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61.
The spatiotemporal expression of α-tubulin, inversin and dishevelled-1 (DVL-1) proteins associated with the Wnt-signaling pathway, and primary cilia morphology were analyzed in developing kidneys (14th–38th developmental weeks), healthy postnatal (1.5- and 7-years old) and pathologically changed human kidneys, including multicystic dysplastic kidneys (MCDK), focal segmental glomerulosclerosis (FSGS) and nephrotic syndrome of the Finnish type (CNF). The analysis was performed by double immunofluorescence, electron microscopy, semiquantitative and statistical methods. Cytoplasmic co-expression of α-tubulin, inversin and DVL-1 was observed in the proximal convoluted tubules (pct), distal convoluted tubules (dct) and glomeruli (g) of analyzed tissues. During kidney development, the overall expression of α-tubulin, inversin and DVL-1 decreased, while in the postnatal period slightly increased. The highest expressions of α-tubulin and inversin characterized dct and g, while high DVL-1 characterized pct. α-tubulin, inversin and DVL-1 expression pattern in MCDK, FSGS and CNF kidneys significantly differed from the healthy control. Compared to healthy kidneys, pathologically changed kidneys had dysmorphic primary cilia. Different expression dynamics of α-tubulin, inversin and DVL-1 during kidney development could indicate that switch between the canonical and noncanonical Wnt-signaling is essential for normal kidney morphogenesis. In contrast, their disturbed expression in pathological kidneys might be associated with abnormal primary cilia, leading to chronic kidney diseases.  相似文献   
62.
The Cross viscosity model is a generalized non-Newtonian nanofluid model that has widespread engineering and industrial applications like in the synthesis of polymeric solutions, polymeric latex spheres, animal blood, biological fluids, and polyacrylamides. To analyze the micromotion of such nanofluids, a micropolar flow model is introduced. Entropy generation (EG) minimization is important in thermal fluid systems undergoing heat transportation to achieve improved thermohydraulic execution. Homogeneous and heterogeneous reactions involve complex interactions involving the production and consumption of reactant species. Nonlinear thermal radiation plays a vital role in thermal systems undergoing a drastic change in the temperature gradient. The main focus of this study is the investigation of MHD microrotation in Cross nanofluids subject to nonlinear thermal radiation and autocatalytic chemical reactions. The findings from this study show that amplifying the Weissenberg number and power-law index leads to augmentation in axial and transverse fluid velocity components and emaciation in microrotations. Strengthening the magnetic field yields enfeeblement of fluid velocities. In addition, increasing the micropolar parameter leads to the growth of flow velocity, microrotation, and fluid temperature. An increase in Brinkman number contributes to the thicker thermal boundary layer. EG number grows with a rise in Reynolds number.  相似文献   
63.
纳米纤维的制备及性能   总被引:8,自引:0,他引:8  
本文对纳米纤维(Nano-fiber,简写成NF)这种新兴的高技术纤维的发展作了简要介绍。当前,NF包括无机NF和有机NF两类,其发展现状及生产方法各不相同,本文主要对无机NF中的碳NF(CNF)和有机NF中的苯并咪唑NF(PBINF)的生产和发展作了简要介绍。  相似文献   
64.
Both strain and damage sensing properties on carbon nanofiber cement composites (CNFCCs) are reported in the present paper. Strain sensing tests were first made on the material’s elastic range. The applied loading levels have been previously calculated from mechanical strength tests. The effect of several variables on the strain-sensing function was studied, e.g. cement pastes curing age, current density, loading rate or maximum stress applied. All these parameters were discussed using the gage factor as reference. After this first set of elastic experiments, the same specimens were gradually loaded until material’s failure. At the same time both strain and resistivity were measured. The former was controlled using strain gages, and the latter using a multimeter on a four probe setup. The aim of these tests was to prove the sensitivity of these CNF composites to sense their own damage, i.e. check the possibility of fabricating structural damage sensors with CNFCC’s. All samples with different CNF dosages showed good strain-sensing capacities for curing periods of 28 days. Furthermore, a 2% CNF reinforced cement paste has been sensitive to its own structural damage.  相似文献   
65.
高琳  鲁鹏  吴敏  陈顺利  孟志谦 《包装工程》2020,41(15):134-141
目的利用低温等离子体处理PLA膜以提高其亲水性及粘附性,为制备PLA/纳米纤维素复合膜提供一种方法。方法利用单因素试验法探究低温等离子体处理时的放电电压(50~175V)和放电时间(10~50s)对PLA膜表面亲水性和粘附性的影响规律。通过测定PLA膜表面接触角及PLA/纳米纤维素复合膜的剥离强度,分析亲水性及粘附性的变化。利用原子力显微镜观察其微观表面形貌、X射线光电子能谱分析PLA膜表面由疏水性向亲水性转变的机理,并对PLA膜的力学性能及阻隔性能进行分析。结果 PLA膜在低温等离子体条件(放电电压为125V、放电时间为40s、电极距离为4.5cm,氧气流速为1 mL/min,真空度为16.0 kPa)下处理后,其亲水性及与纳米纤维素膜的粘附性达到最佳。此时,PLA膜的接触角由90.0°降至42.4°,PLA/纳米纤维素复合膜的剥离强度为39.5 N/m。结论低温等离子体处理使PLA膜表面由疏水性转变为亲水性,且处理后的PLA可较为牢固地与纳米纤维素膜粘附在一起,从而为PLA/纳米纤维素复合膜的制备提供了一种可行方法。同时,低温等离子体处理对PLA膜的力学性能及阻隔性能没有显著影响。  相似文献   
66.
A new unidirectional carbon fiber prepreg was successfully developed, whose epoxy matrix was physically modified with cellulose nano fibers (CNF). Two different types of prepreg were fabricated using regular carbon fiber (CF) and spread CF tows to identify the effect of prepreg thickness on the mechanical performance including fatigue of quasi isotropic laminates using these prepregs while the thickness of each layer was kept the same (120 μm). The effect of CNF modification of epoxy matrix on the fatigue life is quite significant if thin prepregs were used. It increases greater than 10 times than the fatigue lives of laminates fabricated by regular CF tows/unmodified EP or regular CF tows/modified EP. Uniformly dispersed CNF in the epoxy matrix increases the interfacial strength between CF and matrix.  相似文献   
67.

A fundamental problem in data mining is whether the whole information available is always necessary to represent the information system (IS). Reduct is a rough set approach in data mining that determines the set of important attributes to represent the IS. The search for minimal reduct is based on the assumption that within the dataset in an IS, there are attributes that are more important than the rest. An algorithm in finding minimal reducts based on Propositional Satisfiability (SAT) algorithm is proposed. A branch and bound algorithm is presented to solve the proposed SAT problem. The experimental result shows that the proposed algorithm has significantly reduced the number of rules generated from the obtained reducts with high percentage of classification accuracy.  相似文献   
68.
添加纤维素纳米纤维(CNF)协同阳离子聚丙烯酰胺(CPAM)对沉淀碳酸钙(PCC)进行预絮聚,对不同CNF用量下絮聚体尺寸进行了测定。通过强度因子和再絮聚因子分别对絮聚体强度性能和再絮聚性能进行表征,结果表明当CNF添加量为5%左右时,絮聚体的强度性能和再絮聚性能较佳。对CNF絮聚PCC的机理进行了分析,CNF大的比表面积和高长径比增强了PCC与CPAM的桥连絮聚,使得絮聚体更为密实,强度提升。  相似文献   
69.
A review of vapor grown carbon nanofiber/polymer conductive composites   总被引:3,自引:0,他引:3  
Vapor grown carbon nanofiber (VGCNF)/polymer conductive composites are elegant materials that exhibit superior electrical, electromagnetic interference (EMI) shielding effectiveness (SE) and thermal properties compared to conventional conductive polymer composites. This article reviews recent developments in VGCNF/polymer conductive composites. The article starts with a concise and general background about VGCNF production, applications, structure, dimension, and electrical, thermal and mechanical properties. Next composites of VGCNF/polymer are discussed. Composite electrical, EMI SE and thermal properties are elaborated in terms of nanofibers dispersion, distribution and aspect ratio. Special emphasis is paid to dispersion of nanofibers by melt mixing. Influence of other processing methods such as in-situ polymerization, spinning, and solution processing on final properties of VGCNF/polymer composite is also reviewed. We present properties of CNTs and CFs, which are competitive fillers to VGCNFs, and the most significant properties of their composites compared to those of VGCNF/polymer composites. At the conclusion of the article, we summarize the most significant achievements and address the future challenges and tasks in the area related to characterizing VGCNF aspect ratio and dispersion, determining the influence of processing methods and conditions on VGCNF/polymer composites and understanding the structure/property relationship in VGCNF/polymer composites.  相似文献   
70.
本文综述了近年来纤维素纳米纤丝(CNF)及其相关的复合材料用作生物质基3D打印材料在医学、纺织品、食品、导电材料、智能材料等几个热门领域中的应用研究进展,以及CNF在生物质基3D打印材料中的作用与功能.最后,对CNF作为一种多功能的纳米材料在生物质基3D打印技术中的应用前景做了展望.  相似文献   
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