High‐Performance Alkaline Polymer Electrolyte for Fuel Cell Applications

Although the proton exchange membrane fuel cell (PEMFC) has made great progress in recent decades, its commercialization has been hindered by a number of factors, among which is the total dependence on Pt‐based catalysts. Alkaline polymer electrolyte fuel cells (APEFCs) have been increasingly recognized as a solution to overcome the dependence on noble metal catalysts. In principle, APEFCs combine the advantages of and alkaline fuel cell (AFC) and a PEMFC: there is no need for noble metal catalysts and they are free of carbonate precipitates that would break the waterproofing in the AFC cathode. However, the performance of most alkaline polyelectrolytes can still not fulfill the requirement of fuel cell operations. In the present work, detailed information about the synthesis and physicochemical properties of the quaternary ammonia polysulfone (QAPS), a high‐performance alkaline polymer electrolyte that has been successfully applied in the authors' previous work to demonstrate an APEFC completely free from noble metal catalysts (S. Lu, J. Pan, A. Huang, L. Zhuang, J. Lu, Proc. Natl. Acad. Sci. USA 2008 , 105, 20611), is reported. Monitored by NMR analysis, the synthetic process of QAPS is seen to be simple and efficient. The chemical and thermal stability, as well as the mechanical strength of the synthetic QAPS membrane, are outstanding in comparison to commercial anion‐exchange membranes. The ionic conductivity of QAPS at room temperature is measured to be on the order of 10^?2 S cm^?1. Such good mechanical and conducting performances can be attributed to the superior microstructure of the polyelectrolyte, which features interconnected ionic channels in tens of nanometers diameter, as revealed by HRTEM observations. The electrochemical behavior at the Pt/QAPS interface reveals the strong alkaline nature of this polyelectrolyte, and the preliminary fuel cell test verifies the feasibility of QAPS for fuel cell applications.     

Passive cathodic water/air management device for micro-direct methanol fuel cells

A high efficient passive water/air management device (WAMD) is proposed and successfully demonstrated in this paper. The apparatus consists of cornered micro-channels and air-breathing windows with hydrophobicity arrangement to regulate liquids and gases to flow on their predetermined pathways. A high performance water/air separation with water removal rate of about 5.1 μl s⁻¹ cm⁻² is demonstrated. The performance of the proposed WAMD is sufficient to manage a cathode-generated water flux of 0.26 μl s⁻¹ cm⁻² in the micro-direct methanol fuel cells (μDMFCs) which are operated at 100 mW cm⁻² or 400 mA cm⁻². Furthermore, the condensed vapors can also be collected and recirculated with the existing micro-channels which act as a passive water recycling system for μDMFCs. The durability testing shows that the fuel cells equipped with WAMD exhibit improved stability and higher current density.     

Carbon deposition on Ni/YSZ anodes exposed to CO/H2 feeds

Solid oxide fuel cells (SOFC) can be operated with a variety of fuels. In anode-supported SOFC, these fuels may decompose or react catalytically in the anode compartment resulting in mixtures that, in most cases, include high concentrations of H₂ and CO. In this study, the formation of carbon from CO and H₂ mixtures on Ni/YSZ anodes at 1073 K has been investigated using electrochemical and carbon characterization techniques. More carbon is deposited when Ni/YSZ anodes are exposed to CO/H₂ mixtures than to pure CO. Polarization of the anodes reduced the amount of carbon deposited but the extent of the reduction depended on the gas composition.     

Dye-sensitized solar cell with the hole collector p-CuSCN deposited from a solution in n-propyl sulphide

A method is devised for the deposition of CuSCN on ruthenium bipyridyl dye coated nanocrystalline TiO₂ films from a solution in n-propyl sulphide. The dye-sensitized solid state photovoltaic cell formed was found to yield higher short-circuit photocurrent, open-circuit voltage and efficiency compared to the cells made with CuSCN by other deposition techniques. Factors affecting the stability of the cell are investigated.     

Functionalization of carbon nanotubes by an effective intermittent microwave heating-assisted HF/H2O2 treatment for electrocatalyst support of fuel cells

A method is developed to effectively functionalize carbon nanotubes (CNTs) by intermittent microwave heating (IMH)-assisted HF/H₂O₂ solution treatment. CNTs functionalized by IMH-assisted HF/H₂O₂ solution treatment (CNTs-HF/H₂O₂) are characterized by high oxygen-containing groups and high graphitization degree, as compared with CNTs treated by HF (CNTs-HF) or by IMH-assisted H₂O₂ solution treatment without prior HF treatment (CNTs-H₂O₂). Pt supported on CNTs-HF/H₂O₂ (Pt/CNTs-HF/H₂O₂) has an average particle size of 2.8 nm, smaller than 2.9 nm for Pt supported on CNTs-HF, 3.3 nm for Pt supported on CNTs-H₂O₂ and 4.0 nm for Pt supported on pristine CNTs. Pt/CNTs-HF/H₂O₂ electrocatalysts display a high electrochemical surface area, high Pt utilization efficiency, a superior electrocatalytic and mass activity for the O₂ reduction reaction (ORR) with respect to other catalyst samples in the present study. The results demonstrate the efficiency and effectiveness of the IMH-assisted HF/H₂O₂ solution methods for the functionalization of CNTs, and the method could be easily scaled-up to treat CNTs in large quantities.     

The Effects of Insulin on Immortalized Rat Schwann Cells,IFRS1

Schwann cells play an important role in peripheral nerve function, and their dysfunction has been implicated in the pathogenesis of diabetic neuropathy and other demyelinating diseases. The physiological functions of insulin in Schwann cells remain unclear and therefore define the aim of this study. By using immortalized adult Fischer rat Schwann cells (IFRS1), we investigated the mechanism of the stimulating effects of insulin on the cell proliferation and expression of myelin proteins (myelin protein zero (MPZ) and myelin basic protein (MBP). The application of insulin to IFRS1 cells increased the proliferative activity and induced phosphorylation of Akt and ERK, but not P38-MAPK. The proliferative potential of insulin-stimulated IFRS1 was significantly suppressed by the addition of LY294002, a PI3 kinase inhibitor. The insulin-stimulated increase in MPZ expression was significantly suppressed by the addition of PD98059, a MEK inhibitor. Furthermore, insulin-increased MBP expression was significantly suppressed by the addition of LY294002. These findings suggest that both PI3-K/Akt and ERK/MEK pathways are involved in insulin-induced cell growth and upregulation of MPZ and MBP in IFRS1 Schwann cells.     

Effect of Inducible BMP-7 Expression on the Osteogenic Differentiation of Human Dental Pulp Stem Cells

BMP-7 has shown inductive potential for in vitro osteogenic differentiation of mesenchymal stem cells, which are an ideal resource for regenerative medicine. Externally applied, recombinant BMP-7 was able to induce the osteogenic differentiation of DPSCs but based on our previous results with BMP-2, we aimed to study the effect of the tetracyclin-inducible BMP-7 expression on these cells. DPSC, mock, and DPSC-BMP-7 cell lines were cultured in the presence or absence of doxycycline, then alkaline phosphatase (ALP) activity, mineralization, and mRNA levels of different osteogenic marker genes were measured. In the DPSC-BMP-7 cell line, the level of BMP-7 mRNA significantly increased in the media supplemented with doxycycline, however, the expression of Runx2 and noggin genes was upregulated only after 21 days of incubation in the osteogenic medium with doxycycline. Moreover, while the examination of ALP activity showed reduced activity in the control medium containing doxycycline, the accumulation of minerals remained unchanged in the cultures. We have found that the induced BMP-7 expression failed to induce osteogenic differentiation of DPSCs. We propose three different mechanisms that may worth investigating for the engineering of expression systems that can be used for the induction of differentiation of mesenchymal stem cells.     

Controlled p-doping of pigment layers by cosublimation: Basic mechanisms and implications for their use in organic photovoltaic cells

We present a systematic study on doping of vanadyl- and zinc-pathalocyanine by a fully fluorinated form of tetracyano-quinodimethane as an example of controlled doping of thin organic films by cosublimation of matrix and dopant. The films are characterized in situ by temperature dependent Seebeck and conductivity measurements. We observe a drastic increase of conductivity and a corresponding shift of the Fermi level towards the valence states with increasing dopant concentration. We thus conclude that doping has the potential of both reducing the series resistance and increasing the photovoltage of organic solar cells. As a first step to exploit this potential, we present two different ways of preparing diodes with rectification ratios in excess of 10⁴ using doped phthalocyanines. By adding an undoped interlayer between the contact and the doped layer, we have produced diodes which work already in the strict absence of oxygen and are stable in air. To increase the efficiency of charge carrier generation in photovoltaic cells, we need to use photoactive donor–acceptor-heterojunctions. We present here first examples of pn- and pin-type heterojunctions combining p-doped and nominally undoped layers.     

花椒精油挥发性物质分析及其对红白血病HEL细胞分化和凋亡的影响

目的 研究余庆花椒精油(Yuqing Zanthoxylum bungeanum Essential Oil,YZBO)的挥发性化学物质及其对红白血病HEL细胞分化和凋亡的影响。方法 采用HS-SPME-GC-MS检测分析YZBO的挥发性风味,并以不同质量浓度(1 μg/mL、5 μg/mL和10 μg/mL)YZBO处理HEL细胞24h后,采用MTT和台酚蓝计数分析细胞存活,流式细胞仪检测HEL细胞CD71、CD235a、CD41的分化以及ROS情况,流式细胞仪和Hoechst33258染色法检测HEL细胞凋亡情况。结果 YZBO含有99种化学成分,包括28种醇类物质、7种酯类物质、1种醛类物质、6种酸类物质、4种酮类物质、37种烯烃类、7种烷烃类物质、2种炔烃类物质、2种酚类物质和5种其他物质。橙花叔醇、榄香醇和τ-杜松醇是主要的醇类物质,乙酸苯乙酯和异乔木萜醇乙酸酯是其的主要酯类物质。YZBO对HEL细胞的IC50值为2.94386 μg/mL,促进CD71(45.6%)和CD235a(38.8%)的分化,而对CD41的分化不明显,诱导HEL细胞程序性凋亡,凋亡数目呈剂量和时间依赖性,镜下和染色观察发现细胞体积变小,核固缩以及呈高亮蓝色等典型细胞凋亡形态学改变。结论 YZBO的化合物主要是烷类、醇类和烯类化合物,具有抗红白血病HEL细胞的生物活性,促进分化未成熟的HEL细胞向成熟细胞方向分化,抑制向巨核细胞方向分化,并诱导其凋亡。