bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of neuronal chloride homeostasis by neuromodulators
Authors: Mahadevan Vivek , Woodin Melanie A.
Published: February 2016

KCC2 is the central regulator of neuronal Cl− homeostasis, and is critical for enabling strong hyperpolarizing synaptic inhibition in the mature brain. KCC2 hypofunction results in decreased inhibition and increased network hyperexcitability that underlies numerous disease states including epilepsy, neuropathic pain and neuropsychiatric disorders. The current holy grail of KCC2 biology is to identify how we can rescue KCC2 hypofunction in order to restore physiological levels of synaptic inhibition and neuronal network activity. It is becoming increasingly clear that diverse cellular signals regulate KCC2 surface expression and function including neurotransmitters and neuromodulators. In the present review we explore the existing evidence that G‐protein‐coupled receptor (GPCR) signalling can regulate KCC2 activity in numerous regions of the nervous system including the hypothalamus, hippocampus and spinal cord. We present key evidence from the literature suggesting that GPCR signalling is a conserved mechanism for regulating chloride homeostasis. This evidence includes: (1) the activation of group 1 metabotropic glutamate receptors and metabotropic Zn2+ receptors strengthens GABAergic inhibition in CA3 pyramidal neurons through a regulation of KCC2; (2) activation of the 5‐hydroxytryptamine type 2A serotonin receptors upregulates KCC2 cell surface expression and function, restores endogenous inhibition in motoneurons, and reduces spasticity in rats; and (3) activation of A3A‐type adenosine receptors rescues KCC2 dysfunction and reverses allodynia in a model of neuropathic pain. We propose that GPCR‐signals are novel endogenous Cl− extrusion enhancers that may regulate KCC2 function.

image
Finite-Element Analysis of Waspaloy Using Sinh Creep-Damage Constitutive Model Under Triaxial Stress State
Authors: Haque Mohammad Shafinul , Stewart Calvin Maurice
Published: February 2016

The creep deformation and damage evolution of nickel base superalloy (Waspaloy) at 700 °C are studied using the classic Kachanov–Rabotnov (KR) and a recently developed Sin-hyperbolic (Sinh) model. Uniaxial creep deformation and Bridgman rupture data collected from literature are used to determine the model constants and to compare the KR and the Sinh solutions. Finite-element (FE) simulations on a single eight-node element are conducted to validate the accuracy of the FE code. It is observed that KR cannot predict the creep deformation, damage, and rupture life of nickel base superalloys accurately using one set of constants for all the stress levels. The Sinh model exhibits a superior ability to predict the creep behavior using one set of constants for all the stress levels. Finite-element analysis (FEA) on 3D Bridgman notched Waspaloy specimen using the Sinh model is conducted. The results show that the Sinh model when combined with a representative stress equation and calibrated with experimental data can accurately predict the “notch effect” observed in the rupture life of notched specimen. Contour plots of damage evolution and stress redistribution are presented. It is demonstrated that the Sinh model is less stress sensitive, produces unconditional critical damage equal to unity at rupture, exhibits a more realistic damage distribution around the crack tip, and offers better crack growth analysis than KR.
Computational Analysis of Effect of Circumferential Groove Casing Treatment With Different Axial Coverage Over Rotor Blade Tip Chord on the Performance of a Transonic Axial Compressor Stage
Authors: Mehta Nishit J. , Alone Dilipkumar Bhanudasji , Choksi Harish S.
Published: February 2016

Previous studies on circumferential groove casing treatments have shown that the effectiveness of casing Grooves highly depends on their axial location over blade tip. The present work aims to study the flow behavior and its impact on the performance of the compressor stage when the casing treatment grooves are placed to provide different axial coverage over rotor chord in each case. Geometry of a transonic compressor stage was modeled for this study. Flow field solutions for this model with smooth casing wall were obtained by solving steady state 3-D Reynolds-Averaged Navier-Stokes equations for three different grids to prove the grid independence of the solutions. Results obtained with the intermediate grid density were used as the baseline results to compare with results of casing treatment geometries. The basic casing treatment geometry has 10 circumferential groves of width 4mm, depth 16mm and axial spacing of 2mm between each groove. This casing treatment geometry was superimposed over the rotor domain with the grooves extending axially over the entire axial chord (58mm) of rotor blade tip and flow field solutions were again obtained. After that, for each case the grooves are removed from the rear side and axial coverage is shortened. Flow solutions for various axial coverage and hence for various number of grooves are thus obtained and compared. These results depict improvement in the operating range when compared to the Base-line results. Results also exhibit that as the grooves from the rear end are removed gradually, recovery in the overall efficiency is seen in compressor performance. Post processing of the flow solutions confirms the trend and shows that the grooves in the rear of the chord are almost idle not providing sufficient flow to pass over from pressure surface to suction surface of the blade and hence contributing very less towards performance enhancement.
Flame Investigation of a Gas Turbine Central Pilot Body Burner at Atmospheric Pressure Conditions Using OH PLIF and High-Speed Flame Chemiluminescence Imaging
Authors: Subash Arman Ahamed , Whiddon Ronald , Collin Robert , Aldén Marcus , Kundu Atanu , Klingmann Jens
Published: February 2016

Experiments were performed on the central pilot body (RPL-rich-pilot-lean) of Siemens prototype 4th generation DLE burner to investigate the flame behavior at atmospheric pressure condition when varying equivalence ratio, residence time and co-flow temperature. The flame at the RPL burner exit was investigated applying OH planar laser-induced fluorescence (PLIF) and high-speed chemiluminescence imaging. The results from chemiluminescence imaging and OH PLIF show that the size and shape of the flame are clearly affected by the variation in operating conditions. For both preheated and non-preheated co-flow cases, at lean equivalence ratios combustion starts early inside the burner and primary combustion comes to near completion inside the burner if residence time permits. For rich conditions, the unburnt fuel escapes out through the burner exit along with primary combustion products and combustion subsequently restarts downstream the burner at leaner condition and in a diffuse-like manner. For preheated co-flow, most of the operating conditions yield similar OH PLIF distributions and the flame is stabilizing at approximately the same spatial positions. It reveals the importance of the preheating co-flow for flame stabilization. Flame instabilities were observed and Proper Orthogonal Decomposition (POD) is applied to time resolved chemiluminescence data to demonstrate how the flame is oscillating. Preheating has strong influence on the oscillation frequency. Additionally, combustion emissions were analyzed to observe the effect on NOX level for variation in operating conditions.
CFD Wind Tunnel Tests of Centrifugal Stage Return Channel Vane Cascades
Authors: Galerkin Y. , Marenina L. , Soldatova K.
Published: February 2016

Stator part of a centrifugal compressor stage is a proper object of study by CFD calculations meaning better understanding of flow behavior, checking of field type design methods and possible improvements. Several stators with vane and vaneless diffusers for stages with different specific speed were designed by standard methodology and numerically analyzed. Results were verified. Calculation in a whole has demonstrated validity of existing recommendation. The specific velocity for stators is introduced which can be applied to match an impeller and a stator. Calculations demonstrated quick efficiency drop for stators with specific speed less than 0,215. Return channel vane cascades were studied in wide range of solidity with constant vane height and with constant radial component of velocity. Empirical formulae with non-dimensional circulation as an argument are proposed for loss coefficient, profile loss coefficient, optimal incidence angle and exit lag angle. Candidates of the low specific speed stator have demonstrated that an arbitrary channels’ wideness to diminish friction losses is not effective. Better flow organization is preferable. Modification of a crossover demonstrated positive results for high and low specific speed stators.
Multi-Parametric Model Predictive Control Strategy on Laboratory SR-30 Gas Turbine
Authors: Surendran Swathi , Chandrawanshi Ritesh , Kulkarni Sanjeet , Bhartiya Sharad , Nataraj Paluri S. V. , Sampath Suresh
Published: February 2016

This paper deals with the development of multi-parametric Model Predictive Control (mp-MPC) strategies for a laboratory SR-30 gas turbine setup. The objective is to control the engine speed and turbine exhaust pressure of the gas turbine. Firstly, an empirical transfer function model is obtained experimentally, between the fuel flow-shaft speed and nozzle diameter-turbine exhaust pressure (TEP) of the gas turbine. Then, Model Predictive Control (MPC) is designed based on the empirical models. The output responses under MPC are found to be satisfactory, however, with large computational time. Next, mp-MPC controllers are designed based on the empirical models. Relevant operating constraints are also added as design specifications. It is found that the multi-parametric MPC delivers superior results in comparison with conventional MPC, in terms of computational time, while delivering the same transient performance.
Non-Linear Transient Stability Analysis of a Rigid Rotor Supported on Journal Bearings With Rectangular Dimples
Authors: Turaga Ram
Published: February 2016

The influence of deterministic surface texture on the sub-synchronous whirl stability of a rigid rotor has been studied. Non-linear transient stability analysis has been performed to study the stability of a rigid rotor supported on two symmetric journal bearings with a rectangular dimple of large aspect ratio. The surface texture parameters considered are dimple depth to minimum film thickness ratio and the location of the dimple on the bearing surface. Journal bearings of different Length to diameter ratios have been studied. The governing Reynolds equation for finite journal bearings with incompressible fluid has been solved using the Finite Element Method under isothermal conditions. The trajectories of the journal center have been obtained by solving the equations of motion of the journal center by the fourth-order Runge-Kutta method. When the dimple is located in the raising part of the pressure curve the positive rectangular dimple is seen to decrease the stability whereas the negative rectangular dimple is seen to improve the stability of the rigid rotor.
Numerical Investigation on Tandem Compressor Cascades
Authors: Madasseri Payyappalli Manas , Shine S. R.
Published: February 2016

Tandem blade arrangement of axial compressors has been proposed to obtain high loading and turning compared to a single blade. The objectives of the current study is to investigate the effect of percent pitch, axial overlap and incidence angle for a low speed axial compressor stator cascade and to supplement the results with the flow structures observed. 2-D numerical study was conducted using a finite volume scheme which solves the RANS equations along with the Spalart-Allmaras turbulence model. Comparison offlow structures corresponding to different percent pitch, axial overlap and incidence angle has been made to highlight all prominent flow mechanisms. It is observed that the flow through the gap nozzle between the two blades has significant effects on losses. The incidence range of the tandem cascades is found to be superior to the corresponding single blade cases.
Ultimate Load Capacities of Bolted Flanges
Authors: Kotur Raghavan , Kasina Lakshman
Published: February 2016

In great majority of situations, bolted flanges are designed to work well within elastic limits. The main design considerations concern preload which should be high enough to limit fatigue loading of the bolt and also prevent flange opening in the operating range. Elastic design of bolted joints as well their finite element simulation have been well understood.

The present paper deals with post elastic behavior of bolted joints. Equipment and structures are often exposed to loads much higher than the normal operating loads. Civil engineering structures experiencing earthquakes is one such example. Military ships and submarines are subject to torpedo loads and other types of blast loads. Aircraft engines are subject to ultimate load conditions such as fan blade-off (FBO) and foreign object damage (FOD) like bird-hit. To meet such eventualities it is uneconomical to attempt elastic designs. The approach is to go for plastic designs. The criterion is that the structure or equipment can yield and distort but should not rupture. The philosophy is that the distorted parts are replaced once the event is over. Bolted joints are invariably present in these categories of equipment.

The present paper deals with simulation and structural behavior of components fastened together by way of threaded fasteners. Sector of bolted flange is considered for study and elastic-plastic analyses are carried out. This is an extension of the work carried out earlier by the authors for simple axisymmetric joints. The earlier study was for conceptual understanding. In the present study focus will be on design aspects. Three different simulation models are compared. In addition, parametric studies are conducted to get deeper insight into structural behavior.
Enhancement of Wind Turbine Aerodynamic Performance Using New Designed Airfoils
Authors: Kedam Naresh , Nakka Sudhakar , Baloni Beena D. , Channiwala S. A.
Published: February 2016

The rotor is the first element in the chain of functional elements of a wind turbine. Therefore, its aerodynamic and dynamic properties have a decisive influence on the entire system in many respects. The capability of the rotor to convert a maximum proportion to the wind energy, flowing through its swept area, into mechanical energy is obviously the direct result of its aerodynamic properties. These will determine the overall efficiency of the energy conversion in the wind turbine. To enhance the performance of wind turbine, one has to analyze the effects of variations in nomenclature of a rotor blade on the performance of wind turbine.

The present paper incorporates the analysis of primary selected blade design by the Solar Energy Research Institute (SERI -8) with BEMT based simulations; five different suggested models of the rotor blade are also analyzed with same BEM based simulations, including Tip losses, 3-D corrections and Reynolds number drag correction. These six models incorporate twist optimization, chord distribution optimization, and the combination of airfoils, new designed airfoils and base model SERI-8 rotor blade. Without modifying the size of the rotor blade, different analysis is done and improved the rotor aerodynamics efficiency. Highly aerodynamics efficient new designed airfoils produce more lift and minimize the drag by avoiding the stall; it develops high-value of coefficient of lift to drag (Cl/Cd) ratio. The rated power for all models considered at 15m/s for analysis. The result suggests that the rotor power efficiency is 25.772% with SERI-8, 29.420% with the twist optimized model, 55.51% with the model with a combination of SG series and SERI series airfoils and 61.62% with new designed airfoils (SV Series) model. Respectively, efficiency is increased by 3.64%, 29.745%, and 35.84% compared to SERI-8 blade.
Suppression of Combustion Noise in Gas Turbine Combustors
Authors: Kumar Juvva Srihari Dinesh , Mariappan Sathesh , Kushari Abhijit
Published: February 2016

This study deals with the investigations on the sources and the control of combustion noise, in an atmospheric gas turbine combustor. Combustion noise encountered here is also termed as hooting, as it occurs within a limited bandwidth of frequencies ranging from 300–450 Hz. Combustion noise is usually classified as direct and in-direct combustion noise. The present study emphases on the direct combustion noise which occurs when a volume of gas expands at constant pressure, as soon as it is heated by combustion; this results in a sound wave which propagates outside the boundary of the flame. At certain conditions, if the unsteady heat release rate drives the acoustic oscillations, satisfying Rayleigh criterion, pressure oscillations grow leading to discrete tonal sound and this phenomena is termed as combustion instability.

Experiments are conducted in a liquid fuelled swirl stabilized atmospheric gas turbine combustor, whose aspect ratio is 2.5, combustion intensity varies from 25MW/m3 atm to 50MW/m3 atm. Air is passed through various stages: primary, secondary, quenching and atomizing air. Aviation turbine fuel is injected through an air-blast atomizer. An unsteady pressure transducer is located at the primary zone to measure the acoustic oscillations. The frequency of sound generated during the combustion process is compared with a microphone located at 1.25 m away from the combustor at an angle of 45° from the axis of the combustor.

The main objective of this paper is to investigate the cause of hooting and the passive control techniques in order to reduce it. This is achieved by two ways, systematically by two ways, i) reducing the quenching air methodologically reducing the quenching air and ii) varying the air to liquid (fuel) ratio (ALR). By imparting these methods the sound pressure level inside the combustor is reduced from 143dB to 128dB. Since, combustion noise occurs in a broad-band of frequencies, the unsteady data obtained with the pressure transducer are analyzed using octave bands, where it shows linear decrement of energy present in-between the two frequencies. In order to perform parametric study, two swirlers of swirl numbers.0.77 and 0.86 are used. Established by the physics of Helmholtz oscillator, the combustor hooting is dictated, by which the sound produced by the combustor is explained.
Primary Breakup of Liquid Jet in an Annular Passage in Crossflow of Air
Authors: Kumar Deepak , Kushari Abhijit , Lovett Jeffery A. , Syed Saadat
Published: February 2016

This paper presents an experimental study of primary breakup of liquid jet in an annular passage in a cross flow of air at a fixed Mach number of 0.12, at atmospheric pressures. The experiments were conducted for various velocities of liquid jet from 1.417 m/s to 7.084 m/s (based on orifice diameter = 1 mm) and the corresponding liquid-air momentum flux ratios varied from 1 to 25. The droplet sizes and velocities were measured using a Phase Doppler Particle Analyzer (PDPA) downstream of the liquid inlet port along the axial direction at the centerline of the annular passage along the plane of injection. Observed droplet sizes and velocity variations at different momentum flux ratios, in the axial direction, show three distinct zones. The first zone is the ligament formation zone represented by large variation in droplet Reynolds number with momentum ratio. The second zone is the primary droplet formation zone in which a fairly monotonic decrease in droplet size and droplet acceleration due to the breakup is observed. However, the Reynolds number of the droplets is almost invariant with momentum ratio. The third zone is where the spray attains the critical state where the size and velocity does not vary in the axial direction and the variation in size in this zone with the momentum ratio is primarily due to the initial conditions established in the ligament formation zone.
Model Order Reduction of Visco-Thermal Acousto-Elastic Interaction in High-Pressure Centrifugal Compressors
Authors: Jith Jithin , Sarkar Sunetra
Published: February 2016

Centrifugal compressors used in applications like enhanced oil recovery using gas re-injection and Carbon capture and sequestration operate at very high pressures and often have to to deal with supercritical CO2 which is considerably viscous. Increased viscosity leads to energy dissipation and introduces damping in the acousto-elastic interaction between supercritical CO2 and the impeller of a centrifugal compressor, thereby altering the frequency response of the system especially near resonant frequencies. In this paper, the damping introduced by visco-thermal effects in such acousto-elastic systems is accounted for in a numerically efficient manner.

The acoustics in the fluid are modelled using the Boundary Layer Impedance (BLI) model and the centrifugal impeller as a linear elastic structure. The coupled acousto-elastic system is then solved using the finite element method. The finite element solution becomes computationally expensive especially when working with large three-dimensional models. In order to reduce the computational cost, a model order reduction technique based on a multi-point second-order Arnoldi (SOAR) procedure is developed. It is demonstrated that the reduced order model significantly brings down the computational time while being sufficiently accurate.
Instabilities Investigation in Wet Gas Compressor by Flow Visualisation
Authors: Ferrara Veronica , Bakken Lars E.
Published: February 2016

Since the production of oil and gas is declining, the development and implementation of new, cost-efficient technology is an important focus area in order to enhance production and recovery from existing fields. The wet gas compressor represents a key element because it has been identified as one of the most relevant technologies to be developed.

In recent years, research on subsea installations has been carried out. A traditional centrifugal compressor may not be applicable to handle liquid during a standard process. A complete comprehension of the machine behaviour, in particular investigation with the presence of gas-liquid mixture is essential. Because of liquid impact, compressor performances and consequently the margin of stability might be modified. Delayed instability inception should also be pointed out.

The objective of this paper is to provide a consistent basis for the surge and rotating stall analysis of wet gas compressors and describe the mechanism leading to instabilities and their evolution. Visualisation of flow in the compressor stage is accomplished by means of fluorescent injection in correspondence with the impeller labyrinth seal and diffuser section. Simultaneously, a fast Fourier transform examination is realised in order to identify characteristic frequencies of unsteady events.
Experimental Investigation on Performance of Pulsating Heat Pipe
Authors: Hari Prasad Tarigonda , Kukutla Pol Reddy , Mallikarjuna Rao P. , Reddy R. Meenakshi
Published: February 2016

Pulsating heat pipes (PHP) receives heat from the working fluid distributes itself naturally in the form of liquid–vapor system, i.e., receiving heat from one end and transferring it to other end by a pulsating action of the liquid–vapor system. Pulsating heat pipes have more advantages than other heat pipes. The problem identified is, to calculate the performance of the pulsating heat pipes with respect to different inclinations using various parameters. In this paper, experiment on performance of closed single loop pulsating heat pipe (CLPHP) using water as a working fluid is considered. The parameters such as thermal resistance (Rth), heat transfer coefficient (h), and variation of temperature with respect to time for the given input at different inclinations such as 0°, 45°, and 90° are taken for the present work. Water is used as the working fluid and is subjected to 50% filling ratio and vacuumed at a pressure of 2300Pa. The performance is calculated at different inclinations of the CLPHP with single turn/loop. The factors such as heat transfer coefficient, thermal resistance, time taken for heating the pulsating heat pipe with the given input are calculated. Finally, it has been concluded that is preferable orientation for PHP and it was found be at vertical orientation i.e., at 90° inclination, because more pulsating action is taken place at this inclination and henceforth, heat transfer rate is faster at this inclination.
CFD Analysis of Effect of Diffuser Vane Setting Angle and Shape on the Performance of a Centrifugal Compressor Stage
Authors: Pothuri Venkateswara Rao , Govindaraju Ramana Murty , Ganapathiraju Venkata Rao , Palati Naga Vamsi , Badisa Sivaram
Published: February 2016

This paper describes the computational results on the performance of a centrifugal compressor stage with Vaneless diffuser (VLD) and low solidity vaned diffuser (LSVD) by varying blade shape and its setting angle. The centrifugal compressor stage configuration consists of a 2-D impeller with a diffuser. Analysis was conducted for VLD and four different blade shapes of LSVD namely Un-cambered constant thickness flat plate (FP), Cambered curved arc constant thickness plate (CCAP), Un-cambered aerofoil profile NACA 0010(NACA 0010) and Cambered aerofoil profile NACA 2410 (NACA 2410) at five different setting angles ranging from 16° to 32° in steps of 4° for each blade. The study is conducted at five different flow coefficients, at 0.8, 0.9, 1.0, 1.1 and 1.2 of design mass flow rate representing the design and off design cases for VLD and LSVD. CFD results are validated with experimental results for stages with VLD and LSVD for certain chosen performance parameters such as head coefficient, stage input power and exit flow angle. The computational results indicate that variations in diffuser vane geometry and its setting angle causes changes in all significant performance parameters like the total head coefficient, total-to-static stage efficiency, power coefficient of the stage and static pressure recovery coefficient of the diffuser. Contour plots were generated from CFD results and analyzed for better understanding of effect of diffuser vane shape and its setting angle on the performance of the centrifugal compressor. As a result of this study, it can be concluded that the centrifugal compressor shows improved performance characteristics for chosen blade shape of low solidity vaned diffuser than VLD.
Data sharing
Authors: McNutt Marcia
Published: February 2016

The
Science
family of journals is committed to sharing data relevant to public health emergencies, and therefore we are signatories to, and wholeheartedly endorse, the following statement by funders and journals.
*
Are Accurins the cure for Aurora kinase inhibitors?
Authors: Bearss David J.
Published: February 2016

A nanoparticle formulation of an Aurora B inhibitor increases antitumor efficacy and reduces toxicity, which may be a precedent for the use of this technology with other small molecules (Ashton
et al
., this issue).
Toll-Like Receptor Activation by Generalized Modules for Membrane Antigens from Lipid A Mutants of Salmonella enterica Serovars Typhimurium and Enteritidis
Authors: Rossi Omar , Caboni Mariaelena , Negrea Aurel , Necchi Francesca , Alfini Renzo , Micoli Francesca , Saul Allan , MacLennan Calman A. , Rondini Simona , Gerke Christiane
Published: February 2016

Invasive nontyphoidal
Salmonella
(iNTS) disease is a neglected disease with high mortality in children and HIV-positive individuals in sub-Saharan Africa, caused primarily by Africa-specific strains of
Salmonella enterica
serovars Typhimurium and Enteritidis. A vaccine using GMMA (generalized modules for membrane antigens) from
S.
Typhimurium and
S.
Enteritidis containing lipid A modifications to reduce potential
in vivo
reactogenicity is under development. GMMA with penta-acylated lipid A showed the greatest reduction in the level of cytokine release from human peripheral blood monocytes from that for GMMA with wild-type lipid A. Deletion of the lipid A modification genes
msbB
and
pagP
was required to achieve pure penta-acylation. Interestingly, Δ
msbB
Δ
pagP
GMMA from
S.
Enteritidis had a slightly higher stimulatory potential than those from
S.
Typhimurium, a finding consistent with the higher lipopolysaccharide (LPS) content and Toll-like receptor 2 (TLR2) stimulatory potential of the former. Also, TLR5 ligand flagellin was found in
Salmonella
GMMA. No relevant contribution to the stimulatory potential of GMMA was detected even when the flagellin protein FliC from
S.
Typhimurium was added at a concentration as high as 10% of total protein, suggesting that flagellin impurities are not a major factor for GMMA-mediated immune stimulation. Overall, the stimulatory potential of
S.
Typhimurium and
S.
Enteritidis Δ
msbB
Δ
pagP
GMMA was close to that of
Shigella
sonnei
GMMA, which are currently in phase I clinical trials.
Hepatitis C Virus-Induced Degradation of Cell Death-Inducing DFFA-Like Effector B Leads to Hepatic Lipid Dysregulation
Authors: Lee Emily M. , Alsagheir Ali , Wu Xianfang , Hammack Christy , McLauchlan John , Watanabe Noriyuki , Wakita Takaji , Kneteman Norman M. , Douglas Donna N. , Tang Hengli
Published: February 2016

Individuals chronically infected with hepatitis C virus (HCV) commonly exhibit hepatic intracellular lipid accumulation, termed steatosis. HCV infection perturbs host lipid metabolism through both cellular and virus-induced mechanisms, with the viral core protein playing an important role in steatosis development. We have recently identified a liver protein, the cell death-inducing DFFA-like effector B (CIDEB), as an HCV entry host dependence factor that is downregulated by HCV infection in a cell culture model. In this study, we investigated the biological significance and molecular mechanism of this downregulation. HCV infection in a mouse model downregulated CIDEB in the liver tissue, and knockout of the CIDEB gene in a hepatoma cell line results in multiple aspects of lipid dysregulation that can contribute to hepatic steatosis, including reduced triglyceride secretion, lower lipidation of very-low-density lipoproteins, and increased lipid droplet (LD) stability. The potential link between CIDEB downregulation and steatosis is further supported by the requirement of the HCV core and its LD localization for CIDEB downregulation, which utilize a proteolytic cleavage event that is independent of the cellular proteasomal degradation of CIDEB.

IMPORTANCE
Our data demonstrate that HCV infection of human hepatocytes
in vitro
and
in vivo
results in CIDEB downregulation via a proteolytic cleavage event. Reduction of CIDEB protein levels by HCV or gene editing, in turn, leads to multiple aspects of lipid dysregulation, including LD stabilization. Consequently, CIDEB downregulation may contribute to HCV-induced hepatic steatosis.
Traumatic brain injury and the evidence for its management
Authors: Lewis Jason Robert
Published: February 2016

A 29-year-old man presented to a major trauma centre with traumatic brain injury. Following cranial decompression, the patient was admitted to the intensive care unit for medical management and monitoring. This case report reviews the evidence for the management of traumatic brain injury.
Spontaneous lymphocoele: an unusual cause of an axillary mass
Authors: Copley Phillip Correia , Ali Liaqat , Mirza Shaukat
Published: February 2016

A lymphocoele or cystic hygroma is a benign lymphatic malformation that usually presents as a congenital mass in infancy. These masses are most common in the cervicofacial region and more rarely occur elsewhere in the body. Spontaneous, atraumatic presentation in adulthood is extremely rare. We present a case of a 59-year-old woman who presented with a fluctuant mass in the axilla, which was diagnosed as a lymphocoele. Initial management by ultrasound-guided aspiration of the cyst proved unsuccessful due to recurrence. Surgical excision of the cyst was then successfully performed and histological analysis proved the diagnosis. The incidence of adult-onset lymphocoele without a history of prior trauma or operation is rare. This case report adds to the literature and reviews the various management strategies that have been successfully employed.
Dysphagia and aspiration as the only manifestations of a stroke
Authors: García Carretero Rafael , Romero Brugera Marta , Rebollo-Aparicio Noelia , Rodeles-Melero Javier
Published: February 2016

A 56-year-old patient was admitted to our hospital, presenting with dysphagia as the only symptom. He was very concerned about this difficulty in swallowing. Diseases of the upper digestive tract were suspected, but further investigations revealed a neurological disorder. He had suffered a brain stem stroke and, as a consequence, developed an aspiration pneumonia. What seemed a digestive disorder was indeed a brain stem stroke, therefore we had to deal with the diverse impacts of this condition.
Severe rhinovirus pneumonia in a young woman taking performance-enhancing drugs
Authors: Mayer Kristina Nadine , Wyder Daniel , Spasic Danijela , Herren Thomas
Published: February 2016

A 22-year-old woman presented to the emergency room of a local hospital with pleuritic chest pain. She regularly worked out and admitted to taking performance-enhancing drugs (PEDs). Clinical findings and further diagnostic work up revealed a diagnosis of perimyocarditis, and adequate therapy was initiated. During the course of the first day, the patient had to be intubated and mechanically ventilated. A diagnosis of bilateral pneumonia and acute respiratory distress syndrome (ARDS) due to an infection by rhinovirus spp was made. A smoking habit, the intense physical training and the use of PED's may have exacerbated the course of the viral pneumonia. After 12 days the patient could be extubated. The length of stay in the intensive care unit was 16 days. After hospital discharge, the patient went to a pulmonary rehabilitation facility for 2 weeks. The outcome was favourable and the patient resumed her strength and endurance training.
Does Lean healthcare improve patient satisfaction? A mixed-method investigation into primary care
Authors: Poksinska Bozena Bonnie , Fialkowska-Filipek Malgorzata , Engström Jon
Published: February 2016

Background

Lean healthcare is claimed to contribute to improved patient satisfaction, but there is limited evidence to support this notion. This study investigates how primary-care centres working with Lean define and improve value from the patient's perspective, and how the application of Lean healthcare influences patient satisfaction.

Methods

This paper contains two qualitative case studies and a quantitative study based on results from the Swedish National Patient Survey. Through the case studies, we investigated how primary-care organisations realised the principle of defining and improving value from the patient's perspective. In the quantitative study, we compared results from the patient satisfaction survey for 23 primary-care centres working with Lean with a control group of 23 care centres not working with Lean. We also analysed changes in patient satisfaction over time.

Results

Our case studies reveal that Lean healthcare implementations primarily target efficiency and little attention is paid to the patient's perspective. The quantitative study shows no significantly better results in patient satisfaction for primary-care centres working with Lean healthcare compared with those not working with Lean. Further, care centres working with Lean show no significant improvements in patient satisfaction over time.

Conclusions

Lean healthcare implementations seem to have a limited impact on improving patient satisfaction. Care providers need to pay more attention to integrating the patient's perspective in the application of Lean healthcare. Value needs to be defined and value streams need to be improved based on both the knowledge and clinical expertise of care providers, and the preferences and needs of patients.
Implantation of healthy matrix-embedded endothelial cells rescues dysfunctional endothelium and ischaemic tissue in liver engraftment
Authors: Melgar-Lesmes Pedro , Balcells Mercedes , Edelman Elazer R
Published: February 2016

Objective

Liver transplantation is limited by ischaemic injury which promotes endothelial cell and hepatocyte dysfunction and eventually organ failure. We sought to understand how endothelial state determines liver recovery after hepatectomy and engraftment.

Design

Matrix-embedded endothelial cells (MEECs) with retained healthy phenotype or control acellular matrices were implanted in direct contact with the remaining median lobe of donor mice undergoing partial hepatectomy (70%), or in the interface between the remaining median lobe and an autograft or isograft from the left lobe in hepatectomised recipient mice. Hepatic vascular architecture, DNA fragmentation and apoptosis in the median lobe and grafts, serum markers of liver damage and phenotype of macrophage and lymphocyte subsets in the liver after engraftment were analysed 7 days post-op.

Results

Healthy MEECs create a functional vascular splice in donor and recipient liver after 70% hepatectomy in mouse protecting these livers from ischaemic injury, hepatic congestion and inflammation. Macrophages recruited adjacent to the vascular nodes into the implants switched to an anti-inflammatory and regenerative profile M2. MEECs improved liver function and the rate of liver regeneration and prevented apoptosis in donor liver lobes, autologous grafts and syngeneic engraftment.

Conclusions

Implants with healthy endothelial cells rescue liver donor and recipient endothelium and parenchyma from ischaemic injury after major hepatectomy and engraftment. This study highlights endothelial-hepatocyte crosstalk in hepatic repair and provides a promising new approach to improve regenerative medicine outcomes and liver transplantation.
Angiogenesis in melanoma: an update with a focus on current targeted therapies
Authors: Jour George , Ivan Doina , Aung Phyu P
Published: February 2016

Angiogenesis plays a crucial role in melanoma metastasis and progression. In recent years, numerous studies have investigated the prognostic and clinical significance of this phenomenon, and the development of molecular techniques has enabled us to achieve a better understanding of angiogenesis in melanoma. Herein, we review the current state of knowledge regarding angiogenesis in melanoma, including the pathophysiological, histological and immunohistochemical aspects of this phenomenon. We also review the molecular pathways involved in angiogenesis and the interplay between different components that might be manipulated in the future development of efficient targeted therapies. Recently developed targeted antiangiogenic therapies in clinical trials and included in the treatment of advanced-stage melanoma are also reviewed.
Immunisation coverage in rural–urban migrant children in low and middle-income countries (LMICs): a systematic review and meta-analysis
Authors: Awoh Abiyemi Benita , Plugge Emma
Published: February 2016

Background

The majority of children who die from vaccine-preventable diseases (VPDs) live in low-income and-middle-income countries (LMICs). With the rapid urbanisation and rural–urban migration ongoing in LMICs, available research suggests that migration status might be a determinant of immunisation coverage in LMICs, with rural–urban migrant (RUM) children being less likely to be immunised.

Objectives

To examine and synthesise the data on immunisation coverage in RUM children in LMICs and to compare coverage in these children with non-migrant children.

Methods

A multiple database search of published and unpublished literature on immunisation coverage for the routine Expanded Programme on Immunisation (EPI) vaccines in RUM children aged 5 years and below was conducted. Following a staged exclusion process, studies that met the inclusion criteria were assessed for quality and data extracted for meta-analysis.

Results

Eleven studies from three countries (China, India and Nigeria) were included in the review. There was substantial statistical heterogeneity between the studies, thus no summary estimate was reported for the meta-analysis. Data synthesis from the studies showed that the proportion of fully immunised RUM children was lower than the WHO bench-mark of 90% at the national level. RUMs were also less likely to be fully immunised than the urban-non-migrants and general population. For the individual EPI vaccines, all but two studies showed lower immunisation coverage in RUMs compared with the general population using national coverage estimates.

Conclusions

This review indicates that there is an association between rural–urban migration and immunisation coverage in LMICs with RUMs being less likely to be fully immunised than the urban non-migrants and the general population. Specific efforts to improve immunisation coverage in this subpopulation of urban residents will not only reduce morbidity and mortality from VPDs in migrants but will also reduce health inequity and the risk of infectious disease outbreaks in wider society.
Ebola, jobs and economic activity in Liberia
Authors: Bowles Jeremy , Hjort Jonas , Melvin Timothy , Werker Eric
Published: February 2016

Background

The 2014 Ebola virus disease (EVD) outbreak in the neighbouring West African countries of Guinea, Liberia and Sierra Leone represents the most significant setback to the region's development in over a decade. This study provides evidence on the extent to which economic activity declined and jobs disappeared in Liberia during the outbreak.

Methods

To estimate how the level of activity and number of jobs in a given set of firms changed during the outbreak, we use a unique panel data set of registered firms surveyed by the business-development non-profit organisation, Building Markets. We also compare the change in economic activity during the outbreak, across regions of the country that had more versus fewer Ebola cases in a difference-in-differences approach.

Findings

We find a large decrease in economic activity and jobs in all of Liberia during the Ebola outbreak, and an especially large decline in Monrovia. Outside of Monrovia, the restaurants, and food and beverages sectors have suffered the most among the surveyed sectors, and in Monrovia, the construction and restaurant sectors have shed the most employees, while the food and beverages sectors experienced the largest drop in new contracts. We find little association between the incidence of Ebola cases and declines in economic activity outside of Monrovia.

Conclusions

If the large decline in economic activity that occurred during the Ebola outbreak persists, a focus on economic recovery may need to be added to the efforts to rebuild and support the healthcare system in order for Liberia to regain its footing.
The impact of childhood residential mobility on mental health outcomes in adolescence and early adulthood: a record linkage study
Authors: Tseliou Foteini , Maguire Aideen , Donnelly Michael , O'Reilly Dermot
Published: February 2016

Background

Understanding the causes of poor mental health in early childhood and adolescence is important as this can be a significant determinant of mental well-being in later years. One potential and relatively unexplored factor is residential mobility in formative years. Previous studies have been relatively small and potentially limited due to methodological issues. The main aim of this study was to investigate the relationship between early residential instability and poor mental health among adolescents and young adults in Northern Ireland.

Methods

A Census-based record linkage study of 28% of children aged 0–8 years in 2001 in Northern Ireland (n=49 762) was conducted, with six monthly address change assessments from health registration data and self-reported mental health status from the 2011 Census. Logistic regression models were built adjusting for socioeconomic status (SES), household composition and marital dissolution.

Results

There was a graded relationship between the number of address changes and mental ill-health (adjusted OR 3.67, 95% CIs 2.11 to 6.39 for 5 or more moves). This relationship was not modified by SES or household composition. Marital dissolution was associated with poor mental health but did not modify the relationship between address change and mental health (p=0.206). There was some indication that movement after the age of five was associated with an increased likelihood of poor mental health.

Conclusions

This large study clearly confirms the close relationship between address change in early years and later poor mental health. Residential mobility may be a useful marker for children at risk of poorer mental health in adolescence and early adulthood.
Association between personality traits and future choice of specialisation among Swedish doctors: a cross-sectional study
Authors: Bexelius Tomas S , Olsson Caroline , Järnbert-Pettersson Hans , Parmskog Malin , Ponzer Sari , Dahlin Marie
Published: February 2016

Background

Medical students' choice of their future specialty is influenced by several factors, including working conditions and type of patient relations. The aim of this study was to investigate the association between the choice of specialty and personality traits.

Methods

This is a cross-sectional questionnaire-based study of 399 alumni from Karolinska Institutet Medical School who were assumed to undergo specialty training at the time of the survey in 2013. The Big Five Inventory was used to assess the personality traits extraversion, agreeableness, conscientiousness, neuroticism and openness to experience. Medical specialties were categorised as primary care, psychiatry, internal medicine and surgical and hospital service specialties. Adjustments were made for demographic factors and the method of selection for medical school admission.

Results

The response rate was 72% (n=289, of which 262 were in training to become specialists). Among these, surgeons scored lower in agreeableness than physicians in primary care, internal medicine and hospital services. Psychiatrists and hospital service physicians showed lower conscientiousness compared with surgeons.

Conclusions

We found distinctive differences in personality traits between medical specialties even after adjusting for other potential explanatory variables. Since there are differences between specialties, for example, surgeons and psychiatrists, this supports previous findings that personality may affect medical students' specialty choice also in a Swedish setting.
Absence of circulation of Pestivirus between wild and domestic ruminants in southern Spain
Authors: Paniagua J. , García‐Bocanegra I. , Arenas‐Montes A. , Berriatua E. , Espunyes J. , Carbonero A. , Rosell R. , Marco I. , Cabezón O.
Published: February 2016

Ruminant pestiviruses (family Flaviviridae) affect both wild and domestic ruminants worldwide, causing reproductive disorders and severe economic losses. Wild (n=1442) and domestic (n=373) ruminants from southern Spain were tested for the presence of antibodies to pestiviruses. Seropositivity was detected by both ELISA and virus neutralisation test in 1/892 (0.1 per cent) red deer, 29/125 (23.2 per cent) cattle and 17/157 (10.8 per cent) sheep. Pestivirus‐specific antibodies to bovine viral diarrhoea virus (BVDV) and border disease virus (BDV) genotypes 1, 4 and 5 were detected. Significantly higher antibody titres to BDV‐4 compared with BVDV‐NADL were found in one cattle farm. Results indicate that wild ruminants may act as spillover hosts from domestic ruminants, and therefore they do not represent a risk for domestic ruminants in southern Spain. The wide distribution of pestiviruses among sheep and cattle suggests that transmission between these species may occur.