bluuebunny/crossref_metadata_2025 huggingface dataset:
Short‐ and long‐term effects of treatment of chronic hepatitis B and delta virus by IFN
Authors: Örmeci Necati
Published: November 2003

Chronic hepatitis B virus (HBV) infection is a common infectious disease in the world. Two percent of the patients with chronic HBV infection will develop cirrhosis each year, and will die prematurely from cirrhosis or hepatocellular carcinoma. So far interferon alfa and lamivudine are the only effective drugs. Interferon alfa can be used at the dosage of 9–10 million units thrice a week for 4–6 months either intramuscularly or subcutaneously for standard treatment. Interferon provides sustained response in 1/3 of the patients when HBe Ag is (+). Response rate to interferon therapy in HBe Ag(−) patients was similar to that reported in HBe Ag(+) ones. However the responses were not sustained in many patients, serum HBV‐DNA reappear in most after stopping the treatment. Extension of therapy to 1 year may be needed in patients who are unresponsive to therapy and having HBV‐DNA levels <10 pg/ml and ALT >100 IU. Establishment of unresponsiveness in early phases of the therapy is important and careful follow up of serum HBe Ag may be helpful. Interferon alfa treatment of chronic HDV infection may result in temporary normalization of ALT values. Disappearance of HBV‐DNA and HBs Ag from the serum upon completion of therapy dictates sustained response in chronic HDV infection. The long term effect of interferon with respect to virological and histopathological responses is poor in HDV infection and longer periods of therapy in higher doses may be beneficial.
Vasorelaxant effects of grape polyphenols in rat isolated aorta. Possible involvement of a purinergic pathway
Authors: Mendes Anne , Desgranges Claude , Chèze Catherine , Vercauteren Joseph , Freslon Jean‐Louis
Published: November 2003

The purpose of this study was to investigate the mechanism of the vascular relaxation produced by polyphenolic substances from red wine, with a particular focus on the possible involvement of purinoceptors. With this aim, relaxing responses induced by procyanidin from grape seeds (GSP), anthocyanins, catechin and epicatechin were assessed in rat isolated aortic rings left intact (+E) or endothelium‐denuded (−E). In preparations precontracted with noradrenaline, incubation with NG‐nitro‐l‐arginine methyl ester (100 μm, 30 min) fully inhibited the GSP‐induced relaxations. Concentration–effect curves to these substances (from 10−7 to 10−1 g/L) were determined in depolarized (60 mm KCl) preparations in control condition, after incubation with reactive blue 2 (an antagonist of P2Y purinoceptors, 30 μm), with apyrase (an enzyme which hydrolyses ATP and ADP, 0.8 U/mL) or with α,β‐methylene ATP (an inhibitor of ecto ATPases, 10 μm). In (+E) rings, relaxations (expressed as percentage of initial contraction) were 41 ± 2 and 37 ± 3 for GSP and anthocyanins, respectively. Only modest relaxations (ca. 10%) were observed in (−E) rings, as it was the case for catechin and epicatechin in (±E) rings. Reactive blue 2 or apyrase inhibited the GSP‐ and anthocyanin‐induced relaxations in (+E) rings, while α,β‐methylene ATP shifted to the left the relaxation curves obtained with GSP. These data confirm that modest relaxations observed with catechin and epicatechin are not endothelium‐dependent but that GSP and anthocyanins induce a relaxing effect, which is related to the integrity of the endothelium and the synthesis and release of nitric oxide (NO). Furthermore, the inhibition by apyrase and the increase by ecto‐ATPase inhibition of the GSP‐ and anthocyanin‐induced relaxation suggest that these substances could act via an initial release of nucleotides, which in turn could activate P2Y1 and/or P2Y2 purinoceptors of endothelial cells, trigger the synthesis and release of NO and then lead to relaxation.
Photoelastic Investigation of Bimaterial Interfacial Stresses Induced by Thermal Loading
Authors: Wang W.‐C. , Lin J.‐C.
Published: November 2003

Abstract:  In this paper, the photoelastic technique and finite element method were employed to investigate the interfacial stresses induced by thermal loading in bimaterial structures. By observing the photoelastic fringe patterns, in comparison with those theories developed by other investigators, severe temperature and stress gradients were found across the specimens’ heights. The maximum fringe order near the interface was six times that near the top surface of the photoelastic material when the temperature was raised to 65 °C. Furthermore, for the bimaterial structures, differences were found between measured stress fields as a result of increasing and decreasing temperature differences.
Entrepreneurial Founder Teams: Factors Associated with Member Entry and Exit
Authors: Ucbasaran Deniz , Lockett Andy , Wright Mike , Westhead Paul
Published: November 2003

This exploratory study provides a review of the neglected area of entrepreneurial founder team turnover. A novel distinction is made between entrepreneurial founder team member entry and team member exit. Ninety owner–managed ventures were monitored between 1990 and 2000. Presented hypotheses relating to a team's human capital were explored using multivariate logistic regression analysis. Variables associated with entry were found not to be the same as those associated with exit. The size of the founding team was significantly negatively associated with subsequent team member entry. The link between team turnover and entrepreneurial team heterogeneity was mixed. Functional heterogeneity was weakly significantly positively associated with team member entry. Heterogeneity of prior entrepreneurial experience was significantly positively associated with team member exit. In addition, family firms were significantly negatively associated with team member exit. The average age of the team was not significantly associated with team member entry or exit. Additional insights in future research may be gathered if a broader definition of team turnover (i.e., considering team member entry and exit) is considered. Practitioner awareness of the different factors associated with team member entry and exit may encourage them to provide assistance, which facilitates the team building process over time in developing firms. Promising areas for additional research are highlighted.
The Influence of Diazepam on Atropine Reversal of Behavioural Impairment in Dichlorvos‐Treated Rats
Authors: Savi Miroslav M. , Obradovi Dragan I. , Ugrešić Nenad D. , Bokonji Dubravko R.
Published: November 2003

Abstract: Acute effects on the behaviour of the organophosphate insecticide dichlorvos and its standard antidotes possessing behavioural activity, atropine and diazepam, were studied separately and in combinations in male Wistar rats. In the spontaneous locomotor activity test, dichlorvos and diazepam decreased, whereas atropine increased performance. The effect of dichlorvos was obtained at a dose (5 mg/kg) that induced overt intoxication, and could not be reversed during first half hour‐period after administration of any combination of drugs. In the other two tests, active avoidance learning and rotarod performance, the effective dose of dichlorvos (2 mg/kg) was devoid of somatic signs of intoxication. In these more sensitive tests, the effective atropine dose (40 mg/kg) completely reversed dichlorvos‐induced incapacitation. In the rotarod test, diazepam (0.5 mg/kg) contributed to the incapacitating effect of dichlorvos, and impeded desirable influence of atropine as well. In the active avoidance test, diazepam (2.5 mg/kg) contributed to failure to escape; it did not influence the dichlorvos‐induced decrease of avoidance performance, nor did it impair the completely reversing effects of atropine. The results point to the possible summation of acute incapacitating effects of organophosphates and diazepam on motor performance, which seems to be, at least partly, antagonized by sufficiently high doses of atropine. However, taking into account the long‐term neuroprotective role of the anticonvulsant diazepam, and hence its delayed beneficial influences on behaviour, the immediate testing of atropine/diazepam treatment of organophosphate intoxication in active avoidance paradigm could possess beside sensitivity the predictive value as well.
Evaluation of the Potential Protective Effect of 21‐Aminosteroid U‐74389G on Liver Injury Induced by Reduced and Prolonged Partial Hepatic Ischaemia Reperfusion in Rats
Authors: Zumbado Manuel , Domínguez‐Díez Agustín , Hernández Juan Ramón , Díaz José María , Palomar Rosa , García‐Plaza Guillermo , Navarro Domingo , Boada Luis D.
Published: November 2003

Abstract: The protective effect of the 21‐aminosteroid U‐74389G was studied in an experimental model of partial ischaemia reperfusion liver injury. Previous studies have proven the remarkable potency of 21‐aminosteroids to prevent oxidant‐induced cell injury in vitro and in vivo. However, the capability of these compounds to limit oxidative injury in clinical trials has been considered to be less certain. The potential protective effect exerted by U‐74389G on reduced and prolonged models of ischaemia reperfusion liver injury was studied in male rats subjected to 75 min. of segmentary hepatic ischaemia followed by 1 or 24 hr of reperfusion. Liver injury was evaluated by measuring serum levels of liver enzymes and by histopathological studies. The oxidative status of liver cells was measured by evaluating the levels of liver lipid peroxidation products such as malondialdehyde and the levels of reduced glutathione. Our results lead us to think that treatment with U‐74389G (6 mg/kg) does not bring about any protective effect neither in the levels of transaminases nor in the percentage of hepatocellular necrosis and cellular infiltration observed in any reperfusion‐period groups. In fact and in contrast with our expectations, U‐74389G seemed to increase enzyme release. Furthermore, at the dose used, this 21‐aminosteroid is not capable of inhibiting the lipoperoxidation processes, although it induced an important increase of GSH levels at any time‐period of reperfusion. This last finding seem to suggest that U‐74389G could increase the resistance to oxidant‐induced liver tissue damage. However, our results show that, at the dose used, this compound did not exert any protective effect on liver tissue, thus explaining, at least partially, the absence of beneficial effects on the part of these compounds in clinical trials carried out to limit organ injury in transplants.
MGraph: graphical models for microarray data analysis
Authors: Wang Junbai , Myklebost Ola , Hovig Eivind
Published: November 2003

Summary: This paper introduces a MATLAB toolbox, MGraph, which applies graphical models as a natural environment to formulate and solve problems in microarray data analysis. MGraph with its graphical interface allows the user to predict genetic regulatory networks by a graphical gaussian model (GGM), and to quantify the effects of different experimental treatment conditions on gene expression profiles by a graphical log-linear model (GLM). The power of graphical models was explored and illustrated through two example applications. First, four MAPK pathways in yeast were meaningfully reconstructed through GGM. Second, GLM was used to quantify the contributions of sex, genotype and age to transcriptional variance in Drosophila melanogaster. This application may provide a valuable aid in the prediction of genetic regulatory networks, as well as in investigations of various experimental conditions that affect global gene expression profiles.

Availability: The MATLAB program MGraph is freely available at http://www.uio.no/~junbaiw/mgraph/mgraph.html for academics.
In silico analysis reveals substantial variability in the gene contents of the gamma proteobacteria LexA-regulon
Authors: Erill Ivan , Escribano Marcos , Campoy Susana , Barbé Jordi
Published: November 2003

Motivation: Motif-prediction algorithm capabilities for the analysis of bacterial regulatory networks and the prediction of new regulatory sites can be greatly enhanced by the use of comparative genomics approaches. In this study, we make use of a consensus-building algorithm and comparative genomics to conduct an in-depth analysis of the LexA-regulon of gamma proteobacteria, and we use the inferred results to study the evolution of this regulatory network and to examine the usefulness of the control sequences and gene contents of regulons in phylogenetic analysis.

Results: We show, for the first time, the substantial heterogeneity that the LexA-regulon of gamma proteobacteria displays in terms of gene content and we analyze possible branching points in its evolution. We also demonstrate the feasibility of using regulon-related information to derive sound phylogenetic inferences.

Availability: Complementary analysis data and both the source code and the Windows-executable files of the consensus-building software are available at http://www.cnm.es/~ivan/RCGScanner/
Parametric alignment of ordered trees
Authors: Wang Lusheng , Zhao Jianyun
Published: November 2003

Motivation: Computing the similarity between two ordered trees has applications in RNA secondary structure comparison, genetics and chemical structure analysis. Alignment of tree is one of the proposed measures. Similar to pair-wise sequence comparison, there is often disagreement about how to weight matches, mismatches, indels and gaps when we compare two trees. For sequence comparison, the parametric sequence alignment tools have been developed. The users are allowed to see explicitly and completely the effect of parameter choices on the optimal sequence alignments. A similar tool for aligning two ordered trees is required in practice.

Results: We develop a parametric tool for aligning two ordered trees that allow users to see the effect of parameter choices on the optimal alignment of trees. Our contributions include: (1) develop a parametric tool for aligning two ordered trees; (2) design an efficient algorithm for aligning two ordered trees with gap penalties that runs in O(n2deg2) time, where n is the number of nodes in the trees and deg is the degree of the trees; and (3) reduce the space of the algorithm from O(n2deg2) to O(n log n · deg2).

Availability: The software is available at http://www.cs.cityu.edu.hk/~lwang/software/ParaTree
A simple and efficient algorithm for gene selection using sparse logistic regression
Authors: Shevade S. K. , Keerthi S. S.
Published: November 2003

Motivation: This paper gives a new and efficient algorithm for the sparse logistic regression problem. The proposed algorithm is based on the Gauss–Seidel method and is asymptotically convergent. It is simple and extremely easy to implement; it neither uses any sophisticated mathematical programming software nor needs any matrix operations. It can be applied to a variety of real-world problems like identifying marker genes and building a classifier in the context of cancer diagnosis using microarray data.

Results: The gene selection method suggested in this paper is demonstrated on two real-world data sets and the results were found to be consistent with the literature.

Availability: The implementation of this algorithm is available at the site http://guppy.mpe.nus.edu.sg/~mpessk/SparseLOGREG.shtml

Supplementary Information: Supplementary material is available at the site http://guppy.mpe.nus.edu.sg/~mpessk/SparseLOGREG.shtml
Early bioinformatics: the birth of a discipline—a personal view
Authors: Ouzounis Christos A. , Valencia Alfonso
Published: November 2003

Motivation: The field of bioinformatics has experienced an explosive growth in the last decade, yet this ‘new’ field has a long history. Some historical perspectives have been previously provided by the founders of this field. Here, we take the opportunity to review the early stages and follow developments of this discipline from a personal perspective.

Results: We review the early days of algorithmic questions and answers in biology, the theoretical foundations of bioinformatics, the development of algorithms and database resources and finally provide a realistic picture of what the field looked like from a resources and finally provide a realistic picture of what the field looked like from a practitioner's viewpoint 10 years ago, with a perspective for future developments.
Normality of oligonucleotide microarray data and implications for parametric statistical analyses
Authors: Giles Peter J. , Kipling David
Published: November 2003

Motivation: Experimental limitations have resulted in the popularity of parametric statistical tests as a method for identifying differentially regulated genes in microarray data sets. However, these tests assume that the data follow a normal distribution. To date, the assumption that replicate expression values for any gene are normally distributed, has not been critically addressed for Affymetrix GeneChip data.

Results: The normality of the expression values calculated using four different commercial and academic software packages was investigated using a data set consisting of the same target RNA applied to 59 human Affymetrix U95A GeneChips using a combination of statistical tests and visualization techniques. For the majority of probe sets obtained from each analysis suite, the expression data showed a good correlation with normality. The exception was a large number of low-expressed genes in the data set produced using Affymetrix Microarray Suite 5.0, which showed a striking non-normal distribution. In summary, our data provide strong support for the application of parametric tests to GeneChip data sets without the need for data transformation.
PreP: gene expression data pre-processing
Authors: García de la Nava Jorge , van Hijum Sacha , Trelles Oswaldo
Published: November 2003

Summary: PreP is a versatile, powerful, standalone application that aims at pre-processing gene expression data.

Availability: Documentation and executable file for MS-Windows are available at http://chirimoyo.ac.uma.es/bitlab/services/index.htm
NCL: a C++ class library for interpreting data files in NEXUS format
Authors: Lewis Paul O.
Published: November 2003

Summary: The NEXUS Class Library (NCL) is a collection of C++ classes designed to simplify interpreting data files written in the NEXUS format used by many computer programs for phylogenetic analyses. The NEXUS format allows different programs to share the same data files, even though none of the programs can interpret all of the data stored therein. Because users are not required to reformat the data file for each program, use of the NEXUS format prevents cut-and-paste errors as well as the proliferation of copies of the original data file. The purpose of making the NCL available is to encourage the use of the NEXUS format by making it relatively easy for programmers to add the ability to interpret NEXUS files in newly developed software.

Availability: The NCL is freely available under the GNU General Public License from http://hydrodictyon.eeb.uconn.edu/ncl/

Supplementary information: Documentation for the NCL (general information and source code documentation) is available in HTML format at http://hydrodictyon.eeb.uconn.edu/ncl/
MetaGeneAlyse: analysis of integrated transcriptional and metabolite data
Authors: Daub Carsten O. , Kloska Sebastian , Selbig Joachim
Published: November 2003

Summary: New techniques in sample preparation allow high throughput analysis of samples on the transcriptional as well as on the metabolic level. We present a service accessible via the web that allows the analysis of integrated data sets that combine gene-expression data and metabolic data. After uploading, data sets can be normalized, clustered by various methods and results can be graphically visualized. All calculations are carried out on a server, so even time- and memory-consuming analyses can be done independently of the performance of the client.

Availability: The service is accessible via web-interface at http://metagenealyse.mpimp-golm.mpg.de/
Missing-value estimation using linear and non-linear regression with Bayesian gene selection
Authors: Zhou Xiaobo , Wang Xiaodong , Dougherty Edward R.
Published: November 2003

Motivation: Data from microarray experiments are usually in the form of large matrices of expression levels of genes under different experimental conditions. Owing to various reasons, there are frequently missing values. Estimating these missing values is important because they affect downstream analysis, such as clustering, classification and network design. Several methods of missing-value estimation are in use. The problem has two parts: (1) selection of genes for estimation and (2) design of an estimation rule.

Results: We propose Bayesian variable selection to obtain genes to be used for estimation, and employ both linear and nonlinear regression for the estimation rule itself. Fast implementation issues for these methods are discussed, including the use of QR decomposition for parameter estimation. The proposed methods are tested on data sets arising from hereditary breast cancer and small round blue-cell tumors. The results compare very favorably with currently used methods based on the normalized root-mean-square error.

Availability: The appendix is available from http://gspsnap.tamu.edu/gspweb/zxb/missing_zxb/ (user: gspweb; passwd: gsplab).
Disease-associated variants in PYPAF1 and NOD2 result in similar alterations of conserved sequence
Authors: Albrecht Mario , Lengauer Thomas , Schreiber Stefan
Published: November 2003

Sequence variations in the gene products PYPAF1/CIAS1 and NOD2/CARD15 have been associated with several autoinflammatory diseases that, although clinically different, share a similar inflammatory pathophysiology. A multiple sequence alignment of homologous proteins demonstrates that some of the missense variants are located in highly conserved regions of the NTPase domain and possibly impair NTP-hydrolysis. Intriguingly, one of the variations, which is found identically in PYPAF1 and NOD2, is located at the same alignment position. Our findings suggest that evolutionary gene duplication can give rise to disease families because variants affect conserved sequence in a similar fashion.
An exploratory study of women in micro enterprises: gender‐related differences
Authors: Sandberg Karl W.
Published: November 2003

This article assesses gender‐related differences in rural enterprises and examines implications for development of economic policy and services in a rural district of Sweden. The article focuses on female owned micro enterprises. A quantitative and qualitative survey of 32 micro enterprise owners was carried out. Focus was on owner attitudes toward local governmental policies and programmes. There were not strong differences between genders for items using multiple‐choice responses. Where qualitative, written responses were solicited there were some differences in perceptions and attitudes. The female respondents tended to write more and respond in ways that suggest that they tend to reflect more upon the future and new possibilites. Differences in style of operation were evident; others have reported this. Written responses from female participants described in greater detail and more clearly the ongoing need for governmental support of networking activities and other programmes that promote cooperation and resource pooling (regardless of gender).
Total Syntheses of (±)-Phycocyanobilin and Its Derivatives Bearing a Photoreactive Group at D-ring
Authors: Kakiuchi Takashi , Kato Hirohide , Jayasundera Krishanthi Padmarani , Higashi Taijiro , Watabe Kazuhiko , Sawamoto Daisuke , Kinoshita Hideki , Inomata Katsuhiko
Published: November 2003

(±)-Phycocyanobilin and its derivatives bearing a photoreactive group at D-ring were first synthesized by the development of a new and convenient method for the preparation of A-ring, transesterification for propanoic acid side-chains of the pyrrole derivative common to B- and C-rings, and deprotection of allyl ester side-chains with a palladium catalyst to avoid migration of exocyclic olefin of A-ring.
Reaction of Trivalent Phosphorus Compounds with an Fe(III) Complex in the Presence of Alcohol. Single Electron Transfer Accompanied by a P-O Bond Formation
Authors: Yasui Shinro , Itoh Kenji , Tsujimoto Munekazu , Ohno Atsuyoshi
Published: November 2003

Reactions of various types of trivalent phosphorus compounds with iron(III) complex in the presence of ethanol have been examined kinetically, showing that the single electron transfer from the former compounds to the latter is followed by rapid reaction of the resulting trivalent phosphorus radical cations with ethanol.
Acceleration Effects of Phosphine Ligands in the Nickel Catalyzed Methylation of Aldehydes Using Trimethylaluminum
Authors: Ichiyanagi Tsuyoshi , Kuniyama Satoru , Shimizu Makoto , Fujisawa Tamotsu
Published: November 2003

A nickel catalyzed methylation of aldehydes was conducted successfully using trimethylaluminum as an alkylation reagent. In the presence of a phosphine or phosphite ligand, the reaction was considerably accelerated to give the methylation product in good yields.
Chirality-dependent Gel Formation from Sugars and Boronic-acid-appended Chiral Amphiphiles
Authors: Kimura Taro , Shinkai Seiji
Published: November 2003

Aqueous solutions containing a boronic-acid-appended amphiphile with a L-glutamate segment were gelatinized in the presence of certain saccharides. Examination of the gelation temperature, DSC, and the absorption spectra of a cyanine dye revealed that this is a novel system having two phase-transitions, viz., the sol-gel phase transition and the gel-liquid crystal phase transition.
An Unusual Isotactic Coordination Polymer Chain Assembled by Mn(II) and O-phthalate: [Mn(μ-phth)(phen)(H2O)2]·H2O (phth = o-phthalato; phen = 1,10-phenanthroline)
Authors: Zhang Yugen , Jianmin Li , Min Zhu , Wang Quanming , Wu Xintao
Published: November 2003

The complex [Mn(μ-phth)(phen)(H2O)2]·H2O (phth = o-phthalato; phen = 1,10-phenanthroline), in which an unusual isotactic coordination polymer chain is assembled by Mn(II) and o-phthalate dianion, an amphiphilic channel which has hydrophilic inside and hydrophobic outside is formed via hydrogen bonds, has been isolated and structurally characterized.
Synthesis of Fluorenebisphenoxy Derivatives by Acid-sulfur Compound Catalyzed Condensation Reaction
Authors: Yamada Mitsuaki , Sun Jun , Suda Yasuhiro , Nakaya Tadao
Published: November 2003

An efficient method for the synthesis of fluorenebisphenoxy derivatives from fluorenone and phenoxy compounds is successfully performed by the combined use of concentrated sulfuric acid as catalyst and 3-mercaptopropionic acid as co-catalyst. Several fluorenebisphenoxy derivatives are obtained in good yields by this one-step reaction.
Structural Diversity of Copper Complexes with 2,2′-Dipyridyldisulfide. From Dimer to Infinite Sheet Structure Both in Solid State and in Solution
Authors: Kubo Sachiko , Nishioka Takanori , Ishikawa Keiichirou , Kinoshita Isamu , Isobe Kiyoshi
Published: November 2003

Reaction of 2,2′-dipyridyldisulfide (dpds) with CuBr2 in methanol provide a extended sheet or a discrete dimer structure. The discrete dimer [CuBr(dpds)]2 change to the sheet structure of [CuBr(dpds)]n by heat in the solid state or prolonged standing in reaction system.
Stereospecific Epoxidation of 2-Hexene with Molecular Oxygen on Photoirradiated Titanium Dioxide Powder
Authors: Ohno Teruhisa , Kigoshi Takayo , Nakabeya Keizo , Matsumura Michio
Published: November 2003

Photocatalytic oxidation of 2-hexene on TiO2 powder was investigated under a stream of oxygen gas. The main product was 2,3-epoxyhexane with the chemical yield ranging from 65% to 83% depending on the TiO2 powders. When trans-2-hexene was used as the starting material, the epoxide was also trans. On the other hand, cis epoxide was the chief product from cis-2-hexene. From mixed 2-hexene (trans/cis = 1.7), larger amounts of trans epoxide were obtained than cis-epoxide in the initial period of the reaction, indicating that trans-2-hexene is more reactive than the cis isomer on the photocatalyst.
High Nuclearity in a Zinc(II) Complex with 1,3-Bis(salicylamino)-2-propanol
Authors: Mikuriya Masahiro , Tsuru Noriyo , Ikemi Shinichiro , Ikenoue Shuichi
Published: November 2003

A zinc(II) complex with 1,3-bis(saliclylamino)-2-propanol (H3La), [Zn8La4(OH)2](ClO4)2·8CH3OH, has been isolated and characterized by X-ray crystallography, which reveals a unique cage structure composed of eight zinc atoms and four alkoxo-oxygen and eight phenoxo-oxygen bridges of La3−.
Selective Fluorescence Signalling of Saccharides in Their Furanose Form
Authors: Cooper Christopher R , James Tony D
Published: November 2003

A boronic acid binding site and biphenyl fluorophore has been used to create a fluorescent PET (photoinduced electron transfer) sensor for saccharides in aqueous solution at pH 7.77. Formation of five or six membered cyclic boronate esters can be “read out” by the relative fluorescence intensity.
Molecular Weight Effect on Secondary Structural Formation for Uniform Polypeptides with a Repeating Sequence of Glycine-Rich Sequence of Spider Dragline Silk
Authors: Fukushima Yasumasa
Published: November 2003

Polypeptides with a repeating sequence of glycine-rich sequence of spider dragline silk formed a β-sheet structure which exists in the crystalline region. The β-sheet content increased with increasing the molecular weight of the polypeptides. The formation of the β-sheet structure could be caused by the intramolecular as well as intermolecular conventional hydrogen bondings.
Electrochemical STM Observation of Well-ordered Adsorbate on Cu(111) Electrode Surfaces in an Alkaline Electrolyte
Authors: Matsuoka Osamu , Yamamoto Sadaaki , Sugiyama Shoko , Miyazoye Satoru , Nozoye Hisakazu
Published: November 2003

Electrochemical scanning tunneling microscopy revealed two kinds of periodical structure of bright spot on Cu(111) electrode surfaces in NaOH aqueous solutions. These structures show the arrangement of the CuOH surface species formed by the reduction of subsurface oxygens.
Improved Ionic Conductivity of PEO/Sulfonamide Lithium Salt Hybrid by the Addition of LiTFSI
Authors: Tominaga Yoichi , Ohno Hiroyuki
Published: November 2003

Poly(ethylene oxide) (PEO) with the average molecular weight of 500, 1000, or 1900 having methane sulfonamide lithium salt in both chain ends was used as matrix to solubilize lithium bis-(trifluoromethane sulfonyl) imide (LiTFSI). Ionic conductivity of the above-mentioned PEO/salt hybrid was improved by the addition of LiTFSI. These mixtures were amorphous and lost the melting point of PEO part. The ionic conductivity was from 4 to 30 times higher than that of hybrid without LiTFSI since the number of carrier ions increased without remarkable elevating the glass transition temperature.
Modulation of the Oscillation Period for an Electrochemical Oscillation in an “H2O2-Acid-Pt Electrode” System by Deposition of a Small Amount of Metal Atoms
Authors: Nakanishi Shuji , Hommura Hayato , Mukouyama Yoshiharu , Matsuda Toshihiko , Nakato Yoshihiro
Published: November 2003

The oscillation period of a current oscillation in reduction reaction of H2O2 on a Pt electrode in an acidic solution becomes shorter with time by addition of a small amount of Cu2+, AuCl4− or Ru3+ ions to the solution, whereas the period becomes longer by addition of Ag+ ions. The difference is explained by assuming deposition of dispersed metal atoms during the oscillation together with a difference in the H2O2-reduction mechanism among the metals.
Synthesis and Magnetic Properties of Binuclear Iron(III) Complexes Containing Photoisomerization Ligand
Authors: Hayami Shinya , Inoue Katsuya , Osaki Susumu , Maeda Yonezo
Published: November 2003

Binuclear iron(III) spin-crossover complex [Fe2(salten)2(az)](BPh4)2 (az = azobis(4-pyridine)) was synthesized and characterized by X-ray single-crystal diffraction, Mössbauer spectra, magnetic susceptibilities and electronic spectra. This complex contains the ligand which is able to photoisomerize as a bridging ligand. The complex exhibited the spin-crossover behavior depending on temperature in solution and solid state. Mössbauer measurements indicated that the complex exhibited rapid spin-equilibrium behavior at room temperature.
Neural Basis of Vision
Authors: Bullier Jean
Published: November 2003

The neural basis of vision is examined from the point of view of the anatomical organization of the primate visual system and the responses of single neurons. The recent developments of imaging studies in humans are also examined. The chapter opens with a section on the receptive field of visual neurons, from the historical definition to modern concepts. The following section is devoted to the various representations of receptive fields parameters: retinotopic and nonretinotopic maps in various structures of the visual system. The third section is a description of the anatomical and functional organization of the primate visual system, with a special emphasis on the different cortical areas, their roles, and their interactions. The fourth section is devoted to the analysis of the relationship between visual perception and the responses of single units in nonhuman primates. The last section addresses a number of unanswered or rarely addressed issues in animal studies, such as the neural basis of consciousness and mental representations, the importance of visual exploration of the environment, the neural basis of 3D vision, and the role of feedback connections.
Speech Perception
Authors: Jusczyk Peter W. , Luce Paul A.
Published: November 2003

The scientific study of the perception of spoken language has been a productive area of research for over fifty years. During this period, we have learned much about infants' and adults' remarkable capacities for perceiving and understanding the sounds of their language. We present a selective review of the past half century of research on speech perception, focusing on three principle topics: early work on the discrimination and categorization of speech sounds, more recent efforts to understand the processes and representations responsible for spoken word recognition, and research on how infants acquire the capacity to perceive their native language. Our intent is to provide the reader with a sense of the progress our field has made over the last half century in understanding the human's extraordinary capacity for the perception of spoken language.
Touch and Haptics
Authors: Hollins Mark
Published: November 2003

This chapter describes the psychophysics of touch—how tactile abilities and perceptions are measured, and what those measurements reveal about the somatosensory system. The ability to discern spatial aspects of tactile stimuli, such as how many are present and where they are on the skin, has been extensively studied: A key finding in this area is that resolution acuity predicts performance on a range of other tasks. Researchers have also examined temporal aspects of touch, especially through the use of vibration. Studies using masking and other paradigms have revealed the existence of vibrotactilechannelsassociated with mechanoreceptor classes. Signals in these channels encode the intensity and frequency of vibratory stimuli, and contribute to the perception of textured surfaces. Many tactile stimuli involve temporal changes in spatial aspects of stimulation; an understanding of how these are perceived requires that a variety of spatio‐temporal distortions be taken into account. The chapter ends with a discussion ofhaptics(active touch) by which an attentive observer explores an object to discover its properties and identity. Kinesthetic as well as cutaneous signals play a role in this search for information, but how they are combined is a process that is only beginning to be understood.
Olfaction
Authors: Dalton Pamela
Published: November 2003

Within the past decade, substantial advances in our knowledge of the transduction, coding, and information‐processing of olfactory signals has occurred. These advances have been accompanied by significant developments from psychophysical and behavioral studies of olfactory processing that illustrate the importance of a multilevel approach for studying the olfactory system.

This chapter focuses primarily on studies of human olfaction, beginning with a description of the anatomical basis for olfaction, followed by an examination of the fundamentals of sensory processing, descriptions of standard methods for studying olfaction, and an overview of basic results from psychophysical analyses of individuals with normal and impaired olfactory ability. Although the adoption of more sophisticated and reliable methods for studying olfaction appears to have reduced the extreme variability in sensitivity and response that has been historically observed, factors that contribute to individual variation in olfactory performance, such as gender, age, and exposure are also described. Finally, the role of olfaction in memory, affective processes, and higher‐level cognition is reviewed.
Cognitive Neuroscience
Authors: Humphreys Glyn W.
Published: November 2003

In this chapter attempts are reviewed that have been made to built the bridge between functional models of human cognition and neural models of brain activity. Drawing on examples of object recognition and visual attention, I provide a historical overview of the initial attempts to build this bridge, using data from neuropsychology. I subsequently review more recent approaches using functional brain imaging (PET and fMRI), single cell recording, EEG, RP, MEG and, latterly, TMS, to measure brain operation. I discuss the problems in making links between brain and cognition, and some of the contributions that neural‐level theories can make to theories pitched at a functional level.
Psycholinguistics
Authors: Clark Herbert H. , Wege Mija M. Van Der
Published: November 2003

Psycholinguistics in the study of how people process language. People use spoken language to coordinate such joint activities as business transactions, story telling, and planning. In doing so, they work turn by turn, relying on adjacency pairs, such as question plus answer, or assertion plus acknowledgment, and they ground what is said as they proceed. Speaking itself is a process with overlapping stages. For each utterance, speakers decide on a message, select the concepts and syntactic frame required for that message, assemble these in an appropriate order, formulate a phonological code, and then articulate the right sounds. Listeners, for their part, take in these sounds segment by segment. They narrow down on words and phrases instantly as these become specified uniquely in the context. Listeners rely on pragmatic information not only in this process, but also in filling conceptual gaps in their understanding with bridging and elaborative inferences. The words people use are stored in a mental lexicon as entries with conventional meanings. But in talking face‐to‐face, people also use gestures—such as emblems, iconic gestures, and pointing—which they coordinate with their words. People also create broader models of the situations being spoken about. These models represent such things as visual and spatial features of the situations, cultural schemas, and mental simulations of imagined scenes and events.
Concepts and Categorization
Authors: Wisniewski Edward J.
Published: November 2003

Traditionally, concepts have been viewed as mental representations that enable people to categorize or pick out a group of nonidentical but equivalent things (e.g., a concept of dog allows one to categorize many entities as “dogs” even though they are not identical). This chapter provides a broad overview of the fields of concepts and categorization, describing early research but giving special attention to work published in the last 15 years. It describes different views of the structure of human concepts (i.e., what they consist of), as well as formal mathematical models of categorization and category learning. These models assume that categorization is based on how similar an entity is to other members of the empirical category. This chapter describes research addressing the sufficiency of this approach, which suggests that similarity is a dynamic process involving the comparison of complex mental representations, and that category learning involves the integration of empirical learning with background knowledge. The chapter also examines research describing the taxonomic and thematic organization of concepts in memory. Finally, the chapter addresses the functions that concepts serve beyond their traditional role in classification.
Culture and Cognition
Authors: E. Nisbett Richard , Norenzayan Ara
Published: November 2003

We review evidence for the mutual interdependence of cultural and cognitive processes. Some cognitive content, assumed by many psychologists to be infinitely variable, appears to be universal, including theories of mechanics, biology, and mind. These domain‐specific theories constrain the diversity of human thought and the range of cultures possible. On the other hand, many cognitive processes assumed to be universal are highly susceptible to cultural variation. We consider recent developments regarding cultural variation in mathematical and folkbiological reasoning, deductive reasoning in traditional societies, as well as the linguistic relativity hypothesis, field dependence, and situated cognition. We then examine recent research on marked cultural differences in holistic vs. analytic modes of reasoning primarily between East Asian and Western cultures.
Associative Structures in Pavlovian and Instrumental Conditioning
Authors: Hall Geoffrey
Published: November 2003

The associative analysis of conditioning assumes aconceptual nervous systemconsisting of a set of units (nodes). Some nodes are are activated by specific external stimuli; others, when activated, result in the emission of particular patterns of behavior (responses). The behavioral changes produced by conditioning procedures are explained in terms of the formation of links between nodes that allow activity in one to excite activity in another. The aim of this chapter is to specify what nodes are involved in a given conditioning procedure and the pattern of interconnections that forms among them. Three procedures are considered: Excitatory conditioning, in which a Pavlovian conditioned stimulus reliably precedes the occurrence of an unconditioned stimulus or, for the instrumental case, in which a given response reliably produces a given outcome; inhibitory conditioning, in which the association between the relevant events is discontinued (the conditioned stimulus or the response occurs without consequence); and complex conditioning, in which the consequence of the conditioned stimulus or of the response varies according to which other events are presented. It is demonstrated that the standard assumptions of associative theory can explain the results of the first of these procedures; that the second requires the further assumption that links can inhibit the tendency of nodes to be activated; and that the last requires further new assumptions (that nodes can encode the configural properties of stimuli, or that links can operate on other links as well as on nodes, or both).
Learning
Authors: Miller Ralph , Escobar Martha
Published: November 2003

This chapter reviews current knowledge concerning basic cognition in simple situations, focusing on how stimulus‐specific experience modifies behavior. First, we discuss in an atheoretical manner the empirical laws of conditioning and learning, which describe changes in stimulus control of behavior as a function of specific experiential variables across different species, tasks, and motivational factors. Specifically, we describe (a) factors that influence acquisition of behavioral control (e.g., stimulus salience, predispositions, stimulus similarity, continguity, contingency); (b) stimulus mediation of acquired behavior (e.g., second‐order conditioning, sensory preconditioning, conditioned inhibition), stimulus competition and interference (between cues and between outcomes trained together and apart), facilitation, and summation; and (c) instrumental contingencies and motivation. The second part of the chapter provides an overview of psychological models of acquired behavior, with an emphasis on differentiating acquisition‐focused and performance‐focused models. We first outline the units of analysis that are used by psychological models of conditioning and learning, and then review how each family of models accounts for the empirical laws described in the first part of the chapter. We conclude with a critical assessment of learning theories and outline some of the potential contributions that stem from the study of the empirical and theoretical principles of learning.
Learning Instincts
Authors: Gould James L.
Published: November 2003

During the modern development of the study of behavior, Behaviorists maintained that all behavior was learned, and instinct was a myth. Ethologists considered instinct the main factor in behavior, with learning serving as a kind of adjunct; they believed that lab studies were irrelevant to the behavior of animals in nature. In retrospect, both groups were right up to a point: Most of the main phenomena studied by Behaviorists turn out to be at work in a wide range of “real” animals, while even humans depend on an enormous array of innate programming to survive. The synthetic view outlined here sees most learning as based on general processes, but customized through the operation of natural selection in context‐ and species‐specific ways to solve particular problems.
Thirst and Water‐Salt Appetite
Authors: Rowland Neil E.
Published: November 2003

In this chapter, the current theoretical concepts and known physiological mechanisms for mammalian fluid homeostasis are reviewed. Fluid loss from the intracellular fluid compartment is sensed by osmoreceptors, which are located peripherally in structures such as the liver as well as in the brain, and underlie osmotic or intracellular thirst and water intake. Fluid loss from the extracellular fluid compartment is sensed by pressure‐sensitive cardiopulmonary receptors, and underlies hypovolemic or extracellular thirst and water intake. The peptide hormone, angiotensin II, released during hypovolemia may contribute to extracellular thirst. Both types of dehydration produce vasopressin secretion; its primary role is to minimize further fluid loss from the kidney and it does not seem to contribute to thirst. Brain structures of the forebrain lamina terminalis are critically involved in transduction and integration of this neurosensory and hormonal information to engage drinking behavior, for example naturally‐occurring thirst such as after deprivation or during meals. Aspects of thirst during ontogeny and aging, as well as genetic and individual differences in thirst are discussed briefly. Extracellular dehydration involves loss of sodium as well as water, and so both preference and appetite for sodium, and the roles of the hormones aldosterone and angiotensin II are reviewed. Several problem areas in which our knowledge is less complete are also identified.
Social Behavior
Authors: Crawford L. Elizabeth , Luka Barbara , Cacioppo John T.
Published: November 2003

To understand the interplay between individuals and social context, social psychology must span levels of analysis. At the social level, social psychology examines how the behavior and attitudes of individuals are influenced by social factors. At the cognitive level, it addresses how the individual interprets, evaluates, and ascribes meaning to the social world. At the biological level, social psychology examines individuals as biological entities whose physiology influences, and is influenced by, social life. This chapter addresses issues at each of these levels, providing an overview of central topics in experimental social psychology such as motivation, emotion, attitudes, social influence, the self, social cognition, and social neuroscience. We conclude that because human behavior is multiply determined, the study of the individual may be incomplete without considering the independent, interactive, and reciprocal effects of biological, cognitive, and social factors.