Cyclic Stretch Induces Inducible Nitric Oxide Synthase and Soluble Guanylate Cyclase in Pulmonary Artery Smooth Muscle Cells

In the pulmonary vasculature, mechanical forces such as cyclic stretch induce changes in vascular signaling, tone and remodeling. Nitric oxide is a potent regulator of soluble guanylate cyclase (sGC), which drives cGMP production, causing vasorelaxation. Pulmonary artery smooth muscle cells (PASMCs) express inducible nitric oxide synthase (iNOS), and while iNOS expression increases during late gestation, little is known about how cyclic stretch impacts this pathway. In this study, PASMC were subjected to cyclic stretch of 20% amplitude and frequency of 1 Hz for 24 h and compared to control cells maintained under static conditions. Cyclic stretch significantly increased cytosolic oxidative stress as compared to static cells (62.9 ± 5.9% vs. 33.3 ± 5.7% maximal oxidation), as measured by the intracellular redox sensor roGFP. Cyclic stretch also increased sGCβ protein expression (2.5 ± 0.9-fold), sGC activity (1.5 ± 0.2-fold) and cGMP levels (1.8 ± 0.2-fold), as well as iNOS mRNA and protein expression (3.0 ± 0.9 and 2.6 ± 0.7-fold, respectively) relative to control cells. An antioxidant, recombinant human superoxide dismutase (rhSOD), significantly decreased stretch-induced cytosolic oxidative stress, but did not block stretch-induced sGC activity. Inhibition of iNOS with 1400 W or an iNOS-specific siRNA inhibited stretch-induced sGC activity by 30% and 68% respectively vs. static controls. In conclusion, cyclic stretch increases sGC expression and activity in an iNOS-dependent manner in PASMC from fetal lambs. The mechanism that produces iNOS and sGC upregulation is not yet known, but we speculate these effects represent an early compensatory mechanism to counteract the effects of stretch-induced oxidative stress. A better understanding of the interplay between these two distinct pathways could provide key insights into future avenues to treat infants with pulmonary hypertension.     

烩面的速冻和冷藏条件的研究

通过研究不同的速冻和冷藏条件对烩面面团加工特性和产品质量的影响 ,确定烩面的速冻和冷藏的最佳工艺参数 ,为烩面的工业化生产提供了理论依据     

连续油管的力学行为研究

连续油管以其不同于常规钻杆和油管的材质、作业工艺与装备,有着不可替代的优势,使其在钻井、采油等应用领域得到了飞速发展,与连续油管作业工艺相关的力学问题的研究也在迅速跟进.连续油管向滚筒上缠绕的过程属于弹塑性的拉弯大变形问题,通过虚功形式的动力学普遍方程,得到将连续油管缠绕于滚筒时需要施加在滚筒上的扭矩和驱动液马达的输出功率,发现作用在滚筒上的扭矩与连续油管所受的轴向拉力之间近似呈线性关系.利用弹塑性理论分析了缠绕在滚筒上的连续油管在卸除拉力和弯矩后的力学行为,证明了连续油管在弹塑性卸载过程中不会发生反向屈曲,而且拉力的作用有助于减小回弹,卸载回弹后连续油管的曲率半径随着拉力的增大而单调下降.因此连续油管缠绕上滚筒后一直要保持弯矩,以避免回弹乱管.     

河床式地面厂房整体稳定计算分析

通过对某河床式地面厂房的整体稳定和地基应力的计算,对厂房建筑物结构设计进行调整,解决了厂房机组段基底拉应力问题,以满足规范要求。     

优化生产工艺提高x800腈纶膨体条缩率

文章在借鉴以往生产经验的基础上,利用统计分析与正交试验相结合的方法,对德国拜耳公司x800丝束生产腈纶膨体条提高缩率的制条工艺进行优化选择,既满足顾客20%缩率的要求,又提高了企业的生产效益.     

Laminar flame speeds and extinction limits of conventional and alternative jet fuels

Experimental results of laminar flame speeds and extinction stretch rates for the conventional (Jet-A) and alternative (S-8) jet fuels are acquired and compared to the results from our earlier studies for neat hydrocarbon surrogate components, including n-decane and n-dodecane. Specifically, atmospheric pressure laminar flame speeds are measured using a counterflow twin-flame configuration for Jet-A/O₂/N₂ and S-8/O₂/N₂ mixtures at preheat temperatures of 400, 450, and 470 K and equivalence ratios ranging from 0.7 to 1.4. The flow field is recorded using digital particle image velocimetry. Linear extrapolation is then applied to determine the unstretched laminar flame speed. Experimental data for the extinction stretch rates of the nitrogen diluted jet fuel/oxidizer mixtures as a function of equivalence ratio are also obtained. In addition, the experimental data of Jet-A are compared to the computed values using a chemical kinetic mechanism for a kerosene surrogate reported in literature. A sensitivity analysis is further performed to identify the key reactions affecting the laminar flame speed and extinction stretch rate for this kerosene surrogate.     

人工神经网络对管材张减精度预测

无缝钢管张力减径是多机架机组对荒管进行无芯棒连轧过程。它具有复杂的金属流动状态，影响其精度的工艺数较多，难以用有轧制理论进行分析。应用人工神经网络的ＢＰ算法，对不同坏料样本进行训练学习，确定其权值和阈值，建立起预测管材精度的数学模型。经试验证明该模型具有较高的可靠性和精度。     

先简支后连续混凝土箱梁施工控制要点

结合先简支后连续混凝土箱梁的特点,对其施工过程中的控制要点进行了介绍,具体阐述了预应力混凝土箱梁预制,预应力张拉及压浆、现浇连续段施工及体系转换等环节的施工工艺及注意事项,以期促进箱梁结构形式的推广应用。     

纬弹包芯竹节纱织物的开发与生产

介绍了经纱为棉等节距竹节纱、纬纱为棉/氨变节距竹节包芯纱斜卡织物的生产工艺,并对生产中采取的关键技术措施进行了探讨,其中细纱和织造是关键工序.     

蒸发器管板模具的结构设计

对蒸发器管板模具结构和设计方法进行改进优化.经过分析和总结前人积累的经验,运用Creo软件及插件来设计制冷设备冷冲落料拉伸模具.通过增加模具结构合理性,采用复合冲压方法,增加打料装置,设计定位装置,满足多型号管板冲压,提高生产效率,减少模具种类及冲压中更换次数.