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cHARAcTERIZATION OF THE SOLUBILIZATION OF LIPID BILAYERS BY SURFAcTANTS

BIOcHIMIcA ET BIOPHYSIcA AcTA 1985年第3期821卷 470-478页

作者： LIcHTENBERG, D Department of Physiology and Pharmacology Tel-Aviv University School of Medicine Tel-Aviv 69978 Israel

This communication addresses the state of aggregation of lipid-detergent mixed dispersions. Analysis of recently published data suggest that for any given detergent-lipid mixture the most important factor in determining the type of aggregates (mixed vesicles or mixed micelles) and the size of the aggregate is the detergent to lipid molar ratio in these aggregates, herein denoted the effective ratio, Re. For mixed bilayers this effective ratio has been previously shown to be a function of the lipid and detergent concentrations and of an equilibrium partition coefficient, K, which describes the distribution of the detergent between the bilayers and the aqueous phase. We show that, similar to mixed bilayers, the size of mixed micelles is also a function of the effective ratio, but for these dispersions the distribution of detergent between the mixed micelles and the aqueous medium obeys a much higher partition coefficient. In practical terms, the detergent concentration in the mixed micelles is equal to the difference between the total detergent concentration and the critical micelle concentration (cmc). Thus, the effective ratio is equal to this difference divided by the lipid concentration. Transformation of mixed bilayers to mixed micelles, commonly denoted solubilization, occurs when the surfactant to lipid effective ratio reaches a critical value. Experimental evaluation of this critical ratio can be based on the linear dependence of detergent concentration, required for solubilization, on the lipid concentration. According to the ''equilibrium partition model'', the dependence of the ''solubilizing detergent concentration'' on the lipid concentration intersects with the lipid axis at -1/K, while the slope of this dependence is the critical effective ratio. On the other hand, assuming that when solubilization occurs the detergent concentration in the aqueous phase is approximately equal to the critical micelle concentration, implies that the above dependence inter

关键词： Membrane solubilization Detergent-membrane interaction Lipid bilayer Pc phosphatidylcholine L total lipid concentration D T total detergent concentration D b detergent concentration in bilayer D w detergent concentration in aqueous medium cmc critical micelle concentration K D b /LD w R e D b /L D T cmc the detergent concentrations D b cmc in the bilayer D w cmc D T c the detergent concentrations D b c in the bilayer R e cmc D b cmc /L R e c D b c /L ΔD T the detergent concentrations ΔD w in the water ΔD b bilayer D w cmc , to solubilize the lipids K′ ΔD b /LΔD w R H mean hydrodynamic radius of vesicles or micelles

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controls of carbon and nitrogen releases during crops' residue decomposition in the Red River Valley, USA

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ARcHIVES OF AGRONOMY AND SOIL ScIENcE 2020年第5期66卷 614-624页

作者： chatterjee, Amitava Acharya, Umesh North Dakota State Univ Dept Soil Sci Fargo ND 58108 USA

Decomposition of crop residue releases nutrients and preserves soil organic matter dynamics. The decomposition rates of six crop residues namely, corn (Zea mays), dry bean (Phaseolus vulgaris), soybean (Glycine max), potato (Solanum tuberosum), sugarbeet (Beta vulgaris) and spring wheat (Triticum aestivum), were studied at three field-sites: casselton, North Dakota, USA, and Ada and Downer of Minnesota, USA. Litterbags were placed on soil surface on 31 October 2016, and subset was retrieved after 6 months (8 April 2017) and finally after a year (30 October 2017). crop residue type had significant effect on remaining mass%, carbon (c) and nitrogen (N) release, and c:N ratio. After 1 year, remaining mass% followed the sequence of corn (82%) > soybean (74%) > wheat (72%) > dry bean (55%) > potato (40%) > sugarbeet (17%). Among sites, Ada had higher remaining biomass c and N than Downer but similar to casselton. Sugarbeet and corn had the highest (0.0054 d(-1)) and the lowest (0.0005 d(-1)) decomposition rate, respectively. Decomposition rate had a close relationship with initial residue c:N ratio. conversion to intensive corn-soybean rotation might increase the residue load on the surface and reduce c and N mineralization loss.

关键词： c N ratio remaining mass% mineralization

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cOMPARISON OF cERTAIN PROPERTIES OF MEMBRANE-BOUND AND SOLUBILIZED AcYLTRANSFERASE AcTIVITIES OF PLANT MIcROSOMES

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PLANT ScIENcE 1990年第1期69卷 39-48页

作者： FRENTZEN, M Institut fur Allgemeine Botanik Universität Hamburg Ohnhorststr. 18 D-2000 Hamburg 52 F.R.G.

Solubilized microsomal sn-glycerol-3-phosphate acyltransferase fractions were prepared by extracting membrane fractions from spinach leaves and etiolated pea seedlings with Tween 40 in the presence of Nacl. A comparison of the properties of the membrane bound sn-glycerol-3-phosphate acyltransferase and of the solubilized activity revealed that both enzymic forms displayed very similar fatty acid specificities and selectivities but different positional specificities. While the membrane bound enzyme directed the acyl groups to the c-1 position of sn-glycerol-3-phophate, the solubilized form catalyzed the acylation at the c-2 position. Moreover, in the microsomal fractions solublized with Tween 40 and 2-acyl-sn-glycerol-3-phopshate AT was detectable, which showed a pronounced selectivity for palmitoyl groups. On the other hand, when the microsomal membranes were extracted with Tween 80 instead of Tween 40, the sn-glycerol-3-phosphate acyltransferase of the resulting solubilized fractions displayed the same positional specificity as in the microsomal fractions. These results indicate that in contrast to the experiments with Tween 40, in which presumably latent activities wer induced, the extraction of microsomal membranes with Tween 80 resulted in the solubilization of at least part of the native sn-glycerol-3-phosphate acyltransferase.

关键词： acyltransferase solubilization monoacylglycerol-3-phosphate positional specificities 1-acylglycerol-3-P AT acyl-coA:1-acyl- sn -glycerol-3-phosphate acyltransferase (Ec 2.3.1.51) 2-acyl-glycerol-3-P AT acyl-coA:2-acyl- sn -glycerol-3-phosphate acyl transferase (Ec 2.3.1.-) glycerol-3-P sn -glycerol-3-phosphate glycerol-3-P AT acyl-coA: sn -glycerol-3-phosphate acyltransferase (Ec 2.3.1.15) monoacyl-glycerol-3-P monoacyl- sn -glycerol-3-phosphate Tween 40 (80) polyoxyethylen-sorbitan-monopalmitat (-monooleat) c 16:0 palmitoyl group c 18:1 oleoyl group

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Miniaturisation of Zn/Br redox flow battery cell and investigation of electrode materials influence on its characteristics

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MIcRO & NANO LETTERS 2016年第10期11卷 577-581页

作者： Nagai, Yoshiki Komiyama, Ryohei Miyashita, Hidetoshi Lee, Sang-Seok Tottori Univ Grad Sch Engn Tottori 6808552 Japan

Redox flow battery has been paid attention since it has been considered as a solution for large-scale energy storage. Among redox flow batteries, this work focuses on zinc (Zn)/bromine (Br) redox flow battery. The cell of Zn/Br redox flow battery as an energy source for a sensor node of wireless sensor network systems was miniaturised. Here, the fabrication and the experimental results for performance characteristics of the miniaturised Zn/Br redox flow battery cell are reported. Moreover, the electrode materials influence on its characteristics utilising four kinds of carbon materials such as activated carbon, hard charcoal, carbon nanotubes (cNTs), and activated carbon and cNTs composite was investigated. To investigate performance characteristics, charge-discharge tests, impedance measurement, specific surface area measurement, and charge and discharge cycling life test were performed. Moreover, the morphology of electrode materials was observed. As a result, it revealed that the activated carbon electrode showed the best coulombic efficiency of 88.6% and the largest specific surface area. Moreover, it was confirmed that the activated carbon and cNTs composite electrode material has the lowest inherent internal resistance and interfacial resistance among the investigated electrode materials. In the cycling life test, the cNTs electrode showed stable capacity retention during ten cycles.

关键词： flow batteries wireless sensor networks electrochemical electrodes zinc bromine charcoal activated carbon carbon nanotubes composite materials fuel cells redox flow battery cell electrode materials secondary batteries fuel cell active material energy storage zinc-bromine redox flow battery energy source sensor node wireless sensor network systems carbon materials hard charcoal carbon nanotubes cNT composite impedance measurement surface area measurement discharge cycling life test activated carbon electrode coulombic efficiency interfacial resistance Zn-Br c

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650 mW/mm output power density of H-terminated polycrystalline diamond MISFET at 10 GHz

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ELEcTRONIcS LETTERS 2020年第7期56卷 334-+页

作者： Yu, cui Zhou, chuang Jie Guo, Jian chao He, Ze Zhao Wang, Hong Xing cai, Shu Jun Feng, Zhi Hong Hebei Semicond Res Inst Natl Key Lab ASIC Shijiazhuang 050051 Hebei Peoples R China Xi An Jiao Tong Univ Sch Elect & Informat Engn Xian 710049 Peoples R China

In this work, metal-insulator-semiconductor field effect transistors (MISFET) with gate length of 350 nm were fabricated on hydrogen-terminated polycrystalline diamond by a self-aligned process. Aluminium film with thickness of 2 nm was evaporated on the sample and formed self-oxidised alumina to act as the gate dielectric. The devices show good direct current and radio frequency performances with a maximum frequency of oscillation (f(max)) of 34 GHz and continuous-wave output power density of 650 mW/mm at 10 GHz.

关键词： MISFET metal–insulator–semiconductor field effect transistors Al elemental semiconductors frequency 10.0 GHz gate dielectric continuous-wave output power density diamond O aluminium film self-oxidised alumina size 350.0 nm hydrogen-terminated polycrystalline diamond H-terminated polycrystalline diamond c alumina frequency 34.0 GHz size 2.0 nm direct current radio frequency performances

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MSVMpack: A Multi-class Support Vector Machine Package

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JOURNAL OF MAcHINE LEARNING RESEARcH 2011年 12卷 2293-2296页

作者： Lauer, Fabien Guermeur, Yann LORIA Equipe ABC F-54506 Vandoeuvre Les Nancy France

This paper describes MSVMpack, an open source software package dedicated to our generic model of multi-class support vector machine. All four multi-class support vector machines (M-SVMs) proposed so far in the literature appear as instances of this model. MSVMpack provides for them the first unified implementation and offers a convenient basis to develop other instances. This is also the first parallel implementation for M-SVMs. The package consists in a set of command-line tools with a callable library. The documentation includes a tutorial, a user's guide and a developer's guide.

关键词： multi-class support vector machines open source c

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Negative differential resistance in graphene nanoribbon superlattice field-effect transistors

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MIcRO & NANO LETTERS 2015年第8期10卷 400-403页

作者： chang, Sheng Zhao, Lei Lv, Yawei Wang, Hao Huang, Qijun He, Jin Wuhan Univ Minist Educ Sch Phys & Technol Key Lab Acoust & Photon Mat & Devices Wuhan 430072 Peoples R China

Different from researches in two-terminal nanoscale graphene structures, the negative differential resistance (NDR) phenomenon in graphene nanoribbon superlattice (GNSL) field-effect transistors (FETs) is studied in this reported work. Numerical analyses of two types of GNSL FETs with different gate voltages reveal that NDR occurs in some 'Z'-type GNSL FETs under some gate voltages, which develops NDR research compared with the traditional two-terminal nanoscale structures. Based on these results, two trends are observed: the 3m + 2 series GNSL FETs easily exhibit NDR, whereas it is more difficult to achieve this phenomenon with narrow FETs. This phenomenon is explained by the transmission coefficient as well as ab-initio calculations of the energy levels, where the entire channel of the FET is considered as a supercell. Through this analysis, the effect of gate control on energy-level localisation is uncovered, and a heterojunction-like explanation is proposed. This new explanation bridges the gap between a novel structure's physical analysis and the general semiconductor device concept, which can also provide inspiration for improving our understanding of novel nanostructure devices.

关键词： graphene superlattices nanoribbons field effect transistors ab initio calculations negative differential resistance graphene nanoribbon superlattice field-effect transistors two-terminal nanoscale graphene structures numerical analysis gate voltages Z-type GNSL FET transmission coefficient ab-initio calculations energy levels gate control effect energy-level localisation heterojunction-like explanation semiconductor device c

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Flexible capacitive pressure sensor based on multi-walled carbon nanotube electrodes

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MIcRO & NANO LETTERS 2017年第1期12卷 45-48页

作者： Shao, Na Wu, Jian Yang, Xing Yao, Jialin Shi, Yunsheng Zhou, Zhaoying Nanchang Hangkong Univ Sch Informat Engn Nanchang 330063 Jiangxi Peoples R China Tsinghua Univ Dept Precis Instruments Beijing 100084 Peoples R China Tsinghua Univ State Key Lab Precis Measurement Technol & Instru Beijing 100084 Peoples R China Nanchang Hangkong Univ Sch Aeronaut Mfg Engn Nanchang 330063 Jiangxi Peoples R China Mech Engn Coll Dept Elect & Optic Engn Hebei 050003 Peoples R China

Flexible pressure sensors offer the advantages of flexibility, low cost, and easy to large area fabrication, and they have wide applications in many fields. This work proposes a flexible capacitive pressure sensor that exhibits a sandwich-like structure, a good performance, and a simple process. Multi-walled carbon nanotube (MWNT) is used to fabricate the two electrodes of the sensor because this low cost material possesses good mechanical and electronic properties. Meanwhile, MWNT naturally forms numerous micro-nano structures that can enhance the sensitivity of a sensor. In addition, the dielectric layer of the sensor composed of parylene c (poly(chloro-p-xylylene)) is sandwiched between the two electrodes. The experimental results show that the pressure sensor demonstrates high sensitivity and a rapid response. The average sensitivity is 1.33 kPa (1) at a pressure that ranges from 0 to 758 Pa and the response time reach to millisecond level. Given that low cost, good property and simple process, the sensor has wide application prospects in electronic skins, health monitoring devices, and other wearable electronic products.

关键词： capacitive sensors capacitance measurement pressure sensors pressure measurement multi-wall carbon nanotubes nanosensors electrodes microsensors dielectric materials c pressure 0 Pa to 758 Pa wearable electronic product health monitoring device electronic skin poly(chloro-p-xylylene) parylene c dielectric layer micronano structure electronic property mechanical property MWNT sandwich-like structure multiwalled carbon nanotube electrode flexible capacitive pressure sensor

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cOEXISTENcE OF VARIABLE REGION OF IMMUNOGLOBULIN HEAVY-cHAIN AND I-REGION GENE-PRODUcTS ON ANTIGEN-SPEcIFIc SUPPRESSOR T-cELLS AND SUPPRESSOR T-cELL FAcTOR - A MINIMAL MODEL OF FUNcTIONAL ANTIGEN REcEPTOR OF T-cELLS

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MOLEcULAR IMMUNOLOGY 1980年第7期17卷 867-875页

作者： TADA, T HAYAKAWA, K OKUMURA, K TANIGUcHI, M CHIBA UNIV SCH MEDIMMUNOL LABSCHIBA 280JAPAN

Antigen-binding T cells were semipurified from splenic T cells from mice primed with keyhole limpet hemocyanin (KLH) ? by adsorption to and elution from KLH-coated Petri dishes. These celts were characterized by the cytotoxic assay with various xeno- and alloantisera against membrane components of lymphocytes. About 30-80% of KLH-binding T cells were killed with an antiserum against the products of the I-J subregion of mouse major histocompatibility complex (anti-I-J). comparable numbers of T cells were also killed by rabbit antibodies reactive to the framework structure of heavy chain variable domain (anti-V_H). The antibodies against V region framework of light chain (anti-V_L) were unable to kill antigen-binding T ceils. No cytotoxicity was observed with antibodies against constant structures of mouse immunoglobulins (anti-MIg). All these antisera failed to kill significant numbers of non-antigen-binding T cells. Furthermore, anti-V_H was able to stain antigen-binding T cells in immunofluorescence. Antigen-specific suppressor T cell factor (TsF) derived from antigen-primed suppressor T ceils was successfully removed by a passage through anti-V_H, but not anti-V_L columns, and waseluted from the anti-V_H column by an acid treatment. The factor was also absorbed by an anti-I-J immunoadsorbent. A similar V_H- and I-J-bearing factor was also produced by hybridoma cell lines made by fusion between antigen-binding T cells and a lymphoma cell line, BW5147. These results indicate that the antigen receptor of suppressor T cells is composed of two discrete gene products, one being coded for by a gene of immunoglobulin linkage group and the other by an I region gene. circumstantial evidence that the molecule in fact consists of two chains is also presented. On the above basis, a minimal model of functional T cell receptors for antigen is discussed in the light of regulatory interactions between different

关键词： β 2 μ β 2 microglobulin c rabbit complement cH heavy chain constant region DNP 2,4-dinitrophenyl FAcS fluorescence activated cell sorter FcS fetal calf serum Ia I region associated antigen Ig immunoglobulin(s) KLH keyhole limpet hemocyanin MEM Eagle's minimal essential medium MHc major histocompatibility complex PFc plaque forming cell T cell thymus-derived lymphocytes TaF antigen-specific augmenting T cell factor TsF antigen-specific suppressor T cell factor VH variable domain of immunoglobulin heavy chain V L variable domain of immunoglobulin light chain

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caenorhabditis elegans glp-4 Encodes a Valyl Aminoacyl tRNA Synthetase

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G3-GENES GENOMES GENETIcS 2015年第12期5卷 2719-2728页

作者： Rastogi, Suchita Borgo, Ben Pazdernik, Nanette Fox, Paul Mardis, Elaine R. Kohara, Yuji Havranek, Jim Schedl, Tim Washington Univ Sch Med Dept Genet St Louis MO 63110 USA Natl Inst Genet Mishima Shizuoka 4118540 Japan

Germline stem cell proliferation is necessary to populate the germline with sufficient numbers of cells for gametogenesis and for signaling the soma to control organismal properties such as aging. The caenorhabditis elegans gene glp-4 was identified by the temperature-sensitive allele bn2 where mutants raised at the restrictive temperature produce adults that are essentially germ cell deficient, containing only a small number of stem cells arrested in the mitotic cycle but otherwise have a morphologically normal soma. We determined that glp-4 encodes a valyl aminoacyl transfer RNA synthetase (VARS-2) and that the probable null phenotype is early larval lethality. Phenotypic analysis indicates glp-4(bn2ts) is partial loss of function in the soma. Structural modeling suggests that bn2 Gly296Asp results in partial loss of function by a novel mechanism: aspartate 296 in the editing pocket induces inappropriate deacylation of correctly charged Val-tRNA(val). Intragenic suppressor mutations are predicted to displace aspartate 296 so that it is less able to catalyze inappropriate deacylation. Thus glp-4(bn2ts) likely causes reduced protein translation due to decreased levels of Val-tRNA(val). The germline, as a reproductive preservation mechanism during unfavorable conditions, signals the soma for organismal aging, stress and pathogen resistance. glp-4(bn2ts) mutants are widely used to generate germline deficient mutants for organismal studies, under the assumption that the soma is unaffected. As reduced translation has also been demonstrated to alter organismal properties, it is unclear whether changes in aging, stress resistance, etc. observed in glp-4(bn2ts) mutants are the result of germline deficiency or reduced translation.

关键词： glp-4 valine-tRNA synthetase c elegans germline aging stress resistance

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