bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of small-scale inhomogeneities on the cosmological consistency tests
Authors: Busti V. C. , Lima J. A. S.
Published: August 2012

The current cosmological dark sector (dark matter plus dark energy) is challenging our comprehension about the physical processes taking place in the Universe. Recently, some authors tried to falsify the basic underlying assumptions of such dark matter–dark energy paradigm. In this Letter, we show that oversimplifications of the measurement process may produce false positives to any consistency test based on the globally homogeneous and isotropic Λ cold dark matter (ΛCDM) model and its expansion history based on distance measurements. In particular, when local inhomogeneity effects due to clumped matter or voids are taken into account, an apparent violation of the basic assumptions (‘Copernican Principle’) seems to be present. Conversely, the amplitude of the deviations also probes the degree of reliability underlying the phenomenological Dyer–Roeder procedure by confronting its predictions with the accuracy of the weak lensing approach. Finally, a new method is devised to reconstruct the effects of the inhomogeneities in a ΛCDM model, and some suggestions of how to distinguish between clumpiness (or void) effects from different cosmologies are discussed.
Calibrating a Salt Water Intrusion Model with Time‐Domain Electromagnetic Data
Authors: Herckenrath Daan , Odlum Nick , Nenna Vanessa , Knight Rosemary , Auken Esben , Bauer‐Gottwein Peter
Published: August 2012

Salt water intrusion models are commonly used to support groundwater resource management in coastal aquifers. Concentration data used for model calibration are often sparse and limited in spatial extent. With airborne and ground‐based electromagnetic surveys, electrical resistivity models can be obtained to provide high‐resolution three‐dimensional models of subsurface resistivity variations that can be related to geology and salt concentrations on a regional scale. Several previous studies have calibrated salt water intrusion models with geophysical data, but are typically limited to the use of the inverted electrical resistivity models without considering the measured geophysical data directly. This induces a number of errors related to inconsistent scales between the geophysical and hydrologic models and the applied regularization constraints in the geophysical inversion. To overcome these errors, we perform a coupled hydrogeophysical inversion (CHI) in which we use a salt water intrusion model to interpret the geophysical data and guide the geophysical inversion. We refer to this methodology as a Coupled Hydrogeophysical Inversion‐State (CHI‐S), in which simulated salt concentrations are transformed to an electrical resistivity model, after which a geophysical forward response is calculated and compared with the measured geophysical data. This approach was applied for a field site in Santa Cruz County, California, where a time‐domain electromagnetic (TDEM) dataset was collected. For this location, a simple two‐dimensional cross‐sectional salt water intrusion model was developed, for which we estimated five uniform aquifer properties, incorporating the porosity that was also part of the employed petrophysical relationship. In addition, one geophysical parameter was estimated. The six parameters could be resolved well by fitting more than 300 apparent resistivities that were comprised by the TDEM dataset. Except for three sounding locations, all the TDEM data could be fitted close to a root‐mean‐square error of 1. Possible explanations for the poor fit of these soundings are the assumption of spatial uniformity, fixed boundary conditions and the neglecting of 3D effects in the groundwater model and the TDEM forward responses.
Evidence‐based practice for the busy nurse practitioner: Part two: Searching for the best evidence to clinical inquiries
Authors: Facchiano Lynda , Snyder Charlene Hoffman
Published: August 2012

Purpose: The purpose of this four‐part evidence‐based practice (EBP) series is to enhance the nurse practitioner's (NP's) EBP skills by reviewing the process of developing a clinical question, searching for the best evidence, and critically appraising and applying the findings. Part two of the series focuses on how to search the published scientific literature for the most relevant studies that will answer a specific clinical question of importance to the NP.

Data sources: Scientific literature review, gray searching, PubMed and other online literature databases and resources, and online EBP websites.

Conclusions: Technology has allowed multiple healthcare resources to be available at one's fingertips enabling both NPs and their patients to find answers to clinical questions. EBP databases can be categorized as synthesized/filtered, unfiltered, and background information/expert opinion resources. Learning which database can best answer the clinical inquiry can streamline the search process.

Implications for practice: For the busy NP, EBP has emerged as an important strategy to maintain valid, accurate, and relevant clinical knowledge. It is expected that this part of the series will enable NPs to identify appropriate databases to answer clinical inquires while refining their search strategy skills, which takes both time and practice.
Assessment of provider adherence to obesity treatment guidelines
Authors: Farran Nicole , Ellis Peggy , Lee Barron Mary
Published: August 2012

Purpose

Despite the presence of obesity treatment guidelines, healthcare providers often provide suboptimal weight management. The purpose of the quality improvement project was to systematically assess adherence with adult overweight/obesity guidelines in primary care to reduce patient risk.

Data sources

Retrospective analysis of 420 encounter notes from overweight and obese adult patients in three primary care clinics. Data were collected before and after a continuing education session for providers on guidelines for optimal management of obesity. Measures of completeness of quality indicators were abstracted from records.

Conclusions

Significant improvement in the completeness score and documentation of body mass index, height, diagnosis of overweight/obesity, and counseling for diet and physical activity were achieved.

Implications for practice

The proposed measures for systematically assessing the integration of obesity guidelines in primary care are feasible quality indicators and useful for evidence‐based decision making.
Obstructive sleep apnea hypopnea syndrome and metabolic syndrome: A synergistic cardiovascular risk factor
Authors: Goodson Becky Lynn , Wung Shu‐Fen , Archbold Kristen Hedger
Published: August 2012

Purpose: Cardiovascular disease (CVD) is the leading cause of morbidity and mortality for adults in the United States. One risk factor for CVD is metabolic syndrome, which encompasses obesity, hypertension, insulin resistance, proinflammatory state, and prothrombotic state. A lesser‐understood risk factor is obstructive sleep apnea hypopnea syndrome (OSAHS). This article explores the physiological consequences of the interaction between OSAHS and metabolic syndrome on the cardiovascular system.

Data sources: Search terms “metabolic syndrome,”“obstructive sleep apnea,”“cardiovascular disease,”“diabetes,”“obesity,” and “atherosclerosis,” were used. Studies involving children were excluded.

Conclusions: Both metabolic syndrome and OSAHS have significant impact on the cardiovascular system; however, when both conditions are present together, the impact is synergistic and CVD risk is multiplied. Treatment with continuous positive airway pressure (CPAP) reduces the global burden of CVD risk.

Implications for practice: Providers need to screen patients routinely for both metabolic syndrome and OSAHS. Treatment should include CPAP, weight reduction, oral appliances, and/or upper airway surgeries with concurrent management for metabolic syndrome. Future research should further elucidate the mechanisms of action by which OSAHA and metabolic syndrome contribute to CVD. This understanding can lead to more stringent guidelines on the management of metabolic syndrome and OSAHS.
“I got caught up in the game”: Generational influences on contraceptive decision making in African–American women
Authors: Harris Allyssa L.
Published: August 2012

Purpose

Reproductive health disparities are a significant issue for African–American adolescents. This study was designed to explore the cross‐generational influences on adolescent sexuality in a cohort of daughters/granddaughters of U.S. born African–American women.

Data sources

Data were generated through interviews with triads of African–American women: grandmothers, and their daughters and granddaughters, to gain insight into the phenomena of early sexual debut, high rates of unintended pregnancies, HIV/AIDS, and other sexually transmitted infections from a cross‐generational perspective.

Conclusions

Six themes emerged from the data: southern influences; a worldview of relationships; communication–key to preparedness; seeking information from mom; “I got caught up in the game”; and contraceptive use and beliefs. In this sample, mothers’ and grandmothers’ culture, values, and beliefs significantly influenced the adolescents’ sexual and reproductive decision making.

Implications for practice

Clinicians' knowledge of African–American culture, beliefs, and family values is key when providing guidance about contraception to these young women.
Home and heterosexuality in Aotearoa New Zealand: The spaces and practices of DIY and home renovation
Authors: Morrison Carey‐Ann
Published: August 2012

The ways in which domestic spaces function as sites of sexual subjectivity and relationship formation for heterosexual couples is an understudied area in geography. One way to address this gap in knowledge is to focus attention on the varied ways in which heterosexual couples use the practices and spaces of do‐it‐yourself (DIY) and home renovation to construct, materialise and sometimes disrupt their subjectivities and relationships. Taking into consideration the significance of home ownership in New Zealand, I argue that the practices of DIY and home renovations are an everyday event that can occur both within the dwelling and beyond. A focus on heterosexuality, home, DIY and home renovation encourages a more nuanced reading of the mutually constitutive relationship between bodies and spaces.
‘Troubling’ gender in virtual gaming spaces
Authors: Todd Cherie
Published: August 2012

This article considers the relationship between gaming and gender, and explores how eight mature women gamers (30 years of age and older), living in the Waikato region of New Zealand negotiate their ‘real‐life’ identities with their ‘virtual’ gaming identities. In particular, performances of ‘gender‐bending’ in gaming are examined and Butler's notion of ‘gender trouble’ is drawn upon to look at the ways in which ‘gender‐bending’ disrupts and/or reinforces hegemonic binary distinctions of gender – masculinity/femininity and man/woman. This article concludes by arguing that gender‐switching within gaming spaces is a normative practice within gaming culture, and as such, acts of ‘gender‐bending’ do very little to challenge or ‘bend’ dominant notions of gender within the spaces of mainstream gaming.
Sexuality, space and migration: South Asian gay men in Australia
Authors: Smith Geoffrey
Published: August 2012

This paper investigates the relationship between migration, private space and sexual expression for South Asian gay men who have relocated to Melbourne, Australia. Little is known about South Asian gay men who have moved to Australia, or the role of mobility and spatial setting in constituting their sexualities. To tackle this gap, 23 South Asian gay men (21–50 years old) living in Melbourne were interviewed. This paper discusses emergent themes on the contribution of migration and private space to constituting sexual identities. Cultural expectations for marriage, social stigma about homosexuality and a lack of private spaces for sexual exploration, constrained the participants' sexual expression in South Asia. These factors underpinned some men's migration decisions. But while living away from family and country of origin provide private spaces and greater freedom, ‘coming out’ and expressing homosexual interests within private domestic space in Australia is not always easy or possible.
Diffuse Reflectance Spectroscopy as a Tool to Measure the Absorption Coefficient in Skin: South African Skin Phototypes
Authors: Karsten Aletta E. , Singh Ann , Karsten Petrus A. , Braun Max W. H.
Published: August 2012

In any laser skin treatment, the optical properties (absorption and scattering coefficients) are important parameters. The melanin content of skin influences the absorption of light in the skin. The spread in the values of the absorption coefficients for the South African skin phototypes are not known. A diffuse reflectance probe consisting of a ring of six light delivery fibers and a central collecting fiber was used to measure the diffused reflected light from the arms of 30 volunteers with skin phototypes I–V (on the Fitzpatrick scale). The absorption coefficient was calculated from these measurements. This real‐time in vivo technique was used to determine the absorption coefficient of sun‐exposed and ‐protected areas on the arm. The range of typical absorption coefficients for the South African skin phototypes is reported. The values for the darker South African skin types were much higher than was previously reported for darker skin phototypes. In the analysis, the contributions of the eumelanin and pheomelanin were separated, which resulted in improved curve fitting for volunteers of southern Asian ethnicity without compromising the other groups.
Photosynthesis Assessment in Microphytobenthos Using Conventional and Imaging Pulse Amplitude Modulation Fluorometry
Authors: Vieira Sónia , Ribeiro Lourenço , Jesus Bruno , Cartaxana Paulo , Silva Jorge Marques da
Published: August 2012

Imaging pulse amplitude modulated (Imaging‐PAM) fluorometry is a breakthrough in the study of spatial heterogeneity of photosynthetic assemblages. However, Imaging and conventional PAM uses a different technology, making comparisons between these techniques doubtful. Thereby, photosynthetic processes were comparatively assessed using conventional (Junior PAM and PAM 101) and Imaging‐PAM on intertidal microphytobenthos (MPB; mud and sand) and on cork oak leaves. Lower values of α (initial slope of the rETR, relative photosynthetic electron transport rate) vs E (incident photosynthetic active radiation) curve), ETRmax (maximum relative ETR), Ek (light saturation parameter) and Fv/Fm (maximum quantum efficiency of photosystem II of dark‐adapted samples) were obtained using the Imaging‐PAM. The level of discrepancy between conventional and Imaging‐PAM systems was dependent on the type of sample, being more pronounced for MPB muddy sediments. This may be explained by differences in the depth integration of the fluorescence signal related to the thickness of the photosynthetic layer and in the light attenuation coefficients of downwelling irradiance. An additional relevant parameter is the taxonomic composition of the MPB, as cyanobacteria present in sandy sediments rendered different results with red and blue excitation light fluorometers. These findings emphasize the caution needed when interpreting chlorophyll fluorescence data of MPB communities.
Modulation of Lipopolysaccharide‐Induced NF‐κB Signaling Pathway by 635 nm Irradiation via Heat Shock Protein 27 in Human Gingival Fibroblast Cells
Authors: Lim WonBong , Kim JiSun , Kim SangWoo , Karna Sandeep , Won JaeWoong , Jeon Sang Mi , Kim Seo Yeon , Choi YooDuk , Choi HongRan , Kim OkJoon
Published: August 2012

Heat shock protein‐27 (HSP27) is a member of the small HSP family which has been linked to the nuclear factor‐kappa B (NF‐κB) signaling pathway regulating inflammatory responses. Clinical reports have suggested that low‐level light therapy/laser irradiation (LLLT) could be an effective alternative treatment to relieve inflammation during bacterial infection associated with periodontal disease. However, it remains unclear how light irradiation can modulate the NF‐κB signaling pathway. We examined whether or not 635 nm irradiation could lead to a modulation of the NF‐kB signaling pathway in HSP27‐silenced cells and analyzed the functional cross‐talk between these factors in NF‐κB activation. The results showed that 635 nm irradiation led to a decrease in the HSP27 phosphorylation, reactive oxygen species (ROS) generation, I‐κB kinase (IKK)/inhibitor of κB (IκB)/NF‐κB phosphorylation, NF‐κB p65 translocation and a subsequent decrease in the COX‐1/2 expression and prostaglandin (PGE2) release in lipopolysaccharide(LPS)‐induced human gingival fibroblast cells (hGFs). However, in HSP27‐silenced hGFs, no obvious changes were observed in ROS generation, IKK/IκB/NF‐κB phosphorylation, NF‐κB p65 translocation, nor in COX‐1/2 expression, or PGE2 release. This could be a mechanism by which 635 nm irradiation modulates LPS‐induced NF‐κB signaling pathway via HSP27 in inflammation. Thus, HSP27 may play a role in regulating the anti‐inflammatory response of LLLT.
The Meaning of Embodiment
Authors: Kiverstein Julian
Published: August 2012

There is substantial disagreement among philosophers of embodied cognitive science about the meaning of embodiment. In what follows, I describe three different views that can be found in the current literature. I show how this debate centers around the question of whether the science of embodied cognition can retain the computer theory of mind. One view, which I will label body functionalism, takes the body to play the functional role of linking external resources for problem solving with internal biological machinery. Embodiment is thus understood in terms of the role the body plays in supporting the computational circuits that realize cognition. Body enactivism argues by contrast that no computational account of cognition can account for the role of commonsense knowledge in our everyday practical engagement with the world. I will attempt a reconciliation of these seemingly opposed views.
Calcium spike variability in cardiac myocytes results from activation of small cohorts of ryanodine receptor 2 channels
Authors: Janíček Radoslav , Zahradníková Jr Alexandra , Poláková Eva , Pavelková Jana , Zahradník Ivan , Zahradníková Alexandra
Published: August 2012

Key points

Cardiac myocytes contract due to the upsurge in intracellular calcium concentration resulting from the activation of ryanodine receptor (RyR) channels residing at calcium releasing sites.

Calcium release can be observed as local calcium spikes that vary in amplitude, time course and frequency of occurrence due to reasons that are not well understood.

In this study we quantify the characteristics of calcium spikes in isolated myocytes, typify them by stochastic analysis and interpret them by mathematical modelling.

We show that the observable properties of calcium spikes are compatible with gating properties, calcium/magnesium sensitivity and distribution of RyR channels, if only a few out of the many RyRs clustered at the release sites activate at a single release event.

The proposed mechanism of stimulated calcium release clarifies the concepts of the structure and function of calcium releasing sites and of plasticity and dynamics of calcium signalling in cardiac development and disease.

Abstract  In mammalian cardiac myocytes, the elementary calcium releases triggered by step voltage stimuli manifest either as solitary or as twin spikes that vary widely in kinetics and amplitude for unknown reasons. Here we examined the variability of calcium spikes measured using line‐scanning confocal microscopy in patch‐clamped rat ventricular myocytes. Amplitude distributions of the single and of the first of twin spikes were broader than those of the second spikes. All could be best approximated by a sum of a few elementary Gaussian probability distribution functions. The latency distributions of the single and the first spikes were identical, much shorter and less variable than those of the second spikes. The multimodal distribution of spike amplitudes and the probability of occurrence of twin spikes were stochastically congruent with activation of only a few of the many RyR2 channels present in the release site cluster. The occurrence of twin release events was rare due to refractoriness of release, induced with a probability proportional to the number of RyR2s activated in the primary release event. We conclude that the variability of the elementary calcium release events supports a calcium signalling mechanism that arises from stochastics of RyR2 gating and from inactivation of local origin.
Muscarinic control of AMPA receptor responsiveness in mouse spinal cord motoneurons
Authors: Mejia‐Gervacio Sheyla
Published: August 2012

Key points

The muscarinic receptors increase the excitability in spinal cord motoneurons.

In the present study, I report the muscarinic modulation of postsynaptic AMPA receptors at glutamatergic synapses on spinal cord motoneurons.

The muscarinic modulation acts specifically on synapses originated at the dorsolateral funiculus, which contains supraspinal and spinal intersegmental influences.

The present results suggest that the modulatory actions of muscarinic receptors reduce the synaptic weight of excitatory inputs originating at intersegmental and/or supraspinal levels but not at the intrasegmental level.

The muscarinic receptor activity might amplify the differences between synaptic weights of inputs with different origins, potentially contributing to the diversity of motor outputs implicating the same muscular groups, as well as to the refinement of locomotor behaviour at early postnatal stages.

Abstract  A cholinergic synaptic input has been highlighted in recent years as an important modulator of motoneuron excitability. In the present study, it was examined whether, as in other regions, the cholinergic inputs on spinal motoneurons modulate the glutamatergic synaptic activity, evoked by electrical stimulation at the dorsolateral funiculus. The present results show that the pharmacological stimulation of muscarinic receptors produces a selective depression of AMPA‐mediated glutamatergic activity in thoracic and lumbar spinal motoneurons. This effect does not involve a change in transmitter release and occurs both on synaptic currents and on AMPA responses evoked by photolysis of MNI‐glutamate. Thus, it is concluded that muscarinic modulation occurs at the postsynaptic level. The results suggest that cholinergic inputs contacting motoneurons, which are known to increase motoneuron excitability, also directly interfere with incoming synaptic inputs by changing their amplitudes.
Exercise‐ and training‐induced upregulation of skeletal muscle fatty acid oxidation are not solely dependent on mitochondrial machinery and biogenesis
Authors: Yoshida Yuko , Jain Swati S. , McFarlan Jay T. , Snook Laelie A. , Chabowski Adrian , Bonen Arend
Published: August 2012

Abstract  Regulation of skeletal muscle fatty acid oxidation (FAO) and adaptation to exercise training have long been thought to depend on delivery of fatty acids (FAs) to muscle, their diffusion into muscle, and muscle mitochondrial content and biochemical machinery. However, FA entry into muscle occurs via a regulatable, protein‐mediated mechanism, involving several transport proteins. Among these CD36 is key. Muscle contraction and pharmacological agents induce CD36 to translocate to the cell surface, a response that regulates FA transport, and hence FAO. In exercising CD36 KO mice, exercise duration (−44%), and FA transport (−41%) and oxidation (−37%) are comparably impaired, while carbohydrate metabolism is augmented. In trained CD36 KO mice, training‐induced upregulation of FAO is not observed, despite normal training‐induced increases in mitochondrial density and enzymes. Transfecting CD36 into sedentary WT muscle (+41%), comparable to training‐induced CD36 increases (+44%) in WT muscle, markedly upregulates FAO to rates observed in trained WT mice, but without any changes in mitochondrial density and enzymes. Evidently, in vivo CD36‐mediated FA transport is key for muscle fuel selection and training‐induced FAO upregulation, independent of mitochondrial adaptations. This CD36 molecular mechanism challenges the view that skeletal muscle FAO is solely regulated by muscle mitochondrial content and machinery.
Lifelong physical activity prevents an age‐related reduction in arterial and skeletal muscle nitric oxide bioavailability in humans
Authors: Nyberg Michael , Blackwell James R. , Damsgaard Rasmus , Jones Andrew M. , Hellsten Ylva , Mortensen Stefan P.
Published: August 2012

Key points

Ageing has been proposed to be associated with increased levels of reactive oxygen species (ROS) that scavenge nitric oxide (NO), thereby decreasing the bioavailability of this potent vasodilator.

Here we show that NO bioavailability is compromised in the systemic circulation and in skeletal muscle of sedentary older humans as evidenced by an increase in NO metabolites after antioxidant infusion.

Lifelong physical activity opposes this effect within the trained musculature and in the arterial circulation.

The reduced blood flow to contracting leg muscles with ageing does not appear to be related to changes in NO bioavailability.

These findings expand our understanding of the mechanisms underlying the age‐related changes in vascular function and highlight the beneficial effect of exercise training throughout the lifespan.

Abstract  Ageing has been proposed to be associated with increased levels of reactive oxygen species (ROS) that scavenge nitric oxide (NO). In eight young sedentary (23 ± 1 years; Y), eight older lifelong sedentary (66 ± 2 years; OS) and eight older lifelong physically active subjects (62 ± 2 years; OA), we studied the effect of ROS on systemic and skeletal muscle NO bioavailability and leg blood flow by infusion of the antioxidant N‐acetylcysteine (NAC). Infusion of NAC increased the bioavailability of NO in OS, as evidenced by an increased concentration of stable metabolites of NO (NOx) in the arterial and venous circulation and in the muscle interstitium. In OA, infusion of NAC only increased NOx concentrations in venous plasma whereas in Y, infusion of NAC did not affect NOx concentrations. Skeletal muscle protein levels of endothelial and neuronal NO synthase were 32% and 24% higher, respectively, in OA than in OS. Exercise at 12 W elicited a lower leg blood flow response that was associated with a lower leg oxygen uptake in OS than in Y. The improved bioavailability of NO in OS did not increase blood flow during exercise. These data demonstrate that NO bioavailability is compromised in the systemic circulation and in the musculature of sedentary ageing humans due to increased oxidative stress. Lifelong physical activity opposes this effect within the trained musculature and in the arterial circulation. The lower blood flow response to leg exercise in ageing humans is not associated with a reduced NO bioavailability.
Spreading the signal for vasodilatation: implications for skeletal muscle blood flow control and the effects of ageing
Authors: Behringer Erik J. , Segal Steven S.
Published: August 2012

Abstract  Blood flow control requires coordinated contraction and relaxation of smooth muscle cells (SMCs) along and among the arterioles and feed arteries that comprise vascular resistance networks. Whereas smooth muscle contraction of resistance vessels is enhanced by noradrenaline release along perivascular sympathetic nerves, the endothelium is integral to coordinating smooth muscle relaxation. Beyond producing nitric oxide in response to agonists and shear stress, endothelial cells (ECs) provide an effective conduit for conducting hyperpolarization along vessel branches and into surrounding SMCs through myoendothelial coupling. In turn, bidirectional signalling from SMCs into ECs enables the endothelium to moderate adrenergic vasoconstriction in response to sympathetic nerve activity. This review focuses on the endothelium as the cellular pathway that coordinates spreading vasodilatation. We discuss the nature and regulation of cell‐to‐cell coupling through gap junctions, bidirectional signalling between ECs and SMCs, and how oxidative stress during ageing may influence respective signalling pathways. Our recent findings illustrate the role of small (SKCa) and intermediate (IKCa) Ca2+ activated K+ channels as modulators of electrical conduction along the endothelium. Gaps in current understanding indicate the need to determine mechanisms that regulate intracellular Ca2+ homeostasis and ion channel activation in the resistance vasculature with advancing age.
Altered pallido‐pallidal synaptic transmission leads to aberrant firing of globus pallidus neurons in a rat model of Parkinson's disease
Authors: Miguelez Cristina , Morin Stéphanie , Martinez Audrey , Goillandeau Michel , Bezard Erwan , Bioulac Bernard , Baufreton Jérôme
Published: August 2012

Key points

We used optogenetics approach to characterize the short‐term plasticity of striato‐pallidal (STR–GP) and pallido‐pallidal (GP–GP) GABAergic synapses in rat brain slices.

We show that only GP–GP (and not STR–GP) transmission is augmented by chronic dopamine depletion.

Finally, we report that altered GP–GP synaptic transmission promotes neuronal synchronization and rebound bursting in globus pallidus neurons.

Our results support the conclusion that maladaptive GP–GP GABAergic transmission is likely to be a key underlying factor of the pathological activity in the globus pallidus observed in Parkinson's disease.

Abstract  The pattern of activity of globus pallidus (GP) neurons is tightly regulated by GABAergic inhibition. In addition to extrinsic inputs from the striatum (STR–GP) the other source of GABA to GP neurons arises from intrinsic intranuclear axon collaterals (GP–GP). While the contribution of striatal inputs has been studied, notably its hyperactivity in Parkinson's disease (PD), the properties and function of intranuclear inhibition remain poorly understood. Our objective was therefore to test the impact of chronic dopamine depletion on pallido‐pallidal transmission. Using patch‐clamp whole‐cell recordings in rat brain slices, we combined electrical and optogenetic stimulations with pharmacology to differentiate basic synaptic properties of STR–GP and GP–GP GABAergic synapses. GP–GP synapses were characterized by activity‐dependent depression and insensitivity to the D2 receptor specific agonist quinpirole and STR–GP synapses by frequency‐dependent facilitation and quinpirole modulation. Chronic dopamine deprivation obtained in 6‐OHDA lesioned animals boosted the amplitude of GP–GP IPSCs but did not modify STR–GP transmission and increased the amplitude of miniature IPSCs. Replacement of calcium by strontium confirmed that the quantal amplitude was increased at GP–GP synapses. Finally, we demonstrated that boosted GP–GP transmission promotes resetting of autonomous activity and rebound‐burst firing after dopamine depletion. These results suggest that GP–GP synaptic transmission (but not STR–GP) is augmented by chronic dopamine depletion which could contribute to the aberrant GP neuronal activity observed in PD.
Laminar Film Condensation on a Nanosphere
Authors: Esfahani J. A. , Koohi-Fayegh S.
Published: August 2012

The present work investigates an analytical study on the problem of laminar film condensation on a nanosphere. Due to the microscale interaction, the problem is analyzed by taking into account the effects of slip in velocity and jump in temperature. A relation is derived for the liquid film thickness in the form of a nonlinear differential equation which is solved numerically using the fourth order Runge–Kutta method. Finally, the effect of velocity slip and temperature jump on different condensation parameters including the liquid film thickness, velocity and temperature profiles, Nusselt number, and liquid mass flow rate is discussed. It is found that the increase in the velocity slip and temperature jump results in a thinner liquid film and therefore increases the heat transfer coefficient.
PEDOT:PSS/SWCNTs as a Transparent Electrode for Organic Photovoltaic Devices
Authors: Derouiche Hassen , Mohamed Abdellatif Belhadj
Published: August 2012

We have fabricated a flexible organic solar cells, with an active layer of poly(3-hexylthiophene) (P3HT) blended with Fullerene derivative [6,6]-phenyl–C61–butyric acid methyl ester (PCBM) which was deposited by spin coating. The poly(3,4-ethylene dioxythiophene) poly(4-styrenesulfonate) (PEDOT:PSS), doped with ethylene glycol (EG) and single wall carbon nanotubes (SWCNTs), is heavily doped and therefore used as conductive transparent electrode rather than electron blocking layer. Likewise, we have deposited a layer of PEDOT:PSS/SWCNTs by spin coating. This layer is coated onto polyethylene terephthalate (PET) substrates. We have also compared the photovoltaic characteristics of the two different structures with PEDOT:PSS/SWCNTs or PEDOT:PSS/SWCNTs/PEDOT:PSS photoanode. Both structures show significant photovoltaic behavior. However, the power conversion efficiency has been scaled up from 1.02% to 1.93% resulting from the use of second layer of PEDOT:PSS.
Contribution to the Modeling and Understanding of Cold Pulsating Flow Influence in the Efficiency of Small Radial Turbines for Turbochargers
Authors: Serrano J. R. , Arnau F. J. , Fajardo P. , Reyes Belmonte M. A. , Vidal Fabrice
Published: August 2012

In the present paper, an unsteady approach to determine the performance of a small radial inflow turbine working under cold pulsating flow is presented. It has been concluded that a reasonably good characterization of turbine behavior working with pulsating flow can be obtained using, in a quasi-steady way, models of the turbine isentropic efficiency and turbocharger mechanical efficiency. Both models have been fitted using data obtained from a steady flow characterization procedure. Turbocharger-measured parameters from the cold pulsating flow campaign have been compared with the ones obtained from one-dimensional gas dynamics computational modeling. The modeling approach is based on quasi-steady isentropic and mechanical efficiency models. Reasonably good accuracy in compressor and turbine variables prediction has been obtained for most of the operative conditions. Influence of amplitude and frequency of the pulsating flow over the instantaneous and average turbine efficiency has been studied to put some light on the analysis of the involved physical phenomena. The main conclusion is that the biggest effect of unsteady flow on turbine efficiency is through the influence on blade jet to speed ratio. It has been also concluded that, for the same average blade jet to speed ratio, pulses’ amplitude does not influence turbine efficiency when it is closed, but does at other variable geometry turbine (VGT) positions. The effect of pulses’ frequency is less evident and only influences VGT performance at the highest VGT openings.
Simulation Based Design and Evaluation of a Transcatheter Mitral Heart Valve Frame
Authors: Young Melissa , Erdemir Ahmet , Stucke Samantha , Klatte Ryan , Davis Brian , Navia Jose L.
Published: August 2012

In certain populations, open heart surgery to replace a diseased mitral valve is not an option, leaving percutaneous delivery a viable alternative. However, a surgical transcatheter based delivery of a metallic support frame incorporating a tissue derived valve puts considerable constraints on device specifications. Expansion to a large diameter from the catheter diameter without mechanical fracture involves advanced device design and appropriate material processing and selection. In this study, a new frame concept is presented with a desirable feature that incorporates wings that protrude during expansion to establish adequate fixation. Expansion characteristics of the design in relation to annulus fixation were quantified through finite element analysis predictions of the frame wing span and angles. Computational modeling and simulation was used to identify many favorable design features for the transcatheter mitral valve frame and obtain desired expansion diameters (35–45 mm), acceptable radial stiffness (2.7 N/mm), and ensure limited risk of failure based on predicted plastic deformations.
ROBOImplant II: Development of a Noninvasive Controller/Actuator for Wireless Correction of Orthopedic Structural Deformities
Authors: Liu Jonathan A. , Etemadi Mozziyar , Heller James A. , Kwiat Dillon , Fechter Richard , Harrison Michael R. , Roy Shuvo
Published: August 2012

An implantable actuator and its accompanying driver circuit are presented for the purpose of lengthening bones and correcting skeletal deformities without requiring physical contact between the operator and the implanted device. This system utilizes magnetic coupling to form a magnetic gear, allowing an external motor to drive an implantable telescoping rod. The accompanying electronics are able to monitor the progress, in the form of turns delivered, as well as detect procedural errors, such as magnet decoupling. The force applied by the implanted telescoping rod can be accurately measured by monitoring the current necessary for the external controller to drive the extension of the implanted rod. After characterization, the system was shown to reliably deliver extension distances within 34 μm and maintain coupling out to 70 mm. The system is also able to measure torques as low as 0.12 mN m. System variability and accuracy of external monitoring are addressed.
Science Signaling
Podcast: 14 August 2012
Authors: Emlen Douglas J. , VanHook Annalisa M.
Published: August 2012

Growth of the male rhinoceros beetle’s horn is more sensitive to insulin signaling than are other body parts.
How Diet and Sun Promote Inflammation
Authors: Wong Wei
Published: August 2012

Endogenously produced danger-associated molecular patterns induced by free fatty acids and sun-damaged RNAs activate TLR4 and TLR3.
Cancer Stem Cells in Color
Authors: Kiberstis Paula A.
Published: August 2012

Multicolor reporter genes signal the fate of stem cells that fuel the growth of intestinal tumors in mice.
Crucial Cerebellar Glial Cells
Authors: Stern Peter R.
Published: August 2012

Signaling by glial cells helps to preserve cerebellar neurons that control movements.
Characterization of Poliovirus Variants Selected for Resistance to the Antiviral Compound V-073
Authors: Liu Hong-Mei , Roberts Jason A. , Moore Deborah , Anderson Barbara , Pallansch Mark A. , Pevear Daniel C. , Collett Marc S. , Oberste M. Steven
Published: August 2012

V-073, a small-molecule capsid inhibitor originally developed for nonpolio enterovirus indications is considerably more potent against polioviruses. All poliovirus isolates tested to date (
n
= 45), including wild, vaccine, vaccine-derived, and laboratory strains, are susceptible to the antiviral capsid inhibitor V-073. We grew poliovirus in the presence of V-073 to allow for the identification of variants with reduced susceptibility to the drug. Sequence analysis of 160 independent resistant variants (80 isolates of poliovirus type 1, 40 isolates each of types 2 and 3) established that V-073 resistance involved a single amino acid change in either of two virus capsid proteins, VP1 (67 of 160 [42%]) or VP3 (93 of 160 [58%]). In resistant variants with a VP1 change, the majority (53 of 67 [79%]) exhibited a substitution of isoleucine at position 194 (equivalent position 192 in type 3) with either methionine or phenylalanine. Of those with a VP3 change, alanine at position 24 was replaced with valine in all variants (
n
= 93). The resistance phenotype was relatively stable upon passage of viruses in cell culture in the absence of drug. Single-step growth studies showed no substantial differences between drug-resistant variants and the virus stocks from which they were derived, while the resistant viruses were generally more thermally labile than the corresponding drug-susceptible parental viruses. These studies provide a foundation from which to build a greater understanding of resistance to antiviral compound V-073.
Rapid Microarray-Based Identification of Different
mecA
Alleles in Staphylococci
Authors: Monecke Stefan , Müller Elke , Schwarz Stefan , Hotzel Helmut , Ehricht Ralf
Published: August 2012

To screen isolates and to identify
mecA
alleles, published
mecA
sequences were analyzed, and a microarray for the rapid discrimination of
mecA
alleles was designed. A GenBank analysis yielded 135 full-length gene sequences annotated as
mecA
. These sequences clustered into 32 different alleles corresponding to 28 unique amino acid sequences and to 15 distinct hybridization patterns on this microarray. A collection of 78 clinical and veterinary isolates of
Staphylococcus
spp. was characterized using this assay. Nine of the 15 expected patterns, as well as one as-yet-unknown pattern, were identified. These patterns were detected in various epidemic methicillin-resistant
Staphylococcus aureus
strains, in
S. pseudintermedius
, and in coagulase-negative species such as
S. epidermidis
,
S. fleurettii
, or
S. haemolyticus
. There was no correlation between the different
mecA
hybridization patterns and the SCC
mec
type. Determination of MICs showed that
mecA
alleles corresponding to only four of these nine patterns were associated with β-lactam resistance. The
mecA
alleles that did not confer β-lactam resistance were largely restricted to coagulase-negative staphylococci of animal origin, such as
S. sciuri
and
S. vitulinus
. Because of the diversity of sequences and the different impact on β-lactam susceptibility, the existence of different
mecA
alleles needs to be taken into account when designing diagnostic assays for the detection of
mecA
.
The Putative Lactococcal Extracytoplasmic Function Anti-Sigma Factor Llmg2447 Determines Resistance to the Cell Wall-Active Bacteriocin Lcn972
Authors: Roces Clara , Pérez Verónica , Campelo Ana B. , Blanco Diego , Kok Jan , Kuipers Oscar P. , Rodríguez Ana , Martínez Beatriz
Published: August 2012

Lactococcin 972 (Lcn972) is a cell wall-active bacteriocin that inhibits cell wall biosynthesis in
Lactococcus lactis
. In this work, the transcriptomes of the Lcn972-resistant (Lcn
r
) mutant
L. lactis
D1 and its parent strain were compared to identify factors involved in Lcn972 resistance. Upregulated genes included members of the cell envelope stress (CesSR) regulon, the penicillin-binding protein
pbpX
gene and gene
llmg2447
, which may encode a putative extracytoplasmic function (ECF) anti-sigma factor. The gene
llmg2447
is located downstream of the nonfunctional ECF gene

sigX
pseudo

. Nisin-controlled expression of
llmg2447
led to high Lcn972 resistance in
L. lactis
, with no cross-resistance to other cell wall-active antimicrobials. Upregulation of
llmg2447
in
L. lactis
D1 (Lcn
r
) was linked to the integration of insertion element IS
981
into the
llmg2447
promoter region, replacing the native −35 box and activating the otherwise silent promoter P

2447

. This is the first example of an orphan ECF anti-sigma factor involved in bacteriocin resistance. This new role in neutralizing cell wall-active compounds (e.g., Lcn972) could have evolved from a putative primary function of Llmg2447 in sensing cell envelope stress.
Trichinella spiralis Secreted Enzymes Regulate Nucleotide-Induced Mast Cell Activation and Release of Mouse Mast Cell Protease 1
Authors: Afferson Holly C. , Eleftheriou Emily , Selkirk Murray E. , Gounaris Kleoniki
Published: August 2012

Extracellular nucleotides are important triggers of innate immunity, acting on a wide variety of cells via signaling through purinergic receptors. Mucosal mast cells contribute to expulsion of a number of gastrointestinal nematode parasites, and mouse mast cell protease 1 has been shown to have a critical role in clearance of
Trichinella spiralis
from the intestinal tract. We show here that adenosine, ADP, ATP, UDP, and UTP all stimulate calcium mobilization in bone marrow-derived mast cells with a mucosal phenotype. Secreted proteins from
T. spiralis
infective larvae inhibit nucleotide-induced mast cell activation, and that induced by ADP and UDP is specifically blocked by parasite secretory 5′-nucleotidase. Release of mouse mast cell protease 1 is stimulated by ADP and ATP. Both parasite secreted products and the 5′-nucleotidase inhibit ADP-induced release of mast cell protease, whereas that stimulated by ATP is partially inhibited by secreted products alone. This indicates that the 5′-nucleotidase contributes to but is not solely responsible for inhibition of nucleotide-mediated effects on mast cell function. Secretion of nucleotide-metabolizing enzymes by parasitic nematodes most likely evolved as a strategy for suppression of innate immune responses and is discussed in this context.
Role of Interleukin-32 in Helicobacter pylori-Induced Gastric Inflammation
Authors: Sakitani Kosuke , Hirata Yoshihiro , Hayakawa Yoku , Serizawa Takako , Nakata Wachiko , Takahashi Ryota , Kinoshita Hiroto , Sakamoto Kei , Nakagawa Hayato , Akanuma Masao , Yoshida Haruhiko , Maeda Shin , Koike Kazuhiko
Published: August 2012

Helicobacter pyloriinfection is associated with gastritis and gastric cancer. AnH. pylorivirulence factor, thecagpathogenicity island (PAI), is related to host cell cytokine induction and gastric inflammation. Since elucidation of the mechanisms of inflammation is important for therapy, the associations between cytokines and inflammatory diseases have been investigated vigorously. Levels of interleukin-32 (IL-32), a recently described inflammatory cytokine, are increased in various inflammatory diseases, such as rheumatoid arthritis and Crohn's disease, and in malignancies, including gastric cancer. In this report, we examined IL-32 expression in human gastric disease. We also investigated the function of IL-32 in activation of the inflammatory cytokines in gastritis. IL-32 expression paralleled human gastric tissue pathology, with low IL-32 expression inH. pylori-uninfected gastric mucosa and higher expression levels in gastritis and gastric cancer tissues.H. pyloriinfection increased IL-32 expression in human gastric epithelial cell lines.H. pylori-induced IL-32 expression was dependent on the bacterialcagPAI genes and on activation of nuclear factor κB (NF-κB). IL-32 expression induced byH. pyloriwas not detected in the supernatant of AGS cells but was found in the cytosol. Expression of theH. pylori-induced cytokines CXCL1, CXCL2, and IL-8 was decreased in IL-32-knockdown AGS cell lines compared to a control AGS cell line. We also found that NF-κB activation was decreased inH. pylori-infected IL-32-knockdown cells. These results suggest that IL-32 has important functions in the regulation of cytokine expression inH. pylori-infected gastric mucosa.