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In organic chemistry, Keller's reagent is a mixture of anhydrous (glacial) acetic acid, concentrated sulfuric acid, and small amounts of ferric chloride, used to detect alkaloids. Keller's reagent can also be used to detect other kinds of alkaloids via reactions in which it produces products with a wide range of colors.
Keller's reagent can refer to two different reagents: Keller's reagent (metallurgy), used to etch aluminum alloys; Keller's reagent (organic), used to detect alkaloids
In metallurgy, Keller's reagent is a mixture of nitric acid, hydrochloric acid, and hydrofluoric acid, used to etch aluminum alloys to reveal their grain boundaries and orientations. [1] It is also sometimes called Dix–Keller reagent, after E. H. Dix, Jr., and Fred Keller of the Aluminum Corporation of America, who pioneered the use of this ...
This is because Escherichia coli is the most likely causative bacterium, and may be sensitive to that combination antibiotic. [2] However, bacteria can be resistant to several classes of antibiotics. [2] This resistance might be because a type of bacteria has intrinsic resistance to some antibiotics, [2] because of resistance following past ...
Cross-resistance can take place between compounds that are chemically similar, like antibiotics within similar and different classes. [9] That said, structural similarity is a weak predictor of antibiotic resistance, and does not predict antibiotic resistance at all when aminoglycosides are disregarded in the comparison. [10]
This strain is further increased by fusion to a second ring, as found in most β-lactam antibiotics. This trend is due to the amide character of the β-lactam being reduced by the aplanarity of the system. The nitrogen atom of an ideal amide is sp 2-hybridized due to resonance, and sp 2-hybridized atoms have trigonal planar bond geometry.
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Thus ESBLs confer multi-resistance to these antibiotics and related oxyimino-beta lactams. In typical circumstances, they derive from genes for TEM-1, TEM-2, or SHV-1 by mutations that alter the amino acid configuration around the active site of these β-lactamases. A broader set of β-lactam antibiotics are susceptible to hydrolysis by these ...