bluuebunny/crossref_metadata_2025 huggingface dataset:
Defining pathways of loss and secretion of chemical messengers from astrocytes
Authors: Evanko Daniel S. , Zhang Qi , Zorec Robert , Haydon Philip G.
Published: July 2004

It is becoming evident that glia, and astrocytes in particular, are intimately involved in neuronal signaling. Astrocytic modulation of signaling in neurons appears to be mediated by the release of neuroactive compounds such as the excitatory amino acid glutamate. Release of these transmitters appears to be driven by two different processes: (1) a volume regulatory response triggered by hypo‐osmotic conditions that leads to the release of osmotically active solutes from the cytoplasm into the extracellular space, and (2) intracellular calcium‐dependent vesicle‐mediated excytotic release. The regulatory volume decrease may be mediated by any of several different pathways that increase membrane permeability, thus allowing osmolytes to travel down their concentration gradient into the extracellular space. Such pathways include anion channels, hemichannels, P2X receptor channels, and transporters or multidrug resistance proteins. The excytotic release process may use calcium triggered synaptic like vesicle fusion or alterations in constitutive vesicle trafficking to the membrane. Determining the contribution of any of these release mechanisms requires agents that can be used to specifically block pathways of interest. Currently, many of the pharmacological compounds being used exhibit a great deal of cross‐reactivity between several of these pathways. For example, the popular anion channel inhibitor 5‐nitro‐2‐(3‐phenyl‐propylamino)benzoic acid (NPPB) is an efficient blocker of both hemichannels and vesicle loading. This demonstrates the need to more fully characterize the activities of the agents currently available and to choose pathway blockers carefully when designing experiments. © 2004 Wiley‐Liss, Inc.
D‐Serine as a glial modulator of nerve cells
Authors: Miller Robert F.
Published: July 2004

Until the last decade, it was widely accepted that D‐amino acids had no functional role in higher organisms, but that they were restricted to lower organisms, such as bacteria, where they are integrated into the proteoglycans of the cell wall. However, D‐serine proved to be an effective coagonist at the “glycine‐binding” site of the N‐methyl‐D‐aspartate (NMDA) glutamate receptors, and this observation led to chemical analyses that have now revealed the presence of high levels of D‐serine in the central nervous system, including many regions of the brain and retina. D‐Serine has been localized to astrocytes and can be released by glutamate through stimulation of AMPA receptors. A new enzyme, serine racemase has been localized to glial cells and converts L‐serine to D‐serine. Degradation of D‐serine takes place through D‐amino acid oxidase, an enzyme once thought to metabolize D‐amino acids from external sources. Although the “glycine‐binding” site of NMDA receptors was initially regarded as a saturated site, evidence in many brain regions has established that this site is not saturated and is therefore modulated by interactions between glial cells and neurons. In some, but not all, studies, D‐serine enhances NMDA‐mediated currents; a light‐evoked enhancement to NMDA currents has been reported in the retina. D‐serine also plays a role in synaptic and cellular development, particularly in the cerebellum, where the normal developmental sequences underlying synapse formation onto Purkinje cells and the migration of granule cells are dependent on NMDA receptors during a time when high levels of D‐serine are expressed in the Bergmann glia and other cerebellar astrocytes. D‐serine must be added to the list of agents through which glial cells participate in controlling the excitability of neurons. © 2004 Wiley‐Liss, Inc.
Glial modulation of synaptic transmission at the neuromuscular junction
Authors: Colomar Aurore , Robitaille Richard
Published: July 2004

The neuromuscular junction (NMJ) is a cholinergic synapse that controls muscle contraction. Glial cells, called perisynaptic Schwann cells, surround nerve terminals at the NMJ. Transmitter release induced by repetitive nerve stimulation, elicit a frequency‐dependent activation of G‐protein‐coupled receptors on perisynaptic Schwann cells and the release of calcium from internal stores. In return, perisynaptic Schwann cells modulate synaptic activity during and following high‐frequency stimulation through short‐term plasticity. In the present review, we discuss evidence of glial involvement in the short‐term plasticity at the NMJ and the potential impact of such modulation on synaptic efficacy. © 2004 Wiley‐Liss, Inc.
Enhancement of arsenic trioxide‐mediated apoptosis using docosahexaenoic acid in arsenic trioxide‐resistant solid tumor cells
Authors: Baumgartner Melanie , Sturlan Sanda , Roth Erich , Wessner Barbara , Bachleitner‐Hofmann Thomas
Published: July 2004

It has been shown that the polyunsaturated fatty acid docosahexaenoic acid (DHA) can sensitize various tumor cells to reactive oxygen species (ROS)‐inducing anticancer agents. Recently, we demonstrated that DHA also enhances the apoptotic effect of clinically achievable concentrations (1–2 μM) of arsenic trioxide (As2O3) in several As2O3‐resistant human leukemic cell lines via a ROS‐dependent mechanism. The aim of the present study was to evaluate whether this combined effect of As2O3 and DHA is also applicable to As2O3‐resistant solid tumor cells. We have tested 12 different tumor cell lines, including MDA‐MB‐468, SK‐BR‐3, MCF‐7 (breast cancer), ES‐2, SKOV‐3 (ovarian cancer), HT‐29, SW‐620, LS‐174T (colon cancer), PC‐3 (prostate cancer), HeLa (cervical cancer), PANC‐1 (pancreatic cancer) and one primary melanoma cell line. With the exception of MDA‐MB‐468 and ES‐2, all cells were resistant to treatment with either As2O3 or DHA alone. However, combined treatment with As2O3 and DHA significantly reduced viability in 7 of the 10 As2O3‐resistant solid tumors tested. The cytotoxic effect of As2O3 and DHA was associated with the induction of apoptosis and a concomitant increase of intracellular lipid peroxidation products. Importantly, the combined effect of As2O3 and DHA was selectively toxic for malignant cells since no cytotoxic effect was observed in normal skin fibroblasts, human microvascular endothelial cells and peripheral blood mononuclear cells derived from healthy donors. Our data indicate that DHA may help to extend the therapeutic spectrum of As2O3 in the treatment of solid tumors since it may overcome de novo or acquired resistance to As2O3. © 2004 Wiley‐Liss, Inc.
Global changes in the expression patterns of RNA isolated from the hippocampus and cortex of VX exposed mice
Authors: Blanton Jason L. , D'Ambrozio Jonathan A. , Sistrunk James E. , Midboe Eric G.
Published: July 2004

One of the established activities of the nerve agent VX is inhibition of the enzyme acetylcholinesterase (AChE). This inhibition affects the cholinergic nervous system by decreasing the activity of the neurotransmitter‐hydrolyzing enzyme cholinesterase (ChE). In an effort to gain a more comprehensive understanding of the molecular pathways affected by low‐level exposure to VX, an expression profiling approach was used to identify genes with altered RNA expression patterns after exposure.

Specifically, mice were exposed to 0.1, 0.2, 0.4, and 0.6 LD50 VX for a period of 2 weeks. At 2 h, 72 h, and 2 weeks after the final exposure, RNA was isolated from both the hippocampus and the cortex. Changes in gene expression levels were assessed by DNA microarray technology and grouped according to their expression patterns. Data presented here demonstrate that 2 weeks postexposure all up‐regulated gene expression has returned to pre‐exposure levels, including genes related to the central nervous system. Additionally, this investigation has revealed non‐AChE pathway genes involved in other neuronal functions that display altered expression profiles after VX exposure. © 2004 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:115–123, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20015
Comparison of genomic and cDNA sequences of guinea pig CYP2B18 and rat CYP2B2: Absence of a phenobarbital‐responsive enhancer module in the upstream region of the CYP2B18 gene
Authors: Yamamoto Midori , Mise Masashi , Matsumoto Sanae , Ito Shoich , Gohyama Noriko , Ishida Satoru , Sagara Yasuhiro , Omiecinski Curtis J. , Oguri Kazuta , Yamada Hideyuki
Published: July 2004

Potential mechanisms were investigated whereby CYP2B18, a cytochrome P450 gene exhibiting high constitutive expression but only low levels of phenobarbital‐inducibility in the guinea pig liver, may be differentially regulated versus the highly inducible rat CYP2B2 gene. To comparatively assess potential regulatory sequences associated with CYP2B18, a guinea pig genomic library was screened enabling isolation of the CYP2B18 gene. The genomic screening process resulted in the identification of at least four closely‐related CYP2B18 genes, designated here as CYP2B18A‐D. Of these isolates, CYP2B18A exhibited sequence identical to that of the CYP2B18 cDNA. Further, the deduced amino acid sequence of the CYP2B18 cDNA was identical to that of N‐terminal and internally‐derived peptide sequences obtained in this investigation from CYP2B18 protein isolated from guinea pig liver. Genomic structural sequences were derived for CYP2B18A, together with the respective 5′‐upstream and intronic regions of the gene. Comparison of the CYP2B18A and CYP2B2 gene sequences revealed the lack of repetitive LINE gene sequences in CYP2B18A, putative silencing elements that effect neighboring genes, although these sequences were present in both 5′‐upstream and 3′‐downstream regions of CYP2B2. We determined that the phenobarbital‐responsive enhancer module was absent from the 5′‐upstream region as well as the intronic regions of CYP2B18A gene. We hypothesize that the compromised phenobarbital inducibility of CYP2B18A stems from its lack of a functional phenobarbital responsive enhancer module. © 2004 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:124–130, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20016
Glibenclamide interferes with mitochondrial bioenergetics by inducing changes on membrane ion permeability
Authors: Fernandes Maria A. S. , Santos Maria S. , Moreno António J. M. , Duburs Gunars , Oliveira Catarina R. , Vicente Joaquim A. F.
Published: July 2004

The interference of glibenclamide, an antidiabetic sulfonylurea, with mitochondrial bioenergetics was assessed on mitochondrial ion fluxes (H+, K+, and Cl−) by passive osmotic swelling of rat liver mitochondria in K‐acetate, KNO3, and KCl media, by O2 consumption, and by mitochondrial transmembrane potential (Δψ). Glibenclamide did not permeabilize the inner mitochondrial membrane to H+, but induced permeabilization to Cl− by opening the inner mitochondrial anion channel (IMAC). Cl− influx induced by glibenclamide facilitates K+ entry into mitochondria, thus promoting a net Cl−/K+ cotransport, Δψ dissipation, and stimulation of state 4 respiration rate. It was concluded that glibenclamide interferes with mitochondrial bioenergetics of rat liver by permeabilizing the inner mitochondrial membrane to Cl− and promoting a net Cl−/K+ cotransport inside mitochondria, without significant changes on membrane permeabilization to H+. © 2004 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:162–169, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20022
The physiology of insect auditory afferents
Authors: Mason Andrew C. , Faure Paul A.
Published: July 2004

This review presents an overview of the physiology of primary receptors serving tympanal hearing in insects. Auditory receptor responses vary with frequency, intensity, and temporal characteristics of sound stimuli. Various insect species exploit each of these parameters to differing degrees in the neural coding of auditory information, depending on the nature of the relevant stimuli. Frequency analysis depends on selective tuning in individual auditory receptors. In those insect groups that have individually tuned receptors, differences in physiology are correlated with structural differences among receptors and with the anatomical arrangement of receptors within the ear. Intensity coding is through the rate‐level characteristics of tonically active auditory receptors and through variation in the absolute sensitivities of individual receptors (range fractionation). Temporal features of acoustic stimuli may be copied directly in the timing of afferent responses. Salient signal characteristics may also be represented by variation in the timing of afferent responses on a finer temporal scale, or by the synchrony of responses across a population of receptors. Microsc. Res. Tech. 63:338–350, 2004. © 2004 Wiley‐Liss, Inc.
New unusual miniature‐like wing mutation in Drosophila virilis
Authors: Kozeretska Irina A. , Gubenko Irina S. , Gorb Stanislav N.
Published: July 2004

A new recessive, sex‐linked, nonlethal in the homozygote, wing mutation in Drosophila virilis was studied using a hybridological assay, light microscopy, and transmission electron microscopy. The mutants have abnormally small wings; the phenotype is attributed to a cell‐autonomous reduction in the size of the epidermal cells of the differentiating wing. The phenotype is also characterized by abnormally oriented wing hairs, wavy wing edge, temperature sensitivity, and some abnormalities in the wing veins. J. Morphol. 261:270–275, 2004. © 2004 Wiley‐Liss, Inc.
Basic fibroblast growth factor, neurofilament, and glial fibrillary acidic protein immunoreactivities in the myenteric plexus of the rat esophagus and colon
Authors: Chadi Gerson , Gomide Vânia Canterucci , Rodrigues de Souza Romeu , Scabello Rodrigo Torres , Maurício da Silva César
Published: July 2004

The enteric nervous system consists of a number of interconnected networks of neuronal cell bodies and fibers as well as satellite cells, the enteric glia. Basic fibroblast growth factor (bFGF) is a mitogen for a variety of mesodermal and neuroectodermal‐derived cells and its presence has been described in many tissues. The present work employs immunohistochemistry to analyze neurons and glial cells in the esophageal and colic enteric plexus of the Wistar rat for neurofilament (NF) and glial fibrillary acidic proteins (GFAP) immunoreactivity as well as bFGF immunoreactivity in these cells. Rats were processed for immunohistochemistry; the distal esophagus and colon were opened and their myenteric plexuses were processed as whole‐mount preparations. The membranes were immunostained for visualization of NF, GFAP, and bFGF. NF immunoreactivity was seen in neuronal cell bodies of esophageal and colic enteric ganglia. GFAP‐immunoreactive enteric glial cells and processes were present in the esophageal and colic enteric plexuses surrounding neuronal cell bodies and axons. A dense net of GFAP‐immunoreactive processes was seen in the ganglia and connecting strands of the myenteric plexus. bFGF immunoreactivity was observed in the cytoplasm of the majority of the neurons in the enteric ganglia of esophagus and colon. The two‐color immunoperoxidase and immunofluorescence methods revealed bFGF immunoreactivity also in the nucleus of GFAP‐positive enteric glial cells. The results suggest that immunohistochemical localization of NF and GFAP may be an important tool in the study of the plasticity in the enteric nervous system. The presence of bFGF in neurons and glia of the myenteric plexus of the esophagus and the colon indicates that this neurotrophic factor may exert autocrine and paracrine actions in the enteric nervous system. J. Morphol. 261:323–333, 2004. © 2004 Wiley‐Liss, Inc.
Fine structure and immunocytochemistry of monotreme hairs, with emphasis on the inner root sheath and trichohyalin‐based cornification during hair evolution
Authors: Alibardi Lorenzo
Published: July 2004

The fine structure of hairs in the most ancient extant mammals, the monotremes, is not known. The present study analyzes the ultrastructure and immunocytochemistry for keratins, trichohyalin, and transglutaminase in monotreme hairs and compares their distribution with that present in hairs of the other mammals. The overall ultrastructure of the hair and the distribution of keratins is similar to that of marsupial and placental hairs. Acidic and basic keratins mostly localize in the outer root sheath. The inner root sheath (IRS) comprises 4–8 cell layers in most hairs and forms a tile‐like sheath around the hair shaft. No cytological distinction between the Henle and Huxley layers is seen as cells become cornified about at the same time. Externally to the last cornified IRS cells (homologous to the Henle layer), the companion layer contains numerous bundles of keratin. Occasionally, some granules in the companion layer show immunoreactivity for the trichohyalin antibody. This further suggests that the IRS in monotremes is ill‐defined, as the companion layer of placental hairs studied so far does not express trichohyalin. A cross‐reactivity with an antibody against sheep trichohyalin is present in the IRS of monotremes, suggesting conserved epitopes across mammalian trichohyalin. Trichohyalin granules in the IRS consist of a framework of immunolabeled coarse filaments of 10–12 nm. The latter assume a parallel orientation and lose the immunoreactivity in fully cornified cells. Transglutaminase immunolabeling is diffuse among trichohyalin granules and among the parallel 10–12 nm filaments of maturing inner root cells. Transglutaminase is present where its substrate, trichohyalin, is modified as matrix protein. Cornification of IRS is different from that of hair fiber cuticle and from that of the cornified layer of the epidermis above the follicle. The different consistency among cuticle, IRS, and corneous layer of the epidermis determines separation between hair fiber, IRS, and epidermis. This allows the hair to exit on the epidermal surface after shedding from the IRS and epidermis. Based on comparative studies of reptilian and mammalian skin, a speculative hypothesis on the evolution of the IRS and hairs from the skin of synapsid reptiles is presented. J. Morphol. 261:345–363, 2004. © 2004 Wiley‐Liss, Inc.
Evolutionary transformation from muscular to hydraulic movements in spider (Arachnida, Araneae) genitalia: A study based on histological serial sections
Authors: Huber Bernhard A.
Published: July 2004

The male genitalia of 107 spider species representing 73 families were serially sectioned and studied with an emphasis on muscles moving the genital bulb. As a rule, most non‐Entelegynae have two bulbal muscles, most Entelegyne have none, but many exceptions occur. Variation also occurs with regard to origin and attachment of bulbal muscles. There appears to be a trend towards a shift of the origin from proximal (Liphistius, Atypus) to more distal palpal segments (Haplogynae). In most Entelegynae the muscular movement is replaced by hydraulic movement caused by expanding membranes (hematodochae). Hematodochae probably permit increased bulbal rotation and movements of higher complexity. New evidence is presented arguing against Palpimanidae being representatives of Entelegynae. Bulbal glands other than those discharging into the sperm duct (previously known in Amaurobiidae and Dictynidae only) are described in several entelegyne families. J. Morphol. 261:364–376, 2004. © 2004 Wiley‐Liss, Inc.
Synthesis of Chlorotitanium(IV) Schiff‐Base Complexes and their Application to Styrene Polymerization
Authors: Kim Il , Ha Yun Sun , Zhang Dan Feng , Ha Chang‐Sik , Lee Uk
Published: July 2004

Summary: A [TiCl2(salen)] complex and its derivatives with the formula [TiCl2(L)] [L = salen(tBu), salen(di‐Me), salen(di‐tBu), salen(Me)] were synthesized in high yield by reacting the Schiff‐base ligands with TiCl4. [TiCl2{salen(tBu)}] and [TiCl2{salen(di‐tBu)}] have been characterized by single‐crystal X‐ray diffraction. Styrene polymerizations carried out with [TiCl2(salen)] and its derivatives co‐catalyzed by MAO yielded syndiotactic polystyrenes. The catalytic activity and syndiospecificity were dependent on the bulkiness of the ortho substituents in the aryl ring of ligand.

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Cu Crystal Growth on a Chelating Fiber with Different Amine Chain Lengths
Authors: Ko Young Gun , Shin Dong Hun , Choi Ung Su
Published: July 2004

Summary: Poly(acryloamidino ethyleneamine) (PAEA) and poly(acryloamidino diethylene diamine) (PADD) have been synthesized for the observation of CuII complex and Cu(OH)2 crystal‐growth on the surface of different numbers of amino groups immobilized on polyacrylonitrile (PAN) fibers. The shape of CuII crystal growth depends on the amine chain length of the chelating fiber; Cu(OH)2 crystals grow on the surface of the chelating fiber after CuII adsorption.

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POCA: pattern‐oriented channel assignment scheme for wireless cellular networks
Authors: Ahmed Rana Ejaz , Cardan Robin
Published: July 2004

This paper presents a new decentralized dynamic channel allocation scheme which uses a ‘clustering’ concept to allocate channels efficiently. Simulation results show that the proposed scheme performs better than fixed channel assignment and some other dynamic channel allocation schemes under low and moderate traffic load conditions. Copyright © 2004 John Wiley & Sons, Ltd.
Frame‐level performance measurement in an ATM test‐bed environment: methodologies and experiences
Authors: Ahmed Rana E. , Khan Hasan A. , Mouftah Hussein T.
Published: July 2004

Performance testing is related to user‐perceived performance of asynchronous transfer mode (ATM) technology. We describe the test methodologies used to measure various frame‐level quality of service metrics, such as throughput and latency. Some practical issues encountered in performance testing in an ATM test‐bed environment are addressed. Copyright © 2004 John Wiley & Sons, Ltd.
Early‐onset gastric carcinomas display molecular characteristics distinct from gastric carcinomas occurring at a later age
Authors: Carvalho Ralph , Milne Anya NA , van Rees Bastiaan P , Caspers Eric , Cirnes Luís , Figueiredo Céu , Offerhaus G Johan A , Weterman Marian AJ
Published: July 2004

Gastric cancer is thought to result from a combination of environmental factors and accumulation of specific genetic alterations, and consequently mainly affects older patients (>50 years of age). Fewer than 10% of patients present with the disease before 45 years of age and these young patients are thought to develop carcinomas with a different molecular genetic profile from that of sporadic carcinomas occurring at a later age. Forty early‐onset gastric carcinoma resection specimens were characterized for microsatellite instability (MSI) and loss of heterozygosity status using 22 polymorphic microsatellite markers. Twenty‐four biopsies were additionally evaluated for the presence of MSI. No MSI was observed in any of the cases analysed. Losses were infrequent, but were most common for the D1S234 (26.1%) and D1S1676 (17.4%) markers, flanking the RUNX3 gene; for the p53ALU (23.1%) and TP53 (15.4%) markers, near the TP53 gene; and for the D16S2624 (17.2%) marker, near the E‐cadherin (CDH1) gene. All cases with loss of CDH1, as well as 6/7 cases with loss of TP53, displayed aberrant staining of the corresponding proteins, pointing to a functional role for these proteins in early‐onset gastric carcinogenesis. No germline CDH1, TP53 or RUNX3 mutations were detected in any of the cases analysed. No correlation was observed between non‐functional E‐cadherin and the histological type of the tumours analysed. Finally, Epstein–Barr virus was not detected in any of the cases analysed. On the basis of these results, early‐onset gastric carcinomas appear to have characteristics distinct from gastric carcinomas occurring at a later age. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Structural and energetic characterization of nucleic acid‐binding to the fingers domain of Moloney murine leukemia virus reverse transcriptase
Authors: Crowther Robert L. , Remeta David P. , Minetti Conceição A.S.A. , Das Debanu , Montano Sherwin P. , Georgiadis Millie M.
Published: July 2004

Reverse transcriptase is an essential retroviral enzyme that replicates the single‐stranded RNA genome of the retrovirus producing a double‐stranded DNA copy, which is subsequently integrated into the host's genome. We have previously reported that processive DNA synthesis of Moloney murine leukemia virus reverse transcriptase (MMLV RT) is severely compromised by substitution of an Ala for the fingers domain residue Arg 116. In order to further investigate the role of Arg 116 in interactions of MMLV RT with nucleic acids, we have determined the crystal structure of the R116A N‐terminal fragment and characterized the binding of two self‐complementary DNA duplexes [d(CATGCATG)2 and d(CGCGCGCG)2] to both the wild‐type and R116A fragments by isothermal titration calorimetry. The resultant thermodynamic profiles extrapolated to 25°C reveal that binding of the wild‐type N‐terminal fragment to both DNA duplexes is enthalpy‐driven and characterized by an unfavorable entropy. Although the temperature dependence of the respective protein–DNA binding enthalpies is markedly different reflecting distinct heat capacity changes, the binding free energies are nearly identical and relatively invariant to temperature (ΔG ∼ −6.0 kcal · mol−1). In contrast to the wild‐type fragment, the R116A fragment exhibits no measurable affinity for either DNA duplex, yet its crystal structure reveals no significant changes when compared to the wild‐type structures. We suggest that hydrogen‐bonding interactions involving the fingers domain residue Arg 116 are critical for DNA binding as well as processive DNA synthesis by MMLV RT. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Kinetics of interaction of three carbamate pesticides with Indian soils: Aligarh district
Authors: Bansal OP
Published: July 2004

The kinetics of interaction with soil of three carbamate pesticides (I, II, III) used as nematicides and herbicides was studied at four different temperatures from solutions of six soil samples of Aligarh district. The values obtained for rate constants for adsorption and desorption were in good agreement with those obtained from the Lindstrom model, which proved useful in the simultaneous evaluation of adsorption (k1) and desorption (k2) rate constants. The rate constants for pesticides were in the order III > I > II on all the six soil samples. The data for rate constants, activation energies, heats of activation, entropy of activation and thermodynamic parameters indicated a partly physical and partly chemical adsorption of pesticide on the soil surfaces. Adsorption occurred via coordination and/or protonation of the exchangeable cations with the amidic carbonyl group, and hydrogen bonding and dipole association at the crystal edge and basal surfaces. The adsorptivity of the soils may be attributed to the organic matter content and percentage clay content. Copyright © 2004 Society of Chemical Industry
STM study of large organic molecules adsorption on Si(100)‐2 × 1
Authors: Rada Tomás , Chen Qiao , Richardson Neville
Published: July 2004

The adsorption of large organic molecules, including tetracene and perylene, on clean Si(100) is followed by scanning tunnelling microscopy (STM) in an ultra high vacuum environment. Different adsorption sites have been observed for these organic molecules. Two types of tetracene adsorption are indicated by filled state images but three types can be distinguished in empty state images. Molecules aligned both along and perpendicular to the silicon dimer rows can be observed. Measurements of the length of this molecule in all configurations indicate that the molecule stays intact during the adsorption process. High resolution of STM images reveal that the perylene molecules bond to the substrate in a vertical orientation and forming packs of perylene aligned perpendicular to the silicon dimmer rows. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Donor‐related photoionization cross‐section of GaAs–(Ga, Al)As quantum dots: hydrostatic pressure effects
Authors: Correa J. D. , Porras‐Montenegro N. , Duque C. A.
Published: July 2004

Using a variational method and the effective‐mass approximation, we calculated the binding energy for shallow‐donor impurities in spherical GaAs–(Ga, Al)As quantum dots. In this paper we present results for different dimensions of the structure and radial impurity positions. Calculations include the hydrostatic pressure effects. We discuss the hydrostatic pressure dependence on the binding energy and the photoionization cross‐section. The measurement of photoionization in such systems would be of great interest in understanding the optical properties of carriers in quantum dots. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Finite‐Elemente‐Berechnungen zum Trag‐ und Verformungsverhalten von Kopfbolzendübeln
Authors: Hegger Josef , Goralski Claus , Rauscher Sabine , Kerkeni Naceur
Published: July 2004

Die Verbundfuge zwischen Betongurt und Stahlträger wird bei der numerischen Simulation von Verbundträgern durch Federn oder Interface‐Elemente mit bi‐ oder trilinearen Schubkraft‐Schlupfgesetzen abgebildet. Mit diesen in der Praxis bewährten Methoden läßt sich das globale Tragverhalten für beliebige Verdübelungsgrade berechnen. Zur Abbildung einer konzentrierten Lasteinleitung, z. B. bei Verankerungen, ist jedoch eine dreidimensionale Modellierung des Verbundmittels erforderlich. Der Aufsatz beschreibt ein dreidimensionales, nichtlineares Finite‐Elemente‐Modell, mit dem das lokale Trag‐ und Verformungsverhalten von Kopfbolzendübeln unter Abscherbeanspruchung bestimmt werden kann. Zur Kalibrierung des Modells dienten eigene Abscherversuche für Einzeldübel. In Parameterstudien wird der Einfluß der Betonfestigkeit, der Schaftlänge und der Schweißwulstgeometrie untersucht. Gleichzeitig werden die Grenzen in der Simulation von Abscherversuchen mit der Finiten‐Elemente‐Methode aufgezeigt.
Ermittlung von Eigenwerten und Eigenformen für Stäbe und Stabwerke
Authors: Kindmann Rolf , Laumann Jörg
Published: July 2004

Für die Bemessung stabilitätsgefährdeter Stäbe und Stabwerke hat die Ermittlung von Eigenwerten und Eigenformen zentrale Bedeutung. Da aus der Literatur zahlreiche, z. T. stark unterschiedliche Berechnungsverfahren bekannt sind, wird die Frage geklärt, welche Verfahren aufgrund der spezifischen Problemstellung am besten geeignet sind. Mit einem modifizierten Vektoriterationsverfahren und einem speziell angepaßten Matrizenzerlegungsverfahren wird auf zwei Methoden detailliert eingegangen. Darüber hinaus wird die Ermittlung von Eigenwerten und Eigenformen mit Hilfe von EDV‐Programmen und die Beurteilung ihrer Ergebnisse erläutert.
A new modelling technique using a subsystem for structural schematic design of tall buildings
Authors: Kim Hansoo , Jung Jonghyun , Cho Sukhee
Published: July 2004

In the schematic design of a tall building structure, a structural designer builds structural analysis models for many schemes. However, conventional modelling techniques force the designer to view the scheme as an assembly of many members related in a complicated manner. Therefore, the modelling scheme is laborious, prone to error and time‐consuming. In this study, we present a new modelling technique that uses a subsystem—that is, the assembly of the members participated in a specific type of load transfer—as the primary modelling unit. We expect this modelling technique to allow simple modelling of a scheme. Copyright © 2004 John Wiley & Sons, Ltd.
Neuropathological consequences of prenatal cocaine exposure in the mouse
Authors: Ren Jia‐Qian , Malanga C.J. , Tabit Eddy , Kosofsky Barry E.
Published: July 2004

We have developed an animal model in Swiss Webster mice to identify mechanisms by which prenatal exposure to cocaine results in persistent alterations in brain structure and function. Clinical data suggests that children who demonstrate the largest impairments in prenatal brain growth, which are positively correlated with the highest level of prenatal cocaine exposure, are more likely to demonstrate selective impairment in postnatal brain growth, as well as postnatal impairments in motor function, attention and language skills. We conducted neuroanatomic studies to identify the postnatal evolution of structural changes in the primary somatosensory (SI) cortex of the developing mouse brain following prenatal exposure to cocaine. Our previous work, and that of others, provides evidence that many of the processes underlying corticogenesis are disrupted by gestational exposure of the developing mouse brain to cocaine, and that from the earliest phases of corticogenesis that there is an imprecision in the development of cortical lamination. We performed morphometric comparisons between the brains of animals prenatally exposed to varying amounts of cocaine with vehicle and malnutrition controls on postnatal (P) days P9 and P50. We found that on P50, but not P9, the relative number of cortical neurons in S1 is significantly less in cocaine exposed animals as compared with controls. The significant decrease in the number of cells in cocaine exposed animals on P50 is evident as a decreased density of cells restricted to the infragranular compartment (layers V and VI). Those changes are not seen in malnourished animals.

Taken together our findings support the conclusion that cocaine‐induced alterations in SI cortical cytoarchitectonics are in part a consequence of altered postnatal survival of infragranular cortical neurons, which are lost during the interval between P9 and P50. Determining whether a similar process is evident in a subset of humans following in utero cocaine exposure is a high priority for future clinical brain imaging studies, because analogous structural changes could impact the brain function and behavioral repertoire of infants and children following significant prenatal exposures.
Maternal administration of thalidomide or valproic acid causes abnormal serotonergic neurons in the offspring: implication for pathogenesis of autism
Authors: Miyazaki Kaoru , Narita Naoko , Narita Masaaki
Published: July 2004

Embryonic exposure to thalidomide (THAL) or valproic acid (VPA) before neural tube closure has been demonstrated as a useful model for human autism in rats. Abnormalities of the serotonergic system which are often observed in human autism have been shown in these rats. Thus, we examined whether early serotonergic neuronal development is perturbed by THAL/VPA. When pregnant rats were exposed to THAL or VPA on embryonic day 9, a dramatic shift of the distribution of serotonergic neurons in the dorsal raphe nucleus was observed on postnatal day 50. This alteration is thought to reflect abnormality of serotonergic neuronal differentiation and migration. In vitro studies revealed that VPA retards the maturation of serotonergic neuron from ES cell‐derived neuronal progenitors, whereas exogenously added Sonic hedgehog, a morphogen that has been implicated in serotonergic cell fate, partially prevented this retardation. These results indicate that disruption of early serotonergic neuronal development might be involved in the etiology of autism.
Surgery of the Hand in Severe Systemic Sclerosis
Authors: GILBART M. K. , JOLLES B. M. , LEE P. , BOGOCH E. R.
Published: July 2004

Ten patients with scleroderma and severe hand problems required surgery, and seven were available for follow-up (two died from scleroderma-related complications and one was lost to follow-up). The mean duration of follow-up was 4 (range 1.5–9) years. Thirty-three procedures were carried out, including five metacarpophalangeal joint exisional arthroplasties, 13 proximal interphalangeal joint fusions, ten distal interphalangeal joint fusions, and one thumb interphalangeal joint fusion. The metacarpophalangeal joint excision arthroplasties and proximal interphalangeal joint fusions were performed for the correction of severe fixed “finger-in-palm” deformities. Lesions of cutaneous calcinosis were removed in four patients.

Fixation was satisfactory in all cases of interphalangeal joint fusion, with no cases of non-union. Wound healing was satisfactory in six of seven patients. A second surgical procedure was required in three patients for the removal of tension band wires following interphalangeal fusion. Calcinosis was effectively removed using a high-speed dental burr. The results of hand surgery for systemic sclerosis are reliable, but goals must be limited and patient expectations should be modest.
Expression of bone morphogenetic proteins, receptors, and tissue inhibitors in human fetal, adult, and osteoarthritic articular cartilage
Authors: Chen Andrew L. , Fang Carrie , Liu Chuanju , Leslie Michael P. , Chang Eric , Di Cesare Paul E.
Published: July 2004

Coordinate expression of BMPs and their receptors and inhibitors is likely necessary for physiologic BMP regulation and activity. To characterize the expression of such factors in fetal, normal adult, and end‐stage osteoarthritic articular cartilage, samples from these sources were analyzed. PCR‐amplified sequences (BMPs 1–11), receptors (IA, IB, II), TGF‐β1, TGF‐β2, inhibitors noggin and follistatin, CDMP‐1, COMP, and GAPDH from cDNAs generated from extracted total RNA were resolved by gel electrophoresis. Protein levels of BMPs 3, 7, and 8 were also analyzed by SDS‐PAGE and Western blotting. RT‐PCR revealed that BMPs 1, 2, 4–6, and 11, BMPR‐IA and II, noggin, follistatin, CDMP‐1, COMP, and GAPDH mRNAs were expressed in similar fashion in both fetal and adult (normal or osteoarthritic) cartilage. BMPs 9 and 10 mRNAs were not expressed in either group. BMPs 7, 8, and BMPR‐IB mRNAs were consistently expressed in fetal but not in adult cartilage. BMP‐3 mRNA was expressed in fetal and normal adult, but not in osteoarthritic samples. TGF‐β1 was expressed in both adult normal and osteoarthritic, but not fetal, samples. Similarly, Western blotting demonstrated BMPs 7 and 8 to be present in fetal but not in adult samples. BMP‐3 protein was present in fetal and adult normal samples, to a lesser extent, but absent in osteoarthritic cartilage. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
IMPLICATION IN FACT AS AN INSTANCE OF CONTRACTUAL INTERPRETATION
Authors: Kramer Adam
Published: July 2004

This article seeks to analyse the part of interpreting contractual documents that deals with supplementing the (linguistically encoded part of the) contract, and it is argued that the implication of terms in fact is an instance of this interpretation by supplementation. A reason for the strictness of the implication in fact test, as contrasted with the basic objective test of interpretation, is proposed: some information (new terms) is more primary than other information (details added to existing terms), and such primary information is less likely to be intended to go without saying by the contractors. As a result, although implication in fact should be seen as an instance of interpretation, interpretation through supplementation should take account of the primariness of the information by which the contract is being supplemented. To put things another way, the strict officious bystander and business efficacy tests of implication should be seen as at the strict extreme of a continuum of tests of interpretation by supplementation.
A TEMPEST IN A TEAPOT? NINETEENTH-CENTURY CONTESTS FOR LAND IN SOUTH AFRICA'S CALEDON VALLEY AND THE INVENTION OF THE MFECANE
Authors: ETHERINGTON NORMAN
Published: July 2004

The unresolved debate on the mfecane in southern African history has been marked by general acceptance of the proposition that large-scale loss of life and disruption of settled society was experienced across the whole region. Attempts to quantify either the violence or mortality have been stymied by a lack of evidence. What apparently reliable evidence does exist describes small districts, most notably the Caledon Valley. In contrast to Julian Cobbing, who called the mfecane an alibi for colonial-sponsored violence, this article argues that much documentation of conflict in the Caledon region consisted of various ‘alibis’ for African land seizures and claims in the 1840s and 1850s.
KEEPING THE CITY TOTALLY CLEAN: YELLOW FEVER AND THE POLITICS OF PREVENTION IN COLONIAL SAINT-LOUIS-DU-SÉNÉGAL, 1850–1914
Authors: NGALAMULUME KALALA
Published: July 2004

This article explores the ways in which French colonial authorities met the life and death challenge represented by the re-emergence of yellow fever epidemics in Saint-Louis-du-Sénégal at a time when physicians knew very little about the etiology, diagnosis, transmission and treatment of most infectious and parasitic diseases. The discussion focuses on changing strategies and policies designed to address yellow fever threats, the attitudes and priorities of the authorities, the limits of ‘colonial medicine’ and the responses of people affected by sanitary measures. The article argues that because of the ignorance of the etiology and epidemiology of yellow fever, policies were misdirected and did not achieve their primary goals. Even after the introduction of germ theory, the gap between medical thinking and practice persisted for another decade. The African urban working class and underclass were the first victims of this state of affairs. The article also examines the conflict between the interests of public health, commerce and privacy rights.
‘Unbounded Visions’: Boulez, Mallarmé and Modern Classicism
Authors: WHITTALL ARNOLD
Published: July 2004

Pli selon pli is Boulez’s richest encounter with Mallarmé. As a ‘portrait’ of the poet which sets three of his sonnets, it can be associated not only with other composers – Ravel, Debussy – who set Mallarmé, but also with the poet’s own views on music, and his radical yet tradition-conscious formal practices. Structural and poetic aspects of the fourth movement of the work, ‘Improvisation III’, are examined in detail, highlighting Boulez’s increasing concern with matters of formal coherence. This suggests a strengthening resistance to modernism as fragmentation and the embrace of a modern classicism which shuns the fixed hierarchies of tonal classicism as well as the parodistic juxtapositions of neoclassicism. At the same time, however, the multiple resonances on which modern classicism depends for its coherence ensure that certain aspects of Mallarmé-inspired narrative – concerning shipwrecks and sirens, among other things – cannot be entirely suppressed in present-day critical commentary.
Thermodynamic Structure of Nonlinear Macrokinetics in Reaction-Diffusion Systems
Authors: Sieniutycz Stanisław
Published: July 2004

Affinity picture — new for transport phenomena — and the traditional Onsagerian picture are shown to constitute two equivalent representations for kinetics of chemical reactions and transfer processes. Two competing directions in elementary chemical or transport steps are analyzed. Nonequilibrium systems are described by equations of nonlinear kinetics of Marcelin-Kohnstamm-de Donder type that contain terms exponential with respect to the Planck potentials and temperature reciprocal. Simultaneously these equations are analytical expressions characterizing the transport of the substance or energy through the energy barrier. We regard kinetics of this sort as potential representations of a generalized law of mass action that includes the effect of transfer phenomena and external fields. We also consider physical consequences of these kinetics closely and far from equilibrium, and show how diverse processes can be described. In these developments we point out the significance of nonlinear symmetries and generalized affinity. Correspondence with the Onsager's theory is shown in the vicinity of thermodynamic equilibrium. Yet, the theory shows that far from equilibrium the rates of transport processes and chemical reactions cannot be determined uniquely in terms of their affinities because these rates depend on all state coordinates of the system.
Gammatella: Visualizing Program-Execution Data for Deployed Software
Authors: Jones James A. , Orso Alessandro , Harrold Mary Jean
Published: July 2004

Software systems are often released with missing functionality, errors, or incompatibilities that may result in failures in the field, inferior performances, or, more generally, user dissatisfaction. In previous work, some of the authors presented the gamma approach, whose goal is to improve software quality by augmenting software-engineering tasks with dynamic information collected from deployed software. The gamma approach enables analyses that (1) rely on actual field data instead of synthetic in-house data and (2) leverage the vast and heterogeneous resources of an entire user community instead of limited, and often homogeneous, in-house resources. When monitoring a large number of deployed instances of a software product, however, a significant amount of data is collected. Such raw data are useless in the absence of suitable datamining and visualization techniques that support exploration and understanding of the data. In this paper, we present a new technique for collecting, storing, and visualizing program-execution data gathered from deployed instances of a software product. We also present a prototype toolset, Gammatella, that implements the technique. Finally, we show how the visualization capabilities of Gammatella facilitate effective investigation of several kinds of execution-related information in an interactive fashion, and discuss our initial experience with a semi-public display of Gammatella.
Graph Visualization for the Analysis of the Structure and Dynamics of Extreme-Scale Supercomputers
Authors: Summers Kenneth L. , Caudell Thomas Preston , Berkbigler Kathryn , Bush Brian , Davis Kei , Smith Steve
Published: July 2004

We are exploring the development and application of information visualization techniques for the analysis of new massively parallel supercomputer architectures. Modern supercomputers typically comprise very large clusters of commodity SMPs interconnected by possibly dense and often non-standard networks. The scale, complexity, and inherent non-locality of the structure and dynamics of this hardware, and the operating systems and applications distributed over them, challenge traditional analysis methods. As part of the á la carte (A Los Alamos Computer Architecture Toolkit for Extreme-Scale Architecture Simulation) team at Los Alamos National Laboratory, who are simulating these new architectures, we are exploring advanced visualization techniques and creating tools to enhance analysis of these simulations with intuitive three-dimensional representations and interfaces. This work complements existing and emerging algorithmic analysis tools. In this paper, we give background on the problem domain, a description of a prototypical computer architecture of interest (on the order of 10,000 processors connected by a quaternary fat-tree communications network), and a presentation of three classes of visualizations that clearly display the switching fabric and the flow of information in the interconnecting network.