bluuebunny/crossref_metadata_2025 huggingface dataset:
CEO Entrepreneurial Orientation, Entrenchment, and Firm Value Creation
Authors: Keil Thomas , Maula Markku , Syrigos Evangelos
Published: October 2018

We investigate how CEO entrepreneurial orientation affects firm value creation and how this relationship is moderated by three sources of CEO entrenchment. We conducted a longitudinal analysis of S&P 500 firms between 1999 and 2007, and, in line with our predictions, we found that CEO entrepreneurial orientation enhances firm value creation and that this positive effect is reduced when CEOs are entrenched (1) due to corporate governance provisions that protect them from the majority will of shareholders, (2) due to substantial ownership that provides them too much decision–making power, and (3) because their family has substantial holdings in the corporation.
The Impact of Lack of Clean Cooking Fuels on Sustainable Development in Developing Countries
Authors: Garba Ifeoluwa , Bellingham Richard
Published: October 2018

Access to energy is crucial in tackling many of the current global development challenges that impact on people’s economic, health and social well-being as well as the ability to meet the commitments of reducing carbon emissions through clean energy use. Despite increased attention from multiple governments and agencies, energy poverty remains a serious sustainable development issue in many developing countries. To date, most research have focused on general access to electricity and the generation of clean energy to replace fossil fuels, failing to address the lack of basic access to clean energy for cooking and heating. More people in the world lack access to clean cooking fuels than to electricity. This issue is one aspect of a broader research which investigates the impacts of optimized energy policy and energy business models on sustainable development in developing countries.
Solar Salt Latent Heat Thermal Storage for a Small Solar Organic Rankine Cycle Plant
Authors: Costa Sol-Carolina , Mahkamov Khamid , Kenisarin Murat , Lynn Kevin , Halimic Elvedin , Mullen David
Published: October 2018

The design of the Latent Heat Thermal Storage System (LHTESS) was developed with thermal capacity of about 100 kWh as a part of small solar plant, based on the Organic Rankine Cycle (ORC). The phase change material (PCM) used is Solar salt with the melting/solidification temperature of about 220°C.

Thermo-physical properties of the PCM were measured, including its phase transition temperature, heat of fusion, specific heat and thermal conductivity. The design of the thermal storage was finalized by means of the 3-D CFD analysis.

The thermal storage system is made of six rectangular boxes with dimensions of 1 m (width) × 0.66 m (height) × 0.47 m (depth). The thermal energy is delivered to each of the thermal storage boxes with the use of thermal oil, heated by Fresnel mirrors. The heat is transferred into and from the PCM in the box using 40 bi-directional heat pipes with the external diameter of about 12 mm. The length of the heat pipe in the PCM box is 430 mm and it is placed in the cylindrical metallic protection cartridge, installed in the thermal storage vessel. The working fluid in the heat pipe is water. A set of metallic screens are installed in the box with the pitch of 8–10 mm to enhance the heat transfer from heat pipes to the PCM and vice-versa during the charging and discharging processes, which take about 4 hours.

The one unit of the described thermal storage system is undergoing the laboratory tests. Preliminary results demonstrate that the performance of the thermal storage is in a good agreement with numerical predictions. After completion of final design modifications, all units will be assembled at the plant’s demonstration site and tested with the ORC turbine.
Flow Patterns and Temperature Distribution in an Underground Metro Station
Authors: Hasan Alaa , ElGammal Tarek , Amano Ryoichi S. , Khalil Essam E.
Published: October 2018

Accurate control of thermal conditions in large space buildings like an underground metro station is a significant issue because passengers’ thermal comfort must be maintained at a satisfactory level. The large eddy simulation (LES) model was adopted while using the computational fluid dynamics (CFD) software “STAR CCM+” to set up a CFD station model to predict static air temperature, velocity, relative humidity and predicted mean vote (PMV), which indicates the passengers’ thermal comfort. The increase in the number of passengers using the model station is taken into consideration. The studied cases covered all the possible modes of the station box, these modes are (1) the station box is empty of trains, (2) the presence of one train inside the station box, (3) the presence of two trains inside the station box. The objective is to bring the passengers’ thermal comfort in all modes to the acceptable level. The operation of under platform exhaust (UPE) system is considered in case of train presence inside the station box. The use of UPE is more energy efficient than depending entirely on the air conditioning system to maintain the thermal conditions comfortable.
Additive Manufacturing: A New Paradigm for the Next Generation of High-Power-Density Direct-Drive Electric Generators
Authors: Hayes Austin C. , Sethuraman Latha , Fingersh Lee Jay , Dykes Katherine
Published: October 2018

In recent years, there has been a growing demand for high-power-density direct-drive generators in the wind industry owing to their high reliability, torque per unit volume, and conversion efficiencies. However, direct-drive wind turbine generators are very large, low-speed electric machines, which pose remarkable design and manufacturing issues that challenge their upscaling potential and cost of implementation. With air-gap tolerance as the main design driver, the need for high stiffness shifts the focus toward support-structure design that forms a significant portion of the generator’s total mass. Existing manufacturing processes allow the use of segmented-steel-weldment disk or spoke-arm assemblies that yield stiffer structures per unit mass but tend to be heavier and more expensive to build. As a result, there is a need for a transformative approach to realize lightweight designs that can also facilitate series production at competitive costs. Inspired by recent developments in metal additive manufacturing (AM), we explore a new freedom in the structural design space with a high potential for weight savings in direct-drive generators. This includes the feasibility of using nonconventional complex geometries, such as lattice-based structures as structurally efficient options. Powder-binder jetting of a sand-cast mold was identified as the most feasible AM technology to produce large-scale generator rotor structures with complex geometry. A parametric optimization study was performed and optimized results within deformation and mass constraints were found for each design. The response to the maximum Maxwell stress due to unbalanced magnetic pull was also explored for each design. Further, a topology optimization was applied for each parameter-optimized design to validate results and provide insights into further mass reduction. These novel designs catered for AM are compared in both deflection and mass to conventional rotor designs using NREL’s systems engineering design tool, GeneratorSE. The optimized lattice design with a U-beam truss resulted in a 24% reduction in structural mass of the rotor and 60% reduction in radial deflection. It is demonstrated that additive manufacturing shifts the focus from manufacturability constraints toward lower mass.
Using LIDAR on Wind Turbines for Yaw Error Correction: A Financial Prospective
Authors: Bakhshi Roozbeh , Sandborn Peter
Published: October 2018

Wind energy and especially offshore wind energy faces an uphill battle in the United States to become a mainstream source of energy generation due to its high price relative to fossil fuels. The wind industry is looking for methods to reduce the costs of energy production by improving the efficiency of wind turbines and reducing their operation and maintenance costs. Correction of yaw error is one way to lower the price of wind energy. Yaw error is the angle between the turbine’s central axis in horizontal plane and the wind flow direction. LIDAR devices are used to correct yaw error, however they are expensive. Therefore, there is a need to develop a return on investment model (ROI) to calculate the cost trade-offs of using such systems. This work reviews how yaw error affects the performance and maintenance costs of wind turbines, discuss the development of an ROI model and provide a case study with two scenarios where LIDAR is used to correct the yaw error of an onshore and an offshore wind farm.
Modeling and Experimental Validation of a Pico-Scale Francis Turbine for a Self-Powered Water Disinfection System
Authors: Walsh Rowan W. , Hosseinimanesh Hossein , Nourbakhsh Seyed , Meshkahaldini Mohammad , Bilton Amy M.
Published: October 2018

Access to both electricity and clean drinking water is challenging in many remote communities. A self-powered water disinfection system, currently under development, can potentially address this challenge. In the proposed design, energy from water flowing through the system is harnessed using a pico turbine (nominal output power of 60 W) and used to power an electrochemical disinfection process. The characteristics of turbines at the pico-scale (less than 5kW) required for this system are not well researched, and off-the-shelf designs are either too bulky or too inefficient for this application. This paper presents a model developed to evaluate a new class of efficient pico-scale Francis turbines for this water disinfection system. A computational fluid dynamics (CFD) model of the turbine was developed in ANSYS® CFX® 17.1. The CFD model exploits the rotational symmetry of the turbine and draft tube fluid regions to reduce the computational cost in terms of time and memory. The turbine model is coupled with models of the electric generator and electrochemical cell to determine the balanced operating points. When validated against experimental data, the combined model showed good predictive ability despite its low computational cost: the modeled turbine efficiency is within 5% of the measured values across the operating range of the device. The current turbine design has a hydraulic efficiency above 60 % in its operating range, which is high for a compact turbine at this scale. The combined model was used with a parameterized version of the turbine geometry to identify key performance sensitivities, particularly with the blade trailing edge angle. Turbine efficiency was improved by more than 2 % across the allowable flow rates. The low computational cost of the combined model made it well suited for iterative design optimization, supplanting the need for lengthy experimental trials. Overall, the modeling approach presented here shows good promise for use in picoturbine design.
A Reduced Kinetic Mechanism for Oxy/Methane sCO2 Combustor Simulations
Authors: Manikantachari K. R. V. , Vesely Ladislav , Martin Scott , Bobren-Diaz Jose O. , Vasu Subith
Published: October 2018

Reduced mechanisms are needed for use with computational fluid dynamic codes (CFD) utilized in the design of combustors. Typically, the reduced mechanisms are created from the detailed mechanisms which contain numerous species and reactions that are computationally difficult to handle using most CFD codes. Recently, it has been shown that the detailed Aramco 2.0 mechanism well predicted the available experimental data at high pressures and in high-CO2 diluted methane mixtures. Further, a 23-species gas-phase mechanism is derived from the detailed Aramco 2.0 mechanism by path-flux-analysis method (PFA) by using CHEM-RC. It is identified that the reaction CH4+HO2⇔ CH3+H2O2 is very crucial in predicting the ignition delay times under current conditions. Further, it is inferred that species C2H3 and CH3OH are very important in predicting the ignition delay time of lean sCO2 methane mixtures. Also, the 23-species mechanism presented in this work is performing on par with the detailed Aramco 2.0 mechanism in-terms of simulating ignition delay times, perfectly-stirred-reactor estimates under various CO2 dilutions and equivalence ratios, and prediction of turbulence chemistry interactions. It is observed that the choice of equation-of-state has no significant impact on the ignition delay times of supercritical CH4/O2/CO2 mixtures but it influences supercritical H2/O2/CO2 mixtures considered in this work.
Experimental Study of Swirl Cooling Flow on a Circular Chamber Using 3-D Stereo-PIV
Authors: Galeana Daisy , Beyene Asfaw
Published: October 2018

Experimental study of a swirl flow using 3-D Stereo-PIV (Particle Image Velocimetry) that models a gas turbine blade internal cooling configuration is presented. The work is intended to provide an understanding of the advancements of swirl cooling flow methodology utilizing 3-D Stereo-PIV. The study aims at determining the critical swirl number that has the potential to deliver the maximum heat transfer results. In the swirl cooling flow methodology, cooling air is routed to the turbine blades where it passes through the blade’s internal passages lowering the temperature. An experimental setup with seven discrete tangential jets at three different Reynolds numbers is designed to allow detail measurements of the flow. To provide the particles for velocity measurements an oil particle seeder (LAVision) is used. The circular chamber is made of clear acrylic to allow visualization of the flow phenomena. Data is post-processed in DaVis, velocity calculations are conducted in MATLAB, and TechPlot is used for data visualization. This investigation focuses on the continuous swirl flow that must be maintained via continuous injection of tangential flow, where swirl flow is generated with seven inlets and decays with downstream distance. It was also determined that the critical swirl number, Sn, depends greatly on the location and size of the tangential slots.
CFD Analysis of a Water Flume Design for Testing Marine and Hydrokinetics Energy Converters
Authors: Subramanian Akshith , Goudarzi Navid
Published: October 2018

Marine and hydrokinetic (MHK) energy resources with advantages such as predictability and less variability compared to other forms of renewable energies, have been drawing more interest in recent years. One important phase before commercialization of new MHK technologies is to conduct experimental testing and evaluate their performance in a real environment. In this work, a numerical computational fluid dynamics (CFD) method is used to study the fluid flow behavior within a designed water flume for MHK energy technologies. The water flume design parameters were given by the team collaborators at National Renewable Energy Laboratory (NREL) and Colorado School of Mines. The results from this simulation showed the flow characteristics within the test-section of the proposed water flume design. These results can be used for the follow on phases of this research that includes testing scaled MHK prototypes at different flow rates as well as optimizing either the water flume design to obtain more realistic flow characteristics within the test section or the MHK devices to obtain higher performance metrics at lower cost.
Simulation and Analysis of the Supercritical ORC Heat Exchanger
Authors: Li Yung-Ming , Wang Chi-Chuan
Published: October 2018

The traditional organic Rankine cycle (ORC) is operated below critical point. However, the specific heat of the working fluid undergoes tremendous change near the critical point. This can improve the thermal performance of the system due to the enhancement of heat transfer coefficient within the heat exchanger. However, the strong temperature dependence of thermo-physical properties of the working fluid especially at near the critical point requires much more efforts in designing a heat exchanger. Hence, more elaborate calculation involving stepwise integration is needed as far as accuracy is concerned. Therefore the heat exchanger is divided into several segments. The outlet temperatures of the first segment serve as the input parameters for the second segment, and the process is carried out further on. The fluid properties are calculated with the actual bulk temperature of each segment. With increasing number of segments, better resolution of temperature distribution of both heat source and working fluid within the heat exchanger is achieved. In the present study, a plate heat exchanger was numerically examined by using R-245fa as a working fluid at a supercritical condition. The effects of the working pressure and mass flow rate were examined in detail. For all cases in this study, the maximum of the total heat transfer rate was achieved by a working pressure of 3700 kPa, especially close to critical pressure. It is found that at a working pressure of 4000 kPa and mass flow rate ranging from 1 kg/s to 1.75 kg/s, the total heat transfer rate was independent of the mass flow rate.
The Impact of Preferential Vaporization on Lean Blowout in a Referee Combustor at Figure of Merit Conditions
Authors: Bell David C. , Heyne Joshua S. , Won Sang Hee , Dryer Frederick L.
Published: October 2018

As alternative jet fuels continue to be developed, their impact on combustor performance remains of utmost importance. Alternative jet fuels generally contain few aromatics and differ in alkylated compositions, yielding different chemical and physical properties from those of conventional jet fuels; understanding how these property differences impact combustor performance near limiting conditions is important in certifying their use in blending with petroleum derived fuels or as complete substitutes. Ignition and extinction properties that are associated with Lean Blowout (LBO) are areas of focus for jet fuel certification as they are important safety metrics bounding combustor stability. Previous results for 23 different test fuels in a referee combustor show a strong correlation of Lean Blowout (LBO) with fuel Derived Cetane Number (DCN). This previous study involved fuels with compositions similar to conventional fuels. However, fuels with properties differing significantly from conventional fuels were found to have a weaker correlation with DCN and higher LBO equivalence ratios overall. The surrogate fuels and blends that show the largest discrepancy from the earlier correlation were blends involving highly volatile, low DCN components such as iso-octane prevalent in the early stages of distillation, and less volatile, high DCN normal alkane components such as n-hexadecane, prevalent in the final stages of distillation. Thus, significant differences in fuel reactivity along the distillation curve from those of conventional petroleum derived fuels appeared to exhibit differing LBO character. From these observations, three hypotheses, preferential vaporization, relative droplet lifetimes, and thermal quenching, are proposed and investigated by utilizing the available data. Using normalized power law regressions, distillation simulation methods and Quantitative Structure Property Relation (QSPR) results, the DCN at 34% distillation recovery show a stronger correlation with LBO than the DCN determine for the fuel itself. In this paper, we apply findings to propose fuel compositions to investigate the noted hypotheses by utilizing reactive low molecular weight molecules and a less reactive high molecular weight fuel. The suggested fuel to stress test this hypothesis is a blend of 30 (molar)% n-heptane and 70 (molar)% Gevo Alcohol-to-Jet (ATJ), which is essentially composed of (primarily) 2,2,4,6,6 iso-dodecane and isocetane. If preferential vaporization is significant, then this fuel should be more stable than the “DCN-Law,” i.e. fuels are no more stable than the corresponding DCN allows, would predict.
Compact Cryo-Adsorbent Hydrogen Storage Systems for Fuel Cell Vehicles
Authors: Tamburello David , Hardy Bruce , Sulic Martin , Kesterson Matthew , Corgnale Claudio , Anton Donald
Published: October 2018

Numerical models for the evaluation of cryo-adsorbent based hydrogen storage systems for fuel cell vehicles were developed and validated against experimental data. These models simultaneously solve the conservation equations for heat, mass, and momentum together with the equations for the adsorbent thermodynamics. The models also use real gas thermodynamic properties for hydrogen. Model predictions were compared to data for charging and discharging both MOF-5™ and activated carbon systems. Applications of the model include detailed finite element analysis simulations as well as full vehicle-level system analyses. The present work provides an overview of the compacted adsorbent MOF-5™ storage prototype system, as well as a detailed computational analysis and its validation using 2-liter prototype test system. The results of these validated computational analyses are then projected to a full scale vehicle system, based on an 80 KW fuel cell with a 20 kW battery.

This work is part of the Hydrogen Storage Engineering Center of Excellence (HSECoE), which brings materials development and hydrogen storage technology efforts address onboard hydrogen storage in light duty vehicle applications. The HSECoE spans the design space of the vehicle requirements, balance of plant requirements, storage system components, and materials engineering. Theoretical, computational, and experimental efforts are combined to evaluate, design, analyze, and scale potential hydrogen storage systems and their supporting components against the Department of Energy (DOE) 2020 and Ultimate Technical Targets for Hydrogen Storage Systems for Light Duty Vehicles.
Modeling and Simulation of a Solid Waste Incineration Sustainable Energy System
Authors: Muñoz Matias N. , Vargas José V. C. , Balmant Wellington , Ordóñez Juan C. , Mariano Andre B.
Published: October 2018

Urban solid waste generation has drastically grown around the world, requiring creative, ecologically correct and sustainable solutions to be developed. This work considers a problem of thermodynamic optimization of extracting the most energy from a stream of hot exhaust produced by urban solid waste incineration, considering a stoichiometric combustion model, when the contact heat transfer area is fixed. For that, a mathematical model is introduced to evaluate the rate of heat generation due to the waste incineration process, and the exergetic (power) rate captured by a heat recovery steam generator (heat exchanger). The numerical results show that when the (cold) receiving stream boils in the counterflow heat exchanger; the thermodynamic optimization consists of locating the optimal capacity rate of the cold current. At the optimum, the cold side of the heat transfer surface is divided into three sections: preheating of liquid, boiling and superheating of steam. Experimental results are in good qualitative and quantitative agreement with the numerically calculated mathematical model results. Microalgae cultivated in large-scale vertical tubular compact photobiorreactors are investigated to treat the emissions produced by the incineration, and to increase the efficiency of the global system via cogeneration of co-products with high aggregated commercial value.
Techno-Economic Comparison Between Conventional and Innovative Combined Solar Thermal Power and Desalination Methods for Cogeneration
Authors: Haynes Megan W. , Gunawan Andrey , Yee Shannon K.
Published: October 2018

The U.S. Department of Energy (DOE) has determined that solar power coupled desalination could be the next step in helping to resolve the water-energy nexus. For many decades, integration of concentrating solar power (CSP) electricity generation for combined power and water production has typically utilized the conventional method of steam Rankine cycles. Current research focuses on an enticing innovative method which combines CSP with Brayton cycles and uses supercritical CO2 (sCO2) as a working fluid, allowing for a broader temperature range. This techno-economic study analyzes the power and possible freshwater generation of each cycle and provides a comparison of the techno-economic advantages associated with each technology when applied to desalination processes. The results of this study suggest that recompression-closed Brayton (RCBR) cycle is likely to have the most significant impact in decreasing the levelized cost of electricity (LCOE), almost halving it from combining CSP with the traditional Rankine cycle. Also, to minimize levelized cost of water (LCOW) a smaller scale desalination facility which utilizes multi-effect distillation with thermal vapor compression (MED/TVC) instead of multi-stage flash distillation (MSF) is most applicable. Although the lowest LCOE values are for wet-cooled RCBR with MSF and MED/TVC, in areas where freshwater generation is crucial to be optimized there is only a 0.04 cents/kWh increase for dry-cooled RCBR with MED/TVC to a cost of 9.8 cents/kWh. This suggests the best candidate for optimizing freshwater generation while minimizing both LCOW and LCOE is dry-cooled RCBR with MED/TVC desalination.
Field emission from diamond nanotips for scanning probe lithography
Authors: Hofmann Martin , Lenk Claudia , Ivanov Tzvetan , Rangelow Ivo W. , Reum Alexander , Ahmad Ahmad , Holz Mathias , Manske Eberhard
Published: October 2018

Single-digit nanometer lithography is a basic requirement for beyond CMOS devices. To address this lithography challenge, a variety of different lithographic methods were developed. Here, the authors present the possibility of field emission scanning probe lithography (FE-SPL) with a diamond tip in order to enhance the lifetime of the used tip. A superior mechanical hardness and a good electron emission stability even after a total of 48 h of lithographic patterning by FE-SPL were proven, and features with half pitches down to 15 nm have been fabricated.
Cancer immunotherapy sweeps Nobel for medicine
Authors: Kaiser Jocelyn , Couzin-Frankel Jennifer
Published: October 2018

Prize goes to discoveries that unleash immune system.
Glacial lake outburst floods as drivers of fluvial erosion in the Himalaya
Authors: Cook Kristen L. , Andermann Christoff , Gimbert Florent , Adhikari Basanta Raj , Hovius Niels
Published: October 2018

A sudden outburst of erosion

Glacial lake outburst floods (GLOFs) are exactly what they sound like. The sudden emptying of a glacial lake in high-topography regions like the Himalaya can quickly destroy everything in its path. Cook
et al.
intercepted a GLOF in the Bhotekoshi and Sunkoshi river valleys in central Nepal as they were monitoring the region in the aftermath of the 2015 Gorkha earthquake. They found that a massive amount of erosion occurred during the outburst flood, which suggests that GLOFs may be the primary factor in landscape evolution for these regions.

Science
, this issue p.
53
Junk food, junk science?
Unsavory Truth
Marion Nestle
Basic Books, 2018. 320 pp.
Authors: James Cyan
Published: October 2018

A nutrition expert aims a critical eye at the research and marketing practices of food companies
Smoothening out the patches
Authors: Sommer Anselm , Lemmon Mark A.
Published: October 2018

New roles are discovered for cholesterol transport in a key developmental signaling pathway
Using Antibodies and Mutants To Localize the Presumptive gH/gL Binding Site on Herpes Simplex Virus gD
Authors: Atanasiu Doina , Saw Wan Ting , Lazear Eric , Whitbeck J. Charles , Cairns Tina M. , Lou Huan , Eisenberg Roselyn J. , Cohen Gary H.
Published: October 2018

Virus entry and cell-cell fusion mediated by HSV require gD, gH/gL, gB, and a gD receptor. Neutralizing antibodies directed against any of these proteins bind to residues within key functional sites and interfere with an essential step in the fusion pathway. Thus, the epitopes of these MAbs identify critical, functional sites on their target proteins. Unlike many anti-gD MAbs, which block binding of gD to a cellular receptor, two, MC2 and MC5, block a separate, downstream step in the fusion pathway which is presumed to be the activation of the modulator of fusion, gH/gL. By combining epitope mapping of a panel of gD mutants with fusion and virus entry assays, we have identified residues that are critical in the binding and function of these two MAbs. This new information helps to define the site of the presumptive interaction of gD with gH/gL, of which we have limited knowledge.
Heart of the matter: reverse takotsubo syndrome in an anthracycline-exposed oncology patient
Authors: Voit Jay , Tibrewala Anjan , Akhter Nausheen
Published: October 2018

A 24-year-old man with acute myelogenous leukaemia and a history of anthracycline treatment is hospitalised for non-anthracycline chemotherapy. He develops new-onset heart failure requiring intesive care unit (ICU) admission during his stay. There is debate as to the aetiology of his heart failure, whether anthracycline cardiotoxicity or takotsubo syndrome. He is diuresed and discharged home with close follow-up. Ultimately, the retrospective use of two-dimensional speckle-tracking echocardiography derived strain helps diagnose reverse takotsubo syndrome.
Socioeconomic position, symptoms of depression and subsequent mental healthcare treatment: a Danish register-based 6-month follow-up study on a population survey
Authors: Packness Aake , Halling Anders , Hastrup Lene Halling , Simonsen Erik , Wehberg Sonja , Waldorff Frans Boch
Published: October 2018

Objective

Examine whether the severity of symptoms of depression was associated with the type of mental healthcare treatment (MHCT) received, independent of socioeconomic position (SEP).

Design

Register-based 6-month follow-up study on participants from the Danish General Suburban Population Study (GESUS) 2010–2013, who scored the Major Depression Inventory (MDI).

Participants

Nineteen thousand and eleven respondents from GESUS.

Interventions

The MHCT of the participants was tracked in national registers 4 months prior and 6 months after their MDI scores. MHCT was graduated in levels. SEP was defined by years of formal postsecondary education and income categorised into three levels. Data were analysed using logistic and Poisson regression analyses.

Outcomes

MHCT included number of contacts with: general practitioner (GP), GP mental health counselling, psychologist, psychiatrist, emergency contacts, admissions to psychiatric hospitals and prescriptions of antidepressants.

Results

For 547 respondents with moderate to severe symptoms of depression there was no difference across SEP in use of services, contact (y/n), frequency of contact or level of treatment, except respondents with low SEP had more frequent contact with their GP. However, of the 547 respondents , 10% had no treatment contacts at all, and 47% had no treatment beyond GP consultation. Among respondents with no/few symptoms of depression, postsecondary education ≥3 years was associated with more contact with specialised services (adjusted OR (aOR) 1.92; 95% CI 1.18 to 3.13); however, this difference did not apply for income; additionally, high SEP was associated with fewer prescriptions of antidepressants (education aOR 0.69; CI 0.50 to 0.95; income aOR 0.56, CI 0.39 to 0.80) compared with low SEP.

Conclusion

Participants with symptoms of depression were treated according to the severity of their symptoms, independent of SEP; however, more than half with moderate to severe symptoms received no treatment beyond GP consultation. People in low SEP and no/few symptoms of depression were more often treated with antidepressants. The study was approved by The Danish Data Protection Agency Journal number 2015-41-3984. Accessible at:https://www.datatilsynet.dk/fortegnelsen/soeg-i-fortegnelsen/
Development of a risk predictive scoring system to identify patients at risk of representation to emergency department: a retrospective population-based analysis in Australia
Authors: Ahn Euijoon , Kim Jinman , Rahman Khairunnessa , Baldacchino Tanya , Baird Christine
Published: October 2018

Objective

To examine the characteristics of frequent visitors (FVs) to emergency departments (EDs) and develop a predictive model to identify those with high risk of a future representations to ED among younger and general population (aged ≤70 years).

Design and setting

A retrospective analysis of ED data targeting younger and general patients (aged ≤70 years) were collected between 1 January 2009 and 30 June 2016 from a public hospital in Australia.

Participants

A total of 343 014 ED presentations were identified from 170 134 individual patients.

Main outcome measures

Proportion of FVs (those attending four or more times annually), demographic characteristics (age, sex, indigenous and marital status), mode of separation (eg, admitted to ward), triage categories, time of arrival to ED, referral on departure and clinical conditions. Statistical estimates using a mixed-effects model to develop a risk predictive scoring system.

Results

The FVs were characterised by young adulthood (32.53%) to late-middle (26.07%) aged patients with a higher proportion of indigenous (5.7%) and mental health-related presentations (10.92%). They were also more likely to arrive by ambulance (36.95%) and leave at own risk without completing their treatments (9.8%). They were also highly associated with socially disadvantage groups such as people who have been divorced, widowed or separated (12.81%). These findings were then used for the development of a predictive model to identify potential FVs. The performance of our derived risk predictive model was favourable with an area under the receiver operating characteristic (ie, C-statistic) of 65.7%.

Conclusion

The development of a demographic and clinical profile of FVs coupled with the use of predictive model can highlight the gaps in interventions and identify new opportunities for better health outcome and planning.
Impact of PCSK9 monoclonal antibodies on circulating hs-CRP levels: a systematic review and meta-analysis of randomised controlled trials
Authors: Cao Ye-Xuan , Li Sha , Liu Hui-Hui , Li Jian-Jun
Published: October 2018

Objective

To evaluate the potential effects of proprotein convertase subtilisin/kexin type 9 monoclonal antibody (PCSK9-mAb) on high-sensitivity C reactive protein (hs-CRP) concentrations.

Design

A systematic review and meta-analysis of randomised controlled trials.

Data sources

PubMed, MEDLINE, the Cochrane Library databases, ClinicalTrials.gov and recent conferences were searched from inception to May 2018.

Eligibility criteria for selecting studies

All randomised controlled trials that reported changes of hs-CRP were included.

Results

Ten studies involving 4198 participants were identified. PCSK9-mAbs showed a slight efficacy in reducing hs-CRP (−0.04 mg/L, 95% CI: −0.17 to 0.01) which was not statistically different. The results did not altered when subgroup analyses were performed including PCSK9-mAb types (alirocumab: 0.12 mg/L, 95% CI: −0.18 to 0.43; evolocumab: 0.00 mg/L, 95% CI: −0.07 to 0.07; LY3015014: −0.48 mg/L, 95% CI: −1.28 to 0.32; RG7652: 0.35 mg/L, 95% CI: −0.26 to 0.96), treatment duration (≤12w: 0.00 mg/L, 95% CI: −0.07 to 0.07; >12w: −0.11 mg/L, 95% CI: −0.45 to −0.23), participant characteristics (familial hypercholesterolaemia: 0.00 mg/L, 95% CI: −0.07 to 0.07; non-familial hypercholesterolaemia: 0.07 mg/L, 95% CI: −0.12 to 0.26; mix: −0.48 mg/L, 95% CI: −1.28 to 0.32) and treatment methods (monotherapy: 0.00 mg/L, −0.08 to 0.07; combination therapy: −0.08 mg/L, −0.37 to 0.21). Meta-regression analyses suggested no significant linear correlation between baseline age (p=0.673), sex (p=0.645) and low-density lipoprotein cholesterol reduction (p=0.339).

Conclusions

Our updated meta-analysis suggested that PCSK9-mAbs had no significant impact on circulating hs-CRP levels irrespective of PCSK9-mAb types, participant characteristics and treatment duration or methods.
Study protocol for an observational register-based study on health and risk factors in patients with hip and knee osteoarthritis
Authors: Gustafsson Kristin , Rolfson Ola , Eriksson Marit , Dahlberg Leif , Kvist Joanna
Published: October 2018

Introduction

Hip and knee osteoarthritis is a leading cause of disability worldwide. Currently, the course of deterioration in pain and physical functioning in individuals with osteoarthritis is difficult to predict. Factors such as socioeconomic status and comorbidity contribute to progression of osteoarthritis, but clear associations have not been established. There is a need for early identification of individuals with slow disease development and a good prognosis, and those that should be recommended for future joint replacement surgery.

Methods and analysis

This nationwide register-based study will use data for approximately 75 000 patients who sought and received core treatment for osteoarthritis in primary healthcare, and were registered in the Swedish population-based National Quality Register for Better Management of Patients with Osteoarthritis. These data will be merged with data for replacement surgery, socioeconomic factors, healthcare consumption and comorbidity from the Swedish Hip Arthroplasty Register, the Swedish Knee Arthroplasty Register, Statistics Sweden and the National Board of Health and Welfare, Sweden. The linkage will be performed using personal identity numbers that are unique to all citizens in Sweden.

Ethics and dissemination

The study was approved by the Regional Ethical Review Board in Gothenburg, Sweden (dnr 1059–16). The results from this study will be submitted to peer-reviewed journals and reported at suitable national and international meetings.

Trial registration number

NCT03438630.
Research priorities in fragility fractures of the lower limb and pelvis: a UK priority setting partnership with the James Lind Alliance
Authors: Fernandez Miguel A , Arnel Laura , Gould Jenny , McGibbon Alwin , Grant Richard , Bell Philip , White Stuart , Baxter Mark , Griffin Xavier , Chesser Tim , Keene David , Kearney Rebecca S , White Catherine , Costa Matthew L
Published: October 2018

Objective

To determine research priorities in fragility fractures of the lower limb and pelvis which represent the shared priorities of patients, their friends and families, carers and healthcare professionals.

Design/setting

A national (UK) research priority setting partnership.

Participants

Patients over 60 years of age who have experienced a fragility fracture of the lower limb or pelvis; carers involved in their care (both in and out of hospital); family and friends of patients; healthcare professionals involved in the treatment of these patients including but not limited to surgeons, anaesthetists, paramedics, nurses, general practitioners, physicians, physiotherapists and occupational therapists.

Methods

Using a multiphase methodology in partnership with the James Lind Alliance over 18 months (August 2016–January 2018), a national scoping survey asked respondents to submit their research uncertainties. These were amalgamated into a smaller number of research questions. The existing evidence was searched to ensure that the questions had not been answered. A second national survey asked respondents to prioritise the research questions. A final shortlist of 25 questions was taken to a multistakeholder workshop where a consensus was reached on the top 10 priorities.

Results

There were 963 original uncertainties submitted by 365 respondents to the first survey. These original uncertainties were refined into 88 research questions of which 76 were judged to be true uncertainties following a review of the research evidence. Healthcare professionals and other stakeholders (patients, carers, friends and families) were represented equally in the responses. The top 10 represent uncertainties in rehabilitation, pain management, anaesthesia and surgery.

Conclusions

We report the top 10 UK research priorities in patients with fragility fractures of the lower limb and pelvis. The priorities highlight uncertainties in rehabilitation, postoperative physiotherapy, pain, weight-bearing, infection and thromboprophylaxis. The challenge now is to refine and deliver answers to these research priorities.
Caesarean section provision and readiness in Tanzania: analysis of cross-sectional surveys of women and health facilities over time
Authors: Cavallaro Francesca L , Pembe Andrea B , Campbell Oona , Hanson Claudia , Tripathi Vandana , Wong Kerry LM , Radovich Emma , Benova Lenka
Published: October 2018

Objectives

To describe trends in caesarean sections and facilities performing caesareans over time in Tanzania and examine the readiness of such facilities in terms of infrastructure, equipment and staffing.

Design

Nationally representative, repeated cross-sectional surveys of women and health facilities.

Setting

Tanzania.

Participants

Women of reproductive age and health facility staff.

Main outcome measures

Population-based caesarean rate, absolute annual number of caesareans, percentage of facilities reporting to perform caesareans and three readiness indicators for safe caesarean care: availability of consistent electricity, 24 hour schedule for caesarean and anaesthesia providers, and availability of all general anaesthesia equipment.

Results

The caesarean rate in Tanzania increased threefold from 2% in 1996 to 6% in 2015–16, while the total number of births increased by 60%. As a result, the absolute number of caesareans increased almost fivefold to 120 000 caesareans per year. The main mechanism sustaining the increase in caesareans was the doubling of median caesarean volume among public hospitals, from 17 caesareans per month in 2006 to 35 in 2014–15. The number of facilities performing caesareans increased only modestly over the same period. Less than half (43%) of caesareans in Tanzania in 2014–15 were performed in facilities meeting the three readiness indicators. Consistent electricity was widely available, and 24 hour schedules for caesarean and (less systematically) anaesthesia providers were observed in most facilities; however, the availability of all general anaesthesia equipment was the least commonly reported indicator, present in only 44% of all facilities (34% of public hospitals).

Conclusions

Given the rising trend in numbers of caesareans, urgent improvements in the availability of general anaesthesia equipment and trained anaesthesia staff should be made to ensure the safety of caesareans. Initial efforts should focus on improving anaesthesia provision in public and faith-based organisation hospitals, which together perform more than 90% of all caesareans in Tanzania.
Real-world evidence for postgraduate students and professionals in healthcare: protocol for the design of a blended massive open online course
Authors: Meinert Edward , Alturkistani Abrar , Car Josip , Carter Alison , Wells Glenn , Brindley David
Published: October 2018

Introduction

There is an increased need for improving data science skills of healthcare professionals. Massive open online courses (MOOCs) provide the opportunity to train professionals in a sustainable and cost-effective way. We present a protocol for the design and development of a blended MOOC on real-world evidence (RWE) aimed at improving RWE data science skills. The primary objective is to provide the opportunity to understand the fundamentals of RWE data science and to implement methods for analysing RWD. The blended format of MOOC will combine the expertise of healthcare professionals joining the course online with the on-campus students. We expect learners to take skills taught in MOOC and use them to seek new employment or to explore entpreneurship activities in these domains.

Methods and analysis

The proposed MOOC will be developed through a blended format using the Analysis, Design, Development, Implementation and Evaluation instructional design model and following the connectivist–heutagogical learning theories (as a hybrid MOOC). The target learners will include postgraduate students and professionals working in the health-related roles with interest in data science. An evaluation of MOOC will be performed to assess MOOCs success in meeting its intended outcomes and to improve future iterations of the course.

Ethics and dissemination

The education course design protocol was approved by EIT Health (grant 18654) as part of the EIT Health CAMPUS Deferred Call for Innovative Education 2018. Results will be published in a peer-reviewed journal.
Qualitative protocol for understanding the contribution of Australian policy in the urban planning, justice, energy and environment sectors to promoting health and health equity
Authors: Baum Fran , Delany-Crowe Toni , Fisher Matthew , MacDougall Colin , Harris Patrick , McDermott Dennis , Marinova Dora
Published: October 2018

Introduction

A well-established body of literature demonstrates that health and equity are strongly influenced by the consequences of governments’ policy and resultant actions (or inactions) outside the health sector. Consequently, the United Nations, and its agency the WHO, have called for national leadership and whole-of-government action to understand and address the health impacts of policies inallsectors. This research responds to that call by investigating how policymaking in four sectors—urban planning, justice, energy and environment—may influence the social determinants of health and health equity (SDH/HE).

Methods and analysis

The research design is informed by a critical qualitative approach. Three successive stages are included in the design. The first involves analysing all strategic policy documents and selected legislative documents from the four sectors (n=583). The document analysis is based on a coding framework developed to identify alignment between the documents and the SDH/HE. Two policies that demonstrate good practice in regard to SDH/HE will be selected from each sector during the second stage for embedded case study analysis (total n=8). This is intended to illuminate which factors have supported recognition and action on SDH/HE in the selected policies. The third stage involves progressive theoretical integration and development to understand political and institutional facilitators and barriers to action on SDH/HE, both within and between sectors.

Ethics and dissemination

The research will provide much needed evidence about how coherent whole-of-government action on SDH/HE can be advanced and contribute knowledge about how health-enhancing policy activity in the four sectors may be optimised. Learnings from the research will be shared via a project advisory group, policy briefings, academic papers, conference presentations and research symposia. Ethics approval has been secured for the embedded case studies, which involve research participants.
Postpartum quality improvement strategy for increasing long-acting contraception uptake at a University Hospital in Haiti
Authors: Casella Jean-Baptiste Meredith , Louis Stephanie , Millien Christophe , Jeune Erwine Dina , Sainterant Ornella , Joseph Jean Paul
Published: October 2018

To address the gap in the uptake of long-acting contraception (LAC) methods among high-risk postpartum women who fail to return for a family planning method at HôpitalUniversitaire de Mirebalais in the Central Plateau Department of Haiti, contraceptive implant trainings were held for providers on the Labour and Delivery, Post-Partum and Internal Medicine inpatient wards.

A very high maternal mortality rate affects large numbers of women in Haiti; however, contraceptive use can reduce maternal mortality significantly. A quality improvement strategy to offer LAC methods to immediate postpartum women at a University Hospital in rural Haiti was initiated in March 2016. This new strategy produced an average improvement from 5% to 32% of women delivering at the hospital, accepting a long-acting method (including bilateral tubal ligations) by the end of the project and which has proved sustainable at an average of 20% to date.