bluuebunny/crossref_metadata_2025 huggingface dataset:
Foundations of multi‐dimensional metric scaling in Cayley‐Klein geometries
Authors: Drösler Jan
Published: August 2011

Two‐dimensional metric scaling is based on the relations of incidence and orthogonality and on the motion of reflection in a straight line. Together with a set of optional postulates concerning different types of orthogonality these primitives are sufficient for operationalizing the Cayley‐Klein geometries for use in the psychological laboratory. They include the three Riemannian geometries (elliptic, Euclidean and hyperbolic) as special cases. The representation refers to a vector space over an unspecified field. The advantage of this lies in the identifiability of the geometry present, before technical axioms have been invoked in order to secure a field of real numbers.

The approach appears to be commendable because it yields new solutions to classical problems from monocular and binocular space perception as well as from colour vision. Extensions to derived measurement outside of psychophysics and to three and more dimensions of multidimensional scaling are reported.
Variations of the triangular method and the relationship of its unidimensional probabilistic models to three‐alternative forced‐choice signal detection theory models
Authors: Frijters J. E. R.
Published: August 2011

The experimental procedure involved in the application of the statistical triangle test and some of the limitations of this method are briefly discussed. Two types of unidimensional distance models, the triangle constant method and the normal Thurstone‐Ura model, are briefly reviewed and the logistic Thurstone‐Ura model is developed. The two versions of the Thurstone‐Ura model are shown to be remarkably different from the corresponding versions of the three‐alternative forced‐choice signal detection theory model.

Some theoretical and experimental differences between the triangular constant method model, the Thurstone‐Ura model and the 3‐AFC SDT model are discussed. Finally, by analysis of experimental data, it is shown that the theoretical distinction between the Thurstone‐Ura model and the 3‐AFC SDT model is useful because it appeared the key for the resolution of the ‘paradox of discriminatory non‐discriminators' (Gridgeman, 1970).
Models and estimation procedures for the calibration of examiners
Authors: Paul Sudhir Ranjan
Published: August 2011

In large public examinations (e.g. GCE ‘O’ Levels) careful attention is given, by construction of marking schemes and by other means, to the problem of ensuring that the examiners mark on a common scale, but doubt remains as to how far this is achieved. An additive model and a linear relationship model are proposed to describe the examiners' behaviour in marking scripts, and estimators of the parameters of the models are given. The models are compared by applying them to real examination data. The conclusion is drawn that there is very little to choose from between the two models and that the additive model representation seems adequate.
Item sampling, guessing and decision‐making in achievement testing
Authors: van den Brink Wulfert P. , Koele Pieter
Published: August 2011

An item‐sampling model that takes the effect of guessing into account was used to calculate the number of items and the cutting score a test should have to make a decision of mastery or non‐mastery with prescribed precision. The results show that the required number of items is markedly larger than suggested by similar approaches not using the number of alternatives of the items as a parameter. It is concluded that multiple choice tests of usual length are highly fallible decision aids.
Measurement theory and examinations
Authors: French Simon
Published: August 2011

It is standard practice in examinations to sum a candidate's marks over individual papers and award a final grade according to the overall total. This paper questions the adequacy of such an approach and, drawing on results from the theory of measurement, tentatively suggests an alternative.
Shades of all‐or‐none learning: A stimulus sampling model
Authors: Nicolson Roderick I.
Published: August 2011

A model of paired‐associate learning is produced, based on stimulus sampling theory. The model provides an excellent fit for data from both a two‐alternative and a three‐alternative experiment, and resolves several problems that beset Markov models of the process.
Appropriateness measurement with polychotomous item response models and standardized indices
Authors: Drasgow Fritz , Levine Michael V. , Williams Esther A.
Published: August 2011

The test scores of some examinees on a multiple choice test may not provide satisfactory measures of their abilities. The goal of appropriateness measurement is to identify such individuals. Earlier theoretical and experimental work considered examinees answering all, or almost all, test items. This article reports research that extends appropriateness measurement methods to examinees with moderately high non‐response rates. These methods treat non‐response as if it were a deliberate option choice and then attempt to measure the ‘appropriateness’ of the pattern of option choices. Earlier studies used only the dichotomous pattern of ‘right’ and ‘not right’ answers. A general polychotomous model is introduced along with a technique called ‘standardization’ designed to reduce the observed confounding between measured appropriateness and ability. A standardized appropriateness index based on a polychotomous model yielded higher rates of detection of simulated spuriously low examinees than the analogous index based on a dichotomous model. However, the converse was true for simulated spuriously high examinees. Standardization was found to reduce greatly the interaction between ability and measured appropriateness.
Estimating the effects of various clustering schemes on recall order
Authors: Robertson Chris , Ellis Hadyn D.
Published: August 2011

A model is postulated for the recall of items in free recall experiments which allows the effects of different clustering schemes on recall order to be estimated. It is also possible to investigate the interaction between two clustering schemes. Details of fitting the model and estimating the relevant parameters are presented. The use of the model is illustrated by reference to an experiment involving the recall of names of famous personalities presented in photographic form. The results of fitting the model to the data suggest that while recall order is influenced primarily by the occupational categories of the personalities (film stars, pop stars, sports personalities, etc.), the facial similarities among the personalities are also important.
Backward, forward and stepwise automated subset selection algorithms: Frequency of obtaining authentic and noise variables
Authors: Derksen Shelley , Keselman H. J.
Published: August 2011

The use of automated subset search algorithms is reviewed and issues concerning model selection and selection criteria are discussed. In addition, a Monte Carlo study is reported which presents data regarding the frequency with which authentic and noise variables are selected by automated subset algorithms. In particular, the effects of the correlation between predictor variables, the number of candidate predictor variables, the size of the sample, and the level of significance for entry and deletion of variables were studied for three automated subset algorithms: BACKWARD ELIMINATION, FORWARD SELECTION, and STEPWISE. Results indicated that: (1) the degree of correlation between the predictor variables affected the frequency with which authentic predictor variables found their way into the final model; (2) the number of candidate predictor variables affected the number of noise variables that gained entry to the model; (3) the size of the sample was of little practical importance in determining the number of authentic variables contained in the final model; and (4) the population multiple coefficient of determination could be faithfully estimated by adopting a statistic that is adjusted by the total number of candidate predictor variables rather than the number of variables in the final model.
Effects on response time of factors selectively influencing processes in acyclic task network with OR gates
Authors: Schweickert Richard , Wang Zhongqi
Published: August 2011

The mental processes involved in performing some tasks can be represented as directed arcs in an acyclic network. A path directed from the head of one arc to the tail of another indicates that the process represented by the first arc must be executed prior to the process represented by the second arc. If there is no directed path from one arc to another, the corresponding processes can be executed concurrently. Information about the arrangement of processes in an acyclic network can be found from the effects on response times of factors selectively influencing the processes. The methodology was developed earlier for critical path networks, in which a process begins execution when all its immediate predecessors have finished. This paper considers shortest path networks, in which a process begins execution as soon as any immediate predecessor is finished. Results analogous to those for critical path networks are reported. New results are presented enabling investigators to distinguish sequential and concurrent processes in both critical path and shortest path networks. This information is sufficient to construct an acyclic network representing the processes. Further, by examining the effects of selectively influencing processes, one can determine whether a task network is a critical path network or a shortest path network.
Qualitative generalizations from quantitative analyses
Authors: MaCdonald Ranald R.
Published: August 2011

This paper considers the circumstances under which qualitative generalizations from statistical tests are possible. When observations from different conditions are assumed to be identically distributed except for a location parameter, then any difference that is established between the conditions will be entirely due to location. Furthermore, the direction of these differences will be independent of the statistic used, the scale of measurement or the shape of the distributions. This implies that significant differences between conditions generalize to latent variables (variables which are monotonie transformations of observed variables). Obtaining a significant difference between two conditions establishes the direction of that difference and obtaining significance in a test of differences between more than two conditions establishes a nonparametric correlation between the observed and population means. To make equivalent generalizations from main effects in factorial analyses of variance it must be assumed that the observations are random with respect to the other factors in the design. Correlation and regression analyses generalize to latent variables where all the variables are monotonically related. However, this implies that there is only one ordinally distinct latent variable. Where non‐monotonic relationships are possible and one distribution is treated as fixed, significant correlation and regression analyses do not generalize to latent variables. It is argued that while linear modelling may be an appropriate method of making quantitative predictions from a set of random variables, tests of differences are more interpretable than correlations where the aim is to study theoretically interesting latent variables.
Handling ordinal variables in three‐way analysis of quantification matrices for variables of mixed measurement levels
Authors: Kiers Henk A. L.
Published: August 2011

For the analysis of variables of mixed measurement levels a class of methods can be used that is based on three‐way analysis of quantification matrices for nominal or quantitative variables. This class of methods incorporates some well‐known techniques but also offers a series of interesting new alternatives for the analysis of nominal or quantitative variables. Ordinal variables have received hardly any attention in this class of methods, and are usually treated as if they are quantitative variables. In the present paper this gap is filled by constructing quantification matrices for ordinal variables via optimal scaling of the ordinal variables, thus yielding optimal quantification matrices for these variables. Algorithms for this optimal scaling procedure are developed, and the optimal scaling procedures are compared to optimal scaling of ordinal variables in the context of principal components analysis and multidimensional scaling.
Scaling and combining examination marks
Authors: Biggins J. D. , Yue K. K.
Published: August 2011

Biggins, Loynes & Walker (1986) considered the problem of scaling and combining examination marks from several papers to obtain transformed marks and an overall measure of each candidate's performance in the examination. Their approach is to obtain the transformations and the overall marks by the minimization of a suitably chosen loss function subject to a single constraint. In the main, following Broyden (1983), they consider the case where the allowed transformation is multiplication by a constant (which varies from paper to paper). This paper discusses the same problem but with a richer class of possible transformations, the main example being regression splines with end‐point restrictions. These end‐point restrictions will mean that the curve can be forced to preserve the mark range, by passing through (0, 0) and (100,100), for example. If grades rather than marks are returned the problem becomes the well‐studied one of scaling categorical attributes. Our formulation applies in this case also, allowing us to connect the proposals with existing scaling literature. The general issue of how to incorporate the expectation that transformation curves should not be too far from the 45° line is also addressed, with the device of using fictitious candidates, introduced by Biggins et al. (1986), being extended to this context.
In defence of ‘none of the above’
Authors: García‐Pŕrezt Miguel A.
Published: August 2011

Based on a review of empirical research on the subject, items with the last option reading ‘none of the above’ (NOTA items) have been claimed to be of no advantage over conventional items (Haladyna & Downing, 1989a, b). This paper comments briefly on the weakness of the evidence on which this conclusion is based, and points out some facts that might have contaminated prior empirical research on the advisability of NOTA items, thus possibly invalidating the above conclusion. A theoretical study comparing both item types is also presented in this paper. Finite state theory is used to derive multinomial models for either type of item. These models are then used to obtain maximum likelihood point and interval estimates of the examinees' abilities. Analysis of these estimates shows that NOTA items yield narrower confidence intervals than their conventional counterparts. Thus, they should be preferred over conventional items when accuracy in ability estimation is a goal.
Computing confidence intervals for the slope of the biweight midregression and Winsorized regression lines
Authors: Wilcox Rand R.
Published: August 2011

Robust and resistant regression has taken on new importance in recent years with the realization that psychometric measures often have heavy‐tailed distributions with extreme outliers. While many resistant regression methods are available, little is known about how a researcher might compute a confidence interval for the corresponding parameters. The primary goal in this paper is finding a method of computing reasonably accurate confidence intervals for the slope of two resistant regression methods: the biweight midregression and Winsorized regression. Several ‘obvious’ bootstrap methods for computing confidence intervals were found to be highly unsatisfactory. A relatively unobvious method was found to perform reasonably well when using biweight midregression, and fairly well for the other regression method except for one extreme situation described in the paper. In terms of power, no situation was found where ordinary least squares is to be preferred over Winsorized regression, while Winsorized regression can have a substantial advantage over ordinary least squares. There are situations where the biweight midregression has substantially more power than ordinary least squares, but when the predictor has a highly skewed distribution, there are situations where the reverse is true. The relative merits of the two resistant regression methods are discussed.
Modelling recall ‐ Clustering and order effects
Authors: Robertson Chris
Published: August 2011

A model of recall order discussed by Robertson (1990) is extended to investigate the simultaneous effects of clustering and presentation order effects in single trial free recall. Further extensions are presented to model recall order within multi‐trial free recall. Two examples are presented to illustrate the types of effects which can be included.
Detecting patterns of bivariate mean vectors using model‐selection criteria
Authors: Huang Chuen‐Chuen Joyce , Dayton C. Mitchell
Published: August 2011

Three model‐selection criteria, (1) AIC (Akaike, 1973), (2) SIC (Schwarz, 1978), and (3) CAIC (Bozdogan, 1987), were evaluated for detecting patterns of differences among mean vectors with bivariate data. This simulation study involved three and five group cases with equal‐sized samples of 10, 20 and 50. Ten different distributions, including situations with extreme skewness and kurtosis, were generated to assess the robustness of the criteria with respect to non‐normality. Both homogeneous and heterogeneous covariances cases were examined. The three model‐selection criteria were compared in terms of correct decision rates based on 500 replications for each condition studied. Results indicate that all three criteria are relatively robust with respect to non‐normality. SIC and CAIC performed especially well for large sample sizes when the true model contained only one or two clusters of homogeneous mean vectors. Overall, AIC tended to be superior to SIC and CAIC for homogeneous cases when the null case was excluded and, in general, for heterogeneous cases.
Factor analysis with heteroscedastic errors
Authors: Meijer Erik , Mooijaart Ab
Published: August 2011

A factor analysis model with heteroscedastic errors is studied. Estimators are introduced that explicitly model the kind of heteroscedasticity assumed and the consequences of ignoring heteroscedasticity are indicated. These approaches are compared in a simulation study.
A geometric interpretation of the validity and reliability of difference scores
Authors: Zimmerman Donald W.
Published: August 2011

For several decades, psychometricians have been concerned about the unreliability and meagre validity of difference scores and gain scores. The present paper explores a geometric interpretation, in which observed scores are identified with vectors in a function space of random variables, and true and error components of scores are identified with orthogonal projections onto complementary subspaces. This point of view provides a simple and easily visualized geometric explanation for the widespread belief that differences are inherently unreliable. Furthermore, it discloses conditions under which difference scores are highly reliable and have substantial correlations with other measures.
Reduced Interannual Rainfall Variability in East Africa During the Last Ice Age
Authors: Wolff Christian , Haug Gerald H. , Timmermann Axel , Damsté Jaap S. Sinninghe , Brauer Achim , Sigman Daniel M. , Cane Mark A. , Verschuren Dirk
Published: August 2011

Extreme rainfall was weaker and less frequent in East Africa during the last ice age.
Glacial-Interglacial Indian Summer Monsoon Dynamics
Authors: Zhisheng An , Clemens Steven C. , Shen Ji , Qiang Xiaoke , Jin Zhangdong , Sun Youbin , Prell Warren L. , Luo Jingjia , Wang Sumin , Xu Hai , Cai Yanjun , Zhou Weijian , Liu Xiaodong , Liu Weiguo , Shi Zhengguo , Yan Libin , Xiao Xiayun , Chang Hong , Wu Feng , Ai Li , Lu Fengyan
Published: August 2011

Indian summer monsoon changes during the Pleistocene were influenced by dynamic effects originating in both hemispheres.
Exploiting Malaria Drug Resistance to Our Advantage
Authors: Cammack Nick
Published: August 2011

High-throughput chemical and gene analyses help identify promising pairs of antimalarial compounds that could prevent resistance.
Marine Census Scrambles to Fund a Second Phase With Expanded Focus
Authors: Pennisi Elizabeth
Published: August 2011

The just-completed Census of Marine Life may not be able to carry out its proposed new research agenda, called "Life in a Changing Ocean," due to lack of funding.
Targeting GLUT1 and the Warburg Effect in Renal Cell Carcinoma by Chemical Synthetic Lethality
Authors: Chan Denise A. , Sutphin Patrick D. , Nguyen Phuong , Turcotte Sandra , Lai Edwin W. , Banh Alice , Reynolds Gloria E. , Chi Jen-Tsan , Wu Jason , Solow-Cordero David E. , Bonnet Muriel , Flanagan Jack U. , Bouley Donna M. , Graves Edward E. , Denny William A. , Hay Michael P. , Giaccia Amato J.
Published: August 2011

A screen identifies a drug that specifically kills glycolysis-dependent cancer cells by inhibiting glucose uptake.
Can Anesthesia Make You Spineless?
Authors: Mashour George A.
Published: August 2011

The intravenous anesthetic propofol alters dendritic spines and synaptic organization in the neonatal cortex, raising questions about its toxicity.
Expression and Solubilization of Insect Cell-Based Rabies Virus Glycoprotein and Assessment of Its Immunogenicity and Protective Efficacy in Mice
Authors: Ramya R. , Mohana Subramanian B. , Sivakumar V. , Senthilkumar R. L. , Sambasiva Rao K. R. S. , Srinivasan V. A.
Published: August 2011

Rabies is a fatal zoonotic disease of serious public health and economic significance worldwide. The rabies virus glycoprotein (RVG) has been the major target for subunit vaccine development, since it harbors domains responsible for induction of virus-neutralizing antibodies, infectivity, and neurovirulence. The glycoprotein (G) was cloned using the baculovirus expression vector system (BEVS) and expressed inSpodoptera frugiperda(Sf-9) cells. In order to obtain a soluble form of G suitable for experimentation in mice, 18 different combinations of buffers and detergents were evaluated for their ability to solubilize the insect cell membrane-associated G. The combination that involved 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate (CHAPS) detergent in lysis buffer 1, formulated with Tris, NaCl, 10% dimethyl sulfoxide (DMSO), and EDTA, gave the highest yield of soluble G, as evidenced by the experimental data. Subsequently, several other parameters, such as the concentration of CHAPS and the duration and temperature of the treatment for the effective solubilization of G, were optimized. The CHAPS detergent, buffered at a concentration of 0.4% to 0.7% (wt/vol) at room temperature (23 to 25°C) for 30 min to 1 h using buffer 1, containing 10% DMSO, resulted in consistently high yields. The G solubilized using CHAPS detergent was found to be immunogenic when tested in mice, as evidenced by high virus-neutralizing antibody titers in sera and 100% protection upon virulent intracerebral challenge with the challenge virus standard (CVS) strain of rabies virus. The results of the mice study indicated that G solubilized with CHAPS detergent retained the immunologically relevant domains in the native conformation, thereby paving the way for producing a cell-free and efficacious subunit vaccine.
An International Collaboration To Standardize HIV-2 Viral Load Assays: Results from the 2009 ACHI
E
V
2E
Quality Control Study
Authors: Damond F. , Benard A. , Balotta Claudia , Böni Jürg , Cotten Matthew , Duque Vitor , Ferns Bridget , Garson Jeremy , Gomes Perpetua , Gonçalves Fátima , Gottlieb Geoffrey , Kupfer Bernd , Ruelle Jean , Rodes Berta , Soriano Vicente , Wainberg Mark , Taieb Audrey , Matheron Sophie , Chene Genevieve , Brun-Vezinet Francoise ,   for the ACHIV Study Group
Published: August 2011

Accurate HIV-2 plasma viral load quantification is crucial for adequate HIV-2 patient management and for the proper conduct of clinical trials and international cohort collaborations. This study compared the homogeneity of HIV-2 RNA quantification when using HIV-2 assays from ACHI
E
V
2E
study sites and either in-house PCR calibration standards or common viral load standards supplied to all collaborators. Each of the 12 participating laboratories quantified blinded HIV-2 samples, using its own HIV-2 viral load assay and standard as well as centrally validated and distributed common HIV-2 group A and B standards (
http://www.hiv.lanl.gov/content/sequence/HelpDocs/subtypes-more.html
). Aliquots of HIV-2 group A and B strains, each at 2 theoretical concentrations (2.7 and 3.7 log
10
copies/ml), were tested. Intralaboratory, interlaboratory, and overall variances of quantification results obtained with both standards were compared using
F
tests. For HIV-2 group A quantifications, overall and interlaboratory and/or intralaboratory variances were significantly lower when using the common standard than when using in-house standards at the concentration levels of 2.7 log
10
copies/ml and 3.7 log
10
copies/ml, respectively. For HIV-2 group B, a high heterogeneity was observed and the variances did not differ according to the type of standard used. In this international collaboration, the use of a common standard improved the homogeneity of HIV-2 group A RNA quantification only. The diversity of HIV-2 group B, particularly in PCR primer-binding regions, may explain the heterogeneity in quantification of this strain. Development of a validated HIV-2 viral load assay that accurately quantifies distinct circulating strains is needed.
Identification of Chemoattractive Factors Involved in the Migration of Bone Marrow-Derived Mesenchymal Stem Cells to Brain Lesions Caused by Prions
Authors: Song Chang-Hyun , Honmou Osamu , Furuoka Hidefumi , Horiuchi Motohiro
Published: August 2011

Bone marrow-derived mesenchymal stem cells (MSCs) have been reported to migrate to brain lesions of neurodegenerative diseases; however, the precise mechanisms by which MSCs migrate remain to be elucidated. In this study, we carried out an
in vitro
migration assay to investigate the chemoattractive factors for MSCs in the brains of prion-infected mice. The migration of immortalized human MSCs (hMSCs) was reduced by their pretreatment with antibodies against the chemokine receptors, CCR3, CCR5, CXCR3, and CXCR4 and by pretreatment of brain extracts of prion-infected mice with antibodies against the corresponding ligands, suggesting the involvement of these receptors, and their ligands in the migration of hMSCs. In agreement with the results of an
in vitro
migration assay, hMSCs in the corpus callosum, which are considered to be migrating from the transplanted area toward brain lesions of prion-infected mice, expressed CCR3, CCR5, CXCR3, and CXCR4. The combined
in vitro
and
in vivo
analyses suggest that CCR3, CCR5, CXCR3, and CXCR4, and their corresponding ligands are involved in the migration of hMSCs to the brain lesions caused by prion propagation. In addition, hMSCs that had migrated to the right hippocampus of prion-infected mice expressed CCR1, CX3CR1, and CXCR4, implying the involvement of these chemokine receptors in hMSC functions after chemotactic migration. Further elucidation of the mechanisms that underlie the migration of MSCs may provide useful information regarding application of MSCs to the treatment of prion diseases.
Vesicular Stomatitis Virus Expressing Tumor Suppressor p53 Is a Highly Attenuated, Potent Oncolytic Agent
Authors: Heiber Joshua F. , Barber Glen N.
Published: August 2011

Vesicular stomatitis virus (VSV), a negative-strand RNA rhabdovirus, preferentially replicates in and eradicates transformed versus nontransformed cells and is thus being considered for use as a potential anticancer treatment. The genetic malleability of VSV also affords an opportunity to develop more potent agents that exhibit increased therapeutic activity. The tumor suppressor p53 has been shown to exert potent antitumor properties, which may in part involve stimulating host innate immune responses to malignancies. To evaluate whether VSV expressing p53 exhibited enhanced oncolytic action, the murine p53 (mp53) gene was incorporated into recombinant VSVs with or without a functional viral M gene-encoded protein that could either block (VSV-mp53) or enable [VSV-M(mut)-mp53] host mRNA export following infection of susceptible cells. Our results indicated that VSV-mp53 and VSV-M(mut)-mp53 expressed high levels of functional p53 and retained the ability to lyse transformed versus normal cells. In addition, we observed that VSV-ΔM-mp53 was extremely attenuated
in vivo
due to p53 activating innate immune genes, such as type I interferon (IFN). Significantly, immunocompetent animals with metastatic mammary adenocarcinoma exhibited increased survival following treatment with a single inoculation of VSV-ΔM-mp53, the mechanisms of which involved enhanced CD49b
+
NK and tumor-specific CD8
+
T cell responses. Our data indicate that VSV incorporating p53 could provide a safe, effective strategy for the design of VSV oncolytic therapeutics and VSV-based vaccines.
Leptospiral antibodies in the breeding goat population of Poland
Authors: Czopowicz M. , Kaba J. , Smith L. , Szalus‐Jordanow O. , Nowicki M. , Witkowski L. , Frymus T.
Published: August 2011

In 2007, a survey was conducted on the prevalence of antibodies to 19 Leptospira serovars in goats in Poland. Sera were collected from adult females of all 49 breeding goat herds in Poland by applying simple random sampling. In total, 736 sera were tested by the microscopic agglutination test. A herd was considered seropositive if at least one goat with a titre of 100 or more was detected. Herd‐level seroprevalence of Leptospira was 89.8 per cent and individual‐level seroprevalence varied from less than 1.0 to 85.0 per cent among the herds. Antibodies to Leptospira serovars Zanoni, Bratislava, Autumnalis, Australis and Javanica were most frequently detected. Although 40.3 per cent of seropositive goats had high antibody titres (≥400), suggesting recent infection, no relationship with abortions or other clinical manifestation of leptospirosis in goats was detected.
Zero-mode TEM parallel-plate resonator for high-resolution thin film magnetic resonance imaging
Authors: Zhang Ziheng , Marble Andrew E. , MacGregor Rodney P. , Martin Jonathan , Wang Haijiang , Balcom Bruce J.
Published: August 2011

A parallel-plate radio frequency resonator has been designed for high-resolution thin film magnetic resonance imaging. The B1field produced by the resonator was evaluated through experiment and numerical simulation. The resonator, composed of two conductive plates sandwiching the sample, generates a uniform B1field parallel to the plates. This feature renders the resonator largely immune to radio frequency screening from conductive layers parallel to the sample. The resonator is custom fabricated according to the dimensions of the sample, yielding a high filling factor. The radio frequency probe is shown to facilitate high-sensitivity depth profiling of thin films. Three variations on the basic design are examined. Since the intention is to employ these resonators for functional studies of membranes, we introduce perforations in the parallel plates to permit mass transfer in and out of the thin films under study. One-dimensional depth profiles of Nafion 117 are presented with and without the addition of additional plates of conductive material. One-dimensional depth profiles of Nafion 1110 and a two-dimensional image of Nafion 117 in an operating fuel cell, which was integrated into the radio frequency circuit, are also illustrated.
Estimating internuclear distances between half-integer quadrupolar nuclei by central-transition double-quantum sideband NMR spectroscopy
Authors: Brinkmann Andreas , Edén Mattias
Published: August 2011

We demonstrate the estimation of homonuclear dipolar couplings, and thereby internuclear distances, between half-integer spin quadrupolar nuclei by central-transition (CT) double-quantum (2Q) sideband nuclear magnetic resonance (NMR) spectroscopy. It is shown that the rotor-encoded sideband amplitudes from CT 2Q coherences in the indirect dimension of the two-dimensional NMR spectrum are sensitive probes of the magnitude of the homonuclear dipolar coupling, but are significantly less affected by other NMR parameters such as the magnitudes and orientations of the electric field gradient tensors. Experimental results of employing the [Formula: see text] recoupling sequence to the 11B spin pair of bis(catecholato)diboron resulted in an estimation of the internuclear B–B distance as (169.6 ± 3) pm, i.e., with a relative uncertainty of ±2%, and in excellent agreement with the distance of 167.8 pm determined by single-crystal X-ray diffraction.
A new method for the synthesis of meso-brominated β-substituted porphyrins
Authors: Ali Hasrat , van Lier Johan E.
Published: August 2011

The reaction of Ni (II) complexes of etioporphyrins I, octaethylporphyrins, coproporphyrinsI tetramethylester, methyl pyrroporphyrin XXI ethylester and mesoporphyrin IX dimethyl ester derivatives with N-bromosuccinimide and triethylamine trihydrofluoride gave mono- through tetra-meso-brominated derivatives as the principal products. β-brominated products were also detected with the simultaneous loss of the β-alkyl substituents. Reaction of octaethylporphyrin Cu (II) was slow yielding meso-mono and dibromo derivatives as major products. Prolongation of the reaction time resulted in the formation of tri- and tetrabromo products substituted at both meso- and β-positions. Our results show that the central metal ion plays a major role in these bromination reactions.
Vasoactivity of the gasotransmitters hydrogen sulfide and carbon monoxide in the chicken ductus arteriosus
Authors: van der Sterren Saskia , Kleikers Pamela , Zimmermann Luc J. I. , Villamor Eduardo
Published: August 2011

Besides nitric oxide (NO) and carbon monoxide (CO), hydrogen sulfide (H2S) is a third gaseous messenger that may play a role in controlling vascular tone and has been proposed to serve as an O2 sensor. However, whether H2S is vasoactive in the ductus arteriosus (DA) has not yet been studied. We investigated, using wire myography, the mechanical responses induced by Na2S (1 μM–1 mM), which forms H2S and HS− in solution, and by authentic CO (0.1 μM-0.1 mM) in DA rings from 19-day chicken embryos. Na2S elicited a 100% relaxation (pD2 4.02) of 21% O2-contracted and a 50.3% relaxation of 62.5 mM KCl-contracted DA rings. Na2S-induced relaxation was not affected by presence of the NO synthase inhibitor l-NAME, the soluble guanylate cyclase (sGC) inhibitor ODQ, or the K+ channel inhibitors tetraethylammonium (TEA; nonselective), 4-aminopyridine (4-AP, KV), glibenclamide (KATP), iberiotoxin (BKCa), TRAM-34 (IKCa), and apamin (SKCa). CO also relaxed O2-contracted (60.8% relaxation) and KCl-contracted (18.6% relaxation) DA rings. CO-induced relaxation was impaired by ODQ, TEA, and 4-AP (but not by l-NAME, glibenclamide, iberiotoxin, TRAM-34 or apamin), suggesting the involvement of sGC and KV channel stimulation. The presence of inhibitors of H2S or CO synthesis as well as the H2S precursor l-cysteine or the CO precursor hemin did not significantly affect the response of the DA to changes in O2 tension. Endothelium-dependent and -independent relaxations were also unaffected. In conclusion, our results indicate that the gasotransmitters H2S and CO are vasoactive in the chicken DA but they do not suggest an important role for endogenous H2S or CO in the control of chicken ductal reactivity.
Octreotide-Treated Diabetes Accompanied by Endogenous Hyperinsulinemic Hypoglycemia and Protein-Losing Gastroenteropathy
Authors: Takahashi Nobuhiko , Nagamine Miho , Fukuda Mitsuko , Motomura Wataru , Abiko Atsuko , Haneda Masakazu , Fujiya Mikihiro , Ieko Masahiro , Kohgo Yutaka
Published: August 2011

Occurrence of hypoglycemia in diabetes patients is very rare. We report here a case of frequent hypoglycemic attacks caused by inappropriate endogenous hyperinsulinemia in a female patient with poorly controlled diabetes and protein-losing gastroenteropathy. The blood glucose profiles of the patient were unstable. Results of the fasting test performed to investigate the cause of hypoglycemia suggested endogenous hyperinsulinism. Repeated selective arterial calcium injection tests suggested that hyperinsulinemia might be extrapancreatic in origin. However, efforts to detect a responsible lesion such as insulinoma were unsuccessful. Octreotide was used for the treatment of hypoglycemia and protein-losing gastroenteropathy. After treatment, although her leg edema caused by hypoalbuminemia persisted, hypoglycemia almost disappeared.
A Statistical Approach to the Forward Kinematics Nonlinearity Analysis of Gough‐Stewart Mechanism
Authors: Karimi Davoud , Nategh Mohammad Javad
Published: August 2011

Both the forward and backward kinematics of the Gough‐Stewart mechanism exhibit nonlinear
behavior. It is critically important to take account of this nonlinearity in some applications such
as path control in parallel kinematics machine tools. The nonlinearity of inverse kinematics is
straightforward and has been first studied in this paper. However the nonlinearity of forward
kinematics is more challenging to be considered as there is no analytic solution to the forward
kinematic solution of the mechanism. A statistical approach including the Bates and Watts
measures of nonlinearity has been employed to investigate the nonlinearity of the forward
kinematics. The concept of standard sphere has been used to check the significance of the
nonlinearity of the mechanism. It is demonstrated that the length of the region, defined as the
linear approximation of the lifted line, has a significant impact on the nonlinearity of the
mechanism.
Probucol Attenuates Oxidative Stress, Energy Starvation, and Nitric Acid Production Following Transient Forebrain Ischemia in the Rat Hippocampus
Authors: Al-Majed Abdulhakeem A.
Published: August 2011

Oxidative stress and energy depletion are believed to participate in hippocampal neuronal damage after forebrain ischemia. This study has been initiated to investigate the potential neuroprotective effects of probucol, a lipid-lowering drug with strong antioxidant properties, against transient forebrain ischemia-induced neuronal damage and biochemical abnormalities in rat hippocampal CA1 region. Adult male Wistar albino rats were subjected to forebrain ischemia and injected with probucol for the next 7 successive days, and compared to controls. Forebrain ischemia resulted in a significant decrease in the number of intact neurons (77%), glutathione (GSH), and adenosine triphosphate (ATP), and a significant increase in thiobarbituric acid reactive substances (TBARS) and total nitrate/nitrite, (NOx) production in hippocampal tissues. The administration of probucol attenuated forebrain ischemia-induced neuronal damage, manifested as a complete reversal of the decrease in the number of intact neurons, ATP and GSH and the increase in TBARS and NOxin hippocampal tissues. This study demonstrates that probucol treatment abates forebrain ischemia-induced hippocampal neuronal loss, energy depletion, and oxidative stress in hippocampal CA1 region. Thus, probucol could be a promising neuroprotective agent in the treatment of forebrain ischemia.
Weighted Composition Operators and Supercyclicity Criterion
Authors: Yousefi Bahmann , Izadi Javad
Published: August 2011

We consider an equivalent condition to the property
of Supercyclicity Criterion, and then we investigate this property for the adjoint of weighted composition operators acting on Hilbert spaces of analytic functions.
Strong Convergence by a Hybrid Algorithm for Finding a Common Fixed Point of Lipschitz Pseudocontraction and Strict Pseudocontraction in Hilbert Spaces
Authors: Ungchittrakool Kasamsuk
Published: August 2011

We prove a strong convergence theorem by using a hybrid algorithm in order to find a common
fixed point of Lipschitz pseudocontraction and κ‐strict pseudocontraction in Hilbert spaces. Our results extend the
recent ones announced by Yao et al. (2009) and many others.
Biological and Spectral Studies of Newly Synthesized Triazole Schiff Bases and Their Si(IV), Sn(IV) Complexes
Authors: Singh Kiran , Puri Parvesh , Kumar Yogender , Sharma Chetan , Aneja Kamal Rai
Published: August 2011

The Schiff bases HL1-3have been prepared by the reaction of 5-bromothiophene-2-carboxaldehyde with 4-amino-5-mercapto-3-methyl/propyl/isopropyl-s-triazole, respectively. Organosilicon(IV) and organotin(IV) complexes of formulae (CH3)2MCl(L1-3), (CH3)2M(L1-3)2were synthesized from the reaction of (CH3)2MCl2and the Schiff bases in 1 : 1 and 1 : 2 molar ratio, where and Sn. The synthesized Schiff bases and their metal complexes have been characterized with the aid of various physicochemical techniques like elemental analyses, molar conductance, UV, IR,1H,13C,29Si, and119Sn NMR spectroscopy. Based on these studies, the trigonal bipyramidal and octahedral geometries have been proposed for these complexes. The ligands and their metal complexes have been screenedin vitroagainst some bacteria and fungi.
Molecular Mechanisms Underlying Activity-Dependent GABAergic Synapse Development and Plasticity and Its Implications for Neurodevelopmental Disorders
Authors: Chattopadhyaya Bidisha
Published: August 2011

GABAergic interneurons are critical for the normal function and development of neural circuits, and their dysfunction is implicated in a large number of neurodevelopmental disorders. Experience and activity-dependent mechanisms play an important role in GABAergic circuit development, also recent studies involve a number of molecular players involved in the process. Emphasizing the molecular mechanisms of GABAergic synapse formation, in particular basket cell perisomatic synapses, this paper draws attention to the links between critical period plasticity, GABAergic synapse maturation, and the consequences of its dysfunction on the development of the nervous system.
Iron-Fortified Drinking Water Studies for the Prevention of Children's Anemia in Developing Countries
Authors: Dutra-de-Oliveira Jose E. , Marchini J. Sergio , Lamounier Joel , Almeida Carlos A. N.
Published: August 2011

Anemia and iron deficiency should receive special attention considering their high prevalence and serious consequences. For prevention, globally it is recommended to increase dietary iron intake, iron fortification of industrialized foods, and medical iron supplementation. Food fortification for the prevention of iron deficiency in developing countries should consider carriers locally available and consumed daily, requiring limited infrastructure and technology. Drinking water is the iron carrier we have been working for years for the prevention of iron deficiency and anemia in small children in Brazil. It was shown that studies with iron-fortified drinking water were proved to be effective on children's anemia prevention. Water is found everywhere, consumed daily by everyone may be easily fortified with simple technology, is low priced and was effective on the prevention of children's anemia. Fortification of drinking water with iron was locally implemented with the direct participation of the government and community. Government authorities, health personnel and population were part of the project and responsible for its community implementation. The mayor/municipality permitted and supported the proposal to supply it to children at their day-care centers. To keep the children drinking water iron fortified supply an officially authorized legislation was also approved.
Relationship between Depressive Symptoms and Cardiovascular Disease Risk Factors in African American Individuals
Authors: Weinstein Ali A. , Abraham Preetha , Diao Guoqing , Zeno Stacey A. , Deuster Patricia A.
Published: August 2011

Objective. To examine the relationship between depressive symptoms and cardiovascular disease (CVD) risk factors in a group of African American individuals.Design. A nonrandom sample of 253 (age 43.7 ± 11.6 years; 37% male) African American individuals was recruited by advertisements. Data were obtained by validated questionnaires, anthropometric, blood pressure, and blood sample measurements.Results. Regression analyses were performed to assess the relationship between depressive symptoms and CVD risk factors controlling for socioeconomic status indicators. These analyses demonstrated that those with higher levels of depressive symptoms had larger waist-to-hip ratios, higher percent body fat, higher triglycerides, and were more likely to be smokers.Conclusions. It has been well documented that higher levels of depressive symptoms are associated with higher CVD risk. However, this evidence is derived primarily from samples of predominantly Caucasian individuals. The present investigation demonstrates that depressive symptoms are related to CVD risk factors in African American individuals.
Characterization of a Cleavage Stimulation Factor, 3′ pre-RNA, Subunit 2, 64 kDa (CSTF2) as a Therapeutic Target for Lung Cancer
Authors: Aragaki Masato , Takahashi Koji , Akiyama Hirohiko , Tsuchiya Eiju , Kondo Satoshi , Nakamura Yusuke , Daigo Yataro
Published: August 2011

Purpose: This study aims to discover novel biomarkers and therapeutic targets for lung cancers.

Experimental Design: We screened for genes showing elevated expression in the majority of lung cancers by genome-wide gene expression profile analysis of 120 lung cancers obtained by cDNA microarray representing 27,648 genes or expressed sequence tags. In this process, we detected a gene encoding cleavage stimulation factor, 3′ pre-RNA, subunit 2, 64 kDa (CSTF2) as a candidate. Immunohistochemical staining using tissue microarray consisting of 327 lung cancers was applied to examine the expression of CSTF2 protein and its prognostic value. A role of CSTF2 in cancer cell growth was examined by siRNA experiments.

Results: Northern blot and immunohistochemical analyses detected the expression of CSTF2 only in testis among 16 normal tissues. Immunohistochemical analysis using tissue microarray showed an association of strong CSTF2 expression with poor prognosis of patients with non–small cell lung cancer (P = 0.0079), and multivariate analysis showed that CSTF2 positivity is an independent prognostic factor. In addition, suppression of CSTF2 expression by siRNAs suppressed lung cancer cell growth, whereas exogenous expression of CSTF2 promoted growth and invasion of mammalian cells.

Conclusions: CSTF2 is likely to play an important role in lung carcinogenesis and be a prognostic biomarker in the clinic. Clin Cancer Res; 17(18); 5889–900. ©2011 AACR.
Comparing Aye-Aye (Daubentonia madagascariensis) Presence and Distribution between Degraded and Non-Degraded Forest within Ranomafana National Park, Madagascar
Authors: Farris Zach J. , Morelli Toni Lyn , Sefczek Timothy , Wright Patricia C.
Published: August 2011

The aye-aye is considered the most widely distributed lemur in Madagascar; however, the effect of forest quality on aye-aye abundance is unknown. We compared aye-aye presence across degraded and non-degraded forest at Ranomafana National Park, Madagascar. We used secondary signs (feeding sites, high activity sites) as indirect cues of aye-aye presence andCanariumtrees as an indicator of resource availability. All 3 measured variables indicated higher aye-aye abundance within non-degraded forest; however, the differences across forest type were not significant. Both degraded and non-degraded forests showed a positive correlation between feeding sites and high activity sites. We found thatCanarium, an important aye-aye food source, was rare and had limited dispersal, particularly across degraded forest. This preliminary study provides baseline data for aye-aye activity and resource utilization across degraded and non-degraded forests.