bluuebunny/crossref_metadata_2025 huggingface dataset:
Androgen Signaling in Myocytes Contributes to the Maintenance of Muscle Mass and Fiber Type Regulation But Not to Muscle Strength or Fatigue
Authors: Ophoff Jill , Van Proeyen Karen , Callewaert Filip , De Gendt Karel , De Bock Katrien , Vanden Bosch An , Verhoeven Guido , Hespel Peter , Vanderschueren Dirk
Published: March 2009

Muscle frailty is considered a major cause of disability in the elderly and chronically ill. However, the exact role of androgen receptor (AR) signaling in muscle remains unclear. Therefore, a postmitotic myocyte-specific AR knockout (mARKO) mouse model was created and investigated together with a mouse model with ubiquitous AR deletion. Muscles from mARKO mice displayed a marked reduction in AR protein (60–88%). Interestingly, body weights and lean body mass were lower in mARKO vs. control mice (−8%). The weight of the highly androgen-sensitive musculus levator ani was significantly reduced (−46%), whereas the weights of other peripheral skeletal muscles were not or only slightly reduced. mARKO mice had lower intra-abdominal fat but did not demonstrate a cortical or trabecular bone phenotype, indicating that selective ablation of the AR in myocytes affected male body composition but not skeletal homeostasis. Furthermore, muscle contractile performance in mARKO mice did not differ from their controls. Myocyte-specific AR ablation resulted in a conversion of fast toward slow fibers, without affecting muscle strength or fatigue. Similar results were obtained in ubiquitous AR deletion, showing lower body weight, whereas some but not all muscle weights were reduced. The percent slow fibers was increased, but no changes in muscle strength or fatigue could be detected. Together, our findings show that myocyte AR signaling contributes to the maintenance of muscle mass and fiber type regulation but not to muscle strength or fatigue. The levator ani weight remains the most sensitive and specific marker of AR-mediated anabolic action on muscle.
Muscle-Specific Overexpression of Heparin-Binding Epidermal Growth Factor-Like Growth Factor Increases Peripheral Glucose Disposal and Insulin Sensitivity
Authors: Fukatsu Yasuhide , Noguchi Tetsuya , Hosooka Tetsuya , Ogura Takeshi , Kotani Ko , Abe Takaya , Shibakusa Tetsuro , Inoue Kazuo , Sakai Mashito , Tobimatsu Kazutoshi , Inagaki Kenjiro , Yoshioka Toyo , Matsuo Masahiro , Nakae Jun , Matsuki Yasushi , Hiramatsu Ryuji , Kaku Kohei , Okamura Hitoshi , Fushiki Tohru , Kasuga Masato
Published: March 2009

Physical exercise ameliorates metabolic disorders such as type 2 diabetes mellitus and obesity, but the molecular basis of these effects remains elusive. In the present study, we found that exercise up-regulates heparin-binding epidermal growth factor-like growth factor (HB-EGF) in skeletal muscle. To address the metabolic consequences of such gain of HB-EGF function, we generated mice that overexpress this protein specifically in muscle. The transgenic animals exhibited a higher respiratory quotient than did wild-type mice during indirect calorimetry, indicative of their selective use of carbohydrate rather than fat as an energy substrate. They also showed substantial increases in glucose tolerance, insulin sensitivity, and glucose uptake by skeletal muscle. These changes were accompanied by increased kinase activity of Akt in skeletal muscle and consequent inhibition of Forkhead box O1-dependent expression of the pyruvate dehydrogenase kinase 4 gene. Furthermore, mice with a high level of transgene expression were largely protected from obesity, hepatic steatosis, and insulin resistance, even when maintained on a high-fat diet. Our results suggest that HB-EGF produced by contracting muscle acts as an insulin sensitizer that facilitates peripheral glucose disposal.
Studies in Mice Deficient for the Autoimmune Regulator (Aire) and Transgenic for the Thyrotropin Receptor Reveal a Role for Aire in Tolerance for Thyroid Autoantigens
Authors: Misharin Alexander V. , Nagayama Yuji , Aliesky Holly A. , Rapoport Basil , McLachlan Sandra M.
Published: March 2009

The autoimmune regulator (Aire) mediates central tolerance for many autoantigens, and autoimmunity occurs spontaneously in Aire-deficient humans and mice. Using a mouse model of Graves’ disease, we investigated the role of Aire in tolerance to the TSH receptor (TSHR) in Aire-deficient and wild-type mice (hyperthyroid-susceptible BALB/c background). Mice were immunized three times with TSHR A-subunit expressing adenovirus. The lack of Aire did not influence T-cell responses to TSHR protein or TSHR peptides. However, antibody levels were higher in Aire-deficient than wild-type mice after the second (but not the third) immunization. After the third immunization, hyperthyroidism persisted in a higher proportion of Aire-deficient than wild-type mice. Aire-deficient mice were crossed with transgenic strains expressing high or low-intrathyroidal levels of human TSHR A subunits. In the low-expressor transgenics, Aire deficiency had the same effect on the pattern of the TSHR antibody response to immunization as in nontransgenics, although the amplitude of the response was lower in the transgenics. High-expressor A-subunit transgenics were unresponsive to immunization. We examined intrathymic expression of murine TSHR, thyroglobulin, and thyroid peroxidase (TPO), the latter two being the dominant autoantigens in Hashimoto’s thyroiditis (particularly TPO). Expression of the TSHR and thyroglobulin were reduced in the absence of Aire. Dramatically, thymic expression of TPO was nearly abolished. In contrast, the human A-subunit transgene, lacking a potential Aire-binding motif, was unaffected. Our findings provide insight into how varying intrathymic autoantigen expression may modulate thyroid autoimmunity and suggest that Aire deficiency may contribute more to developing Hashimoto’s thyroiditis than Graves’ disease.
Amphioxus: Beginning of Vertebrate and End of Invertebrate Type GnRH Receptor Lineage
Authors: Tello Javier A. , Sherwood Nancy M.
Published: March 2009

In vertebrates, activation of the GnRH receptor is necessary to initiate the reproductive cascade. However, little is known about the characteristics of GnRH receptors before the vertebrates evolved. Recently genome sequencing was completed for amphioxus, Branchiostoma floridae. To understand the GnRH receptors (GnRHR) from this most basal chordate, which is also classified as an invertebrate, we cloned and characterized four GnRHR cDNAs encoded in the amphioxus genome. We found that incubation of GnRH1 (mammalian GnRH) and GnRH2 (chicken GnRH II) with COS7 cells heterologously expressing the amphioxus GnRHRs caused potent intracellular inositol phosphate turnover in two of the receptors. One of the two receptors displayed a clear preference for GnRH1 over GnRH2, a characteristic not previously seen outside the type I mammalian GnRHRs. Phylogenetic analysis grouped the four receptors into two paralogous pairs, with one pair grouping basally with the vertebrate GnRH receptors and the other grouping with the octopus GnRHR-like sequence and the related receptor for insect adipokinetic hormone. Pharmacological studies showed that octopus GnRH-like peptide and adipokinetic hormone induced potent inositol phosphate turnover in one of these other two amphioxus receptors. These data demonstrate the functional conservation of two distinct types of GnRH receptors at the base of chordates. We propose that one receptor type led to vertebrate GnRHRs, whereas the other type, related to the mollusk GnRHR-like receptor, was lost in the vertebrate lineage. This is the first report to suggest that distinct invertebrate and vertebrate GnRHRs are present simultaneously in a basal chordate, amphioxus.
STAT3 Targets the Regulatory Regions of Gluconeogenic Genes in Vivo
Authors: Ramadoss Preeti , Unger-Smith Nathan E. , Lam Francis S. , Hollenberg Anthony N.
Published: March 2009

The regulation of expression of gluconeogenic genes including glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK) in the liver plays an important role in glucose homeostasis, because aberrant expression of these genes contributes to the development of type 2 diabetes. Previous reports demonstrate that signal transducer and activator of transcription 3 (STAT3) plays a key role in regulating gluconeogenic gene expression, but the mechanism remains unclear. Herein we demonstrate that phosphorylated STAT3 is required for repression of G6Pase expression by IL-6 in both HepG2 cells and mouse liver. Interestingly, PEPCK expression is regulated by STAT3 independent of IL-6 activation. Using in vivo chromatin immunoprecipitation, we demonstrate that STAT3 binds to the promoters of the G6Pase, PEPCK, and suppressor of cytokine signaling (SOCS)3 genes, and its recruitment increases at the G6Pase and SOCS3 promoters with IL-6 treatment. Whereas persistent recruitment of RNA polymerase II is seen on the SOCS3 promoter, consistent with its induction by IL-6, a decrease in polymerase II recruitment and histone H4 acetylation is seen at the G6Pase promoter with IL-6 treatment. Thus STAT3 mediates negative regulation of hepatic gluconeogenic gene expression in vivo by interacting with regulatory regions of these genes.
PLC-γ1 and Rac1 Coregulate EGF-Induced Cytoskeleton Remodeling and Cell Migration
Authors: Li Siwei , Wang Qian , Wang Yi , Chen Xinmei , Wang Zhixiang
Published: March 2009

It is well established that epidermal growth factor (EGF) induces the cytoskeleton reorganization and cell migration through two major signaling cascades: phospholipase C-γ1 (PLC-γ1) and Rho GTPases. However, little is known about the cross talk between PLC-γ1 and Rho GTPases. Here we showed that PLC-γ1 forms a complex with Rac1 in response to EGF. This interaction is direct and mediated by PLC-γ1 Src homology 3 (SH3) domain and Rac1 106PNTP109 motif. This interaction is critical for EGF-induced Rac1 activation in vivo, and PLC-γ1 SH3 domain is actually a potent and specific Rac1 guanine nucleotide exchange factor in vitro. We have also demonstrated that the interaction between PLC-γ1 SH3 domain and Rac1 play a significant role in EGF-induced F-actin formation and cell migration. We conclude that PLC-γ1 and Rac1 coregulate EGF-induced cell cytoskeleton remodeling and cell migration by a direct functional interaction.
Colony stimulating factor 1 is an extrinsic stimulator of mouse spermatogonial stem cell self-renewal
Authors: Oatley Jon M. , Oatley Melissa J. , Avarbock Mary R. , Tobias John W. , Brinster Ralph L.
Published: March 2009

Self-renewal and differentiation of spermatogonial stem cells (SSCs)provide the foundation for testis homeostasis, yet mechanisms that control their functions in mammals are poorly defined. We used microarray transcript profiling to identify specific genes whose expressions are augmented in the SSC-enriched Thy1+ germ cell fraction of mouse pup testes. Comparisons of gene expression in the Thy1+ germ cell fraction with the Thy1-depleted testis cell population identified 202 genes that are expressed 10-fold or higher in Thy1+ cells. This database provided a mining tool to investigate specific characteristics of SSCs and identify novel mechanisms that potentially influence their functions. These analyses revealed that colony stimulating factor 1 receptor (Csf1r) gene expression is enriched in Thy1+ germ cells. Addition of recombinant colony stimulating factor 1 (Csf1), the specific ligand for Csf1r, to culture media significantly enhanced the self-renewal of SSCs in heterogeneous Thy1+ spermatogonial cultures over a 63-day period without affecting total germ cell expansion. In vivo, expression of Csf1 in both pre-pubertal and adult testes was localized to clusters of Leydig cells and select peritubular myoid cells. Collectively, these results identify Csf1 as an extrinsic stimulator of SSC self-renewal and implicate Leydig and myoid cells as contributors of the testicular stem cell niche in mammals.
The sea urchin animal pole domain is a Six3-dependent neurogenic patterning center
Authors: Wei Zheng , Yaguchi Junko , Yaguchi Shunsuke , Angerer Robert C. , Angerer Lynne M.
Published: March 2009

Two major signaling centers have been shown to control patterning of sea urchin embryos. Canonical Wnt signaling in vegetal blastomeres and Nodal signaling in presumptive oral ectoderm are necessary and sufficient to initiate patterning along the primary and secondary axes, respectively. Here we define and characterize a third patterning center, the animal pole domain(APD), which contains neurogenic ectoderm, and can oppose Wnt and Nodal signaling. The regulatory influence of the APD is normally restricted to the animal pole region, but can operate in most cells of the embryo because, in the absence of Wnt and Nodal, the APD expands throughout the embryo. We have identified many constituent APD regulatory genes expressed in the early blastula and have shown that expression of most of them requires Six3 function. Furthermore, Six3 is necessary for the differentiation of diverse cell types in the APD, including the neurogenic animal plate and immediately flanking ectoderm, indicating that it functions at or near the top of several APD gene regulatory networks. Remarkably, it is also sufficient to respecify the fates of cells in the rest of the embryo, generating an embryo consisting of a greatly expanded, but correctly patterned, APD. A fraction of the large group of Six3-dependent regulatory proteins are orthologous to those expressed in the vertebrate forebrain, suggesting that they controlled formation of the early neurogenic domain in the common deuterostome ancestor of echinoderms and vertebrates.
Experimental and numerical analysis of the roller-bench endurance test on a motorscooter
Authors: Frendo F , Rosellini W
Published: March 2009

This paper describes an activity aimed at analysing the loads occurring on a two-wheeler during one of the most widespread tests among two-wheeler companies. In this test, the vehicle with additional ballasts, is positioned on two rollers, having synchronized rotational speed, and is subjected to loads coming from obstacles positioned on the rollers' surface. In order to achieve an in-depth understanding of the loads produced by the test, a vehicle was provided with displacement transducers, accelerometers, and strain gauges. At the same time, two multi-body models of the test were set up, in which the motorscooter had a rigid frame or a flexible frame respectively. The dynamics of the tyre was reproduced by the rigid ring model, where the tyre interacts with the wheel rim by means of linear and rotational springs and dampers. The loads from the obstacles are evaluated on the basis of a series of experimental curves (envelope properties of the tyre) directly obtained with the tyres and obstacle employed for the tests.

The comparison between experimental and numerical results regarding suspension strokes, wheel vertical accelerations, and vertical and longitudinal loads showed fairly good agreement; it is also shown how the model having the rigid frame overestimates the peaks in the vertical load.

The availability of an accurate model for this kind of test in the early phase of the development process of new vehicles, allows the design of structural components to be optimized.
A messy genetic algorithm and its application to an approximate optimization of an occupant safety system
Authors: Lee J , Kim T
Published: March 2009

The paper explores an adaptation of a messy genetic algorithm (mGA) and back-propagation neural network (BPN) in the context of a global approximate optimization of an occupant safety system in automotive design. The design objective is to determine the airbag vent hole size, seatbelt load limiter, steering column collapse load, and airbag tether length by minimizing both the head injury criterion (HIC) and thorax injury criterion (centre-of-gravity criterion (CGC)) for passenger protection. The analysis of the occupant safety system is highly non-linear, thus an mGA is adopted as a global optimizer in the present study. For global function approximations, BPN models are established to represent output responses of the HIC and CGC. A design of experiments is conducted to examine the interaction effect between the design variables and to generate training data for use in the BPN. The paper develops new schemes of adaptive random seed selection and adaptive operation probability to enhance the mGA performance. A number of benchmarking problems are first explored to support proposed mGA strategies, and approximate optimization is performed for the design of occupant safety system.
Improved combustion submodels for modelling gasoline engines with the level set G equation and detailed chemical kinetics
Authors: Yang S , Reitz R D
Published: March 2009

Five combustion submodels have been improved for modelling gasoline engines with the level set G equation and detailed chemical kinetics. These combustion submodels include a transport equation residual model, the introduction of a Damkohler criterion model for assessing the combustion regime of flame-containing cells, the precise calculation of ‘primary heat release’ based on the subgrid scale unburned or burned volumes of flame-containing cells, the modelling of flame front quenching in highly stratified mixtures, and a recently developed primary reference fuel (PRF) mechanism. In the transport equation residual model a fictitious species concept is introduced to account for the residual gases in the cylinder, which have a great effect on the laminar flame speed. The residual gases include carbon dioxide (CO2), water (H2O), and nitrogen (N2) remaining from the previous engine cycle or introduced using exhaust gas recirculation (EGR). This pseudo-species is described by a transport equation. The transport equation residual model differentiates between CO2 and H2O from the previous engine cycle or EGR and that which is from the combustion products of the current engine cycle. The Damkohler criterion model is based on a comparison between a laminar flame propagation timescale and the chemical kinetics timescale to determine whether the level set G-equation model or chemical kinetics should be used for assessing the combustion processes in flame-containing cells. The results from implementation of the Damkohler model range between the G-equation model and pure chemistry, depending on the conditions. The improved primary-heat-release calculation model precisely considers the chemical kinetics heat release in unburned regions of flame-containing cells and thus is thought to be physically reasonable. The simulation results show that the flame-front-quenching model effectively captures the flame quench phenomenon in highly stratified mixtures which are typical in gasoline direct-injection engines. Validation of the new PRF mechanism shows that the calculated ignition delay matches shock tube data very well over a wide range of conditions. The integrated model was used to simulate the combustion process in a gasoline turbocharged direct-injection engine, and the same set of combustion model parameters for both high loads and low loads were used. For both high-load and low-load operating conditions, good agreement with the experimental in-cylinder pressure, heat release rates, and mass fraction burned data was obtained.
Motorcycle-to-car and scooter-to-car collisions: speed estimation from permanent deformation
Authors: Wood D P , Glynn C , Walsh D
Published: March 2009

This paper proposes from fundamental mechanics that the specific energy ( E/ M) absorption characteristics of motorcycles and scooters in frontal impacts are similar where the primary load path is through the front wheel and fork assembly. Examination of 43 barrier test results for 14 different model types of motorcycle and scooter over the impact speed range from 10km/h to 76km/h shows that the specific energy versus wheelbase shortening characteristics are similar and that a single specific collision energy ( E/ M) regression equation with its associated statistical distribution ( r2=0.845) can be used to represent the motorcycle and scooter populations in frontal impact for wheelbase shortening up to 0.45m where the front-fork and front-wheel assemblies remain intact, albeit deformed. Data from 31 staged tests where motorcycles or scooters impacted stationary cars at 90° are used to obtain the energy absorption characteristics of the sides of cars subject to frontal motorcycle or scooter impact. These two regressions are used to estimate collision energy Eca from the permanent deformation or penetration depth of the collision partners, which, when substituted into the standard impact energy loss equation with the appropriate collision partner masses, yields an estimation of collision speed Vccs. This procedure for calculating collision closing speed Vccs is validated against 13 staged tests (six 90° impacts against stationary cars and seven angled impacts at angles up to 45° from the normal, four of which were against moving cars) and shows that the predicted Vccs speeds bound the actual speeds with a standard deviation of 11.2km/h for collision closing speeds up to 122km/h.
Experimental investigation of the effect of a B70 biodiesel blend on a common-rail passenger car diesel engine
Authors: Tziourtzioumis D , Demetriades L , Zogou O , Stamatelos A M
Published: March 2009

The results of engine bench tests of a 2.0l common-rail high-pressure injection passenger car diesel engine fuelled by B70 biodiesel blend are compared with the corresponding results of baseline tests with standard EN 590 diesel fuel. Engine performance and carbon monoxide (CO), total hydrocarbon (THC), and nitrogen oxide (NO x) emissions were measured. Also, indicative particulate sampling was made with a simplified undiluted exhaust sampler. The aim of this study was to understand better how the engine's electronic control unit (ECU) responds to the different fuel qualities. A series of characteristic operation points for engine testing is selected to serve this purpose better. Data acquisition of the engine ECU variables was made through INCA software. Also, additional data acquisition based on external sensors was carried out by means of Labview software. The results enhance understanding of the engine ECU behaviour with the B70 biodiesel blend. Also, they are compared with what is known from the related literature for the behaviour of common-rail diesel engines with biodiesel blends.
Retrofitting CO2 capture ready fossil plants with post-combustion capture. Part 2: Requirements for natural gas combined cycle plants using solvent-based flue gas scrubbing
Authors: Lucquiaud M , Patel P , Chalmers H , Gibbins J
Published: March 2009

A number of natural gas combined cycle (NGCC) power stations recently permitted in the UK have been required to be CO2 capture ready so that carbon capture and storage can be retrofitted once it is commercially viable (or legally required). Several options for future CO2 capture from NGCC units can be envisaged including post-combustion capture technology using flue gas scrubbing with aqueous solvents. When an NGCC plant is designed to be ready for a retrofit with post-combustion capture, one of the most important technical considerations is the steam extraction pressure and flow to provide the energy necessary for solvent regeneration. This is determined by the choice of solvent used, but new solvents are being developed and the exact future requirements, in perhaps 10–20 years time, cannot be predicted. Ways in which designs for the steam cycle of NGCC plants can cope with this challenge are presented. Several alternatives to mitigate the loss of power output of NGCC plants retrofitted with post-combustion capture and to achieve improved plant flexibility are also assessed and compared.
Metagenomic Pyrosequencing and Microbial Identification
Authors: Petrosino Joseph F , Highlander Sarah , Luna Ruth Ann , Gibbs Richard A , Versalovic James
Published: March 2009

Background: The Human Microbiome Project has ushered in a new era for human metagenomics and high-throughput next-generation sequencing strategies.

Content: This review describes evolving strategies in metagenomics, with a special emphasis on the core technology of DNA pyrosequencing. The challenges of microbial identification in the context of microbial populations are discussed. The development of next-generation pyrosequencing strategies and the technical hurdles confronting these methodologies are addressed. Bioinformatics-related topics include taxonomic systems, sequence databases, sequence-alignment tools, and classifiers. DNA sequencing based on 16S rRNA genes or entire genomes is summarized with respect to potential pyrosequencing applications.

Summary: Both the approach of 16S rDNA amplicon sequencing and the whole-genome sequencing approach may be useful for human metagenomics, and numerous bioinformatics tools are being deployed to tackle such vast amounts of microbiological sequence diversity. Metagenomics, or genetic studies of microbial communities, may ultimately contribute to a more comprehensive understanding of human health, disease susceptibilities, and the pathophysiology of infectious and immune-mediated diseases.
Penetration Rate Effect on Miniature Cone Tip Resistance for Different Cohesionless Materials
Authors: Kumar Jyant , Raju K. V. S. B.
Published: March 2009

Cone penetrometer tests were carried out in a 140 mm diameter triaxial chamber by using a miniature cone of diameter 19.5 mm. The rate of cone penetration was varied from 0.01 mm/s to 0.1 mm/s. Tests were performed in (i) clean sand, (ii) silty sand, and (iii) sand added with fly ash. Two different effective vertical pressures (σv), 100 kPa and 300 kPa, were employed. It was noted that for clean and silty sand, the effect of penetration rate on the ultimate tip resistance (qcu) of the cone was found to remain only marginal. On the other hand, for sand added with 30 % fly ash, the variation in qcu values with penetration rate was found to become quite significant. The effect of penetration rate on qcu in all the cases was found to increase with a decrease in the rate of cone penetration. It was noted that with an increase in σv, the effect of penetration rate on qcu was found to become smaller. The effect of the cone penetration rate on qcu generally reduces with an increase in the relative density of the material.
Severity of Quenching and Kinetics of Wetting of Nanofluids and Vegetable Oils
Authors: Jagannath Vaishali , Prabhu K. Narayan
Published: March 2009

In the present work, the suitability of vegetable oil blends with mineral oil and alumina based nanofluids as quench media for industrial heat treatment was investigated. Sunflower oil, palm oil, and mineral oil were used for preparing the blends. Alumina based nanofluids of varying concentrations ranging from 0.01–4 % were used. The size of alumina particles was about 50 nm. The severity of quenching and heat transfer coefficients were estimated during quenching of copper probes. Heat transfer coefficients were estimated using a lumped heat capacitance model. The static contact angle was measured on copper substrates having a surface texture similar to the probes used for estimation of heat transfer coefficients. A dynamic contact angle analyzer was used for this purpose. The measured contact angles of nanofluids on copper were high compared to oils, indicating poor wetting by quench media that are polar in nature. Wetting characteristics had a significant effect on heat transfer coefficients estimated during quenching.
Explanation on the Origin of Distortion in Induction Hardened Ring Specimens by Computer Simulation
Authors: Horino T. , Ikuta F. , Arimoto K. , Jin C. , Tamura S.
Published: March 2009

Explanation of the distortion mechanism is important for realizing the low-distortion and distortion-adapted induction hardening processes. Two of our authors applied computer simulation to examine distortions of ring specimens induction hardened on their outer side and also tempered. Simulated deformations agreed well with the experimental results. In this study, a simulation for the same experiment was carried out by the more enhanced modeling techniques. The possibility of explaining the origin of distortion in induction hardened ring specimens was shown clearly from simulated distribution changes of temperature, metallic structures, stresses, and strains.
Impact Attenuation Characteristics of Thin Walled Collapsible Air Chambers for Use in Protective Helmets
Authors: Hoshizaki T. B. , Post A.
Published: March 2009

For the past 40 years, helmets have primarily used expanded polystyrene, vinyl nitrile, and expanded polypropylene foams for impact attenuation. Even though the packaging industry has investigated a variety of structures for impact management, the helmet industry has been slow to adopt these types of innovations. More recently, engineered structures have been developed and introduced for use in the helmet industry. This study was intended to describe the impact characteristics of a thin walled collapsible air chambers designed to be used in sport helmets. This study investigated three structures: rigid walls, a chamber with rigid walls and a vent, and a chamber with rigid walls and no vent. Each structure was impacted with a 5 kg weight at three velocities: 1.9, 2.8, and 3.4 m/s. The three structures were also made using two materials of different stiffnesses. Analysis of the results revealed that the effect of the walls, vent, and material stiffness interacted to produce effective energy management. The results demonstrated that by changing the material stiffness, wall thickness, and vent diameter the performance of the chambers can be engineered to effectively manage different levels of energy.
Psychopathologic and cognitive investigations in schizophrenia
Authors: Farkas Márta
Published: March 2009

A dolgozat témája egyfelől két pszichopatológiai tünet elemzése egy hosszú távú utánkövetéses vizsgálat – „Budapest 2000” – keretében elsősorban szkizofréniában szenvedő nőbetegek körében; másfelől a genetikai prediszpozícióhoz közelinek tartott kognitív endofenotipikus vonás – az asszociatív tanulás és tanult ekvivalencia – vizsgálata szkizofrén betegek és hozzájuk illesztett egészséges kontrollok csoportjaiban.
Célkitűzés:
I. Megvizsgálni 1. a téveszme és a hallucináció súlyosságát, annak időbeli változását, előfordulásának valószínűségét az egyes klinikai csoportokban; 2. a klinikai csoportokra jellemző kórlefolyást a két tünet alapján. II. Tanulmányozni az asszociációs tanulás és a tanult ekvivalencia jelenségét abban az összefüggésben, hogy ezek a képességek elkülönítik-e a szkizofrén betegeket az egészséges kontrollcsoporttól, illetve a szkizofrénián belül elkülönülnek-e a deficit- és nem deficitszkizofrénia-alcsoportok.
Módszerek:
Az első, klinikai tüneteket elemző vizsgálatban 221 nőbeteg vett részt, a tüneteket a Rockland–Pollin-féle becslésskála, valamint a Sajátos tünetek listája segítségével értékeltük a betegség heveny szakában (indexidőpont), valamint 5 évvel és 21–33 évvel az indexidőpontot követően. Diagnosztikus besorolásuk eredetileg Leonhard rendszere szerint történt, de elvégeztük a DSM-IV szerinti diagnosztizálásukat is. A második vizsgálat keretében 49 szkizofrén férfi és nőbeteget, valamint 20 illesztett egészséges kontrollt vizsgáltunk meg a Rutgers-féle tanultekvivalencia-teszt, valamint három, döntően frontális neuropszichológiai teszt segítségével. Az utóbbi vizsgálat keretében a klinikai tüneteket a Positive and negative symptom scale-lel mértük.
Eredmények:
A pozitív dimenzió tüneteinek változásában a hosszú távú lefolyás során különbség mutatkozik: hallucináció súlyosságában az 5 éves vizsgálat utáni időszakban szignifikáns romlás van, míg a téveszme mérséklődik, de ez a javulás nem szignifikáns. A két tünet, valamint a szociális funkcionálás tekintetében elkülönül egymástól az affektív, cikloid és szkizofrén betegek csoportja az utánkövetés időszaka alatt, és a két tünet jellemzői szerint a paranoid, hebefrén és katatón alcsoportok is. A mediális temporalis lebeny működésével kapcsolatos tanultekvivalencia-vizsgálatban a szkizofrén betegek rosszabbul teljesítettek, mint az egészséges kontrollcsoport. Az agytörzsi magvak mediálta asszociatív tanulásban nyújtott teljesítményük elkülönítette a deficit- vs. nem deficitszkizofrén alcsoportot.
Következtetések:
1. A kognitív dimenzió elkülöníti a szkizofrénia deficit- és nem deficitalcsoportjait. 2. A pozitív dimenzió tünetei alapján a szkizofrénia klasszikus típusai válnak szét.
Effectiveness of new, once-daily 5-aminosalicylic acid in the treatment of ulcerative colitis
Authors: Lakatos Péter László , Lakatos László
Published: March 2009

Az 5-aminoszalicilsav- (5-ASA-) készítmények mind a mai napig a colitis ulcerosa terápiájának alapvető gyógyszereit jelentik. Számos orálisan adható 5-ASA-készítmény van forgalomban, beleértve az azo-kötést tartalmazó prodrugokat (például sulfalazin, olsalazin, balzalazid), valamint a mesalazin elnyújtott és kontrollált hatóanyag-kibocsátású kiszereléseit. Az orális terápia hatékonysága a beteg jó együttműködésén is múlik, amelynek gátat szabhat a naponta többször adott, nagyszámú tabletta bevétele. Ez a tényező a colitis ulcerosában szenvedő betegek terápiájának pontos betartásában jelentős akadályt képezhet. A közelmúltban egy új, naponta egyszer adandó, egyedülálló multimátrix mesalazinkészítmény és a szintén naponta egy alkalommal adható mesalazingranulátum hatékonynak bizonyult az enyhe-közepes súlyosságú colitis ulcerosa indukciós és fenntartó terápiájában. A mellékhatásprofil ugyanakkor nem különbözött a hagyományos mesalazinkészítményektől. A ritka adagolás a betegek jobb hosszú távú compliance-e által hozzájárulhat a betegek hatékonyabb kezeléséhez és várhatóan a colitis ulcerosával kapcsolatos colorectalis carcinoma rizikójának csökkentéséhez. A szerzők az alábbi közleményben összefoglalják az új, naponta egyszer adandó mesalazinkészítmények rövid és közepes távú hatékonyságával és biztonságosságával kapcsolatban elérhető irodalmi adatokat.
Molecular epidemiology of hepatitis E virus in Hungary: endemic, food-borne zoonosis
Authors: Reuter Gábor , Fodor Domonka , Forgách Petra , Kátai Andrea , Szűcs György
Published: March 2009

A hepatitis E-vírus (HEV) az egyik leggyakoribb, széklettel terjedő, hepatitist okozó ágens a fejlődő országokban. A fejlett országokban a vírus szórványos emberi megbetegedésekből és házisertésekből való kimutatása azonban felveti a HEV zoonosis útján való terjedését is.
Célkitűzés:
A hepatitis E-vírus kimutatása emberben, házi- (sertés, szarvasmarha) és vadon élő (vaddisznó, őz) állatokban, és a vírus molekuláris epidemiológiája hazánkban.
Módszer:
A szerzők a 2001 és 2006 között a szegedi városi kórház infektológiai osztályán ismeretlen eredetű hepatitisben szenvedő betegek szérummintáit HEV ELISA módszerekkel előszűrték, majd a HEV-IgM-pozitív szérummintákat és az állati bélsár-, máj-, valamint bélmintákat RT-PCR módszerekkel vizsgálták.
Eredmények:
Összesen 116 (9,6%) beteg szérummintája tartalmazott HEV-IgM ellenanyagot. Ötvenhárom HEV-IgM-pozitív szérummintából 13-ban (24,5%) a HEV is kimutatható volt RT-PCR és szekvenálási módszerekkel. A sertésmintákból 42 minta (bélsár: 22,7%, máj: 30,8%), az őzmintákból 11 (máj: 34,4%) és a vaddisznómintákból 9 minta (máj: 12,2%) mutatott RT-PCR-pozitivitást. Egy Indiából importált 1-es genotípusú HEV víruson kívül minden további HEV (12 humán, 19 sertés, 3 őz, 2 vaddisznó) a 3-as genotípusba tartozik. Genetikailag megegyező szekvenciájú HEV-et lehetett kimutatni őzből és egy emberi fertőzésből, továbbá két-két emberi fertőzésből.
Megbeszélés:
A HEV endémiásan jelen lévő kórokozó. A nyers vagy nem kellően hőkezelt hústermékek (házi és vadhús) elfogyasztása a legvalószínűbb forrása a hazai szórványos hepatitis E-fertőzéseknek. A 3-as genotípusú HEV-ek okozta endémiás humán fertőzések fajokon keresztüli zoonosisok, amelyek élelmiszerek közvetítésével terjednek hazánkban.
Reproductive Strategies of Sea Basses based on Larval Abundance in Magdalena Bay, Mexico, 1982–1986
Authors: Avendaño-Ibarra Raymundo , Hernández-Rivas Martín E. , Silva-Dávila Roxana
Published: March 2009

We analyzed the reproductive strategies of four sea basses Paralabrax spp. based on larval abundance and sea surface temperature during a period affected by the El Niño of 1982–1983. Zooplankton samples were taken monthly in the Magdalena–Almejas lagoon complex of Baja California Sur, Mexico, from January 1982 to November 1986. Larvae of four sea bass species were recorded; those of the spotted sand bass P. maculatofasciatus were dominant, contributing 43% of total abundance. Barred sand bass P. nebulifer constituted 28% of the sampled larvae, goldspotted sand bass P. auroguttatus contributed 26%, and kelp bass P. clathratus made up 3%. During 1983–1984, the larval abundances of spotted sand bass and goldspotted sand bass decreased (by >50% and 90%, respectively), while the abundance of barred sand bass increased by nearly 25%. A seasonal larval abundance maximum for all species was recorded in summer and autumn, but a differential reproductive pattern inferred from larval abundance was determined. Spotted sand bass showed continuous reproductive activity with peaks in February, June, August–September, and November. Barred sand bass larval abundance indicated one reproductive period with peaks in June and November; a single reproductive period (August) was found for goldspotted sand bass. The abundance of kelp bass larvae was very low, and we were not able to identify a reproductive pattern. Spawning habitat occurred at the relatively narrow temperature range of 19–24°C for spotted sand bass and at 24–28°C for barred sand bass; the widest range was recorded for goldspotted sand bass (22–29°C). The temporal segregation and the differences in spawning habitat permitted the identification of three different reproductive strategies in which there exists a certain degree of overlap. This study represents a first step in understanding the reproductive cycle of three species of sea basses in Magdalena Bay.
Age, Growth, and Age Structure of Amarillo Snapper off the Coast of Mazatlán, Sinaloa, Mexico
Authors: García-Contreras Oscar Enrique , Quiñónez-Velázquez Casimiro , Morán-Angulo Ramón Enrique , Valdez-Pineda Maria Candelaria
Published: March 2009

To estimate age, describe individual growth, and determine the catch age structure of amarillo snapper Lutjanus argentiventris off the coast of Mazatlán, Sinaloa, artisanal fishery catches were sampled from December 2002 to November 2003. A total of 483 specimens were sampled that measured between 160 and 660 mm total length (TL) and had a total weight (TW) of between 60 and 4,685 g. The TL–TW relationship (TW = 0.0135TL3.03) showed isometric growth (slope b = 3.0; t-test: P > 0.05). From growth mark readings in 265 sagittal otoliths, 12 age-groups between ages 1 and 17 were identified, and the predominant ages were 1–3 years. Monthly change in the otolith edge width allowed us to determine that growth marks had an annual periodicity; the formation of each growth mark ended in June, which coincided with the species' main spawning peak. Von Bertalanffy growth equation parameters estimated from age–TL data were 735 mm for asymptotic length (L∞), 0.097 per year for the growth coefficient (K), and −2.05 years for age at a TL of zero (t0). The age composition of the catch indicated that 95% of specimens were between ages 1 and 5 and 80% of specimens were younger than age 4 (the age at which 50% of the population reproduces for the first time). Age-6 amarillo snapper had a reduced importance, not exceeding 5%. This study is the first that uses otoliths for determining age and describing growth of the amarillo snapper.
Fishers' Reasons for Poaching Abalone (Haliotidae): A Study in the Baja California Peninsula, Mexico
Authors: Reyes Ricardo Bórquez , Pombo Oscar Alberto , Díaz Germán Ponce
Published: March 2009

Although Mexico has a well-established legal framework regulating fisheries for the green abalone Haliotis fulgens and pink abalone H. corrugata, there is empirical evidence about a sizeable abalone black market and substantial sectors of fishing communities dedicated to poaching. An investigation was conducted about abalone poaching in a bay located off the Baja California Peninsula, Mexico. The main objective was to determine how poaching is perceived by abalone fishermen, particularly the attitudes of legal and illegal fishing groups and the factors that determine their perception of poaching. Abalone fishermen's perceptions and attitudes about poaching seem to be conditioned by a small number of factors that were identified through a discriminant analysis (e.g., deep-seated practices and knowledge about abalone fisheries; between-group violence; and the likelihood that a given poaching work day will fail due to capture by authorities, confrontation by legal fishermen, or insufficient abalone harvest). This investigation provides an indirect exploration of the abalone poaching phenomenon and the factors underlying this practice.
Growth and Fisheries of the Black Ark Anadara tuberculosa, a Bivalve Mollusk, in Bahía Magdalena, Baja California Sur, Mexico
Authors: Félix-Pico Esteban F. , Ramírez-Rodríguez Mauricio , Holguín-Quiñones Oscar
Published: March 2009

To determine trends in landings and growth of the pustulose ark or black ark Anadara tuberculosa, a bivalve mollusk in the Bahía Magdalena–Bahía Almejas region along the southwestern coast of the Baja California Peninsula, Mexico, catch statistics recorded by artisan or small-scale fishermen from 1992 to 2002 and size frequency distributions of samples from commercial catches (November 1998–December 2000) were analyzed. Catch data revealed considerable fluctuations and a trend toward decline. No defined seasonal exploitation pattern was observed; however, on average, the months with the highest catches coincided with the highest reproductive activity. There was evidence of a decrease in black ark density, which might be accounted for by the fishery. Parameters derived from the von Bertalanffy growth equation confirm that individuals reach the minimum catch size of 60 mm in a little more than 1 year. Catch sizes ranged between 40 and 80 mm.
Use of GIS to Prioritize Cogongrass (Imperata cylindrica) Control on Camp Shelby Joint Forces Training Center, Mississippi
Authors: Yager Lisa Y. , Smith Matt
Published: March 2009

Geographic information systems (GIS) analysis considering size and spatial distribution of infestations of invasive species on a landbase can assist with developing appropriate control strategies for that species. We used GIS to evaluate strategies that placed highest priority on: smallest patches of cogongrass, largest patches of cogongrass, and cogongrass patches on land considered high-value under military training and conservation priorities on Camp Shelby Joint Forces Training Center (CSJFTC), MS. Strategies were first evaluated using predicted increase in area of new growth prevented, if prioritized patches were treated with herbicide. Travel and other time needed to implement strategies were then assessed as they affected total area treated. Assuming equivalent areas treated, predicted total reduction in area was consistently highest for the strategy prioritizing smallest patches and lowest for the strategy prioritizing largest patches. However, travel and other time was sufficiently reduced for the strategy prioritizing patches on high-value land compared to the other strategies to suggest that this strategy would result in the greatest reduction in area infested with cogongrass. Analyses of spatial distribution and size of infestations can assist land managers with selecting the appropriate strategy for controlling invasive species.
Response of Broom Snakeweed (Gutierrezia sarothrae) and Cool-Season Grasses to Defoliation
Authors: Ralphs Michael H.
Published: March 2009

Broom snakeweed is one of the most widespread range weeds in western North America. Although a native plant, it increases with disturbance such as overgrazing, fire, and drought, and can dominate sites. The objective of this study was to test the hypothesis that defoliation of broom snakeweed alone, and along with associated grasses, would reduce its vigor and increase its mortality in bunchgrass plant communities. The study was conducted at two locations: near Nephi, UT in an invaded crested wheatgrass stand and at Howell, UT in a bluebunch wheatgrass/Wyoming big sagebrush community. Clipping treatments consisted of (1) untreated Control; (2) All Clip—clipping all herbaceous vegetation 2 cm above the soil surface, and current season foliar growth of snakeweed; (3) Grass Clip—clipping all grass and forb plants; (4) Snakeweed Clip—clipping current season foliar growth. Treatments were randomly assigned to 1-m2plots and clipped in May or late August. Plots were measured and clipped at the respective seasons annually from 2004 to 2007. Defoliation of snakeweed in spring in the Snakeweed Clip treatment caused higher mortality and lower size and vigor of remaining plants than the other treatments at the end of the study. Clipping all vegetation also reduced snakeweed density at Nephi, but not at Howell. There was little regrowth of bluebunch wheatgrass at Howell in the All Clip treatment; thus, it was likely to have not competed with snakeweed regrowth for limited soil moisture. Bluebunch wheatgrass cover declined at Howell in the All and Grass Clip treatments. Crested wheatgrass was not adversely affected by spring defoliation in the All and Grass Clip treatments, and it increased in the Snakeweed Clip treatment. There were few differences in the fall defoliations. Spring defoliation of snakeweed put it at a competitive disadvantage with both intact perennial bunchgrasses and regrowth crested wheatgrass, thus enhancing its mortality.
Amur Honeysuckle (Lonicera maackii) Management Method Impacts Restoration of Understory Plants in the Presence of White-Tailed Deer (Odocoileus virginiana)
Authors: Cipollini Kendra , Ames Elizabeth , Cipollini Don
Published: March 2009

Management methods for invasive species vary in their restoration success in the presence or absence of herbivores. We investigated the performance of understory plants after management of the invasive shrub Amur honeysuckle using two herbicide-based methods (cut/paint and basal application) in fenced and unfenced plots. The cut/paint method resulted in the removal of above-ground stems, while the basal application method resulted in the dead stems remaining in place. Light level in the cut/paint treatment was higher than in the basal application treatment, which was higher than in the control (no management) treatment. Across fencing treatments, fruit production, height, and subsequent recruitment of transplanted jewelweed were greater in the cut/paint treatment. Across management treatments, jewelweed plants were taller in the fenced treatment. Native species richness was generally higher in the cut/paint and basal application treatments than in the control treatment. There were more jewelweed recruits, more jewelweed fruits, and greater native species richness in the cut/paint treatment than in the basal application treatment in fenced plots, but these measures were similar in both management treatments in unfenced plots. Thus standing dead stems of Amur honeysuckle offered protection from damage in the presence of herbivores, offsetting the advantage of the cut/paint method seen in the fenced plots. There was a trend for more leaves of transplanted wild ginger in the basal application treatment. There were more invasive garlic mustard and more Amur honeysuckle seedlings in the cut/paint treatment than in the control treatment. Our results illustrate the complexities involved in selecting appropriate restoration management techniques given herbivore pressure, differential species response, and presence of multiple invasive species. In our study, we demonstrated that the basal application honeysuckle management method (and therefore perhaps similar methods that leave the dead stems standing) led to increased understory plant restoration success when compared to the cut/paint method.