bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ascorbate‐induced differentiation of embryonic cortical precursors into neurons and astrocytes
Authors: Lee Ji‐Yeon , Chang Mi‐Yoon , Park Chang‐Hwan , Kim Hye‐Young , Kim Jin‐Hyuk , Son Hyeon , Lee Yong‐Sung , Lee Sang‐Hun 
Published: October 2004

AbstractA specific role for ascorbate (AA) in brain development has been postulated based on a rise of AA levels in fetal brain (Kratzing et al., 1985). To evaluate the role of AA during CNS development, we analyzed the survival, proliferation, and differentiation of AA‐treated CNS precursor cells isolated from rat embryonic cortex. Immunocytochemical analyses revealed that AA promoted the in vitro differentiation of CNS precursor cells into neurons and astrocytes in a cell density‐dependent manner. Additionally, AA increased the frequency and amplitude of miniature excitatory postsynaptic currents (mEPSCs) of postmitotic neurons in primary neuronal cultures. Differential expression analysis of genes specific to neuronal or glial differentiation revealed an AA‐dependent increase in the expression of genes that could potentially compound the effects of AA on cell differentiation. These data suggest that AA may act in the developing brain to stimulate the generation of CNS neurons and glia, thereby assisting in the formation of neural circuits by promoting the acquisition of neuronal synaptic functions. © 2003 Wiley‐Liss, Inc.
Cholinergic modulation of neurofilament expression and neurite outgrowth in chick sensory neurons
Authors: Tata Ada Maria , Cursi Silvia , Biagioni Stefano , Augusti‐Tocco Gabriella 
Published: October 2004

AbstractThe morphogenetic role of the neurotransmitter acetylcholine was studied in cultures of dorsal root ganglia (DRG) neurons obtained from E12 and E18 chick embryos. With this model we have evaluated neurofilament expression and neurite outgrowth following cholinergic agonist and antagonist treatment. Morphometric analysis undertaken to evaluate fiber outgrowth has indicated that E12 DRG cultures treated with cholinergic agonists, such as muscarine and carbachol, when compared with untreated cultures, have longer fibers and a higher number of fibers per neuron. Concomitant treatment with agonists and the antagonists atropine or mecamylamine counteracts the increase in fiber outgrowth, suggesting that the cholinergic agonist effects were mediated by both muscarinic and nicotinic receptors. The expression of the three neurofilament proteins was also evaluated. Western blot analysis showed that, in E12 DRG cultures, both muscarine and carbachol induce a significant increase in neurofilament protein expression and that this effect is inhibited by cholinergic antagonist treatment. Moreover, Northern blot analysis has demonstrated that the increased expression of 68‐ and 145‐kDa neurofilament proteins is dependent on cholinergic modulation of the neurofilament transcripts. Modulated expression of neurofilament proteins by cholinergic agonists was not evident in E18 DRG cultures, suggesting that, when sensory neurons have completed their differentiation, the cholinergic system might be involved in other functions. In conclusion, our data demonstrate that, during sensory neuron development, acetylcholine modulates neurite outgrowth controlling neurospecific marker expression. © 2003 Wiley‐Liss, Inc.
Mechanism of interleukin‐1β‐induced calcitonin gene‐related peptide production from dorsal root ganglion neurons of neonatal rats
Authors: Hou Lingfei , Li Wenjing , Wang Xian 
Published: October 2004

AbstractCalcitonin gene‐related peptide (CGRP) is synthesized in dorsal root ganglion (DRG) neurons and released from primary afferent neurons to mediate hemodynamic effects and neurogenic inflammation. The effect of the proinflammatory cytokine interleukin‐1 (IL‐1)‐β on CGRP release from these sensory neurons was investigated. The results showed that IL‐1β (1 ng/ml) could directly induce CGRP release following prolonged incubation (24 hr) with these neurons. Treatment with IL‐1β (0.1–1.0 ng/ml) significantly increased CGRP release in a concentration‐dependent manner. In addition, pretreatment of DRG cells with actinomycin D at 1 μM or cyclohexamide at 10 μM for 30 min inhibited 1 ng/ml IL‐1β‐induced CGRP release in DRG neurons of neonatal rats. The inhibitors of PKC, JNK MAPK and NF‐κB, but not p38 or ERK1/2 MAPK, blocked IL‐1β‐induced CGRP release. RNase protection assay showed that IL‐1β could cause α‐CGRP mRNA increase in a time‐ and concentration‐dependent manner, although the level of β‐CGRP mRNA was not affected. These results indicate that IL‐1β may activate PKC, which in turn initiates JNK MAPK and activates NF‐κB and finally induces α‐CGRP gene expression and release from these sensory neurons. © 2003 Wiley‐Liss, Inc.
Intracerebroventricular administration of GABA‐A and GABA‐B receptor antagonists attenuate feeding and sleeping‐like behavior induced by L‐pipecolic acid in neonatal chicks
Authors: Takagi T. , Bungo T. , Tachibana T. , Saito E‐S. , Saito S. , Yamasaki I. , Tomonaga S. , Denbow D.M. , Furuse M. 
Published: October 2004

AbstractIt has been demonstrated that L‐pipecolic acid (L‐PA), a major metabolic intermediate of L‐lysine (L‐Lys) in the mammalian and chicken brain, is involved in the functioning of the GABAergic system. A previous study has shown that intracerebroventricular (i.c.v.) injection of L‐PA suppressed feeding and induced sleep‐like behavior in neonatal chicks; however, the precise relationship between the GABAergic system and L‐PA has not been clarified. In the present study, the role of the GABA‐A or GABA‐B receptors in the suppression of food intake and induction of sleeping‐like behavior by L‐PA was investigated. Chicks were injected i.c.v. with the GABA‐A antagonist picrotoxin or GABA‐B antagonist CGP54626 along with L‐PA. Although suppression of food intake by L‐PA was restored partially by co‐injection with CGP54626, but not picrotoxin, sleep‐like behavior induced by L‐PA was suppressed significantly by both antagonists. These results suggested that L‐PA activated both GABA‐A and GABA‐B receptors, and GABA‐B receptors alone contributed to food intake whereas both receptors contributed to sleep‐like behavior. © 2003 Wiley‐Liss, Inc.
Raman spectroscopy of gerhardtite at 298 and 77 K
Authors: Frost Ray L. , Leverett Peter , Williams Peter A. , Weier Matt L. , Erickson Kristy L. 
Published: October 2004

AbstractRaman spectroscopy has been used to study the nature of gerhardtite, a naturally occurring basic copper(II) nitrate of formula Cu2NO3(OH)3. Raman spectra at 77 K show four bands at 3557, 3548, 3467 and 3409 cm−1 in accordance with the crystal structure with three non‐equivalent hydroxyl groups. Estimations of hydrogen bond distances of 0.3019, 0.2987, 0.2855 and 0.2804 pm are obtained. Cooling to liquid nitrogen temperatures did not affect these values. Two bands are observed at 1048 and 1052 cm−1 in the NO3 stretching region. Cooling to liquid nitrogen temperature altered the ratio of these nitrates from 3/1 to 1/3. Two sets of bands in the antisymmetric stretching region of the nitrate in the 77 K spectra suggest that there are two non‐equivalent nitrate anions in the gerhardtite structure at liquid nitrogen temperature. X‐ray crystallography suggests three independent oxygens in the one nitrate group. The shift in band positions on obtaining Raman spectra at 298 at 77 K indicates a phase change is occurring for the mineral upon cooling to 77 K. Copyright © 2004 John Wiley & Sons, Ltd.
Kinetic Studies of Liquid Crystalline and Isotropic Vinyl Ester Resins
Authors: Frigione Mariaenrica , Calò Emanuela , Maffezzoli Alfonso , Carfagna Cosimo , Malucelli Giulio 
Published: October 2004

AbstractSummary: The curing process of a commercial vinyl ester (VE) resin was characterized by calorimetric and spectroscopic techniques. A phenomenological kinetic model, experienced in previous studies, was employed to describe the proceeding of curing reactions. The model is able to describe the behavior of the processing variables, i.e. rate and degree of the reaction, during the curing of the resin under different conditions (heating rates). The effect of diffusion control phenomena on the reaction kinetics, associated with the evolution of the glass transition temperature as a function of the degree of polymerization and cross‐linking, was taken into account in the formulation of the kinetic model. A simpler model was proposed and verified for a liquid crystalline vinyl ester resin, synthesized by the authors. The model, in particular, did not take into account the effects of vitrification. The kinetic parameters were again evaluated by processing the calorimetric data. The kinetic study of the liquid crystalline monomer is performed after isotropization and therefore, the acceleration effect, associated with the cure in liquid crystalline phase is not taken into account for the kinetic analysis. Also in this case, the comparison between theoretical and experimental data was very satisfying.Experimental (full line) and predicted data (dotted line) of degree of reaction vs. time for the vinyl ester resin.magnified imageExperimental (full line) and predicted data (dotted line) of degree of reaction vs. time for the vinyl ester resin.
Atom Transfer Radical Polymerization of Glycidyl Methacrylate: A Functional Monomer
Authors: Cañamero Pedro Francisco , de la Fuente José Luis , Madruga Enrique López , Fernández‐García Marta 
Published: October 2004

AbstractSummary: A detailed investigation of the polymerization of glycidyl methacrylate (GMA), an epoxy‐functional monomer, by atom transfer radical polymerization (ATRP) was performed. Homopolymers were prepared at relatively low temperatures using ethyl 2‐bromoisobutyrate (EBrIB) as the initiator and copper halide (CuX) with N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA) as the catalyst system. The high polymerization rate in the bulk did not permit polymerization control. However, homopolymerization in solution enabled us to explore the effects of different experimental parameters, such as temperature, solvent (toluene vs. diphenyl ether) and initiator concentration, on the controllability of the ATRP process. SEC analysis of the homopolymers synthesized confirmed the importance of solvent character on molecular weight control, the lowest polydispersity indices ($\overline M _{\rm w} /\overline M _{\rm n} < 1.25$) and the highest efficiencies being found when the polymerizations were performed in diphenyl ether in combination with a mixed halide technique. A novel poly(glycidyl methacrylate)‐block‐poly(butyl acrylate) (PGMA‐b‐PBA) diblock copolymer was prepared through ATRP using PGMA‐Cl as a macro‐initiator. This chain growth experiment demonstrated a good living character under the conditions employed, while simultaneously indicating a facile synthetic route for this type of functional block copolymer. In addition, the isotacticity parameter for the PGMAs obtained was estimated using 1H NMR analysis which gave a value of σGMA = 0.26 in agreement with that estimated in conventional radical polymerization.SEC chromatograms of PGMA‐Cl macroinitiator and PGMA‐b‐PBA diblock copolymer.magnified imageSEC chromatograms of PGMA‐Cl macroinitiator and PGMA‐b‐PBA diblock copolymer.
Fabrication and Characterization of GRIN Plastic Rods Containing Silver Nanoparticles with Novel Surfmers
Authors: Liu Jui‐Hsiang , Wu Dung‐Shin , Tseng Kuei‐Yu 
Published: October 2004

AbstractSummary: Both novel polymerizable surfactants of 2‐(methacroyloxy)ethyl succinate (MAES) and succinic acid mono{11‐[2‐(2‐methylacryloyloxy)ethoxy]undecyl} ester (SAME‐11) were synthesized in this investigation. A novel method was also developed for the preparation of gradient refractive index (GRIN) plastic rods containing inorganic nanoparticles with the polymerizable surfactants (surfmers). Silver nanoparticles were prepared using W/O (water in oil) reverse micelle technique in the presence of the surfmers. The effect of w values (w = [H2O]/[surfmer]), silver nitrate concentration, surfmer/isooctane/H2O ratio, and initiator concentration on the nanoparticle size was investigated. The optical absorption spectra of the micellar samples were recorded on a spectrophotometer at room temperature in the range of 200–900 nm. The nanoparticle size was confirmed with a transmission electron microcopy (TEM) technique. To introduce the nanoparticles into the GRIN plastic rods, methyl methacrylate (MMA) was used instead of isooctane in the organic phase. Nanoparticles were found to increase the refractive index of plastic rods effectively. Light scattering and an opaque appearance due to the aggregation of nanoparticles and the existence of surfactants were solved using the polymerizable surfmers in this investigation. We estimated both the real image transmission and the three dimensional refractive index distributions of the prepared GRIN plastic rods. The results of this investigation suggested that nanoparticles could be used as a kind of dopant to fabricate GRIN plastic rods and increased its refractive index effectively. Polymerizable surfactant could further raise the refractive index of the core of the GRIN rods leading to an increase of the numerical apertures (NA) and the acceptance angle (θmax) of the plastic rods.Three dimensional refractive index distribution of GRIN plastic rod prepared in this investigation.magnified imageThree dimensional refractive index distribution of GRIN plastic rod prepared in this investigation.
Poly(acrylamide‐co‐itaconic acid) and Semi‐IPNS with Poly(ethylene glycol): Preparation and Characterization
Authors: Kalagasidis Krušić Melina , Danković Danijel , Nikolić Marija , Filipović Jovanka 
Published: October 2004

AbstractSummary: A pH‐responsive poly(acrylamide‐co‐itaconic acid) (PAAm/IA) hydrogel and semi‐interpenetrating networks (semi‐IPNs) with 5, 10 and 15 wt.‐% of poly(ethylene glycol) (PAAm/IA/PEG), were synthesized. Their swelling behavior was studied in the pH range from 1.76 to 7.81, as well as their oscillatory swelling behavior at pH = 7.81 and pH = 1.7. Throughout these studies, the gels maintained their mechanical strengths and shape. The shear storage (G′) and loss (G″) moduli, obtained as a function of frequency, for the gels as formed and at equilibrium swelling were higher for the semi‐IPNs than for the copolymer hydrogel. The shear storage moduli of copolymer hydrogel and semi‐IPNs as formed were independent of frequency over the whole experimental range, whereas the values for the gels at equilibrium swelling decreased with increasing degree of swelling, i.e., the PAAm/IA hydrogel which exhibited the largest swelling had the lowest G′ value. The G′ and G″ values also depended on the content of PEG.Diffusion exponent vs. pH for PAAm, copolymer hydrogel PAAm/IA and semi‐IPN with PEG.magnified imageDiffusion exponent vs. pH for PAAm, copolymer hydrogel PAAm/IA and semi‐IPN with PEG.
Intraoperative magnification: Who uses it?
Authors: Jarrett Paul Max 
Published: October 2004

AbstractSurgeons over recent decades have made increasing use of intraoperative magnification to enhance the outcome of surgical procedures, yet no published information exists regarding the extent of magnification use within surgical specialties. A sample of surgeons consisting of 148 specialists and senior surgical trainees in the west of Scotland was surveyed by postal questionnaire regarding their frequency and types of magnification use. Patterns of use were similar within each specialty, but varied markedly between specialties. Otolaryngologists and plastic, maxillofacial, and ophthalmic surgeons use both loupes and microscopes frequently. Cardiothoracic and pediatric surgeons tend only to utilize loupes, whereas neurosurgeons tend only to use microscopes. General surgeons, urologists, orthopedic surgeons, and gynecologists are infrequent users or nonusers of magnification, and when required will utilize loupes rather than microscopes. As a clear pattern of magnification use exists, it should be possible to anticipate the equipment needs of surgeons when providing theater services. © 2004 Wiley‐Liss, Inc. Microsurgery 24:420–422, 2004.
176–200‐GHz receiver module using indium phosphide and gallium arsenide MMICs
Authors: Archer John W. , Shen Mei Gan 
Published: October 2004

AbstractThis paper describes an integrated circuit‐based, down‐converting receiver module operating in the 176–200‐GHz range. The multichip module incorporates a cascaded pair of indium phosphide (InP) monolithic microwave integrated circuit (MMIC) amplifiers, providing a combined gain of more than 30 dB over the 176–200‐GHz band. The output from the amplifiers is fed to a subharmonically pumped InP passive‐HEMT block down‐converter that provides an IF output in the 0.5–15‐GHz range with a local oscillator (LO) signal between 46 and 50 GHz. A gallium arsenide (GaAs) medium‐power amplifier provides the LO drive for the mixer. For RF frequencies in the 176–185‐GHz band, the receiver exhibits a typical CW down‐conversion gain between 0 and 3 dB and a typical noise figure of 9 dB when operating at room temperature. For RF frequencies in the 190–196‐GHz band, the receiver exhibits a typical CW down‐conversion gain between 2 and 5 dB and a typical noise figure of 11 dB. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 458–462, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20501
Compact directive antennas with a wire‐medium artificial lens
Authors: Ikonen Pekka , Simovski Constantin , Tretyakov Sergei 
Published: October 2004

AbstractIn this paper, we present the results of numerical and experimental investigations of a prospective antenna which can be used, for example, as a base‐station antenna in cellular telecommunication systems. The antenna is a half‐wavelength dipole surrounded by periodically arranged capacitively loaded wires. Its operation is based on the recently suggested principle of the wire‐medium artificial lens. The development of this concept can possibly lead to the design of compact (0.2–0.5 wavelength in diameter) electrically controllable base‐station antennas. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 467–469, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20503
Design of a new X‐band active resonator oscillator
Authors: Lee Yeon‐Joo , Yun Tae‐Soon , Kim Ki‐Byoung , Lee Jong‐Chul 
Published: October 2004

AbstractIn this paper, a microstrip active resonator oscillator (ARO) for X‐band application is presented. The ARO is implemented on Teflon substrate with relative dielectric constant of 2.52, height of 0.54 mm, and metal thickness of 0.017 mm. The ARO shows 6‐dBm output power at 10 GHz, 2nd‐harmonic suppression of −20.1 dBc, phase noises of −57.27 and −92 dBc/Hz at the offset frequencies of 1 and 100 kHz, respectively, and a frequency tuning range of 43.7 MHz with 0.05% output error. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 472–475, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20505
Generation of 40‐GHz pulse trains from a 5‐GHz dual‐driving rational harmonic mode‐locked semiconductor fiber‐ring laser
Authors: Jong Kim Yun , Ghiu Lee Chung , Jo Hyun‐Jeong , Park Chang‐Soo 
Published: October 2004

AbstractWe present and demonstrate a simple method of generating 40‐GHz repetition‐rate pulse trains from a rational harmonic mode‐locked semiconductor fiber‐ring laser with 5‐GHz dual‐driving signal by using pulse‐amplitude equalization. By adjusting the voltages applied to both arms of the modulator pulse trains with an eight‐times repetition rate are equalized in their amplitudes. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 489–491, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20511
Lens or resonator? Electromagnetic behavior of an extended hemielliptic lens for a sub‐millimeter‐wave receiver
Authors: Boriskin Artem V. , Nosich Alexander I. , Boriskina Svetlana V. , Benson Trevor M. , Sewell Phillip , Altintas Ayhan 
Published: October 2004

AbstractThe behavior of a 2D model of an extended hemielliptic silicon lens of a size typical for THz applications is accurately studied for the case of a plane E‐wave illumination. The full‐wave analysis of the scattering problem is based on the Muller's boundary integral‐equations (MBIE) that are uniquely solvable. A Galerkin discretization scheme with a trigonometric basis leads to a very efficient numerical algorithm. The numerical results related to the focusability of the lens versus its rear‐side extension and the angle of the plane‐wave incidence, as well as near‐field profiles, demonstrate strong resonances. Such effects can change the principles of optimal design of lens‐based receivers. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 515–518, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20520
Development of ground‐penetrating image radar using a novel compact ultra‐wideband monopole antenna
Authors: Kim Kwan‐Ho , Park Young‐Jin , Park Han‐Kyu 
Published: October 2004

AbstractA compact ultra‐wideband ground‐penetrating radar (UWB GPR) using an impulse waveform is developed. A proper impulse generator is designed and then a novel compact UWB monopole antenna is developed for transmitting the impulse and receiving the reflected signals. For visualization of buried targets, image processing is performed. For verification, a UWB GPR prototype is built. The experimental results show that the system has very good depth and spatial resolution. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 521–524, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20522
A large dynamic‐range self‐adjusting output‐power laser device
Authors: Lu Z. G. , Grover C. P. 
Published: October 2004

AbstractWe investigate a stable semiconductor fiber‐ring laser (SFRL) whose output power can be controlled by external light injection. Based on this SFRL, we develop a novel laser for keeping its output power approximately constant when the input power is changed over a dynamic range of 17 dB. Potential applications are discussed. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 532–535, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20525
Finite‐ground‐plane effects on the ultra‐wideband planar monopole antenna
Authors: Su Saou‐Wen , Wong Kin‐Lu , Cheng Yuan‐Tung , Chen Wen‐Shyang 
Published: October 2004

AbstractImpedance and radiation characteristics of an ultra‐wideband (UWB) planar monopole antenna with a finite circular ground plane are experimentally studied. The significant effects of the ground‐plane size on the lower‐edge frequency of the antenna's impedance bandwidth are observed, and there exists an optimal diameter of the circular ground plane for achieving a maximum impedance bandwidth. Large ground‐plane effects on the radiation pattern and antenna gain are also seen, especially for the lower frequencies in the antenna's UWB impedance bandwidth. Details of the experimental results are presented and discussed. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 535–537, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20526
NMR assignments and single‐crystal X‐ray diffraction analysis of deoxyloganic acid
Authors: Teng Rong Wei , Wang De Zu , Wu Yun Shan , Lu Yang , Zheng Qi Tai , Yang Chong Ren 
Published: October 2004

Abstract7‐Deoxyloganic acid (1), citrusin C (2), 3,4‐dihydroxyl benzoic acid (3) and (E)‐caffeic acid (4) were isolated from the water‐soluble fraction of ethanol extracts of Morina nepalensis var. alba Hand.‐Mazz. and their structures were determined on the basis of spectroscopic evidence. The total assignments of 1H and 13C NMR spectra of 1 in solvents CD3OD, D2O and CDCl3 were reported, in addition to the single‐crystal X‐ray diffraction analysis of its tetraacetate 1a. All compounds were obtained from Morina genus for the first time. Copyright © 2004 John Wiley & Sons, Ltd.