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Placebo-controlled Study
Placebo-controlled studies are a way of testing a medical therapy in which, in addition to a group of subjects that receives the treatment to be evaluated, a separate control group receives a sham "placebo" treatment which is specifically designed to have no real effect. Placebos are most commonly used in blinded trials, where subjects do not know whether they are receiving real or placebo treatment. Often, there is also a further "natural history" group that does not receive any treatment at all. The purpose of the placebo group is to account for the placebo effect, that is, effects from treatment that do not depend on the treatment itself. Such factors include knowing one is receiving a treatment, attention from health care professionals, and the expectations of a treatment's effectiveness by those running the research study. Without a placebo group to compare against, it is not possible to know whether the treatment itself had any effect. Patients frequently show improvement e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cebocap
A placebo ( ) is a substance or treatment which is designed to have no therapeutic value. Common placebos include inert tablets (like sugar pills), inert injections (like saline), sham surgery, and other procedures. In general, placebos can affect how patients perceive their condition and encourage the body's chemical processes for relieving pain and a few other symptoms, but have no impact on the disease itself. Improvements that patients experience after being treated with a placebo can also be due to unrelated factors, such as regression to the mean (a statistical effect where an unusually high or low measurement is likely to be followed by a less extreme one). The use of placebos in clinical medicine raises ethical concerns, especially if they are disguised as an active treatment, as this introduces dishonesty into the doctor–patient relationship and bypasses informed consent. While it was once assumed that this deception was necessary for placebos to have any effect, ther ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crossover Studies
In medicine, a crossover study or crossover trial is a longitudinal study in which subjects receive a sequence of different treatments (or exposures). While crossover studies can be observational studies, many important crossover studies are controlled experiments, which are discussed in this article. Crossover designs are common for experiments in many scientific disciplines, for example psychology, pharmaceutical science, and medicine. Randomized, controlled crossover experiments are especially important in health care. In a randomized clinical trial, the subjects are randomly assigned to different arms of the study which receive different treatments. When the trial has a repeated measures design, the same measures are collected multiple times for each subject. A crossover trial has a repeated measures design in which each patient is assigned to a sequence of two or more treatments, of which one may be a standard treatment or a placebo. Nearly all crossover are designed to hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Citrus Fruit
''Citrus'' is a genus of flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, lemons, grapefruits, pomelos, and limes. The genus ''Citrus'' is native to South Asia, East Asia, Southeast Asia, Melanesia, and Australia. Various citrus species have been used and domesticated by indigenous cultures in these areas since ancient times. From there its cultivation spread into Micronesia and Polynesia by the Austronesian expansion (c. 3000–1500 BCE); and to the Middle East and the Mediterranean (c. 1200 BCE) via the incense trade route, and onwards to Europe and the Americas. History Citrus plants are native to subtropical and tropical regions of Asia, Island Southeast Asia, Near Oceania, and northeastern Australia. Domestication of citrus species involved much hybridization and introgression, leaving much uncertainty about when and where domestication first happened. A genomic, phylogeni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HMS Salisbury
Seven ships of the Royal Navy have been named HMS ''Salisbury'' after the city of Salisbury in Wiltshire: * was a 48-gun fourth rate, launched in 1698 and captured by the French in 1703. She was subsequently recaptured in 1708 and renamed ''Salisbury Prize'', and later renamed ''Preston'' in 1716. She was broken up in 1749. * was a 54-gun fourth rate launched in 1707, rebuilt in 1726 and sold in 1749. * was a 50-gun fourth rate launched in 1746 and condemned in 1761. * was a 50-gun fourth rate launched in 1769 and grounded and surrendered to the Spanish in 1796 at Avache Island, Santo Domingo. * was a 58-gun fourth rate launched in 1814 and sold in 1837. * was originally the American destroyer , transferred to the Royal Navy in 1940. She was lent to the Royal Canadian Navy in 1942 and sold to them in 1944. * was a or Type 61 aircraft direction frigate A frigate () is a type of warship. In different eras, the roles and capabilities of ships classified as frigates hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship's Doctor
A naval surgeon, or less commonly ship's doctor, is the person responsible for the health of the ship's company aboard a warship. The term appears often in reference to Royal Navy's medical personnel during the Age of Sail. Ancient uses Specialised crew members capable of providing medical care have been a feature of military vessels for at least two thousand years. The second-century Roman Navy under Emperor Hadrian included a surgeon aboard each of its triremes, with the position earning twice a regular officer's pay. Royal Navy During the Age of Sail, the Royal Navy carried trained medical officers aboard its warships, who usually learned their trade before coming on board ship. They were generally called surgeons. The Navy Board qualified surgeons through an examination at the Barber-Surgeons' Company and they were responsible to the Sick and Wounded Board under the Navy Board. Surgeons were required to keep two logbooks detailing treatments and procedures carried out under ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Lind (physician)
James Lind (4 October 1716 – 13 July 1794) was a Scottish doctor. He was a pioneer of naval hygiene in the Royal Navy. By conducting one of the first ever clinical trials, he developed the theory that citrus fruits cured scurvy. Lind argued for the health benefits of better ventilation aboard naval ships, the improved cleanliness of sailors' bodies, clothing and bedding, and below-deck fumigation with sulphur and arsenic. He also proposed that fresh water could be obtained by distilling sea water. His work advanced the practice of preventive medicine and improved nutrition. Early life Lind was born in Edinburgh, Scotland, in 1716 into a family of merchants, then headed by his father, James Lind. He had an elder sister. He was educated at the High School in Edinburgh. In 1731 he began his medical studies as an apprentice of George Langlands, a fellow of the Incorporation of Surgeons which preceded the Royal College of Surgeons of Edinburgh. In 1739, he entered the Navy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Lind
James Lind (4 October 1716 – 13 July 1794) was a Scottish doctor. He was a pioneer of naval hygiene in the Royal Navy. By conducting one of the first ever clinical trials, he developed the theory that citrus fruits cured scurvy. Lind argued for the health benefits of better ventilation aboard naval ships, the improved cleanliness of sailors' bodies, clothing and bedding, and below-deck fumigation with sulphur and arsenic. He also proposed that fresh water could be obtained by distilling sea water. His work advanced the practice of preventive medicine and improved nutrition. Early life Lind was born in Edinburgh, Scotland, in 1716 into a family of merchants, then headed by his father, James Lind. He had an elder sister. He was educated at the High School in Edinburgh. In 1731 he began his medical studies as an apprentice of George Langlands, a fellow of the Incorporation of Surgeons which preceded the Royal College of Surgeons of Edinburgh. In 1739, he entered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Niacin (substance)
Niacin, also known as nicotinic acid, is an organic compound and a form of vitamin B3, an essential human nutrient. It can be manufactured by plants and animals from the amino acid tryptophan. Niacin is obtained in the diet from a variety of whole and processed foods, with highest contents in fortified packaged foods, meat, poultry, red fish such as tuna and salmon, lesser amounts in nuts, legumes and seeds. Niacin as a dietary supplement is used to treat pellagra, a disease caused by niacin deficiency. Signs and symptoms of pellagra include skin and mouth lesions, anemia, headaches, and tiredness. Many countries mandate its addition to wheat flour or other food grains, thereby reducing the risk of pellagra. The amide derivative nicotinamide (niacinamide) is a component of the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP+). Although niacin and nicotinamide are identical in their vitamin activity, nicotina ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psilocybin
Psilocybin ( , ) is a naturally occurring psychedelic prodrug compound produced by more than 200 species of fungi. The most potent are members of the genus ''Psilocybe'', such as '' P. azurescens'', '' P. semilanceata'', and '' P. cyanescens'', but psilocybin has also been isolated from about a dozen other genera. Psilocybin is itself biologically inactive but is quickly converted by the body to psilocin, which has mind-altering effects similar, in some aspects, to those of LSD, mescaline, and DMT. In general, the effects include euphoria, visual and mental hallucinations, changes in perception, a distorted sense of time, and perceived spiritual experiences. It can also cause adverse reactions such as nausea and panic attacks. Imagery found on prehistoric murals and rock paintings of modern-day Spain and Algeria suggests that human usage of psilocybin mushrooms predates recorded history. In Mesoamerica, the mushrooms had long been consumed in spiritual and div ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psychedelic Drug
Psychedelics are a subclass of hallucinogenic drugs whose primary effect is to trigger non-ordinary states of consciousness (known as psychedelic experiences or "trips").Pollan, Michael (2018). ''How to Change Your Mind: What the New Science of Psychedelics Teaches Us About Consciousness, Dying, Addiction, Depression, and Transcendence'' Sometimes, they are called classic hallucinogens, serotonergic hallucinogens, or serotonergic psychedelics, and the term ''psychedelics'' is used more broadly to include all hallucinogens; this article uses the narrower definition of ''psychedelics''. Psychedelics cause specific psychological, visual, and auditory changes, and often a substantially altered state of consciousness.Leary, Timothy; Metzner, Ralph (1964). ''The Psychedelic Experience: A Manual Based on The Tibetan Book of the Dead'' Psychedelic states are often compared to meditative, psychodynamic or transcendental types of alterations of mind. The "classical" psychedelics, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blinded Experiment
In a blind or blinded experiment, information which may influence the participants of the experiment is withheld until after the experiment is complete. Good blinding can reduce or eliminate experimental biases that arise from a participants' expectations, observer's effect on the participants, observer bias, confirmation bias, and other sources. A blind can be imposed on any participant of an experiment, including subjects, researchers, technicians, data analysts, and evaluators. In some cases, while blinding would be useful, it is impossible or unethical. For example, it is not possible to blind a patient to their treatment in a physical therapy intervention. A good clinical protocol ensures that blinding is as effective as possible within ethical and practical constraints. During the course of an experiment, a participant becomes unblinded if they deduce or otherwise obtain information that has been masked to them. For example, a patient who experiences a side effect may corr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marsh Chapel Experiment
The Marsh Chapel Experiment, also called the "Good Friday Experiment", was a 1962 experiment conducted on Good Friday at Boston University's Marsh Chapel. Walter N. Pahnke, a graduate student in theology at Harvard Divinity School, designed the experiment under the supervision of Timothy Leary, Richard Alpert, and the Harvard Psilocybin Project. Pahnke's experiment investigated whether psilocybin (the active principle in psilocybin mushrooms) would act as a reliable entheogen in religiously predisposed subjects. Experiment Prior to the Good Friday service, twenty graduate degree divinity student volunteers from the Boston area were randomly divided into two groups. In a double-blind experiment, half of the students received psilocybin, while a control group received a large dose of niacin. Niacin produces clear physiological changes and thus was used as an active placebo. In at least some cases, those who received the niacin initially believed they had received the psychoactive d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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