WordNet

making active and effective (as a bomb)
stimulation of activity in an organism or chemical
aerate (sewage) so as to favor the growth of organisms that decompose organic matter (同)aerate
make (substances) radioactive
make active or more active; "activate an old file"
make more adsorptive; "activate a metal"
rendered active; e.g. rendered radioactive or luminescent or photosensitive or conductive
(of e.g. a molecule) made reactive or more reactive (同)excited
(military) set up and placed on active assignment; "a newly activated unit"
(of sewage) treated with aeration and bacteria to aid decomposition

PrepTutorEJDIC

活動化 / (物質の)活性化(化学反応を起こしやすくすること)
…'を'活動的にする / …‘に'放射能を与える / 〈物質〉'を'活性化する

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/10/14 00:47:08」(JST)

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Activation in (bio-)chemical sciences generally refers to the process whereby something is prepared or excited for a subsequent reaction.

Chemistry

In chemistry, "activation" refers to the reversible transition of a molecule into a nearly identical chemical or physical state, with the defining characteristic being that this resultant state exhibits an increased propensity to undergo a specified chemical reaction. Thus, activation is conceptually the opposite of protection, in which the resulting state exhibits a decreased propensity to undergo a certain reaction.

The energy of activation^[1] specifies the amount of free energy the reactants must possess (in addition to their rest energy) in order to initiate their conversion into corresponding products—that is, in order to reach the transition state for the reaction. The energy needed for activation can be quite small, and often it is provided by the natural random thermal fluctuations of the molecules themselves (i.e. without any external sources of energy).

The branch of chemistry that deals with this topic is called chemical kinetics.

Biology

Biochemistry

In biochemistry, activation, specifically called bioactivation, is where enzymes or other biologically active molecules acquire the ability to perform their biological function, such as inactive proenzymes being converted into active enzymes that are able to catalyze their substrates into products. Bioactivation may also refer to the process where inactive prodrugs are converted into their active metabolites, or the toxication of protoxins into actual toxins.

An enzyme may be reversibly or irreversibly bioactivated. A major mechanism of irreversible bioactivation is where a piece of a protein is cut off by cleavage, producing an enzyme that will then stay active. A major mechanism of reversible bioactivation is where a cofactor binds to an enzyme, which then remains active while the cofactor is bound, and stops being active when the cofactor is removed.

Immunology

In immunology, activation is the transition of leucocytes and other cell types involved in the immune system. On the other hand, deactivation is the transition in the reverse direction. This balance is tightly regulated, since a too small degree of activation causes susceptibility to infections, while, on the other hand, a too large degree of activation causes autoimmune diseases.

Activation and deactivation results from a variety of factors, including cytokines, soluble receptors, arachidonic acid metabolites, steroids, receptor antagonists, adhesion molecules, bacterial products and viral products.

Electrophysiology

Activation refers to the opening of ion channels, i.e. the conformational change that allows ions to pass.net pack for 4g

References

^ The Activation Energy of Chemical Reactions

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UpToDate Contents

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1. 肥満細胞活性化障害 mast cell activation disorders
2. 非同期性興奮と早期興奮の一般原則 general principles of asynchronous activation and preexcitation
3. 高IgM症候群 hyperimmunoglobulin m syndromes
4. 血小板生物学 platelet biology
5. 内皮：プライマー the endothelium a primer

English Journal

Cytotoxicity of (-)-vitisin B in human leukemia cells.

Wu SS, Chen LG, Lin RJ, Lin SY, Lo YE, Liang YC.SourceDepartment of Orthopedics, Shuang Ho Hospital, Taipei Medical University , Taipei , Taiwan.
Drug and chemical toxicology.Drug Chem Toxicol.2013 Jul;36(3):313-9. doi: 10.3109/01480545.2012.720990. Epub 2012 Oct 3.
Vitis thunbergii var. taiwaniana (VTT) is an indigenous Taiwanese wild grape and is used as a folk medicine in Taiwan. VTT is rich in polyphenols, especially quercetin and resveratrol derivatives, which were demonstrated to exhibit inhibitory activities against carcinogenesis and prevent some neurod
PMID 23030068

Biochemical alterations induced by acute oral doses of iron oxide nanoparticles in Wistar rats.

Kumari M, Rajak S, Singh SP, Murty US, Mahboob M, Grover P, Rahman MF.SourceToxicology Unit, Biology Division, Indian Institute of Chemical Technology , Hyderabad , India.
Drug and chemical toxicology.Drug Chem Toxicol.2013 Jul;36(3):296-305. doi: 10.3109/01480545.2012.720988. Epub 2012 Oct 1.
Magnetic iron oxide nanoparticles with appropriate surface chemistry have been widely used with potential new applications in biomedical industry. Therefore, the aim of this study was to assess the size-, dose-, and time-dependent effects, after acute oral exposure to iron oxide-30 NP (Fe(2)O(3)-30)
PMID 23025823

Oral toxicity and pharmacokinetic studies of SHetA2, a new chemopreventive agent, in rats and dogs.

Kabirov KK, Kapetanovic IM, Benbrook DM, Dinger N, Mankovskaya I, Zakharov A, Detrisac C, Pereira M, Martín-Jiménez T, Onua E, Banerjee A, van Breemen RB, Nikolić D, Chen L, Lyubimov AV.SourceToxicology Research Laboratory, Department of Pharmacology, University of Illinois at Chicago , Chicago, Illinois , USA.
Drug and chemical toxicology.Drug Chem Toxicol.2013 Jul;36(3):284-95. doi: 10.3109/01480545.2012.710632. Epub 2012 Sep 5.
SHetA2 is a heteroarotinoid that has shown selective inhibition of cancer cell growth and an induction of apoptosis without activation of nuclear retinoic acid receptors. In the rat study, SHetA2 was administered in 1% aqueous methylcellulose/0.2% Tween 80 by oral gavage at 0, 100, 500, and 2,000
PMID 22947079

Insulin resistance is increased in alopecia areata patients.

Karadag AS, Ertugrul DT, Bilgili SG, Takci Z, Tutal E, Yilmaz H.SourceFaculty of Medicine, Department of Dermatology, Yuzuncu Yil University, Van, Turkey. drayserem@yahoo.com
Cutaneous and ocular toxicology.Cutan Ocul Toxicol.2013 Jun;32(2):102-6. doi: 10.3109/15569527.2012.713418. Epub 2012 Aug 24.
Increased insulin resistance (IR) has been found in androgenetic alopecia in several studies. However, IR has not been investigated in alopecia areata (AA). We aimed to investigate IR in AA patients and the controls. Anthropometric and demographic data were obtained from 51 AA patients and 36 contro
PMID 22916967

Japanese Journal

Influence of Microstructure on Fatigue Fracture Characteristics of Al2O3

広島工業大学研究紀要 33, 67-74, 36192-00-00
NAID 120005403235

Cation Measurements and Gene Expression Analysis Suggest Tomato Leaf Marginal Necrosis is Caused by a Jasmonate Signal Induced by K<sup>+</sup> Starvation in the Tip Region of Leaflets