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991.
Jung GY Johnston-Halperin E Wu W Yu Z Wang SY Tong WM Li Z Green JE Sheriff BA Boukai A Bunimovich Y Heath JR Williams RS 《Nano letters》2006,6(3):351-354
High density metal cross bars at 17 nm half-pitch were fabricated by nanoimprint lithography. Utilizing the superlattice nanowire pattern transfer technique, a 300-layer GaAs/AlGaAs superlattice was employed to produce an array of 150 Si nanowires (15 nm wide at 34 nm pitch) as an imprinting mold. A successful reproduction of the Si nanowire pattern was demonstrated. Furthermore, a cross-bar platinum nanowire array with a cell density of approximately 100 Gbit/cm(2) was fabricated by two consecutive imprinting processes. 相似文献
992.
Helden L Eremina E Riefler N Hertlein C Bechinger C Eremin Y Wriedt T 《Applied optics》2006,45(28):7299-7308
We simulate and measure light scattering of a micrometer-sized spherical particle suspended in solution close to a glass substrate. The model, based on the discrete sources method, is developed to describe the experimental situation of total internal reflection microscopy experiments; i.e., the particle is illuminated by an evanescent light field originating from the glass-solvent interface. In contrast to the well-established assumption of a simple exponential decay of the scattering intensity with distance, we demonstrate significant deviations for a certain range of penetration depths and polarization states of the incident light. 相似文献
993.
In the adaptive mesh generation, the space mesh should be adequate to the surface mesh. When the analytical surface representation is not known, additional surface information may be extracted from triangular surface meshes. We describe a new surface reconstruction method which uses approximate Hessian of a piecewise linear function representing the discrete surface. Efficiency of the proposed method is illustrated with two CFD applications. 相似文献
994.
995.
运用新制度主义经济学的制度成本理论,分析了我国国防科研投资体制的现状及存在的主要问题,并从减少国防科研投资的制度成本出发,提出了提高国防科研投资效率的对策性建议. 相似文献
996.
Mikhail G. Gantman Irina G. Tarkhanova Yuri G. Kolyagin 《Journal of Sulfur Chemistry》2016,37(5):501-514
Copper(II) chloride complexes with nitrogen-containing ligands (amines, amides, heterocycles) were studied as catalysts of selective oxidation of thiols to disulfides. This process has an important biochemical analogue – the formation of disulfide bridge in proteins [Wang C, Wesener SR, Zhang H, Cheng Y-Q. An FAD-dependent pyridine nucleotide-disulfide oxidoreductase is involved in disulfide bond formation in FK228 anticancer depsipeptide. Chem and Biol. 2009;16:585–593]; which affects their activity [Zhang L, Chou CP, Moo-Young M. Disulfide bond formation and its impact on the biological activity and stability of recombinant therapeutic proteins produced by Escherichia coli expression system. Biotech Adv. 2011;29:923–929]. Also, thiol oxidation is an important process of oil sweetening. The search for effective and stable catalysts for this reaction is still topical [Ganguly SK, Das G, Kumar S, Sain B, Garg MO. Mechanistic kinetics of catalytic oxidation of 1-butanethiol in light oil sweetening. Catal Tod. 2012;198:246–251]. This article describes a mechanistic study of thiol oxidation and non-innocent ligands transformations during this reaction. The studied ligands are capable of oxidizing thiols, the reaction being followed by reoxidation of the reduced forms of the ligands with air oxygen. The oxidative activity of the ligand correlates with catalyst activity for thiol oxidation. 相似文献
997.
Alexei N. Nekrasov Yuri P. Kozmin Sergey V. Kozyrev Rustam H. Ziganshin Alexandre G. de Brevern Anastasia A. Anashkina 《International journal of molecular sciences》2021,22(15)
Most non-communicable diseases are associated with dysfunction of proteins or protein complexes. The relationship between sequence and structure has been analyzed for a long time, and the analysis of the sequences organization in domains and motifs remains an actual research area. Here, we propose a mathematical method for revealing the hierarchical organization of protein sequences. The method is based on the pentapeptide as a unit of protein sequences. Employing the frequency of occurrence of pentapeptides in sequences of natural proteins and a special mathematical approach, this method revealed a hierarchical structure in the protein sequence. The method was applied to 24,647 non-homologous protein sequences with sizes ranging from 50 to 400 residues from the NRDB90 database. Statistical analysis of the branching points of the graphs revealed 11 characteristic values of y (the width of the inscribed function), showing the relationship of these multiple fragments of the sequences. Several examples illustrate how fragments of the protein spatial structure correspond to the elements of the hierarchical structure of the protein sequence. This methodology provides a promising basis for a mathematically-based classification of the elements of the spatial organization of proteins. Elements of the hierarchical structure of different levels of the hierarchy can be used to solve biotechnological and medical problems. 相似文献
998.
Kunihiro Hasegawa Ryo Takata Hiroki Nishikawa Hirayuki Enomoto Akio Ishii Yoshinori Iwata Yuho Miyamoto Noriko Ishii Yukihisa Yuri Chikage Nakano Takashi Nishimura Kazunori Yoh Nobuhiro Aizawa Yoshiyuki Sakai Naoto Ikeda Tomoyuki Takashima Hiroko Iijima Shuhei Nishiguchi 《International journal of molecular sciences》2016,17(9)
We aimed to examine the effect of Wisteria floribunda agglutinin-positive Mac-2-binding protein (WFA+-M2BP) level on survival comparing with other laboratory liver fibrosis markers in hepatitis C virus (HCV)-related compensated liver cirrhosis (LC) (n = 165). For assessing prognostic performance of continuous fibrosis markers, we adapted time-dependent receiver operating characteristics (ROC) curves for clinical outcome. In time-dependent ROC analysis, annual area under the ROCs (AUROCs) were plotted. We also calculated the total sum of AUROCs in all time-points (TAAT score) in each fibrosis marker. WFA+-M2BP value ranged from 0.66 cutoff index (COI) to 19.95 COI (median value, 5.29 COI). Using ROC analysis for survival, the optimal cutoff point for WFA+-M2BP was 6.15 COI (AUROC = 0.79348, sensitivity = 80.0%, specificity = 74.78%). The cumulative five-year survival rate in patients with WFA+-M2BP ≥ 6.15 COI (n = 69) was 43.99%, while that in patients with WFA+-M2BP < 6.15 COI (n = 96) was 88.40% (p < 0.0001). In the multivariate analysis, absence of hepatocellular carcinoma (p = 0.0008), WFA+-M2BP < 6.15 COI (p = 0.0132), achievement of sustained virological response (p < 0.0001) and des-γ-carboxy prothrombin < 41 mAU/mL (p = 0.0018) were significant favorable predictors linked to survival. In time-dependent ROC analysis in all cases, WFA+-M2BP had the highest TAAT score among liver fibrosis markers. In conclusion, WFA+-M2BP can be a useful predictor in HCV-related compensated LC. 相似文献
999.
Yuri A. Kabachii Sergei Y. Kochev Lyudmila M. Bronstein Inna B. Blagodatskikh Peter M. Valetsky 《Polymer Bulletin》2003,50(4):271-278
Summary
Ti(III) compounds (halides and n-butoxide) along with several mono-, bi-, and tridentate ligands have been studied for the first time in the atom transfer
radical polymerization (ATRP) of styrene. The important advantage of titanium compounds is the white color of the Ti(IV) ions
(Ti in the highest and air stable oxidation state) which ensures the absence of coloring in the final polymer. The better
control over polymerization was realized when conditions increasing the reactivity of the intermediate Ti(IV) species and
decreasing their steady state concentration were maintained. This occurred when chlorides were replaced with bromides (which
decreased the bond strength), and when ligands with low donor ability were employed. Using a sulfide complex of Ti(III) chloride
and 1,2-bis(hexylthio)ethane allowed styrene polymerization with kinetic and molecular weight characteristics inherent to
ATRP.
Received: 2 January 2003 / Accepted: 28 March 2003
Correspondence to Lyudmila M. Bronstein 相似文献
1000.
Liubov A. Tashireva Olga E. Savelieva Evgeniya S. Grigoryeva Yuri V. Nikitin Evgeny V. Denisov Sergey V. Vtorushin Marina V. Zavyalova Nadezhda V. Cherdyntseva Vladimir M. Perelmuter 《International journal of molecular sciences》2021,22(5)
To date, there is indisputable evidence of significant CTC heterogeneity in carcinomas, in particular breast cancer. The heterogeneity of CTCs is manifested in the key characteristics of tumor cells related to metastatic progression – stemness and epithelial–mesenchymal (EMT) plasticity. It is still not clear what markers can characterize the phenomenon of EMT plasticity in the range from epithelial to mesenchymal phenotypes. In this article we examine the manifestations of EMT plasticity in the CTCs in breast cancer. The prospective study included 39 patients with invasive carcinoma of no special type. CTC phenotypes were determined by flow cytometry before any type of treatment. EMT features of CTC were assessed using antibodies against CD45, CD326 (EpCam), CD325 (N-cadherin), CK7, Snail, and Vimentin. Circulating tumor cells in breast cancer are characterized by pronounced heterogeneity of EMT manifestations. The results of the study indicate that the majority of heterogeneous CTC phenotypes (22 out of 24 detectable) exhibit epithelial–mesenchymal plasticity. The variability of EMT manifestations does not prevent intravasation. Co-expression of EpCAM and CK7, regardless of the variant of co-expression of Snail, N-cadherin, and Vimentin, are associated with a low number of CTCs. Intrapersonal heterogeneity is manifested by the detection of several CTC phenotypes in each patient. Interpersonal heterogeneity is manifested by various combinations of CTC phenotypes in patients (from 1 to 17 phenotypes). 相似文献