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21.
Résumé Les résultats expérimentaux présentés dans cette étude et ceux publiés précédemment montrent que l'électroréduction de l'oxygène se fait dans les sites actifs formés par des ions Mn4+, et que ceux de Mn3+ assurent le transport des électrons au sein du solide.
Certains de ces résultats ont fait l'object d'une communication enPoster à la réunion I.S.E. à Varna, Septembre 1977.
A=Zn, Cr, Al;B = Ni, Cu; et 0 x,y 1. 相似文献
From the results obtained in this study and those presented in previous publications, it can be deduced that the electroreduction of oxygen occurs via electron transfers at active sites created by Mn4+ ions and that Mn3+ ions contribute to the transport of the electrons through the bulk of the electrocatalysts.
Certains de ces résultats ont fait l'object d'une communication enPoster à la réunion I.S.E. à Varna, Septembre 1977.
A=Zn, Cr, Al;B = Ni, Cu; et 0 x,y 1. 相似文献
22.
Nguyen G. D. Ephremides A. Wieselthier J. E. 《Selected Areas in Communications, IEEE Journal on》2006,24(12):2340-2341
For original paper by Zorzi and Rao, see IEEE J. Sel. Areas Commun., vol.12, no.8, p.1289-98 (1994 October) 相似文献
23.
J. Burton A. T. Nguyen Le J. E. Rutledge P. Taborek 《Journal of Low Temperature Physics》2004,134(1-2):275-280
We have studied heterogeneous nucleation of liquid 4He on cesiated surfaces using calorimetric techniques. Nucleation kinetics are strongly influenced by wetting properties. Since liquid 4He does not wet cesium below 2K, substantial supercooling of the vapor is expected on theoretical grounds. Experimentally, however, we have been unable to detect any supercooling in our cells. This may be due to microscopic defects in the Cs coating, which in turn may be related to the fact that we have been unable to find a cell construction material which is wetted by Cs. Somewhat paradoxically, it is possible to supercool helium vapor even in a container made of conventional wetted materials by imposing a large heat and mass flux from the liquid to the vapor across the bulk liquid-vapor interface. When evaporation is sufficiently strong, the vapor above the liquid becomes unstable, and forms a dense fog. Videos of this process show that the fog front propagates rapidly from very near the liquid-vapor interface upward into the vapor. Fog formation near the liquid interface implies that the vapor is in a supercooled metastable state. Qualitative ideas from non-equilibrium thermodynamics and kinetic theory are used to explain this phenomenon. 相似文献
24.
J. Ackermann C. Videlot T.N. Nguyen L. Wang P.M. Sarro F. Fages 《Advanced materials (Deerfield Beach, Fla.)》2004,16(19):1709-1712
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The change in the absorption loss of IR-transmitting chalcogenide glass fibers in the temperature range of -90 degrees C = T = 70 degrees C was investigated. For sulfur-based glass fibers the change in loss relative to room temperature was slightly affected by the temperature in the wavelength region of 1-5 mum. For lambda >/= 6 mum the change in loss was mainly due to multiphonon absorption. The change in loss for tellurium-based glass fibers increased significantly at T = 60 degrees C. The increase in the loss at short wavelengths (lambda = 4.1 mum) was due to electronic excitations in the tail states. Between 5 and 9 mum there was noticeable free-carrier absorption. Beyond lambda >/= 9 mum, multiphonon absorption dominated the loss spectrum. 相似文献
27.
Nam Cong-Nhat Huynh Tze-Ta Huang Chi Thi-Kim Nguyen Fang-Kuei Lin 《International journal of molecular sciences》2022,23(12)
Cancer-associated fibroblasts (CAFs) and partial epithelial–mesenchymal transition (p-EMT) tumor cells are closed together and contribute to the tumor progression of oral squamous cell carcinoma (OSCC). In the present study, we deeply analyzed and integrated OSCC single-cell RNA sequencing datasets to define OSCC CAFs and p-EMT subpopulations. We highlighted the cell–cell interaction network of CAFs and p-EMT tumor cells and suggested biomarkers for the diagnosis and prognosis of OSCC during the metastasis condition. The analysis discovered four subtypes of CAFs: one p-EMT tumor cell population, and cycling tumor cells as well as TNFSF12-TNFRSF25/TNFRSF12A interactions between CAFs and p-EMT tumor cells during tumor metastasis. This suggests the prediction of therapeutically targetable checkpoint receptor–ligand interactions between CAFs and p-EMT tumor cells in OSCC regarding the metastasis status. 相似文献
28.
Hyunjong Byun Jiyeon Park Benedict U. Fabia Joshua Bingwa Mihn Hieu Nguyen Haeshin Lee Jung Hoon Ahn 《International journal of molecular sciences》2022,23(12)
Many heterologous proteins can be secreted by bacterial ATP-binding cassette (ABC) transporters, provided that they are fused with the C-terminal signal sequence, but some proteins are not secretable even though they carry the right signal sequence. The invention of a method to secrete these non-secretable proteins would be valuable both for understanding the secretory physiology of ABC transporters and for industrial applications. Herein, we postulate that cationic “supercharged” regions within the target substrate protein block the secretion by ABC transporters. We also suggest that the secretion of such substrate proteins can be rescued by neutralizing those cationic supercharged regions via structure-preserving point mutageneses. Surface-protruding, non-structural cationic amino acids within the cationic supercharged regions were replaced by anionic or neutral hydrophilic amino acids, reducing the cationic charge density. The examples of rescued secretions we provide include the spike protein of SARS-CoV-2, glutathione-S-transferase, streptavidin, lipase, tyrosinase, cutinase, growth factors, etc. In summary, our study provides a method to predict the secretability and a tool to rescue the secretion by correcting the secretion-blocking regions, making a significant step in understanding the physiological properties of ABC transporter-dependent protein secretion and laying the foundation for the development of a secretion-based protein-producing platform. 相似文献
29.
Saima Usman Hebah Aldehlawi Thuan Khanh Ngoc Nguyen Muy-Teck Teh Ahmad Waseem 《International journal of molecular sciences》2022,23(11)
Vimentin, a type III intermediate filament protein, is found in most cells along with microfilaments and microtubules. It has been shown that the head domain folds back to associate with the rod domain and this association is essential for filament assembly. The N-terminally tagged vimentin has been widely used to label the cytoskeleton in live cell imaging. Although there is previous evidence that EGFP tagged vimentin fails to form filaments but is able to integrate into a pre-existing network, no study has systematically investigated or established a molecular basis for this observation. To determine whether a tag would affect de novo filament assembly, we used vimentin fused at the N-terminus with two different sized tags, AcGFP (239 residues, 27 kDa) and 3 × FLAG (22 residues; 2.4 kDa) to assemble into filaments in two vimentin-deficient epithelial cells, MCF-7 and A431. We showed that regardless of tag size, N-terminally tagged vimentin aggregated into globules with a significant proportion co-aligning with β-catenin at cell–cell junctions. However, the tagged vimentin aggregates could form filaments upon adding untagged vimentin at a ratio of 1:1 or when introduced into cells containing pre-existing filaments. The resultant filament network containing a mixture of tagged and untagged vimentin was less stable compared to that formed by only untagged vimentin. The data suggest that placing a tag at the N-terminus may create steric hinderance in case of a large tag (AcGFP) or electrostatic repulsion in case of highly charged tag (3 × FLAG) perhaps inducing a conformational change, which deleteriously affects the association between head and rod domains. Taken together our results shows that a free N-terminus is essential for filament assembly as N-terminally tagged vimentin is not only incapable of forming filaments, but it also destabilises when integrated into a pre-existing network. 相似文献
30.
Huynh Nguyen Simran Sangha Michelle Pan Dong Ha Shin Hayoung Park Ali I. Mohammed Nicola Cirillo 《International journal of molecular sciences》2022,23(9)
Chemoradiation-induced mucositis is a debilitating condition of the gastrointestinal tract eventuating from antineoplastic treatment. It is believed to occur primarily due to oxidative stress mechanisms, which generate Reactive Oxygen Species (ROS). The aim of this scoping review was to assess the role of oxidative stress in the development of Oral Mucositis (OM). Studies from the literature, published in MEDLINE and SCOPUS, that evaluated the oxidative stress pathways or antioxidant interventions for OM, were retrieved to elucidate the current understanding of their relationship. Studies failing inclusion criteria were excluded, and those suitable underwent data extraction, using a predefined data extraction table. Eighty-nine articles fulfilled criteria, and these were sub-stratified into models of study (in vitro, in vivo, or clinical) for evaluation. Thirty-five clinical studies evaluated antioxidant interventions on OM’s severity, duration, and pain, amongst other attributes. A number of clinical studies sought to elucidate the protective or therapeutic effects of compounds that had been pre-determined to have antioxidant properties, without directly assessing oxidative stress parameters (these were deemed “indirect evidence”). Forty-seven in vivo studies assessed the capacity of various compounds to prevent OM. Findings were mostly consistent, reporting reduced OM severity associated with a reduction in ROS, malondialdehyde (MDA), myeloperoxidase (MPO), but higher glutathione (GSH) and superoxide dismutase (SOD) activity or expression. Twenty-one in vitro studies assessed potential OM therapeutic interventions. The majority demonstrated successful a reduction in ROS, and in select studies, secondary molecules were assessed to identify the mechanism. In summary, this review highlighted numerous oxidative stress pathways involved in OM pathogenesis, which may inform the development of novel therapeutic targets. 相似文献