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排序方式: 共有1371条查询结果,搜索用时 31 毫秒
161.
A fully integrated polydimethylsiloxane (PDMS)/modified PDMS membrane/SU-8/quartz hybrid chip was developed for protein separation using isoelectric focusing (IEF) mechanism coupled with whole-channel imaging detection (WCID) method. This microfluidic chip integrates three components into one single chip: (i) modified PDMS membranes for separating electrolytes in the reservoirs from the sample in the microchannel and thus reducing pressure disturbance, (ii) SU-8 optical slit to block UV light (below 300?nm) outside the channel aiming to increase detection sensitivity, and (iii) injection and discharge capillaries for continuous operation. Integration of all these components on a single chip is challenging because it requires fabrication techniques for perfect bonding between different materials and is prone to leakage and blockage. This study has addressed all the challenges and presented a fully integrated chip, which is more robust with higher sensitivity than the previously developed IEF chips. This chip was tested by performing protein and pI marker separation. The separation results obtained in this chip were compared with that obtained in commercial cartridges. Side-by-side comparison validated the developed chip and fabrication techniques. 相似文献
162.
Results on the existence and non-existence of nontrivial
\mathbb L1{\mathbb L^1}-solutions of the refinement equation
f(x)=òW|detK(w)|f(K(w)x-L(w))dP(w)f(x)={\int\limits_{\Omega}}|\det K(\omega)|f(K(\omega)x-L(\omega))dP(\omega) 相似文献
163.
Dajana Vuckovic Inés de Lannoy Brad Gien Yingbo Yang Florin Marcel Musteata Robert Shirey Leonard Sidisky Janusz Pawliszyn 《Journal of chromatography. A》2011,1218(21):3367-3375
The use of solid-phase microextraction (SPME) for in vivo sampling of drugs and metabolites in the bloodstream of freely moving animals eliminates the need for blood withdrawal in order to generate pharmacokinetics (PK) profiles in support of pharmaceutical drug discovery studies. In this study, SPME was applied for in vivo sampling in mice for the first time and enables the use of a single animal to construct the entire PK profile. In vivo SPME sampling procedure used commercial prototype single-use in vivo SPME probes with a biocompatible extractive coating and a polyurethane sampling interface designed to facilitate repeated sampling from the same animal. Pre-equilibrium in vivo SPME sampling, kinetic on-fibre standardization calibration and liquid chromatography–tandem mass spectrometry analysis (LC–MS/MS) were used to determine unbound and total circulating concentrations of carbamazepine (CBZ) and its active metabolite carbamazepine-10,11-epoxide (CBZEP) in mice (n = 7) after 2 mg/kg intravenous dosing. The method was linear in the range of 1–2000 ng/mL CBZ in whole blood with acceptable accuracy (93–97%) and precision (<17% RSD). The single dose PK results obtained using in vivo SPME sampling compare well to results obtained by serial automated blood sampling as well as by the more conventional method of terminal blood collection from multiple animals/time point. In vivo SPME offers the advantages of serial and repeated sampling from the same animal, speed, improved sample clean-up, decreased animal use and the ability to obtain both free and total drug concentrations from the same experiment. 相似文献
164.
Agata Górniak Alina Wojakowska Bożena Karolewicz Janusz Pluta 《Journal of Thermal Analysis and Calorimetry》2011,104(3):1195-1200
Enhancement of the dissolution rate of poorly soluble compounds through the formation of drug–drug eutectics was investigated
using fenofibrate and acetylsalicylic acid. Solid–liquid equilibria in the system under study were investigated by differential
scanning calorimetry (DSC). The phase diagram for the whole range of compositions was constructed. In addition, existence
of a metastable polymorph of fenofibrate has been confirmed. The investigation has revealed that acetylsalicylic acid and
fenofibrate form a simple eutectic mixture containing 0.958 mol fraction of fenofibrate at the eutectic point. Dissolution
rate improvement of fenofibrate correlated with the phase diagram. The amount of fenofibrate released from the solid dispersions
that contained fenofibrate as the eutectic mixture with acetylsalicylic acid was at least threefold higher compared to untreated
fenofibrate. 相似文献
165.
166.
Szyperska A Gajewicz A Mazurkiewicz K Leszczynski J Rak J 《Physical chemistry chemical physics : PCCP》2011,13(43):19499-19507
Electron attachment to trimeric complexes that mimic most frequent hydrogen bonding interactions between an amino acid side chain (AASC) and the Watson-Crick (WC) 9-methyladenine-1-methylthymine (MAMT) base pair has been studied at the B3LYP/6-31++G(d,p) level of theory. Although the neutral trimers will not occur in the gas phase due to unfavorable free energy of stabilization (G(stab)) they should form a protein-DNA complex where entropy changes related to formation of such a complex will more than balance its disadvantageous G(stab). The most stable neutrals possess an identical pattern of hydrogen bonds (HBs). In addition, the proton-acceptor (N7) and proton-donor (N10) atoms of adenine involved in those HBs are located in the main groove of DNA. All neutral structures support the adiabatically stable valence anions in which the excess electron is localized on a π* orbital of thymine. The vertical detachment energies (VDEs) of anions corresponding to the most stable neutrals are substantially smaller than that of the isolated WC MAMT base pair. Hence, electron transfer from the anionic thymine to the phosphate group and as a consequence formation of a single strand break (SSB) should proceed more efficiently in a protein-dsDNA complex than in the naked dsDNA as far as electron attachment to thymine is concerned. 相似文献
167.
Aequationes mathematicae - We determine continuous bijections f, acting on a real interval into itself, whose k-fold iterate is the quasi-arithmetic mean of all its subsequent iterates from $$f^0$$... 相似文献
168.
Aequationes mathematicae - 相似文献
169.
Aequationes mathematicae - Assume that $$\Omega \subset \mathbb {R}^k$$ is an open set, V is a real separable Banach space and $$f_1,\ldots ,f_N :\Omega \rightarrow \Omega $$ , $$g_1,\ldots ,... 相似文献
170.
Aequationes mathematicae - Let $$I\subset {\mathbb {R}}$$ be an interval that is closed under addition, and $$ k\in {\mathbb {N}}$$ , $$k\ge 2\,$$ . For a function $$f:I\rightarrow \left( 0,\infty... 相似文献
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