Chemical Modification of Wood (I): Acetic Anhydride Modification

2006 ◽  
pp. 45-76 ◽  
Keyword(s):  
Acetic Anhydride ◽  
Chemical Modification

Chemical modification of erythrocyte membranes: Double labeling with acetic anhydride

1972 ◽  
Vol 8 (1) ◽  
pp. 65-81 ◽  
Author(s):  
Kermit L. Carraway ◽  
David Kobylka ◽  
Joan Summers ◽  
Coralie A. Carraway
Keyword(s):  
Acetic Anhydride ◽  
Chemical Modification ◽  
Erythrocyte Membranes ◽  
Double Labeling

scholarly journals Effect of chemical modification on dimensional stability of Pinus radiata D. Don using acetic anhydride

2020 ◽  
Vol 66 (No. 5) ◽  
pp. 208-217
Author(s):  
Sanjeet Kumar Hom ◽  
Sauradipta Ganguly ◽  
Yasir Ullah Bhoru ◽  
Ajmal Samani
Keyword(s):  
Acetic Anhydride ◽  
Chemical Modification ◽  
Water Absorption ◽  
Pinus Radiata ◽  
Dimensional Stability ◽  
Untreated Wood ◽  
Treatment Methods ◽  
Cell Method ◽  
Full Cell ◽  
Swelling Coefficient

Chemical modification is used to efficiently improve some properties of wood to make it suitable for specific end uses. Modification using acetic anhydride (AA) is found suitable to make the wood more stable dimensionally. Pinus radiata wood samples treated with pyridine catalyzed AA were exposed to four different treatment methods comprising vacuum dipping and full cell method (cured with and without chemical). Physical properties like weight percentage gain (WPG), bulking coefficient, swelling coefficient (S) due to the chemical, water absorption and anti-swelling efficiency (ASE) were assessed for a comparative analysis. Results indicated a significant reduction in water absorption of acetylated wood. The swelling coefficients of all the treatments were found in the range of 3.86–4.96, which was twice to three times less than in the control (11.72) attributing 55–64% improvement in dimensional stability. Samples treated with full cell method and cured in the chemical mixture showed minimum swelling coefficient and best anti-swelling efficiency. All the four treatment methods chosen for the study returned significantly better dimensional stability as compared to untreated wood.

scholarly journals Chemical modification of sarcoplasmic reticulum. Stimulation of Ca2+ release

1986 ◽  
Vol 240 (2) ◽  
pp. 509-517 ◽  
Author(s):  
V Shoshan-Barmatz
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Acetic Anhydride ◽  
Atpase Activity ◽  
Chemical Modification ◽  
Amino Groups ◽  
Reactive Group ◽  
Rapid Release ◽  
Sarcoplasmic Reticulum Membrane ◽  
Positively Charged ◽  
Stimulation Of

Pretreatment of sarcoplasmic membranes with acetic or maleic anhydrides, which interact principally with amino groups, resulted in an inhibition of Ca2+ accumulation and ATPase activity. The presence of ATP, ADP or adenosine 5′-[beta, gamma-imido]triphosphate in the modification medium selectively protected against the inactivation of ATPase activity by the anhydride but did not protect against the inhibition of Ca2+ accumulation. Acetic anhydride modification in the presence of ATP appeared to increase specifically the permeability of the sarcoplasmic reticulum membrane to Ca2+ but not to sucrose, Tris, Na+ or Pi. The chemical modification stimulated a rapid release of Ca2+ from sarcoplasmic reticulum vesicles passively or actively loaded with calcium, from liposomes reconstituted with the partially purified ATPase fraction but not from those reconstituted with the purified ATPase. The inactivation of Ca2+ accumulation by acetic anhydride (in the presence of ATP) was rapid and strongly pH-dependent with an estimated pK value above 8.3 for the reactive group(s). The negatively charged reagents pyridoxal 5-phosphate and trinitrobenzene-sulphonate, which also interact with amino groups, did not stimulate Ca2+ release. Since these reagents do not penetrate the sarcoplasmic reticulum membranes, it is proposed that Ca2+ release is promoted by modification of internally located, positively charged amino group(s).

scholarly journals Chemical modification studies on a lectin from winged-bean [Psophocarpus tetragonolobus (L.) DC] tubers

1988 ◽  
Vol 254 (2) ◽  
pp. 351-357 ◽  
Author(s):  
M S Shet ◽  
M Madaiah
Keyword(s):  
Acetic Anhydride ◽  
Chemical Modification ◽  
Succinic Anhydride ◽  
Structural Changes ◽  
Dicarboxylic Acids ◽  
Winged Bean ◽  
Amino Groups ◽  
Reductive Methylation ◽  
Tryptophan Residues ◽  
Haemagglutinating Activity

The effect of chemical modification on a D(+)-galactose-specific lectin isolated from winged-bean tubers was investigated to identify the type of amino acid involved in its haemagglutinating activity. Various anhydrides of dicarboxylic acids, such as acetic anhydride, succinic anhydride, maleic anhydride and citraconic anhydride, modified 57-68% of the amino groups of the winged-bean tuber lectin. Treatment with N-acetylimidazole modified only 45% of the total amino groups. Reductive methylation of free amino groups modified 57% of the amino groups. Modification of the amino groups of the lectin by acetic anhydride and succinic anhydride did not lead to any significant change in the haemagglutinating activity (greater than or equal to 75% active). However, citraconylation and maleylation of the lectin led to a significant decrease in the haemagglutinating activity (less than or equal to 20% active). Acetylation and succinylation (3-carboxypropionylation) of the lectin led to a decrease in the pI value of the native lectin from approx. 9.5 to approx. 4.5. Treatment of the lectin with N-bromosuccinimide led to the modification of two and four tryptophan residues per molecule in the absence and in the presence of 8 M-urea respectively. The immunological identity of all the modified lectin preparations showed no gross structural changes except the lectin modified with N-bromosuccinimide in the presence of urea at pH 4.0.

DETERMINATION OF ALDOSTERONE AND DEOXYCORTICOSTERONE IN PLASMA USING 3H-ACETIC ANHYDRIDE AND VAPOUR PHASE ACETYLATION

1969 ◽  
Vol 61 (1_Suppl) ◽  
pp. S12 ◽  
Author(s):  
V. H. T. James ◽  
A. E. Rippon ◽  
M. L. Arnold
Keyword(s):  
Acetic Anhydride ◽  
Vapour Phase

Photoconductivity in Vacuum Deposited Films of Silicon-Based Polymers

1996 ◽  
Vol 444 ◽  
Author(s):  
H. Okumoto ◽  
M. Shimomura ◽  
N. Minami ◽  
Y. Tanabe
Keyword(s):  
Charge Transfer ◽  
Chemical Modification ◽  
Electronic Transport ◽  
Hole Transport ◽  
Electron Acceptors ◽  
Oxygen Atmosphere ◽  
Dangling Bonds ◽  
Silicon Based ◽  
Deposited Films

AbstractSilicon-based polymers with σconjugated electrons have specific properties; photoreactivity for microlithography and photoconductivity for hole transport materials. To explore the possibility of combining these two properties to develop photoresists with electronic transport capability, photoconductivity of polysilanes is investigated in connection with their photoinduced chemical modification. Increase in photocurrent is observed accompanying photoreaction of poly(dimethylsilane) vacuum deposited films. This increase is found to be greatly enhanced in oxygen atmosphere. Such changes of photocurrent can be explained by charge transfer to electron acceptors from Si dangling bonds postulated to be formed during photoreaction.

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