bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glucosensing neurons in the ventromedial hypothalamic nucleus (VMN) and hypoglycemia‐associated autonomic failure (HAAF)
Authors: Routh Vanessa H. 
Published: September 2003

AbstractHypoglycemia is a profound threat to the brain since glucose is its preferred fuel. Thus, decreases in plasma glucose must be sensed and appropriate hormonal and neuroendocrine responses generated to restore glucose to safe levels (i.e. counterregulatory responses (CRR) to hypoglycemia). Recurrent hypoglycemia impairs these protective mechanisms, resulting in a potentially life‐threatening condition known as hypoglycemia‐associated autonomic failure (HAAF). During HAAF, the glycemic threshold is reset so that glucose levels must fall further before the CRR is initiated. The brain plays a critical role in sensing hypoglycemia and initiating the CRR. Additionally, many neurons may sense changes in plasma and extracellular glucose. However, the way in which central glucose sensing is integrated to lead to effective initiation of the CRR is unknown. Furthermore, the mechanisms by which this system becomes impaired during HAAF are also unknown. Glucosensing neurons in the ventromedial hypothalamic nucleus (VMN) are poised to serve an integrative function in glucose homeostasis. First, they sense glucose. Second, the VMN receives input from other glucose‐sensing areas. Finally, the VMN projects to areas linked to the regulation of the sympathoadrenal system that mediates the CRR. This review discusses VMN glucosensing neurons relative to their capacity to play a role in the regulation of the CRR and the generation of HAAF. Glucosensing neurons in the hindbrain as well as peripheral glucosensors are also considered. Copyright © 2003 John Wiley & Sons, Ltd.
Improved glycaemic control in type 1 diabetes patients following participation per se in a clinical trial—mechanisms and implications
Authors: DeVries J. Hans , Snoek Frank J. , Kostense Piet J. , Heine Robert J. 
Published: September 2003

AbstractThe phenomenon of improved diabetes self‐management following participation in a clinical trial, with subsequent improvement of glycaemic control, has been acknowledged in literature but has received little attention. Also, the potential implications of such a ‘study effect’ for clinical research are poorly explored.We review the literature and describe the effects on glycaemic and psychological outcomes in long‐term poorly controlled type 1 diabetes patients participating in a qualification phase of a Good Clinical Practice (GCP) trial. Improved glycaemic control following participation in a clinical trial is best understood as the result of improved patients' instrumental coping behaviours, including increased self‐monitoring of blood glucose (SMBG). Such improvement in self‐care with ensuing improved glycaemic control has important consequences for trial design. Firstly, benefits seen in uncontrolled trials should be interpreted with extreme caution. Secondly, unspecific study effects and the effect of a given intervention may not simply be additive. Therefore, it is wise to include a run‐in or qualification phase of adequate length before randomization in a clinical trial. A stable baseline HbA1c can thus be reached, upon which the specific effect of an intervention can be properly judged. Also, in a multi‐centre trial, a qualification phase of sufficient length will help diminish differences in terms of intensity of care provided in participating centres. Copyright © 2003 John Wiley & Sons, Ltd.
Development of cell markers for the identification and expansion of islet progenitor cells
Authors: Zhang You‐Qing , Sarvetnick Nora 
Published: September 2003

AbstractDiabetes mellitus results from the anatomical or functional loss of insulin‐producing beta cells of the pancreas. Despite significant advances in current treatment, patients with diabetes still do not maintain optimal glucose levels and therefore face debilitating complications such as hypoglycemia, retinopathy or cardiovascular diseases later in life. Islet transplantation therefore holds great promise as an ultimate cure for diabetes. However, the shortage of availability of donor sources of islets for transplantation has largely hampered this therapy. In this respect, the use of alternative sources of islets such as the ex vivo culture and expansion and differentiation of functional endocrine cells for treating diabetes has been a major focus of diabetes research. The identity of the islet stem/progenitor cells has remained either elusive or at least equivocal because of the lack of cell markers for identification of these cells. Recent successes in studying the organogenesis of pancreas as well as in vitro islet progenitor cell identification studies have provided tremendous insight for the cell markers that are essential in the isolation and characterization of these cells prospectively both in vivo and in vitro. If we can identify the markers that will aid the isolation and purification of islet progenitor cells, or factors that determine pancreatic cell fate, we might be able to coerce them from turning into specific endocrine cells or pancreas in vitro. This article will focus on this subject and will review the latest achievements in the study of cell markers for islet progenitor cells. Copyright © 2003 John Wiley & Sons, Ltd.
A photoacoustic study of thermal conductivity annealing curves for a silicon substrate implanted with Si ions
Authors: Takabatake Nobuya , Kobayashi Takeshi , Show Yoshiyuki , Izumi Tomio 
Published: September 2003

AbstractRecrystallization by annealing is part of the processing of ion‐implanted semiconductor substrates because the ion implantation generates defects within the crystal. Furthermore, it was reported by Zammit's group [1] that the thermal conductivity of such substrates deteriorates remarkably after implantation. In light of these facts, we have analyzed the photoacoustic signal from a thin layer fabricated on a substrate by ion implantation, and have used the data to measure the thermal conductivity of the implanted layer in the depth direction. Our thermal conductivity measurements can be used to monitor the recrystallization of the implanted layer in the course of the annealing. We fabricated the samples by implanting Si ions into a region on top of a Si substrate at room temperature. The ions used in the implantation had an energy of 150 keV. The ion implantation doses were in the range from 1 × 1012 to 1 × 1016ions/cm2. The thickness of the ion‐implanted layer was measured by TEM to be 100 nm. By detecting the difference between the phases of photoacoustic signals coming from the ion‐implanted region and from the unimplanted region, we could extract the thermal conductivity of the implanted layer from the frequency modulation characteristics of this phase difference. We used this technique to measure annealing curves for the thermal conductivity. Our results indicated that in the course of restoring the crystallinity, the thermal conductivity begins to increase at about 500 °C, and by 750 °C it has recovered to almost the same value as prior to the implantation. Our measured annealing curves for the thermal conductivity correlated strongly with measurement data on the annealing curves of the ESR signal intensity from the same samples. This result makes it clear that measurement of the thermal conductivity by the photoacoustic method is an efficient way to monitor the defect density in implanted layers. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(10): 1–8, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10034
Network design for streaming service on IP multicast over ATM
Authors: Sugisono Koji , Yamamoto Miki , Ikeda Hiromasa 
Published: September 2003

AbstractThis paper considers streaming service, which is an application of multicast communications, and discusses the network configuration used in providing IP multicast over ATM. In IP multicast over ATM, conversion from the IP multicast address to the ATM address is required. One of the methods of making this conversion is to use a multicast address resolution server (MARS). In this system, the MARS manages the member information of the multicast group. When there is a change in the membership of the group because a host joins or leaves, that host sends an information renewal message to the MARS. In streaming service, there arises a time zone in which many renewal messages to MARS are generated due to program changes and the like, so that the MARS is heavily burdened. This paper considers the case in which streaming service is introduced via MARS, and analytically derives the transmission frequency of the information renewal messages. The relations between the transmission frequency, the characteristics of the program, and the network scale are identified. Based on the results of analysis and a consideration of the effect of other traffic on the network, an adequate network design principle capable of reducing the control traffic to the MARS is presented. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 86(10): 51–59, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10188
Contingency selection method for on‐line small signal stability monitoring
Authors: Takimoto Akira , Uchida Naoyuki 
Published: September 2003

AbstractTo make greater use of existing electric power transmission facilities, security assessment utilizing on‐line data is thought to be one of the effective measures that can be taken. To realize on‐line assessment of postfault small signal stability for a number of supposed contingencies, it is effective to identify severe contingencies to be analyzed with a precise assessment program, such as the S‐method. We developed a contingency selection method that has two indices for selection.One of the indices is postfault eigenvalue estimation based on second‐order approximation of the eigenvalue change in response to system matrix change, which is effective for relatively weak nonlinear eigenvalue change. The other one is the Nonlinearity index, which indicates the strength of nonlinearity eigenvalue change. It is effective in detecting strong nonlinear eigenvalue changes that cannot be estimated correctly by second‐order approximation.Calculation results with IEEJ Bulk Power System Models show that the proposed method can effectively decrease the number of contingencies that must be analyzed by the precise Small Signal Analysis method. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(4): 20–27, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10186
Continuous monitoring of developmental activity changes in cultured cortical networks
Authors: Mukai Yoshitaka , Shiina Tsuyoshi , Jimbo Yasuhiko 
Published: September 2003

AbstractDuring development, cortical neurons show highly synchronized spontaneous activity. This spontaneous activity probably reflects the mechanisms underlying proper network formation regulated by activity‐dependent synaptic modification. To see long‐term transitions in this spontaneous activity, we constructed a microelectrode‐array (MEA)‐based continuous monitoring system. Rat cortical neurons were cultured on MEAs with 64 embedded electrodes and maintained in a conventional CO2 incubator. A perfusion system for medium changes and recording setup for electrical signals were directly connected to the MEA in the incubator. Culture medium was continuously perfused at a very slow rate (0.1 ml/h), which was quite effective at maintaining constant conditions without contamination. Using this system, we succeeded in recording spontaneous activity of cultured cortical networks, almost continuously from 5 days to more than 1 month in vitro. It was revealed that the spontaneous activity patterns showed transition from simple synchronized bursts to a complex mixture of multiple patterns, separated by a brief silent period at approximately 2 weeks in vitro. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(4): 28–37, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10216
Estimation of the number of EEG sources in the human brain using multidimensional directed information analysis
Authors: Sakata Osamu , Shiina Tsuyoshi , Saito Yoichi 
Published: September 2003

AbstractAt present, various approaches are being used to analyze brain function. One of these is the analysis of EEGs (electroencephalogram), by which it is becoming possible to evaluate brain activity and abnormalities in the brain from the EEG observed on the scalp. There remain many unknown aspects of the source of EEGs and their mechanism of propagation. A clue to such an approach is causality analysis, whose objective is to analyze causality by quantifying correlation relations, including the directions of information flow, among measurement sites, based on multiple EEG series obtained from multiple sites on the scalp. The method should be applicable to the diagnosis of disease such as the detection of individual abnormalities and failure of information propagation. Consequently, we have proposed multidimensional directed information analysis as a means of causality analysis in which the flow of information among all signals is investigated.There are many multidimensional signals in nature, for which the number of information flow sources in unknown. It is very important to discover the number of sources. Therefore, we propose a method to estimate the number of information flow sources by multidimensional directed information analysis. In this paper, the effectiveness of the proposed method has been verified by a simulation, and the method has been applied to the EEG of a healthy subject and a patient with a cerebral organic disorder. As a result, we have found that the healthy subject had six information flow sources and the patient had nine. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(4): 38–45, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10218
Instability and chopping phenomena of a low‐current vacuum arc
Authors: Ding Cuie , Yanabu Satoru , Satoaki Arai 
Published: September 2003

AbstractIn order to elucidate instability and chopping phenomena at low current in a vacuum, we observed the phenomena while varying such parameters as the arcing time, the breaking current, the gap distance, and the parallel circuit parameters. We measured the instability initiation current, chopping current, arc voltage, arc voltage oscillation peak, and transient recovery voltage values using copper, copper chromium, and silver tungsten carbide electrodes.It was found that the instability initiation current and the chopping current increased with increasing arcing time and decreased with increasing breaking current amplitude and gap size. In addition, the chopping current, the arc voltage oscillation peak, and the transient recovery voltage were dependent on the parallel circuit parameters, but the instability initiation current and the arc voltage were not dependent on them. We also found that the instability phenomena depended primarily on the cathode material. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(4): 12–19, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10224
Analysis of magnetic saturation in a salient‐pole synchronous machine after sudden three‐phase short circuit
Authors: Shima Kazuo , Ide Kazumasa , Takahashi Miyoshi 
Published: September 2003

AbstractIn order to evaluate magnetic saturation under subtransient and transient states of a large‐sized salient‐pole synchronous machine, the currents and leakage inductances after sudden three‐phase short circuits are analyzed by a two‐dimensional nonlinear transient finite element method (FEM). The currents are calculated both by direct and indirect methods. The direct method uses the FEM and considers fluctuation of the magnetic saturation after the short circuit. The indirect method solves Park's differential equations without fluctuation. Results of the direct method agree well with measurements. When the preshort voltage is large, fluctuation of the leakage inductances after the short is large and it greatly affects values of the short‐circuit currents. As the preshort voltage becomes large, the damper leakage inductances saturate at first, then the field leakage inductances, and finally the armature leakage inductances saturate. Although the indirect method considers saturation under the preshort condition, it gives inaccurate results and they are nearly the same as the results by the linear FEM. In general, it is thought that saturation of the leakage flux should be considered when subtransient conditions with large disturbance are analyzed. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 145(4): 46–55, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10240
Targeting Chemical and Biological Warfare Agents at the Molecular Level
Authors: Sadik Omowunmi A. , Land Walker H. , Wang Joseph 
Published: September 2003

AbstractAfter the September 11 tragedies of 2001, scientists and law‐enforcement agencies have shown increasing concern that terrorist organizations and their “rogue” foreign government‐backers may resort to the use of chemical and/or biological agents against U.S. military or civilian targets. In addition to the right mix of policies, including security measures, intelligence gathering and training for medical personnel on how to recognize symptoms of biochemical warfare agents, the major success in combating terrorism lies in how best to respond to an attack using reliable analytical sensors. The public and regulatory agencies expect sensing methodologies and devices for homeland security to be very reliable. Quality data can only be generated by using analytical sensors that are validated and proven to be under strict design criteria, development and manufacturing controls. Electrochemical devices are ideally suited for obtaining the desired analytical information in a faster, simpler, and cheaper manner compared to traditional (lab‐based) assays and hence for meeting the requirements of decentralized biodefense applications. This articler presents a review of the major trends in monitoring technologies for chemical and biological warfare (CBW) agents. It focuses on research and development of sensors (particularly electrochemical ones), discusses how advances in molecular recognition might be used to design new multimission networked sensors (MULNETS) for homeland security. Decision flow‐charts for choosing particular analytical techniques for CBW agents are presented. Finally, the paths to designing sensors to meet the needs of today's measurement criteria are analyzed.
A Microbial Biosensor for p‐Nitrophenol Using Arthrobacter Sp.
Authors: Lei Yu , Mulchandani Priti , Chen Wilfred , Wang Joseph , Mulchandani Ashok 
Published: September 2003

AbstractThis article reports the construction, optimization of performance variables and analytical characterization of a sensitive and selective microbial amperometric biosensor for measurement of p‐nitrophenol (PNP), a U.S. Environmental Agency priority pollutant. The biosensor consisted of PNP‐degrading/oxidizing bacteria Arthrobacter sp. JS443 as biological sensing element and a dissolved oxygen electrode as the transducer. The best sensitivity and response time were obtained using a sensor constructed with 1.2 mg dry wt. of cells and operating in pH 7.5, 50 mM citrate‐phosphate buffer. Using these conditions, the biosensor was able to measure as low as 28 ppb (0.2 μM) of PNP selectively without interference from structurally similar compounds, such as phenol, nitrophenols and chlorophenols. The service life of the microbial biosensor is around 5 days when stored in the operating buffer at 4 °C. The applicability to lake water is demonstrated.
Multilayer Assemblies Consisting of Tri‐Vanadium‐Substituted Heteropolyanions and Its Electrocatalytic Properties
Authors: Zhai Shengyong , Liu Jianyun , Jiang Junguang , Dong ShaoJun 
Published: September 2003

AbstractWe describe the controlled fabrication of ultrathin multilayer films consisting of tri‐vanadium‐ substituted heteropolytungstate anions (denoted as P2W15V3) and a cationic polymer of quaternized poly (4‐vinylpyridine) partially complexed with osmium bis(2,2′‐bipyridine) (denoted as QPVP‐Os) on the 4‐aminobenzoic acid (4‐ABA) modified glassy carbon electrode (GCE) surface based on layer‐by‐layer assembly. Cyclic voltammetry and UV‐vis absorption spectrometry have been used to easily monitor the thickness and uniformity of thus‐formed multilayer films. The V‐centered redox reaction of P2W15V3 in the multilayer films can effectively catalyze the reduction of BrO$\rm{ {_{3}^{-}}}$ and NO$\rm{ {_{2}^{-}}}$. The resulting P2W15V3/QPVP‐Os multilayer film modified electrode behaves as a much promising electrochemical sensor because of the low overpotential for the catalytic reduction of BrO$\rm{ {_{3}^{-}}}$ and NO$\rm{ {_{2}^{-}}}$, and the catalytic oxidation of ascorbic acid.
Flow Injection Analysis of Ascorbic Acid in Real Samples Using a Highly Stable Chemically Modified Screen‐Printed Electrode
Authors: Zen Jyh‐Myng , Tsai Dong‐Mung , Senthil Kumar Annamalai 
Published: September 2003

AbstractA silica sol‐gel glass‐coated ferricyanide‐doped Tosflex‐modified screen‐printed electrode (designated as SG/FeCN‐Ts/SPE) was used for the mediated oxidation of ascorbic acid in neutral pH. The sol‐gel overlayer was found to stabilize the Fe(CN)$\rm{ {_{6}^{3-}}}$‐Tosflex system without any foul‐off and deterioration behavior through chemical interaction between the hydrophilic sites of Tosflex and oxy‐ and/or ‐hydroxy surface functional groups of silicate. The electrochemical mediation of ascorbic acid was found to follow the Michaelis‐Menten kinetic pathway. The SG/FeCN‐Ts/SPE was very stable for repetitive measurements by flow injection analysis at 0.3 V (vs. Ag/AgCl). A linear calibration plot was obtained for ascorbic acid determination up to 300 μM with sensitivity and detection limit (S/N=3) of 2.85 nA/μM and 46 nM, respectively. The system also showed tolerable interference to uric acid, urea and carbohydrates and was used for the determination of ascorbic acid in human urine, clinical tablet and apple juice.
Differential Pulse Polarography of the Zn2+ Complexation by Glutathione Fragments Cys‐Gly and gamma‐Glu‐Cys
Authors: Cruz Vásquez Boris H. , Díaz‐Cruz José Manuel , Ariño Cristina , Esteban Miquel 
Published: September 2003

AbstractThe metal binding properties of glutathione (GSH) and their fragments γ‐Glu‐Cys and Cys‐Gly are of biological and environmental interest. In this work a differential pulse polarographic study of the Zn2+/γ‐Glu‐Cys and Zn2+/Cys‐Gly systems was carried out for a better understanding of the results obtained in previous studies on the Zn2+‐GSH system. In the case of γ‐Glu‐Cys, complexation with Zn2+ was not detected. In the case of Cys‐Gly, the parallel analysis, by multivariate curve resolution with alternating least squares, of data from the titration of peptide with metal and of metal with peptide suggested the presence of two types of bound Zn2+. This could be attributed to Zn2+ strongly bound to two sulfur atoms of two peptides, to form a complex of 1 : 2 stoichiometry, and to Zn2+ weakly bound to carboxylate and/or amino groups.