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LC50
In toxicology, the median lethal dose, LD50 (abbreviation for " lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a toxin, radiation, or pathogen. The value of LD50 for a substance is the dose required to kill half the members of a tested population after a specified test duration. LD50 figures are frequently used as a general indicator of a substance's acute toxicity. A lower LD50 is indicative of increased toxicity. The test was created by J.W. Trevan in 1927. The term semilethal dose is occasionally used in the same sense, in particular with translations of foreign language text, but can also refer to a sublethal dose. LD50 is usually determined by tests on animals such as laboratory mice. In 2011, the U.S. Food and Drug Administration approved alternative methods to LD50 for testing the cosmetic drug Botox without animal tests. Conventions The LD50 is usually expressed as the mass of substance administered per u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxic Unit
Toxic units (TU) are used in the field of toxicology to quantify the interactions of toxicants in binary mixtures of chemicals. A toxic unit for a given compound is based on the concentration at which there is a 50% effect (ex. EC50) for a certain biological endpoint. One toxic unit is equal to the EC50 for a given endpoint for a specific biological effect over a given amount of time. Toxic units allow for the comparison of the individual toxicities of a binary mixture to the combined toxicity. This allows researchers to categorize mixtures as additive, synergistic or antagonistic. Synergism and antagonism are defined by mixtures that are more or less toxic than predicted by the sum of their toxic units. Contamination, Contaminants are frequently present as mixtures in the environment. Regulatory decisions are based on mixture toxicity models that assume additivity, which can result in under or overestimation of toxic effects. Refining our understanding of mixture interactions can l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lethal Dose
In toxicology, the lethal dose (LD) is an indication of the lethal toxicity of a given substance or type of radiation. Because resistance varies from one individual to another, the "lethal dose" represents a dose (usually recorded as dose per kilogram of subject body weight) at which a given ''percentage'' of subjects will die. The lethal concentration is a lethal dose measurement used for gases or particulates. The LD may be based on the standard person concept, a theoretical individual that has perfectly "normal" characteristics, and thus not apply to all sub-populations. Median lethal dose (LD50) The median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 (lethal concentration and time) of a toxin, radiation, or pathogen is the dose required to kill half the members of a tested population after a specified test duration. LD50 figures are frequently used as a general indicator of a substance's acute toxicity. A lower LD50 is indi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Cyanide
Hydrogen cyanide, sometimes called prussic acid, is a chemical compound with the formula HCN and structure . It is a colorless, extremely poisonous, and flammable liquid that boils slightly above room temperature, at . HCN is produced on an industrial scale and is a highly valued precursor to many chemical compounds ranging from polymers to pharmaceuticals. Large-scale applications are for the production of potassium cyanide and adiponitrile, used in mining and plastics, respectively. It is more toxic than solid cyanide compounds due to its volatile nature. Structure and general properties Hydrogen cyanide is a linear molecule, with a triple bond between carbon and nitrogen. The tautomer of HCN is HNC, hydrogen isocyanide. Hydrogen cyanide is weakly acidic with a p''K''a of 9.2. It partially ionizes in water solution to give the cyanide anion, CN−. A solution of hydrogen cyanide in water, represented as HCN, is called ''hydrocyanic acid''. The salts of the cyanid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxicology
Toxicology is a scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms and the practice of diagnosing and treating exposures to toxins and toxicants. The relationship between dose and its effects on the exposed organism is of high significance in toxicology. Factors that influence chemical toxicity include the dosage, duration of exposure (whether it is acute or chronic), route of exposure, species, age, sex, and environment. Toxicologists are experts on poisons and poisoning. There is a movement for evidence-based toxicology as part of the larger movement towards evidence-based practices. Toxicology is currently contributing to the field of cancer research, since some toxins can be used as drugs for killing tumor cells. One prime example of this is ribosome-inactivating proteins, tested in the treatment of leukemia. The word ''toxicology'' () is a n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Venom
Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a stinger, in a process called envenomation. Venom is often distinguished from poison, which is a toxin that is passively delivered by being ingested, inhaled, or absorbed through the skin, and toxungen, which is actively transferred to the external surface of another animal via a physical delivery mechanism. Venom has evolved in terrestrial and marine environments and in a wide variety of animals: both predators and prey, and both vertebrates and invertebrates. Venoms kill through the action of at least four major classes of toxin, namely necrotoxins and cytotoxins, which kill cells; neurotoxins, which affect nervous systems; myotoxins, which damage muscles; and haemotoxins, which disrupt blood clotting. Venomous animals cause tens of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Health Effects Of Chocolate
The health effects of chocolate are the possible effects on health of consuming chocolate, mainly over the long term. Commonly consumed chocolate is high in fat and sugar, which are associated with an increased risk for obesity when consumed in excess. Depending on the cocoa content, chocolate can contain variable amounts of other compounds, such as polyphenols, in particular flavan-3-ols, and theobromine. Clinical research studies are insufficient to confirm an effect of chocolate on long-term health. History ''Theobroma cacao'', the cacao tree, produces seeds containing flavanols. The seeds were used to make beverages over some 2000 years in Aztec, Olmec, and Maya civilizations in Central and South America. The drinks were ascribed various curative and stimulant properties, unsupported by experimental evidence. In the 19th century, chocolate as a solid was invented, and milk and sugar were added to create milk chocolate, which is high in fat and sugar. Throughout history, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paracetamol Toxicity
Paracetamol poisoning, also known as acetaminophen poisoning, is caused by excessive use of the medication paracetamol (acetaminophen). Most people have few or non-specific symptoms in the first 24 hours following overdose. These include feeling tired, abdominal pain, or nausea. This is typically followed by a couple of days without any symptoms, after which yellowish skin, blood clotting problems, and confusion occurs as a result of liver failure. Additional complications may include kidney failure, pancreatitis, low blood sugar, and lactic acidosis. If death does not occur, people tend to recover fully over a couple of weeks. Without treatment, death from toxicity occurs 4 to 18 days later. Paracetamol poisoning can occur accidentally or as an attempt to die by suicide. Risk factors for toxicity include alcoholism, malnutrition, and the taking of certain other hepatotoxic medications. Liver damage results not from paracetamol itself, but from one of its metabolites, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Warfare
Biological warfare, also known as germ warfare, is the use of biological toxins or infectious agents such as bacteria, viruses, insects, and fungi with the intent to kill, harm or incapacitate humans, animals or plants as an act of war. Biological weapons (often termed "bio-weapons", "biological threat agents", or "bio-agents") are living organisms or replicating entities ( ''i.e.'' viruses, which are not universally considered "alive"). Entomological (insect) warfare is a subtype of biological warfare. Offensive biological warfare is prohibited under customary international humanitarian law and several international treaties. In particular, the 1972 Biological Weapons Convention (BWC) bans the development, production, acquisition, transfer, stockpiling and use of biological weapons. Therefore, the use of biological agents in armed conflict is a war crime. In contrast, defensive biological research for prophylactic, protective or other peaceful purposes is not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Material Safety Data Sheet
A safety data sheet (SDS), material safety data sheet (MSDS), or product safety data sheet (PSDS) is a document that lists information relating to occupational safety and health for the use of various substances and products. SDSs are a widely used system for cataloguing information on chemicals, chemical compounds, and chemical mixtures. SDS information may include instructions for the safe use and potential hazards associated with a particular material or product, along with spill-handling procedures. The older MSDS formats could vary from source to source within a country depending on national requirements; however, the newer SDS format is internationally standardized. An SDS for a substance is not primarily intended for use by the general consumer, focusing instead on the hazards of working with the material in an occupational setting. There is also a duty to properly label substances on the basis of physico-chemical, health, or environmental risk. Labels can include haz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haber's Law
In toxicology, Haber's rule or Haber's law is a mathematical statement of the relationship between the concentration of a poisonous gas and how long the gas must be breathed to produce death, or other toxic effect. The rule was formulated by German chemist Fritz Haber in the early 1900s. Rule Haber's rule states that, for a given poisonous gas, tC = k, where C is the concentration of the gas (mass per unit volume), t is the amount of time necessary to breathe the gas to produce a given toxic effect, and k is a constant, depending on both the gas and the effect. Thus, the rule states that doubling the concentration will halve the time, for example. It makes equivalent any two groupings of dose concentration and exposure time that have equivalent mathematical products. For instance, if we assign dose concentration the symbol C, and time the classic t, then for any two dose schema, if C1t1=C2t2, then under Haber's rule the two dose schema are equivalent. Haber's rule is an appro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fritz Haber
Fritz Haber (; 9 December 186829 January 1934) was a German chemist who received the Nobel Prize in Chemistry in 1918 for his invention of the Haber–Bosch process, a method used in industry to synthesize ammonia from nitrogen gas and hydrogen gas. This invention is important for the large-scale synthesis of fertilisers and explosives. It is estimated that one-third of annual global food production uses ammonia from the Haber–Bosch process, and that this supports nearly half of the world's population. Haber, along with Max Born, proposed the Born–Haber cycle as a method for evaluating the lattice energy of an ionic solid. Haber, a known German nationalist, is also considered the "father of chemical warfare" for his years of pioneering work developing and weaponising chlorine and other poisonous gases during World War I, especially his actions during the Second Battle of Ypres. His work was later also used to develop Zyklon B, used for the murder of more than 1 million of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Warfare
Chemical warfare (CW) involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from nuclear warfare, biological warfare and radiological warfare, which together make up CBRN, the military acronym for chemical, biological, radiological, and nuclear (warfare or weapons), all of which are considered " weapons of mass destruction" (WMDs), a term that contrasts with conventional weapons. The use of chemical weapons is prohibited under customary international humanitarian law. Definition Chemical warfare is different from the use of conventional weapons or nuclear weapons because the destructive effects of chemical weapons are not primarily due to any explosive force. The offensive use of living organisms (such as anthrax) is considered biological warfare rather than chemical warfare; however, the use of nonliving toxic products produced by living organisms (e.g. toxins such as botulinum toxin, ricin, and saxitoxin) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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