bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Investigation of a Simplified Model of a Transformer Cooling System
Authors: Lokhmanets Iurii , Baliga B. Rabi
Published: September 2017

An experimental investigation of a scaled-down and simplified laboratory model of a transformer cooling system is presented and discussed in this paper. The overall goal of this work was to obtain experimental data for validating cost-effective approximate mathematical models, used in investigations aimed at the development of numerical methods for assessing the operating limits of current transformers and optimizing the designs of next-generation transformers. The laboratory model used in this work was a vertical, single-phase, closed-loop thermosyphon operating with water as the working fluid. The steady and unsteady behaviors of this closed-loop thermosyphon were established and investigated using the following series of power inputs: 50 W, 125 W, 200 W, 125 W, and 50 W. Each of these levels of power input was maintained until steady-state conditions were achieved; and then the excursion to the adjacent power level (up or down, depending on the position in the aforementioned series) was effected. The corresponding experimental results are presented and discussed in this paper. The steady-state experiments with water as the working fluid are used to obtain valuable benchmarking results and also reliable initial conditions for the unsteady experiments. The experiments with excursions from one power level to an adjacent one provide novel results pertaining to unsteady operation of closed-loop thermosyphons. Another novel feature of this work is a demonstration that a simple lumped-parameter formulation can yield good predictions of the overall unsteady behavior of closed-loop thermosyphon systems akin to those used for cooling transformers.
Determination of the Start and End of Combustion in a Direct Injection Diesel Engine Using the Apparent Heat Release Rate
Authors: Reyes Joseph Gerard T. , Quiros Edwin N.
Published: September 2017

The combustion duration in an internal combustion engine is the period bounded by the engine crank angles known as the start of combustion (SOC) and end of combustion (EOC), respectively. This period is essential in analysis of combustion for the such as the production of exhaust emissions. For compression-ignition engines, such as diesel engines, several approaches were developed in order to approximate the crank angle for the start of combustion. These approaches utilized the curves of measured in-cylinder pressures and determining by inspection the crank angle where the slope is steep following a minimum value, indicating that combustion has begun. These pressure data may also be utilized together with the corresponding cylinder volumes to generate the apparent heat release rate (AHRR), which shows the trend of heat transfer of the gases enclosed in the engine cylinder. The start of combustion is then determined at the point where the value of the AHRR is minimum and followed by a rapid increase in value, whereas the EOC is at the crank angle where the AHRR attains a flat slope prior to the exhaust stroke of the engine. To verify the location of the SOC, injection line pressures and fuel injection timing are also used. This method was applied in an engine test bench using a four-cylinder common-rail direct injection diesel engine with a pressure transducer installed in the first cylinder. Injector line pressures and fuel injector voltage signals per engine cycle were also recorded and plotted. By analyzing the trends of this curves in line with the generated AHRR curves, the SOC may be readily determined.
Numerical Simulation of Methane Hydrate Dissociation in Glass Micro Channels by Depressurization
Authors: Wang Xin , Li Weizhong , Yu Minghao
Published: September 2017

Methane hydrate has been paid considerable attention on how to exploit it by efficient and economical methods. A computer modeling approach was used to obtain more detail information during the process of methane hydrate decomposition. A comprehensive Users’ Defined Subroutine (UDS) was used in the FLUENT code to model the methane hydrate dissociation by depressurization. The kinetic model and equilibrium condition were contained in the UDS. The new UDS can model the heat and mass transfer during the decomposition process of methane hydrate. The behavior of the methane hydrate decomposition process in both laboratory-scale simulation and micro channels simulation was investigated in this paper. The laboratory-scale simulation results were compared with ones of the laboratory-scale system studied by Masuda et al. to verify the UDS. Evolutions of methane gas, water and hydrate in the cross micro channels were obtained. The phenomenon of water freezing was predicted by comparing the water temperature and freezing temperature. The results also showed that the dissociation process of gas hydrates as well as the water freezing phenomenon occur not only in the interface between hydrate layer and production zone, but also deep in the hydrate zone.
Ash Melting Behavior of Blended Coal With Chinese Xinjiang High-Alkali Coal
Authors: Wu Xiaojiang , Zhang Jianwen , Zhang Xiang , Chen Nan , Yan Kai
Published: September 2017

This paper is aimed to clarify the ash deposition/slagging behavior of blended coal with Xinjiang High-Alkali coal (HA coal) during the combustion process in boiler. One typical Xinjiang coal (HA coal) and another low-alkali coal (LA coal) have been mixed to study the ash melting behavior as a function of coal blending ratio, through the use of AFTs test, XRD, SEM-EDX characterization of ash samples and 3MW pilot-scale test. The results indicate that, the trend of AFTs is not linearly related to the blending ratio of coal mixtures. Instead, it is highly linked with the changes on the liquidus temperature from the ternary phase diagram systems. The initial melting temperature of HA coal ash is approximately 275°C lower than that of LA coal ash due to the existence of alkali and alkaline earth metals, although it has relative higher ash fusion temperature. The mixing of LA coal is not only beneficial to reduce the amount of vaporized sodium, but it also increases the initial melting temperature of blended ash due to the physical and chemical reactions between alkali and silica particles. The higher content of Na gas was formed during HA coal combustion process due to the promoted effect of the existence of Cl in HA coal. Some low melting minerals, such as Na2SO4, Na3Fe(SO4), NaS2O7, were found as the dominate minerals in its deposit ash on heat transfer tubes in the temperature range 650∼1000°C when combustion HA coal. When blended with other LA coal, the amount of deposit ash was decreased and the shape of it became looser due to some high melting minerals were found in its deposit ash, such as quartz and mullite etc. The optimum blending ratio of LA coal is 20% for its safe operation for HA coal.
Evacuated Tube Solar Collectors Integrated With Phase Change Materials and Silicone Oil
Authors: Papadimitratos Alexios , Sobhansarbandi Sarvenaz , Pozdin Vladimir , Zakhidov Anvar , Hassanipour Fatemeh
Published: September 2017

This paper presents a novel method of integrating Phase Change Materials (PCMs) and Silicone oil within the Evacuated solar Tube Collectors (ETCs) for application in Solar Water Heaters (SWHs). In this method, heat pipe is immersed inside the phase change material, where heat is effectively accumulated and stored for an extended period of time due to thermal insulation of evacuated tubes. The proposed solar collector utilizes two distinct phase change materials (dual-PCM), namely Tritriacontane paraffin and Erythritol, with melting temperature 72°C and 118°C respectively. The integration of Silicone oil for uniform melting of the PCMs, utilizes the convective heat transfer inside the evacuated tubes, as this liquid polymerized material is well known for its temperature-stability and an excellent heat transfer medium. The operation of solar water heater with the proposed solar collector is investigated during both normal and stagnation (on-demand) operation. The feasibility of this technology is tested via small scale and large scale commercial solar water heaters. Beyond the improved functionality for solar water heater systems, the results from this study show show efficiency improvement of 26% for the normal operation and 66% for the stagnation mode compared with standard solar water heaters that lack phase change materials and silicone oil. The benefit of this method includes improved functionality by delayed release of heat, thus providing hot water during the hours of high demand or when solar intensity is insufficient such in a cloudy day and during night time.
Characterizing Particle-Wall Contact Behavior and Fluctuations in Gravity-Driven Dense Granular Flows in Cylindrical Tubes Using DEM
Authors: Chilamkurti Yesaswi N. , Gould Richard D.
Published: September 2017

The primary objective of the paper is to observe and characterize the flow attributes of gravity-driven dry granular media in vertical cylindrical tubes. Particle packing fractions of ∼60% were the prime focus in the current study as the targeted application is the use of dense particulate media as heat transfer fluids (HTF). Experimental and computational studies were previously conducted to understand the influence of different geometrical parameters on the flow physics [1], [2]. Flowrate, particulate velocity, and packing fraction profiles were studied for different inertial numbers and preliminary observations were made about the corresponding regimes. However, flow characteristics that could have a direct implication on the heat transfer behavior remained unexplored. Hence, the current effort serves as an extension of our previous studies. The three-dimensional computer simulations were conducted by implementing the Discrete Element Method (DEM) for the Lagrangian modelling of particles. Hertz-Mindilin models were used for the soft-particle formulations of inter-particulate contacts. Since the particle contact behavior plays an important role in the conduction heat transfer of these regimes [3], the particle-wall residence times and near-wall packing fractions are studied in the current work. Particle fluctuations, which lead to flow agitation that effect heat transfer [4] are also studied. It was observed that the intermittent nature of the flow resulted in the propagation of wave-like structures in the upstream direction. The characteristics of this phenomenon and its possible influence on the heat transfer physics is also discussed.
Working Fluid Analysis for Supercritical Organic Rankine Cycles for Medium Geothermal Reservoir Temperatures
Authors: Moloney Francesca , Almatrafi Eydhah , Goswami D. Y. , Stefanakos Elias
Published: September 2017

A steady state model of a supercritical organic Rankine cycle (SORC) was created in MATLAB and validated. Fluid properties were obtained using NIST REFPROP. Various working fluids were tested, including pentane (R601), isopentane (R601a), butane (R600), isobutane (R600a), butene, and cis-butene. Pentane and isopentane have not been of focus for SORCS at these temperatures. Varying turbine inlet temperatures ranging from 170 to 240°C were tested with the heat source provided by a medium temperature geothermal reservoir. A parametric analysis was performed on varying inlet pressure and turbine inlet temperature in comparison to first law efficiency, second law efficiency, effectiveness, and net work produced to analyze the overall and exergetic performance of each fluid. Optimum first law efficiency ranged from 17 to 22%. Cis-butene and pentane performed the best in all performance factors analyzed. Pentane and isopentane performed the best at pressures near or below their critical point. It was also found that near the critical temperature, a subcritical ORC has better performance than an SORC. This study is beneficial for not only geothermal energy but for applications that can provide operating temperatures between 170 to 240°C.
Wind Effects on Air-Cooled Condensers: Wind-Tunnel 2-D Flow Fields for Base Case, Wind Screens, and Louvers
Authors: Parker Ryan S.
Published: September 2017

Detailed 2-axis hot-wire anemometry measurements were conducted around a scale Air-Cooled Condenser (ACC) model within an atmospheric boundary layer wind-tunnel. The measurements were taken for the “standard” flow field, as well as the effects of using partial wind screens and louvers as mitigation measures. This provides a representation of the complex 2-D flow field present underneath an operating ACC when subjected to various speed cross winds.

Optimal ACC operation is achieved when all fans generate a uniform flow pattern into the plenum chamber of the ACC, and this is dependent on the speed and direction of the air at the inlet. The wind-tunnel measurements support the assertion that wind screens reduce the horizontal wind speed directly downstream; however, this comes with a marked increase in turbulence. The results suggest a wind-screen covering a smaller portion (6% tested) of the ACC inlet may be more beneficial than the more common 50% coverage.
Experimental and Numerical Investigation of Vibration Damping Using a Thin Layer Coating
Authors: Aziz Imran , Hussain Sajjad , Tarar Wasim , Akhtar Imran
Published: September 2017

High cycle fatigue (HCF) is the main cause of failure in rotating machinery especially in aircraft engines which results in the loss of human life as well as billions of dollars. More than 60 percent of aircraft accidents are related to High cycle fatigue. Major reason for HCF is vibratory stresses induced in the blades at resonance. Damping is needed to avoid vibratory stresses to reach the failure level. High speed rotating machinery has to pass through the resonance in order to reach the operational speed and chances of failure are high at resonance level. It is therefore required to suppress the vibrations at resonance level to avoid any damage to the structure. Application of coating to suppress vibrations is a current area of research. Various types of coatings have been studied recently. This includes plasma graded coatings, viscoelastic dampers, piezoelectric material damping, and magnetomechanical damping. In this research, the phenomenon of damping using a coating of nickel alloy on a steel beam is studied experimentally and numerically to reduce vibratory stresses by enhancing damping characteristics to avoid aircraft engine and rotating machinery failure. For this purpose, uncoated and nickel alloy coated steel beams are fabricated. The coating procedure was performed using plasma arc method. The beams were then mounted in a cantilevered position and bump and vibration shaker tests were conducted to determine the natural frequencies and mode shapes. One of the most important parameter to measure the damping of a system is the damping ratio. In order to determine the damping ratio, vibration analyzer mode was adjusted in time domain and beam was excited by using a hammer. The vibration analyzer showed the vibration decay as a function of time. Using that decay, damping ratio was calculated by using logarithmic decrement method. In order to investigate and compare the damping characteristics of un-coated and coated beams, forced response method was employed. In this method, beams were excited at 1st and 2nd bending mode natural frequencies using vibration shaker. Results were very encouraging and showed a significant improvement in damping characteristics. The experimental results were then endorsed by numerical results which were achieved by performing modal and forced response analysis using finite element analysis techniques.
Demonstration Test of Wood Pellet Co-Firing for Pulverized Coal Fired Boiler
Authors: Ishii Hiroki , Nariai Kentaro , Inoue Daisuke , Fukushima Hitoshi , Kasai Hidekazu , Ohno Emi
Published: September 2017

Global warming is one of the most important topics in power generation field. Wood pellet is carbon neutral fuel and it is expected to reduce CO2 emission from fossil fuel. Recently in Japan, wood pellet is already utilized in many pulverized coal fired boilers in a limited range of a few percent. For the further CO2 emission reduction, high co-firing ratio of wood pellet is expected. The firing system of wood pellet is required to be separated from the coal firing system in the view point of technique, and it is desired to slightly modify the existing coal firing system from the view point of dissemination. IHI developed a wood pellet mill which equipped some devices to the coal mill. By modifying one coal mill in a commercial power plant to the pellet mill, grinding wood pellet was succeeded, and co-firing rate of 25 % was achieved. This paper shows the economic and technical evaluations of wood pellet utilization in coal fired power plant including the impact of lumbering to the forest.
Effect of Oxygen Injection on Hydrogen Sulfide Pyrolysis
Authors: El-Melih A. M. , Al Shoaibi A. , Gupta A. K.
Published: September 2017

Pyrolysis of hydrogen sulfide, as an alternative treatment method to Claus process, with simultaneous hydrogen production and sulfur recovery is an energy intensive process. The high energy demand of the process remains a hindrance to its application. Production of hydrogen via hydrogen sulfide oxidation at very high equivalence ratios, compared to the high equivalence ratio of 3 employed in Claus reactor, has been studied experimentally. The objective of this approach is to alleviate the energy load requirement of hydrogen production from hydrogen sulfide stream. Since combustion of hydrogen sulfide cannot be sustained at such high equivalence ratios, partial oxidation reaction was examined in a heated quartz tubular reactor that was placed inside an electrical furnace. Oxygen concentration of 1% or 2 % in 10% H2S (called the 10%H2S/O2 mixture) were injected into the reactor with the remaining 90% nitrogen gas. These results were compared to the case of decomposing H2S alone. Experimental data showed that destruction of hydrogen sulfide increased with oxygen injection and that it increased with increase in oxygen concentration. Injection of oxygen at increased concentration consumed hydrogen constituent in hydrogen sulfide to water to result in dramatic decrease in hydrogen production. Formation of sulfur dioxide was absent over the examined temperature range of 1273–1673 K. These results provide the potential of hydrogen production from hydrogen sulfide oxidation, define the favorable operational conditions and outline the potential future developments for treatment of hydrogen sulfide.
Spherical wave scattering from rough surfaces and array processing: Application to sound-speed profile measurement uncertainty analysis
Authors: Pinson Samuel
Published: September 2017

A three-dimensional modeling of spherical wave reflection on layered media with rough interfaces is used to study the roughness influence in sediment sound-speed profile measurements. The configuration of the numerical experiment consists of a point source and a horizontal array of hydrophones. In addition, theoretical uncertainties on the angle of arrival and travel time of a spherical wave reflected over a slightly rough interface are derived by including the array processing in the Helmholtz-Kirchhoff integral. The sound-speed profile sensitivity to those parameters is used to compare theory and numerical experiments. The agreement is good and shows a surprisingly strong influence of the roughness on the sound-speed profile measurement.
Translational illusion of acoustic sources by transformation acoustics
Authors: Sun Fei , Li Shichao , He Sailing
Published: September 2017

An acoustic illusion of creating a translated acoustic source is designed by utilizing transformation acoustics. An acoustic source shifter (ASS) composed of layered acoustic metamaterials is designed to achieve such an illusion. A practical example where the ASS is made with naturally available materials is also given. Numerical simulations verify the performance of the proposed device. The designed ASS may have some applications in, e.g., anti-sonar detection.
Resistance Training Combined With Diet Decreases Body Fat While Preserving Lean Mass Independent of Resting Metabolic Rate: A Randomized Trial
Authors: Miller Todd , Mull Stephanie , Aragon Alan Albert , Krieger James , Schoenfeld Brad Jon
Published: September 2017

The purpose of this study was to determine the effects of resistance training only (RT; n = 10), dietary intervention only (DIET; n = 10), resistance training plus diet (RT+DIET; n = 10), and control (CON; n = 10) on body composition and resting metabolic rate (RMR) in a cohort of 40 premenopausal female volunteers. Subjects in DIET and RT+DIET were provided with daily macronutrient and calorie goals based on DXA and RMR tests, with protein maintained at 3.1 g/kg/day. Subjects in the RT and RT+DIET groups performed a supervised progressive RT program consisting of exercises for all the major muscle groups of the body. Results showed a significant month-by-group interaction for change in fat mass with no significant linear trend for control. The three treatment groups all showed significant linear decreases in fat mass, but the slope of the decrease became progressively steeper from the RT, to DIET, to RT+DIET. A significant linear increase for lean mass was seen for resistance training only. There was a nonsignificant increase in RMR in all groups from Month 0 to Month 4 but no significant month by group interaction. In conclusion, significant reductions in fat mass were achieved by all experimental groups, but results were maximized by RT+DIET. Only the RT group showed significant increases in lean mass.
What Influences Collegiate Coaches’ Intentions to Advance Their Leadership Careers? The Roles of Leader Self-Efficacy and Outcome Expectancies
Authors: Machida-Kosuga Moe , Schaubroeck John M. , Gould Daniel , Ewing Martha , Feltz Deborah L.
Published: September 2017

The purpose of the current study was to examine the influences of leader self-efficacy and coaching career outcome expectancies on intentions for advancement in leadership careers of collegiate assistant coaches in the United States. We also investigated psychosocial antecedents of these factors and explored gender differences. Female and male collegiate assistant coaches (N = 674) participated in an online survey consisting of measurements of leadership career advancement intentions, leader self-efficacy, and coaching career outcome expectancies, and their putative antecedents (i.e., developmental challenges, head coach professional support, family-work conflicts, and perceived gender discrimination). Results showed that leader self-efficacy and coaching career outcome expectancies were related to coaches’ leadership career advancement intentions. Developmental challenges and head coach professional support were positively related to leader self-efficacy, while family-work conflicts and perceived gender discrimination were negatively related to coaching career outcome expectancies. Findings also suggested that female assistant coaches may have higher coaching career outcome expectancies, but lower intentions toward leadership career advancement, leader self-efficacy, and developmental challenges than male assistant coaches. The study findings suggest ways to advance junior coaches’ leadership careers.
Ca
2+
and mitochondrial ROS: Both hero and villain in membrane repair
Authors: Cooper Sandra T.
Published: September 2017

Ca
2+
and mitochondrial ROS orchestrate the survival or demise of cells with membrane injury (Horn
et al
., in 5 September 2017 issue).
Effective coverage of primary care services in eight high-mortality countries
Authors: Leslie Hannah H , Malata Address , Ndiaye Youssoupha , Kruk Margaret E
Published: September 2017

Introduction

Measurement of effective coverage (quality-corrected coverage) of essential health services is critical to monitoring progress towards the Sustainable Development Goal for health. We combine facility and household surveys from eight low-income and middle-income countries to examine effective coverage of maternal and child health services.

Methods

We developed indices of essential clinical actions for antenatal care, family planning and care for sick children from existing guidelines and used data from direct observations of clinical visits conducted in Haiti, Kenya, Malawi, Namibia, Rwanda, Senegal, Tanzania and Uganda between 2007 and 2015 to measure quality of care delivered. We calculated healthcare coverage for each service from nationally representative household surveys and combined quality with utilisation estimates at the subnational level to quantify effective coverage.

Results

Health facility and household surveys yielded over 40 000 direct clinical observations and over 100 000 individual reports of healthcare utilisation. Coverage varied between services, with much greater use of any antenatal care than family planning or sick-child care, as well as within countries. Quality of care was poor, with few regions demonstrating more than 60% average performance of basic clinical practices in any service. Effective coverage across all eight countries averaged 28% for antenatal care, 26% for family planning and 21% for sick-child care. Coverage and quality were not strongly correlated at the subnational level; effective coverage varied by as much as 20% between regions within a country.

Conclusion

Effective coverage of three primary care services for women and children in eight countries was substantially lower than crude service coverage due to major deficiencies in care quality. Better performing regions can serve as examples for improvement. Systematic increases in the quality of care delivered—not just utilisation gains—will be necessary to progress towards truly beneficial universal health coverage.
Guideline use behaviours and needs of primary care practitioners in China: a cross-sectional survey
Authors: Zeng Linan , Li Youping , Zhang Lingli , Liu Guanjian , Zhang Yang , Zhen Shangwei , Li Honghao , Song Xue , Duan Yanjun , Yu Jiajie , Wang Xiaodong
Published: September 2017

Objectives

Clinical guidelines have been recognised as an effective way to improve healthcare performance. However, little is known about the uptake and implementation of guidelines by general practitioners in China. The aim of this study was to investigate the guideline use behaviours and needs of practitioners in primary care settings in China.

Methods

We conducted a cross-sectional survey from December 2015 to May 2016 that included practitioners at 268 institutions in 15 provinces in China. Questionnaire development was informed by the execution of a literature review and consultation of experts. On-site surveys were implemented using a paper questionnaire to minimise missing responses. A multivariate logistic regression analysis was performed to identify factors associated with provider knowledge of and attitudes towards clinical guidelines.

Results

Of the respondents, 91.7% (1568/1708) were aware of clinical guidelines, but only 11.3% (177/1568) frequently used them. The main mechanism by which primary care practitioners accessed guidelines was public search engines (63.4%; 911/1438), and practitioners seldom reported using biomedical databases. The most frequently identified barriers to guideline use were lack of training (49.9%; 778/1560), lack of access (44.6%; 696/1560) and lack of awareness (38.0%; 592/1560). Less than one-quarter of respondents considered current guidelines ‘entirely appropriate’ for use in primary care (23.5%; 339/1442). Most participants (96.2%; 1509/1568) believed it was necessary to develop primary care guidelines. Provider attitudes towards current guidelines were associated with the location and level of the institution and professional title of the practitioner (p<0.05).

Conclusion

Our survey revealed poor knowledge and uptake of clinical guidelines in primary care, and we identified a gap between the needs of practitioners and availability of clinical guidelines for use in primary care in China. In addition, lacking access to and training in guidelines also prevented primary healthcare practitioners from using guidelines in daily practice.
Understanding symptom appraisal and help-seeking in people with symptoms suggestive of pancreatic cancer: a qualitative study
Authors: Mills Katie , Birt Linda , Emery Jon D , Hall Nicola , Banks Jonathan , Johnson Margaret , Lancaster John , Hamilton William , Rubin Greg P , Walter Fiona M
Published: September 2017

Objective

Pancreatic cancer has poor survival rates due to non-specific symptoms leading to later diagnosis. Understanding how patients interpret their symptoms could inform approaches to earlier diagnosis. This study sought to explore symptom appraisal and help-seeking among patients referred to secondary care for symptoms suggestive of pancreatic cancer.

Design

Qualitative analysis of semistructured in-depth interviews. Data were analysed iteratively and thematically, informed by the Model of Pathways to Treatment.

Participants and setting

Pancreatic cancer occurs rarely in younger adults, therefore patients aged ≥40 years were recruited from nine hospitals after being referred to hospital with symptoms suggestive of pancreatic cancer; all were participants in a cohort study. Interviews were conducted soon after referral, and where possible, before diagnosis.

Results

Twenty-six interviews were conducted (cancer n=13 (pancreas n=9, other intra-abdominal n=4), non-cancer conditions n=13; age range 48–84 years; 14 women). Time from first symptoms to first presentation to healthcare ranged from 1 day to 270 days, median 21 days. We identified three main themes. Initial symptom appraisal usually began with intermittent, non-specific symptoms such as tiredness or appetite changes, attributed to diet and lifestyle, existing gastrointestinal conditions or side effects of medication. Responses to initial symptom appraisal included changes in meal type or frequency, or self-medication. Symptom changes such as alterations in appetite and enjoyment of food or weight loss usually prompted further appraisal. Triggers to seek help included a change or worsening of symptoms, particularly pain, which was often a ‘tipping point’. Help-seeking was often encouraged by others. We found no differences in symptom appraisal and help-seeking between people diagnosed with cancer and those with other conditions.

Conclusions

Greater public and healthcare professional awareness of the combinations of subtle and intermittent symptoms, and their evolving nature, is needed to prompt timelier help-seeking and investigation among people with symptoms of pancreatic cancer.
Prevalence of stroke and associated risk factors: a population based cross sectional study from northeast China
Authors: Zhang Fu-Liang , Guo Zhen-Ni , Wu Yan-Hua , Liu Hao-Yuan , Luo Yun , Sun Ming-Shuo , Xing Ying-Qi , Yang Yi
Published: September 2017

Objectives

Epidemiological studies aimed at stroke and its risk factors can help identify persons at higher risk and therefore promote stroke prevention strategies. We aimed to explore the current prevalence of stroke and its associated risk factors in northeast China.

Design

Population based cross sectional study.

Setting

Data were collected using a structured precoded questionnaire designed by the Stroke Screening and Prevention Programme of the National Health and Family Planning Commission of China, between January and March 2016.

Participants

4100 permanent residents, aged 40 years or older, who had lived in Dehui City of Jilin Province for more than 6 months volunteered to participate in the survey, with a response rate of 92.2%. For the purpose of the present analysis, 48 subjects were excluded due to missing values, giving a total of 4052 people included in this analysis.

Main outcome measure

The questionnaire included demographic characteristics, stroke related behavioural factors, personal and family medical history of stroke, physical examination and laboratory testing.

Results

The overall prevalence of stroke in Jilin Province was 7.2% (95% CI 6.3% to 8.2%). Of all stroke cases, 91.7% (95% CI 87.4% to 94.6%) were ischaemic stroke and 8.3% (95% CI 5.4% to 12.6%) were haemorrhagic stroke. The prevalence rates of dyslipidaemia, smoking and hypertension were ranked as the top three cerebrovascular risk factors and were 62.1%, 61.8% and 57.3%, respectively. We found that hypertension, dyslipidaemia and lack of exercise were associated with ischaemic stroke. However, only hypertension (OR=4.064, 95% CI 1.358 to 12.160) was significantly associated with haemorrhagic stroke.

Conclusions

The prevalence of stroke, especially ischaemic stroke, and associated cerebrovascular risk factors among adults aged 40 years or older in northeast China were high. A higher regional prevalence of hypertension, dyslipidaemia and lack of exercise may be responsible.
Protocol for a qualitative study exploring perspectives on the INternational CLassification of Diseases (11th revision); Using lived experience to improve mental health Diagnosis in NHS England: INCLUDE study
Authors: Hackmann Corinna , Green Amanda , Notley Caitlin , Perkins Amorette , Reed Geoffrey M , Ridler Joseph , Wilson Jon , Shakespeare Tom
Published: September 2017

Introduction

Developed in dialogue with WHO, this research aims to incorporate lived experience and views in the refinement of the International Classification of Diseases Mental and Behavioural Disorders 11th Revision (ICD-11). The validity and clinical utility of psychiatric diagnostic systems has been questioned by both service users and clinicians, as not all aspects reflect their lived experience or are user friendly. This is critical as evidence suggests that diagnosis can impact service user experience, identity, service use and outcomes. Feedback and recommendations from service users and clinicians should help minimise the potential for unintended negative consequences and improve the accuracy, validity and clinical utility of the ICD-11.

Methods and analysis

The name INCLUDE reflects the value of expertise by experience as all aspects of the proposed study are co-produced. Feedback on the planned criteria for the ICD-11 will be sought through focus groups with service users and clinicians. The data from these groups will be coded and inductively analysed using a thematic analysis approach. Findings from this will be used to form the basis of co-produced recommendations for the ICD-11. Two service user focus groups will be conducted for each of these diagnoses: Personality Disorder, Bipolar I Disorder, Schizophrenia, Depressive Disorder and Generalised Anxiety Disorder. There will be four focus groups with clinicians (psychiatrists, general practitioners and clinical psychologists).

Ethics and dissemination

This study has received ethical approval from the Coventry and Warwickshire HRA Research Ethics Committee (16/WM/0479). The output for the project will be recommendations that reflect the views and experiences of experts by experience (service users and clinicians). The findings will be disseminated via conferences and peer-reviewed publications. As the ICD is an international tool, the aim is for the methodology to be internationally disseminated for replication by other groups.

Trial registration number

ClinicalTrials.gov:NCT03131505.
Open abdomen critical care management principles: resuscitation, fluid balance, nutrition, and ventilator management
Authors: Chabot Elizabeth , Nirula Ram
Published: September 2017

The term “open abdomen” refers to a surgically created defect in the abdominal wall that exposes abdominal viscera. Leaving an abdominal cavity temporarily open has been well described for several indications, including damage control surgery and abdominal compartment syndrome. Although beneficial in certain patients, the act of keeping an abdominal cavity open has physiologic repercussions that must be recognized and managed during postoperative care. This review article describes these issues and provides guidelines for the critical care physician managing a patient with an open abdomen.
Separate and combined effects of time of day and verbal instruction on knee extensor neuromuscular adjustments
Authors: Jaafar Hamdi , Lajili Hanene
Published: September 2017

We examined the effects of time of day and verbal instruction, separately and combined, on knee extensor neuromuscular adjustments, with special reference to rapid muscle force production capacity. Ten healthy male participants performed 4 experimental trials in counterbalanced order: morning “hard-and-fast” instruction, evening hard-and-fast instruction, morning “fast” instruction, and evening fast instruction. During each experimental trial, neuromuscular performance was assessed from the completion of 6 maximal isometric voluntary contractions (rest = 2 min) of the knee extensors with concomitant quadriceps surface electromyography recordings. For each contraction, we determined maximal voluntary force (Fmax), maximal rate of force development (RFDmax) and associated maximal electromechanical delay (EMDmax), and maximal rate of muscle activation (RMAmax). Globally, oral temperature (+2.2%), Fmax (+4.9%) and accompanying median frequency (+6.6%)/mean power frequency (+6.0%) as well as RFDmax (+13.5%) and RMAmax (+15.5%) were significantly higher in the evening than morning (p < 0.05). Conversely, evening in reference to morning values were lower for EMDmax (–4.3%, p < 0.05). Compared with a hard-and-fast instruction, RFDmax (+30.6%) and corresponding root mean square activity (+18.6%) were globally higher using a fast instruction (p < 0.05), irrespectively of the time of day. There was no significant interaction effect of time of day and verbal instruction on any parameter, except for EMDmax (p = 0.028). Despite diurnal variation in maximal or explosive force production of knee extensors and associated neuromuscular parameters, these adjustments occurred essentially independently of the verbal instruction provided.
Rescheduling to Minimize the Maximum Lateness Under the Sequence Disruptions of Original Jobs
Authors: Zhao Qiulan , Yuan Jinjiang
Published: September 2017

We introduce and study the rescheduling on a single machine to minimize the maximum lateness under the sequence disruptions of original jobs. In the problem, each original job [Formula: see text] has a constraint disruption on its sequence respect to an original optimal schedule [Formula: see text], i.e., [Formula: see text]. That is, if [Formula: see text] is the [Formula: see text]th job in [Formula: see text], then it is required that the position index [Formula: see text] of [Formula: see text] in a schedule for all jobs satisfies [Formula: see text]. By introducing the positive sequence disruption [Formula: see text] and the negative sequence disruption [Formula: see text], three problems are considered in this paper: problem (P1) is [Formula: see text], problem (P2) is [Formula: see text], and problem (P3) is [Formula: see text]. We show that the three problems are equivalent and can be solved in [Formula: see text] time. Then we study an extension of problem (P2): [Formula: see text]. We show that the extended problem can be solved in [Formula: see text] time.
Groups of prime generalized exponent
Authors: Abdollahi A. , Daoud B. , Farrokhi D. G. M. , Guerboussa Y.
Published: September 2017

A group [Formula: see text] satisfies a positive generalized identity of degree [Formula: see text] if there exist elements [Formula: see text] such that [Formula: see text] for all [Formula: see text]. The minimum degree of such an identity is called the generalized exponent of [Formula: see text]. Among other things, we prove that every finitely generated solvable group satisfying a positive generalized identity of prime degree is a finite [Formula: see text]-group. Consequently, we show that every finite group with a positive generalized identity of degree [Formula: see text] is a 5-group of exponent dividing 25.
STRUCTURAL PARAMETERS AND OPTOELECTRONIC PROPERTIES OF Mg-IV-V2 (IV=Si, Ge, Sn AND V=P, As) COMPOUNDS
Authors: IBRAHIM M. , ULLAH HAYAT , JAN SAEED ULLAH , ALI MANZAR , ASHIQ M. GULBAHAR
Published: September 2017

Semiconductors are the backbone of the optoelectronic industry. Direct band gap materials in the visible energy region are highly desirable for the efficient optoelectronic applications. In this work, we have probed the structural, electronic and optical properties of Mg-IV-V2 (IV[Formula: see text]Si, Ge, Sn and V[Formula: see text]P, As) compounds by FP-LAPW calculations, based on density functional theory. Their crystal structure is chalcopyrite with space group of I-42d. The lattice constants of MgSiP2, MgSiAs2 and MgGeAs2 are consistent with experimental results. These compounds show semiconductor behavior with direct band gap ranging from 1.3–2.15[Formula: see text]eV. Optical properties were also investigated. Optical properties include real and imaginary parts of dielectric constant, energy loss function, refraction and reflection. Direct band gap nature and good response in the visible region of these compounds predict their usefulness in optoelectronic devices.
A van der WAALS CORRECTED DFT STUDY OF CHEMICAL SENSING OF SULFUR DIOXIDE MOLECULE BY NITROGEN-DOPED Au DECORATED TiO2 NANOPARTICLES
Authors: ABBASI AMIRALI , SARDROODI JABER JAHANBIN
Published: September 2017

We have studied the adsorption of SO2 molecule on the pristine and nitrogen-doped Au decorated TiO2 nanoparticles using density functional theory (DFT) calculations, taking into attention van der Waals (vdW) interactions. Theoretically, it was found that SO2 molecule adsorbs on the Au decorated TiO2 in a bridge geometry. The adsorption of SO2 molecule on both the Au and TiO2 sides were considered. On the TiO2 side, the fivefold coordinated titanium sites were found to be the most stable binding sites, providing double contacting point between the nanoparticle and SO2. The results suggest that the adsorption of SO2 on the N-doped Au decorated TiO2 is more energetically favorable than the adsorption on the pristine one. Thus, nitrogen doping is dominant during the adsorption of SO2. The changes in the electronic structure of the system and the net charge transfer upon adsorption of SO2 molecule were studied in detail. Also, HOMO–LUMO isosurfaces of the adsorption systems were presented for discussion of results. By considering large overlaps in the projected density of states (PDOSs) of the interacting atoms, we found that the molecule is bound most strongly to the Au and fivefold coordinated titanium positions. The inclusion of vdW interactions is important for obtaining final equilibrium adsorption configurations of SO2 on Au decorated TiO2 nanoparticles. Our results thus suggest that N-doped Au decorated TiO2 would be an efficient sensor for SO2 gas detection in the environment.
Near-Optimal Regret Bounds for Thompson Sampling
Authors: Agrawal Shipra , Goyal Navin
Published: September 2017

Thompson Sampling (TS) is one of the oldest heuristics for multiarmed bandit problems. It is a randomized algorithm based on Bayesian ideas and has recently generated significant interest after several studies demonstrated that it has favorable empirical performance compared to the state-of-the-art methods. In this article, a novel and almost tight martingale-based regret analysis for Thompson Sampling is presented. Our technique simultaneously yields both problem-dependent and problem-independent bounds: (1) the first near-optimal problem-independent bound of
O
(√
NT
ln
T
) on the expected regret and (2) the optimal problem-dependent bound of (1 + ϵ)Σ
i
ln
T
/
d
(μ
i
,μ
1
) +
O
(
N
/ϵ
2
) on the expected regret (this bound was first proven by Kaufmann et al. (2012b)).

Our technique is conceptually simple and easily extends to distributions other than the Beta distribution used in the original TS algorithm. For the version of TS that uses Gaussian priors, we prove a problem-independent bound of
O
(√
NT
ln
N
) on the expected regret and show the optimality of this bound by providing a matching lower bound. This is the first lower bound on the performance of a natural version of Thompson Sampling that is away from the general lower bound of Ω (√
NT
) for the multiarmed bandit problem.
New Design of a Soft Robotics Wearable Elbow Exoskeleton Based on Shape Memory Alloy Wire Actuators
Authors: Copaci Dorin , Cano Enrique , Moreno Luis , Blanco Dolores
Published: September 2017

The elbow joint is a complex articulation composed of the humeroulnar and humeroradial joints (for flexion-extension movement) and the proximal radioulnar articulation (for pronation-supination movement). During the flexion-extension movement of the elbow joint, the rotation center changes and this articulation cannot be truly represented as a simple hinge joint. The main goal of this project is to design and assemble a medical rehabilitation exoskeleton for the elbow with one degree of freedom for flexion-extension, using the rotation center for proper patient elbow joint articulation. Compared with the current solutions, which align the exoskeleton axis with the elbow axis, this offers an ergonomic physical human-robot interface with a comfortable interaction. The exoskeleton is actuated with shape memory alloy wire-based actuators having minimum rigid parts, for guiding the actuators. Thanks to this unusual actuation system, the proposed exoskeleton is lightweight and has low noise in operation with a simple design 3D-printed structure. Using this exoskeleton, these advantages will improve the medical rehabilitation process of patients that suffered stroke and will influence how their lifestyle will change to recover from these diseases and improve their ability with activities of daily living, thanks to brain plasticity. The exoskeleton can also be used to evaluate the real status of a patient, with stroke and even spinal cord injury, thanks to an elbow movement analysis.
SUMO E3 Ligase PIASy Mediates High Glucose-Induced Activation of NF-κB Inflammatory Signaling in Rat Mesangial Cells
Authors: Huang Wei , Liang Yaling , Dong Jianhua , Zhou Luping , Gao Chenlin , Jiang Chunxia , Chen Meijuan , Long Yang , Xu Yong
Published: September 2017

Background. Sumoylation is extensively involved in the regulation of NF-κB signaling. PIASy, as a SUMO E3 ligase, has been proved to mediate sumoylation of IκB kinase γ (IKKγ) and contribute to the activation of NF-κB under genotoxic agent stimulation. However, the association of PIASy and NF-κB signaling in the pathogenesis of diabetic nephropathy (DN) has not been defined. Methods. Rat glomerular mesangial cells (GMCs) were stimulated by high glucose; siRNA was constructed to silence the expression of PIASy; the expression of PIASy, SUMO isoforms (SUMO1, SUMO2/3), and NF-κB signaling components was analyzed by Western blot; the interaction between IKKγ and SUMO proteins was detected by coimmunoprecipitation; and the release of inflammatory cytokines MCP-1 and IL-6 was assayed by ELISA. Results. High glucose significantly upregulated the expression of PIASy, SUMO1, and SUMO2/3 in a dose- and time-dependent manner (P<0.05), induced the phosphorylation and sumoylation of IKKγ (P<0.05), and then triggered NF-κB signaling whereas MCP-1 and IL-6 were released from GMCs (P<0.05). Moreover, these high glucose-induced effects were observably reversed by siRNA-mediated knockdown of PIASy (P<0.05). Conclusion. The SUMO E3 ligase PIASy mediates high glucose-induced activation of NF-κB inflammatory signaling, suggesting that PIASy may be a potential therapeutic target of DN.