数码相机面壳注射成型的浇口优化设计

通过运用Moldnow软件对数码相机面壳注射成型进行了流动模拟分析,预测在不同浇口位置和数目的情况下可能存在的气泡和熔接痕位置,确定了最佳的浇口数目和位置.     

2号高炉高冶强下的指标优化措施

在高冶强的生产状态下,高炉如何优化各项技术经济指标,降低其成本,从而提高产品竞争力,是现代高炉操作者积极探索的问题。梅钢2号高炉通过精料、优化操作、改进工艺措施等的实施,实现了高炉高冶强下的指标优化。     

NIR-Triggered Generation of Reactive Oxygen Species and Photodynamic Therapy Based on Mesoporous Silica-Coated LiYF4 Upconverting Nanoparticles

To date, the increase in reactive oxygen species (ROS) production for effectual photodynamic therapy (PDT) treatment still remains challenging. In this study, a facile and effective approach is utilized to coat mesoporous silica (mSiO₂) shell on the ligand-free upconversion nanoparticles (UCNPs) based on the LiYF₄ host material. Two kinds of mesoporous silica-coated UCNPs (UCNP@mSiO₂) that display green emission (doped with Ho³⁺) and red emission (doped with Er³⁺), respectively, were successfully synthesized and well characterized. Three photosensitizers (PSs), merocyanine 540 (MC 540), rose bengal (RB), and chlorin e6 (Ce6), with the function of absorption of green or red emission, were selected and loaded into the mSiO₂ shell of both UCNP@mSiO₂ nanomaterials. A comprehensive study for the three UCNP@mSiO₂/PS donor/acceptor pairs was performed to investigate the efficacy of fluorescence resonance energy transfer (FRET), ROS generation, and in vitro PDT using a MCF-7 cell line. ROS generation detection showed that as compared to the oleate-capped and ligand-free UCNP/PS pairs, the UCNP@mSiO₂/PS nanocarrier system demonstrated more pronounced ROS generation due to the UCNP@mSiO₂ nanoparticles in close vicinity to PS molecules and a higher loading capacity of the photosensitizer. As a result, the three LiYF₄ UCNP@mSiO₂/PS nanoplatforms displayed more prominent therapeutic efficacies in PDT by using in vitro cytotoxicity tests.     

InfluenCe of Downstream Flow on Conduction Phase of Coaxial Plasma Opening Switch

Plasma behaviour and the scaling relations in a coaxial plasma opening switch （POS） using hydrogen plasma are studied self-consistently based on the two-dimensional magnetohydrodynamic （MHD） equations in conjunction with the generalized Ohm＇s law. The vacuum region on the right of POS is included in the model and the influence of downstream flow on the conduction characteristics is discussed. It is found that with the penetration of magnetic field, the pure hydrogen plasma is pushed downstream significantly; and POS still conducts current after the magnetic field arrives at the load edge of POS, which is different from the previous experimental results in a multispecies POS. It is because that the noticeable downstream plasma in the pure hydrogen POS may continue to conduct the current, while in the multispecies POS, the downstream plasma is unimportant so that the conduction phase ends soon after the magnetic field reaches the load edge. The scaling relation obtained from the simulations including the downstream region is consistent with the experimental results.     

静电感应晶闸管的I-V特性物理分析

考虑到寿命不等时的双注入效应、载流子寿命,特别是少子空穴寿命的变化、电导调制效应、双注入空间电荷限制效应等因素,对静电感应晶闸管(Static Induction Thyristor,简称SITH)在正向阻断态的整个I-V特性进行了分段物理分析,给出了理论解释并进行了计算,得出的结论与实验观测结果相吻合.     

Glioblastoma Extracellular Vesicle-Specific Peptides Inhibit EV-Induced Neuronal Cytotoxicity

WHO Grade 4 IDH-wild type astrocytoma (GBM) is the deadliest brain tumor with a poor prognosis. Meningioma (MMA) is a more common “benign” central nervous system tumor but with significant recurrence rates. There is an urgent need for brain tumor biomarkers for early diagnosis and effective treatment options. Extracellular vesicles (EVs) are tiny membrane-enclosed vesicles that play essential functions in cell-to-cell communications among tumor cells. We aimed to identify epitopes of brain tumor EVs by phage peptide libraries. EVs from GBM plasma, MMA plasma, or brain tumor cell lines were used to screen phage-displayed random peptide libraries to identify high-affinity peptides. We purified EVs from three GBM plasma pools (23 patients), one MMA pool (10 patients), and four brain tumor cell lines. We identified a total of 21 high-affinity phage peptides (12 unique) specific to brain tumor EVs. The peptides shared high sequence homologies among those selected by the same EVs. Dose–response ELISA demonstrated that phage peptides were specific to brain tumor EVs compared to controls. Peptide affinity purification identified unique brain tumor EV subpopulations. Significantly, GBM EV peptides inhibit brain tumor EV-induced complement-dependent cytotoxicity (necrosis) in neurons. We conclude that phage display technology could identify specific peptides to isolate and characterize tumor EVs.     

Evidence for Oxidative Pathways in the Pathogenesis of PD: Are Antioxidants Candidate Drugs to Ameliorate Disease Progression?

Parkinson’s disease (PD) is a progressive neurodegenerative disorder that arises due to a complex and variable interplay between elements including age, genetic, and environmental risk factors that manifest as the loss of dopaminergic neurons. Contemporary treatments for PD do not prevent or reverse the extent of neurodegeneration that is characteristic of this disorder and accordingly, there is a strong need to develop new approaches which address the underlying disease process and provide benefit to patients with this debilitating disorder. Mitochondrial dysfunction, oxidative damage, and inflammation have been implicated as pathophysiological mechanisms underlying the selective loss of dopaminergic neurons seen in PD. However, results of studies aiming to inhibit these pathways have shown variable success, and outcomes from large-scale clinical trials are not available or report varying success for the interventions studied. Overall, the available data suggest that further development and testing of novel therapies are required to identify new potential therapies for combating PD. Herein, this review reports on the most recent development of antioxidant and anti-inflammatory approaches that have shown positive benefit in cell and animal models of disease with a focus on supplementation with natural product therapies and selected synthetic drugs.     

The Influence of Glow and Afterglow Cold Plasma Treatment on Biochemistry,Morphology, and Physiology of Wheat Seeds

Cold plasma (CP) technology is a technique used to change chemical and morphological characteristics of the surface of various materials. It is a newly emerging technology in agriculture used for seed treatment with the potential of improving seed germination and yield of crops. Wheat seeds were treated with glow (direct) or afterglow (indirect) low-pressure radio-frequency oxygen plasma. Chemical characteristics of the seed surface were evaluated by XPS and FTIR analysis, changes in the morphology of the seed pericarp were analysed by SEM and AFM, and physiological characteristics of the seedlings were determined by germination tests, growth studies, and the evaluation of α-amylase activity. Changes in seed wettability were also studied, mainly in correlation with functionalization of the seed surface and oxidation of lipid molecules. Only prolonged direct CP treatment resulted in altered morphology of the seed pericarp and increased its roughness. The degree of functionalization is more evident in direct compared to indirect CP treatment. CP treatment slowed the germination of seedlings, decreased the activity of α-amylase in seeds after imbibition, and affected the root system of seedlings.     

汽车空气流量传感技术现状与发展趋势

电喷系统是汽车的核心控制系统,它以空气流量传感器测量获得的进气量为依据确定喷油量与点火时间,从而使得燃料燃烧在理论空燃比附近,以实现更好的安全性、经济性、动力性以及更低的废气排放。因此,进气量的精确测量对汽车电喷系统具有非常重要的意义。介绍了汽车电喷系统空气流量传感技术的现状、存在的问题及发展趋势,并提出了一种采用平行平板电容原理结合涡街原理的传感方式。     

远程线程注入DLL的检测与卸载方法研究

研究了Windows操作系统下的一种木马检测技术,该木马结合了远程线程注入、动态链接库（DLL）等技术。针对目前最新的远程线程注入实现木马隐藏的关键技术,提出了一种进程被远程注入动态链接库的检测方法和相应动态链接库的卸载方法。实验表明,这种方法对已被远程线程注入DLL的进程检测和恢复效果明显。