Alcoholic drink
An alcoholic drink is a drink that contains ethanol, a type of alcohol produced by fermentation of grains, fruits, or other sources of sugar. Drinking alcohol plays an important social role in many cultures. Most countries have laws regulating the production and consumption of alcoholic beverages; some countries ban such activities but alcoholic drinks are legal in most parts of the world. The global alcoholic drink industry exceeded $1 trillion in 2014. Alcohol is a depressant, which in low doses causes euphoria, reduces anxiety, improves sociability. In higher doses, it causes drunkenness, unconsciousness, or death. Long-term use can lead to alcohol abuse, physical dependence, alcoholism. Alcohol is one of the most used recreational drugs in the world with about 33% of people being current drinkers; as of 2016 women on average drink 0.7 drinks and males 1.7 drinks a day. In 2015, among Americans, 86% of adults had consumed alcohol at some point, 70% had drunk it in the last year, 56% in the last month.
Alcoholic drinks are divided into three classes—beers and spirits—and their alcohol content is between 3% and 50%. Discovery of late Stone Age jugs suggest that intentionally fermented drinks existed at least as early as the Neolithic period. Many animals consume alcohol when given the opportunity and are affected in much the same way as humans, although humans are the only species known to produce alcoholic drinks intentionally. Beer is a beverage fermented from grain mash, it is made from barley or a blend of several grains and flavored with hops. Most beer is carbonated as part of the fermentation process. If the fermented mash is distilled the drink becomes a spirit. In the Andean region, the most common beer is chicha, made from grain or fruits. Beer is the most consumed alcoholic beverage in the world. Cider or cyder is a fermented alcoholic drink made from any fruit juice. Cider alcohol content varies from 1.2% ABV to 8.5% or more in traditional English ciders. In some regions, cider may be called "apple wine".
Mead is an alcoholic drink made by fermenting honey with water, sometimes with various fruits, grains, or hops. The alcoholic content of mead may range from about 8% ABV to more than 20%; the defining characteristic of mead is that the majority of the drink's fermentable sugar is derived from honey. Pulque is the Mesoamerican fermented drink made from the "honey water" of maguey cacti; the drink distilled from pulque is mescal. Wine is a fermented beverage produced from sometimes other fruits. Wine involves a longer fermentation process than beer and a long aging process, resulting in an alcohol content of 9%–16% ABV. "Fruit wines" are made from fruits other than grapes, such as cherries, or apples. Sake is a popular example of "rice wine". Sparkling wine like French Champagne, Catalan Cava or Italian Prosecco can be made by means of a secondary fermentation. A distilled drink or liquor is an alcoholic drink produced by distilling ethanol produced by means of fermenting grain, fruit, or vegetables.
Unsweetened, alcoholic drinks that have an alcohol content of at least 20% ABV are called spirits. For the most common distilled drinks, such as whiskey and vodka, the alcohol content is around 40%; the term hard liquor is used in North America to distinguish distilled drinks from undistilled ones. Vodka, baijiu, whiskey and soju are examples of distilled drinks. Distilling eliminates some of the congeners. Freeze distillation concentrates ethanol along with fusel alcohols in applejack. Fortified wine is wine, such as sherry, to which a distilled beverage has been added. Fortified wine is distinguished from spirits made from wine in that spirits are produced by means of distillation, while fortified wine is wine that has had a spirit added to it. Many different styles of fortified wine have been developed, including port, madeira, marsala and the aromatized wine vermouth. Rectified spirit called "neutral grain spirit", is alcohol, purified by means of "rectification"; the term neutral refers to the spirit's lack of the flavor that would have been present if the mash ingredients had been distilled to a lower level of alcoholic purity.
Rectified spirit lacks any flavoring added to it after distillation. Other kinds of spirits, such as whiskey, are distilled to a lower alcohol percentage to preserve the flavor of the mash. Rectified spirit is a clear, flammable liquid that may contain as much as 95% ABV, it is used for medicinal purposes. It may be a grain spirit or it may be made from other plants, it is used in mixed drinks and tinctures, as a household solvent. Alcohol has significant negative health effects, including increased risk of cancer. Negative effects are related to the amount consumed with no safe lower limit seen. Wine, distilled spirits and other alcoholic drinks contain ethyl alcohol and alcohol consumption has short-term psychological and physiological effects on the user. Different concentrations of alcohol in the human body have different effects on a person; the effects of alcohol depend on the amount an individual has drunk, the percentage of alcohol in the wine, beer or spirits and the timespan that the consumption took place, the amount of food eaten and whether an indiv
Controlled Substances Act
The Controlled Substances Act is the statute establishing federal U. S. drug policy under which the manufacture, possession and distribution of certain substances is regulated. It was passed by the 91st United States Congress as Title II of the Comprehensive Drug Abuse Prevention and Control Act of 1970 and signed into law by President Richard Nixon; the Act served as the national implementing legislation for the Single Convention on Narcotic Drugs. The legislation created five schedules, with varying qualifications for a substance to be included in each. Two federal agencies, the Drug Enforcement Administration and the Food and Drug Administration, determine which substances are added to or removed from the various schedules, although the statute passed by Congress created the initial listing. Congress has sometimes scheduled other substances through legislation such as the Hillory J. Farias and Samantha Reid Date-Rape Prevention Act of 2000, which placed gamma hydroxybutyrate in Schedule I and sodium oxybate in Schedule III.
Classification decisions are required to be made on criteria including potential for abuse accepted medical use in treatment in the United States, international treaties. The nation first outlawed addictive drugs in the early 1900s and the International Opium Convention helped lead international agreements regulating trade; the Food and Drugs Act of 1906 was the beginning of over 200 laws concerning public health and consumer protections. Others were the Federal Food and Cosmetic Act, the Kefauver Harris Amendment of 1962. In 1969, President Richard Nixon announced that the Attorney General, John N. Mitchell, was preparing a comprehensive new measure to more meet the narcotic and dangerous drug problems at the federal level by combining all existing federal laws into a single new statute. With the help of White House Counsel head, John Dean; the CSA not only combined existing federal drug laws and expanded their scope, but it changed the nature of federal drug law policies and expanded Federal law enforcement pertaining to controlled substances.
Title II, Part F of the Comprehensive Drug Abuse Prevention and Control Act of 1970 established the National Commission on Marijuana and Drug Abuse—known as the Shafer Commission after its chairman, Raymond P. Shafer—to study cannabis abuse in the United States. During his presentation of the commission's First Report to Congress and Shafer recommended the decriminalization of marijuana in small amounts, with Shafer stating, he criminal law is too harsh a tool to apply to personal possession in the effort to discourage use, it implies. The actual and potential harm of use of the drug is not great enough to justify intrusion by the criminal law into private behavior, a step which our society takes only with the greatest reluctance. Rufus King notes that this stratagem was similar to that used by Harry Anslinger when he consolidated the previous anti-drug treaties into the Single Convention and took the opportunity to add new provisions that otherwise might have been unpalatable to the international community.
According to David T. Courtwright, "the Act was part of an omnibus reform package designed to rationalize, in some respects to liberalize, American drug policy." It provided support for drug treatment and research. King notes that the rehabilitation clauses were added as a compromise to Senator Jim Hughes, who favored a moderate approach; the bill, as introduced by Senator Everett Dirksen, ran to 91 pages. While it was being drafted, the Uniform Controlled Substances Act, to be passed by state legislatures, was being drafted by the Department of Justice. Since its enactment in 1970, the Act has been amended numerous times: The 1976 Medical Device Regulation Act; the Psychotropic Substances Act of 1978 added provisions implementing the Convention on Psychotropic Substances. The Controlled Substances Penalties Amendments Act of 1984; the 1986 Federal Analog Act for chemicals "substantially similar" in Schedule I and II to be listed The 1988 Chemical Diversion and Trafficking Act added provisions implementing the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances that went into force on November 11, 1990.
1990 The Anabolic Steroids Act, passed as part of the Crime Control Act of 1990, which placed anabolic steroids into Schedule III The 1993 Domestic Chemical Diversion and Control Act in response to methamphetamine trafficking. The 2008 Ryan Haight Online Pharmacy Consumer Protection Act The 2010 Electronic Prescriptions for Controlled Substances; the 2010 Secure and Responsible Drug Disposal Act, to allow pharmacies to operate take-back programs for controlled subtance medications in response to the US opioid epidemic. The Controlled Substances Act consists of 2 subchapters. Subchapter I defines Schedules I-V, lists chemicals used in the manufacture of controlled substances, differentiates lawful and unlawful manufacturing and possession of controlled substances, including possession of Schedule I drugs for personal use.
GABA receptor
The GABA receptors are a class of receptors that respond to the neurotransmitter gamma-aminobutyric acid, the chief inhibitory compound in the mature vertebrate central nervous system. There are two classes of GABA receptors: GABAA and GABAB. GABAA receptors are ligand-gated ion channels, it has long been recognized that the fast response of neurons to GABA, blocked by bicuculline and picrotoxin is due to direct activation of an anion channel. This channel was subsequently termed the GABAA receptor. Fast-responding GABA receptors are members of a family of Cys-loop ligand-gated ion channels. Members of this superfamily, which includes nicotinic acetylcholine receptors, GABAA receptors, glycine and 5-HT3 receptors, possess a characteristic loop formed by a disulfide bond between two cysteine residues. In ionotropic GABAA receptors, binding of GABA molecules to their binding sites in the extracellular part of the receptor triggers opening of a chloride ion-selective pore; the increased chloride conductance drives the membrane potential towards the reversal potential of the Cl¯ ion, about –75 mV in neurons, inhibiting the firing of new action potentials.
This mechanism is responsible for the sedative effects of GABAA allosteric agonists. In addition, activation of GABA receptors lead to the so-called shunting inhibition, which reduces the excitability of the cell independent of the changes in membrane potential. There have been numerous reports of excitatory GABAA receptors. According to the excitatory GABA theory, this phenomenon is due to increased intracellular concentration of Cl¯ ions either during development of the nervous system or in certain cell populations. After this period of development, a chloride pump is upregulated and inserted into the cell membrane, pumping Cl− ions into the extracellular space of the tissue. Further openings via GABA binding to the receptor produce inhibitory responses. Over-excitation of this receptor induces receptor remodeling and the eventual invagination of the GABA receptor; as a result, further GABA binding becomes inhibited and inhibitory postsynaptic potentials are no longer relevant. However, the excitatory GABA theory has been questioned as being an artefact of experimental conditions, with most data acquired in in-vitro brain slice experiments susceptible to un-physiological milieu such as deficient energy metabolism and neuronal damage.
The controversy arose when a number of studies have shown that GABA in neonatal brain slices becomes inhibitory if glucose in perfusate is supplemented with ketone bodies, pyruvate, or lactate, or that the excitatory GABA was an artefact of neuronal damage. Subsequent studies from originators and proponents of the excitatory GABA theory have questioned these results, but the truth remained elusive until the real effects of GABA could be reliably elucidated in intact living brain. Since using technology such as in-vivo electrophysiology/imaging and optogenetics, two in-vivo studies have reported the effect of GABA on neonatal brain, both have shown that GABA is indeed overall inhibitory, with its activation in the developing rodent brain not resulting in network activation, instead leading to a decrease of activity. GABA receptors influence neural function by coordinating with glutamatergic processes. A subclass of ionotropic GABA receptors, insensitive to typical allosteric modulators of GABAA receptor channels such as benzodiazepines and barbiturates, was designated GABAС receptor.
Native responses of the GABAC receptor type occur in retinal bipolar or horizontal cells across vertebrate species. GABAС receptors are composed of ρ subunits that are related to GABAA receptor subunits. Although the term "GABAС receptor" is used, GABAС may be viewed as a variant within the GABAA receptor family. Others have argued that the differences between GABAС and GABAA receptors are large enough to justify maintaining the distinction between these two subclasses of GABA receptors. However, since GABAС receptors are related in sequence and function to GABAA receptors and since other GABAA receptors besides those containing ρ subunits appear to exhibit GABAС pharmacology, the Nomenclature Committee of the IUPHAR has recommended that the GABAС term no longer be used and these ρ receptors should be designated as the ρ subfamily of the GABAA receptors. A slow response to GABA is mediated by GABAB receptors defined on the basis of pharmacological properties. In studies focused on the control of neurotransmitter release, it was noted that a GABA receptor was responsible for modulating evoked release in a variety of isolated tissue preparations.
This ability of GABA to inhibit neurotransmitter release from these preparations was not blocked by bicuculline, was not mimicked by isoguvacine, was not dependent on Cl¯, all of which are characteristic of the GABAA receptor. The most striking discovery was the finding that baclofen, a clinically employed muscle relaxant mimicked, in a stereoselective manner, the effect of GABA. Ligand-binding studies provided direct evidence of binding sites for baclofen on central neuronal membranes. CDNA cloning confirmed. Additional information on GABAB receptors has been reviewed elsewhere. GABA agonist GABA antagonist IUPHAR GPCR Database - GABAB receptors GABA+Receptor at the US National Library of Medicine Medical Subject Headings
Benzodiazepine
Benzodiazepines, sometimes called "benzos", are a class of psychoactive drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. The first such drug, was discovered accidentally by Leo Sternbach in 1955, made available in 1960 by Hoffmann–La Roche, since 1963, has marketed the benzodiazepine diazepam. In 1977 benzodiazepines were globally the most prescribed medications, they are in the family of drugs known as minor tranquilizers. Benzodiazepines enhance the effect of the neurotransmitter gamma-aminobutyric acid at the GABAA receptor, resulting in sedative, anxiolytic and muscle relaxant properties. High doses of many shorter-acting benzodiazepines may cause anterograde amnesia and dissociation; these properties make benzodiazepines useful in treating anxiety, agitation, muscle spasms, alcohol withdrawal and as a premedication for medical or dental procedures. Benzodiazepines are categorized as either intermediary, or long-acting. Short- and intermediate-acting benzodiazepines are preferred for the treatment of insomnia.
Benzodiazepines are viewed as safe and effective for short-term use, although cognitive impairment and paradoxical effects such as aggression or behavioral disinhibition occur. A minority of people can have paradoxical reactions such as worsened panic. Benzodiazepines are associated with increased risk of suicide. Long-term use is controversial because of concerns about decreasing effectiveness, physical dependence, an increased risk of dementia. Stopping benzodiazepines leads to improved physical and mental health; the elderly are at an increased risk of both short- and long-term adverse effects, as a result, all benzodiazepines are listed in the Beers List of inappropriate medications for older adults. There is controversy concerning the safety of benzodiazepines in pregnancy. While they are not major teratogens, uncertainty remains as to whether they cause cleft palate in a small number of babies and whether neurobehavioural effects occur as a result of prenatal exposure. Benzodiazepines can cause dangerous deep unconsciousness.
However, they are less toxic than their predecessors, the barbiturates, death results when a benzodiazepine is the only drug taken. When combined with other central nervous system depressants such as alcoholic drinks and opioids, the potential for toxicity and fatal overdose increases. Benzodiazepines are misused and taken in combination with other drugs of abuse. Benzodiazepines possess psycholeptic, hypnotic, anticonvulsant, muscle relaxant, amnesic actions, which are useful in a variety of indications such as alcohol dependence, anxiety disorders, panic and insomnia. Most are administered orally. In general, benzodiazepines are well-tolerated and are safe and effective drugs in the short term for a wide range of conditions. Tolerance can develop to their effects and there is a risk of dependence, upon discontinuation a withdrawal syndrome may occur; these factors, combined with other possible secondary effects after prolonged use such as psychomotor, cognitive, or memory impairments, limit their long-term applicability.
The effects of long-term use or misuse include the tendency to cause or worsen cognitive deficits and anxiety. The College of Physicians and Surgeons of British Columbia recommends discontinuing the usage of benzodiazepines in those on opioids and those who have used them long term. Benzodiazepines can have serious adverse health outcomes, these findings support clinical and regulatory efforts to reduce usage in combination with non-benzodiazepine receptor agonists; because of their effectiveness and rapid onset of anxiolytic action, benzodiazepines are used for the treatment of anxiety associated with panic disorder. However, there is disagreement among expert bodies regarding the long-term use of benzodiazepines for panic disorder; the views range from those that hold that benzodiazepines are not effective long-term and that they should be reserved for treatment-resistant cases to those that hold that they are as effective in the long term as selective serotonin reuptake inhibitors. The American Psychiatric Association guidelines note that, in general, benzodiazepines are well tolerated, their use for the initial treatment for panic disorder is supported by numerous controlled trials.
APA states that there is insufficient evidence to recommend any of the established panic disorder treatments over another. The choice of treatment between benzodiazepines, SSRIs, serotonin–norepinephrine reuptake inhibitors, tricyclic antidepressants, psychotherapy should be based on the patient's history and other individual characteristics. Selective serotonin reuptake inhibitors are to be the best choice of pharmacotherapy for many patients with panic disorder, but benzodiazepines are often used, some studies suggest that these medications are still used with greater frequency than the SSRIs. One advantage of benzodiazepines is that they alleviate the anxiety symptoms much faster than antidepressants, therefore may be preferred in patients for whom rapid symptom control is critical. However, this advantage is offset by the possibility of developing benzodiazepine dependence. APA does not recommend benzodiazepines for persons with depressive
Jmol
Jmol is computer software for molecular modelling chemical structures in 3-dimensions. Jmol returns a 3D representation of a molecule that may be used as a teaching tool, or for research e.g. in chemistry and biochemistry. It is written in the programming language Java, so it can run on the operating systems Windows, macOS, Unix, if Java is installed, it is free and open-source software released under a GNU Lesser General Public License version 2.0. A standalone application and a software development kit exist that can be integrated into other Java applications, such as Bioclipse and Taverna. A popular feature is an applet that can be integrated into web pages to display molecules in a variety of ways. For example, molecules can be displayed as ball-and-stick models, space-filling models, ribbon diagrams, etc. Jmol supports a wide range of chemical file formats, including Protein Data Bank, Crystallographic Information File, MDL Molfile, Chemical Markup Language. There is a JavaScript-only version, JSmol, that can be used on computers with no Java.
The Jmol applet, among other abilities, offers an alternative to the Chime plug-in, no longer under active development. While Jmol has many features that Chime lacks, it does not claim to reproduce all Chime functions, most notably, the Sculpt mode. Chime requires plug-in installation and Internet Explorer 6.0 or Firefox 2.0 on Microsoft Windows, or Netscape Communicator 4.8 on Mac OS 9. Jmol operates on a wide variety of platforms. For example, Jmol is functional in Mozilla Firefox, Internet Explorer, Google Chrome, Safari. Chemistry Development Kit Comparison of software for molecular mechanics modeling Jmol extension for MediaWiki List of molecular graphics systems Molecular graphics Molecule editor Proteopedia PyMOL SAMSON Official website Wiki with listings of websites and moodles Willighagen, Egon. "Fast and Scriptable Molecular Graphics in Web Browsers without Java3D". Doi:10.1038/npre.2007.50.1
Pharmacokinetics
Pharmacokinetics, sometimes abbreviated as PK, is a branch of pharmacology dedicated to determine the fate of substances administered to a living organism. The substances of interest include any chemical xenobiotic such as: pharmaceutical drugs, food additives, etc, it attempts to analyze chemical metabolism and to discover the fate of a chemical from the moment that it is administered up to the point at which it is eliminated from the body. Pharmacokinetics is the study of how an organism affects a drug, whereas pharmacodynamics is the study of how the drug affects the organism. Both together influence dosing and adverse effects, as seen in PK/PD models. Pharmacokinetics describes how the body affects a specific xenobiotic/chemical after administration through the mechanisms of absorption and distribution, as well as the metabolic changes of the substance in the body, the effects and routes of excretion of the metabolites of the drug. Pharmacokinetic properties of chemicals are affected by the route of administration and the dose of administered drug.
These may affect the absorption rate. Models have been developed to simplify conceptualization of the many processes that take place in the interaction between an organism and a chemical substance. One of these, the multi-compartmental model, is the most used approximations to reality; the various compartments that the model is divided into are referred to as the ADME scheme: Liberation – the process of release of a drug from the pharmaceutical formulation. See IVIVC. Absorption – the process of a substance entering the blood circulation. Distribution – the dispersion or dissemination of substances throughout the fluids and tissues of the body. Metabolism – the recognition by the organism that a foreign substance is present and the irreversible transformation of parent compounds into daughter metabolites. Excretion – the removal of the substances from the body. In rare cases, some drugs irreversibly accumulate in body tissue; the two phases of metabolism and excretion can be grouped together under the title elimination.
The study of these distinct phases involves the use and manipulation of basic concepts in order to understand the process dynamics. For this reason in order to comprehend the kinetics of a drug it is necessary to have detailed knowledge of a number of factors such as: the properties of the substances that act as excipients, the characteristics of the appropriate biological membranes and the way that substances can cross them, or the characteristics of the enzyme reactions that inactivate the drug. All these concepts can be represented through mathematical formulas that have a corresponding graphical representation; the use of these models allows an understanding of the characteristics of a molecule, as well as how a particular drug will behave given information regarding some of its basic characteristics such as its acid dissociation constant and solubility, absorption capacity and distribution in the organism. The model outputs for a drug can be used in industry or in the clinical application of pharmacokinetic concepts.
Clinical pharmacokinetics provides many performance guidelines for effective and efficient use of drugs for human-health professionals and in veterinary medicine. The following are the most measured pharmacokinetic metrics: In pharmacokinetics, steady state refers to the situation where the overall intake of a drug is in dynamic equilibrium with its elimination. In practice, it is considered that steady state is reached when a time of 4 to 5 times the half-life for a drug after regular dosing is started; the following graph depicts a typical time course of drug plasma concentration and illustrates main pharmacokinetic metrics: Pharmacokinetic modelling is performed by noncompartmental or compartmental methods. Noncompartmental methods estimate the exposure to a drug by estimating the area under the curve of a concentration-time graph. Compartmental methods estimate the concentration-time graph using kinetic models. Noncompartmental methods are more versatile in that they do not assume any specific compartmental model and produce accurate results acceptable for bioequivalence studies.
The final outcome of the transformations that a drug undergoes in an organism and the rules that determine this fate depend on a number of interrelated factors. A number of functional models have been developed in order to simplify the study of pharmacokinetics; these models are based on a consideration of an organism as a number of related compartments. The simplest idea is to think of an organism as only one homogenous compartment; this monocompartmental model presupposes that blood plasma concentrations of the drug are a true reflection of the drug's concentration in other fluids or tissues and that the elimination of the drug is directly proportional to the drug's concentration in the organism. However, these models do not always reflect the real situation within an organism. For example, not all body tissues have the same blood supply, so the distribution of the drug will be slower in these tissues than in others with a better blood supply. In addition, there are some tissues (s
Death
Death is the permanent cessation of all biological functions that sustain a living organism. Phenomena which bring about death include aging, malnutrition, suicide, starvation and accidents or major trauma resulting in terminal injury. In most cases, bodies of living organisms begin to decompose shortly after death. Death – the death of humans – has been considered a sad or unpleasant occasion, due to the affection for the being that has died and the termination of social and familial bonds with the deceased. Other concerns include fear of death, anxiety, grief, emotional pain, sympathy, solitude, or saudade. Many cultures and religions have the idea of an afterlife, hold the idea of reward or judgement and punishment for past sin; the word death comes from Old English dēaþ. This comes from the Proto-Indo-European stem *dheu- meaning the "process, condition of dying"; the concept and symptoms of death, varying degrees of delicacy used in discussion in public forums, have generated numerous scientific and acceptable terms or euphemisms for death.
When a person has died, it is said they have passed away, passed on, expired, or are gone, among numerous other accepted, religiously specific and irreverent terms. Bereft of life, the dead person is a corpse, cadaver, a body, a set of remains, when all flesh has rotted away, a skeleton; the terms carrion and carcass can be used, though these more connote the remains of non-human animals. As a polite reference to a dead person, it has become common practice to use the participle form of "decease", as in the deceased; the ashes left after a cremation are sometimes referred to by the neologism cremains, a portmanteau of "cremation" and "remains". Senescence refers to a scenario when a living being is able to survive all calamities, but dies due to causes relating to old age. Animal and plant cells reproduce and function during the whole period of natural existence, but the aging process derives from deterioration of cellular activity and ruination of regular functioning. Aptitude of cells for gradual deterioration and mortality means that cells are sentenced to stable and long-term loss of living capacities despite continuing metabolic reactions and viability.
In the United Kingdom, for example, nine out of ten of all the deaths that occur on a daily basis relates to senescence, while around the world it accounts for two-thirds of 150,000 deaths that take place daily. All animals who survive external hazards to their biological functioning die from biological aging, known in life sciences as "senescence"; some organisms experience negligible senescence exhibiting biological immortality. These include the jellyfish Turritopsis dohrnii, the hydra, the planarian. Unnatural causes of death include homicide. From all causes 150,000 people die around the world each day. Of these, two thirds die directly or indirectly due to senescence, but in industrialized countries – such as the United States, the United Kingdom, Germany – the rate approaches 90%. Physiological death is now seen as a process, more than an event: conditions once considered indicative of death are now reversible. Where in the process a dividing line is drawn between life and death depends on factors beyond the presence or absence of vital signs.
In general, clinical death is neither sufficient for a determination of legal death. A patient with working heart and lungs determined to be brain dead can be pronounced dead without clinical death occurring; as scientific knowledge and medicine advance, formulating a precise medical definition of death becomes more difficult. Signs of death or strong indications that a warm-blooded animal is no longer alive are: Respiratory arrest Cardiac arrest Brain death Pallor mortis, paleness which happens in the 15–120 minutes after death Algor mortis, the reduction in body temperature following death; this is a steady decline until matching ambient temperature Rigor mortis, the limbs of the corpse become stiff and difficult to move or manipulate Livor mortis, a settling of the blood in the lower portion of the body Decomposition, the reduction into simpler forms of matter, accompanied by a strong, unpleasant odor. The concept of death is a key to human understanding of the phenomenon. There are many scientific approaches to the concept.
For example, brain death, as practiced in medical science, defines death as a point in time at which brain activity ceases. One of the challenges in defining death is in distinguishing it from life; as a point in time, death would seem to refer to the moment. Determining when death has occurred is difficult, as cessation of life functions is not simultaneous across organ systems; such determination therefore requires drawing precise conceptual boundaries between death. This is due to there being little consensus on how to define life; this general problem applies to the particular challenge of defining death in the context of medicine. It is possible to define life in terms of consciousness; when consciousness ceases, a living organism can be said to have died. One of the flaws in this approach is that there are many organisms which are alive but not conscious. Another problem is in defining consciousness, which has many different d
