bluuebunny/crossref_metadata_2025 huggingface dataset:
An Experimental and Analytical Study of Vortex-Flow Temperature Separation by Superposition of Spiral and Axial Flows: Part 1
Authors: Lay J. E.
Published: May 2019

This paper reports on an experimental and analytical study of compressible flow in a uniflow vortex tube. Part 1 deals with an experimental study, Part 2 with the analytical study. Its purpose is to provide a better understanding of the separation of a gas stream into regions of high and low stagnation temperatures, there being at present little agreement as to the theory of operation. The problem is first approached from the experimental standpoint. A large, multipurpose vortex tube is so designed and built that pressure, temperature, and velocity traverses can be taken at six different stations throughout the length of the tube. Pressure, temperature, and velocity traverses are taken by means of hypodermic probes. Velocities are checked by means of a miniature hot-wire anemometer. Data are taken for different runs of inlet pressures and plotted against radial distance. Flow visualization is obtained by means of liquid injection. The analytical study consists of using superposition for the solution of the flow equations. It begins with potential vortex flow in the plane. The solution of this flow is characterized by the existence of sonic or limit circles. Superposition of a sink flow to the vortex solution yields a spiral flow in the plane. The general solution in space is obtained by addition of a uniform axial velocity to the spiral flow. When viscosity effects are considered, the potential vortex changes into a forced vortex, and the solution becomes a superposition of a viscous compressible sink to a forced vortex. Performance or stagnation temperature separation is expressed as function of the ratio of vortex strength to sink strength.
Analytical Design of an Ackermann Steering Linkage
Authors: Wolfe W. A.
Published: May 2019

A method is outlined whereby the dimensions of an Ackermann steering linkage may be determined analytically. The theoretical relation between the angles of rotation of the front wheels of a vehicle is derived and it is shown how this relation may be approximated by a symmetrical four-bar linkage.

The method is briefly as follows:

The basic relation between the angles of the four-bar linkage is derived and the theoretically correct relation between the angles is used to express the four-bar linkage equation as a function of one variable. If this derived equation can be made equal to zero for a suitable range of wheel-turning angle by proper adjustment of the coefficients, then the magnitudes of the coefficients will determine the physical dimensions of the linkage.

A direction solution as indicated does not seem possible so an approximate solution is developed by expressing the derived equation as a power series and adjusting the coefficients of this series so that the sum of the lower order terms deviates the least from zero.
On the Necessity of Unsteady Flow in Fluid Machines
Authors: Dean Robert C.
Published: May 2019

It is shown that work can be done on, or by, a fluid in a frictionless flow process only if the flow is unsteady. The implications of this conclusion in the analysis of fluid machinery, and provisions which must be made in analysis to account for unsteady flow, are discussed.
Friction Factors for Turbulent Flow in Curved Pipes
Authors: Itō H.
Published: May 2019

The object of this paper is to furnish the engineer with reliable data on the friction factors to be used in computing the pressure losses for turbulent flow in smooth curved pipes. The empirical formulas proposed, backed by theoretical considerations, appear to define the influence of curvature upon the law of resistance with satisfactory accuracy.
Evaluation of Material Wear and Self-Welding in Sodium-Cooled Reactor Systems
Authors: Jerman R. B. , Williams R. C. , Leeser D. O.
Published: May 2019

Laboratory and prototype component tests were made to determine the degree of adhesion and self-welding of various bearing-couple materials in liquid sodium. A few tests were run in nitrogen and in argon. Temperatures were from 500 F to 1000 F and the static loads on the bearing surfaces were up to 10,000 psi. The harder materials showed better wear resistance generally than did the softer materials. However, each material has a service life depending upon the temperature, unit loads, nature of service, and environment.
Statistical Optimization of Regulators Employing a Binary Error Criterion
Authors: Milsum J. H.
Published: May 2019

The problem is considered of minimizing total costs of a regulator subject to both a steady reference input and a statistical load disturbance. A binary error criterion is used which directly relates the error magnitude to the economic penalty entailed by the error. In contrast it is not easy to relate the mean-square error to economic penalty. Experimental work shows that the amplitude probability density distributions in saturating loops are altered sufficiently from the Gaussian that the statistical linearization technique does not predict results with satisfactory accuracy in many cases of interest. The use of modified distributions alleviates this problem, but analog computer experiments provide the most satisfactory attack for complicated situations and are easily instrumented.
An Introduction to the Time-Modulated Acceleration Switching Electrohydraulic Servomechanism
Authors: Murtaugh Stephen A.
Published: May 2019

A discussion of a new concept in electrohydraulic control is presented in this paper. The usual hydraulic servomechanism design uses a d-c amplifier and a flow-control servo valve to obtain hydraulic flow proportional to the position or velocity error of the load. In the acceleration switching servo these components are replaced by an electronic multivibrator and an especially designed electrohydraulic-servo valve called an acceleration switching valve. System control is obtained through modulation of the multivibrator square-wave dwell time by which the driven-load acceleration is regulated. The servo valve behaves as a pure integrator throughout most of its operating frequency range. Use of this technique has resulted in increased reliability, excellent servo valve resolution, negligible center-shift due to temperature extremes, and near infinite pressure-gain characteristics.
Static and Dynamic Control Characteristics of Flapper-Nozzle Valves
Authors: Feng Tsun-Ying
Published: May 2019

A basic study was conducted on a flapper-nozzle hydraulic control valve to explore in detail its static and dynamic control characteristics. These static and dynamic control characteristics are presented and both the theoretical and experimental results compared. Correlation between the theoretical and experimental results were found to be quite good.
An Analysis of Axial Compressor Cascade Aerodynamics: Part I—Potential Flow Analysis With Complete Solutions for Symmetrically Cambered Airfoil Families
Authors: Mellor G. L.
Published: May 2019

A method is presented whereby complete potential flow solutions for any cascade geometry may be obtained with comparatively great rapidity on desk calculators. This solution is carried out for the case of symmetrically cambered airfoils such as the 65-series compressor and circular are airfoils and the results presented in a compact graphical form completely account for the potential flow effects of camber, profile, thickness, stagger, solidity, and angle of attack. Real fluid effects will be assessed and correlated in Part II using the present results as a supporting theory.
An Analysis of Axial Compressor Cascade Aerodynamics: Part II—Comparison of Potential Flow Results With Experimental Data
Authors: Mellor G. L.
Published: May 2019

The theoretical potential flow results of Part I are compared with the large number of NACA 65-series compressor blade data. It is found that a single empirical constant used to modify the theory permits reasonable predictions of turning or lift coefficient to be made for any cascade geometry in the unstalled regions of flow. Furthermore, it is demonstrated that the theory allows a considerable number of plus and minus stalling angle of attack data to be collapsed to a single empirical curve. Conversely such a curve, once established, allows stalling predictions to be made for any cascade geometry. One interesting point on this curve is the loading limit above which the cascade is always stalled.
Reversible Pump-Turbines for Sir Adam Beck-Niagara Pumping-Generating Station
Authors: Deriaz P. , Warnock J. G.
Published: May 2019

The paper describes the origin of the new machine and its application to the storage scheme at Sir Adam Beck-Niagara where it operates as a reversible pump-turbine. Description is given of its hydraulic characteristics and of some of the more important mechanical design features.
Application of Boundary-Layer Theory in Turbomachinery
Authors: Schlichting H.
Published: May 2019

Some of the results of a new approach to a theoretical and experimental study of flows through cascades.
Radial Equilibrium in Supersonic Compressors
Authors: Hammitt A. G. , Bogdonoff S. M.
Published: May 2019

The radial equilibrium of flow through nearly radial shock waves in supersonic compressors is considered. The most restricted useful cases for which equilibrium is possible are a normal shock in a rotor, an oblique shock in a stator, or a normal shock with variable total head in a stator. The equilibrium requirement restricts the range of solutions but many useful ones are still possible.
Résumé of the Supersonic-Compressor Research at NACA Lewis Laboratory
Authors: Wilcox Ward W. , Tysl Edward R. , Hartmann Melvin J.
Published: May 2019

Each phase of the supersonic-compressor program conducted at the NACA Lewis Laboratory is reviewed with a discussion of the objectives and results of the various experiments and associated analyses. Particular emphasis is placed on the state of development at the time the work was done, the advancement resulting due to this program, and the association of the several phases of the research program. The assembling of all the reference material of this program serves as a background for further work in the area of supersonic compressors or related fields. Included in this paper are a few comments on the results of the supersonic-compressor research program and a mention of possible future applications.
Structure and Deformation of Gradient Metal Foams Produced by Machining
Authors: Qiao Haipeng , Murthy Tejas G. , Saldana Christopher
Published: May 2019

The effects of surface structure on mechanical performance for open-cell aluminum foam specimens were investigated in the present study. A surface gradient for pore structure and diameter was introduced into open-cell aluminum foams by machining-based processing. The structure changes in the strut and pore network were evaluated by computed tomography characterization. The role of structure gradients in affecting mechanical performance was determined using digital volume correlation and in situ compression within the computed tomographic scanner. These preliminary results show that the strength of these materials may be enhanced through surface structural gradients.
Effect of Mg2Si Concentration on the Dry Sliding Wear Behavior of Al–Mg2Si Composite
Authors: Biswas Prosanta , Mondal Manas Kumar , Mandal Durbadal
Published: May 2019

The microstructural morphology and wear behavior of as-cast Al–X wt% Mg2Si (X = 0.0, 5.0, 10.0, 15.0, and 20.0) composites were investigated through optical microscopy (OM), energy dispersive X-ray (EDX) spectrometry, scanning electron microscopy (SEM), and field emission scanning electron microscopy (FESEM). The dry sliding wear behavior was studied against an EN 31 hardened steel disk at four different applied loads (19.6 N, 29.4 N, 39.2 N, and 49 N) with a sliding speed of 62.8 m/min for 1 h. The optical microscopy analysis exhibits that the primary Mg2Si particles average equivalent diameter and volume fraction are increased with an increase in Mg2Si (Mg and Si) concentration in the Al–Mg2Si composite. Therefore, the bulk hardness of the composites is increased, whereas the primary Mg2Si hardness decreased because the coarser primary Mg2Si particles have less compactness. The wear resistance of the commercially pure aluminum significantly improved due to Mg2Si reinforcement, and the wear resistance is increased with the increase in Mg2Si concentration up to 15.0 wt% and then decreased at 20.0 wt%. The tested composites worn surfaces and debris exhibit adhesion, delamination, microcutting-abrasion, abrasive- and oxidation-type wear mechanism.
Engineered Pressure Vessels for Marine Service Using ASME Section VIII, Division 2 and Division 3 Pressure Vessel Codes
Authors: Hayden Louis E. , Sims J. Robert
Published: May 2019

The need for more efficient and cost effective design of ship board equipment has never been greater. Pressure vessels on board ships can account for significant volume and weight and thus affect the overall performance of the vessel. Classically ship board pressure vessels have been designed to ASME Section VIII, Division 1. This code requires pressure vessels that are designed using a basic design by rule approach with a 3.5 to 1 design margin on specified minimum tensile strength. In recent years the ASME Standards Committee that is responsible for Section VIII has developed two design codes, Section VIII, Division 2 Alternative Rules for Construction of Pressure Vessels and Section VIII, Division 3 Alternative Rules for Construction of High Pressure Vessels. These pressure vessel design codes offer lower design margins, an improved design by rule approach for Division 2 and allow or require design by analysis based on the vessel operating conditions and environment such as cyclic service. Use of these codes can improve ship board vessel design by lowering the weight of vessels while providing a safe reliable pressure vessel.

Paper published with permission.
Regulatory Perspectives on ASME OM Code, Mandatory Appendix IV, Revision 0, “Inservice Testing of Air-Operated Valves in Light-Water Reactor Nuclear Power Plants”
Authors: Carneal Jason
Published: May 2019

The American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code) establishes the requirements for preservice and inservice testing and examination of certain components to assess their operational readiness in light-water reactor nuclear power plants. The Code of Federal Regulations (CFR) endorses and mandates the use of the ASME OM Code for testing air-operated valves in 10 CFR 50.55a(b)(3)(ii) and 10 CFR 50.55a(f)(4), respectively.

ASME has recently approved Mandatory Appendix IV, Revision 0. NRC currently anticipates that Mandatory Appendix IV will first appear in the 2014 Edition of the ASME OM Code. Publication of the 2014 Edition of the ASME OM Code begins the NRC rulemaking process to modify 10 CFR 50.55a to incorporate the 2014 Edition of the ASME OM Code by reference. NRC staff has actively participated in the development of Mandatory Appendix IV, Revision 0, through participation in the ASME OM Code Subgroup on Air-Operated Valves (SG-AOV). The purpose of this paper is to provide NRC staff perspectives on the contents and implementation of Mandatory Appendix IV, Revision 0. This paper specifically discusses Mandatory Appendix IV, Sections IV-3100, “Design Review,” IV-3300, “Preservice Test,” IV-3400, “Inservice Test,” IV-3600, “Grouping of AOVs for Inservice Diagnostic Testing,” and IV-3800, “Risk Informed AOV Inservice Testing.” These topics were selected based on input received during NRC staff participation in the SG-AOV and other industry meetings. The goal of this paper is to provide NRC staff perspectives on the topics of most interest to NRC staff and members of the SG-AOV.

Paper published with permission.
Overcoming Common Engineering-Program Problems With a Software Solution
Authors: Files Christina , Johnson Tim
Published: May 2019

The nuclear utility Inservice Testing (IST) Program Engineer is faced with a number of challenges on a daily basis. The burden of additional responsibility has been increasing dramatically in recent years because of personnel departure without staff replacement. This condition has increased the reliance on software to assist the program engineer in performing their assigned duties.

IST Program administration and implementation software can be the IST Program Engineer’s “best friend” when properly used. Newer Web-based software such as the Engineering Programs EP-Plus ENGAGE™ IST Software is designed to meet and exceed the requirements of ASME (formerly the American Society of Mechanical Engineers) Operations and Maintenance of Nuclear Power Plants (OM Code) and regulatory expectations while simultaneously improving the IST Program Engineer’s “quality of life.”

Web-based, fully supported, readily accessible IST software is one of the IST Program Engineer’s most important tools. The EP-Plus ENGAGE Software Suite is aligned with corporate strategies and objectives by using the latest technology to improve the way that engineering programs are managed. The standardized common platform can be cost-effectively expanded to include any engineering program at the unit, station, or fleet level.

The EP-Plus ENGAGE Suite covers the full range of engineering programs and provides the opportunity to realize benefits in an expedited manner while also allowing improvement in efficiency and cost reduction.

A series of figures and associated narrative text is used to provide the IST Program Engineer with information pertaining to the features and functionality of today’s IST software and associated engineering-program software solutions.

Paper published with permission.
New Reactors and New Engineering Programs for Motor-Operated Valves
Authors: Comstock Shawn , Gowin Mark
Published: May 2019

Several new reactors are currently under construction in the USA. Based on current construction schedules, Watts Bar 2 will be the first new reactor to go online for commercial generation since Watts Bar 1 was issued its operating license in 1996. New engineering programs will be going online with new reactors like Watts Bar 2. The startup of these new engineering programs is not without its own set of challenges. One of the programs has undergone a significant transformation since the last nuclear power plant started commercial operation in terms of industry implementation methods and regulatory requirements.

In 1996, the NRC issued Generic Letter 96-05 to communicate issues related to periodic verification (PV) of motor-operated valves (MOVs) and to request action by operating commercial power reactors to establish an MOV PV program. Subsequently, the regulations were revised to include a requirement to have an MOV PV program in Title 10, “Energy,” of the Code of Federal Regulations (10 CFR) 50.55a(b)(3)(ii). Generic Letters 89-10 (on MOV surveillance and testing) and 96-05 have been closed and today stand as historical references. Their provisions do not directly apply to new reactors, but there are many lessons available from MOV PV programs at operating sites in terms of safety, implementation, and cost.

There is only one consensus standard available to describe the requirements for an acceptable MOV PV program. This is contained in the ASME’s Operation and Maintenance of Nuclear Power Plants (OM Code) as Mandatory Appendix III. The U.S. Nuclear Regulatory Commission (NRC) previously endorsed this approach as a Code Case and is preparing a proposed change to 10 CFR 50.55a to incorporate by reference the ASME OM Code edition that includes Appendix III. This paper conveys the technical complexities and financial concerns faced by plant staff in making the right technical decisions for new program implementation at a new reactor in the USA.

Paper published with permission.
Regulatory Treatment of Nonsafety Systems in Passive Advanced Light-Water Reactors
Authors: Scarbrough Thomas
Published: May 2019

Some new nuclear power plants have advanced light-water reactor (ALWR) designs with passive safety systems that rely on natural forces, such as density differences, gravity, and stored energy, to supply safety-injection water and to provide reactor-core and containment cooling. Active systems in such passive ALWR designs are categorized as nonsafety systems with limited exceptions. Active systems in passive ALWR designs provide the first line of defense to reduce challenges to the passive systems in the event of a transient at the nuclear power plant. Active systems that provide a defense-in-depth function in passive ALWR designs need not meet all of the acceptance criteria for safety-related systems. However, there should be a high level of confidence that these active systems will be available and reliable when challenged. Multiple activities will provide confidence in the capability of these active systems to perform their defense-in-depth functions; these are collectively referred to as the Regulatory Treatment of Nonsafety Systems (RTNSS) program. The U.S. Nuclear Regulatory Commission (NRC) addresses policy and technical issues associated with RTNSS equipment in passive ALWRs in several documents. This paper discusses the NRC staff’s review of pumps, valves, and dynamic restraints within the scope of the RTNSS program in passive ALWRs.

Paper published with permission.
Vibration Qualification of Piping Systems
Authors: Olson David
Published: May 2019

A number of industry and U.S. Nuclear Regulatory Commission (NRC) requirements exist for the quantification and qualification of piping-system vibrations. An ASME Operating and Maintenance (OM) Standard was written to provide methods for obtaining piping vibration measurements and to define acceptance criteria for the evaluation and qualification of the vibrations. Described herein is an overview of this standard, ASME OM-3, “Vibration Testing of Piping Systems,” along with discussions of the acceptance criteria (Reference 1).

Paper published with permission.
Design and Test for a High-Temperature Molten Salt Pump
Authors: Li Zhong , Fu Yuan , Zhang Jianyu , Lin Liancheng , Huang Jianping , Mao Wenyu , Yang Dongsheng , Zhao Dandan , Wang Xiao
Published: May 2019

A high-temperature molten salt pump, described as mechanical, free-surface, centrifugal, vertical-shaft, sump type, working at 500°C [932°F] to 600°C [1112°F], has been developed for the Thorium-Based Molten Salt Reactor (TMSR). Flow passage components of the pump are made of Hastelloy C-276 to ensure sufficient strength and corrosion resistance at high temperature. Also, a heat shield plug with air-cooled channels was designed to separate the drive motor, seal elements, and bearings from intense radioactivity and to keep the temperature of the flange seal below 150°C [302°F] and the temperature of the bearing below 80°C [176°F]. A dry gas seal was used so that there is zero leakage. Furthermore, some analysis of hydraulics characteristics, temperature field, thermal stress, and strain was performed to research the pump’s performance, and then the temperature field and the hydraulics were measured to validate the analysis results. The results show that the hydraulics, thermal stress, and strain meet the design value very well. The pump has been successfully operated on a LiF-NaF-KF test loop for over 250 hr. at temperatures of 500°C [932°F] to 600°C [1112°F], speeds of 1050 to 1450rpm, and flows of 15 m3/h [66 gpm] to 25 m3/h [110 gpm].

Paper published with permission.
Addressing the Accuracy Concerns of Measuring MOV Stem Nut Wear From Diagnostic Testing
Authors: Reames Carter (Chuck)
Published: May 2019

Excessive stem nut thread wear represents a potential common-cause failure mode that could impact all rising-stem valves. The consequence of unexpected failure of stem nuts emphasizes the importance of improving condition monitoring and maintenance practice activities by identifying, quantifying and minimizing stem nut thread wear.

In the nuclear industry, motor-operated valve (MOV) diagnostics estimate stem nut thread wear on safety-related valves using the stem-to-stem nut transition time (zero plateau). But the stem-to-stem nut transition time could also be affected by other variables that would lead to an inaccurate calculation of wear. Using stem-to-stem nut transition time to estimate wear, coupled with generally erring on the conservative side, usually indicates wear that is more severe than actual. This method, combined with all of the unknown variables, results in nuclear plants using valuable outage resources and dose to pull good stem nuts unnecessarily. This white paper identifies some of the variables that can be mistakenly construed as wear and offers a method that more accurately and efficiently validates this wear.

Paper published with permission.
Qualification of Pumps and Valves for the Safety Injection Path of Nuclear Power Plants
Authors: Ganzmann Ingo , Schmidt Holger
Published: May 2019

The reliability of a nuclear power plant depends on the safe functioning of its components during its lifetime: from design through construction, operation and maintenance. This is valid for new build projects as well as for the current fleet. As plants undergo modifications for increased performance or extended lifetimes, component integrity becomes a critical factor in those efforts, particularly for safety-related plant functions. This paper focuses on the qualification of pumps and valves of the safety-injection path, considering new requirements. Going back to the Barsebäck event in the year 1992, it is known that insulation material may cause clogging. Consequently, the presence of debris material in the water may have an impact on the functioning of pumps and valves. For this purpose, AREVA has built new thermo-hydraulic test loops in its accredited test and inspection body (according to International Organization for Standardization (ISO) 17025 and 17020) to consider this effect as it relates to components qualification (Ref. 1). The main relevant aspects of these tests will be discussed together with corresponding thermal shock tests.

Paper published with permission.
Motivational Climate Profiles, Pubertal Status, and Well-Being Among Female Adolescent Aesthetic Sport Athletes
Authors: Kipp Lindsay E. , Bolter Nicole D. , Phillips Reichter Alison
Published: May 2019

Purpose: Girls participating in aesthetic sports may be at risk for disordered eating and low self-esteem. Informed by self-determination theory, the authors examined motivational climate profiles to understand how climate dimensions differentially relate to psychological needs satisfaction, self-esteem, and disordered eating. Methods: Female gymnasts, divers, and figure skaters (N = 183; mean age = 13.5) completed a survey to assess perceptions of the motivational climate, perceived sport competence, autonomy, relatedness, self-esteem, and dieting. Pubertal status was assessed to control for developmental differences. Results: Three profiles emerged: High Important Role/Low Performance, High Effort and Cooperation/High Rivalry, and Low Mastery/High Unequal Recognition and Punishment. A 3 × 2 multivariate analysis of variance revealed profile groups significantly differed on perceived autonomy, coach relatedness, and teammate relatedness. In addition, perceived competence, self-esteem, and dieting significantly differed by pubertal status. For autonomy, the High Important Role/Low Performance group reported the highest scores. For coach and teammate relatedness, the Low Mastery/High Unequal Recognition and Punishment group reported significantly lower scores than the other 2 groups. Postpubertal girls reported lower sport ability and self-esteem and greater dieting. Conclusion: Physical maturity and social context were important in explaining girls’ psychological needs satisfaction and well-being. Results add to the authors’ understanding of the complex nature and influence of the motivational climate.
Identification of variable lymphocyte receptors that can target therapeutics to pathologically exposed brain extracellular matrix
Authors: Umlauf Benjamin J. , Clark Paul A. , Lajoie Jason M. , Georgieva Julia V. , Bremner Samantha , Herrin Brantley R. , Kuo John S. , Shusta Eric V.
Published: May 2019

This study demonstrates targeting of blood-brain barrier disruption to deliver payloads at sites of neurological disease.
Speaker-independent auditory attention decoding without access to clean speech sources
Authors: Han Cong , O’Sullivan James , Luo Yi , Herrero Jose , Mehta Ashesh D. , Mesgarani Nima
Published: May 2019

Our system separates simultaneous voices and compares them with brain waves of a listener to amplify attended speech.
Layer-specific activation of sensory input and predictive feedback in the human primary somatosensory cortex
Authors: Yu Yinghua , Huber Laurentius , Yang Jiajia , Jangraw David C. , Handwerker Daniel A. , Molfese Peter J. , Chen Gang , Ejima Yoshimichi , Wu Jinglong , Bandettini Peter A.
Published: May 2019

Using laminar fMRI, we show that prediction and sensory inputs activate specific layers in human primary somatosensory cortex.
Emergence of exploratory look-around behaviors through active observation completion
Authors: Ramakrishnan Santhosh K. , Jayaraman Dinesh , Grauman Kristen
Published: May 2019

A robotic agent learns how to look around novel environments intelligently by directing the camera to best complete its observations.
Outcomes related to 10-min Apgar scores of zero in Japan
Authors: Shibasaki Jun , Mukai Takeo , Tsuda Kennosuke , Takeuchi Akihito , Ioroi Tomoaki , Sano Hiroyuki , Yutaka Nanae , Takahashi Akihito , Sobajima Hisanori , Tamura Masanori , Hosono Shigeharu , Nabetani Makoto , Iwata Osuke
Published: May 2019

Objective

Apgar scores of zero at 10 min strongly predict mortality and morbidity in infants. However, recent data reported improved outcomes among infants with Apgar scores of zero at 10 min. We aimed to review the mortality rate and neurodevelopmental outcomes of infants with Apgar scores of zero at 10 min in Japan.

Design

Observational study.

Patients

Twenty-eight of 768 infants registered in the Baby Cooling Registry of Japan between 2012 and 2016, at >34 weeks’ gestation, with Apgar scores of zero at 10 min who were treated with therapeutic hypothermia.

Interventions

We investigated the time of first heartbeat detection in infants with favourable outcomes and who had neurodevelopmental impairments or died.

Main outcome measures

Clinical characteristics, mortality rate and neurodevelopmental outcomes at 18–22 months of age were evaluated.

Results

Nine (32%) of the 28 infants died before 18 months of age; 16 (57%) survived, but with severe disabilities and 3 (11%) survived without moderate-to-severe disabilities. At 20 min after birth, 14 of 27 infants (52%) did not have a first heartbeat, 13 of them died or had severe disabilities and one infant, who had the first heartbeat at 20 min, survived without disability.

Conclusion

Our study adds to the recent evidence that neurodevelopmental outcomes among infants with Apgar scores of zero at 10 min may not be uniformly poor. However, in our study, all infants with their first heartbeat after 20 min of age died or had severe disabilities.
Gastric perforation through a hiatus hernia into the left lung in an 84-year-old woman
Authors: Fitzpatrick Daniel , Longondjo Mario
Published: May 2019

An 84-year-old woman presented to the emergency department with a sudden onset of chest pain, shortness of breath and vomiting. She had a medical history of hiatus hernia, gastro-oesophgeal reflux disease and asthma only, but had several recent courses of oral steroids to treat her asthma. Initially she was hypoxic, tachycardic and normotensive. ECG was normal, chest X-ray showed a hiatus hernia and right middle zone consolidation. Inflammatory markers were normal. CT angiogram was performed to exclude aortic pathology, for which it was negative. It did however show a large hiatus hernia which had perforated and was communicating with the left lung. The patient deteriorated clinically and became hypotensive and more hypoxic. She was transferred to the intensive care unit but died 36 hours later as she was too unwell to undergo any exploratory surgery.
Splenic infarction from vascular torsion in a child with normal splenic anatomy
Authors: Molina Adolfo L , Smola Cassi , Wu Chang L , Hofto Meghan E
Published: May 2019

This is a case of an 8-year-old, Caucasian boy with a complex prior medical history who presented with worsening, acute, left-sided abdominal pain and fever after empiric treatment for a urinary tract infection. Repeat urinalysis was negative for infection. A renal ultrasound assessing for occult perinephric abscess or nephronia revealed normal kidneys but found a tubular structure adjacent to the left kidney. A CT scan further revealed a splenic infarction secondary to torsion. He had a surgical evaluation but was treated empirically with piperacillin/tazobactam for 10 days due to concern for infectious complications following splenic infarction. He had complete resolution of his pain and symptoms. He received routine vaccines for asplenia prior to being discharged home without any further sequelae.
Primary progressive multiple sclerosis to be treated with ocrelizumab: a mistaken case of cobalamin deficiency
Authors: Feldman Sydney , Aljarallah Salman , Saidha Shiv
Published: May 2019

Cobalamin (vitamin B12) deficiency often manifests with neurologic symptoms and may rarely mimic multiple sclerosis (MS) among other neurological disorders. However, MRI changes associated with cobalamin deficiency are typically spinal predominant and distinct from MS-related changes. We report a case of a patient with cobalamin deficiency who was recommended by her primary neurologist to commence treatment with ocrelizumab, a potent anti-CD20 B-cell depleting monoclonal antibody, after being diagnosed with primary progressive MS. However, cervical spine MRI demonstrated changes classical of cobalamin deficiency including ‘inverted V sign’ signal hyperintensity and following parenteral cobalamin supplementation her neurological symptoms quickly and dramatically improved.
Financial incentives for physical activity in adults: systematic review and meta-analysis
Authors: Mitchell Marc S , Orstad Stephanie L , Biswas Aviroop , Oh Paul I , Jay Melanie , Pakosh Maureen T , Faulkner Guy
Published: May 2019

Objective

The use of financial incentives to promote physical activity (PA) has grown in popularity due in part to technological advances that make it easier to track and reward PA. The purpose of this study was to update the evidence on the effects of incentives on PA in adults.

Data sources

Medline, PubMed, Embase, PsychINFO, CCTR, CINAHL and COCH.

Eligibility criteria

Randomised controlled trials (RCT) published between 2012 and May 2018 examining the impact of incentives on PA.

Design

A simple count of studies with positive and null effects (‘vote counting’) was conducted. Random-effects meta-analyses were also undertaken for studies reporting steps per day for intervention and post-intervention periods.

Results

23 studies involving 6074 participants were included (64.42% female, mean age = 41.20 years). 20 out of 22 studies reported positive intervention effects and four out of 18 reported post-intervention (after incentives withdrawn) benefits. Among the 12 of 23 studies included in the meta-analysis, incentives were associated with increased mean daily step counts during the intervention period (pooled mean difference (MD), 607.1; 95% CI: 422.1 to 792.1). Among the nine of 12 studies with post-intervention daily step count data incentives were associated with increased mean daily step counts (pooled MD, 513.8; 95% CI:312.7 to 714.9).

Conclusion

Demonstrating rising interest in financial incentives, 23 RCTs were identified. Modest incentives ($1.40 US/day) increased PA for interventions of short and long durationsandafter incentives were removed, though post-intervention ‘vote counting’ and pooled results did not align. Nonetheless, and contrary to what has been previously reported, these findings suggest a short-term incentive ‘dose’ may promote sustained PA.
Life expectancy and disparities in survival among HIV-infected people receiving antiretroviral therapy: an observational cohort study in Kathmandu, Nepal
Authors: Bhatta Dharma N , Adhikari Ruchi , Karki Sushil , Koirala Arun K , Wasti Sharada P
Published: May 2019

Introduction

The advent of antiretroviral therapy (ART) has dramatically slowed down the progression of HIV. This study assesses the disparities in survival, life expectancy and determinants of survival among HIV-infected people receiving ART.

Methods

Using data from one of Nepal’s largest population-based retrospective cohort studies (in Kathmandu, Nepal), we followed a total of 3191 HIV-infected people aged 15 years and older who received ART over the period of 2004–2015. We created abridged life tables with age-specific survival rates and life expectancy, stratified by sex, ethnicity, CD4 cell counts and the WHO-classified clinical stage at initiation of ART.

Results

HIV-infected people who initiated ART with a CD4 cell count of >200 cells/cm3at 15 years had 27.4 (22.3 to 32.6) years of additional life. People at WHO-classified clinical stage I and 15 years of age who initiated ART had 23.1 (16.6 to 29.7) years of additional life. Life expectancy increased alongside the CD4 cell count and decreased as clinical stages progressed upward. The study cohort contributed 8484.8 person years, with an overall survival rate of 3.3 per 100 person years (95% CI 3.0 to 3.7).

Conclusions

There are disparities in survival among HIV-infected people in Nepal. The survival payback of ART is proven; however, late diagnosis or the health system as a whole will affect the control and treatment of the illness. This study offers evidence of the benefits of enrolling early in care in general and ART in particular.
Design and rationale of the MyHeartMate study: a randomised controlled trial of a game-based app to promote behaviour change in patients with cardiovascular disease
Authors: Gallagher Robyn , Chow Clara , Parker Helen , Neubeck Lis , Celermajer David , Redfern Julie , Tofler Geoffrey , Buckley Thomas , Schumacher Tracy , Ferry Cate , Whitley Alexandra , Chen Lily , Figtree Gemma
Published: May 2019

Introduction

Recurrence of cardiac events is common after a first event, leading to hospitalisations and increased health burden. Patients have difficulties achieving the lifestyle changes required for secondary prevention and access to secondary prevention programs is limited. This study aims to evaluate the impact of a game-based mobile app, MyHeartMate, which is designed to motivate engagement in secondary prevention behaviours for cardiovascular risk factors.

Methods and analysis

The MyHeartMate study is a randomised controlled trial with 6-month follow-up and blinded assessment of the primary outcome. Participants (n=394) with coronary heart disease will be recruited from hospitals in metropolitan Sydney and randomly allocated to standard care or the MyHeartMate app intervention. The intervention group will receive the app, which uses game techniques to promote engagement and lifestyle behaviour change for secondary prevention. The primary outcome is difference between the groups in physical activity (metabolic equivalent of task minutes/week) at 6 months. Secondary outcomes include change in low-density lipoprotein cholesterol, systolic blood pressure, medication adherence, body mass index, waist circumference, mood and dietary changes at 6 months. Data on app engagement, and patient perspectives of usability and acceptability, will also be analysed.

Ethics and dissemination

The study has received ethics approval from Northern Sydney Local Health District Human Research Ethics Committee. The study findings will be disseminated via peer-reviewed publications and presentation at international scientific meetings/conferences.

Trial registration number

ACTRN12617000869370; Pre-results.
A longitudinal observational study of back pain incidence, risk factors and occupational physical activity in Swedish marine trainees
Authors: Monnier Andreas , Larsson Helena , Nero Håkan , Djupsjöbacka Mats , Äng Björn O
Published: May 2019

Objectives

To evaluate the occurrence of low back pain (LBP) and LBP that limits work ability, to identify their potential early risks and to quantify occupational physical activity in Swedish Armed Forces (SwAF) marines during their basic 4 month marine training course.

Design

Prospective observational cohort study with weekly follow-ups.

Participants

Fifty-three SwAF marines entering the training course.

Outcomes

Incident of LBP and its related effect on work-ability and associated early risks. Occupational physical activity, as monitored using accelerometers and self-reports.

Results

During the training course, 68% of the marines experienced at least one episode of LBP. This yielded a LBP and LBP limiting work ability incidence rate of 13.5 (95% CI 10.4 to 17.8) and 6.3 (95% CI 4.2 to 10.0) episodes per 1000 person-days, respectively. Previous back pain and shorter body height (≤1.80 m) emerged as independent risks for LBP (HR 2.5, 95% CI 1.4 to 4.3; HR 2.0, 95% CI 1.2 to 3.3, respectively), as well as for LBP that limited work ability (HR 3.6, 95% CI 1.4 to 8.9; HR 4.5, 95% CI 2.0 to 10.0, respectively). Furthermore, managing fewer than four pull-ups emerged as a risk for LBP (HR 1.9, 95% CI 1.2 to 3.0), while physical training of fewer than three sessions per week emerged as a risk for LBP that limited work ability (HR 3.0, 95% CI 1.2 to 7.4). More than 80% of the work time measured was spent performing low levels of ambulation, however, combat equipment (≥17.5 kg) was carried for more than half of the work time.

Conclusions

Incidents of LBP are common in SwAF marines’ early careers. The link between LBP and previous pain as well as low levels of exercise highlights the need for preventive actions early on in a marine’s career. The role of body height on LBP needs further investigation, including its relationship with body-worn equipment, before it can effectively contribute to LBP prevention.
Factors associated with low birth weight in Afghanistan: a cross-sectional analysis of the demographic and health survey 2015
Authors: Das Gupta Rajat , Swasey Krystal , Burrowes Vanessa , Hashan Mohammad Rashidul , Al Kibria Gulam Muhammed
Published: May 2019

Objectives

This study aimed to investigate the factors associated with low birth weight (LBW) in Afghanistan.

Design

Cross-sectional study.

Setting

This study used data collected from the Afghanistan Demographic and Health Survey 2015.

Participants

Facility-based data from 2773 weighted live-born children enrolled by a two-stage sampling strategy were included in our analysis.

Primary and secondary outcome measures

The primary outcome was LBW, defined as birth weight <2.5kg.

Results

Out of 2773 newborns, 15.5% (n=431) had LBW. Most of these newborns were females (58.3%, n=251), had a mother with no formal schooling (70.5%, n=304), lived in urban areas (63.4%, n=274) or lived in the Central region of Afghanistan (59.7%, n=257). In multivariable analysis, residence in Central (adjusted OR (AOR): 3.4; 95% CI 1.7 to 6.7), Central Western (AOR: 3.0; 95% CI 1.5 to 5.8) and Southern Western (AOR: 4.0; 95% CI 1.7 to 9.1) regions had positive association with LBW. On the other hand, male children (AOR: 0.5; 95% CI 0.4 to 0.8), newborns with primary maternal education (AOR: 0.5; 95% CI 0.3 to 0.8), birth interval ≥48 months (AOR: 0.4; 95% CI 0.1 to 0.8), belonging to the richest wealth quintile (AOR: 0.2; 95% CI 0.1 to 0.6) and rural residence (AOR: 0.3; 95% CI 0.2 to 0.6) had decreased odds of LBW.

Conclusions

Multiple factors had association with LBW in Afghanistan. Maternal, Neonatal and Child Health programmes should focus on enhancing maternal education and promoting birth spacing to prevent LBW. To reduce the overall burden of LBW, women of the poorest wealth quintiles, and residents of Central, Central Western and South Western regions should also be prioritised. Further exploration is needed to understand why urban areas are associated with higher likelihood of LBW. In addition, research using nationally representative samples are required.
Informing the development of a standardised approach to measure antibiotic use in secondary care: a systematic review protocol
Authors: Patel Selina , Jhass Arnoupe , Hopkins Susan , Shallcross Laura
Published: May 2019

Introduction

Ecological and individual-level evidence indicates that there is an association between level of antibiotic exposure and the emergence and spread of antibiotic resistance. The Global Point Prevalence Survey in 2015 estimated that 34.4% of hospital inpatients globally received at least one antimicrobial. Antimicrobial stewardship to optimise antibiotic use in secondary care can reduce the high risk of patients acquiring and transmitting drug-resistant infections in this setting. However, differences in the availability of data on antibiotic use in this context make it difficult to develop a consensus of how to comparably monitor antibiotic prescribing patterns across secondary care. This review will aim to document and critically evaluate methods and measures to monitor antibiotic use in secondary care.

Methods and analysis

We will search Medline (Ovid), Embase (Ovid), Cumulative Index to Nursing and Allied Health Literature, Cochrane Central Register of Controlled Trials and websites of key organisations for published reports where an attempt to measure antibiotic usage among adult inpatients in high-income hospital settings has been made. Two independent reviewers will screen the studies for eligibility, extract data and assess the study quality using the Newcastle-Ottawa scale. A description of the methods and measures used in antibiotic consumption surveillance will be presented. An adaptation of the Affordability, Practicability, Effectiveness, Acceptability, Side-effects Equity framework will be used to consider the practicality of implementing different approaches to measuring antibiotic usage in secondary care settings. A descriptive comparison of definitions and estimates of (in)appropriate antibiotic usage will also be carried out.

Ethics and dissemination

Ethical approval is not required for this study as no primary data will be collected. The results will be published in relevant peer-reviewed journals and presented at relevant conferences or meetings where possible. This review will inform future approaches to scale up antibiotic consumption surveillance strategies to attempt to maximise impact through standardisation.

PROSPERO registration number

CRD42018103375