缸孔珩磨机床工艺特点与珩磨质量问题

通过对一种进口缸孔珩磨机床的研究,详细的介绍了平台网纹珩磨机床常用的工艺设备的特点,以及平台网纹技术在现生产过程中质量问题与解决方法．     

光学头三维悬线式力矩器的高次谐振

研究了分布在聚焦和循迹特性曲线上的高次谐振。对高次谐振的产生机理、物理模型、模态分布和测试方法等进行了研究。根据三维力矩器实际受力状况建立了低转角转动物理模型。利用有限元法分析计算了三维悬线式力矩器的模态分布和振型。介绍了高次谐振的测试方法,并对存在装配误差的力矩器进行实测。测试结果表明:不良力矩器往往在聚焦特性曲线上存在1 700 Hz左右的俯仰共振,在循迹特性曲线上存在4 800 Hz左右的偏转共振,其结果和有限元分析结果一致。结果还表明:高次谐振是光学头三维力矩器的固有属性,抑制高次谐振需要有效减小三维力矩器的装配误差。     

Circulating Ageing Neutrophils as a Marker of Asymptomatic Polyvascular Atherosclerosis in Statin-Naïve Patients without Established Cardiovascular Disease

Background: Current data on the possible involvement of aging neutrophils in atherogenesis are limited. This study aimed to research the diagnostic value of aging neutrophils in their relation to subclinical atherosclerosis in statin-naïve patients without established atherosclerotic cardiovascular diseases (ASCVD). Methods: The study was carried out on 151 statin-naïve patients aged 40–64 years old without ASCVD. All patients underwent duplex scanning of the carotid arteries, lower limb arteries and abdominal aorta. Phenotyping and differentiation of neutrophil subpopulations were performed through flow cytometry (Navios 6/2, Beckman Coulter, USA). Results: The number of CD62L^loCXCR4^hi-neutrophils is known to be significantly higher in patients with subclinical atherosclerosis compared with patients without atherosclerosis (p = 0.006). An increase in the number of CD62L^loCXCR4^hi-neutrophils above cut-off values makes it possible to predict atherosclerosis in at least one vascular bed with sensitivity of 35.4–50.5% and specificity of 80.0–92.1%, in two vascular beds with sensitivity of 44.7–84.4% and specificity of 80.8–33.3%. Conclusion: In statin-naïve patients 40–64 years old without established ASCVD with subclinical atherosclerosis, there is an increase in circulating CD62L^loCXCR4^hi-neutrophils. It was also concluded that the increase in the number of circulating CD62L^loCXCR4^hi-neutrophils demonstrated moderate diagnostic efficiency (AUC 0.617–0.656) in relation to the detection of subclinical atherosclerosis, including polyvascular atherosclerosis.     

Hemp-Derived Nanovesicles Protect Leaky Gut and Liver Injury in Dextran Sodium Sulfate-Induced Colitis

Hemp (Cannabis sativa L.) is used for medicinal purposes owing to its anti-inflammatory and antioxidant activities. We evaluated the protective effect of nanovesicles isolated from hemp plant parts (root, seed, hemp sprout, and leaf) in dextran sulfate sodium (DSS)-induced colitis in mice. The particle sizes of root-derived nanovesicles (RNVs), seed-derived nanovesicles (SNVs), hemp sprout-derived nanovesicles (HSNVs), and leaf-derived nanovesicles (LNVs) were within the range of 100–200 nm as measured by nanoparticle tracking analysis. Acute colitis was induced in C57BL/N mice by 5% DSS in water provided for 7 days. RNVs were administered orally once a day, leading to the recovery of both the small intestine and colon lengths. RNVs, SNVs, and HSNVs restored the tight (ZO-1, claudin-4, occludin) and adherent junctions (E-cadherin and α-tubulin) in DSS-induced small intestine and colon injury. Additionally, RNVs markedly reduced NF-κB activation and oxidative stress proteins in DSS-induced small intestine and colon injury. Tight junction protein expression and epithelial cell permeability were elevated in RNV-, SNV-, and HSNV-treated T84 colon cells exposed to 2% DSS. Interestedly, RNVs, SNVs, HSNVs, and LNVs reduced ALT activity and liver regeneration marker proteins in DSS-induced liver injury. These results showed for the first time that hemp-derived nanovesicles (HNVs) exhibited a protective effect on DSS-induced gut leaky and liver injury through the gut–liver axis by inhibiting oxidative stress marker proteins.     

Pathophysiological Concepts and Management of Pulmonary Manifestation of Pediatric Inflammatory Bowel Disease

Pulmonary manifestation (PM) of inflammatory bowel disease (IBD) in children is a rare condition. The exact pathogenesis is still unclear, but several explanatory concepts were postulated and several case reports in children were published. We performed a systematic Medline search between April 1976 and April 2022. Different pathophysiological concepts were identified, including the shared embryological origin, “miss-homing” of intestinal based neutrophils and T lymphocytes, inflammatory triggering via certain molecules (tripeptide proline-glycine-proline, interleukin 25), genetic factors and alterations in the microbiome. Most pediatric IBD patients with PM are asymptomatic, but can show alterations in pulmonary function tests and breathing tests. In children, the pulmonary parenchyma is more affected than the airways, leading histologically mainly to organizing pneumonia. Medication-associated lung injury has to be considered in pulmonary symptomatic pediatric IBD patients treated with certain agents (i.e., mesalamine, sulfasalazine or infliximab). Furthermore, the risk of pulmonary embolism is generally increased in pediatric IBD patients. The initial treatment of PM is based on corticosteroids, either inhaled for the larger airways or systemic for smaller airways and parenchymal disease. In summary, this review article summarizes the current knowledge about PM in pediatric IBD patients, focusing on pathophysiological and clinical aspects.     

Accumulation of Anthocyanins in Detached Leaves of Kalanchoë blossfeldiana: Relevance to the Effect of Methyl Jasmonate on This Process

Accumulation of anthocyanins in detached leaves and in excised stems of Kalanchoë blossfeldiana kept under natural light conditions in the presence or absence of methyl jasmonate (JA-Me) was investigated. When the abaxial surface of detached leaves was held lower than the adaxial surface (the normal or natural position) under natural light conditions, anthocyanins were not accumulated on the abaxial side of the leaves. In contrast, when the adaxial surface of detached leaves was held lower than the abaxial surface (inverted position), anthocyanins were highly accumulated on the abaxial side of the leaves. These phenomena were independent of the growth stage of K. blossfeldiana as well as photoperiod. Application of JA-Me in lanolin paste significantly inhibited anthocyanin accumulation induced on the abaxial side of detached leaves held in an inverted position in a dose-dependent manner. Anthocyanin accumulation in the excised stem in response to natural light was also significantly inhibited by JA-Me in lanolin paste. Possible mechanisms of anthocyanin accumulation on the abaxial side of detached K. blossfeldiana leaves held in an inverted position under natural light conditions and the inhibitory effect of JA-Me on this process are described. The accompanying changes in the content of primary metabolites and histological analyses were also described.     

Anti-Amnesic Effect of Synbiotic Supplementation Containing Corni fructus and Limosilactobacillus reuteri in DSS-Induced Colitis Mice

This study was conducted to compare the synbiotic activity between Corni fructus (C. fructus) and Limosilactobacillus reuteri (L. reuteri) on dextran sulfate sodium (DSS)-induced colitis and cognitive dysfunction in C57BL/6 mice. C. fructus (as prebiotics, PRE), L. reuteri (as probiotics, PRO), and synbiotics (as a mixture of L. reuteri and C. fructus, SYN) were fed to mice for 3 weeks. Consumption of PRE, PRO, and SYN ameliorated colitis symptoms in body weight, large intestinal length, and serum albumin level. Moreover, SYN showed a synergistic effect on intestinal permeability and intestinal anti-inflammation response. Also, SYN significantly improved cognitive function as a result of measuring the Y-maze and passive avoidance tests in DSS-induced behavioral disorder mice. Especially, SYN also restored memory function by increasing the cholinergic system and reducing tau and amyloid β pathology. In addition, PRE, PRO, and SYN ameliorated dysbiosis by regulating the gut microbiota and the concentration of short-chain fatty acids (SCFAs) in feces. The bioactive compounds of C. fructus were identified with quinic acid, morroniside, loganin, and cornuside, using ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS²). In conclusion, synbiotic supplementation alleviated DSS-induced colitis and cognitive dysfunction by modulating gut microbiota, proinflammatory cytokines, and SCFAs production.     

动态扰动辅助的串行抵消双比特翻转Polar译码算法

针对串行抵消翻转译码算法（Successive Cancellation Flip,SCF）受限于单比特翻转而性能提升有限问题,提出了一种双比特翻转译码算法（Successive Cancellation Flip with 2 Bits,SCF2）。针对SCP算法扰动方差初始值固定的问题,设计了一种扰动方差可随码长和码率变化的改进SCP算法。在此基础上,结合翻转和扰动机制,提出了一种动态扰动辅助的串行抵消双比特翻转（Dynamic Perturbation-Aided SCF2,DPA-SCF2）译码算法,并对其译码复杂度和性能进行了分析。仿真结果显示,相比于列表长度为4的循环冗余校验辅助串行抵消列表（Cyclic Redundancy Check Aided Successive Cancellation List,CA-SCL）译码算法,所提算法最大可获得约0.5 dB的性能增益。     

光轴一致性误差对空间透射式系统像差和质量的影响

红外热成像折转光学系统在复杂环境条件下,光轴容易因为光学元件的偏心或倾斜而发生漂移,影响系统对目标的指示精度。在红外热成像系统设计之初对光学系统开展光轴静态敏感度分析,能够识别出光学系统的敏感点,为满足光轴稳定性的结构优化设计提供约束条件。通过基于旋转矩阵的坐标变换,建立了光学元件旋转过程量和倾斜状态量的转换关系,从而实现了光学元件在任意方向倾斜的空间姿态模拟,确保了光轴敏感度公差分析中的蒙特卡罗采样与结构设计的约束条件相对应,并在此基础上搭建了对红外折转光学系统光轴静态敏感度分析的流程,编制了程序。用所编程序对某典型红外热成像折转光学系统进行实例分析,根据光轴稳定性的指标要求,依次对光学系统中各光学件的偏心量和倾斜量进行了光轴的灵敏度和反灵敏度分析,得出了初始公差限,再针对初始公差限数据进行了任意方向采样的蒙特卡罗分析,最终得出了各光学元件能够满足光轴稳定性指标的偏心和倾斜公差限数据,通过建立多重坐标系的方法验证了所得数据的准确性,为指导光机热优化设计奠定了基础。     

多子波分解技术在储层预测中的应用——以塔里木盆地SN区一间房组为例

塔里木盆地SN区已钻井揭示,在一间房组强波谷之中有良好的油气显示,由于T₇⁴界面的强波峰屏蔽效果,振幅属性的强弱不能有效地预测储层分布,而正演结果则具有多解性。利用多子波分解与重构及第三分量预测了研究区储层分布。利用地震下半周轨迹属性预测的储层边界和发育区与第三分量预测结果基本吻合,与钻井揭示的储层也吻合,强振幅分布区域为有利储层发育带。因此,采用子波分解方法对数据进行处理,去除强轴影响,可得到较好的储层识别效果。