bluuebunny/crossref_metadata_2025_split huggingface dataset:
Barriers Associated With Evidence‐Based Practice Among Nurses in Low‐ and Middle‐Income Countries: A Systematic Review
Authors: Shayan Shah Jahan , Kiwanuka Frank , Nakaye Zainah 
Published: January 2019

AbstractBackgroundEvidence‐based practice (EBP) is both a goal and an approach that requires a combination of clinical experience with the most credible recent research evidence when making decisions in healthcare practice. The approach has been widely embraced; however, an evidence‐to‐practice gap still exists.AimTo assess barriers to EBP among nurses in low‐ and middle‐income countries.MethodsThis review conforms to the PRISMA statement. Databases PubMed, Scopus, EMBASE, and Web of Science/Knowledge were searched using a combination of keywords that included “barriers,” “evidence‐based practice,” and “nurses.” The references of the selected articles were also hand‐searched to obtain additional relevant articles. Studies published in peer‐reviewed journals in English between 2000 and 2018 were included in the review.ResultsSixteen articles were included in the analysis, with a total number of 8,409 participants. Both qualitative and quantitative studies were included in the review. Three main themes emerged from eight categories found. The three main themes were institutional‐related barriers, interdisciplinary barriers, and nurse‐related barriers. The theme of institutional‐related barriers emerged from four categories, which included scant resources, limited access to information, inadequate staffing, and lack of institutional support. The theme of interdisciplinary barriers emerged from subcategories that included lack of communication between academic and clinical practice environments, inconsistency between education and practice in the nursing discipline, lack of teamwork, and the public's negative image about the nursing profession. Finally, the theme of nurse‐related barriers emerged from categories including perceived limitations in the scope of nurses’ practice, time, knowledge of EBP, and individual‐related barriers.Linking Evidence to ActionThese findings may guide the design of future interventions aimed at fostering EBP. Implementing EBP in practice should be systematic and requires institutional will and interdisciplinary and individual commitment. It should be a collective goal and a win‐win situation for nurses, clinicians, and healthcare organizations.
Functional assessment of triheteromeric NMDA receptors containing a human variant associated with epilepsy
Authors: Marwick Katie F. M. , Hansen Kasper B. , Skehel Paul A. , Hardingham Giles E. , Wyllie David J. A. 
Published: January 2019

Key points
NMDA receptors are neurotransmitter‐gated ion channels that are critically involved in brain cell communication
Variations in genes encoding NMDA receptor subunits have been found in a range of neurodevelopmental disorders.
We investigated a de novo genetic variant found in patients with epileptic encephalopathy that changes a residue located in the ion channel pore of the GluN2A NMDA receptor subunit.
We found that this variant (GluN2AN615K) impairs physiologically important receptor properties: it markedly reduces Mg2+ blockade and channel conductance, even for receptors in which one GluN2AN615K is co‐assembled with one wild‐type GluN2A subunit.
Our findings are consistent with the GluN2AN615K mutation being the primary cause of the severe neurodevelopmental disorder in carriers.
AbstractNMDA receptors are ionotropic calcium‐permeable glutamate receptors with a voltage‐dependence mediated by blockade by Mg2+. Their activation is important in signal transduction, as well as synapse formation and maintenance. Two unrelated individuals with epileptic encephalopathy carry a de novo variant in the gene encoding the GluN2A NMDA receptor subunit: a N615K missense variant in the M2 pore helix (GRIN2AC1845A). We hypothesized that this variant underlies the neurodevelopmental disorders in carriers and explored its functional consequences by electrophysiological analysis in heterologous systems. We focused on GluN2AN615K co‐expressed with wild‐type GluN2 subunits in physiologically relevant triheteromeric NMDA receptors containing two GluN1 and two distinct GluN2 subunits, whereas previous studies have investigated the impact of the variant in diheteromeric NMDA receptors with two GluN1 and two identical GluN2 subunits. We found that GluN2AN615K‐containing triheteromers showed markedly reduced Mg2+ blockade, with a value intermediate between GluN2AN615K diheteromers and wild‐type NMDA receptors. Single‐channel conductance was reduced by four‐fold in GluN2AN615K diheteromers, again with an intermediate value in GluN2AN615K‐containing triheteromers. Glutamate deactivation rates were unaffected. Furthermore, we expressed GluN2AN615K in cultured primary mouse cortical neurons, observing a decrease in Mg2+ blockade and reduction in current density, confirming that the variant continues to have significant functional impact in neuronal systems. Our results demonstrate that the GluN2AN615K variant has substantial effects on NMDA receptor properties fundamental to the roles of the receptor in synaptic plasticity, even when expressed alongside wild‐type subunits. This work strengthens the evidence indicating that the GluN2AN615K variant underlies the disabling neurodevelopmental phenotype in carriers.
Heavy Duty Engine Piston Cooling Gallery Oil Filling Ratio Measurement and Comparison of Results With Simulation
Authors: Chen Yu , Moghe Shashank 
Published: January 2019

Pistons for heavy duty diesel applications endure high thermal loads and therefore result in reduced durability. Pistons for such heavy duty applications are generally designed with an internal oil gallery — called the piston cooling gallery (PCG) — where the intent is to reduce the piston crown temperatures through forced convection cooling and thereby ensure the durability of the piston. One of the key factors influencing the efficiency of such a heat-transfer process is the volume fraction of oil inside the piston cooling gallery — defined as the filling ratio (FR) — during engine operation.
As a part of this study, a motoring engine measurement system was developed to measure the piston filling ratio of an inline-6 production heavy duty engine. In this system, multiple high precision pressure sensors were applied to the piston cooling gallery and a linkage was designed and fabricated to transfer the piston cooling gallery oil pressure signal out of the motoring engine. This pressure information was then correlated with the oil filling ratio through a series of calibration runs with known oil quantity in the piston cooling gallery. This proposed method can be used to measure the piston cooling gallery oil filling ratio for heavy duty engine pistons. A preliminary transient Computational Fluid Dynamics (CFD) analysis was performed to identify the filling ratio and transient pressures at the corresponding transducer locations in the piston cooling gallery for one of the motoring test operating speeds (1200 RPM). A mesh dependency study was performed for the CFD analysis and the results were compared against those from the motoring test.
Combustion Ionization for Detection of Misfire, Knock, and Sporadic Pre-Ignition in a Gasoline Direct Injection Engine
Authors: Ayad Samuel , Sharma Swapnil , Verma Rohan , Henein Naeim 
Published: January 2019

Detection of combustion related phenomena such as misfire, knock and sporadic preignition is very important for the development of electronic controls needed for the gasoline direct injection engines to meet the production goals in power, fuel economy, and low emissions.
This paper applies several types of combustion ionization sensors, and a pressure transducer that directly sense the in-cylinder combustion, and the knock sensor which is an accelerometer that detects the impact of combustion on engine structure vibration. Experimental investigations were conducted on a turbocharged four cylinders gasoline direct injection engine under operating conditions that produce the above phenomena. One of the cylinders is instrumented with a Piezo quartz pressure transducer, MSFI (Multi sensing fuel injector), a standalone ion current probe, and a spark plug applied to act as an ion current sensor. A comparison is made between the capabilities of the pressure transducer, ion current sensors, and the knock sensor in detecting the above phenomena. The signals from in-cylinder combustion sensors give more accurate information about combustion than the knock sensor. As far as the feasibility and cost of their application in production vehicles the spark plug sensor and MSFI appear to be the most favorable, followed by the Standalone mounted sensor which is an addition to the engine.
Experimental Investigations of Hydrogen-Natural Gas Engines for Maritime Applications
Authors: Sapra Harsh D. , Linden Youri , van Sluijs Wim , Godjevac Milinko , Visser Klaas 
Published: January 2019

A novel ship propulsion concept employs natural gas to reduce ship emissions and improve overall ship propulsion efficiency. This concept proposes a serial integration of Solid Oxide Fuel Cell (SOFC) and a natural gas engine, while anode-off gas (gas at the fuel cell exhaust) is used in the natural gas engine. This study focusses on SOFC-gas engine integration by experimentally analyzing the effects of adding hydrogen, which is the main combustible component of the fuel cell anode-off gas, in marine natural gas engines. The overall challenge is to employ the anode-off gas to improve the performance of marine natural gas engines. To study the effects of anode-off gas combustion in natural gas engines, experiments with hydrogen addition in a marine natural gas engine of 500 kW rated power were performed. Natural gas was replaced with 10 % and 20 % of hydrogen, by volume, without any penalties in terms of output power.
We found that the high combustion rate of hydrogen improved combustion stability, which allowed for better air-excess ratio control. Thus allowing leaning to higher air-excess ratios and extending the, otherwise, limited operating window. Hydrogen addition also improved brake thermal efficiency by 1.2 %, while keeping NOx emissions below the maritime emission regulations. The improvement in engine efficiency with a larger operating window may help improve the load-taking capabilities of marine natural gas engines.
Development of a New Four Valve Cylinder Head to Increase the Efficiency of a Worldwide High Reliable Gas Engine
Authors: Herdin Rüdiger , Herdin Andreas , Alten Hans , Herdin Günther , Mairegger Dominik 
Published: January 2019

Electrical efficiency is an important factor for most of the owners of gas engines. To reach a high electrical efficiency, engine manufacturers use four valve cylinder head technology on new designed engines. The change from two valve to four valve technology, in combination with optimized charge motion, can achieve an increase of electrical efficiency up to 2.5%. A significant number of engines in the market are only equipped with two valve cylinder heads, thus leaving potential to reduce carbon emissions and fuel consumption.
The scope of the paper applies to the modernization of an already well established gas engine series available on the market with a power range of 500–1100kW [1].
In the first step, the potentials were considered purely in the context of a change in configuration of the spark plug, to pre-chamber spark plug. As second step an optimization of the ports was examined. Due to the pre-existing high level of development of the combustion stage, combined with an adaption of the boost charging system, an improvement of almost 2.5% was achieved. According to data sheets, modern gas engines within this power range have efficiencies in the range of ηe ∼ 44%. The project team therefore proceeded to develop a new cylinder head along with new design leading to a better combustion. Minimizing changes around the periphery of the engine was a prerequisite in order to complete these on site as part of the 30.000-hour service. Intake- as well as exhaustport geometries were optimized with the aid of CFD tools, such that swirl and flow capacity values achieved their specified objectives. The geometries of the water jacket and valve train were also optimized through a similar methodology. These changes led to a 7% reduction in gas exchange work, which directly reflect within improved efficiency levels. Altogether, the various measures (including combustion optimization) resulted in an efficiency improvement of about 2.5% leading to an electric efficiency of 42.9%. The first endurance run shows that the mechanics match the expected technical requirements. Very low wear rates despite the increased masses of the valve train could be reached due to higher qualities in terms of materials.
The paper focuses particularly on the flow optimization in conjunction with the variables surrounding the mechanic design. Finally, the test results of the pilot engines are presented alongside an economic analysis.
CFD Analysis of Diesel-Methane Dual Fuel Low Temperature Combustion at Low Load and High Methane Substitution
Authors: Aniello Andrea , Bartolucci Lorenzo , Cordiner Stefano , Mulone Vincenzo , Krishnan Sundar R. , Srinivasan Kalyan K. 
Published: January 2019

Over the last few decades, emissions regulations for internal combustion engines have become increasingly restrictive, pushing researchers around the world to exploit innovative propulsion solutions. Among them, the dual fuel low temperature combustion (LTC) strategy has proven capable of reducing fuel consumption and while meeting emissions regulations for oxides of nitrogen (NOx) and particulate matter (PM) without problematic aftertreatment systems. However, further investigations are still needed to reduce engine-out hydrocarbon (HC) and carbon monoxide (CO) emissions as well as to extend the operational range and to further improve the performance and efficiency of dual-fuel engines.
In this scenario, the present study focuses on numerical simulation of fumigated methane-diesel dual fuel LTC in a single-cylinder research engine (SCRE) operating at low load and high methane percent energy substitution (PES). Results are validated against experimental cylinder pressure and apparent heat release rate (AHRR) data. A 3D full-cylinder RANS simulation is used to thoroughly understand the influence of the start of injection (SOI) of diesel fuel on the overall combustion behavior, clarifying the causes of AHRR transition from two-stage AHRR at late SOIs to single-stage AHRR at early SOIs, low temperature heat release (LTHR) behavior, as well as high HC production.
The numerical campaign shows that it is crucial to reliably represent the interaction between the diesel spray and the in-cylinder charge to match both local and overall methane energy fraction, which in turn, ensures a proper representation of the whole combustion. To that aim, even a slight deviation (∼3%) of the trapped mass or of the thermodynamic conditions would compromise the numerical accuracy, highlighting the importance of properly capturing all the phenomena occurring during the engine cycle.
The comparison between numerical and experimental AHRR curves shows the capability of the numerical framework proposed to correctly represent the dual-fuel combustion process, including low temperature heat release (LTHR) and the transition from two-stage to single stage AHRR with advancing SOI. The numerical simulations allow for quantitative evaluation of the residence time of vapor-phase diesel fuel inside the combustion chamber and at the same time tracking the evolution of local diesel mass fraction during ignition delay — showing their influence on the LTHR phenomena. Oxidation regions of diesel and ignition points of methane are also displayed for each case, clarifying the reasons for the observed differences in combustion evolution at different SOIs.
Evaluation of Strategies for Highly Transient Operation of Diesel-Gas Engines
Authors: Malin Maximilian , Redtenbacher Christoph , Lurf Gottfried , Wermuth Nicole , Wimmer Andreas 
Published: January 2019

The balancing of the electric grid has become more challenging due to the expansion of fluctuating renewable energy sources for electric power generation. The importance of power plants driven by internal combustion engines will increase since they can react flexibly and quickly to changes in the energy demand. With regard to the emission of pollutants and CO2, gas fueled engines are favored for gensets. However, it is more challenging to meet the dynamic load requirements with a gas engine than with a conventional diesel engine because the load acceptance of the gas engine is limited by the occurrence of knocking combustion.
Dual fuel engines are a good compromise between these two engine concepts; they can use gaseous fuel during steady state engine operation and increase the diesel share during transient modes to improve the dynamic behavior. The high number of degrees of freedom of dual fuel combustion concepts requires advanced operating strategies.
The aim of this paper is to investigate and evaluate strategies to improve the transient behavior of a 20-cylinder large bore diesel-gas engine (displacement 6.24 dm3 per cylinder) for a genset application. In the investigations, the latest turbocharging technology is applied in combination with a turbine waste gate. A wide range diesel injector that covers the whole diesel injection range of approximately 1 % to 100 % diesel fraction1 of the rated power fuel mass provides the basis for the most flexible diesel injection. A 1D simulation tool was used to model and optimize the genset in transient operation. The combustion process was simulated with Vibe heat release rate models. The optimized transient engine operating strategies were validated on a highly dynamic single cylinder research engine test bed.
The paper provides a comparison of different strategies that use these technologies to improve the dynamic behavior of the genset in island mode operation during a 50 % load step. Key to meeting the challenging requirements is an optimized diesel injection strategy or even a switch from gas operation mode to diesel operation mode during the load step. Based on the results of simulation and engine testing, potential ways to minimize engine speed drop and recovery time after the load demand increase are evaluated.
International variation in radiation dose for computed tomography examinations: prospective cohort study
Authors: Smith-Bindman Rebecca , Wang Yifei , Chu Philip , Chung Robert , Einstein Andrew J , Balcombe Jonathan , Cocker Mary , Das Marcos , Delman Bradley N , Flynn Michael , Gould Robert , Lee Ryan K , Nelson Thomas R , Schindera Sebastian , Seibert Anthony , Starkey Jay , Suntharalingam Saravanabavaan , Wetter Axel , Wildberger Joachim E , Miglioretti Diana L 
Published: January 2019

Abstract

Objective
To determine patient, institution, and machine characteristics that contribute to variation in radiation doses used for computed tomography (CT).

Design
Prospective cohort study.

Setting
Data were assembled and analyzed from the University of California San Francisco CT International Dose Registry.

Participants
Standardized data from over 2.0 million CT examinations of adults who underwent CT between November 2015 and August 2017 from 151 institutions, across seven countries (Switzerland, Netherlands, Germany, United Kingdom, United States, Israel, and Japan).

Main outcome measures
Mean effective doses and proportions of high dose examinations for abdomen, chest, combined chest and abdomen, and head CT were determined by patient characteristics (sex, age, and size), type of institution (trauma center, care provision 24 hours per day and seven days per week, academic, private), institutional practice volume, machine factors (manufacturer, model), country, and how scanners were used, before and after adjustment for patient characteristics, using hierarchical linear and logistic regression. High dose examinations were defined as CT scans with doses above the 75th percentile defined during a baseline period.

Results
The mean effective dose and proportion of high dose examinations varied substantially across institutions. The doses varied modestly (10-30%) by type of institution and machine characteristics after adjusting for patient characteristics. By contrast, even after adjusting for patient characteristics, wide variations in radiation doses across countries persisted, with a fourfold range in mean effective dose for abdomen CT examinations (7.0-25.7 mSv) and a 17-fold range in proportion of high dose examinations (4-69%). Similar variation across countries was observed for chest (mean effective dose 1.7-6.4 mSv, proportion of high dose examinations 1-26%) and combined chest and abdomen CT (10.0-37.9 mSv, 2-78%). Doses for head CT varied less (1.4-1.9 mSv, 8-27%). In multivariable models, the dose variation across countries was primarily attributable to institutional decisions regarding technical parameters (that is, how the scanners were used).

Conclusions
CT protocols and radiation doses vary greatly across countries and are primarily attributable to local choices regarding technical parameters, rather than patient, institution, or machine characteristics. These findings suggest that the optimization of doses to a consistent standard should be possible.

Study registration

Clinicaltrials.gov
NCT03000751
.
Relation betweenChlamydia trachomatisinfection and pelvic inflammatory disease, ectopic pregnancy and tubal factor infertility in a Dutch cohort of women previously tested for chlamydia in a chlamydia screening trial
Authors: Hoenderboom Bernice M , van Benthem Birgit H B , van Bergen Jan E A M , Dukers-Muijrers Nicole H T M , Götz Hannelore M , Hoebe Christian J P A , Hogewoning Arjan A , Land Jolande A , van der Sande Marianne A B , Morré Servaas A , van den Broek Ingrid V F 
Published: January 2019

ObjectivesA better understanding ofChlamydia trachomatisinfection (chlamydia)–related sequelae can provide a framework for effective chlamydia control strategies. The objective of this study was to estimate risks and risk factors of pelvic inflammatory disease (PID), ectopic pregnancy and tubal factor infertility (TFI) with a follow-up time of up until 8 years in women previously tested for chlamydia in the Chlamydia Screening Implementation study (CSI) and participating in the Netherlands Chlamydia Cohort Study (NECCST).MethodsWomen who participated in the CSI 2008–2011 (n=13 498) were invited in 2015–2016 for NECCST. Chlamydia positive was defined as a positive CSI-PCR test, positive chlamydia serology and/or self-reported infection (time dependent). Data on PID, ectopic pregnancy and TFI were collected by self-completed questionnaires. Incidence rates and HRs were compared between chlamydia-positive and chlamydia-negative women corrected for confounders.ResultsOf 5704 women included, 29.5% (95% CI 28.3 to 30.7) were chlamydia positive. The incidence rate of PID was 1.8 per 1000 person-years (py) (1.6 to 2.2) overall, 4.4 per 1000 py (3.3 to 5.7) among chlamydia positives compared with 1.4 per 1000 py (1.1 to 1.7) for chlamydia negatives. For TFI, this was 0.4 per 1000 py (0.3 to 0.5) overall, 1.3 per 1000 py (0.8 to 2.1) and 0.2 per 1000 py (0.1 to 0.4) among chlamydia positives and negatives, respectively. And for ectopic pregnancy, this was 0.6 per 1000 py (0.5 to 0.8) overall, 0.8 per 1000 py (0.4 to 1.5) and 0.6 per 1000 py (0.4 to 0.8) for chlamydia negatives. Among chlamydia-positive women, the strongest risk factor for PID was symptomatic versus asymptomatic infection (adjusted HR 2.88, 1.4 to 4.5) and for TFI age <20 versus >24 years at first infection (HR 4.35, 1.1 to 16.8).ConclusionWe found a considerably higher risk for PID and TFI in chlamydia-positive women, but the incidence for ectopic pregnancy was comparable between chlamydia-positive and chlamydia-negative women. Overall, the incidence rates of sequelae remained low.Trial registrationNTR-5597.