bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modulation by adenosine A2A receptors of dopamine‐mediated motor behavior as a basis for antiparkinson’s disease drugs
Authors: Morelli Micaela , Pinna Annalisa 
Published: August 2002

AbstractSeveral studies have evidenced the opposite role played by dopamine and adenosine receptors in the control of motor behavior. In line with those studies, we have previously shown that the acute administration of the A2A receptor antagonist SCH 58261 potentiated the turning behavior induced by L‐DOPA in the unilateral 6‐hydroxydopamine (6‐OHDA) rat model of Parkinson’s disease (PD), suggesting that selective adenosine A2A receptor antagonists might be useful as adjuncts to L‐DOPA therapy. One of the most important problems in the treatment of PD is to find a drug regimen effective after chronic administration and devoid of dyskinesia‐like side effects. Previous studies have shown that the sensitized turning response, developed in 6‐OHDA‐lesioned rats after chronic intermittent L‐DOPA, is a useful model of dyskinesia. In the present study, we evaluated the effect of a chronic administration of SCH 58261 alone or in combination with L‐DOPA in 6‐OHDA lesioned rats in order to verify the effectiveness of SCH 58261 after repeated administration and its dyskinetic potential. Repeated administration of SCH 58261 (5 mg/kg) did not produce tolerance to its ability to potentiate L‐DOPA‐turning behavior. Moreover, chronic intermittent SCH 58261 (5 mg/kg) plus L‐DOPA produced a stable turning behavior response during the course of the treatment, whereas L‐DOPA alone produced a progressive increase in turning behavior intensity and duration (sensitization). These results suggest that SCH 58261 is effective in potentiating L‐DOPA‐induced turning behavior even after a chronic treatment and it does not produce, in combination with L‐DOPA, motor response alterations. A2A receptor antagonists could be a new and useful tool for the treatment of PD. Drug Dev. Res. 52:387–393, 2001. © 2001 Wiley‐Liss, Inc.
Suppressive effects of adenosine on the 5‐lipoxygenase pathway in human polymorphonuclear leukocytes
Authors: Flamand Nicolas , Plante Hendrick , Picard Serge , Austin Michelle , Surette Marc E. , Krump Éric , Bourgoin Sylvain , Borgeat Pierre 
Published: August 2002

AbstractLeukotrienes are potent mediators of inflammation and host defense. They are also involved in inflammatory and allergic diseases. While numerous studies have investigated the stimulatory mechanisms of leukotriene biosynthesis in phagocytes by inflammatory agents (chemoattractants, cytokines, etc.), the mechanisms responsible for the physiological downregulation of leukotriene biosynthesis have been the subject of very few investigations so far. It has, however, been reported that E‐type prostaglandins are potent inhibitors of leukotriene biosynthesis in chemoattractant‐stimulated neutrophils and we have recently shown with in vitro studies that endogenous adenosine is a potent inhibitor of leukotriene biosynthesis by neutrophils. The present review summarizes our studies demonstrating that adenosine downregulates leukotriene biosynthesis via an interaction with the adenosine A2a receptor on neutrophils; studies aimed at defining the mechanisms of action of adenosine in this process have demonstrated that adenosine inhibits the translocation of the cytosolic enzyme 5‐lipoxygenase to nuclear structures, a process required for leukotriene biosynthesis in neutrophils. Our studies also demonstrated that exposure of human neutrophils to the adenosine A2a receptor agonist CGS‐21680 result in a profound inhibition of the release of arachidonic acid upon cell stimulation. While the previously reported inhibitory effect of adenosine on calcium influx elicited in ligand‐activated neutrophils does not appear to be involved in the inhibitory effects of adenosine on leukotriene biosynthesis, strong evidence supports the implication of elevation of intracellular cyclic AMP concentration both in the inhibition of 5‐lipoxygenase translocation and arachidonic acid release. Drug Dev. Res. 52:397–405, 2001. © 2001 Wiley‐Liss, Inc.
Interplay of constitutively released nucleotides, nucleotide metabolism, and activity of P2Y receptors
Authors: Lazarowski Eduardo R. , Boucher Richard C. , Harden T. Kendall 
Published: August 2002

AbstractAt least six mammalian P2Y receptors exist that are specifically activated by ATP, UTP, ADP or UDP. Although the existence of ectoenzymes that rapidly metabolize extracellular nucleotides is well established, the relative flux of ATP and UTP through their extracellular metabolic products remains undefined. In addition, the existence of basal nucleotide release and the contribution of resting levels of ATP and UTP to P2 receptor activation are poorly understood. In the absence of exogenous agonists, an apyrase‐sensitive inositol phosphate accumulation was observed in resting 16HBE14o– human bronchial epithelial cells endogenously expressing P2Y receptors and in 1321N1 human astrocytoma cells expressing a recombinant P2Y2 receptor. To test whether nucleotide release may account for basal P2 receptor activities, the rates of extracellular accumulation and metabolism of endogenous ATP were examined with resting 16HBE14o–, C6 rat glioma, and 1321N1 cell cultures. Although extracellular ATP concentrations (1‐5 nM) remained unchanged for up to 12 h, [γ32P] ATP included in the medium (as a radiotracer) was completely degraded within 120 min, indicating that ATP release balanced ATP hydrolysis. The calculated basal rates of ATP release ranged from 20 to 200 fmol/min per million cells. HPLC analysis during steady state revealed that the gamma‐phosphate of ATP was reversibly transferred to species further identified as UTP and GTP, implicating ecto‐nucleoside diphosphokinase (NDPK)‐catalyzed phosphorylation of endogenous UDP and GDP. At steady state, the final 32P‐products of [γ32P]ATP metabolism were 32P‐orthophosphoric acid and a species further purified and identified as 32P‐pyrophosphate. Constitutive nucleotide release balanced by the concerted activities of ecto‐ATPase, ecto‐ATP pyrophosphatase, and ecto‐NDPK may determine the resting levels of extracellular nucleotides and therefore, the basal activity of P2 receptors. Drug Dev. Res. 53:66–71, 2001. © 2001 Wiley‐Liss, Inc.
Characteristics of binding sites for ATP4‐ at the human P2X7 receptor
Authors: Klapperstück Manuela , Schmalzing Günther , Markwardt Fritz 
Published: August 2002

AbstractThe effect of the agonist ATP4‐ on whole‐cell currents of Xenopus oocytes expressing the human P2X7 receptor (hP2X7) or a mutant with an incorporated his‐tag and additionally a truncated C‐terminus (his‐hP2X7ΔC) were investigated by means of the two‐microelectrode voltage‐clamp technique. The activation time course of hP2X7 was characterized by an exponential current growth together with a nearly linearly activating current component. HP2X7‐dependent currents deactivated biexponentially with time constants of about 1 and 5 sec after activation by ATP4‐. The amplitude of the exponentially activating current component displays a biphasic dependence on the agonist concentration, which can be best approximated by two Hill functions with Hill coefficients of 2 and dissociation constants of about 4 and 220 μM free ATP4‐ corresponding to two low‐ and two high‐affinity binding sites. The other current components are monophasically dependent on agonist concentration. The linearly activating and the slowly deactivating current components are dependent on the low‐affinity binding sites, whereas for the slowly deactivating current only the high‐affinity binding site is relevant. The effect of the low‐affinity binding sites is abolished in the his‐hP2X7ΔC mutant. It is concluded that hP2X7 receptors possess two types of binding sites with different affinities for ATP4‐ and that the distinct occupation of these sites may lead to different types of activation of the receptor. Drug Dev. Res. 53:77–82, 2001. © 2001 Wiley‐Liss, Inc.
Novel effects of a sleep‐inducing lipid, oleamide, on Ca2+ signaling in renal tubular cells
Authors: Chen Wei‐Chung , Lin Muh‐Chiou , Chou Kang‐Ju , Fang Hua‐Chang , Liu Chun‐Peng , Cheng Jin‐Shiung , Lo Yuk‐Keung , Lee Kim‐Chung , Wang Jue‐Long , Su Warren , Law Yee‐Ping , Jan Chung‐Ren 
Published: August 2002

AbstractThe effect of oleamide, a sleep‐inducing endogenous lipid in animal models, on intracellular free levels of Ca2+ ([Ca2+]i) in Madin‐Darby renal tubular cells was examined using fura‐2 as a fluorescent dye. Oleamide (5–50 μM) increased [Ca2+]i in a concentration‐dependent fashion with an EC50 value of 20 μM. The [Ca2+]i signal comprised an initial rise and an elevated phase and was reduced by removing extracellular Ca2+ by 50%. After pretreatment with 5–50 μM oleamide in Ca2+‐free medium, addition of 3 mM Ca2+ increased [Ca2+]i in a manner dependent on the concentration of oleamide. In Ca2+‐free medium, pretreatment with thapsigargin (1 μM), an endoplasmic reticulum Ca2+ pump inhibitor, abolished [Ca2+]i increases induced by 20 μM oleamide; conversely, pretreatment with 20 μM oleamide reduced 1 μM thapsigargin‐induced [Ca2+]i increases by 50%. Suppression of the activity of phospholipase C with 2 μM U73122 abolished 20 μM oleamide‐induced Ca2+ release. Collectively, these data demonstrate that oleamide induced significant [Ca2+]i increases in renal tubular cells by a phospholipase C‐dependent release of Ca2+ from thapsigargin‐sensitive stores and by inducing Ca2+ entry via store‐operated Ca2+ entry. Drug Dev. Res. 54:40–44, 2001. © 2001 Wiley‐Liss, Inc.
Long‐term retention of spatial navigation by preweanling rats
Authors: Carman Heidi M. , Booze Rosemarie M. , Mactutus Charles F. 
Published: August 2002

AbstractThe present study was designed to examine retention of spatial information in the immature, Fischer‐344N rat using a savings paradigm. Following training to locate a hidden platform using extramaze cues, preweanling animals (17 days of age) were immediately probed by testing in the tank with the platform removed. One week later, pups (26 days of age) were given an additional four training trials immediately followed by a second probe test to examine the animals' memory for the location of the platform. Animals that received initial training at 17 days of age demonstrated significant savings of information when tested after the retention interval. These data replicate our recent report of spatial navigation capabilities in the preweanling rat, and extend those findings by demonstrating that preweanling spatial navigation performance permits more rapid and accurate navigation following a 7‐day retention interval after a “reinstatement” insufficient to produce accurate navigation in maturation controls. © 2002 John Wiley & Sons, Inc. Dev Psychobiol 40: 68–77, 2002
Visual‐preference and operant measures of infant memory
Authors: Wilk Amy E. , Klein Laurie , Rovee‐Collier Carolyn 
Published: August 2002

AbstractIn three experiments with sixty 3‐ and 6‐month‐olds, we examined whether operant and visual‐preference measures of retention are equivalent. Infants learned to move a mobile by kicking and then received a paired‐comparison test with the familiar (training) mobile and a novel one. Kicking above baseline was the direct measure of retention, and longer looking at the novel mobile was the visual‐preference or inferred measure. Retention was tested 1 day after training (Experiment 1) or reactivation (Experiment 2) and immediately or 4 days after training (Experiment 3). Despite differences in age and retention interval, infants consistently exhibited retention on the operant measure, but not on the visual‐preference measure. These data reveal that the two measures of retention are not equivalent. When expectations are associated with a particular stimulus, infants indicate retention directly and robustly, rarely looking longer at a novel test stimulus. This result is not limited to operant situations. © 2001 John Wiley & Sons, Inc. Dev Psychobiol 39: 301–312, 2001
A study on direction‐of‐arrival estimation methods using cosθ amplitude response antenna
Authors: Inaba Takayuki , Takada Jun‐ichi , Araki Kiyomichi , Sakamoto Teijiro , Yanagisawa Hajime 
Published: August 2002

AbstractAt present, when the direction of arrival of a low‐frequency electromagnetic wave such as one in the HF band is measured, loop antennas are used. However, in low‐frequency measurement such as is used in underwater communications, subsurface resource detection, volcanic activity observation, and natural electromagnetic wave observation, the receiving power sensitivity decreases as the frequency is decreased. The purpose of this paper is to use a SQUID (Superconducting QUantum Interference Device), known as an ultrasensitive magnetic sensor, for construction of a small magnetic antenna for estimating the direction of arrival of low‐frequency electromagnetic waves. As a first step, the antenna configuration and direction of arrival estimation method shown below are proposed.
As a low‐frequency broadband antenna with an amplitude response type, we consider a SQUID array, which has a cosθ mode vector consisting of SQUID elements on a circle with a small radius, which is negligible in comparison with the wavelength of the incident wave.
For an antenna with a real‐valued cosθ mode vector, we consider a direction‐of‐arrival estimation method within the framework of the estimation principle of ESPRIT and MUSIC, known as high‐resolution direction‐of‐arrival estimation methods, and derive an estimation method. The obtained estimation method is shown to be ultimately reducible to a simple estimation equation for deriving the phase difference between the −1st and 1st fundamental waves after beam subspace transformation of the correlation function without eigenfunction expansion.
By computer simulation, it is shown that an estimation accuracy of 0.2 to 2° is obtained by this estimation equation for the finitely many elements and snapshots that are actually anticipated. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(10): 8–22, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10009
Evaluation of the normalized impedance of a transverse slot in the image plane of an image NRD guide
Authors: Chirwa Lawrence C. , Morimoto Kenji , Sugawara Yasutaka , Yamamoto Manabu , Omiya Manabu , Itoh Kiyohiko 
Published: August 2002

AbstractA transverse slot placed in the image plane of the image NRD guide that has a low loss nature similar to that of the NRD guide in a millimeter wave circuit can be designed using waveguide array theory. In this paper, a method is presented to derive the normalized impedance of the transverse slot needed for the design from standing wave measurement. Near the slot, the standing wave distribution is disturbed by the field scattered from the slot. A method is given to derive the minimum distance for which no effect of the scattered field is received. From the standing wave distribution in the range where this condition is satisfied, the normalized impedance is evaluated. Further, in order to determine the validity and effectiveness of the evaluation method, an analysis based on the finite difference time domain (FDTD) method is carried out and the results are compared with the experimental data. Finally, a design example of an array antenna is presented. A possibility for applications of the proposed measurement method and the derived normalized impedance to the array antenna design is confirmed. © 2002 Scripta Technica, Electron Comm Jpn Pt 1, 85(5): 25–33, 2002
An adaptive array antenna with SLC‐type preprocessor
Authors: Hirata Kazufumi , Sekiguchi Takashi , Fujisaka Takahiko 
Published: August 2002

AbstractRecently, with rapid proliferation of mobile communication, there has arisen a need for adaptive array antennas that can automatically control the antenna radiation pattern. In adaptive array antennas based on the MMSE (Minimization of Mean Square Error) method, a reference signal with a high correlation with the desired wave is required in order to distinguish the desired wave and the interference waves. The unique word (UW) employed for synchronization in mobile communication is a known signal sequence and can be used as a reference signal. However, it is necessary to accurately estimate the timing at which the UW is contained in the communication signal. The estimation error in the case of strong interference can be a cause of deterioration of the interference suppression capability. Also, if the UW is contained in both the interference and the desired wave at the same timing, the desired wave cannot be recognized and the interference wave cannot be suppressed. In this paper, an adaptive array antenna with a two‐stage configuration using a preprocessing of an SLC (sidelobe canceler) is proposed so that the effect of the interference prior to the start of communication is avoided. By the simulation, it is confirmed that only the interference wave can be suppressed effectively even if the UWs contained in the interference and the desired wave are in synchronization. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(7): 1–11, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1106
An interworking architecture of IN and user CT systems and services
Authors: Yamada Hideaki , Utunomiya Eiji , Masaki Hiroto , Horiuchi Hiroki , Oda Tosikane 
Published: August 2002

AbstractWith progress in intranet/Internet environments and computer telephony (CT) technology, it is expected that intelligent services using IP network will soon be developed. In such services, high‐grade information processing facilities, including terminals, will be actively used, making possible high performance of the user interface and highly sophisticated user‐side processing. This paper proposes a new architecture in which an interworking unit (IW‐Unit) is used in both the user‐side CT system and the net‐side IN system, with examples of added‐value services. The proposed method is a practical high‐grade service for users having CT systems. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(11): 106–114, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1143
Multilayer interconnect technology for scaling
Authors: Kikkawa Takamaro 
Published: August 2002

AbstractWith the miniaturization of silicon ultralarge‐scale integrated circuits (ULSI), the increase in interconnect delay exceeds the delay time of the transistors, and the interconnect begins to control the performance of the entire ULSI chip. To enhance further the speed of ULSI, it is necessary to solve the problem of large‐distance propagation of high‐speed signals in the large‐scale chip. The damascene multilayer interconnect integration technology is an important interconnect technology for achieving large‐scale integration and high speed in ULSI at low cost. CMP technology, Cu electroplating technology, and low‐dielectric‐constant insulating film layers are described as element process technologies required for its implementation. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(4): 26–40, 2001
Influence of electrical source impedance on phase shift of sound wave in the ultrasonic velocity measurement
Authors: Sasaki Daizo , Imano Kazuhiko , Inoue Hiroshi 
Published: August 2002

AbstractIn acoustic velocity measurement using ultrasonic waves, the composite resonator method with the sample and the transducer becomes a source of error. This phenomenon is considered as a phase shift at the boundary between the transducer and the sample and is analyzed by numerical simulation. From the result, it is found that the phase shift depends on the electrical source impedance and that the phase shift can be minimized by setting the electrical source impedance equal to the reactance of the transducer at resonance, depending on the acoustic condition of the backing of the transducer. The results of experiments with a varying electrical source impedance are found to be similar to those of simulations. Further, it becomes possible to measure the acoustic velocity of water with a discrepancy of less than 0.1% from the referenced value if the phase shift is eliminated by taking the propagation time difference in two samples with different lengths. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(4): 41–48, 2001
Detection performance of coherent signals by the polarization averaging MUSIC algorithm
Authors: Yamada Hiroyoshi , Yamakura Toshiharu , Yamaguchi Yoshio 
Published: August 2002

AbstractIn remote sensing and the evaluation of radio wave propagation, there has recently been interest in highly accurate estimation methods with high resolution, including polarization information. In the superresolution method, which realizes a high resolution that cannot be achieved by the Fourier transform method, several reports have been presented on the use of polarization information. This paper considers polarization‐averaging correlation reduction preprocessing, which is one of the methods of utilizing polarization data in the superresolution method. The correlation reduction performance when combined with SSP and MSSP is examined from theoretical and quantitative standpoints. It is shown by computer simulation that the MSSP method combined with polarization averaging can effectively reduce correlation by utilizing polarization, and that it achieves a higher estimation accuracy than other methods in propagation estimation with a smaller number of snapshots. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(7): 1–9, 2001
The effect of surface oxidation status on 0.35‐μm HIGFET characteristics
Authors: Ohshika Katsushi , Kuroda Jun , Yanazawa Hiroshi 
Published: August 2002

AbstractThe paper discusses the effect of the oxide film formed on the surface of GaAs substrate of the gate metal of 0.35‐μm WSi gate HIGFET (Heterostructure Insulated Gate FET) on its characteristics. An optimized SiON film (refractive index 1.58) deposited by plasma CVD method onto the entire HIGFET surface was used as a passivation film to protect the gate metal substrate [1]. In order to modify oxidation conditions on the GaAs surface, two oxidation methods were utilized: low‐temperature oxidation (further referred to as UV/O3 oxidation), which utilizes O3 generated from the atmospheric O2 by applying ultraviolet irradiation produced by a mercury lamp (184.9 and 253.7 nm), and high‐temperature thermal oxidation performed at 400 °C in air. Based on the results of spectroscopic ellipsometry, Auger spectrometry, and XPS analyses, it was the UV/O3 method that led to formation of thermally unstable SiON/GaAs oxide film on the GaAs interface layer due to higher concentration of As oxide. During the heat treatment, involved in the FET fabrication process, As oxide would react with SiON resulting in its thermal decomposition and formation of free As. On the other hand, the oxide film formed during thermal oxidation at 400 °C led to formation of more thermally stable SiON/GaAs oxide film/GaAs interface layer due to higher concentration of Ga oxide via decomposition of thermally unstable As oxide during the heating process. In either case, the presence of GaAs oxide film along with free As in the SiON passivation film deposited onto GaAs substrate is believed to be a major reason for declining FET characteristics. This suggests that removal of the oxide film from the surface prior to depositing a passivation film is required. The improved stability of the FET characteristics was achieved by removing the GaAs oxide film using wet etching with BHF during the FET fabrication process. © 2001 Scripta Technica, Electron Comm Jpn Pt 2, 84(7): 46–57, 2001