bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of serum‐free medium on the expression of glutamate transporters and the susceptibility to glutamate toxicity in cultured cortical neurons
Authors: Velasco Iván , Velasco‐Velázquez Marco A. , Salazar Patricia , Lajud Naima , Tapia Ricardo
Published: March 2003

The presence of glia and glial glutamate transporters seems to modify glutamate‐mediated toxicity in neuronal cultures. In this work we cultured cortical cells in serum‐containing medium and in a serum‐free medium (Neurobasal medium + B27 supplement) and studied the expression of the glutamate transporters GLAST, GLT, and EAAC by immunocytochemistry and RT‐PCR. The proportion of glial cells was below 10% in the Neurobasal medium and 46% in the serum‐containing medium. Semiquantitative evaluation of the mRNA for the glutamate transporters showed similar amounts in cells grown in serum‐free and serum‐containing media. We detected immunoreactivity for the three transporters in both media, but EAAC was coexpressed with the neuronal marker MAP2, whereas GLAST and GLT predominated in nonneuronal cells. When the cultures were treated with glutamate for 15 min, the cultures in serum‐containing medium showed a clear concentration‐dependent neuronal death, whereas cells primed in this medium and switched to Neurobasal medium, as well as cells grown only in the latter, were less sensitive to glutamate concentrations up to 1 mM. A similar difference in the sensitivity to excitotoxicity was observed when the glutamate uptake inhibitor L‐trans‐2,4‐pyrrolidine‐dicarboxylate was applied during 6 hr, although the accumulation of extracellular glutamate was similar in the two media. We conclude that glutamate transporters with the culture conditions studied are sensitive to glutamate uptake inhibition and that Neurobasal/B27 medium protects cells against excitotoxicity. © 2003 Wiley‐Liss, Inc.
Genes regulated by learning in the hippocampus
Authors: Leil Tarek A. , Ossadtchi Alex , Nichols Thomas E. , Leahy Richard M. , Smith Desmond J.
Published: March 2003

The enduring changes in long‐term memory probably depend on regulation of gene expression in the hippocampus. To seek genes regulated by learning, we used microarray technology to compare hippocampal gene expression in mice undergoing training in the Morris water maze and control mice forced to swim for the same period in the absence of a hidden platform. ANOVA was employed to prioritize genes for further study, and three genes were confirmed by real‐time PCR as being regulated during learning. One of the genes was the α subunit of the platelet‐derived growth factor receptor (Pdgfra); another showed homology to DnaJ and cAMP response element‐binding protein 2 (CREB2); and a third was novel. These genes may provide useful insights into the molecular mechanisms of hippocampal learning. © 2003 Wiley‐Liss, Inc.
BDNF‐induced survival of auditory neurons in vivo: Cessation of treatment leads to accelerated loss of survival effects
Authors: Gillespie Lisa N. , Clark Graeme M. , Bartlett Perry F. , Marzella Phillip L.
Published: March 2003

Neurotrophic factors are important for the development and maintenance of the auditory system. They have also been shown to act as survival factors for auditory neurons in animal deafness models. Studies have demonstrated recently that these neurotrophic factors not only maintain survival of auditory neurons, but that these surviving neurons retain functionality. It remains to be determined, however, if a single administration of a neurotrophic factor is sufficient to maintain auditory neuron survival after loss of hair cells, or if sustained delivery is required. This study investigated the longevity of the survival effects of BDNF on auditory neurons in deafened guinea pigs. Briefly, the left cochleae of deafened guinea pigs were infused with BDNF for 28 days via a mini‐osmotic pump, and neuronal survival was analyzed at various stages after the completion of treatment. BDNF treatment prevented the degeneration of auditory neurons that normally is seen after a loss of hair cells, supporting previous studies. Our results indicate, however, that cessation of BDNF treatment leads to an accelerated decline in auditory neuron survival as compared to that observed in deafened, untreated cochleae. These findings indicate that much work remains to be done to establish a technique for the long‐term survival of auditory neurons in the deaf ear. © 2003 Wiley‐Liss, Inc.
Holocene molluscan faunal history and environmental change at Kloster Mühle, Rheinland‐Pfalz, western Germany
Authors: Meyrick R. A.
Published: March 2003

The Holocene molluscan succession presented here, from a tufa at Kloster Mühle, near Trier, is the most detailed yet published from the German Bundesland of Rheinland‐Pfalz. The base of the sequence, dated at 9720 ± 7514C yr BP, indicates that the early Holocene was characterised by a moist, open‐ground fauna dominated bySuccinea/Oxyloma. The aquatic phase that follows is short lived, bracketed by statistically indistinguishable dates of 9530 ± 6014C yr BP (below) and 9695 ± 7514C yr BP (above). The establishment of woodland is indicated by the appearance ofAegopinella nitidula,Vertigo pusillaand especiallyCarychium tridentatum, which subsequently expands to account for over 40% of the total fauna. Deciduous forest optimum conditions, characterised by the occurrence ofPlatyla politaandHelicigona lapicida, become established at about 7405 ± 5014C yr BP. The radiocarbon age of 4384 ± 10514C yr BP obtained for the uppermost tufa horizon is much younger than expected, both on the basis of the molluscan fauna observed and the implied decline in the rate of sedimentation in the upper part of the deposit, and tufa formation probably ceased much earlier than this date suggests. Copyright © 2002 John Wiley & Sons, Ltd.
River sediments, great floods and centennial‐scale Holocene climate change
Authors: Macklin Mark G. , Lewin John
Published: March 2003

A new analysis of all 346 published 14C dated Holocene alluvial units in Britain offers a unique insight into the regional impacts of global change and shows how surprisingly sensitive British rivers have been to relatively modest but repeated changes in climate. Fourteen major but probably brief periods of flooding are identified bracketed within the periods 400–1070, 1940–3940, 7520–8100 and at ca. 10 420 cal. yr BP. There is a strong correspondence between climatic deteriorations inferred from mire wet shifts and major periods of flooding, especially at ca. 8000 cal. yr BP and since ca. 4000 cal. yr BP. The unusually long and complete British record also demonstrates that alterations in land cover have resulted in a step change in river basin sensitivity to variations in climate. This has very important implications for assessing and mitigating the impact of increasing severe flooding. In small and medium‐sized river basins land use is likely to play a key role in either moderating or amplifying the climatic signal. Copyright © 2003 John Wiley & Sons, Ltd.
Relict mountain slope deposits of northern Portugal: facies, sedimentogenesis and environmental implications
Authors: Texier Jean‐Pierre , Meireles José
Published: March 2003

This paper deals with the formation processes and the palaeoenvironmental significance of relict slope deposits located on the uppermost part of the north Portugal mountains. For this purpose, seven key sites representative of the different lithofacies have been selected and analysed in detail. The data show that three main dynamic processes are responsible for the emplacement of regional fossil slope deposits: runoff, debris flows and dry grain flows. The ubiquity of these processes and the lack of frost‐related features or landforms do not support the existence of severe Pleistocene climates in this part of the lberian Peninsula as postulated by previous work. Pedological data gathered at one of the study sites show that a subalpine environment was probably present at 700–800 m altitude between 29 and 14 kyr. Using data from the Pyrenees Mountains, a 6.5 to 12°C depression in mean annual temperature has been tentatively postulated for this Pleniglacial period. Copyright © 2003 John Wiley & Sons, Ltd.
Adsorption of lucigenin on Ag nanoparticles studied by surface‐enhanced Raman spectroscopy: effect of different anions on the intensification of Raman spectra
Authors: Millán Juan I. , Garcia‐Ramos José V. , Sanchez‐Cortes Santiago , Rodríguez‐Amaro Rafael
Published: March 2003

The normal Raman and surface‐enhanced Raman spectra of acridine derivative lucigenin were analysed on Ag colloid. The effect of different anions on the adsorption mechanism of this molecule was also investigated under different experimental conditions, i.e. excitation wavelength and adsorbate concentration, in order to study the different adsorption of the molecule on the metal under different conditions. The adsorption of lucigenin, which is under the dicationic form, changes depending on the anion added to the surface: in the presence of chloride the molecule forms an ion pair, with a predominant perpendicular orientation, whereas in the presence of sulphate and nitrate, the adsorption is weak and the dication seems to adopt a different orientation with respect to the surface. Copyright © 2003 John Wiley & Sons, Ltd.
Vibrational spectra and force field calculation of A2Mn2O7 (A = Y, Dy, Er, Yb) pyrochlores
Authors: Brown Sonal , Gupta H. C. , Alonso J. A. , Martinez‐Lope M. J.
Published: March 2003

Raman and infrared spectra were recorded for A2Mn2O7 (A = Y, Dy, Er, Yb) pyrochlores. For the first time, lattice dynamic analysis of cubic manganate pyrochlores was carried out using a short‐range force model with four stretching and four bending force constants at the zone center. The assignment of all their modes is proposed. The calculated force constants are discussed and compared for the different pyrochlores. The evaluated wavenumbers are close to the available observed infrared and Raman wavenumbers, giving further support to the present assignments. Copyright © 2003 John Wiley & Sons, Ltd.
Sensitization of thermotolerant SCK cells to hyperthermia and freezing with reduction of intracellular pH: Implications for cryosurgery
Authors: Burgher Abram H. , Swanlund David J. , Griffin Robert J. , Song Chang W. , Bischof John C. , Roberts Kenneth P.
Published: March 2003

Background and Objectives

During cryosurgery, cells frozen slowly at the outer part of the ice ball undergo severe dehydration and are subject to solute effects injury, which may be caused in part by protein denaturation. This study was undertaken to determine whether heat shock proteins (HSPs), the molecular chaperones that stabilize proteins against denaturation, have a protective effect on cells during slow freezing. In addition, we aimed to determine whether acidic conditions, similar to those found in many solid tumors, would effect this protection.

Methods

SCK cells were frozen at 5°C/min to −10°C or −20°C before or after induction of thermotolerance, and at neutral or low pH conditions. Lethal damage was determined by clonogenics.

Results

Clonogenic survival was decreased by 50% in thermotolerant cells frozen to −10°C after culture in acidic conditions (pH 6.6) compared with non‐thermotolerant cells cultured at neutral pH. Induction of thermotolerance alone or low pH alone did not significantly sensitize SCK cells to freezing. All treatment groups were equally susceptible to killing when frozen to −20°C.

Conclusions

Our results show that induction of thermal tolerance does not protect SCK cells against subsequent freezing injury and that a low pH environment actually sensitizes these cells to freeze injury. J. Surg. Oncol. 2003;82:160–169. © 2003 Wiley‐Liss, Inc.
Efficacy of low power laser therapy and exercise on pain and functions in chronic low back pain
Authors: Gur Ali , Karakoc Mehmet , Cevik Remzi , Nas Kemal , Sarac Aysegul Jale , Karakoc Meral
Published: March 2003

Background and Objectives

The aim of this study was to determine whether low power laser therapy (Gallium–Arsenide) is useful or not for the therapy of chronic low back pain (LBP).

Study Design/Materials and Methods

This study included 75 patients (laser + exercise—25, laser alone—25, and exercise alone—25) with LBP. Visual analogue scale (VAS), Schober test, flexion and lateral flexion measures, Roland Disability Questionnaire (RDQ) and Modified Oswestry Disability Questionnaire (MODQ) were used in the clinical and functional evaluations pre and post therapeutically. A physician, who was not aware of the therapy undertaken, evaluated the patients.

Results

Significant improvements were noted in all groups with respect to all outcome parameters, except lateral flexion (P < 0.05).

Conclusions

Low power laser therapy seemed to be an effective method in reducing pain and functional disability in the therapy of chronic LBP. Lasers Surg. Med. 32:233–238, 2003. © 2003 Wiley‐Liss, Inc.
Nostalgia for early experience as a determinant of consumer preferences
Authors: Schindler Robert M. , Holbrook Morris B.
Published: March 2003

Studies of music, motion pictures, movie stars, and fashion products have shown that styles popular during a consumer's youth can influence the consumer's lifelong preferences. The authors present an integrative model of this phenomenon and propose that these nostalgic effects are not limited to products that relate to the arts and entertainment or are primarily aesthetic. As an illustrative example, the authors investigate the effects of early experience on consumer preferences for automobile styles. Consistent with expectations, they find that men do but women do not show evidence of nostalgic attachment to the styles experienced in their youth—that is, their preferences peaked for products that were popular when they were young. Also, as expected, individual differences in the psychographic variable of nostalgia proneness play a role in moderating these effects. These findings expand the understanding of the generality, the boundaries, and the managerial relevance of the age‐related peak‐preference phenomenon. © 2003 Wiley Periodicals, Inc.
A conceptual model of perceived customer value in e‐commerce: A preliminary investigation
Authors: Chen Zhan , Dubinsky Alan J.
Published: March 2003

This article presents an exploratory study of a conceptual model of perceived customer value in a business‐to‐consumer e‐commerce setting. Key precursors of perceived customer value included in the model are valence of on‐line shopping experience, perceived product quality, perceived risk, and product price. Relationships among these variables (as well as mediating variables) and their relationship to on‐line shoppers' value perceptions are explored. The theoretical framework proposed in this work expands on previous efforts on perceived customer value by including new variables relevant to an e‐commerce setting and by integrating several key variables into one model. The preliminary findings lead to several implications. © 2003 Wiley Periodicals, Inc.
Fhit gene alterations in hepatocarcinogenesis induced by a choline‐deficient L‐amino acid–defined diet in rats
Authors: Tsujiuchi Toshifumi , Sasaki Yasutaka , Oka Yasuo , Konishi Yoichi , Tsutsumi Masahiro
Published: March 2003

Alterations of the fragile histidine triad (Fhit) gene were investigated in rat hepatocarcinogenesis induced by a choline‐deficient L‐amino acid–defined (CDAA) diet. Males of the F344 strain, 6 wk of age, were fed a CDAA diet, and subgroups were killed at 2, 4, 12, 20, and 75 wk after the beginning of the experiment. Fifteen hepatocellular carcinomas (HCCs) were noted in rats by the last time point; they were dissected free from the surrounding tissue. Normal control liver specimens were obtained from 6‐wk‐old rats. Total RNAs were extracted from whole livers of animals fed the CDAA diet for 2, 4, 12, and 20 wk and from HCCs, for assessment of aberrant transcription of the Fhit gene by reverse transcription–polymerase chain reaction. Aberrant transcripts were detected in livers of rats fed the CDAA diet for 4, 12, and 20 wk, but not 2 wk, as well as in 11 of 15 HCCs (73.3%). Southern blot analysis showed a genomic DNA abnormality in one of seven informative HCCs (14.3%), while Western blot analysis showed reduction of Fhit protein expression in seven of nine HCCs (77.8%). No abnormal expression was evident in the livers after exposure to the CDAA diet for 2–20 wk. These results suggest that Fhit alterations may play important roles in hepatocarcinogenesis due to choline deficiency in rats. © 2003 Wiley‐Liss, Inc.
Requirement of c‐jun for testosterone‐induced sensitization to N‐(4‐hydroxyphenyl)retinamide–induced apoptosis
Authors: Shimada Keiji , Nakamura Mitsutoshi , Ishida Eiwa , Kishi Munehiro , Konishi Noboru
Published: March 2003

Androgen stimulation strongly affects the sensitivity to anticancer drug–induced apoptosis in prostate cancer cells. We investigated the influence of androgen stimulation with testosterone on N‐(4‐hydroxyphenyl)retinamide (4‐HPR)–induced apoptosis in the androgen‐sensitive prostate cancer cell line LNCaP. Overexpression of a dominant negative form of mitogen‐activated protein kinase kinase 7, a specific kinase of c‐jun NH2‐terminal kinase (JNK), significantly inhibited 4‐HPR–induced JNK activation and apoptosis and canceled the hormone‐dependent sensitization. Testosterone activated extracellular signal‐regulated kinase (ERK), activating protein‐1, subsequently increased the expression of c‐jun. In addition, testosterone significantly enhanced in vivo phosphorylation of c‐jun by 4‐HPR as well as JNK activation. Transfection with an antisense oligonucleotide of c‐jun blocked 4‐HPR‐induced apoptosis and the testosterone‐induced sensitization, suggesting a major contribution of the JNK/c‐jun mediated pathway in androgen‐dependent sensitization. Interestingly, inhibition of testosterone‐induced activation by PD98059 also canceled an upregulation of c‐jun and increased apoptosis. These results suggested that modulation of JNK activation and expression of c‐jun through ERK might have been essentially involved in androgen‐mediated sensitization to 4‐HPR‐induced apoptosis in prostate cancer cells. © 2003 Wiley‐Liss, Inc.
Cognitive effects of unilateral posteroventral pallidotomy: A 4‐year follow‐up study
Authors: Alegret Montse , Valldeoriola Francesc , Tolosa Eduardo , Vendrell Pere , Junqué Carme , Martínez José , Rumià Jordi
Published: March 2003

We assessed the long‐term neuropsychological effects of unilateral posteroventral pallidotomy in Parkinson's disease. Eleven Parkinson's disease patients, from an original cohort of 15 consecutive patients who underwent pallidotomy, were evaluated. A neuropsychological battery was administered to each patient before (3 days) and after (3 months and 4 years) surgery during the effects of levodopa. The following tests were administered: Rey's Auditory‐Verbal Learning Test, Visual Associative Learning test from the Wechsler Memory Scale‐Revised, Luria's motor alternation, Benton's Judgment of Line Orientation, Trail Making, phonetic verbal fluency, Stroop test, Petrides' working memory tasks, Beck's depression questionnaire and the Maudsley obsessional–compulsive inventory. In the 3‐month postoperative assessment, there was a significant worsening in phonetic verbal fluency and an improvement in Benton's Judgment of Line Orientation test. In the 4‐year follow‐up assessment, phonetic verbal fluency and Benton's Judgment of Line Orientation test returned to baseline scores. Although there was no significant difference between pre‐ and postsurgical scores for long‐term visual associative memory, there was a significant deterioration between 3‐month and 4‐year follow‐up performances. Our results suggest that unilateral posteroventral pallidotomy may produce transient changes in prefrontal and visuospatial functions, but there is no evidence of permanent neuropsychological effects.
Prevalence of PD and other types of parkinsonism in three elderly populations of central Spain
Authors: Benito‐León Julián , Bermejo‐Pareja Félix , Rodríguez Javier , Molina José‐Antonio , Gabriel Rafael , Morales José‐Manuel ,   for the Neurological Disorders in Central Spain (NEDICES) Study Group
Published: March 2003

The prevalence of Parkinson's disease (PD) and other types of parkinsonism in three elderly populations of central Spain was investigated using a door‐to‐door, two‐phase approach. This design called for the administration of a brief questionnaire to subjects 65 years of age or older taken from the census of one urban municipality of Greater Madrid (Margaritas, Getafe), one rural site (Arévalo County, Ávila), and one urban district of Madrid (Lista) in Spain (N = 5,278). Study neurologists extensively investigated those subjects who screened positively. The diagnoses, based on specified criteria, were reviewed to increase reliability across neurologists. We found 118 subjects with parkinsonism: 81 affected by PD (68.6%), 26 drug‐induced parkinsonism (22.0%), 6 parkinsonism in dementia (5.1%), 3 vascular parkinsonism (2.5%), and 2 unspecified parkinsonism (1.7%). The prevalence was 2.2% (95% confidence interval [CI], 1.8–2.6) for all types of parkinsonism and 1.5% (95% CI, 1.2–1.8) for PD. The prevalence estimates of parkinsonism and PD increased with age, declining at 85 years and over. Age prevalence ratios were higher for men. Twenty‐three subjects (28.4%) of the subjects with PD were detected through the screening and had not been diagnosed previously. Overall prevalence estimates of PD and other types of parkinsonism in central Spain rank at levels similar to those recently reported for other European and non‐European elderly populations. Despite improvement in access to health services, an important proportion of PD patients may never seek neurological attention. © 2002 Movement Disorder Society
One‐fascicle median nerve transfer to biceps muscle in C5 and C6 root avulsions of brachial plexus injury
Authors: Sungpet Adisak , Suphachatwong Chanyut , Kawinwonggowit Viroj
Published: March 2003

Five male patients with avulsions of the C5 and C6 roots of the brachial plexus underwent transfer of one fascicle of the median nerve to the motor branch of the biceps muscle. The mean period of follow‐up was 32 months. The average reinnervation time of the biceps was 3.4 months. Four patients achieved biceps strength of Medical Research Council (MRC) grade 4, and one patient had strength of the biceps of MRC grade 3. The mean period of time from surgery to MRC grade 3 was 9 months. At the last follow‐up examination, grip strength, pinch strength, moving two‐point discrimination, and strength of wrist volar flexion on the affected side were not worse than before the operation in any patient. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:10–13 2003
Primary nerve grafting: A study of revascularization
Authors: Chalfoun Charbel , Scholz Thomas , Cole Matthew D. , Steward Earl , Vanderkam Victoria , Evans Gregory R.D.
Published: March 2003

It was the purpose of this study to evaluate the revascularization of primary nerve repair and grafts using orthogonal polarization spectral (OPS) (Cytometrix, Inc.) imaging, a novel method for real‐time evaluation of microcirculatory blood flow. Twenty male Sprague Dawley rats (250 g) were anesthetized with vaporized halothane and surgically prepared for common peroneal nerve resection. Group I animals (n = 10) underwent primary neurorraphy following transection, utilizing a microsurgical technique with 10‐0 nylon suture. Group II (n = 10) animals had a 7‐mm segment of nerve excised, reversed, and subsequently replaced as a nerve graft under similar techniques. All animals were evaluated using the OPS imaging system on three portions (proximal, transection site/graft, and distal) of the nerve following repair or grafting. Reevaluation of 5 animals randomly selected from each group using the OPS imaging system was again performed on days 14 and 28 following microsurgical repair/grafting. Values were determined by percent change in vascularity of the common peroneal nerve at 0 hr following surgery. Real‐time evaluation of blood flow was utilized as an additional objective criterion. Percent vascularity in group I and II animals increased from baseline in all segments at day 14. By day 28, vascularity in nerves of group I rats decreased in all segments to values below baseline, with the exception of the transection site, which remained at a higher value than obtained directly after surgical repair. In group II animals, vascularity remained above baseline in all segments except the distal segment, which returned to vascularity levels similar to those at 0 hr. Further, occlusion of the vessels demonstrated in the graft and distal segments following initial transection appeared to be corrected. This study suggests that revascularization may occur via bidirectional inosculation with favored proximal vascular growth advancement. The use of real‐time imaging offers a unique evaluation of tissues through emerging technologies. © 2003 Wiley‐Liss, Inc. MICROSURGERY 23:60–65 2003
Non‐linear stability and convection for laminar flows in a porous medium with Brinkman law
Authors: Lombardo S. , Mulone G.
Published: March 2003

The non‐linear stability of plane parallel shear flows in an incompressible homogeneous fluid heated from below and saturating a porous medium is studied by the Lyapunov direct method.In the Oberbeck–Boussinesq–Brinkman (OBB) scheme, if the inertial terms are negligible, as it is widely assumed in literature, we find global non‐linear exponential stability (GNES) independent of the Reynolds number R. However, if these terms are retained, we find a restriction on R (depending on the inertial convective coefficient) both for a homogeneous fluid and a mixture heated and salted from below. In the case of a mixture, when the normalized porosity ε is equal to one, the laminar flows are GNES for small R and for heat Rayleigh numbers less than the critical Rayleigh numbers obtained for the motionless state. Copyright © 2003 John Wiley & Sons, Ltd.
A well‐posed problem for electromagnetic media with quadrupoles
Authors: Bosello Carlo Alberto , Nibbi Roberta
Published: March 2003

In this paper, we consider a non‐local electromagnetic medium for which the quadrupole term in the electric induction is not negligible. After giving an outline of the physical model, the problem of Maxwell equations for such a medium is addressed by proving existence and uniqueness of solutions and a principle of constrained minimum is shown to hold as a consequence of some thermodynamical restrictions. Copyright © 2003 John Wiley & Sons, Ltd.
The auto‐correlation equation on the finite interval
Authors: Von Wolfersdorf L.
Published: March 2003

Applying the Fourier cosine transformation, the quadratic auto‐correlation equation on the finite interval [0,T] of the positive real half‐axis ℝ+ is reduced to a problem for the modulus of the finite complex Fourier transform of the solution. From the solutions of this problem L2‐solutions of the auto‐correlation equation are obtained in closed form. Moreover, as in the case of the equation on ℝ+ a Lavrent'ev regularization procedure for the auto‐correlation equation is suggested. Copyright © 2003 John Wiley & Sons, Ltd.
Scattering by a side‐rounded rectangular iris in rectangular waveguides
Authors: Jiang Zhihua , Shen Zhongxiang
Published: March 2003

This paper presents a formally exact mode‐matching analysis of scattering by a side‐rounded rectangular iris in rectangular waveguides. The complete set of modes in a rectangular waveguide with rounded sides is used in the mode‐matching formulation for the junction between a small side‐rounded rectangular waveguide and a large rectangular waveguide, based on the plane wave series expansion of Bessel function. Numerical results for the scattering parameters of a rectangular waveguide loaded with a side‐rounded rectangular iris are presented and compared with measurements. Excellent agreement is observed in all the cases considered. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 118–121, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10841
Dispersion properties of photonic crystal fibers
Authors: Sinha R. K. , Varshney Shailendra K.
Published: March 2003

The dispersion properties of silica‐based photonic crystal fibers (PCFs) are analyzed to obtain: (i) zero dispersion at any wavelength, (ii) nearly zero ultraflattened dispersion, and (iii) a very high negative chromatic dispersion for various designs of PCFs. The influence of normalized air hole size on zero dispersion wavelength is also reported. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 129–132, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10845
A two‐step calibration technique for measuring S‐parameters of transitional structures
Authors: Li Chao , Shen Zhongxiang , Law Choi Look
Published: March 2003

A new two‐step calibration technique to directly measure the scattering parameters of asymmetrical transitional structures is proposed in this article. This technique conducts two calibrations, each one of them for one type of the transition's two ports, and two error boxes associated with the transition measurement system can then be obtained, with which the transition's raw measured data can be corrected. Experimental studies have verified the validity of the formulation and the accuracy of the two‐step calibration technique. The technique can be extensively used to measure the scattering parameters of transitional structures without resorting to constructing back‐to‐back test fixtures. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 132–135, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10846
Increments for 1H and 13C NMR chemical shifts in areneboronic acids
Authors: Bruns Stefan , Sinnwell Volker , Voss Jürgen
Published: March 2003

A series of areneboronic acids were studied by NMR spectroscopy. Increments for the 1H and 13C chemical shifts caused by the boronic acid substituent B(OH)2 in areneboronic acids were determined. Copyright © 2003 John Wiley & Sons, Ltd.
Complete 1H and 13C assignments of some epipodophyllotoxin derivatives
Authors: No Zaesung , Lee Sueg‐Geun
Published: March 2003

The complete analyses of the 1H and 13C NMR spectra of the ortho ester analogues of etoposide are reported and differentiation of the α and β isomers of these derivatives is suggested by using the γ‐gauche effect upon the 13C chemical shift. Copyright © 2003 John Wiley & Sons, Ltd.
Two approaches to measure amplitude changes of the sensory nerve action potential over a length of nerve
Authors: van Aken Stefan F.J. , van Dijk J. Gert
Published: March 2003

Changes in amplitude of sensory nerve action potentials (SNAPs) over a length of nerve have not been used for diagnostic purposes. We measured such changes for median and ulnar nerves in 25 healthy subjects in two ways. The multiple‐stimulation method involved three stimulation sites (palm, wrist, elbow) and one recording site on a finger. The multiple‐recording method involved stimulation at the wrist and simultaneous recording from two adjacent sites on a finger. Percentile changes in amplitude could be measured in all subjects for the median nerve, but not for the ulnar nerve due to submaximal stimulation in the palm. For the median nerve, the multiple‐recording method resulted in a mean amplitude change of 79% ± 13%, whereas comparison of wrist to palm stimulation in the multiple‐stimulus method resulted in a change of 73% ± 10%. These values are high enough to encourage study into practical applications of such methods in detecting peripheral nerve disease. © 2003 Wiley Periodicals, Inc. Muscle Nerve 27: 297–301, 2003
Water‐immersion wrinkling is due to vasoconstriction
Authors: Wilder‐Smith Einar P.V. , Chow Adeline
Published: March 2003

The underlying mechanism of the water‐immersion skin wrinkling test, which is used as a test of sympathetic nerve function, remains elusive. We investigated changes of blood circulation in the hand occurring with water‐immersion wrinkling by measuring the velocity of ulnar and digital artery blood flow, and of digit skin blood flow, in healthy subjects before and during wrinkling. Wrinkling was accompanied by significant reduction in blood flow velocity in all vessels, with a maximum in digital vessels. Our data show that water‐immersion wrinkling is a function of digit pulp vasoconstriction. This test of sympathetic function can now be quantified using parameters of blood flow velocity, enabling its more widespread and accurate use. Muscle Nerve 27: 307–311, 2003
Analysis of a finite‐buffer bulk‐service queue with discrete‐Markovian arrival process: D‐MAP/Ga,b/1/N
Authors: Chaudhry M.L. , Gupta U.C.
Published: March 2003

Discrete‐time queues with D‐MAP arrival process are more useful in modeling and performance analysis of telecommunication networks based on the ATM environment. This paper analyzes a finite‐buffer discrete‐time queue with general bulk‐service rule, wherein the arrival process is D‐MAP and service times are arbitrarily and independently distributed. The distributions of buffer contents at various epochs (departure, random, and prearrival) have been obtained using imbedded Markov chain and supplementary variable methods. Finally, some performance measures such as loss probability and average delay are discussed. Numerical results are also presented in some cases. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 345–363, 2003.
Using Lagrangean relaxation to minimize the weighted number of late jobs on a single machine
Authors: Dauzère‐Pérès Stéphane , Sevaux Marc
Published: March 2003

This paper tackles the general single machine scheduling problem, where jobs have different release and due dates and the objective is to minimize the weighted number of late jobs. The notion of master sequence is first introduced, i.e., a sequence that contains at least an optimal sequence of jobs on time. This master sequence is used to derive an original mixed‐integer linear programming formulation. By relaxing some constraints, a Lagrangean relaxation algorithm is designed which gives both lower and upper bounds. The special case where jobs have equal weights is analyzed. Computational results are presented and, although the duality gap becomes larger with the number of jobs, it is possible to solve problems of more than 100 jobs. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 50: 2003
Threshold optimization for weighted voting classifiers
Authors: Levitin G.
Published: March 2003

Weighted voting classifiers considered in this paper consist of N units each providing individual classification decisions. The entire system output is based on tallying the weighted votes for each decision and choosing the one which has total support weight exceeding a certain threshold. Each individual unit may abstain from voting. The entire system may also abstain from voting if no decision support weight exceeds the threshold. Existing methods of evaluating the reliability of weighted voting systems can be applied to limited special cases of these systems and impose some restrictions on their parameters. In this paper a universal generating function method is suggested which allows the reliability of weighted voting classifiers to be exactly evaluated without imposing constraints on unit weights. Based on this method, the classifier reliability is determined as a function of a threshold factor, and a procedure is suggested for finding the threshold which minimizes the cost of damage caused by classifier failures (misclassification and abstention may have different price.) Dynamic and static threshold voting rules are considered and compared. A method of analyzing the influence of units' availability on the entire classifier reliability is suggested, and illustrative examples are presented. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 322–344, 2003.
When is model complexity too much? Illustrating the benefits of simple models with Hughes' salvo equations
Authors: Lucas Thomas W. , McGunnigle John E.
Published: March 2003

The simulations that many defense analysts rely upon in their studies continue to grow in size and complexity. This paper contrasts the guidance that the authors have received—from some of the giants of military operations research—with the current practice. In particular, the analytic utility of Hughes' simple salvo equations is compared with that of the complex Joint Warfighting System (JWARS), with respect to JWARS' key performance parameters. The comparison suggests that a family of analytic tools supports the best analyses. It follows that smaller, more agile, and transparent models, such as Hughes' salvo equations, are underutilized in defense analyses. We believe that these models should receive more attention, use, and funding. To illustrate this point, this paper uses two very simple models (by modern standards) to rapidly generate insights on the value of information relative to force strength. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2003
Dendritic morphology is altered in hippocampal neurons following prenatal compromise
Authors: Dieni Sandra , Rees Sandra
Published: March 2003

Chronic placental insufficiency (CPI), a known cause of intrauterine growth restriction, can lead to structural alterations in the developing brain that might underlie postnatal neurological deficits. We have previously demonstrated significant reductions in the volumes of hippocampal neuropil layers in fetal guinea pig brains following experimentally induced growth restriction. To determine the components of the neuropil affected in the brains of growth restricted (GR) fetuses, the dendritic morphology of CA1 pyramidal neurons and dentate granule cells was examined. CPI was induced by unilateral uterine artery ligation in pregnant guinea pigs at midgestation (term ≈67days). Hippocampi from control and GR fetuses were stained using the Rapid Golgi technique and the growth and branching of the dendritic arbors were quantified using the Sholl method. In addition, the density of dendritic spines was determined on the apical arbors of each population. In GR brains (n = 7) compared to controls (n = 7), there was a reduction in dendritic elongation (p < 0.005) and an alteration in the branch point distribution in CA1 basal arbors, and a reduction both in the outgrowth (p < 0.05) and branch point number (p < 0.05) of CA1 apical arbors. Dentate granule cells from GR brains also demonstrated reduced dendritic outgrowth (p < 0.05). There was an increase in dendritic spine density in both neuronal populations; this might be due either to altered synaptic pruning or as a compensatory mechanism for reduced dendritic length. These findings demonstrate that a chronic prenatal insult causes selective changes in the morphology of hippocampal cell dendrites and may lead to alterations in hippocampal function in the postnatal period. © 2003 Wiley Periodicals, Inc. J Neurobiol 55: 41–52, 2003
Amputation‐induced activity of progenitor cells leads to rapid regeneration of olfactory tissue in lobsters
Authors: Harrison Paul J. H. , Cate Holly S. , Steullet Pascal , Derby Charles D.
Published: March 2003

Lobsters have a self‐renewing olfactory system and, like many animals, continuously replace old or dying olfactory receptor neurons. In addition, lobsters are able to regenerate the peripheral olfactory system even after complete loss. The olfactory sensors in lobsters are located distally on a pair of antennules. These antennules are often damaged, but this has little impact on the lobster's sense of smell because damaged olfactory tissue is rapidly replaced. In this study, we investigated damage‐induced regeneration of the olfactory system by measuring cell proliferation following controlled amputation. We show that amputation‐induced regeneration occurs as a result of up‐regulating the normal development of olfactory sensors. A unique feature of up‐regulated development is the formation of patches of proliferating cells within the antennular epithelium. Epithelial patches were typically formed between 3 and 10 days postamputation on the amputated side. They were characterized by their: proximal position with respect to developing clusters of olfactory receptor neurons (ORNs); tendency to form two discrete patches within the borders of each existing annulus; cell size, which was approximately twice that of mature ORNs; and location within the ventral epithelium. The development of epithelial patches was immediately followed by proliferation of clusters of ORNs and associated glial cells, and the level of this proliferation increased significantly during the premolt stage of the lobster's molt cycle. These epithelial patches may represent populations of precursor cells, because they develop in response to amputation and immediately precede development of cell clusters composed of ORNs and glia. Possible regulatory signals controlling epithelial patch development are discussed. © 2003 Wiley Periodicals, Inc. J Neurobiol 55: 97–114, 2003
Post‐buckling analysis of imperfect laminates using finite strips based on a higher‐order plate theory
Authors: Zou G. P. , Lam S. S. E.
Published: March 2003

A finite strip procedure has been developed for the post‐buckling analysis of composite laminates when subjected to progressive end shortening. The finite strips are developed based on a higher‐order shear deformation plate theory and there are nine variables at each nodal line. Initial imperfection expressed in the form of suitable trigonometric function is allowed. Examples including isotropic plates and laminates with arbitrary lay‐up arrangement are presented. Numerical results for laminates with and without initial imperfection are used to illustrate the effect of imperfection. Copyright © 2003 John Wiley & Sons, Ltd.
Numerical model of electrical potential within the human head
Authors: Nixon J. B. , Rasser P. E. , Teubner M. D. , Clark C. R. , Bottema M. J.
Published: March 2003

A realistic subject‐specific human head model was constructed based on structural magnetic resonance imaging (sMRI) data. Electrical conductivities were assigned inhomogeneously according to tissue type and variability within each head segment. A three‐dimensional (3D) finite‐difference method (FDM) was used to compute the evolution of the electrical potential from a single electrical dipole within the brain. The Douglas–Rachford FDM and three versions of iterative FDM were tested on a three‐layer concentric sphere model. The successive over‐relaxation (SOR) iterative method showed the best convergence properties and hence was used to compute the electrical potential within a realistic head model. The effect of using inhomogeneous rather than homogeneous conductivities within head segments of this model was shown to be important. Copyright © 2003 John Wiley & Sons, Ltd.
A refined non‐linear non‐conforming triangular plate/shell element
Authors: Zhang Y. X. , Cheung Y. K.
Published: March 2003

A refined non‐conforming triangular plate/shell element for geometric non‐linear analysis of plates/shells using the total Lagrangian/updated Lagrangian approach is constructed in this paper based on the refined non‐conforming element method for geometric non‐linear analysis. The Allman's triangular plane element with vertex degrees of freedom and the refined triangular plate‐bending element RT9 are used to construct the present element. Numerical examples demonstrate that the accuracy of the new element is quite high in the geometric non‐linear analysis of plates/shells. Copyright © 2003 John Wiley & Sons, Ltd.
Small, minority‐based nonprofits in the information age
Authors: Schneider Jo Anne
Published: March 2003

Pundits of information technology stress that the Internet opens new arenas for nonprofits through the ability to
share information both locally and globally. New technology also changes funders' and other evaluators'
expectations regarding proposals.

Although new technology makes life easier for organizations with budgets, time, and familiarity with technology
to buy and use these new tools, nonprofits that lack these resources fall even further behind in their quest to
support and improve their programs. Based on ethnographic research in Kenosha, Wisconsin, this article explores the
role of changing technology in the ability of small nonprofits to succeed in implementing their organizational
mission. Using case studies, this article compares the experience of nonprofits and church mission projects based in
the African American and Latino communities in this small city to that of two mainstream organizations in gaining
funding and the general perception of those agencies in the local community. The article argues that expectations
about the use of technology increase the gaps between a community's haves and have‐nots. Kenosha
organizations based in communities of color are particularly at risk due to already low funding and lack of staff
familiar with new technologies. The article demonstrates that the key is often not access to technology or technical
assistance but the time to make the best use of available technology.
Performance evaluations of for‐profit and nonprofit U.S. hospitals since 1980
Authors: Rosenau Pauline Vaillancourt
Published: March 2003

This synthesis of studies examines whether the published literature shows an evidence‐based consensus
on performance differences between private for‐profit and nonprofit hospitals in the United States since
1980. The author systematically and comprehensively surveyed peer‐reviewed publications to clarify this
question. The author's second objective was to learn what proportion of all research assessing
for‐profit and nonprofit health care providers is devoted to hospitals compared to all other providers.
The third goal was to discover how any trends in observed performance differences among hospitals compare with
trends among other provider types.

Computerized bibliographic searches of all relevant databases yielded seventy‐five studies
(ninety‐three assessments) that compared the performance of for‐profit and nonprofit
hospitals on four performance criteria: access, quality, cost or efficiency, and amount of charity care. The
author coded findings on performance in one of three ways: for‐profit superiority, nonprofit
superiority, or inconclusive. Most studies (60 percent) reported that nonprofit hospitals have better
relative performance than for‐profit hospitals, clear evidence of their organizational effectiveness.
Thirty‐one percent were inconclusive, and 8 percent reported that for‐profits were better.
Neural correlates of visual perceptual learning in humans indexed by event‐related potentials
Authors: Ding Yulong , Song Yan , Fan Silu , Chen Lin
Published: March 2003

The current work investigated the neural correlates of visual perceptual learning by recording event‐related potentials (ERPs) from human adults. Subjects were trained with a discrimination task of arrow orientation in three consecutive training sessions within 2 hours. While reaction times (RTs) were shortened gradually across training sessions, the amplitudes of negativities between 125–155 ms (N1) and between 290–340 ms (N2) decreased mainly over the central and parietal areas respectively. However, a broadly distributed P3 component increased along with more practice. In addition, the decrease in N1 and increase in P3 preceded the decrease in N2. The implications of these results to the neural mechanisms subserving perceptual learning are discussed.