syndrome, whether taken continuously or in the luteal phase only. | 1 | Enantiopure drugs |
Common effects (1–10% incidence) include:
* Abnormal dreams
* Anisocoria
* Anorgasmia
* Anxiety
* Arthralgia (joint pain)
* Constipation
* Decreased or increased appetite
* Diarrhea
* Dilated pupils
* Dizziness
* Dry mouth
* Excessive sweating
* Fatigue
* Impotence (erectile dysfunction)
* Libido changes
* Myalgia (muscular aches and pains)
* Paraesthesia (abnormal skin sensation)
* Pyrexia (fever)
* Restlessness
* Sinusitis (nasal congestion)
* Tremor
* Vomiting
* Yawning | 1 | Enantiopure drugs |
We may make a more elaborate calculation by treating the atmosphere as compounded of many thin layers. For each such layer, at height y and thickness dy, the weight of this layer in determining the radiation temperaure seen from outer space is a generalization of the expression arrived at earlier for the troposphere. It is:
where OD(y) is the optical depth of the part of the atmosphere from y upwards.
The total effect of CO on the radiation at wavelengths λ to λ+dλ is therefore:
where B is the expression for radiation according to Planck's law presented above:
and the infinity here can be taken actually as the top of the tropopause.
Thus the effect of a relative change in CO concentration, dN/N = dn/n (where n is the density number near ground), would be (noting that dN/N = d(ln N) = d(ln n):
where we have used integration by part.
Because B does not depend on N, and because , we have:
Now, is constant in the troposphere and zero in the tropopause. We denote the height of the border between them as U. So:
The optical depth is proportional to the integral of the number density over y, as does the pressure. Therefore, OD(y) is proportional to the pressure p(y), which within the troposphere (height 0 to U) falls exponentially with decay constant 1/H (H~5.6 km for CO), thus:
Since + constant, viewed as a function of both y and N, we have:
And therefore differentiating with respect to ln N is the same as differentiating with respect to y, times a factor of .
We arrive at:
Since the temperature only changes by ~25% within the troposphere, one may take a (rough) linear approximation of B with T at the relevant wavelengths, and get:
Due to the linear approximation of B we have:
with T taken at H, so that totally:
giving the same result as in the one-layer model presented above, as well as the logarithmic dependence on N, except that now we see T is taken at 5.6 km (the pressure drop height scale), rather than 6.3 km (the density drop height scale). | 0 | Greenhouse Gases |
Levetiracetam is available as regular and extended release oral formulations and as intravenous formulations.
The immediate release tablet has been available as a generic in the United States since 2008, and in the UK since 2011. The patent for the extended release tablet will expire in 2028.
The branded version Keppra is manufactured by UCB Pharmaceuticals S.A.
In 2015, Aprecia's 3D-printed orally disintegrating tablet form of the drug was approved by the FDA, under the trade name Spritam. Some have said that the drug has been improved by 3D printing, as the formula used now has improved disintegration properties. | 1 | Enantiopure drugs |
Like lansoprazole, dexlansoprazole permanently binds to the proton pump and blocks it, preventing the formation of gastric acid. | 1 | Enantiopure drugs |
At the same temperature, a column of dry air will be denser or heavier than a column of air containing any water vapor, the molar mass of diatomic nitrogen and diatomic oxygen both being greater than the molar mass of water. Thus, any volume of dry air will sink if placed in a larger volume of moist air. Also, a volume of moist air will rise or be buoyant if placed in a larger region of dry air. As the temperature rises the proportion of water vapor in the air increases, and its buoyancy will increase. The increase in buoyancy can have a significant atmospheric impact, giving rise to powerful, moisture rich, upward air currents when the air temperature and sea temperature reaches 25 °C or above. This phenomenon provides a significant driving force for cyclonic and anticyclonic weather systems (typhoons and hurricanes). | 0 | Greenhouse Gases |
Chloromethane was first synthesized by the French chemists Jean-Baptiste Dumas and Eugene Peligot in 1835 by boiling a mixture of methanol, sulfuric acid, and sodium chloride. This method is the forerunner for that used today, which uses hydrogen chloride instead of sulfuric acid and sodium chloride.
Chloromethane is produced commercially by treating methanol with hydrochloric acid or hydrogen chloride, according to the chemical equation:
: CHOH + HCl → CHCl + HO
A smaller amount of chloromethane is produced by treating a mixture of methane with chlorine at elevated temperatures. This method, however, also produces more highly chlorinated compounds such as dichloromethane, chloroform, and carbon tetrachloride. For this reason, methane chlorination is usually only practiced when these other products are also desired. This chlorination method also cogenerates hydrogen chloride, which poses a disposal problem.
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