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Acute Toxicity
Acute toxicity describes the adverse effects of a substance that result either from a single exposure or from multiple exposures in a short period of time (usually less than 24 hours). To be described as ''acute'' toxicity, the adverse effects should occur within 14 days of the administration of the substance. Acute toxicity is distinguished from chronic toxicity, which describes the adverse health effects from repeated exposures, often at lower levels, to a substance over a longer time period (months or years). It is widely considered unethical to use humans as test subjects for acute (or chronic) toxicity research. However, some information can be gained from investigating accidental human exposures (e.g., factory accidents). Otherwise, most acute toxicity data comes from animal testing or, more recently, ''in vitro'' testing methods and inference Inferences are steps in logical reasoning, moving from premises to logical consequences; etymologically, the word ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Chronic Toxicity
Chronic toxicity, the development of adverse effects as a result of long term exposure to a contaminant or other stressor, is an important aspect of aquatic toxicology. Adverse effects associated with chronic toxicity can be directly lethal but are more commonly sublethal, including changes in growth, reproduction, or behavior. Chronic toxicity is in contrast to acute toxicity, which occurs over a shorter period of time to higher concentrations. Various toxicity tests can be performed to assess the chronic toxicity of different contaminants, and usually last at least 10% of an organism's lifespan. Results of aquatic chronic toxicity tests can be used to determine water quality guidelines and regulations for protection of aquatic organisms. Definition Chronic toxicity is the development of adverse effects as the result of long term exposure to a toxicant or other stressor. It can manifest as direct lethality but more commonly refers to sublethal endpoints such as decreased growth, r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Maximum Tolerable Dose
The therapeutic index (TI; also referred to as therapeutic ratio) is a quantitative measurement of the relative safety of a drug with regard to risk of overdose. It is a comparison of the amount of a therapeutic agent that causes toxicity to the amount that causes the therapeutic effect. The related terms therapeutic window or safety window refer to a range of doses optimized between efficacy and toxicity, achieving the greatest therapeutic benefit without resulting in unacceptable side-effects or toxicity. Classically, for clinical indications of an approved drug, TI refers to the ratio of the dose of the drug that causes adverse effects at an incidence/severity not compatible with the targeted indication (e.g. toxic dose in 50% of subjects, TD) to the dose that leads to the desired pharmacological effect (e.g. efficacious dose in 50% of subjects, ED). In contrast, in a drug development setting TI is calculated based on plasma exposure levels. In the early days of pharmaceuti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Activated Carbon
Activated carbon, also called activated charcoal, is a form of carbon commonly used to filter contaminants from water and air, among many other uses. It is processed (activated) to have small, low-volume pores that greatly increase the surface area available for ''adsorption '' or chemical reactions. (Adsorption, not to be confused with Absorption (chemistry), absorption, is a process where atoms or molecules adhere to a surface). The pores can be thought of as a microscopic "sponge" structure. Activation is analogous to making popcorn from dried corn kernels: popcorn is light, fluffy, and its kernels have a high surface-area-to-volume ratio. ''Activated'' is sometimes replaced by ''active''. Because it is so porous on a microscopic scale, one gram of activated carbon has a surface area of over , as determined by gas absorption and its porosity can run 10ML/day in terms of treated water per gram. Researchers at Cornell University synthesized an ultrahigh surface area activated ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Eyewash
Eyewash is a fluid, commonly saline, used to physically wash the eyes in the case that they may be contaminated by foreign materials or substances. Eyewashes may be beneficial to those with sensitive eyes and can provide relief to the painful side effects of sensitivity. However, prolonged usage of such products will cause mild side effects, such as the reddening of the eye and/or pupil and cause itchiness. Occupational safety In the United States, the Occupational Safety and Health Administration The Occupational Safety and Health Administration (OSHA; ) is a regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. The United States Congress established ... (OSHA) was created as a result of the Occupational Safety and Health Act of 1970. The law was created to help further protect employee safety while providing "safe & healthful working conditions." OSHA's primary eyewash standard, 29 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Shower
A shower is a place in which a person bathes under a spray of typically warm or hot water. Indoors, there is a drain in the floor. Most showers are set up to have adjustable temperature, spray pressure and showerhead nozzle angle. The simplest showers have a swivelling nozzle aimed downward, while more complex showers have a showerhead connected to a hose that has a mounting bracket; this allows the showerer to hold the showerhead by hand to spray the water onto different parts of their body. A showerhead can be installed in a small shower stall, or bathtub, with a plastic shower curtain or door. Showering is common due to the efficiency of using it compared with using a bathtub. Its use in hygiene is, therefore, common practice. History Waterfalls have historically been used as primitive forms of showers. The falling water rinsed the bathers completely clean and was more efficient than bathing in a traditional basin, which required manual transport of both fresh and was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Absolute Lethal Dose
Absolute may refer to: Companies * Absolute Entertainment, a video game publisher * Absolute Radio, (formerly Virgin Radio), independent national radio station in the UK * Absolute Software Corporation, specializes in security and data risk management * Absolut Vodka, a brand of Swedish vodka Mathematics and science * Absolute (geometry), the quadric at infinity * Absolute (perfumery), a fragrance substance produced by solvent extraction * Absolute infinite or Tav (number), a number that is bigger than any other conceivable or inconceivable quantity * Absolute magnitude, the brightness of a star * Absolute value, a notion in mathematics, commonly a number's numerical value without regard to its sign * Absolute pressure, the pressure in a fluid, measured relative to a vacuum *Absolute temperature, a temperature on the thermodynamic temperature scale * Absolute zero, the lower limit of the thermodynamic temperature scale, -273.15 °C * Absoluteness (logic), a concept in mathe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
LT50
LT50 is the median Lethal Time (time until death) after exposure of an organism to a toxic substance or stressful condition. LT50 is commonly used in toxicology studies to quantify amount of a stressor necessary to kill an organism. LT50 can be used in conjunction with EC50 (median Exposure Concentration) for even more precise quantification. See also * Acute toxicity * Viability assay A viability assay is an assay that is created to determine the ability of organs, cells or tissues to maintain or recover a state of survival. Viability can be distinguished from the all-or-nothing states of life and death by the use of a quanti ... References Toxicology {{toxicology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Median Lethal Time
The median of a set of numbers is the value separating the higher half from the lower half of a data sample, a population, or a probability distribution. For a data set, it may be thought of as the “middle" value. The basic feature of the median in describing data compared to the mean (often simply described as the "average") is that it is not skewed by a small proportion of extremely large or small values, and therefore provides a better representation of the center. Median income, for example, may be a better way to describe the center of the income distribution because increases in the largest incomes alone have no effect on the median. For this reason, the median is of central importance in robust statistics. Median is a 2-quantile; it is the value that partitions a set into two equal parts. Finite set of numbers The median of a finite list of numbers is the "middle" number, when those numbers are listed in order from smallest to greatest. If the data set has an odd number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Median Lethal Dose
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 given substance. 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 higher toxicity. The term LD50 is generally attributed to John William Trevan. 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 expr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Median Lethal Concentration
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 given substance. 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 higher toxicity. The term LD50 is generally attributed to John William Trevan. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Minimum 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] [Amazon] |
