bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced Natural Circulation Modeling in the GNF BWR Core Simulator AETNA02 for ESBWR
Authors: Iwamoto Tatsuya , Miranda Dana , Banfield James , Yang Jake , Hizoum Belgacem
Published: October 2016

GE Hitachi Nuclear Energy’s (GEH) next evolution of Boiling Water Reactor (BWR) technology is the Economic Simplified Boiling Water Reactor (ESBWR). The ESBWR is a natural circulation reactor which employs numerous passive safety features while simultaneously offering a large power output for a relatively small plant footprint. The ESBWR is characterized with shortened fuel length and a tall, partitioned chimney region above the core to promote natural circulation core flow. The ESBWR is studied with Global Nuclear Fuel (GNF)’s advanced core-simulator AETNA02.

AETNA02 is a static, three-dimensional coupled nuclear-thermal hydraulic computer program representing a BWR core. The new GNF lattice-physics core simulator package LANCR02/AETNA02 consists of the two-dimensional method of characteristics based lattice code, LANCR02, which generates cross sections over a range of plant conditions and passes them to the three neutron energy group coarse mesh nodal diffusion code AETNA02. For the thermal hydraulic solution, AETNA02 includes a model which explicitly solves for the flow in each channel, water rod, and bypass region which accompanies a fuel channel. For the solution of a natural circulation plant like the ESBWR, AETNA02 utilizes the Automatic Plant Thermal Hydraulics (APTH) model which includes models for the core, the chimney region, the separator, the dryer, and the downcomer. AETNA02 iterates on the fuel channel flow and the pressure drop by modeling each chimney partition explicitly with fuel channels and bypasses mapped to it in addition to a bypass mixing model for the chimneys. This is relevant because the peripheral channels (low power) will have a lower void fraction while the central channels (higher power) will have a higher void fraction. Thus, the chimneys connected to these channels will each have a different hydrostatic head.

To verify and validate each of the APTH component models, code-to-code comparisons are performed with the GEH TRACG04 code as well as data comparisons with experiments. The TRACG04 computer program is a best-estimate two-fluid transient code. Code-to-code comparisons of the two different methods (two-fluid model in TRACG04 versus drift flux model in AETNA02) are made. In addition, this study attempts to quantify the impact on the core flow distribution that will affect the calculated thermal margins, including the Critical Power Ratio (CPR). The impact of the multiple chimney (MC) versus the single chimney (SC) model is studied. The multiple chimney partition modeling provides additional detail to the core flow distribution that is not considered in the single chimney model. The results confirm and add confidence that the multiple chimney partition modeling will provide improved accuracy in the ESBWR core design.
The Comparative Study on Review Models for Environmental Impact Assessment of Airborne Affluents From Nuclear Power Plant
Authors: Zhang Qiong , Guo Ruiping , Wang Bo
Published: October 2016

There are several kinds of models for the environmental impact assessment of atmospheric radioactive effluents from nuclear power plant. However, few of them were developed for the purpose of review. This paper focused on comparative study on atmospheric dispersion models to recommend a set of suitable models for the reviewing environmental impact assessment of the airborne radioactive effluents under normal operation. This paper introduced the standards, guidelines and according models in relation to the airborne radioactive effluents from nuclear power plant. The program of ROULEA-2.0, C-AIRDOS, and Fluidyn PANACH were applied for numerical simulation of airborne effluents dispersion from the CAP1400 nuclear power plant under normal operation. Typical nuclide such as 85Kr was analyzed and the model of C-AIRDOS was recommended as the adaptable model for the nuclear safety review in China.
Multi-Objective Optimization of Electric Heating Pressurizer in Nuclear Power Plant
Authors: Wang Cheng , Yan Chang-qi , Jian-jun Wang , Li Fei-fei
Published: October 2016

Electric heating pressurizer in nuclear power plant plays a key role in pressure control and protection of primary loop. Small size pressurizer fulfilling the performance requirements has been receiving an increasing amount of attention because of relatively low cost and easy installation. However, the size of pressurizer is sensitive to the thermal-hydraulic and structure parameters and it can only be determined in the thermal design of pressurizer.

In this work, a thermal-hydraulic model of pressurizer was established. Based on this model, the pressurizer inner diameter, primary loop pressure, reactor outlet coolant temperature and pressurizer spray coefficient were taken as design variables, and the weight and volume of pressurizer were taken as optimization objectives. Sensitivity analysis between the design variables and steady-state minimum water volume, steady-state minimum steam volume and steady-state power change volume was implemented respectively to investigate the influence of the variables on the pressurizer thermal hydraulic performance. Sensitivity analysis between the design variables and optimization objectives was also implemented to study the relation between them. The results show that primary loop pressure and reactor outlet coolant temperature obviously effect the fluctuation volume when a positive/negative fluctuation or a power change happens. The primary loop pressure has a negative correlation with the fluctuation volume, while the correlation between the reactor outlet coolant temperature and fluctuation volume is positive. The pressurizer spray coefficient only works in positive fluctuation because there is no need to spray in other conditions. As a structure parameter, the pressurizer inner diameter has little effect on the fluctuation, but it has obvious influence on the weight and volume of pressurizer just as other design variables. Finally, the multi-objective optimization of pressurizer aiming at minimizing the weight and volume was performed by utilizing a hybrid non-dominated sorting genetic algorithm. The optimization result is illustrated in a 2D graph. It shows that there exists a feasible region that the weight and volume of the pressurizer is as much as 10 percentage smaller compared with the original one, which indicates the validity of multi-objective optimization of pressurizer.
The Analysis of Initiating Events in PSA for TMSR
Authors: Zuo Jiaxu , Jing Jianping , Song Wei , Zhang Chunming
Published: October 2016

The initiation events analysis and evaluation were the beginning of nuclear safety analysis and probabilistic safety assessment, and it was the key points of the nuclear safety analysis. The main methods of the initiation events analysis are reference to existing lists and reports, operating experience, project evaluation and logic diagrams analysis. Currently, the initiation events analysis method and experiences both focused on pressurized water reactor but there are no general theories for Fluoride Salt-Cooled High Temperature Reactor (FHR). With FHR’s research and development, the initiation events analysis and evaluation was increasingly important. Based on the FHR’s design, the theories and methods of initiation events analysis would be researched and developed. From the FHR’s design, the systems, subsystems and components are divided to identify the safety functions of them. Base on the safety functions, the logical analysis and accident analysis calculation method would be combined to study FHR’s initiation events. The theory of analysis would be developed and the analysis method system would be discussed. Finally, the preliminary initiation events list of FHR will be discussed and researched. The results would help TMSR’s reactor designs and nuclear safety analysis.
Overview of Code Structures, Challenges and Available Methodologies for Treatment of Model Uncertainty in Severe Accident Calculations
Authors: Hoseyni Seyed Mohsen , Pourgol-Mohammad Mohammad
Published: October 2016

In spite of being a significant source of uncertainty, “Model Uncertainty” is ignored in most of engineering applications. The influence of model uncertainty is most pronounced for areas with limited knowledge and complex simulations structures like severe accident calculations; however lack of a systematic methodology makes this assessment a challenge. The present study is devoted to the treatment of model uncertainty in severe accident analysis for nuclear power plants. After a review of available methodologies for model uncertainty treatment in different applications, the unique features are described for the severe accident problems with supportive examples from the real calculations. By reviewing available approaches in engineering and science as well as the structure of severe accident codes, challenges are discussed for model uncertainty assessment in this area. This paper initiates a systematic examination at the subject.
Adaptive LMR Simulation of DDT in Obstructed Channel
Authors: Ren Ke , Kotchourko Alexei , Lelyakin Alexander
Published: October 2016

Deflagration to detonation transition (DDT) is a challenging subject in computational fluid dynamics both from a standpoint of the phenomenon nature understanding and from extremely demanding computational efforts. In recent years, as the development of computer technology and improvement of numerical schemes was achieved, some more direct methods have been found to reproduce the DDT mechanistically without additional numerical or physical models. In the current work, highly resolved DDT simulations of hydrogen-air and of hydrogen-oxygen mixtures in 2D channel with regular repeating obstacles are present. The technique of local mesh refinement (ALMR) is implemented in the simulations to minimize the computational efforts. The criteria for the ALMR are examined and optimized in simulations.
HIPed Hard Facings for Nuclear Applications: Materials, Key Potential Defects and Mitigating Quality Control Measures
Authors: Sulley John , Stewart David
Published: October 2016

Hard facings are used in a number of different types of components generally to provide improved wear, erosion, and corrosion resistance to the substrate. A typical application is to a valve seat which may be subjected to high wear loads and high flow rates such that a hard wearing surface is required.

Traditionally, a common application method has been to weld deposit the hard facing onto a softer substrate, e.g. the main body material of the component. This can result in poor quality micro-structures, e.g. cast/inhomogeneous structures being created that may not provide the required wear/erosion/corrosion resistance. This can be a particular issue for Nuclear applications where the hard facing is cobalt based. If the facing deteriorates and releases cobalt based debris, the debris (crud), if it becomes activated, can contribute significantly to the overall plant radiation activation level. Also, depending upon the geometry, deposition process, the expansion coefficient difference between the facing and substrate, and the cooling rate, a detrimental tensile residual stress can be generated. This can cause cracking of the facing which, depending upon the in-service loading conditions, could lead to crack propagation into the substrate, potentially threatening the structural integrity of the component; a leak or structural failure could result.

One application method to address the potential poor micro-structure that may be created from weld deposition methods, is to use a Hot Isostatically Pressed (HIPed) hard facing. This is where a wear surface is created from the solid state, rather than using a localised melting route, by the HIP consolidation of powder produced by a gas atomisation process. Homogenous, isotropic, finer grained, and defect free microstructures can be created via this method which generally exhibit improved resistance to wear/erosion/corrosion. Also, where the HIP consolidated facing is HIP bonded to the substrate, a beneficial compressive residual stress is created that can arrest any crack propagation into the substrate if cracking of the facing was to occur.

For Nuclear applications it is imperative the material quality of a hard facing is assured. It is essential that care is taken particularly in the production of the powder to ensure it does not contain undesirable defects/contamination.

This paper presents: the benefits that can be achieved with creating component hard facings using the HIP process, the key defects/contamination that may be present, and the quality control measures recommended to assure the material quality.
A Parametric Study for the Seismic Response Analysis of a Nuclear Reactor Building by Using a Three-Dimensional Finite Element Model
Authors: Choi Byunghyun , Nishida Akemi , Nakajima Norihiro
Published: October 2016

Research and development of three-dimensional vibration simulation technologies for nuclear facilities is one mission of the Center for Computational Science and e-Systems of the Japan Atomic Energy Agency (JAEA). A seismic intensity of upper 5 was observed in the area of High-Temperature Engineering Test Reactor (HTTR) at the Oarai Research and Development Center of JAEA during the 2011 Tohoku earthquake. In this paper, we report a seismic response analysis of this earthquake using three-dimensional models of the HTTR building. We performed a parametric study by using uncertainty parameters. Furthermore, we examined the variation in the response result for the uncertainty parameters to create a valid 3D finite element model.
Hydraulic Balance Characteristics of an Innovative Bottom Nozzle Design With Angled Trailing Edge
Authors: Yu Wenchi
Published: October 2016

The purpose of this study is to analyze the hydraulic characteristics of adapter plate with angled trailing edge in the bottom nozzle design for the self-reliant nuclear fuel development plan. Hydraulic behavior and pressure drop were calculated by using Computational Fluid Dynamics, which is an ANSYS CFX program. Several models for analysis were selected according to factors influencing the hydraulic. Each analysis model was classified by the depths of angled trailing edge on bottom nozzle flow plate with respect to the reference design. Bottom nozzle flow plate with angled trailing edge showed the lower pressure drop. Different from conventional design, angled trailing edge ensure flow area changing smoothly along the FA longitude, and nozzles with this feature have lower pressure drop. Angled trailing edges also provide a passage of flow exchange, making the flow more evenly distributed. Bottom nozzles with angled trailing edge also show better performance than the former design in hydraulic balance.
A Thermal Hydraulic Phenomenon Based Review on the Validation Matrix of Several Reactor Safety Analysis Systems Codes
Authors: Liao Jun , Fortune Scott E.
Published: October 2016

The systems computer code is a key part of the evaluation model for safety analysis of nuclear reactors. The systems code utilizes a set of governing equation that is simplified from the fundamental Navier-Stokes equations and closure models to describe the transport of mass, momentum, and energy of single phase or multiphase fluid throughout the reactor coolant systems. Following the Evaluation Model Development and Assessment Process, an assessment matrix is established where Separate Effects Tests and Integral Effects Tests are selected based on phenomena identification and ranking table. The purpose of the assessment matrix is to validate the systems code against the important phenomena for the safety analysis. The code biases and uncertainties are established and the effect of scale could then be determined. The assessment matrices of major systems codes, RELAP5/MOD3, TRACE Ver.5.0 and WCOBRA/TRAC-TF2, for the reactor safety analysis are reviewed and compared in this study for the Loss of Coolant Accident (LOCA) safety analysis perspectives. The scenarios are divided into small break LOCA and large break LOCA. The phenomena bases of the separate effects tests in those assessment matrices are discussed following its PIRT. The comparison demonstrates the capability of each systems code.
Selective deposition of Ta2O5 by adding plasma etching super-cycles in plasma enhanced atomic layer deposition steps
Authors: Vallat Rémi , Gassilloud Rémy , Eychenne Brice , Vallée Christophe
Published: October 2016

In this paper, a new route for a selective deposition of thin oxide by atomic layer deposition is discussed. The proposed process is using super cycles made of an additional plasma etching step in a standard plasma enhanced atomic layer deposition (PEALD) process. This allows the selective growth of a thin oxide on a metal substrate without a specific surface deactivation by means of self assembled monolayer. It is shown that adding a small amount of NF3 etching gas to an oxygen plasma gas every eight cycles of the PEALD process helps to fully remove the Ta2O5 layer on Si and/or SiO2 surface while keeping few nanometers of Ta2O5 on the TiN substrate. NF3 addition is also used to increase the incubation time before Ta2O5 growth on Si or SiO2 substrate. In this way, a selective deposition of Ta2O5 on the TiN substrate is obtained with properties (density, leakage current…) similar to the ones obtained in a conventional PEALD mode. Hence, the authors demonstrate that a future for selective deposition could be a process using both PEALD and atomic layer etching.
Combined Systems Approaches Reveal a Multistage Mode of Action of a Marine Antimicrobial Peptide against Pathogenic Escherichia coli and Its Protective Effect against Bacterial Peritonitis and Endotoxemia
Authors: Wang Xiumin , Teng Da , Mao Ruoyu , Yang Na , Hao Ya , Wang Jianhua
Published: October 2016

A marine arenicin-3 derivative, N4, displayed potent antibacterial activity against Gram-negative bacteria, but its antibacterial mode of action remains elusive. The mechanism of action of N4 against pathogenic
Escherichia coli
was first researched by combined cytological and transcriptomic techniques in this study. The N4 peptide permeabilized the outer membrane within 1 min, disrupted the plasma membrane after 0.5 h, and localized in the cytoplasm within 5 min. Gel retardation and circular dichroism (CD) spectrum analyses demonstrated that N4 bound specifically to DNA and disrupted the DNA conformation from the B type to the C type. N4 inhibited 21.1% of the DNA and 20.6% of the RNA synthesis within 15 min. Several hallmarks of apoptosis-like cell death were exhibited by N4-induced
E. coli
, such as cell cycle arrest in the replication (R) and division(D) phases, reactive oxygen species production, depolarization of the plasma membrane potential, and chromatin condensation within 0.5 h. Deformed cell morphology, disappearance of the plasma membrane, leakage of the contents, and ghost cell formation were demonstrated by transmission electron microscopy, and nearly 100% of the bacteria were killed by N4. A total of 428 to 663 differentially expressed genes are involved in the response to N4, which are associated mainly with membrane biogenesis (53.9% to 56.7%) and DNA binding (13.3% to 14.9%). N4-protected mice that were lethally challenged with lipopolysaccharide (LPS) exhibited reduced levels of interleukin-6 (IL-6), IL-1β, and tumor necrosis factor alpha (TNF-α) in serum and protected the lungs from LPS-induced injury. These data facilitate an enhanced understanding of the mechanisms of marine antimicrobial peptides (AMPs) against Gram-negative bacteria and provide guidelines in developing and applying novel multitarget AMPs in the field of unlimited marine resources as therapeutics.
Efficacy of Doxycycline in the Treatment of Syphilis
Authors: Dai Ting , Qu Rui , Liu Jinfen , Zhou Pingyu , Wang Qianqiu
Published: October 2016

Doxycycline is an alternative antibiotic drug for the treatment of syphilis, but data on its efficacy, especially data on its efficacy against late latent syphilis, are limited. A retrospective study was conducted to evaluate the effectiveness of doxycycline for the treatment of patients with different stages of syphilis. Patients who received doxycycline treatment between June 2011 and June 2014 were involved. The serological response to doxycycline was defined as either a negative toluidine red unheated serum test (TRUST) result or a ≥4-fold decrease in titer at 12 months following the treatment. Univariate and multivariate logistic regression analyses were performed to identify factors associated with the serological response. During the study period, a total of 163 syphilis patients were treated with doxycycline, and 118 patients completed doxycycline treatment and the 12-month follow-up. Among the 118 patients, the serological response rate at 12 months was 100.0% (7/7) in patients with primary syphilis, 96.9% (62/64) in patients with secondary syphilis, 91.3% (21/23) in patients with early latent syphilis, and 79.2% (19/24) in patients with late latent syphilis. The total serological response rates were 92.4% (109/118) for preprotocol (PP) patients and 66.9% (109/163) for all intention-to-treat (ITT) patients. In multivariate analysis, patients who serologically responded at 12 months following treatment were positively associated with a higher baseline TRUST titer and an earlier syphilis stage than nonresponders. Our study showed excellent treatment outcomes in patients with different stages of syphilis. Our data, along with those from other reports, support the usage of doxycycline as a good alternative therapeutic option in the treatment of syphilis.
The Colicin E1 TolC Box: Identification of a Domain Required for Colicin E1 Cytotoxicity and TolC Binding
Authors: Jakes Karen S.
Published: October 2016

Colicins are protein toxins made by
Escherichia coli
to kill related bacteria that compete for scarce resources. All colicins must cross the target cell outer membrane in order to reach their intracellular targets. Normally, the first step in the intoxication process is the tight binding of the colicin to an outer membrane receptor protein via its central receptor-binding domain. It is shown here that for one colicin, E1, that step, although it greatly increases the efficiency of killing, is not absolutely necessary. For colicin E1, the second step, translocation, relies on the outer membrane/transperiplasmic protein TolC. The normal role of TolC in bacteria is as an essential component of a family of tripartite drug and toxin exporters, but for colicin E1, it is essential for its import. Colicin E1 and some N-terminal translocation domain peptides had been shown previously to bind
in vitro
to TolC and occlude channels made by TolC in planar lipid bilayer membranes. Here, a set of increasingly shorter colicin E1 translocation domain peptides was shown to bind to
Escherichia coli
in vivo
and protect them from subsequent challenge by colicin E1. A segment of only 21 residues, the “TolC box,” was thereby defined; that segment is essential for colicin E1 cytotoxicity and for binding of translocation domain peptides to TolC.

IMPORTANCE
The
Escherichia coli
outer membrane/transperiplasmic protein TolC is normally an essential component of the bacterium's tripartite drug and toxin export machinery. The protein toxin colicin E1 instead uses TolC for its import into the cells that it kills, thereby subverting its normal role. Increasingly shorter constructs of the colicin's N-terminal translocation domain were used to define an essential 21-residue segment that is required for both colicin cytotoxicity and for binding of the colicin's translocation domain to bacteria, in order to protect them from subsequent challenge by active colicin E1. Thus, an essential TolC binding sequence of colicin E1 was identified and may ultimately lead to the development of drugs to block the bacterial drug export pathway.
The Regulatory Function of Eosinophils
Authors: Wen Ting , Rothenberg Marc E.
Published: October 2016

Eosinophils are a minority circulating granulocyte classically viewed as being involved in host defense against parasites and promoting allergic reactions. However, a series of new regulatory functions for these cells have been identified in the past decade. During homeostasis, eosinophils develop in the bone marrow and migrate from the blood into target tissues following an eotaxin gradient, with interleukin-5 being a key cytokine for eosinophil proliferation, survival, and priming. In multiple target tissues, eosinophils actively regulate a variety of immune functions through their vast arsenal of granule products and cytokines, as well as direct cellular interaction with cells in proximity. The immunologic regulation of eosinophils extends from innate immunity to adaptive immunity and also involves non-immune cells. Herein, we summarize recent findings regarding novel roles of murine and human eosinophils, focusing on interactions with other hematopoietic cells. We also review new experimental tools available and remaining questions to uncover a greater understanding of this enigmatic cell.
Lectin Receptors Expressed on Myeloid Cells
Authors: Brown Gordon D. , Crocker Paul R.
Published: October 2016

Lectins recognize a diverse array of carbohydrate structures and perform numerous essential biological functions. Here we focus on only two families of lectins, the Siglecs and C-type lectins. Triggering of intracellular signaling cascades following ligand recognition by these receptors can have profound effects on the induction and modulation of immunity. In this chapter, we provide a brief overview of each family and then focus on selected examples that highlight how these lectins can influence myeloid cell functioning in health and disease. Receptors that are discussed include Sn (Siglec-1), CD33 (Siglec-3), and Siglec-5, -7, -8, -9, -10, -11, -14, -15, -E, -F, and -G as well as Dectin-1, MICL, Dectin-2, Mincle/MCL, and the macrophage mannose receptor.
Clinical Presentations and Epidemiology of Urinary Tract Infections
Authors: Geerlings Suzanne E.
Published: October 2016

Urinary tract infection (UTI) is one of the most common bacterial infections, and the incidence in women is much higher than in men. The diagnosis of a UTI can be made based on a combination of symptoms and a positive urine analysis or culture. Most UTIs are uncomplicated UTIs, defined as cystitis in a woman who is not pregnant, is not immunocompromised, has no anatomical and functional abnormalities of the urogenital tract, and does not exhibit signs of tissue invasion and systemic infection. All UTIs that are not uncomplicated are considered to be complicated UTIs. Differentiation between uncomplicated and complicated UTIs has implications for therapy because the risks of complications or treatment failure are increased for patients with a complicated UTI. Asymptomatic bacteriuria (ASB) is defined as the presence of a positive urine culture collected from a patient without symptoms of a UTI. Concerning the complicated UTI, it is possible to make a differentiation between UTI with systemic symptoms (febrile UTI) and UTI in a host, which carries an increased risk to develop complications of this UTI. Febrile UTIs are urosepsis, pyelonephritis, and prostatitis. A complicated host is defined as one that has an increased risk for complications, to which the following groups belong: men, pregnant women, immunocompromised patients, or those who have an anatomical or functional abnormality of the urogenital tract (e.g., spinal cord-injury patients, renal stones, urinary catheter).
Effects of Electroacupuncture and the Retinoid X Receptor (Rxr) Signalling Pathway on Oligodendrocyte Differentiation in the Demyelinated Spinal Cord of Rats
Authors: Yang Xiao-Hua , Ding Ying , Li Wen , Zhang Rong-Yi , Wu Jin-Lang , Ling Eng-Ang , Wu Wutian , Zeng Yuan-shan
Published: October 2016

Objectives

In spinal cord demyelination, some oligodendrocyte precursor cells (OPCs) remain in the demyelinated region but have a reduced capacity to differentiate into oligodendrocytes. This study investigated whether ‘Governor Vessel’ (GV) electroacupuncture (EA) would promote the differentiation of endogenous OPCs into oligodendrocytes by activating the retinoid X receptor γ (RXR-γ)-mediated signalling pathway.

Methods

Adult rats were microinjected with ethidium bromide (EB) into the T10 spinal cord to establish a model of spinal cord demyelination. EB-injected rats remained untreated (EB group, n=26) or received EA treatment (EB+EA group, n=26). A control group (n=26) was also included that underwent dural exposure without EB injection. After euthanasia at 7 days (n=5 per group), 15 days (n=8 per group) or 30 days (n=13 per group), protein expression of RXR-γ in the demyelinated spinal cord was evaluated by immunohistochemistry and Western blotting. In addition, OPCs derived from rat embryonic spinal cord were cultured in vitro, and exogenous 9-cis-RA (retinoic acid) and RXR-γ antagonist HX531 were administered to determine whether RA could activate RXR-γ and promote OPC differentiation.

Results

EA was found to increase the numbers of both OPCs and oligodendrocytes expressing RXR-γ and RALDH2, and promote remyelination in the remyelinated spinal cord. Exogenous 9-cis-RA enhanced the differentiation of OPCs into mature oligodendrocytes by activating RXR-γ.

Conclusions

The results suggest that EA may activate RXR signalling to promote the differentiation of OPCs into oligodendrocytes in spinal cord demyelination.
Intravenous thrombolysis in a patient taking warfarin with an international normalised ratio of 1.9
Authors: Kefas Joanna , Bhandari Mohit , Bhatt Naman
Published: October 2016

Intravenous thrombolysis is the mainstay medical treatment for acute ischaemic strokes, but has strict eligibility criteria. Symptomatic intracranial haemorrhage (sICH) is the most adverse complication. A woman aged 76 years presented with signs of an acute stroke and despite not meeting the eligibility criteria, given her background use of warfarin, she received intravenous thrombolysis with an excellent outcome. This is the first fully documented case report of the contraindicated use of intravenous thrombolysis in a patient presenting with an acute ischaemic stroke on a background of concurrent use of warfarin with an international normalised ratio (INR) as high as 1.9. It has been perceived that the risk of thrombolysis with a raised INR outweighs the potential benefits. However, documenting its use outside of the current eligibility criteria is key to future developments.
Systematic review and meta-analysis of the adolescent HIV continuum of care in South Africa: the Cresting Wave
Authors: Zanoni Brian C , Archary Moherndran , Buchan Sarah , Katz Ingrid T , Haberer Jessica E
Published: October 2016

Context

South Africa has the most HIV infections of any country in the world, yet little is known about the adolescent continuum of care from HIV diagnosis through viral suppression.

Objective

To determine the adolescent HIV continuum of care in South Africa.

Data sources

We searched PubMed, Google Scholar and online conference proceedings from International AIDS Society (IAS), International AIDS Conference (AIDS) and Conference on Retrovirology and Opportunistic Infections (CROI) from 1 January 2005 to 31 July 2015.

Data extraction

We selected published literature containing South African cohorts and epidemiological data reporting primary data for youth (15–24 years of age) at any stage of the HIV continuum of care (ie, diagnosis, treatment, retention, viral suppression). For the meta-analysis we used six sources for retention in care and nine for viral suppression.

Results

Among the estimated 867 283 HIV-infected youth from 15 to 24 years old in South Africa in 2013, 14% accessed antiretroviral therapy (ART). Of those on therapy, ∼83% were retained in care and 81% were virally suppressed. Overall, we estimate that 10% of HIV-infected youth in South Africa in 2013 were virally suppressed.

Limitations

This analysis relies on published data from large mostly urban South Africa cohorts limiting the generalisability to all adolescents.

Conclusions

Despite a large increase in ART programmes in South Africa that have relatively high retention rates and viral suppression rates among HIV-infected youth, only a small percentage are virally suppressed, largely due to low numbers of adolescents and young adults accessing ART.
Does subjective sleep quality improve by a walking intervention? A real-world study in a Japanese workplace
Authors: Hori Hikaru , Ikenouchi-Sugita Atsuko , Yoshimura Reiji , Nakamura Jun
Published: October 2016

Objectives

The purpose of this study was to evaluate the impact of a 4-week walking intervention on subjective sleep quality.

Design

A prospective open-label study.

Participants

A total of 490 healthy workers were included in the study. The 490 participants were divided into a group of 214 participants with exercise habits (exercising group, EG) and a group of 276 participants without exercise habits (non-EG).

Interventions

A walking intervention with a target of walking 10 000 steps daily for 4 weeks.

Outcome measures

The Pittsburgh Sleep Quality Index (PSQI) questionnaire was administered twice (before the start and after the end of the study).

Results

Overall, the walking intervention improved the participants’ PSQI global score, sleep latency (minutes), sleep duration (hours), perceived sleep quality factor and daily disturbance factor. Among the EG participants, the walking intervention significantly improved the PSQI global score and perceived sleep quality. Among the non-EG participants, the walking intervention significantly improved the PSQI global score, sleep latency, sleep duration and perceived sleep quality.

Conclusions

A walking intervention might reduce the sleep latency and increase total sleep duration in working persons without exercise habits.
Efficacy of various types of laryngoscope (direct, Pentax Airway Scope and GlideScope) for endotracheal intubation in various cervical immobilisation scenarios: a randomised cross-over simulation study
Authors: Kim Jong Won , Lee Kyeong Ryong , Hong Dae Young , Baek Kwang Je , Lee Young Hwan , Park Sang O
Published: October 2016

Objective

To compare the efficacy of direct laryngoscopy (DL), Pentax Airway Scope (PAWS) and GlideScope video laryngoscope (GVL) systems for endotracheal intubation (ETI) in various cervical immobilisation scenarios: manual in-line stabilisation (MILS), Philadelphia neck collar (PNC) (moderate limit of mouth opening) and Stifneck collar (SNC) (severe limit of mouth opening).

Design

Randomised cross-over simulation study.

Setting and Participants

35 physicians who had >30 successful ETI experiences at a tertiary hospital in Seoul, Korea.

Primary and secondary outcome measures

Participants performed ETI using PAWS, GVL and DL randomly in simulated MILS, PNC and SNC scenarios in our simulation centre. The end points were successful ETI and the time to complete ETI. In addition, modified Cormack-Lehane (CL) classification and pressure to teeth were recorded.

Results

In MILS, there were no significant differences in the rate of success of ETI between the three devices: 33/35(94.3%) for DL vs 32/35(91.4%) for GVL vs 35/35(100.0%) for PAWS; p=0.230). PAWS achieved successful ETI more quickly (19.8 s) than DL (29.6 s) and GVL (35.4 s). For the PNC scenario, a higher rate of successful ETI was achieved with GVL 33/35 (94.3%) than PAWS 29/35 (82.9%) or DL 25/35 (71.4%) (p=0.040). For the SNC scenario, a higher rate of successful ETI was achieved with GVL 28/35(80.0%) than with DL 14/35(40.0%) and PAWS 7/35(20.0%) (p<0.001). For the PNC and SNC scenarios, GVL provided a relatively good view of the glottis, but a frequent pressure to teeth occurred.

Conclusions

All three devices are suitable for ETI in MILS. DL is not suitable in both neck collar scenarios. PAWS showed faster intubations in MILS, but was not suitable in the SNC scenario. GVL is most suitable in all cervical immobilisation scenarios, but may cause pressure to teeth more frequently.
Ambulance smartphone tool for field triage of ruptured aortic aneurysms (FILTR): study protocol for a prospective observational validation of diagnostic accuracy
Authors: Lewis Thomas L , Fothergill Rachael T ,   Aneurysm-FILTR Study Group, Karthikesalingam Alan
Published: October 2016

Introduction

Rupture of an abdominal aortic aneurysm (rAAA) carries a considerable mortality rate and is often fatal. rAAA can be treated through open or endovascular surgical intervention and it is possible that more rapid access to definitive intervention might be a key aspect of improving mortality for rAAA. Diagnosis is not always straightforward with up to 42% of rAAA initially misdiagnosed, introducing potentially harmful delay. There is a need for an effective clinical decision support tool for accurate prehospital diagnosis and triage to enable transfer to an appropriate centre.

Methods and analysis

Prospective multicentre observational study assessing the diagnostic accuracy of a prehospital smartphone triage tool for detection of rAAA. The study will be conducted across London in conjunction with London Ambulance Service (LAS). A logistic score predicting the risk of rAAA by assessing ten key parameters was developed and retrospectively validated through logistic regression analysis of ambulance records and Hospital Episode Statistics data for 2200 patients from 2005 to 2010. The triage tool is integrated into a secure mobile app for major smartphone platforms. Key parameters collected from the app will be retrospectively matched with final hospital discharge diagnosis for each patient encounter. The primary outcome is to assess the sensitivity, specificity and positive predictive value of the rAAA triage tool logistic score in prospective use as a mob app for prehospital ambulance clinicians. Data collection started in November 2014 and the study will recruit a minimum of 1150 non-consecutive patients over a time period of 2 years.

Ethics and dissemination

Full ethical approval has been gained for this study. The results of this study will be disseminated in peer-reviewed publications, and international/national presentations.

Trial registration number

CPMS 16459; pre-results.
Impact of referral templates on patient experience of the referral and care process: a cluster randomised trial
Authors: Wåhlberg Henrik , Braaten Tonje , Broderstad Ann Ragnhild
Published: October 2016

Objectives

To evaluate if a referral intervention improves the patient experience of the referral and treatment process.

Setting

Interface between 14 primary care surgeries and a district general hospital.

Participants

The 14 general practitioner (GP) surgeries (7 intervention, 7 control) in the area around the University Hospital of North Norway Harstad were randomised and all completed the study. Consecutive individual patients were recruited at their hospital appointment. A total of 500 patients were recruited with 281 in the intervention and 219 in the control arm.

Interventions

Dissemination of referral templates for 4 diagnostic groups (dyspepsia, suspected colorectal cancer, chest pain and chronic obstructive pulmonary disease) coupled with intermittent surgery visits by study personnel. The control arm continued standard referral practice. The intervention was in use for 2.5 years.

Outcome

The main outcome was a quality indicator score. This paper reports a secondary outcome, the patient experience, as measured by self-report questionnaires. GPs in the intervention group could not be blinded. Patients were blinded to intervention status. Analysis was based on single-question comparison with a questionnaire subscore used to assess the effect of clustering.

Results

On the individual questions, overall satisfaction was very high with minor differences between the intervention and control group. Interestingly, the most negative responses, in both groups concerned questions relating to patient interaction and information. Very little evidence of clustering was found with an estimated intracluster correlations coefficient at 1.21e−11.

Conclusions

In total, this indicates no clear effect of the implementation of referral templates on the patient experience, in a setting of generally high patient satisfaction.

Trial registration number

NCT01470963; Results.
Factors important for women who breastfeed in public: a content analysis of review data from FeedFinder
Authors: Simpson Emma , Garbett Andrew , Comber Rob , Balaam Madeline
Published: October 2016

Objective

To examine how the breastfeeding experience is represented by users of FeedFinder (a mobile phone application for finding, reviewing and sharing places to breastfeed in public).

Design

Content analysis using FeedFinder database.

Setting

FeedFinder, UK, September 2013–June 2015.

Methods

Reviews obtained through FeedFinder over a period of 21 months were systematically coded using a conventional content analysis approach, average review scores were calculated for the rating criteria in FeedFinder (comfort, hygiene, privacy, baby facilities) and review texts were analysed for sentiment. We used data from Foursquare to describe the type of venues visited and cross-referenced the location of venues with the Indices of Multiple Deprivation.

Results

A total of 1757 reviews were analysed. Of all the reviews obtained, 80% of those were classified as positive, 15.4% were classified as neutral and 4.3% were classified as negative. Important factors that were discussed by women include facilities, service, level of privacy available and qualities of a venue. The majority of venues were classified as cafes (26.4%), shops (24.4%) and pubs (13.4%). Data on IMD were available for 1229 venues mapped within FeedFinder, 23% were located within the most deprived quintile and 16% were located in the least deprived quintile.

Conclusions

Women create content that is positive and informative when describing their breastfeeding experience in public. Public health bodies and business owners have the potential to use the data from FeedFinder to impact on service provision. Further work is needed to explore the demographic differences that may help to tailor public health interventions aimed at increasing breastfeeding rates in the UK.
Birth cohort trends in the global epidemiology of alcohol use and alcohol-related harms in men and women: systematic review and metaregression
Authors: Slade Tim , Chapman Cath , Swift Wendy , Keyes Katherine , Tonks Zoe , Teesson Maree
Published: October 2016

Objective

Historically, alcohol use and related harms are more prevalent in men than in women. However, emerging evidence suggests the epidemiology of alcohol use is changing in younger cohorts. The current study aimed to systematically summarise published literature on birth cohort changes in male-to-female ratios in indicators of alcohol use and related harms.

Methods

We identified 68 studies that met inclusion criteria. We calculated male-to-female ratios for 3 broad categories of alcohol use and harms (any alcohol use, problematic alcohol use and alcohol-related harms) stratified by 5-year birth cohorts ranging from 1891 to 2001, generating 1568 sex ratios. Random-effects meta-analyses produced pooled sex ratios within these 3 categories separately for each birth cohort.

Findings

There was a linear decrease over time in the sex ratio for all 3 categories of alcohol use and related harms. Among those born in the early 1900s, males were 2.2 (95% CI 1.9 to 2.5) times more likely than females to consume alcohol, 3.0 (95% CI 1.5 to 6.0) times more likely to drink alcohol in ways suggestive of problematic use and 3.6 (95% CI 0.4 to 30.3) times more likely to experience alcohol-related harms. Among cohorts born in the late 1900s, males were 1.1 (95% CI 1.1 to 1.2) times more likely than females to consume alcohol, 1.2 (95% CI 1.1 to 1.4) times more likely to drink alcohol in ways suggestive of problematic use and 1.3 (95% CI 1.2 to 1.3) times more likely to experience alcohol-related harms.

Conclusions

Findings confirm the closing male–female gap in indicators of alcohol use and related harms. The closing male–female gap is most evident among young adults, highlighting the importance of prospectively tracking young male and female cohorts as they age into their 30s, 40s and beyond.
Why do general practitioners prescribe antibiotics for upper respiratory tract infections to meet patient expectations: a mixed methods study
Authors: Fletcher-Lartey Stephanie , Yee Melissa , Gaarslev Christina , Khan Rabia
Published: October 2016

Objectives

To describe the role patient expectations play in general practitioners (GPs) antibiotic prescribing for upper respiratory tract infections (URTI).

Methods

Concurrent explanatory mixed methods approach using a cross-sectional survey and semistructured interviews.

Settings

Primary care GPs in Australia.

Participants

584 GPs (response rate of 23.6%) completed the cross-sectional survey. 32 GPs were interviewed individually.

Outcome measure

Prescribing of antibiotics for URTI.

Results

More than half the GP respondents to the survey in Australia self-reported that they would prescribe antibiotics for an URTI to meet patient expectations. Our qualitative findings suggest that ‘patient expectations’ may be the main reason given for inappropriate prescribing, but it is an all-encompassing phrase that includes other reasons. These include limited time, poor doctor–patient communication and diagnostic uncertainty. We have identified three role archetypes to explain the behaviour of GPs in reference to antibiotic prescribing for URTIs. The main themes emerging from the qualitative component was that many GPs did not think that antibiotic prescribing in primary care was responsible for the development of antibiotic resistance nor that their individual prescribing would make any difference in light of other bigger issues like hospital prescribing or veterinary use. For them, there were negligible negative consequences from their inappropriate prescribing.

Conclusions

There is a need to increase awareness of the scope and magnitude of antibiotic resistance and the role primary care prescribing plays, and of the contribution of individual prescribing decisions to the problem of antibiotic resistance.