Surface and Sructure Investigations of Membrane Electrode Assembly in DMFC Lifetime Testing~*

设计并组装单电池寿命测试系统,测试直接甲醇燃料电池(DMFC)的运行寿命,获得不同运行时间下单电池的极化和功率曲线.测试结束后,分别对运行过的膜电极(MEA)催化剂(铂黑和铂钌黑)和Nafion117(膜作XRD,HRTEM,FTIR及Raman等表征.考察在长期运行条件下电池寿命性能与膜电极中催化剂的颗粒大小、分布、形态、表面物种以及膜的结构之间的关系.寿命测试结果表明,单电池在不同运行阶段其性能变化也不同.运行前200 h,电池性能衰减较显著;运行200~704 h性能较稳定,运行1 002 h后电池性能恶化.波谱实验发现,单电池长期运行后,其膜电极的阴、阳极催化剂颗粒变大.电池寿命性能的衰退伴随膜电极微结构、表面组成、催化剂/膜界面结构的变化以及Nafion 117(膜的老化.The lifetime and performance of a direct methanol fuel cell (DMFC) were investigatedto understand the correlation between thestructure of catalysts /membrane and cell performanceversus time.The cell polarization and performance curves were obtained during the DMFC operation with the time.The catalysts and Nafion~ membrane of the membrane electrode assembly (MEA) from the lifetime test were comprehensively examined by XRD, HRTEM, FTIRand Raman spectroscope techniques.The results revealed that there was significant performance degradation during the first 200 hours operation; while the degradation was slowing down between 200 and 704hours operation.The degradation became worse after 1 002 h operation.The increases of the catalyst particle size from both anode and cathode catalysts wereobserved after the DMFC lifetime test.The changes of microstructure, surface composition, the interfacial structure of the MEA, and the aging of Nafion~ under the DMFC lifetime tests were also observed.作者联系地址：厦门大学化学系,厦门大学化学系,厦门大学化学系,厦门大学化学系,厦门大学化学系 固体表面物理化学国家重点实验室厦门大学材料科学与工程系厦门361005 ,固体表面物理化学国家重点实验室厦门大学材料科学与工程系厦门361005 ,固体表面物理化学国家重点实验室厦门大学材料科学与工程系厦门361005 ,固体表面物理化学国家重点实验室厦门大学材料科学与工程系厦门361005 ,固体表面物理化学国家重点实验室厦门大学材料科学与工程系厦门361005Author's Address: Department of Chemistry*, Department of Materials Science and Engineering, State Key Laboratory for Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005,Chin

The changes of immunoglobulin G N-glycosylation in blood lipids and dyslipidaemia

Background Alternative N-glycosylation has significant structural and functional consequences on immunoglobulin G (IgG) and can affect immune responses, acting as a switch between pro- and anti-inflammatory IgG functionality. Studies have demonstrated that IgG N-glycosylation is associated with ageing, body mass index, type 2 diabetes and hypertension. Methods Herein, we have demonstrated patterns of IgG glycosylation that are associated with blood lipids in a cross-sectional study including 598 Han Chinese aged 20–68 years. The IgG glycome composition was analysed by ultra-performance liquid chromatography. Results Blood lipids were positively correlated with glycan peak GP6, whereas they were negatively correlated with GP18 (P \u3c 0.05/57). The canonical correlation analysis indicated that initial N-glycan structures, including GP4, GP6, GP9-12, GP14, GP17, GP18 and GP23, were significantly correlated with blood lipids, including total cholesterol, total triglycerides (TG) and low-density lipoprotein (r = 0.390, P \u3c 0.001). IgG glycans patterns were able to distinguish patients with dyslipidaemia from the controls, with an area under the curve of 0.692 (95% confidence interval 0.644–0.740). Conclusions Our findings indicated that a possible association between blood lipids and the observed loss of galactose and sialic acid, as well as the addition of bisecting GlcNAcs, which might be related to the chronic inflammation accompanying with the development and procession of dyslipidaemia

Hepatitis C Virus Infection, Linxian, China1

The prevalence of HCV infection was high among older citizens of Linxian, China, in 2000

Heteropolyacid-based materials as heterogeneous photocatalysts

Heteropolyacids (HPAs) that are often used as heteropolyanions are cheap and stable compounds that have been extensively used as acid and oxidation catalysts as a result of their strong Brønsted acidity and ability to undergo multielectron-transfer reactions. HPAs, which are very soluble in water and polar solvents, have been also used as homogeneous photocatalysts for the oxidation of organic substrates in the presence of oxygen, but their use in heterogeneous systems is by far desirable. Dispersing HPAs onto solid supports with high surface area is useful to increase their specific surface area and hence (photo)catalytic activity. Moreover, owing to the high energy gap between the HOMO and LUMO positions of the HPAs, these compounds are activated only by UV light. Consequently, only less than 5 % of the solar light can be used in photocatalytic reactions, which restricts the practical application of HPAs. This microreview is oriented to describe the reported literature on the use of HPA-based materials as heterogeneous photocatalysts for environmental purposes, that is, for the complete or partial oxidation or reduction of organic molecules

An innate defense peptide BPIFA1/SPLUNC1 restricts influenza A virus infection

The airway epithelium secretes proteins that function in innate defense against infection. BPI fold-containing family member A1 (BPIFA1) is secreted into airways and has a protective role during bacterial infections, but it is not known whether it also has an antiviral role. To determine a role in host defense against influenza A virus (IAV) infection and to find the underlying defense mechanism we developed transgenic mouse models that are deficient in BPIFA1 and used these, in combination with in vitro 3D mouse tracheal epithelial cell (mTEC) cultures, to investigate its antiviral properties. We show that BPIFA1 has a significant role in mucosal defense against IAV infection. BPIFA1 secretion was highly modulated after IAV infection. Mice deficient in BPIFA1 lost more weight after infection, supported a higher viral load and virus reached the peripheral lung earlier, indicative of a defect in the control of infection. Further analysis using mTEC cultures showed that BPIFA1-deficient cells bound more virus particles, displayed increased nuclear import of IAV ribonucleoprotein complexes and supported higher levels of viral replication. Our results identify a critical role for BPIFA1 in the initial phase of infection by inhibiting the binding and entry of IAV into airway epithelial cells

Graphene-Based Nanocomposites for Energy Storage

Since the first report of using micromechanical cleavage method to produce graphene sheets in 2004, graphene/graphene-based nanocomposites have attracted wide attention both for fundamental aspects as well as applications in advanced energy storage and conversion systems. In comparison to other materials, graphene-based nanostructured materials have unique 2D structure, high electronic mobility, exceptional electronic and thermal conductivities, excellent optical transmittance, good mechanical strength, and ultrahigh surface area. Therefore, they are considered as attractive materials for hydrogen (H2) storage and high-performance electrochemical energy storage devices, such as supercapacitors, rechargeable lithium (Li)-ion batteries, Li–sulfur batteries, Li–air batteries, sodium (Na)-ion batteries, Na–air batteries, zinc (Zn)–air batteries, and vanadium redox flow batteries (VRFB), etc., as they can improve the efficiency, capacity, gravimetric energy/power densities, and cycle life of these energy storage devices. In this article, recent progress reported on the synthesis and fabrication of graphene nanocomposite materials for applications in these aforementioned various energy storage systems is reviewed. Importantly, the prospects and future challenges in both scalable manufacturing and more energy storage-related applications are discussed

Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30$M_{\odot}$ for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

Potential of Core-Collapse Supernova Neutrino Detection at JUNO

JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve