bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detecting Bacillus cereus spores on a mail sorting system using Raman spectroscopy
Authors: Farquharson Stuart , Grigely Lawrence , Khitrov Victor , Smith Wayne , Sperry Jay F. , Fenerty Gerard 
Published: January 2004

AbstractThe ability of Raman spectroscopy to detect anthrax‐causing spores as they pass through a mail sorting system was investigated. A pump was connected to an existing vacuum manifold on a commercial sorter, and a filter designed to capture 0.5–3 µm particles was placed in‐line. A standard business letter containing 0.23 g of Bacillus cereus spores, a Bacillus anthracis surrogate, was placed in a stack of 20 letters and passed through the system. Raman spectra of the filter positively identified the captured material as bacterial spores by the dominant calcium dipicolinate Raman spectral bands associated with the spore core. A limit of detection, using 400 mW of 785 nm laser excitation for a 1‐s acquisition, is estimated at 4.5 mg. The ability of a Raman spectroscopy based system to detect and prevent the distribution of a letter containing gram levels of anthrax spores is discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Numerical study of polarization‐dependent focusing for a bilayer planar FSS reflective lens at millimeter wavelengths
Authors: Bliznyuk Natalia , Engheta Nader 
Published: January 2004

AbstractIn this paper, we numerically analyze the polarization‐dependent focusing properties of a planar reflective lens formed by two parallel layers of nonuniform “gangbuster” surfaces (GSs) above a ground plane. Since these GSs consist of superdense arrays of thin finite‐length parallel metallic wires, the desired phase patterns on such a lens surface are achieved by adjusting the lengths of these metallic wires for appropriate polarization components. In our analysis, we use the method of moments (MoM) and the transmission‐lines analogy, along with the surface‐equivalence theorem, to estimate the field intensity in the focal plane. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 361–365, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11382
Efficient methods for inductance calculation with special emphasis on nonuniform current distributions
Authors: Ooi Ban‐Leong , Xu Dao‐Xian , Guo Li‐Hui 
Published: January 2004

AbstractTwo efficient methods of inductance calculations for spiral inductor with special emphasis on nonuniform current distribution on the metallic trace are presented. Based on the conventional magnetic‐flux method and the energy method, a unified approach for modeling the eddy current and skin depth of the spiral inductor has been presented. Our proposed method is validated with experimental results, and good agreement is obtained. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 432–436, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11402
A 2D‐TLM model for electromagnetic wave propagation in Tellegen media
Authors: Cabeceira Ana C. L. , Barba Ismael , Grande Ana , Represa José 
Published: January 2004

AbstractA TLM model suitable to simulate the propagation of electromagnetic waves in Tellegen media is presented. The angle tilt between electromagnetic field vectors, the intrinsic impedances and the effective parameters of the medium are computed. The results for a monochromatic source are in very good agreement with the analytical solution. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 438–441, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11404
Numerical modelling of the propagation of fast landslides using the finite element method
Authors: Quecedo M. , Pastor M. , Herreros M. I. , Fernández Merodo J. A. 
Published: January 2004

AbstractThis paper proposes a two‐dimensional (2D) model for the analysis of the propagation of fast landslides involving a fluidized material such as debris and mud flows, flowslides and avalanching flows. The model is based on the Navier–Stokes depth‐integrated equations. To incorporate the effect of steep slopes and centrifugal forces due to the high velocities characterizing the flowslides and the bed curvature, a curvilinear system of reference is used. The corresponding equations of motion are complemented by depth‐averaged constitutive equations and bed friction laws.The resulting set of differential equations are solved using the two‐step Taylor–Galerkin algorithm. This algorithm has been used by the authors to solve hydraulic and dam‐break problems using the finite element method. Owing to the importance of the source term compared to the advection component, the proposed algorithm follows a splitting scheme using a fourth‐order Runge–Kutta method for integrating the friction and slope components.The performance of the overall approach has been checked in a number of examples. The analysis of the results provides insights into the key elements of the model and shows the adequacy of the method to solve real problems where merging and splitting of the flow occur. Copyright © 2004 John Wiley & Sons, Ltd.
A novel non‐linearly explicit second‐order accurate L‐stable methodology for finite deformation: hypoelastic/hypoelasto‐plastic structural dynamics problems
Authors: Zhou X. , Sha D. , Tamma K. K. 
Published: January 2004

AbstractA novel non‐linearly explicit second‐order accurate L‐stable computational methodology for integrating the non‐linear equations of motion without non‐linear iterations during each time step, and the underlying implementation procedure is described. Emphasis is placed on illustrative non‐linear structural dynamics problems employing both total/updated Lagrangian formulations to handle finite deformation hypoelasticity/hypoelasto‐plasticity models in conjunction with a new explicit exact integration procedure for a particular rate form constitutive equation. Illustrative numerical examples are shown to demonstrate the robustness of the overall developments for non‐linear structural dynamics applications. Copyright © 2004 John Wiley & Sons, Ltd.
A computational approach for multi‐scale analysis of heterogeneous elasto‐plastic media subjected to short duration loads
Authors: Chung Peter W. , Tamma Kumar K. , Namburu Raju R. 
Published: January 2004

AbstractThe asymptotic expansion homogenization (AEH) approach has found wide acceptance for the study of heterogeneous structures due to its ability to account for multi‐scale features. The emphasis of the present study is to develop consistent AEH numerical formulations to address elasto‐plastic material response of structures subjected to short‐duration transient loading. A second‐order accurate velocity‐based explicit time integration method, in conjunction with the AEH approach, is currently developed that accounts for large deformation non‐linear material response. The approach is verified under degenerate homogeneous conditions using existing experimental data in the literature and its ability to account for heterogeneous conditions is demonstrated for a number of test problems. Copyright © 2004 John Wiley & Sons, Ltd.
Hydrostatic fluid loading in non‐linear finite element analysis
Authors: Rumpel T. , Schweizerhof K. 
Published: January 2004

AbstractDeformation dependent pressure loading on solid structures is created by the interaction of fluids with the deformable surface of a structure. Such fairly simple load models are valid for static and quasi‐static analyses and they are a very efficient tool to represent the influence of a fluid on the behaviour of structures. Completing previous studies on the deformation dependence of the loading with the assumption of finite gas volumes, the current contribution focuses on the influence of modifications of the size and shape of a finite structure containing an incompressible fluid with a free surface. The linearization of the corresponding virtual work expression necessary for a Newton‐type solution leads to additional terms for the volume dependence. Investigating these terms the conservativeness of the problem can be proven by the symmetry of the linearized form. Similarly to gas loading, the discretization of the structure with finite elements leads to standard stiffness matrix forms plus the so‐called load stiffness matrices and a rank‐one update for each filled structure part, if the loaded surface segments are identical with element surfaces. Some numerical examples show the effectiveness of the approach and the necessity to take the corresponding terms in the variational expression and the following linearization into account. Copyright © 2004 John Wiley & Sons, Ltd.
Adaptive methods for thermomechanical coupled contact problems
Authors: Rieger A. , Wriggers P. 
Published: January 2004

AbstractIn this paper an adaptive method for the analysis of thermomechanical coupled multi‐body contact problems is presented. The method is applied to non‐linear elastic solids undergoing finite (thermal) deformations. The contact model considers non‐linear pressure‐dependent heat flux as well as frictional heating in the interface. A time–space‐finite element discretization of the governing equations is formulated including unilateral constraints due to contact. A staggered solution algorithm has been constructed that allows an independent spatial discretization of the coupled subproblems. A posteriori projection‐based error estimators, which enforce implicitly the special boundary conditions due to thermal contact, are used to control the spatial discretization as well as the adaptive time stepping. Numerical examples are presented to corroborate the applicability of the adaptive algorithm to the considered problem type. Copyright © 2004 John Wiley & Sons, Ltd.
Post‐inhibitory rebound properties of dopaminergic cells of the ventral tegmental area
Authors: Paul Kush , Johnson Steven W. 
Published: January 2004

AbstractWe have investigated the post‐inhibitory rebound (PIR) properties of dopamine cells in the ventral tegmental area of the rat midbrain. Using microelectrodes to record intracellularly from rat cells in the midbrain slice, we found that 54% of all recorded DA cells exhibited rebound depolarization in the presence of TTX. We observed primarily two types of rebound responses distinguished by their maximum amplitude and inactivation time constant, which we have termed as the ‘slowly inactivating PIR’ and low‐threshold spike (LTS). 35% of DA cells exhibited a ‘slowly inactivating PIR’ and 19% showed LTS. A subset of the latter exhibited repetitive LTS. The PIR was enhanced in high K+ medium and suppressed in low‐calcium medium. Under voltage clamp conditions, inward rebound currents at the end of a hyperpolarizing voltage step were partially blocked by specific T‐type channel blocker, Ni2+. Repetitive LTSs were reversibly changed to single LTS by blocking the potassium SK current.
Ethanol intoxication reduces, whereas ethanol withdrawal transiently enhances, production of the neural progenitor cells in the adult mouse dentate gyrus
Authors: Jaako K. , Zharkovsky T. , Kaasik A. , Zharkovsky A. 
Published: January 2004

AbstractThe hippocampus is one of the brain areas where neurogenesis persists during adulthood. To determine whether chronic ethanol administration affects production of the new cells in the dentate gyrus adult mice received ethanol via the inhalation route for 4 weeks and newly born cells were determined after administration of the proliferation marker bromodeoxyuridine (BrdU). An inhibition of the generation of the new cells at the end of ethanol intoxication was observed, whereas ethanol withdrawal induced a transient increase in the number of dividing cells in the dentate gyrus. The differentiation of the newly born cells into mature calbindin‐positive neurons during ethanol intoxication or withdrawal was retarded. Although the functional significance of the observed changes is not known, we suggest that retardation of the differentiation of the new cells following ethanol administration might have an impact on the ethanol‐induced impairment of hippocampal functions.
The effects of the inhaled formaldehyde during the early postnatal period in the hippocampus of rats: A morphological and immunohistochemical study
Authors: Songur Ahmet , Akpolat Nusret , Kus Ilter , Ozen Oguz Aslan , Zararsiz Ismail , Sarsilmaz Mustafa 
Published: January 2004

AbstractThe aim of this study was to investigate the effects of formaldehyde (FA) gas inhalation during the early postnatal period on the heat shock proteins 70 kDa (Hsp70) synthesis and morphological changes in the hippocampus in developmental process of rats and to determine whether the changes was reversible or not.Neonatal rats were exposed to 0 (control), 6 and 12 ppm FA gas throughout 30 day period following the birth. After the exposure to FA, some animals from each concentration group were decapitated at the day 30. Despite cessation of FA exposure, other groups were left for decapitation until the days of 60th and 90th. The brain samples were stained with Hsp70 as immunohistochemically and H&E. In the samples, pyramidal cell layer in the hippocampus was examined. Hsp70(+) neurons were found in the hippocampus of rats that inhaled FA on the 30th day. Furthermore, a considerable increase on the count of pyknotic neurons in these groups. But, on the other hand, in the 60th and 90th days, Hsp70 immunostaining and the count of pyknotic cells were found to be diminishing in FA inhaled groups.In conclusion, inhalation of FA gas in cytotoxic concentrations during early postnatal period causes increase in Hsp70 synthesis and damages the rat's hippocampus. Diminishment or disappearance of these negative changes in the 60th and 90th days indicates a reversible change in rats.
Microglial response to early ischemia‐induced changes in the rat spinal cord
Authors: Saganová Kamila , Mars̆ala Jozef , Ondrejc̆ák Tomás̆ , Vanický Ivo , Gálik Ján 
Published: January 2004

AbstractWe examined the early microglial response to spinal cord ischemia induced by occlusion of the descending aorta for 15 min, or more limited aortic occlusion (8, 10, 12 min( linked with blood volume reduction. The recovery of motor function and activation of microglia labeled by Griffonia simplicifolia B4‐isolectin (GSA I‐B4‐HRP) were assessed up to 7 days post‐ischemia. Activation of resident microglia characterized by both increased lectin binding and altered morphology was observed >48 hrs post‐ischemia. Massive infiltration of the microglia/macrophages related to the severity of ischemic insult appeared at day 3. Our data suggest that (1) ischemia of different degrees gives rise to a generalized microglial response at the early post‐ischemic phase; (2) graded activation of microglia/macrophases as a response to ischemic neuronal injury occurs within 48–72 hrs of post‐ischemic reperfusion; (3) lectin labeling of microglia can serve for continuous study of the evolution of pathological changes associated with transient spinal cord ischemia.
In vitro modulation of protein kinase CK2‐mediated phosphorylation of the neuronal growth‐associated protein B‐50 (GAP‐43)
Authors: Dokas Linda A. , Haas Michael S. , Lilly Scott M. , Ting Shu‐mei , Dennis Allison M. 
Published: January 2004

AbstractThe presynaptic protein B‐50 (GAP‐43) is a protein kinase CK2 (CK2) substrate phosphorylated in vitro in a polylysine‐dependent manner. Polylysine was compared to other basic compounds to further define characteristics of this phosphorylation. Total histone stimulated CK2 to a similar extent, but at higher concentrations than did polylysine, while spermine was without effect. Histone H2A accounted for the stimulatory effect of the mixed histone. Correlation between CK2 activity and the length of polylysine was observed. Polylysine‐dependent B‐50 phosphorylation was observed with both recombinant human CK2 and purified rat brain CK2. Serine/threonine phosphorylation occurred on the fragment, B‐501–132, and serine phosphorylation on B‐50133–226. Phosphorylation of B‐50 by CK2 was inhibited by actin and calmodulin. These results suggest that local interactions between CK2, basic proteins and/or actin at the neuronal membrane and calmodulin binding may determine the phosphorylated state of B‐50 at CK2 sites.
Age‐related changes in properties of cortically projecting basal forebrain neurons
Authors: Tanaka Junichi , Nishimura Jun‐ichi , Kimura Fukuko 
Published: January 2004

AbstractElectrophysiological properties of basal forebrain (nucleus basalis area) neurons projecting directly to the frontal cortex were studied in urethane‐anesthetized young and old male rats. Extracellular recordings demonstrated a total of 75 neurons (35 young and 40 old cells) which were antidromically activated by electrical stimulation of the frontal cortex. Post‐antidromic orthodromic excitatory responses were seen, and the number of neurons showing such an orthodromic excitation was significantly smaller in aged rats. No significant differences were observed between young and aged rats in the threshold, latency or the conduction velocity of antidromic activation, or in the spontaneous firing rate of driven cells. The absolute refractory period was significantly longer and the degree of successful antidromic propagation into the somatodendritic complex was significantly lower in aged rats. The data provide evidence that there are marked changes with age in the physiological properties of basal forebrain neurons projecting to the frontal cortex.
Effect of penicillin‐induced epilepsy seizure on the volume of hippocampus stratum pyramidalis in rat
Authors: Unal Nedim , Akdogan Ilgaz , Adiguzel Esat , Ozdemir Bülent , Tufan A. Cevik 
Published: January 2004

AbstractExperimental epileptic models have been developed to assess the pathophysiology of epileptic seizures. We have previously shown that epileptic seizures cause significant neuronal loss in hippocampus (p < 0.05). This study was undertaken to estimate the volume of rat hippocampus stratum pyramidalis in a penicillin‐induced epilepsy model, using a stereological method, i.e., “Cavalieri method”. Either 500 UI penicillin‐G in 0.1 ml or the same volume of saline was administered intracortically. A week later, animals were decapitated, their brains were removed by craniotomy, frozen and cut at a thickness of 150 μm in a cryostat. Sections were stained with hematoxylin‐eosin. The total and individual volumes of stratum pyramidalis layer of CA1, CA2 and CA3 subfields of hippocampus were then estimated. Results showed that unlike the decrease in the number of hippocampal neurons, the decrease in the total volume of hippocampus in experimental group of rats (4.55 ± 0.31 mm3) was not statistically significant compared to that of control group of rats (4.67 ± 0.25 mm3; p > 0.05). This study suggests that the loss of hippocampal neurons in penicillin‐induced epilepsy seizure is not directly correlated with a volume change in the hippocampus. Furthermore, our results indicate that it is important to assess both the neuron number and the volume of the affected area using stereological methods in an epilepsy model to objectively analyze the effects of the seizure.
p53, bcl‐2 Protein expression and the level of cerebral blood flow at the ischemic penumbra in rats
Authors: Park Seung Won , Kim Young Baeg , Min Byung Kook , Hwang Sung Nam , Kwon Jeong Taik , Suk Jong Sik 
Published: January 2004

AbstractWe investigated the spatial characteristics of apoptotic genes expression and CBF at the ischemic penumbra. A delayed focal cerebral infarction was created in twelve adult Sprague‐Dawley rats. Immunohistochemical staining of bcl‐2 and p53 proteins and TUNEL staining for apoptosis were performed. The peri‐infarct area was divided into six sectors by distance from the infarction border. Local CBF was measured at 2 mm distal to the presumed MCA occlusion site preoperatively, and at 2 mm and 8 mm distal to the MCA occlusion site intraoperatively. TUNEL‐positive, bcl‐2 or p53 positive cells were concentrated as it went closer to the infarction core and reduced peripherally, which was inversely proportional to the local CBF. The area encompassed by the border of the p53 area was 3.3 ± 0.2 times of the infarction core. The p53 area seems to overlap the ischemic penumbra, and may deserve to be a molecular penumbra.
Role of kynurenic acid on vestibulo‐autonomic symptoms following unilateral labyrinthectomy in rats
Authors: Park Byung Rim , Kim Min Sun , Lee Moon Young , Choi Myung Ae , Choi Dong Ok , Doh Nam Yong 
Published: January 2004

AbstractUnilateral labyrinthectomy produces vestibular symptoms that abate over time in a process of behavioral recovery known as vestibular compensation. To investigate the role of glutamate receptors in vestibulo‐autonomic symptoms, we measured spontaneous nystagmus and c‐Fos expression in the medial vestibular nucleus (MVN) and the solitary tract nucleus (STN) in unilateral labyrinthectomized Sprague‐Dawley rats treated with kynurenic acid, a broad spectrum glutamate receptor antagonist, 30 min before labyrinthectomy. Spontaneous nystagmus occurred after unilateral labyrinthectomy (UL), and nystagmus decreased gradually over time. Spatial expression of c‐Fos in the MVN following UL corresponded to disappearance of spontaneous nystagmus. Expression of c‐Fos in the STN decreased 24 h after UL. Pretreatment with kynurenic acid decreased c‐Fos expression in both the MVN and STN and decreased spontaneous nystagmus. These results suggest that pretreatment with kynurenic acid facilitates recovery of autonomic symptoms as well as behavioral response following UL.
Reduction of dynamic LFT systems with LTI model uncertainties
Authors: Ferreres Gilles 
Published: January 2004

AbstractA method was proposed by Becket al. (IEEE Trans Automatic Control, 1996;41: 1466–1477), for reducing an LFT system with linear time varying model uncertainties. This paper extends this method to the case of linear time invariant model uncertainties, by computing on a finite frequency interval frequency‐dependent generalized grammians. The original method by Becket al. is proved to be equivalent to the computation of constant generalized grammians on the infinite frequency interval (−∞,+∞). Copyright © 2004 John Wiley & Sons, Ltd.
Collecting and analyzing qualitative data for system dynamics: methods and models
Authors: Luna‐Reyes Luis Felipe , Andersen Deborah Lines 
Published: January 2004

AbstractSystem dynamics depends heavily upon quantitative data to generate feedback models. Qualitative data and their analysis also have a central role to play at all levels of the modeling process. Although the classic literature on system dynamics strongly supports this argument, the protocols to incorporate this information during the modeling process are not detailed by the most inﬂuential authors. Data‐gathering techniques such as interviews and focus groups, and qualitative data analysis techniques such as grounded theory methodology and ethnographic decision models could have a strong, critical role in rigorous system dynamics efforts. This article describes some of the main qualitative, social science techniques and explores their suitability in the different stages of the modeling process. Additionally, the authors argue that the techniques described in the paper could contribute to the understanding of the modeling process, facilitate communication among modelers and clients, and set up a methodological framework to promote constructive discussion around the merits of qualitative versus quantitative modeling. Copyright © 2003 John Wiley & Sons, Ltd.