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排序方式: 共有191条查询结果,搜索用时 234 毫秒
1.
E. A. Van der Burg 《Fresenius' Journal of Analytical Chemistry》1870,9(1):179-203
Ohne Zusammenfassung 相似文献
2.
Eva Eichler Clarence Stanley Rooney Haydn Windsor Richard Williams 《Journal of heterocyclic chemistry》1976,13(4):841-844
The syntheses of some 1,8-naphthyridines substituted in the 6-position with heterocyclic groups are described. A synthetic route to 6-amino-5,7-dimethyl-1,8-naphthyridin-2(1H)one is also presented. 相似文献
3.
Threshold energies Et are determined for photoelectron emission by 20 inorganic anions in aqueous solution (7.1 < Et < 9.1 eV). Calculated values of Et for Cl?, Br?, I? agree with experiment. The Et are correlated with charge-transf absorption spectra. 相似文献
4.
Challenges and strategies in the preparation of large‐volume polymer‐based monolithic chromatography adsorbents
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To date, the number of published reports on the large‐volume preparation of polymer‐based monolithic chromatography adsorbents is still lacking and is of great importance. Many critical factors need to be considered when manufacturing a large‐volume polymer‐based monolith for chromatographic applications. Structural integrity, validity, and repeatability are thought to be the key factors determining the usability of a large‐volume monolith in a separation process. In this review, we focus on problems and solutions pertaining to heat dissipation, pore size distribution, “wall channel” effect, and mechanical strength in monolith preparation. A template‐based method comprising sacrificial and nonsacrificial techniques is possibly the method of choice due to its precise control over the porous structure. However, additional expensive steps are usually required for the template removal. Other strategies in monolith preparation are also discussed. 相似文献
5.
Debbie van der Burg Leila Josefsson Saara Mikkonen Véronique Chotteau Åsa Emmer Hermann Wätzig Cari E. Sänger-van de Griend 《Electrophoresis》2022,43(9-10):922-929
The rapidly growing, competitive biopharmaceutical market requires tight bioprocess monitoring. An integrated, automated platform for the routine online/at-line monitoring of key factors in the cell culture medium could greatly improve process monitoring. Mono- and disaccharides, as the main energy and carbon source, are one of these key factors. A CE-LIF method was developed for the analysis of several mono- and disaccharides, considering requirements and restrictions for analysis in an integrated, automated monitoring platform, such as the possibility for miniaturization to microchip electrophoresis. Analysis was performed after fluorescent derivatization with 8-aminopyrene-1,3,6-trisulfonic acid. The derivatisation reaction and the separation BGE were optimized using design of experiments. The developed method is applicable to the complex matrix of cell culture medium and proved transferable to microchip electrophoresis. 相似文献
6.
Dr. Yuanyuan Li Dr. Shunjie Liu Huwei Ni Haoke Zhang Dr. Hequn Zhang Clarence Chuah Chao Ma Prof. Kam Sing Wong Prof. Jacky W. Y. Lam Prof. Ryan T. K. Kwok Prof. Jun Qian Prof. Xuefeng Lu Prof. Ben Zhong Tang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(31):12922-12926
The traditional design strategies for highly bright solid-state luminescent materials rely on weakening the intermolecular π–π interactions, which may limit diversity when developing new materials. Herein, we propose a strategy of tuning the molecular packing mode by regioisomerization to regulate the solid-state fluorescence. TBP-e-TPA with a molecular rotor in the end position of a planar core adopts a long-range cofacial packing mode, which in the solid state is almost non-emissive. By shifting molecular rotors to the bay position, the resultant TBP-b-TPA possesses a discrete cross packing mode, giving a quantum yield of 15.6±0.2 %. These results demonstrate the relationship between the solid-state fluorescence efficiency and the molecule's packing mode. Thanks to the good photophysical properties, TBP-b-TPA nanoparticles were used for two-photon deep brain imaging. This molecular design philosophy provides a new way of designing highly bright solid-state fluorophores. 相似文献
7.
The transport of fluids in the semicrystalline polymer, poly(aryl ether ether ketone) (PEEK), was investigated. Both solubility and rate of penetration of toluene into PEEK are markedly increased by the application of an external stress. The induction period (i.e., the time for the sorption to begin) is a function of applied stress as well as temperature and crystallinity. At 22°C in 29% crystalline PEEK the induction period was reduced from more than 2000 h to approximately 10 h whereas the solubility of toluene was increased from 9 to 44 wt % upon the application of an external tensile stress of 30 MPa. A critical stress (i.e., a stress value below which the stress-enhanced effects are not observed) was determined. The critical stress is a strong function of crystallinity and temperature. © 1996 John Wiley & Sons, Inc. 相似文献
8.
9.
Gg Edw Thomas Clarence A. Hall und E. Bertarelli 《Fresenius' Journal of Analytical Chemistry》1904,43(10):632-633
Ohne Zusammenfassung 相似文献
10.
F. Xu C.-C. Yang C. Gomillion K. J. L. Burg 《Applied biochemistry and biotechnology》2010,160(1):197-212
Proinflammatory cytokines such as tumor necrosis factor (TNF) α are well known to inhibit adipocyte differentiation. TNF-α
triggers ceramide synthesis through binding of TNF-α to its p55 receptor. Therefore, ceramide is implicated in many of the
multiple signaling pathways initiated by TNF-α. In breast tissue engineering, it is important to know how to modulate adipocyte
differentiation of the stem cells with exogenous additives like ceramide in vitro. We hypothesized that stem cell adipogenesis could be retained in TNF-α-treated preadipocytes in which ceramide synthesis
was blocked and that exogenous ceramide could inhibit adipocyte differentiation. We first studied the effect of ceramide synthase
inhibitor, Fumonisin B2, on the adipogenesis of murine mesenchymal stem cells (D1 cells), treated with TNF-α. We then studied
the effect of specific exogenous C6-ceramide on D1 cell viability and differentiation. It was found that 1 ng/ml of TNF-α
significantly inhibited D1 cell adipogenesis. Cells treated with 5 μM of Fumonisin B2 were able to undergo adipogenesis, even
when treated with TNF-α. High concentrations of exogenous C6-ceramide (>50 μM) had an inhibitory effect, not only on the pre-confluent
proliferation of the D1 cells but also on the post-confluent cell viability. High concentrations of C6-ceramide (>50 μM) also
inhibited mitotic clonal expansion when D1 cell differentiation was induced by the addition of an adipogenic hormonal cocktail.
C6-ceramide at low concentrations (10–25 μM) inhibited lipid production in D1 cells, demonstrated by decreased levels of both
total triglyceride content and specific fatty acid composition percentages. Genetic expression of peroxisome proliferator-activated
receptor (PPAR) γ and aP2 in D1 cells was reduced by C6-ceramide treatment. CCAAT/enhancer-binding protein (C/EBP) β levels
in D1 cells were reduced by C6-ceramide treatment during early differentiation; PPARγ and aP2 protein levels were reduced
at terminal differentiation. C6-ceramide at lower concentrations also decreased lipid accumulation of differentiating D1 cells.
Our results suggest that ceramide synthase inhibitor retains the adipogenic potential of TNF-α-treated mesenchymal stem cells,
while exogenous ceramide at lower concentrations inhibit the adipogenesis of mesenchymal stem cells. Ceramide, therefore,
could be a modulator candidate in breast tissue engineering strategies. 相似文献