Effects of PCSK-9 Inhibition by Alirocumab Treatments on Biliary Cirrhotic Rats

Hyperlipidemia and oxidative stress with elevated oxidized low-density lipoprotein (ox-LDL) exacerbate hepatic inflammation and fibrosis. The plasma level of low-density lipoprotein (LDL) is controlled by proprotein convertase subtilisin/kexin 9 (PCSK9). Alirocumab is a monoclonal antibody that decreases LDL via inhibiting PCSK9 function. Apart from lipid-lowering effects, alirocumab exerts anti-inflammation, anti-angiogenesis and anti-oxidant effects. This study aims to investigate the impact of alirocumab treatment on common bile duct ligation (BDL)-induced biliary cirrhotic rats. After a 4-week treatment of alirocumab, the hemodynamic data, blood biochemistry, ox-LDL level, oxidative stress markers, severity of hepatic encephalopathy and abnormal angiogenesis of BDL rats were measured and compared to the control group. BDL rats presented cirrhotic pictures and elevated ammonia, total cholesterol, LDL and ox-LDL levels compared to the control group. Alirocumab decreased plasma levels of total cholesterol, LDL, and oxidative stress markers; however, it did not affect the hemodynamics, liver and renal biochemistry, and the plasma levels of ammonia and ox-LDL. The motor activities, portal-systemic collaterals and mesenteric vascular density were not significantly different between alirocumab-treated and control groups. In addition, it did not affect hepatic inflammation, intrahepatic angiogenesis, liver fibrosis and free cholesterol accumulation in the liver of BDL rats. In conclusion, PCSK9 inhibition by alirocumab treatment ameliorates hyperlipidemia and systemic oxidative stress in biliary cirrhotic rats. However, it does not affect the plasma level of ox-LDL, intrahepatic inflammation and fibrosis. In addition, PCSK9 inhibition has a neutral effect on abnormal angiogenesis and hepatic encephalopathy in biliary cirrhotic rats.     

基于石墨烯的布洛赫表面波调控特性研究

布洛赫表面波(Bloch surface wave,BSW) 具有传输损耗低、显著表面局域场增强、环境敏感等特性,因而被视为研究近场光和物质相互作用的关键技术。其主要在截断的一维光子晶体与外界介质的界面激发并沿此界面传播,通过传播界面微纳结构的设计,可在纳米尺度实现对BSW的有效调控。本文从BSW的模式特性出发,提出了石墨烯加载的一维光子晶体BSW传感器件结构。通过改变石墨烯层的结构参数,调节激发模式在光子带隙中的位置,研究激发模式的光场传输特性,实现对BSW激发波长、振幅和相位的调控。进一步利用其对外界介质折射率变化非常敏感的特性,对其传感检测能力进行研究。结果表明,该器件有望实现高灵敏度的生化传感检测应用。该研究为新型BSW集成光子器件的设计与发展提供了新思路。     

Relationship between Brain Metabolic Disorders and Cognitive Impairment: LDL Receptor Defect

The low-density-lipoprotein receptor (LDLr) removes low-density lipoprotein (LDL), an endovascular transporter that carries cholesterol from the bloodstream to peripheral tissues. The maintenance of cholesterol content in the brain, which is important to protect brain function, is affected by LDLr. LDLr co-localizes with the insulin receptor and complements the internalization of LDL. In LDLr deficiency, LDL blood levels and insulin resistance increase, leading to abnormal cholesterol control and cognitive deficits in atherosclerosis. Defects in brain cholesterol metabolism lead to neuroinflammation and blood–brain-barrier (BBB) degradation. Moreover, interactions between endoplasmic reticulum stress (ER stress) and mitochondria are induced by ox-LDL accumulation, apolipoprotein E (ApoE) regulates the levels of amyloid beta (Aβ) in the brain, and hypoxia is induced by apoptosis induced by the LDLr defect. This review summarizes the association between neurodegenerative brain disease and typical cognitive deficits.     

边缘氢化石墨烯片层结构和光谱性质的密度泛函理论研究

以并3-6苯环为氢化石墨烯片层模型,采用量子化学密度泛函理论方法(DFT)在B3LYP/6-31G(d,p)水平上进行了几何结构全优化,讨论了分子结构、能量、前线分子轨道等性质的变化规律。在得到化合物基态稳定构型的基础上,运用含时密度泛函理论(TD-DFT)计算了电子吸收光谱的性质。计算结果显示边缘氢化石墨烯片层均为平面结构,线型扶手椅型结构能量最低,结构最稳定。随着石墨烯片层环数的增加HOMO轨道能量增加,LUMO轨道能量降低,能隙能量降低,最大吸收波长明显红移。     

High‐Performance Sodium‐Ion Hybrid Supercapacitor Based on Nb2O5@Carbon Core–Shell Nanoparticles and Reduced Graphene Oxide Nanocomposites

Sodium‐ion hybrid supercapacitors (Na‐HSCs) have potential for mid‐ to large‐scale energy storage applications because of their high energy/power densities, long cycle life, and the low cost of sodium. However, one of the obstacles to developing Na‐HSCs is the imbalance of kinetics from different charge storage mechanisms between the sluggish faradaic anode and the rapid non‐faradaic capacitive cathode. Thus, to develop high‐power Na‐HSC anode materials, this paper presents the facile synthesis of nanocomposites comprising Nb₂O₅@Carbon core–shell nanoparticles (Nb₂O₅@C NPs) and reduced graphene oxide (rGO), and an analysis of their electrochemical performance with respect to various weight ratios of Nb₂O₅@C NPs to rGO (e.g., Nb₂O₅@C, Nb₂O₅@C/rGO‐70, ‐50, and ‐30). In a Na half‐cell configuration, the Nb₂O₅@C/rGO‐50 shows highly reversible capacity of ≈285 mA h g^?1 at 0.025 A g^?1 in the potential range of 0.01–3.0 V (vs Na/Na⁺). In addition, the Na‐HSC using the Nb₂O₅@C/rGO‐50 anode and activated carbon (MSP‐20) cathode delivers high energy/power densities (≈76 W h kg^?1 and ≈20 800 W kg^?1) with a stable cycle life in the potential range of 1.0–4.3 V. The energy and power densities of the Na‐HSC developed in this study are higher than those of similar Li‐ and Na‐HSCs previously reported.     

Functional Free‐Standing Graphene Honeycomb Films

Fabricating free‐standing, three‐dimensional (3D) ordered porous graphene structure can service a wide range of functional materials such as environmentally friendly materials for antibacterial medical applications and efficient solar harvesting devices. A scalable solution processable strategy is developed to create such free‐standing hierarchical porous structures composed of functionalized graphene sheets via an “on water spreading” method. The free‐standing film shows a large area uniform honeycomb structure and can be transferred onto any substrate of interest. The graphene‐based free‐standing honeycomb films exhibit superior broad spectrum antibacterial activity as confirmed using green fluorescent protein labeled Pseudomonas aeruginosa PAO1 and Escherichia coli as model pathogens. Functional nanoparticles such as titanium dioxide (TiO₂) nanoparticles can be easily introduced into conductive graphene‐based scaffolds by premixing. The formed composite honeycomb film electrode shows a fast, stable, and completely reversible photocurrent response accompanying each switch‐on and switch‐off event. The graphene‐based honeycomb scaffold enhances the light‐harvesting efficiency and improves the photoelectric conversion behavior; the photocurrent of the composite film is about two times as high as that of the pure TiO₂ film electrode. Such composite porous films combining remarkably good electrochemical performance of graphene, a large electrode/electrolyte contact area, and excellent stability during the photo‐conversion process hold promise for further applications in water treatment and solar energy conversion.     

石墨烯上生长GaN纳米线

采用金属Ga升华法在石墨烯/蓝宝石衬底上生长了高质量GaN纳米线,研究了不同的生长条件,如NH3流量、反应时间、催化剂和缓冲层等对GaN纳米线形貌的影响,采用扫描电子显微镜(SEM)对GaN纳米线进行表征.研究发现,在适当的NH3流量且无催化剂时,衬底上可以生长出粗细均匀的GaN纳米线.反应时间为5 min时,纳米线密集分布在衬底上,表面光滑.在石墨烯/蓝宝石上预先低温生长GaN缓冲层,然后升温至1 100℃进行GaN纳米线生长,获得了具有择优取向的GaN纳米线结构.研究表明,石墨烯和缓冲层对获得GaN纳米线结构有序阵列具有重要的作用.     

基于多层石墨烯的声表面波放大器的研究

为了研究多层石墨烯对声表面波的放大作用,分析了外加电场下石墨烯载流子的可变电导率,研究了不同衬底下多层石墨烯声表面波放大器的放大性能.对比研究了 ZnO和CdS为衬底的石墨烯声表面波放大器,分别对其在不同载流子漂移速度下的放大倍数进行了研究.结果表明,以ZnO为衬底,载流子漂移速度大于且接近声表面波相速度时,放大性能是...     

Non‐Covalent Functionalization of Graphene Using Self‐Assembly of Alkane‐Amines

A simple, versatile method for non‐covalent functionalization of graphene based on solution‐phase assembly of alkane‐amine layers is presented. Second‐order Møller–Plesset (MP2) perturbation theory on a cluster model (methylamine on pyrene) yields a binding energy of ≈220 meV for the amine–graphene interaction, which is strong enough to enable formation of a stable aminodecane layer at room temperature. Atomistic molecular dynamics simulations on an assembly of 1‐aminodecane molecules indicate that a self‐assembled monolayer can form, with the alkane chains oriented perpendicular to the graphene basal plane. The calculated monolayer height (≈1.7 nm) is in good agreement with atomic force microscopy data acquired for graphene functionalized with 1‐aminodecane, which yield a continuous layer with mean thickness ≈1.7 nm, albeit with some island defects. Raman data also confirm that self‐assembly of alkane‐amines is a non‐covalent process, i.e., it does not perturb the sp² hybridization of the graphene. Passivation and adsorbate n‐doping of graphene field‐effect devices using 1‐aminodecane, as well as high‐density binding of plasmonic metal nanoparticles and seeded atomic layer deposition of inorganic dielectrics using 1,10‐diaminodecane are also reported.     

Gate‐Controlled Energy Barrier at a Graphene/Molecular Semiconductor Junction

The formation of an energy‐barrier at a metal/molecular semiconductor junction is a universal phenomenon which limits the performance of many molecular semiconductor‐based electronic devices, from field‐effect transistors to light‐emitting diodes. In general, a specific metal/molecular semiconductor combination of materials leads to a fixed energy‐barrier. However, in this work, a graphene/C₆₀ vertical field‐effect transistor is presented in which control of the interfacial energy‐barrier is demonstrated, such that the junction switches from a highly rectifying diode at negative gate voltages to a highly conductive nonrectifying behavior at positive gate voltages and at room temperature. From the experimental data, an energy‐barrier modulation of up to 660 meV, a transconductance of up to five orders of magnitude, and a gate‐modulated photocurrent are extracted. The ability to tune the graphene/molecular semiconductor energy‐barrier provides a promising route toward novel, high performance molecular devices.