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svet-max [94.6K]
3 years ago
14

An early method of evaluating the effectiveness of an antimicrobial chemical is to compare it's effectiveness to that of

Biology
1 answer:
Nimfa-mama [501]3 years ago
7 0

Answer:

The effectiveness of chemical disinfectants has historically been compared to phenol.

Explanation:

The effectiveness of a disinfectant or antiseptic can be determined in a number of ways. Historically, a chemical agent’s effectiveness was often compared with that of phenol, the first chemical agent used by Joseph Lister. In 1903, British chemists Samuel Rideal (1863–1929) and J. T. Ainslie Walker (1868–1930) established a protocol to compare the effectiveness of a variety of chemicals with that of phenol, using as their test organisms Staphylococcus aureus (a gram-positive bacterium) and Salmonella enterica serovar Typhi (a gram-negative bacterium). They exposed the test bacteria to the antimicrobial chemical solutions diluted in water for 7.5 minutes. They then calculated a phenol coefficient for each chemical for each of the two bacteria tested. A phenol coefficient of 1.0 means that the chemical agent has about the same level of effectiveness as phenol. A chemical agent with a phenol coefficient of less than 1.0 is less effective than phenol. An example is formalin, with phenol coefficients of 0.3 (S. aureus) and 0.7 (S. enterica serovar Typhi). A chemical agent with a phenol coefficient greater than 1.0 is more effective than phenol, such as chloramine, with phenol coefficients of 133 and 100, respectively. Although the phenol coefficient was once a useful measure of effectiveness, it is no longer commonly used because the conditions and organisms used were arbitrarily chosen.

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Answer:

<u>A focal infection</u> is a small region of infection, from where the pathogen can move to other areas of the body to cause a secondary infection.      

Explanation:

The focal infection theory is a theory that states that many chronic diseases (such as cancer, arthritis, mental illness) are caused by a focal infection. A focal infection is a small region of infection or a localized infected region, which can lead to a secondary infection at a site, which is susceptible to infections. Examples of such focal regions are nasal sinuses, kidney, gall bladder, liver, etc.

<u>Therefore,</u><u> a focal infection </u><u>can be defined as a small region of infection, from where the pathogen can move to other areas of the body to cause a secondary infection</u>.      

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3 years ago
sub-saharan africans show the largest genetic diversity of any human population. this is likely to have resulted from a. a small
boyakko [2]

accumulations of genetic mutations over time.

Genetic and epigenetic changes compound over time to cause cancer. While aging and chronic inflammation are the major causes of epigenetic changes, carcinogenic substances, UV radiation, and other conditions can also cause genetic changes. Our prior exposure levels and life history are reflected in the accumulation and patterns of changes in normal cells. The majority of accumulated changes are regarded as passengers, although they are linked to cancer drivers as they accumulate. Although only hypothesized for genetic changes, this has been demonstrated for aberrant DNA methylation. However, modern technology has made it possible to assess uncommon point mutations, and research has revealed that the rates of their accumulation do actually correspond with cancer risk.

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stellarik [79]

Answer:

Native conformation

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