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关键词： 离合器踏板   异响故障   发动机怠速   诊断   离合器异响   车辆起步   怠速运转   回位弹簧  

摘要： 离合器异响主要表现为：在使用离合器的过程中．即离合器踏板踏下或抬起时发出不正常的响声。可在发动机怠速、车辆起步时进行判断。（1）当发动机怠速运转，放松离合踏板时，离合器发出连续或间断的撞击声。若踏板能用脚勾起，勾起后响声消失，说明踏板回位弹簧过软、脱落或折断，

关键词： 改进遗传算法   层次分析法   离合器   参数优化  

摘要： 针对离合器摩擦片参数优化过程中多目标、多参数、多约束的特点,提出了一种改进遗传算法。采用层次分析法对分目标函数的权重系数进行了初始分配,引入参数间组合度系数和参数的敏感度系数,将组合度系数用于交叉变异中,将敏感度系数用于权重系数动态调整中。以东方红-LA3004拖拉机换挡离合器为优化算例,分别基于传统遗传算法和改进遗传算法对离合器参数进行了优化,将两种优化结果进行了对比分析,结果表明,改进遗传算法能在得到全局最优解的同时,提高优化效率。

关键词： Clutches   Gas   Sliding contact   Frictional heating   FRICTION   WEAR  

摘要： In this contribution the influence of a phase transition from solid organic material to gas on the contact behaviour in dry clutches is investigated. This phase transition may lead to a decrease in transmissible torque commonly known as fading-effect. This process is modelled by describing the clutch friction surface as a porous medium and calculating the flow and inherent pressure field of a gas formed by a thermally induced decomposition of the organic clutch lining. The basic problem is badly conditioned and therefore reduced by asymptotic development of the governing equations. The simulation results show the capability of the proposed model to predict the influence of the phase transition on the fading-effect. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： MELANOMA  

摘要： This Correspondence relates to the article by Dadras et al (A Novel Role for Microphthalmia-Associated Transcription Factor-Regulated Pigment Epithelium-Derived Factor during Melanoma Progression. Am J Pathol 2015, 185:252-265).◆ (Copyright © 2015 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

关键词： Ossification of the posterior longitudinal ligament   Spinal cord   Cervical spine   Finite element analysis   Biomechanics   CEREBROSPINAL-FLUID   EX-VIVO   INJURY   MYELOPATHY   BOVINE   DAMAGE   MODEL  

摘要： Background: There are few studies focusing on the prediction of stress distribution according to the types of ossification of the posterior longitudinal ligament, which can be fundamental information associated with clinical aspects such as the relationship between stress level and neurological symptom severity. In this study, the influence of sagittal and axial types of ossification of the posterior longitudinal ligament on mechanical stress in the cervical spinal cord was investigated. Methods: A three-dimensional finite element model of the cervical spine with spinal cord was developed and validated. The von Mises stresses in the cord and the reduction in cross-sectional areas and volume of the cord were investigated for various axial and sagittal types according to the occupying ratio of ossification of the posterior longitudinal ligament in the spinal canal. Findings: The influence of axial type was less than that of the sagittal type, even though the central type showed higher maximum stresses in the cord, especially for the continuous type. With a 60% occupying ratio of ossification of the posterior longitudinal ligament, the maximum stress was significantly high and the cross-sectional area of the spinal cord was reduced by more than 30% of the intact area regardless of sagittal or axial types. Finally, a higher level of sagittal extension would increase the peak cord tissue stress, which would be related to the neurological dysfunction and tissue damage. Interpretation: Quantitative investigation of biomechanical characteristics such as mechanical stress may provide fundamental information for pre-operative planning of treatment for ossification of the posterior longitudinal ligament. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： Engine Speed   Torque Converter   Wheel Torque   Fuel Consumption Benefit   Pump Actuation  

关键词： GROWTH-FACTOR-BETA   PERITONEAL CARCINOMATOSIS   STROMAL FIBROBLASTS   COLON-CANCER   EXPRESSION   CXCR4   PROLIFERATION   METASTASIS   MODEL  

摘要： Cancer-associated fibroblasts (CAFs) have been considered to play an important role for tumor progression of cancer. Solid tumors contain heterogeneous distribution of oxygen in their microenvironments. This study investigated the growth signaling of gastric cancer (GC) cells in focus on the interaction with CAFs and GC cells under normoxia and hypoxia. Four diffuse-type GC cell lines, two intestinal-type GC cell lines and three CAF cell lines were used. Cells were examined for expression of C-X-C chemokine receptor 4 (CXCR4), fibroblast growth factor receptor 2 (FGFR2) and stromal-derived factor 1 (SDF1) by RT-PCR, western blot, ELISA and immunohistochemical staining of xenografted tumors. GC cell proliferation was examined under hypoxia in the presence or absence of CAFs, a FGFR2 inhibitor, a CXCR4 inhibitor and HIF1a siRNA. Proliferation of diffuse-type GC cells, but not intestinal-type GC cells, was significantly increased by CAFs. CXCR4 expression by diffuse-type GC cells was significantly increased in hypoxia, while FGFR2 expression was decreased. CXCR4 expression was correlated with hypoxic microenvironment of xenografted tumor, but FGFR2 expression was not. FGFR2 inhibition significantly decreased the growth-stimulating activity of CAFs for diffuse-type GC cells in normoxia. In contrast, CXCR4 inhibition significantly decreased the growth-stimulating activity of CAFs in hypoxia. SDF1 production by CAFs was increased in hypoxia, while cancer cells did not produce SDF1. HIF1 siRNA significantly decreased both CXCR4 expression by diffuse-type GC cells and SDF1 production by CAFs. These findings suggest that diffuse-type GC cells might switch their driver pathways from FGFR2 signaling to SDF1/CXCR4 axis through HIF1 in hypoxic tumor microenvironments.

关键词： CXCL10   CXCR3   inducible nitric oxide synthase   leprosy   leprosy type 1 reaction   GENE-EXPRESSION   CHEMOKINE   LESIONS   CELLS   TUBERCULOSIS   GRANULOMAS  

摘要： Background & objectives: Leprosy type 1 reactions (T1R) are acute episodes of immune exacerbation that are a major cause of inflammation and nerve damage. T1R are diagnosed clinically and supported by histopathology. No laboratory marker is currently available that can accurately predict a T1R. Increased plasma and tissue expression of inducible nitric oxide synthase (i-NOS) and chemokine CXCL10 have been demonstrated in T1R. We studied the gene expression and immunoexpression of i-NOS, CXCL10 and its receptor CXCR3 in clinically and histopathologically confirmed patients with T1R and compared with non-reactional leprosy patients to understand which biomarker has better potential in distinguishing reaction from non-reaction. Methods: Gene expression of i-NOS, CXCL10 and CXCR3 was studied in 30 skin biopsies obtained from patients with borderline tuberculoid (BT), mid-borderline (BB) and borderline lepromatous (BL) leprosy with and without T1R by real-time PCR. Further validation was done by immunhistochemical expression on 60 borderline leprosy biopsies with and without T1R. Results: Of the 120 patients histopathological evaluation confirmed T1R in 65 (54.2%) patients. CXCR3 gene expression was significantly (P<0.05) higher in BT- and BB-T1R patients compared to those without T1R. The CXCL10 gene expression was significantly higher (P<0.05) in BB leprosy with T1R but the difference was not significant in patients with BT with or without T1R. Immunoexpression for CXCR3 was significant in both BB-T1R and BB (P<0.001) and BT and BT-T1R (P<0.001). Immunoexpression of CXL10 was significant only in differentiating BB from BB-T1R leprosy (P<0.01) and not the BT cases. i-NOS immunoexpression was not useful in differentiating reactional from non-reactional leprosy. Interpretation & conclusions: Both CXCL10 and CXCR3 appeared to be useful in differentiating T1R reaction in borderline leprosy while CXCR3 alone differentiated BT from BT-T1R. CXCR3 may be a potentially useful im

关键词： Clutch fill control   Pressure control   Automatic transmission   Heavy-duty vehicle   SLIP CONTROLLER   ENGAGEMENT   ROBUST   SYSTEMS   DESIGN  

摘要： In this paper an integrated clutch filling phase control for gearshifts on wet clutch transmissions is developed. In a clutch-to-clutch shift of an automatic transmission, in order to obtain smooth gearshift, it should synchronize the oncoming clutch and the off-going clutch timely as well as precise pressure control for the engagement of the oncoming clutch. However, before the oncoming clutch pressure starts to increase, the initial cavity of the clutch chamber has to be filled first. The filling time and stability of the fill phase are very important for the clutch control. In order to improve the shift quality of the automatic transmission which is equipped on heavy-duty vehicles, the electro-hydraulic clutch actuation system is analysed and modelled. A new fill phase control strategy is proposed based on the system analysis as well as the control parameters are optimized according to the variation of the oil temperature and engine speed. The designed strategy is validated by a simulation work. The results demonstrate that the proposed control strategy and parameters modified method can transit the shift process from the fill phase to the torque phase effectively. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： Porcine circovirus type 2 (PCV2)   Porcine circovirus associated disease (PCVAD)   Porcine reproductive and respiratory syndrome virus (PRRSV)   Co-infection   Programed death ligand-1 (PD-L1)   Programed cell death-1 (PD-1)   Monocyte derived dendritic cells (MoDC)   MULTISYSTEMIC WASTING SYNDROME   PIGS   DISEASE   PCV2   COINFECTION   MODULATION   EXPRESSION   BLOCKADE   B7-H1  

摘要： Porcine circovirus type 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV) continue to have a negative economic impact on global swine production operations. Host immune modulations that potentiate disease during PCV2 and/or PRRSV infections are important areas of ongoing research. In this study, we evaluated the expression levels of PD-L1, CD86, and IL-10 in order to phenotype dendritic cells following viral infection with PCV2b and/or PRRSV. The results showed that the inhibitory marker PD-L1 was significantly increased in monocyte derived dendritic cells (MoDC) in both singular PCV2 infection and PCV2/PRRSV co-infections. MoDC expression of stimulatory marker CD86 was significantly increased during singular PCV2 infections, while it was significantly decreased in the treatment groups co-infected with both PCV2 and PRRSV. IL-10 production was highest among MoDCs that were co-infected with PCV2 and PRRSV. These results indicate that dendritic cells develop a regulatory phenotype following PCV2/PRRSV co-infections. We further investigated the role of the PD-L1/PD-1 axis in lymphocyte anergy, apoptosis, and the induction of regulatory T-cells in porcine mononuclear cell populations. Lymphocyte populations with normal PD-1 expression had higher percentages of anergic, apoptotic lymphocytes and CD4(+)CD25(HIGH)FoxP3(+) regulatory T-cells when compared to a PD-1 deficient lymphocyte population. These results implicate the PD-L1/PD-1 axis in negative regulation of lymphocyte responses in pigs. (C) 2015 Elsevier B.V. All rights reserved.