Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)最新文献_第9页

The voltammetric behavior of bone marrow of leukaemia and its clinical application 白血病骨髓的伏安行为及其临床应用

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-02-01 DOI: 10.1016/S0302-4598(98)00218-9

Huai-Na Li , Yun-Xiang Ci , Jun Feng , Kang Cheng , Shuang Fu , De-Bing Wang

引用次数: 29

Charged microbeads are not transported across the human stratum corneum in vitro by short high-voltage pulses 在体外实验中，带电微珠不能通过短的高压脉冲穿越人角质层

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-02-01 DOI: 10.1016/S0302-4598(99)00007-0

Tani Chen , Robert Langer , James C Weaver

引用次数: 14

Fast reversible electron transfer for photosynthetic reaction center from wild type Rhodobacter sphaeroides re-constituted in polycation sandwiched monolayer film 野生型球形红杆菌在聚阳离子夹层膜中进行光合反应中心的快速可逆电子转移

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-02-01 DOI: 10.1016/S0302-4598(98)00234-7

Jilie Kong , Wenliang Sun , Xingliang Wu , Jiaqi Deng , Zhongqing Lu , Yuri Lvov , Roel Z.B Desamero , Harry A Frank , James F Rusling

{"title":"Fast reversible electron transfer for photosynthetic reaction center from wild type Rhodobacter sphaeroides re-constituted in polycation sandwiched monolayer film","authors":"Jilie Kong , Wenliang Sun , Xingliang Wu , Jiaqi Deng , Zhongqing Lu , Yuri Lvov , Roel Z.B Desamero , Harry A Frank , James F Rusling","doi":"10.1016/S0302-4598(98)00234-7","DOIUrl":"10.1016/S0302-4598(98)00234-7","url":null,"abstract":"<div><p>Direct reversible electron transfer for photosynthetic reaction center from wild type <em>Rhodobacter sphaeroides</em> re-constituted in polycation sandwiched monolayer film was observed in this work. The redox potential <em>E</em><sup>0</sup>′=0.46 V vs. NHE for first primary donor redox couple P/P<sup>+</sup> was accurately measured from reversible CV or SWV peaks, which were quite close to those obtained from optic redox titration method. Reaction center (RC) in film was found re-constituted in such an ordered way that the orientation of RC favored the electron transfer in film. Thus, the protein electroactivity seems to be turned on in this artificial biomimic thin film. Furthermore, RC in the film features a photo-induced redox-peak fluctuation, suggesting an intact and functional state for RC in such film. Redox peaks were also found dependent of pH, implying a proton-coupled electron transfer occurring in film. Charge recombination was observed accompanied with change of electrochemical driving force. Electrochemical model assuming several classes of electroactive sites in the films on the electrode with a dispersion of standard potentials successfully fits SWV experimental data at different pulse height and frequency.</p></div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"48 1","pages":"Pages 101-107"},"PeriodicalIF":0.0,"publicationDate":"1999-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(98)00234-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21098288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 20

Modeling the surface phenomena in carbon paste electrodes by low frequency impedance and double-layer capacitance measurements 利用低频阻抗和双层电容测量模拟碳糊电极的表面现象

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-02-01 DOI: 10.1016/S0302-4598(98)00227-X

D Savitri, Chanchal K Mitra

引用次数: 15

Direct electron transfer for hemoglobin in biomembrane-like dimyristoyl phosphatidylcholine films on pyrolytic graphite electrodes 热解石墨电极上生物膜样二肉豆醇磷脂酰胆碱膜中血红蛋白的直接电子转移

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-02-01 DOI: 10.1016/S0302-4598(98)00222-0

Jing Yang, Naifei Hu

{"title":"Direct electron transfer for hemoglobin in biomembrane-like dimyristoyl phosphatidylcholine films on pyrolytic graphite electrodes","authors":"Jing Yang, Naifei Hu","doi":"10.1016/S0302-4598(98)00222-0","DOIUrl":"10.1016/S0302-4598(98)00222-0","url":null,"abstract":"<div><p>Stable thin films made from dimyristoyl phosphatidylcholine (DMPC) with incorporated hemoglobin (Hb) on pyrolytic graphite (PG) electrodes were characterized by electrochemical and other techniques. Cyclic voltammetry (CV) of Hb-DMPC films showed a pair of well-defined and nearly reversible peaks at about −0.27 V vs. saturated calomel electrode (SCE) at pH 5.5, characteristic of Hb heme Fe(III)/Fe(II) redox couple. The electron transfer between Hb and PG electrodes was greatly facilitated in DMPC films. Apparent heterogeneous rate constants (<em>k</em><sub>s</sub>) were estimated by fitting square wave voltammograms of Hb-DMPC films to a model featuring thin layer behavior and dispersion of formal potentials for redox center. The formal potential of Hb heme Fe(III)/Fe(II) couple in DMPC films shifted linearly between pH 4.5 to 11 with a slope of −48 mV pH<sup>−1</sup>, suggesting that one proton is coupled to each electron transfer in the electrochemical reaction. Soret absorption band positions suggest that Hb retains a near native conformation in DMPC films at medium pH. Differential scanning calorimetry (DSC) showed the phase transition for DMPC and Hb-DMPC films, suggesting DMPC has an ordered multibilayer structure. Trichloroacetic acid (TCA) was catalytically reduced by Hb-DMPC films with significant decreases in the electrode potential required.</p></div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"48 1","pages":"Pages 117-127"},"PeriodicalIF":0.0,"publicationDate":"1999-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(98)00222-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21098290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 113

Classification of organic molecules to obtain electron affinities from half-wave reduction potentials: cytosine, uracil, thymine, guanine and adenine 从半波还原电位获得电子亲和的有机分子分类:胞嘧啶、尿嘧啶、胸腺嘧啶、鸟嘌呤和腺嘌呤

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-02-01 DOI: 10.1016/S0302-4598(98)00211-6

Edward S.D Chen , Edward C.M Chen , Neeta Sane , Shawn Shulze

引用次数: 27

Is the Ca2+ transport of human erythrocytes influenced by ELF- and MF-electromagnetic fields? 低频电磁场和高频电磁场对人红细胞Ca2+转运有影响吗?

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1998-12-01 DOI: 10.1016/S0302-4598(98)00204-9

R Glaser, M Michalsky, R Schramek

{"title":"Is the Ca2+ transport of human erythrocytes influenced by ELF- and MF-electromagnetic fields?","authors":"R Glaser, M Michalsky, R Schramek","doi":"10.1016/S0302-4598(98)00204-9","DOIUrl":"10.1016/S0302-4598(98)00204-9","url":null,"abstract":"<div><p>In about 400 double experiments, the influence of electromagnetic fields between 15 Hz and 12 kHz on the active calcium pump (Ca,Mg-ATPase) of human erythrocytes was investigated. Each experiment includes the fitting of the efflux kinetics synchronously in two identical equipments, with two parts of the same erythrocyte suspension, one with field, one as untreated control. No clear effect on the activity of the Ca,Mg-ATPase of human erythrocytes could be found, neither for magnetic sinusoidal fields up to 2.6 mT (peak), nor for AC fields supported by a static magnetic field (3.9 mT SMF+3.9 mT, 1 kHz), nor for directly applied electric fields up to 150 V/m. The Arrhenius plot of the rate constants show a transition at 23°C, but no temperature-dependent field effect could be found. Several points, supported by 10 to 20 experiments show a small, but significant decrease in the rate constant of the efflux (45 Hz, 740 Hz, 1040 Hz), but this could not be confirmed by experiments at 620, 920 and 1540 Hz. The statistical deviation of the field effects in the region between 520 and 1540 Hz of the experiments with magnetic fields are significantly larger than for experiments with other frequencies and from such with the electrode system, whereas the deviation of the rate constants themselves are always the same.</p></div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"47 2","pages":"Pages 311-318"},"PeriodicalIF":0.0,"publicationDate":"1998-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(98)00204-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74136903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

High magnetic field effects on human deoxygenated hemoglobin light absorption 强磁场对人体脱氧血红蛋白光吸收的影响

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1998-12-01 DOI: 10.1016/S0302-4598(98)00165-2

Mauricy Motta , Yousef Haik , Abolghasem Gandhari , Ching-Jen Chen

引用次数: 50

Information encoding in the temporal aspects of electromagnetic fields consequent to human cortical neuronal activation 电磁场在时间方面的信息编码是人类皮层神经元激活的结果

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1998-12-01 DOI: 10.1016/S0302-4598(98)00198-6

Timothy P.L. Roberts

{"title":"Information encoding in the temporal aspects of electromagnetic fields consequent to human cortical neuronal activation","authors":"Timothy P.L. Roberts","doi":"10.1016/S0302-4598(98)00198-6","DOIUrl":"10.1016/S0302-4598(98)00198-6","url":null,"abstract":"<div><p>This study investigates the temporal signature of neuronal responses to auditory stimuli and, specifically, encoding of pitch and timbre characteristics in the auditory evoked neuromagnetic field. Recordings are made with a 37-channel biomagnetometer with stimuli consisting of (a) sinusoidal waves, (b) square waves, (c) amplitude-modulated (AM) sine waves and (d) synthesized speech sounds. For (a) and (b), frequencies in the range 100–5000 Hz were examined. For the AM sounds, a carrier frequency of 500–1500 Hz was used with 100 Hz and 200 Hz modulation. Speech sounds of pseudo-male and pseudo-female utterance were used. All stimuli elicited neuromagnetic fields characterized by distinct peaks of coherent activity approximately 100 ms post-stimulus (M100). Source localization estimates indicated that all neuronal sources lay in the superior temporal gyrus. However, no tonotopic organization was resolvable. For sine-wave tones, frequency-dependence of the M100 latency was detected, being up to 30 ms longer at low frequencies, and largely invariant from 1000–5000 Hz. This effect was mimicked using square-wave tones, although the magnitude of latency shift was attenuated to 15 ms. AM and speech sounds demonstrated M100 latencies more characteristic of carrier frequency and formants rather than modulation frequency and fundamental, respectively. Information is encoded in the time domain of neuronal response to auditory stimulation. The frequency of a stimulus gives rise to a specific latency of neuronal coherence. Timbre is also encoded, since more complex sounds give rise to latencies reflecting their spectral energy distribution. High temporal resolution recording of electromagnetic activity allows new insights into the brain's functional encoding of stimulus attributes.</p></div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"47 2","pages":"Pages 265-271"},"PeriodicalIF":0.0,"publicationDate":"1998-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(98)00198-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73624500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Dielectric properties of rat liver in vivo: a noninvasive approach using an open-ended coaxial probe at audio/radio frequencies 活体大鼠肝脏的介电特性:在音频/无线电频率下使用开放式同轴探针的无创方法

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1998-12-01 DOI: 10.1016/S0302-4598(98)00171-8

V Raicu , T Saibara , A Irimajiri

{"title":"Dielectric properties of rat liver in vivo: a noninvasive approach using an open-ended coaxial probe at audio/radio frequencies","authors":"V Raicu , T Saibara , A Irimajiri","doi":"10.1016/S0302-4598(98)00171-8","DOIUrl":"10.1016/S0302-4598(98)00171-8","url":null,"abstract":"<div><p>To characterize the passive electrical properties of liver cells in vivo, we measured the frequency dependence of relative permittivity and conductivity for rat liver lobes in situ by means of a noninvasive surface probe coupled with a fast impedance analyzer, covering the frequency range 10<sup>2</sup>–10<sup>8</sup> Hz. Securing a stable contact, mechanical as well as electrochemical, between the probe and tissue surface both wetted with physiological saline, made it possible to collect a highly reproducible set of data even from lobes undergoing respiratory movement in situ. The data obtained traced a broad dielectric dispersion curve over the range 10<sup>3</sup>–10<sup>8</sup> Hz, suggestive of the involvement of widely distributed relaxation times. As its theoretical analyses based on cell membrane models are made in a companion paper [V. Raicu, T. Saibara, H. Enzan, A. Irimajiri, Dielectric properties of rat liver in vivo: analysis by modeling hepatocytes in the tissue architecture, Bioelectrochem. Bioenerg. 47 (1998) 333–342.], this report describes experimental conditions required for reliable measurements on a well-defined superficial region of viable liver lobes. The most important factors among these are the tissue surface condition such as `wet' or `dry' and the effective penetration depth of field lines defined by the probe's geometric characteristics.</p></div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"47 2","pages":"Pages 325-332"},"PeriodicalIF":0.0,"publicationDate":"1998-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(98)00171-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74654331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 61