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1 天前 · Fentanyl is a highly potent synthetic piperidine opioid primarily used as an analgesic. It is 20 to 40 times more potent than heroin and 100 times more potent than morphine; [8] its primary clinical utility is in pain management for cancer patients and those recovering from painful surgeries. [9] [10] Fentanyl is also used as a sedative. [11]
5 天前 · Human papillomavirus infection ( HPV infection) is caused by a DNA virus from the Papillomaviridae family. [5] Many HPV infections cause no symptoms and 90% resolve spontaneously within two years. [1] In some cases, an HPV infection persists and results in either warts or precancerous lesions. [2] These lesions, depending on the site affected ...
1 天前 · Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. Dopamine constitutes about 80% of the catecholamine content in the brain. It is an amine synthesized by removing a carboxyl group from ...
2 天前 · Ammonia is a colourless gas with a characteristically pungent smell.It is lighter than air, its density being 0.589 times that of air.It is easily liquefied due to the strong hydrogen bonding between molecules. Gaseous ammonia turns to a colourless liquid, which boils at −33.1 C (−27.58 F), and freezes to colourless crystals at −77.7 C (−107.86 F).
2 天前 · Antony John Blinken (born April 16, 1962) is an American lawyer and diplomat currently serving as the 71st United States secretary of state. He previously served as deputy national security advisor from 2013 to 2015 and deputy secretary of state from 2015 to 2017 under President Barack Obama. [1] Blinken was previously national security advisor ...
2 天前 · Principal component analysis (PCA) is a linear dimensionality reduction technique with applications in exploratory data analysis, visualization and data preprocessing. The data is linearly transformed onto a new coordinate system such that the directions (principal components) capturing the largest variation in the data can be easily identified.
2 天前 · Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, lead, and flerovium are below it. It is relatively unreactive ...
