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991.
Aberrant protein glycosylation may be closely associated with cancer pathology. To measure the abundance of protein glycoforms
with a specific glycan structure in plasma samples, we developed a lectin-coupled multiple reaction monitoring (MRM)-based
mass spectrometric method. It was confirmed that the method could provide reproducible results with precision sufficient to
distinguish differences in the abundance of protein glycoforms between individuals. Plasma samples prepared from hepatocellular
carcinoma (HCC) patients without immuno-depletion of highly abundant plasma proteins were fractionated by use of fucose-specific
aleuria aurantia lectin (AAL) immobilized on magnetic beads by use of a biotin–streptavidin conjugate. The lectin-captured
fractions were digested by trypsin and profiled by tandem mass spectrometry. From the proteomic profiling data, target glycoproteins
were selected and analyzed quantitatively by MRM-based analysis. The reproducibility of MRM-based quantification of
the selected target proteins was reliable, with precision (CV; ≤14% for batch-to-batch replicates and ≤19% for replicates
over three days) sufficient to distinguish differences in the abundance of AAL-captured glycoforms between individual plasma
samples. This lectin-coupled, MRM-based method, measuring only lectin-captured glycoforms of a target protein rather than
total target protein, is a tool for monitoring differences between individuals by measuring the abundance of aberrant glycoforms
of a target protein related to a disease. This method may be further applied to rapid verification of biomarker candidates
involved in aberrant protein glycosylation in human plasma. 相似文献
992.
Gangwei Sun Wenhua Song Xiaojun Liu Wenming Qiao Donghui Long Licheng Ling 《Journal of Solid State Electrochemistry》2012,16(3):1263-1270
Mesoporous carbide-derived carbons (CDC) with hierarchical pore structure were fabricated by chlorine etching of mesoporous
titanium carbides. Their capacitive behaviors for electrochemical capacitor were investigated in comparison to those of purely
microporous CDC. The as-prepared mesoporous CDC exhibited not only uniform micropores formed by leaching out titanium atoms
but a 3-D mesoporous network inherited from their parent carbides. These mesoporous CDC could deliver a high specific capacitance
of 120 F g−1 in 1 M tetraethylammonium tetrafluoroborate dissolved in propylene carbonate. Moreover, they owned excellent frequency response
and superior rate capability with capacitance retention ratio of 91% at current density of 10 A g−1. A high energy density of 16.3 Wh kg−1 was obtained even though power density was raised up to 4,300 W kg−1. The distinctive capacitive performance of mesoporous CDC would be attributed to their superior microstructure, in which
the uniform micropores contributed to high charge storage while the 3-D mesoporous network and nanometer-scaled dimension
of particles facilitated ions transfer as well as shortened electrolyte diffusion distance. 相似文献
993.
Xiaodong Zhu Xinbing Chen Yixing Yuan Kening Sun Naiqing Zhang 《Journal of Solid State Electrochemistry》2012,16(1):313-319
SrCo0.8Fe0.2O3-δ (SCF), as a promising cathode material for intermediate temperature solid oxide fuel cells, possesses a high catalytic activity
for the reduction of O2 to 2O2−. The SCF powder was successfully synthesized by the solid state reaction method and Pechini method and characterized using
XRD, particle analysis, and electrochemical performance measurements. Smaller-particle-size SCF materials (SCF-P) with single
phase are obtained at lower synthesis temperature by the Pechini method and possess better electrochemical performance as
compared with those prepared by the solid state reaction method. The reason is that the Pechini method involves the mixing
of elements at atomic level, so pure SCF phase formation can be accelerated and showed high electrocatalytic activity. The
preparation procedure of SCF cathode was firstly investigated using electrochemical impedance spectroscopy. Results show that
the total polarization resistance and the low-frequency resistance decrease gradually with the reduction of the calcination
temperature for the SCF cathodes. The SCF-P cathode sintered at 1,000 °C possesses the highest porosity and the best electrochemical
performance. It is the result of a comprehensive function of three-phase boundary length, porosity of cathode, and the adhesion
between cathode and electrolyte. The charge-transfer process, together with the adsorption, dissociation, and diffusion of
oxygen, has a strong influence on the whole reaction process of the cathode. The influence of binder amounts on the performance
of the SCF-P cathodes was also studied. 相似文献
994.
Keju?Sun Yonghui?Zhao Hai-Yan?Su Wei-Xue?LiEmail author 《Theoretical chemistry accounts》2012,131(2):1118
To identify the transition state accurately and efficiently on a high-dimensional potential energy surface is one of the most
important topics in kinetic studies on chemical reactions. We present here an algorithm to search the transition state by
so-called force reversed method, which only requires a rough reaction direction instead of knowing the initial state and final
state. Compared to the nudged elastic band method and the dimer method that require multiple images, the present algorithm
with only single image required saves significantly the computational cost. The algorithm was implemented in the first-principle
periodic total energy calculation package and applied successfully to several prototype surface processes such as the adsorbate
diffusion and dissociation on metal surfaces. The results indicate that the force reversed method is efficient, robust to
identify the transition state of various surface processes. 相似文献
995.
Either the natural biodegradation process or the industrial hydrolytic process requires synergistic interactions between various
cellulases. However, it is sometimes impeded by low hydrolytic rate of existing cellulases and the lack of accessory enzymes.
Herein, the ability of a commercial cellulase (Spezyme CP, from Genencor) to degrade steam explosion-pretreated corn stover
was significantly improved. Firstly, a fungal cellulase producer, Aspergillus fumigatus ECU0811, was isolated from hundreds of soil samples. A 96-deep-well microscale-based platform was developed here to reduce
the labor-intensive screening work and proved to be consistent with macroscale screening work. After optimization of fermentation,
3% corn cob could induce A. fumigatus ECU0811 to yield the highest cellulase production. Based on the high activities of β-glucosidase and xylanase by A. fumigatus ECU0811, 0.91 and 125 U/mg protein, respectively, an enzyme cocktail was composed with a fixed dosage of Spezyme CP (CPCel)
at 14.2 filter paper units (FPU)/g glucan and varied dosages of A. fumigatus cellulase (AFCel). Consequently, the glucan-to-glucose conversion of corn stover was increased from 25.6% in the presence
of CPCel at a dosage of 14.2 FPU/g glucan to 99.5% in the presence of the enzyme cocktail (14.2 FPU CPCel plus 1.21 FPU AFCel
per gram of glucan). On the other side, it reduced the total protein amount of CPCel by as much as tenfold, which extremely
improved the hydrolytic rate of Spezyme CP and reduced its dosage. 相似文献
996.
The emulsifier-free emulsion copolymerization of α-methylstyrene (AMS) and methyl methacrylate (MMA) in the presence of functional monomer acrylic acid (AA) was carried out in batch process, giving birth to sub-100 nm nanoparticles. The kinetics of polymerization was investigated. The morphology and size of particles were monitored by TEM. The influences of the functional monomer AA concentration, initiator ammonium persulfate (APS) concentration, and polymerization temperature were studied. It was found that AMS caused a drastic decrease in both the rate of polymerization and the average degree of polymerization. The activation energy calculated from Arrhenius plot turned out to be 83.6 kJ/mol. 相似文献
997.
Yin Wang Yuan Fang Guohua Jiang Qi Lv Xinke Sun Miaojun Ding 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(11):890-895
Shell crosslinked nanoparticles, prepared from copolymerization of styrene and disulfide crosslinker, using poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) as stabilizer and macroinitiator, exhibited a special fission behavior during the mini-emulsion RAFT polymerization process. 相似文献
998.
In this work, a series of novel shape memory liquid crystalline (LC) epoxides with lateral substituent were prepared and characterized. Dynamic mechanical analysis (DMA) and shape memory testing were used to investigate on the thermo-mechanical properties and shape memory effects of prepared samples. The results showed that the modulus in the rubbery region (ER ) decreased as the length of lateral alkyl group increases. And more than 95% of the deformation can be fixed as the sample was cooled down below the glass transition temperature (Tg), which was determined by differential scanning calorimetry (DSC) measurement, and can be recovered completely as heating. Effects of the curing agent and substituent on the shape memory behavior were also studied. We found that LC epoxides cured by aromatic diamine have a higher recovery speed. The recovering speeds of the shape memory decreased as the length of lateral alkyl group inscreased. The local ordered structures and the lateral substituent played an important role in shape memory effects. 相似文献
999.
Considering intrinsic properties of conjugated polyfluorenes and special functions of porous polymers, synthesis of fluorinated porous poly(spirobifluorene) via direct C?H arylation polycondensation is explored. Owing to the contorted structure and cross-linking nature, the obtained polymer FPSBF shows permanent porosities with Brunauer–Emmett–Teller specific surface area up to 700 m2 g?1 and exhibits a narrow pore size distribution with the dominant pore size at about 0.63 nm, which is more suitable for adsorption of small gas molecules. Based on the measured gas physisorption isotherms with pressure up to 1.13 bar, the obtained polymer shows good uptaking capacities for hydrogen (1.30 wt% at 1.0 bar and 77 K) and methane (4.80 wt% 1.0 bar and 273 K). Moreover, FPSBF has significant adsorption selectivity for CH4 against N2 and the estimated ideal adsorption selectivity ratio is up to 30/1 at 1.0 bar and 273 K, which makes the material possess potential application in gas separation. 相似文献
1000.
Four symmetrical α,α′,δ,δ′-tetramethyl-cucurbit[6]uril-based compounds have been prepared and characterised by X-ray crystallography. Their crystal structures displayed the acetate anion-selective encapsulating capability of symmetrical α,α′,δ,δ′-tetramethyl-cucurbit[6]uril. The host–guest interaction between the symmetrical α,α′,δ,δ′-tetramethyl-cucurbit[6]uril and the acetate anion in aqueous solution has also been observed by variable temperature 1H NMR spectroscopy. 相似文献