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31.
P.M.?Kosaka Y.?Kawano M.C.?Salvadori D.F.S.?PetriEmail author 《Cellulose (London, England)》2005,12(4):351-359
The adsorption of cellulose acetate (CA), cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB) from solutions
prepared in acetone onto silicon wafers led to ultrathin films, which were characterized by ellipsometry, atomic force microscopy
(AFM) and contact angle measurements. The polysaccharides films were characterized in the air just after their formation and
after annealing at temperatures higher than their glass transition temperature or melt temperature. The films thickness close
to 2 nm and surface roughness did not vary significantly upon annealing. AFM images revealed the presence of small clumps
dispersed on a homogeneous layer, which covered completely the Si wafers. Such topographic details were also observed after
annealing. However, upon annealing the films surfaces changed from hydrophilic to hydrophobic, evidencing molecular re-orientation
at the solid–air interface. The adhesion of bovine serum albumin (BSA) and lipase onto the cellulose esters films was quantified
in order to evaluate the possibility of applying such films as selective support for biomolecules. 相似文献
32.
33.
HAGINAKA Jun 《色谱》2002,20(6):508-518
The author has prepared novel liquid chromatography (LC) packing materials for pharmaceutical and biomedical analysis. Those include LC packing materials for direct serum injection assays of drugs and their metabolites, LC packing materials for resolution of enantiomeric drugs, and uniformly sized molecularly imprinted polymers for drugs and their metabolites. 相似文献
34.
35.
微量元素对人体健康的影响 总被引:15,自引:2,他引:15
阐述了微量元素的生理作用以及对人体健康的影响和微量元素平衡的重要性,对临床医学及日常生活有一定的参考价值。 相似文献
36.
Human serum is routinely measured for total calcium content in clinical studies. A definitive high-accuracy and low-uncertainty method is required for reference measurements to underpin medical diagnoses. This study presents a novel octopole collision cell ICP-MS, high-accuracy, methodology and comparison of that technique with double-focusing sector field ICP-MS and an ICP-OES method. Double-matched isotope dilution mass spectrometry (IDMS) was employed for ICP-MS techniques and an exact matching bracketing technique using scandium as an internal standard was used for ICP-OES analysis. Medium resolution mode was utilised for double-focusing sector field ICP-MS analysis to resolve the dominant interferences on the 44Ca/42Ca isotope pair. Hydrogen reaction gas was employed to chemically resolve a number of polyatomic interferences predominantly through charge transfer reactions in the octopole collision cell. Comparison data presented for NIST CRM 909b human serum analysis from all three techniques demonstrates highest accuracy (99.6%) and lowest uncertainty (1.1%) for octopole collision cell ICP-MS. Data from ICP-OES using a non-IDMS technique produces comparably accurate data and low-uncertainties. The much higher total expanded uncertainties for double-focusing sector field ICP-MS compared with octopole collision cell data are explained by lower precision on the measurement of the 44Ca/42Ca isotope ratio. Data for octopole collision cell ICP-MS submitted for an international blind trial comparison (CCQM K-14) demonstrated excellent agreement with the mean of all participants with a low expanded uncertainty. 相似文献
37.
荧光法研究Ge-132对牛血清白蛋白Maillard反应的抑制作用 总被引:2,自引:0,他引:2
人体内氨基酸及蛋白质的非酶糖化反应(Maillard反应)与糖尿病及其并发症的关系已经引起广泛注意[1].有机锗化合物β-羧乙基锗倍半氧化物(Ge-132)具有预防糖尿病及调节糖代谢的作用[2]. 相似文献
38.
Fluorometric investigation of the interaction of bovine serum albumin with surfactants and 6-mercaptopurine 总被引:2,自引:0,他引:2
Hu YJ Liu Y Jiang W Zhao RM Qu SS 《Journal of photochemistry and photobiology. B, Biology》2005,80(3):235-242
Fluorescence quenching in solutions of bovine serum albumin has been investigated in the presence of 6-mercaptopurine and ionic surfactants. Spectroscopic analysis of the emission quenching at different temperatures revealed that the quenching mechanism of bovine serum albumin by 6-mercaptopurine was dynamic quenching mechanism. The Stern–Volmer quenching model has been successfully applied, and the activation energy of the interaction between 6-mercaptopurine and bovine serum albumin as much as 4.26 kJ mol−1 was calculated. The distance r between donor (bovine serum albumin) and acceptor (6-mercaptopurine) was obtained according to fluorescence resonance energy transfer (FRET). The result of synchronous fluorescence spectra shows that the conformation of bovine serum albumin has been changed at the present of 6-mercaptopurine. 相似文献
39.
Anna Michnik K. Michalik A. Kluczewska Zofia Drzazga 《Journal of Thermal Analysis and Calorimetry》2006,84(1):113-117
The thermal denaturation process of bovine and human
both fatty acid containing and fatty acid free albumins in aqueous solution
was studied by use of differential scanning calorimetry. Human serum albumins
were found to be more stable than their bovine counterparts. Fatty acid free
albumins were characterized as generally less stable, more susceptible to
aggregation, their unfolding endothermic transition was less cooperative and
with the smaller degree of reversibility. Deconvolution analysis with using
a non-two-state model with two component transitions showed essential differences
in the thermodynamic parameters between all studied albumins, particularly
regarding the high-temperature component transition. 相似文献
40.
H. Brtell G. Rietz S. Sandqvist M. Berg H. Ehrsson 《Journal of separation science》1982,5(11):596-603
A two- dimensional gas chromatograph based on the Deans switching principle is described. The unit comprises two separate ovens, each containing a fused silica capillary column. The columns are joined in a specially designed manifold permitting heart cuts to be performed without significant decrease in efficiency. The switching speed and the retention time stability of the system made it possible to perform heart cuts of only a few seconds' duration. The system has been used under isothermal conditions for the determination of an amino alcohol (KABI 2128) in the low ng/ml range after trifluoroacetylation and with electron capture detection. A much shorter clean-up procedure could be used in combination with the two-dimensional gas chromatograph as compared to a method using a single glass capillary column. 相似文献