chemical


Also found in: Dictionary, Thesaurus, Legal, Acronyms, Idioms, Encyclopedia, Wikipedia.
Related to chemical: chemical pregnancy, chemical peel

chemical

 [kem´ĭ-k'l]
1. pertaining to chemistry.
2. a substance composed of chemical elements, or obtained by chemical processes.

chem·i·cal

(kem'i-kăl),
Relating to chemistry.

chemical

/chem·i·cal/ (kem´ĭ-k'l)
1. pertaining to chemistry.
2. a substance composed of chemical elements, or obtained by chemical processes.

chemical

[kem′əkəl]
Etymology: Gk, chemeia, alchemy
1 n, a substance composed of chemical elements or a substance produced by or used in chemical processes.
2 adj, pertaining to chemistry.

Pearl Index

Obstetrics A formula that allows comparison of the efficacy of contraceptive methods, calculated as the pregnancy rate in population divided by 100 yrs of exposure. See Breast feeding, Coitus interruptus, Condoms, Morning-after pill, Contraception, Natural family planning, Norplant, Rhythm method, RU 486.
Pearl index–pregnancies/100 years of use
Physiologic 15-30/100 years: Coitus interruptus, natural family planning (rhythm or safe period), eg calendar method, evaluation of cervical mucosa or temperature, breast feeding
Chemical 15-20/100 years: Contraceptive sponges
Barrier 2-20/100 years: Intrauterine devices, condoms
Hormonal 1-3/100 years
Surgical << 1/100 years: Ligation of fallopian tubes, vas deferens  

chem·i·cal

(kem'i-kăl)
Relating to chemistry.

chemical

1. pertaining to chemistry.
2. a substance composed of chemical elements, or obtained by chemical processes. See also toxin.

chemical adjuvant
a chemical added to another to improve its activity. For example, mineral gels added to vaccines. May also be a chemical added to feed to improve digestion, e.g. monensin in ruminants. These are more commonly referred to as additives. See also adjuvant.
agricultural chemical
chemical used in agriculture. Includes pesticides, anthelmintics, fertilizers, algaecides, herbicides, soil fumigants and the like.
chemical environment
that part of the animals' environment that is composed of chemicals. For farm livestock this includes fertilizers, defoliants, worm drenches, insect sprays, adjuvants to feed. For companion animals see household chemical (below).
household chemical
the roster of chemicals that one can expect to find in the average household. Includes insect sprays and repellents, snail bait, rodenticide, garden sprays, human medicines and the like.
chemical pneumonitis
results from aspiration of gastric acids.
chemical senses
see olfaction (2), taste.
chemical shearing
causing the fleece of sheep to be shed by the administration of a chemical substance to the sheep. Cyclophosphamide and mimosine have been used experimentally but there is no commercially available system.
chemical spoilage
occurs in preserved foods, especially canned ones. Is usually the result of interaction between the contents and an imperfect container. There may be gas produced, e.g. hydrogen swells, or discoloration of the tin.
chemical warfare
agents used include: (1) systemic poisons, e.g. hydrocyanic acid; (2) lung irritants, e.g. chlorine, phosgene; (3) lacrimators (weeping stimulators), e.g. CN, CAP, CS; (4) sternutators (sneeze stimulators); (5) vesicants, e.g. mustards, nitrogen mustards, arsenic mustards and nettle gases; (6) nerve gases, e.g. organophosphorus compounds.

Patient discussion about chemical

Q. How do you know when depression is chemical or situational? I've been feeling frustrated lately and while I think I show some signs of depression I think it is more a feeling down because of recent changes in my life. Every time I have seen a professional they all want to start me on some drug and having really seen no improvement over the years I swore off them years ago. When is it depression or "My life sucks right now"?

A. Thank you Johanna for sharing this with us.

Q. ADHD medications work on these brain chemicals? Hope you all know about the different types of brain chemicals, so the ADHD medications work on these brain chemicals?

A. Yes Alexzander. The active ingredients in the common ADHD medications are amphetamines. The amphetamines artificially increase the amount of certain neurotransmitters in the brain, speeding up the brain (thus the term “speed” for amphetamines). This makes the frontal area more active, at least while the drug is acting.

Q. How do you tell the difference between chemical burns, and burns from fire? Please don't spare on gross words i would like to know everything there is to burns.

A. Here is a ton of info on both-
http://en.wikipedia.org/wiki/Chemical_burn
http://en.wikipedia.org/wiki/Burn_%28injury%29

More discussions about chemical
References in periodicals archive ?
According to Irenee Philippe, director of technology, Ciba Specialty Chemicals, Suffolk, Virginia, competitive advantage is achieved when performance chemical programs allow newer machines to optimize their operating windows with maximum return on investment (ROI) while enabling older paper machines to operate more competitively without major capital investment.
Miller contends that addiction and chemical intolerance represent divergent physiologic responses to a shared underlying disease mechanism she calls toxicant-induced loss of tolerance (TILT).
Bush has given primary responsibility for overseeing security improvements in the chemical industry to the EPA.
Treatment with the chemicals shifted the structure of the algal communities compared with the untreated algae communities, the researchers report in an upcoming Environmental Science and Technology.
There have been concerted efforts within the chemical industry during the past three to four years to try to prevent Y2K problems.
It has formed numerous strategic partnerships with other chemical companies over the last few years, but few analysts have been able to define a coherent strategy for growth.
According to the EPA's perverse logic, this triumph of chemical recycling is reported to the public under TRI regulations as industry "waste.
The chemical inventory management system approach is to track each chemical container, from the point of ordering (cradle) to the point of disposal (grave), on a mass balance basis.
The Japanese chemicals, materials, and foods industry is driven by strong external demand, largely aided by the country's proximity to high-growth countries such as China and India.
Another method might include changing chemical treatment programs to those that offer advantages with regard to system hydraulics, which can ultimately reduce the volume to be treated and therefore the chemical use.
Both Auer and Walls note there could be a variety of reasons for the chemical industry not doing this testing voluntarily.
The law would also bar police, firefighters, local emergency planners, and federal, state, and local officials from discussing chemical hazards with their communities.