bluuebunny/crossref_metadata_2025 huggingface dataset:
The proprioceptive and agonist roles of gastrocnemius, soleus and tibialis anterior muscles in maintaining human upright posture
Authors: Di Giulio Irene , Maganaris Constantinos N. , Baltzopoulos Vasilios , Loram Ian D.
Published: March 2009

Humans can stand using sensory information solely from the ankle muscles. Muscle length and tension in the calf muscles (gastrocnemius and soleus) are unlikely to signal postural sways on account of balance‐related modulation in agonist activity. These facts pose two questions: (1) Which ankle muscles provide the proprioceptive information? (2) Which peripheral mechanism could modulate agonist activity? To address these issues, subjects were asked to stand normally on two force plates. Ultrasound and surface EMG were recorded from the calf and tibialis anterior (TA) muscles. For all nine subjects, changes in muscle length of TA were mainly (84 ± 9% whole trial duration) orthodoxly correlated with bodily sway (centre of gravity, CoG), i.e. in accordance with passive ankle rotation. When orthodox, TA had the highest correlation with CoG (−0.66 ± 0.07, deep compartment, P < 0.001). For five subjects, the superficial TA compartment showed counter‐intuitive changes in muscle length with CoG, probably due to the flattening of the foot and proximal attachment geometry. Gastrocnemius and soleus were usually (duration 71 ± 23 and 81 ± 16%, respectively) active agonists (paradoxically correlated with CoG) but, for short periods of time, they could be orthodox and then presented a moderate correlation (0.38 ± 0.16 and 0.28 ± 0.09, respectively) with CoG. Considering the duration and extent to which muscle length is orthodox and correlated with CoG, TA may be a better source of proprioceptive information than the active agonists (soleus and gastrocnemius). Therefore, if a peripheral feedback mechanism modulates agonist activity then reciprocal inhibition acted by TA on the calf muscles is more likely to be effective than the autogenic pathway.
Sensitization of lamina I spinoparabrachial neurons parallels heat hyperalgesia in the chronic constriction injury model of neuropathic pain
Authors: Andrew David
Published: March 2009

It has been proposed that spinal lamina I neurons with ascending axons that project to the midbrain play a crucial role in hyperalgesia. To test this hypothesis the quantitative properties of lamina I spinoparabrachial neurons in the chronic constriction injury (CCI) model of neuropathic pain were compared to those of unoperated and sham‐operated controls. Behavioural testing showed that animals with a CCI exhibited heat hyperalgesia within 4 days of the injury, and this hyperalgesia persisted throughout the 14‐day post‐operative testing period. In the CCI, nociceptive lamina I spinoparabrachial neurons had heat thresholds that were significantly lower than controls (43.0 ± 2.8°C vs. 46.7 ± 2.6°C; P < 10−4, ANOVA). Nociceptive lamina I spinoparabrachial neurons were also significantly more responsive to graded heat stimuli in the CCI, compared to controls (P < 0.02, 2‐factor repeated‐measures ANOVA), and increased after‐discharges were also observed. Furthermore, the heat‐evoked stimulus–response functions of lamina I spinoparabrachial neurons in CCI animals co‐varied significantly (P < 0.03, ANCOVA) with the amplitude of heat hyperalgesia determined behaviourally. Taken together these results are consistent with the hypothesis that lamina I spinoparabrachial neurons have an important mechanistic role in the pathophysiology of neuropathic pain.
The Momedemameter: An Affordable Pre-Eclampsia Detector for Low Resource Environments
Authors: Pawluk Dianne , Burch David , Strauss Jerome F. , Peng Thomas , Woodward Ashley
Published: March 2009

Pre-eclampsia, a pregnancy-specific disorder, is the third leading cause of maternal morbidity and mortality worldwide. To develop a device to detect pre-eclampsia in pregnant women living in low resource environments, a method was needed that had to be very low cost and, preferably, easily monitored by the woman herself. Due to the high cost and expertise involved in monitoring the two diagnostic criteria of pre-eclampsia (elevated blood pressure and proteinuria), edema, an indicator of pre-eclampsia, was chosen instead. The general principle of the method is to have each pregnant woman, early in pregnancy, fitted, on either her wrist or ankle, with a detection band, which is set to a preset expansion limit (e.g., expansion by 5%). When edema causes that body part to swell to the limit, the pregnant mother knows that she should seek medical assistance. The resulting prototype device and calibration method require little knowledge and are very durable, cost-effective, and portable.
Inhaled Voriconazole for Prevention of Invasive Pulmonary Aspergillosis
Authors: Tolman Justin A. , Wiederhold Nathan P. , McConville Jason T. , Najvar Laura K. , Bocanegra Rosie , Peters Jay I. , Coalson Jacqueline J. , Graybill John R. , Patterson Thomas F. , Williams Robert O.
Published: March 2009

Targeted airway delivery of antifungals as prophylaxis against invasive aspergillosis may lead to high lung drug concentrations while avoiding toxicities associated with systemically administered agents. We evaluated the effectiveness of aerosolizing the intravenous formulation of voriconazole as prophylaxis against invasive pulmonary aspergillosis caused by
Aspergillus fumigatus
in an established murine model. Inhaled voriconazole significantly improved survival and limited the extent of invasive disease, as assessed by histopathology, compared to control and amphotericin B treatments.
Designing Therapies against Experimental Visceral Leishmaniasis by Modulating the Membrane Fluidity of Antigen-Presenting Cells
Authors: Banerjee Subha , Ghosh June , Sen Subha , Guha Rajan , Dhar Ranjan , Ghosh Moumita , Datta Sanchita , Raychaudhury Bikramjit , Naskar Kshudiram , Haldar Arun Kumar , Lal C. S. , Pandey K. , Das V. N. R. , Das Pradeep , Roy Syamal
Published: March 2009

The membrane fluidity of antigen-presenting cells (APCs) has a significant bearing on T-cell-stimulating ability and is dependent on the cholesterol content of the membrane. The relationship, if any, between membrane fluidity and defective cell-mediated immunity in visceral leishmaniasis has been investigated. Systemic administration of cholesterol by liposome delivery (cholesterol liposomes) inLeishmania donovani-infected hamsters was found to cure the infection. Splenic macrophages as a prototype of APCs in infected hamsters had decreased membrane cholesterol and an inability to drive T cells, which was corrected by cholesterol liposome treatment. The effect was cholesterol specific because liposomes made up of the analogue 4-cholesten-3-one provided almost no protection. Infection led to increases in interleukin-10 (IL-10), transforming growth factor beta, and IL-4 signals and concomitant decreases in gamma interferon (IFN-γ), tumor necrosis factor alpha, and inducible NO synthase signals, which reverted upon cholesterol liposome treatment. The antileishmanial T-cell repertoire, whose expansion appeared to be associated with protection, was presumably type Th1, as shown by enhanced IFN-γ signals and the predominance of the immunoglobulin G2 isotype. The protected group produced significantly more reactive oxygen species and NO than the infected groups, which culminated in killing ofL. donovaniparasites. Therefore, cholesterol liposome treatment may be yet another simple strategy to enhance the cell-mediated immune response toL. donovaniinfection. To our knowledge, this is the first report on the therapeutic effect of cholesterol liposomes in any form of the disease.
Genetics and Virulence Association of the
Shigella flexneri
Sit Iron Transport System
Authors: Fisher Carolyn R. , Davies Nicola M. L. L. , Wyckoff Elizabeth E. , Feng Zhengyu , Oaks Edwin V. , Payne Shelley M.
Published: March 2009

The
sit
-encoded iron transport system is present within pathogenicity islands in all
Shigella
spp. and some pathogenic
Escherichia coli
strains. The islands contain numerous insertion elements and sequences with homology to bacteriophage genes. The
Shigella flexneri sit
genes can be lost as a result of deletion within the island. The formation of deletions was dependent upon RecA and occurred at relatively high frequency. This suggests that the
sit
region is inherently unstable, yet
sit
genes are maintained in all of the clinical isolates tested. Characterization of the
sitABCD
genes in
S. flexneri
indicates that they encode a ferrous iron transport system, although the genes are induced aerobically. The
sit
genes provide a competitive advantage to
S. flexneri
growing within epithelial cells, and a
sitA
mutant is outcompeted by the wild type in cultured epithelial cells. The Sit system is also required for virulence in a mouse lung model. The
sitA
mutant was able to infect the mice and induce a protective immune response but was avirulent compared to its wild-type parent strain.
Biodiversity of Trichoderma strains in Tunisia
Authors: Sadfi-Zouaoui N. , Hannachi I. , Rouaissi M. , Hajlaoui M. R. , Rubio M. B. , Monte E. , Boudabous A. , Hermosa M. R.
Published: March 2009

Trichoderma strains were sampled in 4 different bioclimatic zones of Tunisia, a Mediterranean North African country with strong climatic and edaphic variability from north to south, to assess the genetic diversity of endemic species of Trichoderma and their relationship to the bioclimatic zones. In all, 53 strains were isolated and identified at the species level by analysis of their internal transcribed spacers regions 1 and 2 (ITS1 and ITS2) of the rDNA cluster and (or) a fragment of the translation elongation factor 1 (tef1) gene, using an online interactive key for species identification in Trichoderma and ex-type strains and taxonomically established isolates of Trichoderma as references. At least 2 different species were observed in each ecosystem. Trichoderma harzianum clade VI and Trichoderma longibrachiatum were present in forest soils in north Tunisia; Trichoderma atroviride and Trichoderma hamatum were found in cultivated fields in northeast Tunisia; T. harzianum clade VI, a Trichoderma sp. close to the T. harzianum complex, and Trichoderma saturnisporum were isolated from forest soils in central Tunisia; and T. harzianum clade II and T. hamatum were present in oasis soils in south Tunisia.
Effect of biofumigation with volatiles from Muscodor albus on the viability of Tilletia spp. teliospores
Authors: Goates Blair J. , Mercier Julien
Published: March 2009

Volatile organic compounds produced by the fungus Muscodor albus inhibit or kill numerous fungi. The effect of these volatiles was tested on dormant and physiologically active teliospores of the smut fungi Tilletia horrida , Tilletia indica , and Tilletia tritici , which cause kernel smut of rice, Karnal bunt of wheat, and common bunt of wheat, respectively. Reactivated rye grain culture of M. albus was used to fumigate dormant teliospores in dry Petri dishes and physiologically active teliospores on water agar for up to 5 days at 22 °C. Teliospores of all 3 species were incapable of germination when fumigated on agar for 5 days. When T. tritici on agar was fumigated only during the initial 48 h of incubation, viability was reduced by 73%–99%. Fumigation of dry loose teliospores of T. tritici caused a 69%–97% loss in viability, whereas teliospores within intact sori were not affected. Dormant teliospores of T. horrida and T. indica were not affected by M. albus volatiles. It appears that M. albus has potential as a seed or soil treatment for controlling seedling-infecting smuts where infection is initiated by germinating teliospores prior to seedling emergence. The volatiles were not effective for postharvest control of teliospores under conditions used in these experiments.
Entry of dengue virus serotype 2 into ECV304 cells depends on clathrin-dependent endocytosis, but not on caveolae-dependent endocytosis
Authors: Peng Tao , Wang Jia-Li , Chen Wei , Zhang Jun-Lei , Gao Na , Chen Zong-Tao , Xu Xiao-Feng , Fan Dong-Ying , An Jing
Published: March 2009

Caveolae- and clathrin-mediated endocytosis are major internalization pathways used by several pathogens; however, their distinctive roles in dengue virus (DV) entry have not been addressed. In this study, we compared the involvement of caveolae- and clathrin-mediated endocytosis in the infectious entry of DV serotype 2 (DV2) into human endothelial-like ECV304 cells. Confocal microscopy study on DV2-infected cells showed that viral antigens were co-localized with clathrin heavy chains, epidermal growth factor pathway substrate clone 15 (Eps15), and adaptin-α, but not with caveolin-1. Treatment with chlorpromazine, which inhibits clathrin-dependent endocytosis, led to reduced virus entry into cells, whereas treatment with nystatin, a caveolae inhibitory agent, did not. Furthermore, gene silencing of Eps15 resulted in an average of 75% reduced infection of ECV304 cells by DV2. Our results demonstrated that DV2 enters ECV304 cells by clathrin-dependent endocytosis, not by caveolae-dependent endocytosis.
In vivo associations of Escherichia coli NarJ with a peptide of the first 50 residues of nitrate reductase catalytic subunit NarG
Authors: Li Haiming , Turner Raymond J.
Published: March 2009

The catalytic subunit of many Escherichia coli redox enzymes bares a twin-arginine translocation (Tat)-dependent signal peptide in its precursor, which directs the redox enzyme complex to this Sec-independent pathway. NarG of the E. coli nitrate reductase NarGHI complex possesses a vestige twin-arginine motif at its N terminus. During the cofactor insertion, and assembly and folding of the NarG–NarH complex, a chaperone protein, NarJ, is thought to interact with the N terminus and an unknown second site of NarG. Our previous in vitro study provided evidence that NarJ’s role shows some Tat system dependence. In this work, we investigated the associations of NarJ with a peptide of the first 50 residues of NarG (NarG50) in living cells. Two approaches were used: the Förster resonance energy transfer (FRET) based on yellow fluorescent protein – cyan fluorescent protein (YFP–CFP) and the bimolecular fluorescence complementation (BiFC). Compared with the wild-type (WT) E. coli cotransformants expressing both NarJ–YFP and NarG50–CFP, tat gene mutants gave an apparent FRET efficiency (Eapp) that was on the order of 25%–40% lower. These experiments implied a Tat system dependency of the in vivo associations between NarJ and the NarG50 peptide. In the BiFC assay, a 4-fold lower specific fluorescence intensity was observed for the E. coli WT cotransformants expressing both NarJ–Yc and NarG50–Yn than for its tat mutants, again suggesting a Tat dependence of the interactions. Fluorescence microscopy showed a “dot”/unipolar distribution of the reassembled YFP–NarJ:NarG50 both in WT and tat mutants, demonstrating a distinct localization of the interaction. Thus, although the degree of the interaction shows Tat dependence, the cell localization is less so. Taken together, these data further support that NarJ’s activity on NarG may be assisted by the Tat system.
Comparison of anorexia, lethargy, and fever induced by bacterial and viral mimetics in rats
Authors: Hopwood Nicola , Maswanganyi Tlangelani , Harden Lois M.
Published: March 2009

Although it has been established that some acute phase responses present differently depending on whether a virus or bacteria activates the innate immune system, it has not yet been established whether fever and sickness behaviors, such as anorexia and lethargy, present differently. We therefore investigated the effects of administering lipopolysaccharide (LPS) and polyinosinic : polycytidylic acid (poly I:C) on body temperature, food intake, body mass, and activity (cage activity and wheel running). Male Sprague–Dawley rats were randomly assigned to receive an intraperitoneal injection of one of LPS (75 µg/kg or 250 µg/kg), poly I:C (3000 µg/kg or 4000 µg/kg), or saline. Administration of LPS or poly I:C induced fever, anorexia, and lethargy. Although voluntary wheel running and cage activity were both significantly reduced after administration of LPS or poly I:C, they were not affected equally. Indeed voluntary wheel running was decreased on average by approximately 30% more than cage activity regardless of the dose or type of mimetic administered. Our results indicate that poly I:C is less effective at inducing anorexia, lethargy, and fever in rats than is LPS, and that avoidance of exercise in animals and humans during infection is likely to be a more prominent feature of illness than is avoidance of routine daily activity.
Do interlinks between geography and ecology explain the latitudinal diversity patterns in Sciuridae? An approach at the genus level
Authors: Amori Giovanni , Gippoliti Spartaco , Luiselli Luca , Battisti Corrado
Published: March 2009

The latitudinal gradient theory explains the uneven distribution of taxa richness across the world. We explore this theory using genera of Sciuridae (Mammalia: Rodentia). Distribution data for each genus were obtained from literature and mapped with the WorldMap program. The two hemispheres were subdivided into 23 latitudinal bands of equal area. As the total number of genera in each latitudinal band was influenced by the different available area, data were normalized prior to analyses. Then, genera density of each latitudinal band was correlated with latitude, and the ratio of genera richness of each guild to total genera richness was calculated for each latitudinal band. Total genus density was significantly correlated with flying squirrel density and terrestrial squirrel density in both hemispheres, and these two genera densities were significantly correlated with each other in the northern hemisphere. The guilds showed clear vicariance patterns. The total diversity of genera of Sciuridae was inversely correlated to latitude. The increase of genera towards tropical northern hemisphere was due to the progressive increase of the tree and flying squirrel genera. Change in biomes (tundra vs. forests) is likely responsible for the increase in the tree squirrel component at these latitudes. Overall, our study confirmed assumptions of the latitudinal gradient theory.
QUANTITATIVE CALCULATIONS FOR BLACK HOLE PRODUCTION AT THE LARGE HADRON COLLIDER
Authors: BOCK NICOLAS , HUMANIC THOMAS J.
Published: March 2009

The framework of large extra dimensions provides a way to explain why gravity is weaker than the other forces in nature. A consequence of this model is the possible production of D-dimensional black holes in high energy p–p collisions at the Large Hadron Collider. The present work uses the CATFISH black hole generator to study quantitatively how these events could be observed in the hadronic channel at midrapidity using a particle-tracking detector.
STRUCTURE FUNCTIONS
Authors: DIACONU CRISTINEL
Published: March 2009

Recent progress in the understanding of the nucleon is presented. The unpolarized structure functions are obtained with unprecedented precision from the combined H1 and ZEUS data and are used to extract proton parton distribution functions via NLO QCD fits. The obtained parametrization displays an improved precision, in particular at low Bjorken x, and leads to precise predictions of cross-sections for LHC phenomena. Recent data from proton–antiproton collisions at Tevatron indicate further precise constraints at large Bjorken x. The flavor content of the proton is further studied using final states with charm and beauty in DIS ep and [Formula: see text] collisions. Data from polarized DIS or proton–proton collisions are used to test the spin structure of the proton and to constrain the polarized parton distributions.
ORBITALLY STABLE STATES IN GENERALIZED HARTREE–FOCK THEORY
Authors: DOLBEAULT JEAN , FELMER PATRICIO , LEWIN MATHIEU
Published: March 2009

This paper is devoted to a generalized Hartree–Fock model in the Euclidean space. For large classes of free energy functionals, minimizers are obtained as long as the total charge of the system does not exceed a threshold which depends on a parameter that we call the temperature in analogy with models based on a thermodynamical approach. The usual Hartree–Fock model is recovered in the zero temperature limit. An orbital stability result for the Cauchy problem is deduced from the variational approach.
DIFFERENCES BETWEEN NORMAL AND SHUFFLED TEXTS: STRUCTURAL PROPERTIES OF WEIGHTED NETWORKS
Authors: MASUCCI A. P. , RODGERS G. J.
Published: March 2009

In this paper we deal with the structural properties of weighted networks. Starting from an empirical analysis of a linguistic network, we analyze the differences between the statistical properties of a real and a shuffled network. We show that the scale-free degree distribution and the scale-free weight distribution are induced by the scale-free strength distribution, that is Zipf's law. We test the result on a scientific collaboration network, that is a social network, and we define a measure – the vertex selectivity – that can distinguish a real network from a shuffled network. We prove, via an ad hoc stochastic growing network with second order correlations, that this measure can effectively capture the correlations within the topology of the network.
DELAY-INDEPENDENT STABILITY OF GENETIC REGULATORY NETWORKS WITH TIME DELAYS
Authors: WU FANG-XIANG
Published: March 2009

In an organism, genes encode proteins, some of which in turn regulate other genes. Such interactions work in highly structured but incredibly complex ways, and make up a genetic regulatory network. Recently, nonlinear delay differential equations have been proposed for describing genetic regulatory networks in the state-space form. In this paper, we study stability properties of genetic regulatory networks with time delays, by the notion of delay-independent stability. We first present necessary and sufficient conditions for delay-independent local stability of genetic regulatory networks with a single time delay, and then extend the main result to genetic regulatory networks with multiple time delays. To illustrate the main theory, we analyze delay-independent stability of three genetic regulatory networks in E. coli or zebra fish. For E. coli, an autoregulatory network and a repressilatory network are analyzed. The results show that these two genetic regulatory networks with parameters in the physiological range are delay-independently robustly stable. For zebra fish, an autoregulatory network for the gene her1 is analyzed. The result shows that delay-independent stability of this network depends on the initial number of protein molecules, which is in agreement with the existing biological knowledge. The theories presented in this paper provide a very useful complement to the previous work and a framework for further studying the stability of more complex genetic regulatory networks.
NECESSARY BACKBONE OF SUPERHIGHWAYS FOR TRANSPORT ON GEOGRAPHICAL COMPLEX NETWORKS
Authors: HAYASHI YUKIO
Published: March 2009

Many real networks have a common topological structure called scale-free (SF) that follows a power law degree distribution, and are embedded on an almost planar space which is suitable for wireless communication. However, the geographical constraints on local cycles cause more vulnerable connectivity against node removals, whose tolerance is reduced from the theoretical prediction under the assumption of uncorrelated locally tree-like structure. We consider a realistic generation of geographical networks with the SF property, and show the significant improvement of the robustness by adding a small fraction of shortcuts between randomly chosen nodes. Moreover, we quantitatively investigate the contribution of shortcuts to transport many packets on the shortest path for the spatially different amount of communication requests. Such a shortcut strategy preserves topological properties and a backbone naturally emerges bridging isolated clusters.
ENGINEERING MANAGEMENT IN DEVELOPING ECONOMIES: THE EMIDE APPROACHES TO MEET THE NEW CHALLENGES
Authors: CHANG C. M.
Published: March 2009

The pace of globalization is accelerating. It has been forecast that the Gross Domestic Products of the BRIC nations are expected to surpass those of the G6 countries by 2038. Regional economies will change rapidly, suggesting that engineering managers in the East will need to take different approaches to achieve success in the marketplace. This paper outlines five specific approaches, which constitute the EMIDE model, for engineering managers in the East to customize their engineering management practices, in order to capture these new growth opportunities, to expand beyond their local regions and to meet the challenges ahead.
L2 CASTELNUOVO–DE FRANCHIS, THE CUP PRODUCT LEMMA, AND FILTERED ENDS OF KÄHLER MANIFOLDS
Authors: NAPIER TERRENCE , RAMACHANDRAN MOHAN
Published: March 2009

Simple approaches to the proofs of the L2 Castelnuovo–de Franchis theorem and the cup product lemma which give new versions are developed. For example, assume that ω1 and ω2 are two linearly independent closed holomorphic 1-forms on a bounded geometry connected complete Kähler manifold X with ω2 in L2. According to a version of the L2 Castelnuovo–de Franchis theorem obtained in this paper, if ω1 ∧ ω2 ≡ 0, then there exists a surjective proper holomorphic mapping of X onto a Riemann surface for which ω1 and ω2 are pull-backs. Previous versions required both forms to be in L2.
A numerical evaluation of preprocessing and ILU-type preconditioners for the solution of unsymmetric sparse linear systems using iterative methods
Authors: Mayer Jan
Published: March 2009

Recent advances in multilevel LU factorizations and novel preprocessing techniques have led to an extremely large number of possibilities for preconditioning sparse, unsymmetric linear systems for solving with iterative methods. However, not all combinations work well for all systems, so making the right choices is essential for obtaining an efficient solver. The numerical results for 256 matrices presented in this article give an indication of which approaches are suitable for which matrices (based on different criteria, such as total computation time or fill-in) and of the differences between the methods.
Algorithm 893
Authors: Renka Robert J.
Published: March 2009

TSPACK is a curve-fitting package based on exponential tension splines with automatic selection of tension factors. It serves both as a method for data fitting with preservation of shape properties or more general constraints, and as a means of computer aided geometric design of curves in two or three dimensions. The package is based on a translation of Algorithm 716 from Fortran 77 into MATLAB. The translation includes bug corrections, vectorization where possible, and extensions, including a B-spline representation, designed to facilitate curve design as opposed to data fitting. An interactive graphical user interface, not part of the algorithm, is available from the author.
Detoxification and Endothelialization of Glutaraldehyde-Fixed Bovine Pericardium With Titanium Coating
Authors: Guldner Norbert W. , Jasmund Inka , Zimmermann Hanngörg , Heinlein Markus , Girndt Britta , Meier Veronika , Flüß Florian , Rohde Daniel , Gebert Andreas , Sievers Hans-Hinrich
Published: March 2009

Background—

Endothelial cell seeding of glutardialdehyde-fixed biological heart valves is hypothesized to improve biocompatibility and durability; however, the toxicity of glutardialdehyde prevents its use as a biological coating. Therefore, different detoxification strategies are applied, including surface coating with titanium, before in vitro endothelialization of glutaraldehyde-fixed bovine pericardium as the base material for prosthetic heart valves.

Methods and Results—

Bovine pericardium was fixed with 0.25% glutardialdehyde. Detoxification was performed with citric acid, aldehyde dehydrogenase, and plasma deposition with titanium at low temperatures of 30°C to 35°C. Toxic glutaraldehyde ligands were quantified photometrically, and the vitality of seeded cells was tested to validate detoxification methods. Detoxification agents and titanium coating were applied before seeding with human endothelial cells. Endothelial cells were visualized by electron microscopic surface scanning. To evaluate cell adhesion, shear stress was applied by a flow of 5 L/min over 24 hours. Compared with untreated glutaraldehyde-fixed samples, treatment with the different agents reduced free aldehyde groups gradually (citric acid 5% < citric acid 10% < titanium < aldehyde dehydrogenase). A combination of citric acid 10%, aldehyde dehydrogenase, and titanium coating resulted in a reduction of free aldehyde ligands to 17.3±4.6% (
P
≤0.05) and demonstrated a vitality of seeded cells of 94±6.7% (
P
≤0.05). This procedure yielded a completely confluent layer of regular human endothelial cells (n=5). After application of shear stress for 24 hours on these endothelial layers, cell vitality was 81%.

Conclusions—

Titanium coating combined with chemical procedures yielded significant detoxification and complete endothelialization of conventional glutaraldehyde-fixed pericardium. This new technique might improve glutardialdehyde-fixed cardiovascular bioimplants for better biocompatibility and longer durability.
The Natriuretic Peptide Uroguanylin Elicits Physiologic Actions Through 2 Distinct Topoisomers
Authors: Moss Nicholas G. , Riguera Dorothy A. , Solinga Robert M. , Kessler Marco M. , Zimmer Daniel P. , Arendshorst William J. , Currie Mark G. , Goy Michael F.
Published: March 2009

The peptide uroguanylin regulates electrolyte transport in the intestine and kidney. Human uroguanylin has 2 conformations that can be stably isolated because of their slow interconversion rate. The A isomer potently activates the guanylate cyclase C receptor found primarily in the intestine. The B isomer, by contrast, is a very weak agonist of this receptor, leading to a widely held assumption that it is physiologically irrelevant. We show here, however, that human uroguanylin B has potent natriuretic activity in the kidney. Interestingly, uroguanylin A and B both induce saluretic responses, but the activity profiles for the 2 peptides differ markedly. The uroguanylin B dose-response curve is sigmoidal with a threshold dose of ≈10 nmol/kg of body weight, whereas uroguanylin A has a comparable threshold but a bell-shaped dose-response curve. In addition, our study indicates a unique interplay between the A and B isoforms, such that the A form at high concentrations antagonizes the natriuretic action of the B form. These data show that the kidney contains a uroguanylin receptor of which the pharmacological profile does not match that of the well-defined intestinal uroguanylin receptor (guanylate cyclase C), an observation consistent with previous studies showing that the kidney of the guanylate cyclase C knockout mouse remains responsive to uroguanylin. The results presented here also support the unconventional notion that distinct conformations of a single endocrine peptide can elicit different responses in different tissues.
Maximally Reliable Markov Chains Under Energy Constraints
Authors: Escola Sean , Eisele Michael , Miller Kenneth , Paninski Liam
Published: March 2009

Signal-to-noise ratios in physical systems can be significantly degraded if the outputs of the systems are highly variable. Biological processes for which highly stereotyped signal generations are necessary features appear to have reduced their signal variabilities by employing multiple processing steps. To better understand why this multistep cascade structure might be desirable, we prove that the reliability of a signal generated by a multistate system with no memory (i.e., a Markov chain) is maximal if and only if the system topology is such that the process steps irreversibly through each state, with transition rates chosen such that an equal fraction of the total signal is generated in each state. Furthermore, our result indicates that by increasing the number of states, it is possible to arbitrarily increase the reliability of the system. In a physical system, however, an energy cost is associated with maintaining irreversible transitions, and this cost increases with the number of such transitions (i.e., the number of states). Thus, an infinite-length chain, which would be perfectly reliable, is infeasible. To model the effects of energy demands on the maximally reliable solution, we numerically optimize the topology under two distinct energy functions that penalize either irreversible transitions or incommunicability between states, respectively. In both cases, the solutions are essentially irreversible linear chains, but with upper bounds on the number of states set by the amount of available energy. We therefore conclude that a physical system for which signal reliability is important should employ a linear architecture, with the number of states (and thus the reliability) determined by the intrinsic energy constraints of the system.
Motivation and Engagement Across the Academic Life Span
Authors: Martin Andrew J.
Published: March 2009

From a developmental construct validity perspective, this study examines motivation and engagement across elementary school, high school, and university/college, with particular focus on the Motivation and Engagement Scale (comprising adaptive, impeding/maladaptive, and maladaptive factors). Findings demonstrated developmental construct validity across the three distinct educational stages in terms of goodfitting first- and higher order factors, invariance of factor structure across gender and age, and a pattern of correlations with cognate constructs (e.g., homework completion, academic buoyancy, class participation) consistent with predictions. Notwithstanding the predominantly parallel findings, there was also notable distinctiveness, primarily in terms of mean-level effects, such that elementary school students were generally more motivated and engaged than university/college students who in turn were more motivated and engaged than high school students. Implications for motivation and engagement measurement and theory, research in the psychoeducational domain, and the subsequent potential for performance profiling across the academic life span are discussed.
The MIMIC Method With Scale Purification for Detecting Differential Item Functioning
Authors: Wang Wen-Chung , Shih Ching-Lin , Yang Chih-Chien
Published: March 2009

This study implements a scale purification procedure onto the standard MIMIC method for differential item functioning (DIF) detection and assesses its performance through a series of simulations. It is found that the MIMIC method with scale purification (denoted as M-SP) outperforms the standard MIMIC method (denoted as M-ST) in controlling false-positive rates and yielding higher true-positive rates. Only when the DIF pattern is balanced between groups or when there is a small percentage of DIF items in the test does M-ST perform as appropriately as M-SP. Moreover, both methods yield a higher true-positive rate under the two-parameter logistic model than under the three-parameter model. M-SP is preferable to M-ST, because DIF patterns in real tests are unlikely to be perfectly balanced and the percentages of DIF items may not be small.
Construct Equivalence Across Grades in a Vertical Scale for a K-12 Large-Scale Reading Assessment
Authors: Wang Shudong , Jiao Hong
Published: March 2009

In practice, vertical scales have been continually used to measure students’ achievement progress across several grade levels and have been considered very challenging psychometric procedures. Recently, such practices have been drawing many criticisms. The major criticisms focus on dimensionality and construct equivalence of the latent trait or construct of a vertical scale. Using data from a large-scale reading comprehension assessment program with a vertical scale, this study investigated the dimensionality or the factorial structure for each grade and the equivalence of the factorial structure across grades. The empirical results from this study support the unidimensionality assumption of vertical scale across grades. The results provide empirical evidence regarding construct invariance of vertical scale across wide span of grades.
Demographic, Psychological, and Social Environmental Factors of Loneliness and Satisfaction among Rural-to-Urban Migrants in Shanghai, China
Authors: Ming Wen  , Guixin Wang
Published: March 2009

This study examined factors of loneliness and satisfaction among rural-to-urban migrants in Shanghai, China. Data used in this study were from the Shanghai Rural-to-Urban Migrant Worker Survey conducted by the Institute of Demographic Research, Fudan University. Ordinal logit models were fit to test the hypotheses. A host of demographic, socioeconomic, psychosocial, and neighborhood factors were identified as strong correlates of loneliness and satisfaction among migrants. The effect of experienced discrimination was overwhelmingly negative on migrant mental well-being. Improving migrants' work and living environment, increasing neighborhood amenities, and taking measures to facilitate migrant family members' living together seem to be potentially fruitful ways to promote migrant mental well-being in China.
A Comprehensive Test of General Strain Theory
Authors: Moon Byongook , Morash Merry , McCluskey Cynthia Perez , Hwang Hye-Won
Published: March 2009

Using longitudinal data on South Korean youth, the authors addressed limitations of previous tests of general strain theory (GST), focusing on the relationships among key strains, situational- and trait-based negative emotions, conditioning factors, and delinquency. Eight types of strain previously shown most likely to result in delinquency, including delinquency in the South Korean context, were measured. To better understand how trait- and situational-based negative emotions mediate the connection of strains to delinquency, trait and situational measures were used for anger and depression, emotions commonly expected to promote delinquency. Overall, the findings support GST's key propositions. Most of the eight strains and some interaction terms between strains and conditioning variables had significant effects on various types of delinquency. Furthermore, situational-based negative emotions operated differently than trait-based negative emotions in mediating the relationship between strain and delinquency. These findings raise questions about the assumption that trait-based negative emotions accurately represent situational-based negative emotions in response to strains.
Study of the Anisotropic Nature of the Rupture Properties of a Plain Woven Fabric
Authors: Kovar Radko , Gupta Bhupender S.
Published: March 2009

The ability of a textile fabric to support load at an angle to the two principal directions is important in structures used in load bearing technical applications. Using a simple approach, the angular rupture properties of a plain woven fabric were modeled. The primary restriction imposed was that the fabric width was restrained so that lateral contraction could not occur. This eliminated the possibility of the cut ends of the yarns playing a role and complicating the theoretical treatment. The input parameters were the yarn tensile properties, the fabric warp and weft counts, and the angle to the principal axis at which the properties were determined. A novel test method was developed that conformed to the restriction imposed in the theory and allowed the computed and the measured properties to be compared. Good agreement obtained validates the model and illustrates a new approach to investigating fabric mechanical properties.
Plasma-induced Decolorization of Indigo-dyed Denim Fabrics Related to Mechanical Properties and Fiber Surface Morphology
Authors: Radetić Maja , Jovančić Petar , Puač Nevena , Petrović Zoran Lj. , Šaponjić Zoran
Published: March 2009

The aim of this study was to investigate how morphology of fibers is affected by plasma during the process of decolorization by a low-pressure RF plasma (gas, treatment time, and power were varied) and atmospheric pressure industrial corona (number of passages and power). CIE LAB colorimetric system was used for determination of color difference between untreated and differently plasma-treated denim fabrics. Particular emphasis was put on the morphological changes induced by plasma treatment, because they indicate changes in mechanical properties of the fabrics. The morphology of plasma-treated fibers was analyzed by scanning electron microscopy (SEM). SEM images revealed that, when plasma conditions that lead to a decolorization were chosen, specific fiber surface changes were always observed in the form of submicrometer-sized striations, pits, and cracks. Mechanical properties of denim fabrics were moderately influenced by treatment conditions. The results indicated that decolorization was highly affected by plasma parameters and desired `worn look' effects could be designed by adequate control of plasma processing while paying attention to limiting the plasma-induced damage.
Looking the Other Way
Authors: Knobloch-Westerwick Silvia , Jingbo Meng
Published: March 2009

An experiment with two computer-based sessions (complete data for 156 participants) examined selective exposure to attitude-consistent and counterattitudinal media messages. In the first session, participants indicated interest in politics and news, political attitudes, with four target issues embedded, along with attitude certainty and importance. Attitude accessibility data were derived from response latencies. In the second session, participants browsed an online opinion forum with eight texts about four issues, each with a pair of articles presenting opposing views. Selective exposure was unobtrusively recorded by software and coded as attitude-consistent and counterattitudinal based on individual participants' attitudes. Results show that attitude-consistent exposure dominated regardless of particular issue, with 36% more reading time. Higher habitual news use and attitude certainty both fostered attitude-consistent exposure. Selection of counterattitudinal articles was more likely among participants with greater interest in politics, conservative party preference, stronger party preference, more accessible attitudes, and higher attitude importance.
Independence and interplay between maternal and child risk factors for preschool problem behaviors?
Authors: Hughes Claire , Ensor Rosie
Published: March 2009

This study examined the independence and interplay between cognitive risk factors (poor executive function/emotion understanding) and maternal risk factors (low education/high depression) for preschool problem behaviors, indexed by multi-measure, multi-informant (mother/teacher/ researcher) ratings. A socio-economically diverse sample of 235 children (131 boys, 104 girls; mean age = 4.25 years) completed five executive-function tasks and four emotion-understanding tasks. Controlling for effects of gender, verbal ability and maternal education, individual differences in child problem behavior scores showed significant independent associations with executive dysfunction, emotion understanding and maternal depression. For girls, low maternal education amplified the relationship between executive dysfunction and problem behaviors. In addition, executive dysfunction mediated the relationship between maternal depression and problem behaviors; both executive dysfunction and poor emotion understanding mediated the relationship between low maternal education and problem behaviors. These results demonstrate the cumulative and complex nature of risk for preschool problem behaviors.
Early Francoism and Economic Paralysis in Catalonia, 1939—1951
Authors: Harrison Joseph
Published: March 2009

The entry of General Franco's `liberating' Nationalist army into the city of Barcelona in January 1939 was the prelude to a wave of violent repression across the Principality of Catalonia. In addition to the New State's persecution of the language, culture and national personality of Catalonia, fascist zealots also clamoured for the dismantling of the region's factories and mills. Whilst it was often asserted that the Franco dictatorship systematically discriminated against Catalonia for its treachery in supporting the defeated Second Republic (1931—39), the aim of this article is to present new arguments in defence of the revisionist case that the resulting economic paralysis of Catalonia during the period 1939—51 was not so much the result of the bloody-mindedness of the victors in the Spanish Civil War as the New State's obsession with autarky and interventionism.
Women Entrepreneurs
Authors: Patterson Nicola , Mavin Sharon
Published: March 2009

This article offers a post hoc analysis of the reasons why women leave corporate careers to enter self-employment. Four case studies of women entrepreneurs from North East England are presented.The subjective narratives of these female entrepreneurs highlight the complex nature of their career transition motivations and the issues they confronted while reaching the decision to begin new ventures. It transpired that original motivations for entering self-employment were not fully realized, however, this was compensated for by positive experiences in terms of personal and professional development and a new-found independence and control. Finally, it is suggested that the `Career Transition Motivation Framework' is a useful way of understanding the complexity of women's career transition experiences.
Managing Maternity Fairly and Productively
Authors: Rouse Julia , Sappleton Natalie
Published: March 2009

Multiple policy objectives depend on creating a fair and operational social contract between the small employer, family and state in managing the disruption to paid work (economic production) caused by employee pregnancy and maternity (social reproduction).An Equal Opportunities Commission (EOC) investigation into pregnancy discrimination suggests this social contract is undermined in the UK by ignorance and dispute, causing high rates of non-compliance in small businesses. The EOC recommended that small employers need more support to manage maternity fairly and productively. In this research note we present analysis of the type of support development required.We draw on an audit of existing support and analysis of small employer behaviour and needs to identify failure in existing provision and to present detailed policy recommendations. Further research directions are also identified.