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81.
Massimo Venditti Davide Arcaniolo Marco De Sio Sergio Minucci 《International journal of molecular sciences》2021,22(15)
Herein, for the first time, the potential relationships between the cytoskeleton-associated proteins DAAM1 and PREP with different testicular disorders, such as classic seminoma (CS), Leydig cell tumor (LCT), and Sertoli cell-only syndrome (SOS), were evaluated. Six CS, two LCT, and two SOS tissue samples were obtained during inguinal exploration in patients with a suspect testis tumor based on clinical examination and ultrasonography. DAAM1 and PREP protein levels and immunofluorescent localization were analyzed. An increased DAAM1 protein level in CS and SOS as compared to non-pathological (NP) tissue was observed, while LCT showed no significant differences. Conversely, PREP protein level increased in LCT, while it decreased in CS and SOS compared to NP tissue. These results were strongly supported by the immunofluorescence staining, revealing an altered localization and signal intensity of DAAM1 and PREP in the analyzed samples, highlighting a perturbed cytoarchitecture. Interestingly, in LCT spermatogonia, a specific DAAM1 nuclear localization was found, probably due to an enhanced testosterone production, as confirmed by the increased protein levels of steroidogenic enzymes. Finally, although further studies are needed to verify the involvement of other formins and microtubule-associated proteins, this report raised the opportunity to indicate DAAM1 and PREP as new potential markers, supporting the cytoskeleton dynamics changes occurring during normal and/or pathological cell differentiation. 相似文献
82.
V ctor X. Mendoza-Escamilla Alejandro Alonzo-Garc a Helvio R. Mollinedo Israel Gonz lez-Neria J. Antonio Y ez-Varela Sergio A. Martinez-Delgadillo 《中国化学工程学报》2018,26(5):942-956
In turbulence modeling, the RNG and Realizable models have important improvements in the turbulent production and dissipation terms in comparison to the Standard. The selection of the appropriate turbulence model has an impact on the convergence and solution in STRs, and they are used in mixing, multiphase modeling or as starting solution of transient models as DES and LES. Although there are several studies with the pitched blade turbine(PBT) impeller, most of them used the Standard model as representative of all k–ε models, using structured hexahedral grids composed of low number of cells, and in some cases under axial symmetry assumptions.Accordingly, in this work the assessment of the Standard, RNG and Realizable models to describe the turbulent flow field of this impeller, using the Multiple Reference Frame(MRF) and Sliding Mesh(SM) approaches with tetrahedral domains in dense grids, is presented. This kind of cell elements is especially suitable to reproduce complex geometries. Flow velocities and turbulent parameters were verified experimentally by PIV and torque measurements. The three models were capable of predicting fairly the pumping number, the power number based on torque, and velocities. Although the RNG improved the predictions of the turbulent kinetic energy and dissipation rate, the Realizable model presented better performance for both approaches. All models failed in the prediction of the total dissipation rate, and a dependence of its value on the number of cells for the MRF was found. 相似文献
83.
84.
A. Chagnes H. Allouchi B. Carré G. Odou P. Willmann D. Lemordant 《Journal of Applied Electrochemistry》2003,33(7):589-595
-Butyrolactone-ethylene carbonate (BL-EC) mixtures have been investigated as electrolytes for Li-ion batteries using LiPF6 and LiBF4 as lithium salt. The thermal stability of the electrolytes in a large range of temperatures (–90 °C to 40 °C) have been studied by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). From the results of these experiments, the phase diagram of the BL-EC system has been determined. It is characterised by a eutectic point at –56.3 °C and a molar fraction in EC: x
EC = 0.1. A metastable compound has been demonstrated below –90 °C at x
EC = 0.4. Conductivity measurements of BL-EC solutions, in the presence of LiPF6 and LiBF4, indicate that LiPF6 in the eutectic mixture is the most conducting electrolyte in the range of temperatures investigated (–30 °C to room temperature). Nevertheless, at low temperature, LiBF4 based electrolytes compete well with LiPF6, especially when the amount of EC in the mixture is as high as x
EC = 0.5. Moreover, recrystallisation of the salt below –20 °C is avoided when LiBF4 is used as salt. A large increase in viscosity of the solvent mixture is observed when a salt is added, but the increase is lower for LiBF4 than LiPF6. When EC is added to BL at constant salt concentration (1 M), the conductivity of LiPF6 solutions decreases more rapidly than LiBF4 solutions. This has been attributed, at least partially, to the dissociating power of EC. The electrochemical windows of BL-EC (equimolar) mixtures in the presence of LiPF6 and LiBF4 are comparable but it is shown that the solvents oxidation rate at high potentials is lower when LiBF4 is used. 相似文献
85.
86.
Luis J. Salazar-Gastélum Mara Beltrán-Gastélum Julio C. Calva-Yañez Shui Wai Lin Daniel Chávez-Velasco Moisés I. Salazar-Gastélum Sergio Pérez-Sicairos 《应用聚合物科学杂志》2023,140(4):e53359
Anion exchange ionomer (AEI) is a critical component used on anion exchange membrane fuel cell (AEMFC) and alkaline water electrolyzer (AWE). In this work, quaternized polysulfone with different functionalization degree were used as an ionomer to evaluate the performance in the oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR), both implied in the operation of AEMFC and AWE. The synthesized ionomer exhibited a better performance in both reactions in comparison to the commercial AEI Aemion®. PSf-130 exhibited better performance, since IEC and surface area increases twice regarding the same parameters in the PSf-60. The PSf-130 conductivity increases three times regarding the value exhibited by PSf-60. Finally, the Jlim and Jk increases 67% and 100% for ORR. On the other hand, the same catalytic parameter increased 44% and 35% for HOR comparing both polysulfone-based ionomers. The Tafel slope values do not showed drastically changes for different ionomers indicating the same rate determining step (RDS) and the same mechanism in both reactions for all the ionomers. 相似文献
87.
Hengzhong Zhuang Joseph A. Gardella Jr. Joseph A. Incavo Sergio Rojstaczer Jerold C. Rosenfeld 《The Journal of Adhesion》2013,89(1-3):199-214
Angle-dependent electron spectroscopy for chemical analysis (ESCA) was used to examine the air facing surface (20–100 Å thick) composition of polyimidesiloxanes with different processing variations, and of varying polydimethylsiloxane (PDMS) content and block length (number of PDMS repeat unit varies from 1 to 9). Polyimide was clearly detected (due to the nitrogen content) in the 20–100 Å surface regions. This shows that a small amount of PDMS and short PDMS segment lengths in polyimidesiloxanes give a surface region with both PDMS and polyimide present. The surface composition, particularly that in the ca. 100 Å region, was correlated to the peel strength of polyimidesiloxane melt pressed to a metal substrate. Our results suggest that both PDMS and polyimide are essential components to rendering a needed peel strength. PDMS, having a good diffusive ability, readily reaches the substrate upon being pressed, achieving intimate contact, while imide groups interact with the substrate, presumably through chemical bonding; these two factors act synergistically to result in a high peel strength. In addition, the interaction mechanism and the failure mechanism involved in bonding polyimidesiloxane and metal substrate were also elucidated based on the ESCA results. 相似文献
88.
Ana C. S. F. Góes Ozielma Souza Robson T. S. Oliveira Ivana Cesarino Sergio A. S. Machado Katlin I. B. Eguiluz 《Chemical Engineering Communications》2013,200(10):1406-1413
Biodiesel fuel is a renewable energy source normally produced in industry by using an alkaline homogeneous catalyst to promote the transesterification of oil and methanol to fatty acid methyl ester (FAME). Undesirable side reactions occur when poorly refined oils are used, leading to serious problems of product separation and low FAME yield. Therefore, about 85% of the cost of biodiesel is determined by the cost of the feedstock. Here, we describe the development of high-area Pt films deposited on Ti substrates for the electrolytic synthesis of biodiesel from soybean oil containing water, without the addition of catalyst. The higher both the calcination temperature and the number of layers deposited on the Ti surface, the higher the electrochemically active area of Pt exposed to surface. Conversion into esters in electrolysis is proportional to the increase in the superficial area of the Ti/Pt electrodes. Thus, it is possible to synthesize biodiesel using electrodes containing very low amounts of Pt (<0.441 mg cm?2), an important parameter in the industrial production of biodiesel. 相似文献
89.
Sintering of porous alumina obtained by biotemplate fibers for low thermal conductivity applications
Tiago Delbrücke Rogério A. Gouvêa Mário L. Moreira Cristiane W. Raubach José A. Varela Elson Longo Margarete R.F. Gonçalves Sergio Cava 《Journal of the European Ceramic Society》2013,33(6):1087-1092
In this research report, a sintering process of porous ceramic materials based on Al2O3 was employed using a method where a cation precursor solution is embedded in an organic fibrous cotton matrix. For porous green bodies, the precursor solution and cotton were annealed at temperatures in the range of 100–1600 °C using scanning electron microscopy (SEM) and thermogravimetric (TG) analysis to obtain a porous body formation and disposal process containing organic fibers and precursor solution. In a structure consisting of open pores and interconnected nanometric grains, despite the low porosity of around 40% (calculated geometrically), nitrogen physisorption determined a specific surface area of 14 m2/g, which shows much sintering of porous bodies. Energy dispersive X-ray (EDX) and X-ray diffraction (XRD) analytical methods revealed a predominant amount of α-Al2O3 in the sintered samples. Thermal properties of the sintered Al2O3 fibers were obtained by using the Laser Flash which resulted in the lower thermal conductivity obtained by α-Al2O3 and therefore improved its potential use as an insulating material. 相似文献
90.
Silvana M. Demarchi Natalia A. Quintero Ruiz Analía Concellón Sergio A. Giner 《Food and Bioproducts Processing》2013,91(4):310-318
Fruit leathers are pectic gels, eaten as snack or dessert, obtained by dehydrating fruit purees. In this work, apple leathers were prepared by a hot-air drying process which allows the formation of a gel, following the “saccharide–acid–high methoxyl pectin” gelation mechanism. Leathers were produced at 50, 60 and 70 °C, from two formulations: control and added with potassium metabisulphite (KM) as antioxidant. The drying process was studied applying a diffusive model, while antioxidant capacity (AC) losses were represented by a first-order model. Activation energy for drying (20.6 kJ/mol) was lower than those estimated for AC losses in control (31.5 kJ/mol) and KM-added (37.9 kJ/mol) leathers. Therefore, the drying time reduction achieved by increasing air temperature is not sufficient to decrease AC losses in the range covered. AC retention decreased in both formulations at increasing air temperature. KM-added samples showed higher AC retention than the controls, except for those dried at 70 °C. Kinetic constants were lower for KM-added samples, suggesting a protective effect of the additive, especially at moderate air temperatures. In the most favorable situation, AC retention was of only 16%. Therefore, the functional character of these products may not be preserved if dried with hot air and the research on economically viable, less-severe drying technologies should be intensified. 相似文献