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101.
102.
Kazuki Nakanishi Yosuke Sato Yayat Ruyat Kazuyuki Hirao 《Journal of Sol-Gel Science and Technology》2003,26(1-3):567-570
Silica gels with hierarchical macropores and mesopores have been prepared by inducing phase separation in the alkoxide-based sol-gel system with an addition of alkyltrimethylammonium salt. Narrowly distributed mesopores were observed in the heat-treated gel samples possibly as a result of supramolecular templating of silica oligomers in the reacting solution. The ionic attractive interaction and hydrophobicity of the attached alkyl group cooperatively determined the phase separation tendency. No indication of long-range order of the mesopores was obtained. 相似文献
103.
Dr. Kenta Arai Takahiko Matsunaga Haruhito Ueno Nozomi Akahoshi Yuumi Sato Dr. Gaurango Chakrabarty Prof. Dr. Govindasamy Mugesh Prof. Dr. Michio Iwaoka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(55):12751-12760
At the redox-active center of thioredoxin reductase (TrxR), a selenenyl sulfide (Se−S) bond is formed between Cys497 and Sec498, which is activated into the thiolselenolate state ([SH,Se−]) by reacting with a nearby dithiol motif ([SHCys59,SHCys64]) present in the other subunit. This process is achieved through two reversible steps: an attack of a cysteinyl thiol of Cys59 at the Se atom of the Se−S bond and a subsequent attack of a remaining thiol at the S atom of the generated mixed Se−S intermediate. However, it is not clear how the kinetically unfavorable second step progresses smoothly in the catalytic cycle. A model study that used synthetic selenenyl sulfides, which mimic the active site structure of human TrxR comprising Cys497, Sec498, and His472, suggested that His472 can play a key role by forming a hydrogen bond with the Se atom of the mixed Se−S intermediate to facilitate the second step. In addition, the selenenyl sulfides exhibited a defensive ability against H2O2-induced oxidative stress in cultured cells, which suggests the possibility for medicinal applications to control the redox balance in cells. 相似文献
104.
The first total synthesis of mycestericin A (1) starting from tartrates is described. The Overman rearrangement of an allylic trichloroacetimidate generated a tetra-substituted carbon with nitrogen, and subsequent stereoselective transformations afforded the highly functionalized vinyl iodide. The cross-coupling of the vinyl iodide with a chiral organozinc species under Negishi conditions, followed by deprotection, completed the total synthesis of 1. 相似文献
105.
A microchip-based cell culture system was developed and a primary culture of rat hepatocytes was realized in the system. The microchip was made of glass plates and had a microchannel and a microculture flask inside. The flask inner surface was coated using collagen solution; then FBS and DMEM were added successively. Rat hepatocytes suspended in a medium was introduced into the microchip and incubated at 37 degrees C in a humidified atmosphere with 5% CO(2). Because of the shortage of dissolved oxygen, the cultured cells in the microchip resulted in a significant decrease in viability. To overcome this, a continuous medium flow oxygen and nutrition supplying system was designed and constructed. The system realized good cell growth for at least 4 days. Liver-specific functions, such as the synthesis of albumin and urea from hepatocytes were confirmed. 相似文献
106.
Microchip-based immunoassay system with branching multichannels for simultaneous determination of interferon-gamma 总被引:1,自引:0,他引:1
A bead-bed immunoassay system suitable for simultaneous assay of multiple samples was constructed on a microchip. The chip had branching multichannels and four reaction and detection regions; the constructed system could process four samples at a time with only one pump unit. Interferon gamma was assayed by a 3-step sandwich immunoassay with the system coupled to a thermal lens microscope as a detector. The biases of the signal intensities obtained from each channel were within 10%, and coefficients of variation were almost the same level as the single straight channel assay. The assay time for four samples was 50 min instead of 35 min for one sample in the single-channel assay; hence higher throughput was realized with the branching structure chip. 相似文献
107.
Taichi Sato Takato Nakamura Toru Takahashi 《Journal of Thermal Analysis and Calorimetry》1985,30(1):97-106
The complexes (R3NHVO(OH)Cl2)2 and (R3RNVO(OH)Cl2)2 prepared by drying in vacuo the organic solutions from the extraction into benzene of aqueous vanadyl chloride solution with trioctylamine (TOA, R3N) and trioctylmethylammonium chloride (TOMAC, R3RNCl), were studied by thermogravimetry and differential thermal analysis under an atmosphere of nitrogen, and the products of their thermal decomposition, such as volatile matter and residues, by gas chromatography. X-ray diffraction and infrared spectroscopy. It was found that the complexes with TOA and TOMAC thermally decompose to V2O3 at 200–300° by cracking of the compounds R3NHVO(OH)Cl2 and R3RNVO(OH)Cl2 formed via dissociation of the complexes at about 150°.
We wish to thank the Koei Chemical Co. Ltd. for samples of TOA and TOMAC. 相似文献
Zusammenfassung Die Komplexe (R3NHVO(OH)Cl2)2 und (R3RNVO(OH)Cl2)2 wurden hergestellt, indem benzolische und wässrige Vanadylchlorid-Lösungen mit Trioctylamin (TOA, R3N) und Trioctylmethylammoniumchlorid (TOMAC, R3RNCl) extrahiert und die erhaltenen Lösungen im Vakuum eingedampft wurden. Die Komplexen wurden in Stickstoffatmosphäre mittels TG und DTA untersucht und die thermischen Zersetzungsprodukte, und zwar sowohl die flüchtigen Verbindungen als auch die Rückstände, gaschromatographisch bzw. röntgendiffraktometrisch und IR-spektroskopisch bestimmt. Es wurde festgestellt, daß die Komplexe mit TOA und TOMAC bei 150° in die Verbindungen R3NHVO(OH)Cl2 und R3RNVO(OH)Cl2 dissoziieren, die bei 200–300° thermisch zu V2O3 zersetzt werden.
(R3NHVO(OH)Cl2)2 (R3RNVO(OH)Cl2)2 (R3,) ( , R3RNCl). , , . , 200–300° V23 R3NV()l2 R3RNVO(OH)Cl2, 150°.
We wish to thank the Koei Chemical Co. Ltd. for samples of TOA and TOMAC. 相似文献
108.
The surface pressure vs. mokcular surface area relations for dipalmitoyl phosphatidylcholine (DPPC) insoluble monolayer and sodium deoxycholate (SDC) adsorbed monolayer,L and D1, respectively, were obtained from the analyses of surface tensions measured by the Wilhelmy glass plate. Also, D1 was obtained by a drop-weight method. Next, the surface pressure time course,(t), of the SDC aq. was measured by the Wilhelmy plate before and after DPPC was spread on the liquid surface. At DPPC spreading,(t) jumped to a maximum,, and decreased along an exponential curve. The values of with various surface amounts of DPPC and bulk concentrations of SDC were analyzed using a dual surface-region model. The model enabled the estimation of. For better fitting, modified relations were constructed in place of D1. The exponential decrease of(t) was also observed on the SDC adsorbed monolayer which was rapidly compressed by a moving barrier. The(t) relaxation rate constants of the SDC monolayers which were compressed by DPPC spreading and the moving barrier agreed with each other, suggesting a desorption of SDC from the surface. 相似文献
109.
Suzumura J Hosoya N Nagao S Mitsui M Nakajima A 《The Journal of chemical physics》2004,121(6):2649-2654
We have studied the electronic structures of several gas phase exohedral lanthanide (Ln)-C(60) clusters, Ln(n)C(60) (Ln=Pr, Ho, Tb, Tm, Eu, and Yb) with n=1-4, by photoionization spectroscopy of the neutrals and photoelectron spectroscopy of their anions. Both of the spectroscopic analyses reveal that most of the Ln atoms preferably take +3 oxidation states, while Eu atoms alone assume +2 oxidation states, and that C(60) accepts up to twelve donated electrons in Ln(n)C(60). An additional photoionization examination of the oxygen atom mixing into the Ln(n)C(60) clusters demonstrated that each oxygen atom reduces two electrons from C(60). This result implies that the number of accepted electrons in C(60) can be varied by a suitable choice of the number of Ln atoms and O atoms. 相似文献
110.
Suzuki Y Yamauchi K Muramatsu K Sato M 《Chemical communications (Cambridge, England)》2004,(23):2770-2771
Chiral N-heterocyclic carbenes, which are derived from C2-symmetric 1,3-bis(1-arylethyl)imidazolium salts, catalyze enantioselective acylation of racemic secondary alcohols. 相似文献