The effect of tris(hydroxymethyl)aminomethane (Tris) buffer on outer membrane permeability was examined in a smooth strain (D280) and in a heptose-deficient lipopolysaccharide strain (F515) of Escherichia coli O8. Tris buffer (pH 8.00) was found to increase outer membrane permeability on the basis of an increased Vo of whole-cell alkaline phosphatase activity and on the basis of sensitivity to ...

conclusion using standard imaging parameters, each mri sequence reaches its maximum si in a specific contrast concentration, which is highest in se and least in ir in a comparison between se, fse and ir sequences. results this study shows that maximum si will appear at different ranges in different sequences. the maximum si can be seen at concentrations of 5.95, 4.96 and 3.98mmol/l for se, fse ...

semen from six adult male black bengal goats (capra hircus) was collected to compare the fresh and frozen-thawed semen quality and investigate its relationship with the fertility. each collected samples was divided into two parts: one part of semen was used as fresh and another part was filled into 0.50 ml straws, sealed, cooled (5 ˚c) and equilibrated for freezing.in both cases, semen was dilu...

the present study was aimed to test the efficacy of adding vitamins c or e to tris-fructose-egg yolk diluent to increase awassi ram sperm storage period at 5 ˚c. semen samples from six mature awassi rams were used in this study. the semen samples were diluted by tris-glucose-egg yolk. diluted semen sample was divided into three parts. the first part was added with 0.9 mg ml-1 vitamin c, the sec...

The tris(pentafluoroethyl)silanol, Si(C2F5)3OH, flashes out of the shadows silanol derivatives in cover image, paving way to its disiloxane and disilanolate. Oxidation tris(pentafluoroethyl)silane, Si(C2F5)3H, with NO2 provides which readily condenses (C2F5)3SiOSi(C2F5)3. Deprotonation situ generated Si(C2F5)3OH yields disilanolate [{Si(C2F5)3O}2]2− underlining formally Lewis amphoteric charact...