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关键词： Dipeptidyl peptidase 4   Glucagon like peptide 1   Glucose dependent insulinotropic polypeptide   Incretins   Type 2 diabetes   Dyslipidemia   Soluble DPP4  

摘要： Dipeptidyl peptidase 4 (DPP4) is a widely expressed, serine protease which regulates the bioactivity of many peptides through cleavage and inactivation including the incretin hormones, glucagon like peptide - 1 (GLP-1) and glucose dependent insulinotropic polypeptide (GIP). Inhibitors of DPP4 are used therapeutically to treat patients with Type 2 Diabetes Mellitus (T2DM) as they potentiate incretin action to regulate islet hormone secretion and improve glycemia and post-prandial lipid excursions. The widespread clinical use of DPP4 inhibitors has increased interest in the molecular mechanisms by which these drugs mediate their beneficial effects. Traditionally, focus has remained on inhibiting the catalytic activity of DPP4 within the plasma compartment, however evidence is emerging on the importance of inactivation of membrane-bound DPP4 in selective tissue beds to potentiate local hormone gradients. Here we review the recent advances in identifying the cellular sources of both circulating and membrane-bound DPP4 important for cleavage of the incretin hormones and regulation of glucose and lipoprotein metabolism.

关键词： Clutches  

摘要： This work theoretically investigates methods of reducing the energetic cost of bipedal walking while carrying a backpack with a suspension system. We extend a previous 2DOF model proposed by Ackerman and Seipel (2014) by adding a timed clutch to the suspension mechanism. The clutch allows the mechanism to switch between states of elastic or rigid connection of the backpack and the body. Periodic switching between the two states of the mechanism is either event-based or timing-based, and may result in inelastic impacts. We study the hybrid dynamics induced by the action of the clutch mechanism, analyze energy expenditure and stability of periodic solutions, and seek for optimal values of stiffness and switching times that minimize the energetic cost. It is found that in many cases, the clutch mechanism can significantly reduce energy expenditure compared to both rigid and elastic suspensions. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： HEV   DCT   MRAC   control   simulation  

摘要： This paper proposes the use of an adaptive control of a hybrid electric vehicle with dual clutch transmission (HDCT). First, this paper shows mathematical equations for the nonlinear system. Then it presents the linearized model for the proposed system. The control objective of the model reference adaptive controller (MRAC) considered in this paper is to minimize fuel consumption and reduce torque interruption in a hybrid electric vehicle. The MRAC can be used to control the electric motor during changes in speed and gear, and the system can adapt to a model that simulates different driver patterns. The effects of using different model responses as input combinations are analyzed in an effort to exploit the over-actuation feature of the system, as is the sensitivity of the performance to various design factors. The simulation results for an HDCT demonstrate that the MRAC achieves reduced torque interruption and less vehicle jerk compared to the conventional method of operation.

关键词： Allergy   asthma   Staphylococcus aureus   sensitization   serine protease  

摘要： Background: Chronic airway inflammatory diseases, such as chronic rhinosinusitis with nasal polyps and asthma, show increased nasal Staphylococcus aureus colonization. Staphylococcus aureus-derived serine protease-like protein (Spl) D and other closely related proteases secreted by S aureus have recently been identified as inducers of allergic asthma in human subjects and mice, but their mechanism of action is largely unknown. Objective: We investigated the role of recombinant SplD in driving T-H(2)-biased responses and IgE formation in a murine model of allergic asthma. Methods: Allergic asthma was induced in C57BL/6 J wild-type mice, Toll-like receptor (TLR) 4 knockout (Tlr4(-/-)) mice, and recombination-activating gene (Rag2) knockout (Rag2(-/-)) mice by means of repeated intratracheal applications of SplD. Inflammatory parameters in the airways were assessed by means of flow cytometry, ELISA, Luminex, and immunohistochemistry. Serum SplD-specific IgE levels were analyzed by using ELISA. Results: We observed that repeated intratracheal exposure to SplD led to IL-33 and eotaxin production, eosinophilia, bronchial hyperreactivity, and goblet cell hyperplasia in the airways. Blocking IL-33 activity with a soluble ST2 receptor significantly decreased the numbers of eosinophils, IL-13(+) type 2 innate lymphoid cells and IL-13(+) CD4(+) T cells and IL-5 and IL-13 production by lymph node cells but had no effect on IgE production. SplD-induced airway inflammation and IgE production were largely dependent on the presence of the functional adaptive immune system and independent of TLR4 signaling. Conclusion: The S aureus-derived protein SplD is a potent allergen of S aureus and induces a T-H(2)-biased inflammatory response in the airways in an IL-33-dependent but TRL4-independent manner. The soluble ST2 receptor could be an efficient strategy to interfere with SplD-induced T-H(2) inflammation but does not prevent the allergic sensitization.

关键词： adaptive calibration   anti-jerk control   clutch engagement   data-driven fuzzy logic  

摘要： It is well known that the map-based control can reduce the computational burden of the automotive on-board controller. This paper proposes an output-feedback model-reference adaptive control algorithm to calibrate the map-based anti-jerk controller for electromechanical clutch engagement. The algorithm can be used to adaptively construct a data-driven fuzzy rule base without resorting to manual tuning, so that it can overcome the problem of conventional knowledge-based fuzzy logic design, which involves strenuous parameter-tuning work in the construction of calibration maps. To accurately define the consequent of each fuzzy rule for anti-jerk control, an output feedback law for computing the reference trajectory of clutch engagement is developed to eliminate the discontinuous slip-stick transition, whereas an adaptive controller is designed to track the reference trajectory and compensate the nonlinearity. The convergence of the proposed output-feedback model-reference adaptive control algorithm is analyzed. Simulation results indicate that the proposed method can successfully reduce the excessive vehicle jerk and frictional energy dissipation during clutch engagement as compared with the conventional knowledge-based fuzzy logic controller without fine tuning.

关键词： Automated mechanical clutch   Self-learning fuzzy control   Clutch wear   Nonlinear system  

摘要： Automated mechanical clutch is a critical component in vehicle powertrain, whose operations have great influence on fuel economy, comfort, and drivability. However, the control of clutch is a challenging problem due to the nonlinearities and uncertainties, which has attracted extensive attention. This paper proposed a model reference self-learning fuzzy control method with considering clutch wear. Fuzzy control is a simple but effective method to deal with the nonlinear system, but the determined fuzzy rules cannot be suitable for system variations due to clutch wear. Therefore, a self-learning algorithm based on referent model is introduced into fuzzy controller. Then, simulations are carried out in MATLAB/SIMULINK, and the results show that the method solves the problem of clutch wear effectively compared with the fuzzy control without self-learning ability. Finally, a test bench is designed and experiments are carried out to verify the validity of the proposed method.

关键词： Type 1 diabetes   Growth hormone   Insulin like growth factor-I   Portal hypoinsulinization   Height  

摘要： The precise mechanisms relating type 1 diabetes (T1D) and poor glycemic control to the axis of growth hormone (GH), insulin like growth factor-I (IGF-I), and IGF binding protein-3 (IGFBP-3) remain to be definitively determined. GH resistance with low IGF-I as is frequently seen in patients with T1D is often related to portal hypoinsulization, and lack of upregulation of GH receptors. There are conflicting reports of the effect of a dysregulated GH/IGF-I axis on height in children and adolescents with T1D, as well as on chronic complications. This brief review discusses some of the interactions between the GH/IGF-I axis and T1D pathology, and vice versa.

关键词： 变型拖拉机离合器   故障分析   排除  

摘要： 在手动变速拖拉机中,离合器是变速器与发动机之间安装的重要部件,也是拖拉机传动系和发动机之间进行动力传递与切断的重要部件。其好坏会直接关系到拖拉机是否可以平稳的换挡与顺利起步。所以,本文就变型拖拉机离合器常见的故障进行探讨,希望通过问题解决措施的制定,能够满足变型拖拉机使用与维护的实际需求。

关键词： 摩擦离合器   膜片弹簧   载荷变形特性   强化处理  

摘要： 离合器厂家通常采用 A-L 法计算膜片弹簧的载荷变形特性。不过计算载荷同实际生产之间存在较大误差，不能满足设计需求。为解决这一难题，本文研究了膜片弹簧的载荷变形特性计算方法。\n 分析膜片弹簧设计阶段误差产生的原因，针对误差原因开展工作。利用有限元仿真办法，求解膜片弹簧的负荷特性曲线。分析分离指结构对膜片弹簧负荷特性的影响。用转化模型取代不同窗孔形式的膜片弹簧，采用三个转换参数代替不同窗孔的结构参数。分析并得到了三个转换参数对膜片弹簧负荷特性的影响规律。提出并定义了分离指影响系数。利用正交试验设计，获取多组仿真分析数据。采用多元回归分析的方法，拟合得到分离指影响系数同三个转换参数的函数关系表达式。把分离指影响系数作为关于分离指部分的修正项，添加到碟形弹簧精确算法 S-W 法的计算公式上。得出了包含分离指部分影响的膜簧负荷特性计算新方法。实测结果表明，新方法计算峰值误差在 3.5%以内，谷值误差在 9%以内。而 A-L 法计算峰值误差为 10%，谷值误差为 17.5%。分析强化处理对膜簧负荷特性的影响，对新公式进行修正。\n 论文提出了一种更准确的膜片弹簧负荷特性计算方法，有效降低了设计误差。研究成果可用于指导膜片弹簧设计，缩短研发周期，降低设计成本，提高设计效率。

关键词： 锁止离合器   电液控制  

摘要： ZF公司生产的5档自动变速器01V和01L将会逐渐退出市场,并将被新型的6档自动变速器09E所取代.09E变速器型式为电液控制6档行星齿轮机构,装配液力变矩器并带有可调节控制的变矩器锁止离合器.作为维修人员,应熟悉变矩器锁止离合器的电液控制过程,以便于维修变速器时故障的分析与诊断.