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41.
Roberto Parra Luis Felipe Verdeja María Florentina Barbés Christian Goñi Vanesa Bazán 《JOM Journal of the Minerals, Metals and Materials Society》2005,57(10):29-36
The Nodal Wear Model was developed to systematize the analysis of corrosion phenomena on refractory and ceramic materials
that come in contact with corrosive fluids in furnace linings. The model is based on the determination of the thermal field
in the furnace lining using a finite-element-method grid in which a second grid is defined to represent the surface of the
lining that is attacked by the molten phases. Using a control equation for the wear-corrosion thermal-activated phenomena,
a modification of the geometry is introduced and a new geometry is defined to restart the calculation.
For more information, contact Roberto A. Parra, Universidad de Concepción-Chile Departamento de Ingeniería Metalúrgica, Edmundo
Larenas 285, Concepcion, Chile; +56-41-20-46-63; fax +56-41-22-00-45; e-mail rparra@udec.cl. 相似文献
42.
43.
Przemysław Gołębiewski Helena Węglarz Magdalena Nakielska Anna Wajler 《International Journal of Applied Ceramic Technology》2021,18(3):697-704
In this work, we investigated the effects of Ca2+ and Mg2+ ions and annealing temperature on the spectroscopic parameters of chromium-doped yttrium aluminum garnet ceramics (Cr:YAG). Samples were obtained with either a separate or a simultaneous addition of calcium and magnesium oxides. To achieve this, aqueous suspensions were prepared using Y2O3, Al2O3, Cr2O3, MgO, and CaO high-purity powders as raw materials. The obtained suspensions were freeze-granulated, pressed into pellets, debinded, and subjected to reactive sintering in vacuum at 1715°C for 6 h. Each material was annealed in air with temperatures between 1300 and 1700°C. Samples were also compared to Cr:YAG ceramics with the addition of silica as a sintering aid. All the materials obtained were then exposed to 445 nm excitation, and emission spectra in the visible and infrared wavelengths were recorded. The results showed that the emission spectra of Cr:YAG ceramics varied according to the annealing conditions: as-sintered samples exhibited strong emissions of around 680 nm and, after air annealing, of around 1400 nm. This phenomenon is attributed to the Cr3+→Cr4+ transition. Samples doped solely with MgO exhibited the highest emission intensity in the infrared region. Thus, Mg2+ ions provided the best conversion efficiency of chromium ions. 相似文献
44.
Cheol Park Won Sup Lee Se-Il Go Sang-Ho Jeong Jiyun Yoo Hee-Jae Cha Young-Joon Lee Heui-Soo Kim Sun-Hee Leem Hye Jung Kim Gon Sup Kim Soon-Chan Hong Yung Hyun Choi 《International journal of molecular sciences》2021,22(6)
Evidence suggests that augmented expression of a certain gene can influence the efficacy of targeted and conventional chemotherapies. Here, we tested whether the high expression of enhancer of the rudimentary homolog (ERH), which serves as a prognostic factor in some cancers, can influence the efficacy of anthocyanins isolated from fruits of Vitis coignetiae Pulliat, Meoru in Korea (AIMs) on human gastric cancer cells. The anticancer efficacy of AIMs was augmented in ERH-transfected MKN28 cells (E-MKN28 cells). Molecularly, ERH augmented AIM-induced caspase-dependent apoptosis by activating caspase-3 and -9. The ERH-augmented apoptotic effect was related to mitochondrial depolarization and inhibition of antiapoptotic proteins, XIAP, and Bcl-2. In addition, reactive oxygen species (ROS) generation was augmented in AIMs-treated E-MKN28 cells compared to AIMs-treated naïve MKN28 cells. In conclusion, ERH augmented AIM-induced caspase-dependent mitochondrial-related apoptosis in MKN28 cells. A decrease in expression of Bcl-2 and subsequent excessive ROS generation would be the mechanism for ERH-augmented mitochondrial-related apoptosis in AIMs-treated MKN28 cells. A decrease in expression of XIAP would be another mechanism for ERH-augmented caspase-dependent apoptosis in AIMs-treated MKN28 cells. 相似文献
45.
Kinoshita Kengo; Sadanami Keishi; Kidera Akinori; Go Nobuhiro 《Protein engineering, design & selection : PEDS》1999,12(1):11-14
In order to search for a common structural motif in the phosphate-bindingsites of proteinmononucleotide complexes, we investigatedthe structural variety of phosphate-binding schemes by an all-against-allcomparison of 491 binding sites found in the Protein Data Bank.We found four frequently occurring structural motifs composedof protein atoms interacting with phosphate groups, each ofwhich appears in different protein superfamilies with differentfolds. The most frequently occurring motif, which we call thestructural P-loop, is shared by 13 superfamilies and is characterizedby a four-residue fragment, GXXX, interacting with a phosphategroup through the backbone atoms. Various sequence motifs, includingWalker's A motif or the P-loop, turn out to be a structuralP-loop found in a few specific superfamilies. The other threemotifs are found in pairs of superfamilies: protein kinase andglutathione synthetase ATPase domain like, actin-like ATPasedomain and nucleotidyltransferase, and FMN-linked oxidoreductaseand PRTase. 相似文献
46.
Seong-Seok Go Hyun-Chul Lee Jae-Yong Lee Ji-Hyun Kim Chul-Woo Chung 《Construction and Building Materials》2009,23(3):1438-1445
Hwangtoh (loess) is a Korean traditional building material that is environment-friendly. It is a natural pozzolanic material with many advantages as a substitute for cement-based materials. It has a high heat-storing capability along with purifying, deodorizing and antibiotic properties. Moreover, the emission of infrared radiation from Hwangtoh is beneficial to the human body. However, because of several practical disadvantages, such as shrinkage cracking and low strength development of concrete incorporating Hwangtoh, the application of Hwangtoh as a mineral admixture has not been quite successful. This study attempts to utilize the advantages of Hwangtoh in the field of modern construction, and suggests potential application of Hwangtoh as a substitute for cement-based material. For this purpose, Hwangtoh is activated in the furnace to investigate the optimal activation conditions and the physical properties of mortar incorporating Hwangtoh are investigated. It is found from the results that Hwangtoh shows changes in phase composition and the least amount of voids when activated in the range of 800–850 °C. The slump flow decreases as fineness and replacement ratio increases. The mortar incorporating Hwangtoh still has problems in flow behavior and drying shrinkage, but, at least, our findings lead us to conclude that the activated Hwangtoh can be used as pozzolanic mineral admixtures. 相似文献
47.
Calcitonin gene-related peptide (CGRP)-containing nerve fibers in bone tissue and their involvement in bone remodeling 总被引:5,自引:0,他引:5
Bone remodeling is a process of bone renewal accomplished by osteoclastic bone resorption and osteoblastic bone formation. These two activities are regulated by systemic hormones and by local cytokines and growth factors. Moreover, the nervous system and certain neuropeptides seem to be involved in regulation of bone remodeling. In this paper, we focus on the distribution of CGRP-containing nerve fibers and their dynamics, and discuss the role of these fibers as a possible mechanism for nervous system involvement in regulation of bone remodeling. CGRP-immunoreactive nerve fibers are widely distributed in bone tissue, such as periosteum and bone marrow, and show apparent regional distribution with different densities. They are often associated with blood vessels and show a beaded appearance. The wide distribution of CGRP-immunoreactive nerve fibers in bone tissue and the changes in distribution during bone development and regeneration suggest the involvement of these fibers in bone remodeling. The effect of CGRP on bone remodeling could partly be through its action on blood vessels, thereby regulating local blood flow. Moreover, in vitro biochemical data and the localization of CGRP-immunoreactive nerve fibers in the vicinity of bone cells suggest that they are directly involved in local regulation of bone remodeling by elevating the concentration of CGRP in the microenvironment around bone cells, especially during bone growth or repair. 相似文献
48.
49.
Martínez-Ohárriz MC Rodríguez-Espinosa C Martín C Goñi MM Tros-Ilarduya MC Sánchez M 《Drug development and industrial pharmacy》2002,28(6):717-725
Coprecipitates of diflunisal and polyvinylpyrrolidone (PVP K15, K30, and K90) and physical mixtures were studied using x-ray diffraction analysis, infrared (IR) spectroscopy, differential scanning calorimetry (DSC), and hot-stage microscopy. X-ray diffraction results revealed an almost amorphous state, even in coprecipitates with a high content of drug, next to 70%, which was independent of the polymer molecular weight. The IR spectra of 70:30 drug-PVP solid dispersions suggest the formation of diflunisal-PVP hydrogen bonds. For 70:30 drug-polymer ratio, the physical mixture showed linear dissolution kinetics of free crystals, but the corresponding coprecipitates exhibit two different dissolution processes. When the 25:75 drug-polymer dispersion is analyzed by hot-stage microscopy, only solid plates of PVP are observed; the absence of drug particles may be due to a molecular dispersion of the drug into the polymer. Moreover, polymorphic changes of diflunisal were detected in the solid dispersions in comparison with the corresponding physical mixtures, which are always formed by polymorph II. At high concentrations of drug (75:25 and 80:20), x-ray diffraction patterns of solid dispersions showed the partial recrystallization of the drug, displaying the main diffraction peaks of polymorph I when ethanol was used as coprecipitation solvent, whereas diflunisal form IV was obtained in chloroform. 相似文献
50.
Katerina Goševa-Popstojanova Ajay Deep Singh Sunil Mazimdar Fengbin Li 《Empirical Software Engineering》2006,11(1):71-117
The growing availability of Internet access has led to significant increase in the use of World Wide Web. If we are to design
dependable Web–based systems that deal effectively with the increasing number of clients and highly variable workload, it
is important to be able to describe the Web workload and errors accurately. In this paper we focus on the detailed empirical
analysis of the session–based workload and reliability based on the data extracted from actual Web logs of eleven Web servers.
First, we introduce and rigourously analyze several intra–session and inter–session metrics that collectively describe Web
workload in terms of user sessions. Then, we analyze Web error characteristics and estimate the request–based and session–based
reliability of Web servers. Finally, we identify the invariants of the Web workload and reliability that apply through all
data sets considered. The results presented in this paper show that session–based workload and reliability are better indicators
of the users perception of the Web quality than the request–based metrics. 相似文献