bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of Staphylococcus aureus: DNase and Mannitol salt agar improve the efficiency of the tube coagulase test
Authors: Kateete David P , Kimani Cyrus N , Katabazi Fred A , Okeng Alfred , Okee Moses S , Nanteza Ann , Joloba Moses L , Najjuka Florence C 
Published: August 2010

AbstractBackgroundThe ideal identification ofStaphylococcus aureusclinical isolates requires a battery of tests and this is costly in resource limited settings. In many developing countries, the tube coagulase test is usually confirmatory forS. aureusand is routinely done using either human or sheep plasma. This study evaluated Mannitol salt agar and the deoxyribonuclease (DNase) test for improving the efficiency of the tube coagulase test in resource limited settings. The efficiency of human and sheep plasma with tube coagulase tests was also evaluated.MethodsOne hundred and eighty Gram positive, Catalase positive cocci occurring in pairs, short chains or clusters were subjected to growth on Mannitol salt agar, deoxyribonuclease and tube coagulase tests. Of these, isolates that were positive for at least two of the three tests (n = 60) were used to evaluate the performance of the tube coagulase test for identification ofS. aureus, using PCR-amplification of thenucgene as a gold standard.ResultsHuman plasma was more sensitive than sheep plasma for the tube coagulase test (sensitivity of 91% vs. 81% respectively), but both plasmas had very low specificity (11% and 7% respectively). The sensitivity and specificity of the tube coagulase test (human plasma) was markedly improved when Mannitol salt agar and DNase were introduced as a tri-combination test for routine identification ofStaphylococcus aureus(100% specificity and 75% sensitivity). The specificity and sensitivity of Mannitol salt agar/DNase/tube coagulase (sheep plasma) combination was 100% and 67%, respectively.ConclusionThe efficiency of the tube coagulase test can be markedly improved by sequel testing of the isolates with Mannitol salt agar, DNase and Tube coagulase. There is no single phenotypic test (including tube coagulase) that can guarantee reliable results in the identification ofStaphylococcus aureus.
Entraining in trout: a behavioural and hydrodynamic analysis
Authors: Przybilla Anja , Kunze Sebastian , Rudert Alexander , Bleckmann Horst , Brücker Christoph 
Published: August 2010

SUMMARYRheophilic fish commonly experience unsteady flows and hydrodynamic perturbations. Instead of avoiding turbulent zones though, rheophilic fish often seek out these zones for station holding. A behaviour associated with station holding in running water is called entraining. We investigated the entraining behaviour of rainbow trout swimming in the wake of a D-shaped cylinder or sideways of a semi-infinite flat plate displaying a rounded leading edge. Entraining trout moved into specific positions close to and sideways of the submerged objects, where they often maintained their position without corrective body and/or fin motions. To identify the hydrodynamic mechanism of entraining, the flow characteristics around an artificial trout placed at the position preferred by entraining trout were analysed. Numerical simulations of the 3-D unsteady flow field were performed to obtain the unsteady pressure forces. Our results suggest that entraining trout minimise their energy expenditure during station holding by tilting their body into the mean flow direction at an angle, where the resulting lift force and wake suction force cancel out the drag. Small motions of the caudal and/or pectoral fins provide an efficient way to correct the angle, such that an equilibrium is even reached in case of unsteadiness imposed by the wake of an object.
Phenotypic plasticity of gas exchange pattern and water loss in Scarabaeus spretus (Coleoptera: Scarabaeidae): deconstructing the basis for metabolic rate variation
Authors: Terblanche John S. , Clusella-Trullas Susana , Chown Steven L. 
Published: August 2010

SUMMARY
Investigation of gas exchange patterns and modulation of metabolism provide insight into metabolic control systems and evolution in diverse terrestrial environments. Variation in metabolic rate in response to environmental conditions has been explained largely in the context of two contrasting hypotheses, namely metabolic depression in response to stressful or resource-(e.g. water) limited conditions, or elevation of metabolism at low temperatures to sustain life in extreme conditions. To deconstruct the basis for metabolic rate changes in response to temperature variation, here we undertake a full factorial study investigating the longer- and short-term effects of temperature exposure on gas exchange patterns. We examined responses of traits of gas exchange [standard metabolic rate (SMR); discontinuous gas exchange (DGE) cycle frequency; cuticular, respiratory and total water loss rate (WLR)] to elucidate the magnitude and form of plastic responses in the dung beetle, Scarabaeus spretus. Results showed that short- and longer-term temperature variation generally have significant effects on SMR and WLR. Overall, acclimation to increased temperature led to a decline in SMR (from 0.071±0.004 ml CO2 h–1 in 15°C-acclimated beetles to 0.039±0.004 ml CO2 h–1 in 25°C-acclimated beetles measured at 20°C) modulated by reduced DGE frequency (15°C acclimation: 0.554±0.027 mHz, 20°C acclimation: 0.257±0.030 mHz, 25°C acclimation: 0.208±0.027 mHz recorded at 20°C), reduced cuticular WLRs (from 1.058±0.537 mg h–1 in 15°C-acclimated beetles to 0.900±0.400 mg h–1 in 25°C-acclimated beetles measured at 20°C) and reduced total WLR (from 4.2±0.5 mg h–1 in 15°C-acclimated beetles to 3.1±0.5 mg h–1 in 25°C-acclimated beetles measured at 25°C). Respiratory WLR was reduced from 2.25±0.40 mg h–1 in 15°C-acclimated beetles to 1.60±0.40 mg h–1 in 25°C-acclimated beetles measured at 25°C, suggesting conservation of water during DGE bursts. Overall, this suggests water conservation is a priority for S. spretus exposed to longer-term temperature variation, rather than elevation of SMR in response to low temperature acclimation, as might be expected from a beetle living in a relatively warm, low rainfall summer region. These results are significant for understanding the evolution of gas exchange patterns and trade-offs between metabolic rate and water balance in insects and other terrestrial arthropods.
Comparative jet wake structure and swimming performance of salps
Authors: Sutherland Kelly R. , Madin Laurence P. 
Published: August 2010

SUMMARYSalps are barrel-shaped marine invertebrates that swim by jet propulsion. Morphological variations among species and life-cycle stages are accompanied by differences in swimming mode. The goal of this investigation was to compare propulsive jet wakes and swimming performance variables among morphologically distinct salp species (Pegea confoederata, Weelia (Salpa) cylindrica, Cyclosalpa sp.) and relate swimming patterns to ecological function. Using a combination of in situ dye visualization and particle image velocimetry (PIV) measurements, we describe properties of the jet wake and swimming performance variables including thrust, drag and propulsive efficiency. Locomotion by all species investigated was achieved via vortex ring propulsion. The slow-swimming P. confoederata produced the highest weight-specific thrust (T=53 N kg–1) and swam with the highest whole-cycle propulsive efficiency (ηwc=55%). The fast-swimming W. cylindrica had the most streamlined body shape but produced an intermediate weight-specific thrust (T=30 N kg–1) and swam with an intermediate whole-cycle propulsive efficiency (ηwc=52%). Weak swimming performance variables in the slow-swimming C. affinis, including the lowest weight-specific thrust (T=25 N kg–1) and lowest whole-cycle propulsive efficiency (ηwc=47%), may be compensated by low energetic requirements. Swimming performance variables are considered in the context of ecological roles and evolutionary relationships.
Lusitanian toadfish song reflects male quality
Authors: Amorim M. Clara P. , Simões J. Miguel , Mendonça Nuno , Bandarra Narcisa M. , Almada Vitor C. , Fonseca Paulo J. 
Published: August 2010

SUMMARYLusitanian toadfish males that provide parental care rely on acoustic signals (the boatwhistle) to attract females to their nest. We test the hypothesis that male quality, namely male size and condition that are relevant for parental success, is reflected in vocal activity and boatwhistle characteristics and thus advertised to females. We recorded 22 males over a week during the peak of the breeding season. Calling rate and calling effort (percentage of time spent calling) strongly reflected male condition (lipid content of somatic muscles) and to a smaller extent sonic muscle hypertrophy and larger gonads. Males in better condition (increased body lipid and relative higher liver mass) also contracted the sonic muscles at faster rate as shown by the shorter boatwhistle pulse periods. Amplitude modulation reflected the degree of sonic muscle hypertrophy. None of the measured male quality parameters were good predictors of boatwhistle duration and dominant frequency. Altogether this study strongly suggests that Lusitanian toadfish males advertise their quality to females primarily with boatwhistle calling rate and calling effort, which mainly reflect male condition. Because pulse period had low variability, consistent with the existence of a vocal central pattern generator, we suggest that males that sustain sonic muscles contraction at a very fast rate close to their physiological limit may be honestly advertising their quality (condition). Similarly, males that produce boatwhistles with higher amplitude modulation, a feature that seems dependent on sonic muscle hypertrophy, could be more attractive to females.
Mentalizing, motivation, and social mentalities: Theoretical considerations and implications for psychotherapy
Authors: Liotti Giovanni , Gilbert Paul 
Published: August 2010

Background. Mentalization has recently been identified as a major process in the origins, maintenance, and recovery from various mental disorders.Aims. Questions arise however, as to the degree to which deficits in mentalization can be trait or state‐like: whether they manifest themselves across all types of human interaction, or are they relationship dependent, such that different types of relationship (e.g., affiliative vs. competitive) can facilitate or compromise mentalizing?Findings. This paper suggests that mentalization has a complex evolutionary history, has various subtypes and functions, is highly regulated by the experience of threat or safeness within relationships, and can operate differently in different types of social relationship.Implications. Awareness of this enables therapists to pay particular attention to the social roles and types of relationships in which mentalization occurs, its specific focus and functions for specific types of relationships. Therapists can be mindful of the kind of specific events in social roles that activate threat and loss of mentalizing (e.g., abandonment threats, feeling controlled by ‘the other’, status loss, non‐reciprocation).
Role of the second disulfide bridge (Cys18-Cys274) in stabilizing the inactive AT1 receptor
Authors: Martin Renan Paulo , da Silva Rodrigues Eliete , Correa Silvana Aparecida Alves , Oliveira Suzana Macedo , Mortara Renato Arruda , Oliveira Laerte , Nakaie Clovis Ryuichi , Shimuta Suma Imura 
Published: August 2010

AbstractPrevious research showed that disruption of the Cys18-Cys274bond in the angiotensin II (AngII) AT1receptor mutant (C18S), expressed in CHO cells, causes an increase in the basal activity and attenuation of the maximum response to AngII. In addition, this mutant was mostly intracellularly distributed. Our aim was to investigate whether the intracellular presence of the mutant was due to a constitutive internalization or to a defective maturation of the receptor. The first hypothesis was assessed by pretreating the cells with losartan or [Sar1Leu8]-AngII, specific AT1receptor antagonists, a maneuver to revert the receptor internalization. The second hypothesis was tested using calnexin, an endoplasmic reticulum marker. We found that treatment with AT1receptor antagonists causes an increase in the binding ability of the mutant to AngII. Furthermore, whereas the maximum effect is increased, it reduces the enhanced basal levels of IP3. The hypothesis for a lack of maturation of the mutant receptor was ruled out because calnexin was poorly colocalized with the intracellular C18S receptor. Our results suggest that the mutation of the AT1receptor leads to a conformational structure similar to that of the active mode of the AT1receptor, favoring its internalization in the absence of the agonist.
E. coli hypoxia-inducible factor ArcA mediates lifespan extension in a lipoic acid synthase mutant by suppressing acetyl-CoA synthetase
Authors: Gonidakis Stavros , Finkel Steven E. , Longo Valter D. 
Published: August 2010

AbstractWe have previously shown that both the hypoxia-inducible transcription factor ArcA and the PoxB/Acs bypass of the pyruvate dehydrogenase complex contribute to extended lifespan inEscherichia coli. In agreement with studies in higher eukaryotes, we also demonstrated that long-livedE. colimutants, including LipA-deficient cells, are stress resistant. Here, we show that ArcA contributes to the enhanced lifespan and heat shock resistance of thelipAmutant by suppressing expression of the acetyl-CoA synthetase (acs) gene. The deletion ofacsreversed the reduced lifespan of thelipA arcAmutant and promoted the accumulation of extracellular acetate, indicating that inhibition of carbon source uptake contributes to survival extension. However, Acs also sensitized cells lacking ArcA to heat shock, in the absence of extracellular acetate. These results provide evidence for the role of Acs in regulating lifespan and/or stress resistance by both carbon source uptake-dependent and -independent mechanisms.
Demonstration of protein absorption in the intestinal epithelium of fish and mice by laser scanning confocal microscopy
Authors: Yue Wan-fu , Zhou Fang , Malik Firdose Ahmad , Yang Hua-jun , Li Xing-hua , Roy Bhaskar , Reddy Srimivasa , Miao Yun-gen 
Published: August 2010

AbstractSelective permeability for small proteins and oligopeptides occurs in the intestinal epithelium of many animal species and humans. Whole proteins are sometimes endocytosed and undergo partial hydrolysis in intestinal epithelial cells with the probable release of essential oligopeptides into the bloodstream. Increased permeability to certain proteins can cause asthma and other metabolic disorders. Permeable proteins have also been successfully used to deliver vaccines or drugs via oral consumption. Protein absorption has been inferred in many cases and demonstrated in some cases by histochemical, tracer, and analytical techniques. However, the nature and importance of protein absorption remains largely unknown. Here, we demonstrate the movement of two lumenal proteins (GFP: 26 kDa and OFP: 23 kDa) across the intestinal epithelium of fish and mice using laser scanning confocal microscopy. The results provide evidence that small proteins can be taken up intact by intestinal epithelial cells, even though large proteins are digested to single amino acids or protein fragments before they are absorbed. Our results suggest that it is possible to orally administer some small proteinous medicines for therapeutic purposes.
Glucose homeostasis and insulin sensitivity in growth hormone-transgenic mice: a cross-sectional analysis
Authors: Boparai Ravneet K. , Arum Oge , Khardori Romesh , Bartke Andrzej 
Published: August 2010

AbstractIn contrast to its stimulatory effects on musculature, bone, and organ development, and its lipolytic effects, growth hormone (GH) opposes insulin effects on glucose metabolism. Chronic GH overexposure is thought to result in insulin insensitivity and decreased blood glucose homeostatic control. Yet, despite the importance of this concept for basic biology, as well as human conditions of GH excess or deficiency, no systematic assessment of the impact of GH over- expression on glucose homeostasis and insulin sensitivity has been conducted. We report that male and female adult GH transgenic mice have enhanced glucose tolerance compared to littermate controls and this effect is not dependent on age or on the particular heterologous GH transgene used. Furthermore, increased glucose-stimulated insulin secretion, augmented insulin sensitivity, and muted gluconeogenesis were also observed in bovine GH overexpressing mice. These results show that markedly increased systemic GH concentration in GH-transgenic mice exerts unexpected beneficial effects on glucose homeostasis, presumably via a compensatory increase in insulin release. The counterintuitive nature of these results challenges previously held presumptions of the physiology of these mice and other states of GH overexpression or suppression. In addition, they pose intriguing queries about the relationships between GH, endocrine control of metabolism, and aging.
Effect of homeostasis model assessment computational method on the definition and associations of insulin resistance
Authors: Mojiminiyi Olusegun A. , Abdella Nabila A. 
Published: August 2010

Abstract

Background: Homeostasis model assessment (HOMA) is a surrogate index widely used to study the role of insulin sensitivity or resistance in associated disease states. However, reported values for the definition of insulin resistance (the top 25% of the distribution in non-diabetic subjects) vary widely. This study evaluates the effect of HOMA computational methods [original HOMA model formula (HOMA1) and online calculator computer model (HOMA2)] on the associations and cut-off limits for insulin resistance.

Methods: Anthropometric measurements, fasting adiponectin, leptin, leptin receptor, insulin, glucose, high-sensitivity C-reactive protein and a lipid profile were measured in type 2 diabetic patients (n=226) and their normoglycemic first degree relatives (n=319). HOMA1 and HOMA2 were used to estimate insulin resistance, β-cell function and insulin sensitivity. Subjects were classified as metabolic syndrome positive or negative (International Diabetes Federation criteria). Bland-Altmann analysis was used to evaluate agreement between the computational methods. Univariate and multivariate logistic regression analyses were used to relate the HOMA computational methods with metabolic variables and metabolic syndrome status.

Results: The two computational methods had different cut-offs for the definition of insulin resistance: HOMA1 formula ≥2.5; HOMA2 calculator ≥1.4. Correlations of the two HOMA computational methods with anthropometric and metabolic variables showed some degree of variation. The odds ratios of the associations with the metabolic syndrome for the HOMA1 formula and HOMA2 calculator computational methods were 2.04 and 1.43, respectively. Receiver operating characteristic analysis for diagnosis of the metabolic syndrome showed that areas under the receiver operating characteristic curves for the HOMA1 formula and HOMA2 calculator computational methods were 0.741 and 0.680, respectively.

Conclusions: The HOMA computational method is a significant determinant of the associations and classification of insulin resistance.
Clin Chem Lab Med 2010;48:1629–34.
Designing Mixed Oxides Magnetic Nanoparticles for Sensing Applications
Authors: Sorescu Monica , Diamandescu L. , Tomescu A. , Krupa S. 
Published: August 2010

ABSTRACTZirconium-doped hematite particles of the type xZrO2-(1-x)α-Fe2O3 (x=0.1, 0.5) were synthesized using mechanochemical activation and characterized by X-ray diffraction (XRD) and Mössbauer spectroscopy. XRD patterns yielded the dependence of lattice parameters and particle size as a function of ball milling time for each value of the molar concentration x. The Mössbauer spectra were fitted with one or alternatively, four sextets, corresponding to Zr ions substituting Fe ions in the hematite structure and further required the addition of a quadrupole-split doublet, representing Fe substituting Zr in the ZrO2 lattice. We further correlated the structural properties of the zirconium-doped hematite system with the sensing properties. These were measured as function of temperature, gas concentration (carbon monoxide and methane) and variable humidity of air. The material system was found to be sensitive over the entire range of CO concentrations and the linearity of the sensor signal was not affected by the relative humidity of air, which makes it the ideal system for sensing devices. Comparative results obtained for tin-doped hematite nanoparticles are also presented.
Magnetic Nanostructures by Molecular Design: Synthetic Chemistry in Materials Research
Authors: Sandifer Jenn L. H. , Christou George 
Published: August 2010

ABSTRACTIn the field of nanostructured magnetic materials, the top-down approach of making ever-smaller magnetic particles has been successful in decreasing the minimum size of magnetic nanoparticles made in this way. Simultaneously, synthetic chemists have employed a “bottom-up” approach to the same problem through discovery of increasingly large molecular magnetic clusters that behave as individual magnets at low temperature. These molecules are called single-molecule magnets, and they have been discovered in a variety of sizes, up to 4 nanometers in diameter. Some display interesting solid-state properties in the crystalline state: bistability through hydrogen bonding or crystallization in potentially useful patterns, such as tubes. The advantage of discrete molecules as nanoscale magnets is the monodispersity of particle size. As the molecular approach and the materials approach to nanoscale magnets brings the possible sizes of particles by each method within range of the other, interdisciplinary research into the complementarity of the two approaches becomes necessary. The magnetism displayed by nanoparticles and molecules alike at this size shows both classical and quantum properties, uniting the two types of production as a window into this area bridging the two major ways of describing the physical world. A discussion of the progress of the synthetic chemistry approach and physics in this area will be made, as well as a discussion of how molecular chemistry may fit in to the field of magnetic nanostructures.
Structural and Magneto-transport Properties of Cr-doped In2O3 Diluted Magnetic Semiconductors
Authors: Ukah N.B. , Gupta R K , Ghosh K , Kahol P K , Giedd R 
Published: August 2010

AbstractWe report the experimental study of the structural and magnetotransport properties of chromium-doped indium oxide (In2O3:Cr) thin films using x-ray diffractometer, and by measuring the resistivity and Hall effect as a function of temperature in various magnetic fields. The In2O3:Cr diluted magnetic semiconductor thin films were grown under different partial oxygen pressures (Po2) on sapphire substrates using pulsed laser deposition (PLD) technique. Observed expansions in lattice parameter and crystal size in these films with increase in oxygen growth pressure are traceable to the reduction in oxygen vacancies. A redshift of the absorption edges of the samples with increase in oxygen growth pressure is attributed to the significant improvement in crystallinity. The exchange interaction between the electron spins in the conduction band and the spins of the Cr 3d electrons was evident in the anomalous Hall effect (AHE), which persisted up to 300 K. An analysis of the dc electrical transport in the films was carried out using hopping conduction and ionized impurity scattering models.