bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent Advancements in Machining With Abrasives
Authors: Guo Changsheng , Shi Zhongde , Mullany Brigid , Linke Barbara , Yamaguchi Hitomi , Chaudhari Rahul , Hucker Scott , Shih Albert
Published: May 2020

This paper presents the recent advancements and forthcoming challenges for abrasive machining with specific focus on the advancement of industrial applications. The most significant advancement of abrasive machining is in grinding applications of cubic boron nitride (CBN) abrasive. The advancement of CBN wheels, application of grinding models and simulation tools, development of high stiffness multi-axis grinding machines, and high-speed spindles have contributed to the growing industrial applications of grinding with plated and vitrified CBN wheels. Sustainability of abrasive machining also received more attention during the past two decades as global Fortune 500 corporations have included sustainability as a corporate goal. Abrasive machining will continue to be a critical process for manufacturing precision components in the decades to come. The advancement and adoption of additive manufacturing creates more unique challenges for abrasive machining of complex geometrical features which were impossible a few years ago. Furthermore, strategies for abrasive machining are needed to utilize the massive amount of process data available by connected factories. Therefore, it is expected that sustainability and data analytics for abrasive machining will become a more important focus for various manufacturers.
Uncertainty Quantification of Stochastic Impact Dynamic Oscillator Using a Proper Orthogonal Decomposition-Polynomial Chaos Expansion Technique
Authors: Bhattacharyya Biswarup , Jacquelin Eric , Brizard Denis
Published: May 2020

A proper orthogonal decomposition (POD)-based polynomial chaos expansion (PCE) is utilized in this article for the uncertainty quantification (UQ) of an impact dynamic oscillator. The time-dependent nonsmooth behavior and the uncertainties are decoupled using the POD approach. The uncertain response domain is reduced using the POD approach, and the dominant POD modes are utilized for the UQ of the response quantity. Furthermore, the PCE model is utilized for the propagation of the input uncertainties. Two different cases of impact oscillator are considered, namely, single impact and multiple impact. The contact between two bodies is modeled by Hertz’s law. For both the cases, UQ is performed on the projectile displacement, projectile velocity, and contact force. A highly nonsmooth behavior is noticed for the contact force. For that reason, most number of POD modes are required to assess the UQ of contact force. All the results are compared with the Monte Carlo simulation (MCS) and time domain PCE results. Very good accuracies are observed for the PCE and the POD-PCE predicted results using much less number of model evaluations compared to MCS. As the PCE coefficients are dependent on time, the PCE model is computed at each time step. On the contrary, for the POD-PCE model, the PCE coefficients are computed for the number of POD modes only: it is much less than the PCE model.
A Surface Energy Density-Based Theory of Nanoelastic Dynamics and Its Application in the Scattering of P-Wave by a Cylindrical Nanocavity
Authors: Jia Ning , Peng Zhilong , Yao Yin , Chen Shaohua
Published: May 2020

The scattering of elastic waves in nanoporous materials is inevitably influenced by the surface effect of nanopores. In order to investigate such a dynamic problem with surface effect of nanomaterials, a new theory of nanoelastic dynamics is proposed, in which both the effect of surface free energy and the effect of surface inertia force are included. With the new theory, a scattering of plane compressional waves (P-wave) by a cylindrical nanocavity is analyzed, and the corresponding dynamic stress concentration factor (DSCF) around the nanocavity is analytically solved. It is found that, when the size of cavity is at a nanoscale, the surface energy effect leads to a reduction of the maximum DSCF comparing with the classical counterpart without surface effect, while the surface inertial effect enlarges the maximum DSCF. The surface inertial effect gradually becomes dominant over the surface energy effect with an increasing incident wave frequency. Although both kinds of surface effects tend to vanish with an increasing cavity radius, the surface inertial effect can exist in a submicron-sized cavity if the wave frequency is sufficiently high. All these results should be of guiding value not only for an optimal design of porous structure possessing a better dynamic load bearing capacity but also for the non-destructive detection of nano-defects.
Thermal Performance Analysis and Heat Transfer Enhancement Study in an Antminer Mining Machine
Authors: Chu Wen-Xiao , Chang Yao-Wen , Hu Yi-Yu , Wang Chi-Chuan
Published: May 2020

In this paper, the thermal performance of an AntMiner mining machine containing 189 chips on three printed circuit board (PCBs) is experimentally studied. The numerical method is applied to analyze the local airflow and thermal distribution alongside the flow direction and shows a good agreement with the experimental results. Some hot-spot regions are identified where chips might suffer under high-temperature operating condition. Meanwhile, the highly compact arrangement may result in pronounced bypass and jeopardize the thermal performance of the mining machine rapidly; thereby, the airflow management strategy for such confined compartment is implemented. The result shows that the flowrate distribution can be notably improved. Although the total flowrate is slightly reduced by 4.4%, the maximum chip temperature on three PCBs can be reduced by 3.2 °C, 3.5 °C, and 3.0 °C, and the corresponding improvement on thermal performance reaches 13.3%, 15.6%, and 13.0%, respectively. Furthermore, the maximum temperature of the downstream chips will be reduced by 2.5 °C when incorporating the “partial bypass” design by the removal of 12 backside heat sinks. The corresponding heat transfer performance is improved by 8.9–13.9%.
Experimental and Computational Methods for the Evaluation of Double-Wall, Effusion Cooling Systems
Authors: Murray Alexander V. , Ireland Peter T. , Romero Eduardo
Published: May 2020

Further improvements in gas turbine efficiency can be sought through more advanced cooling systems—such as the double-wall, effusion system—which provide high cooling effectiveness with low coolant utilization. The double-wall system, as described here, comprises two walls: one with a regular array of impingement holes and the other with a closely packed, regular array of film holes (characteristic of effusion systems). These walls are mechanically and thermally connected via a bank of pedestals which increase coolant wetted area and turbulent flow features. However, a lack of data exists in the open literature on these systems. This study presents a novel experimental heat transfer facility designed with the intent of investigating flat plate versions of such double-wall geometries. Key features of the facility are presented including the use of recirculation to increase the mainstream-to-coolant temperature ratio and the use of infrared thermography to obtain thermal measurements. Some rig commissioning characteristics are also provided which demonstrate well-conditioned, uniform flow. Both coolant and mainstream Reynolds numbers are matched to engine conditions, with the Biot number within around 15% of engine conditions. The facility is used to assess the cooling performance of four double-wall effusion geometries which incorporate various geometrical features. Both overall effectiveness and film effectiveness measurements are presented at a range of coolant mass flows with conclusions drawn as to preferable features from a cooling perspective. The results from a fully conjugate computational fluid dynamics (CFD) model of the facility are presented which utilized boundary conditions obtained during experimental runs. Additionally, a computationally efficient decoupled conjugate method developed previously by the authors was adapted to assess the experimental geometries with the results comparing favorably.
Forced Convection Computational Fluid Dynamics Analysis of Architected and Three-Dimensional Printable Heat Sinks Based on Triply Periodic Minimal Surfaces
Authors: Al-Ketan Oraib , Ali Mohamed , Khalil Mohamad , Rowshan Reza , Khan Kamran A. , Abu Al-Rub Rashid K.
Published: May 2020

The drive for small and compact electronic components with higher processing capabilities is limited by their ability to dissipate the associated heat generated during operations, and hence, more advanced heat sink designs are required. Recently, the emergence of additive manufacturing techniques facilitated the fabrication of complex structures and overcame the limitation of traditional techniques such as milling, drilling, and casting. Therefore, complex heat sink designs are now easily realizable. In this study, we propose a design procedure for mathematically realizable architected heat sinks and investigate their performance using the computational fluid dynamics (CFD) approach. The proposed heat sinks are mathematically designed with topologies based on triply periodic minimal surfaces (TPMSs). Three-dimensional CFD models are developed using the starccm+ platform for uniform heat sinks and topologically graded heat sinks to study the heat transfer performance in forced convection domains. The overall heat transfer coefficient, surface temperature, and pressure drop versus the input heat sources as well as the Reynolds number are used to evaluate the heat sink performance. Moreover, temperature contours and velocity streamlines were examined to analyze the fluid flow behavior within the heat sinks. Results showed that the tortuosity and channel complexity of the Diamond solid-networks heat sink result in a 32% increase in convective heat transfer coefficient compared with the Gyroid solid-network heat sink which has the comparable surface area under the examined flow conditions. This increase is at the expense of increased pressure drops which increases by the same percentage. In addition, it was found that expanding channel size along flow direction using the porosity grading approach results in significant pressure drop (27.6%), while the corresponding drop in convective heat transfer is less significant (15.7%). These results show the importance of employing functional grading in the design of heat sinks. Also, the manufacturability of the proposed designs was assessed using computerized tomography (CT) scan and scanning electron microscopy (SEM) imaging performed on metallic samples fabricated using powder bed fusion techniques. A visible number of internal manufacturing defects can affect the performance of the proposed heat sinks.
Challenges Associated With Replicating Rotor Blade Deposition in a Non-Rotating Annular Cascade
Authors: Bowen Christopher P. , Ameri Ali , Bons Jeffrey P.
Published: May 2020

A computational analysis is performed to determine if particulate impact events on the external surfaces of gas turbine engine rotor blades can be faithfully replicated in an experimental rotor cascade. The general electric (GE) energy efficient engine (E3) first-stage turbine flow-field at cruise conditions is first solved using a steady-state explicit mixing plane (MP) approach. To model flow in the cascade, a single E3 rotor periodic domain is then constructed with an inlet section matching the relative flow incidence angle from the mixing plane calculation. The mass-averaged relative flow conditions at the inlet and outlet of the mixing plane rotor section are imposed on the cascade boundaries and a steady solution is found. Particles with diameters ranging from 1 to 25 µm are tracked through each domain and the OSU deposition model is implemented to dictate the sticking and rebounding action of particles impacting solid surfaces. It is discovered that both the locations and parameters of the impacts in the cascade vary significantly from the engine environment. For smaller particles, this is credited to a stronger upstream influence of the blade on the cascade flow-field. As size increases, differences in deposition are instead driven by the interaction of the full-stage vane with the particles. The lack of a vane in the cascade causes drastically different particle inlet vectors over the rotor than are seen in the engine setting. The radial differences of particle impact locations are explored, and the role that pressure plays is considered.
Corner Stall Prediction in a Compressor Linear Cascade Using Very Large Eddy Simulation Lattice-Boltzmann Method
Authors: Maros Antoine , Bonnal Benoît , Gonzalez-Martino Ignacio , Kopriva James , Polidoro Francesco
Published: May 2020

Compressor corner stall is a phenomenon difficult to predict with numerical tools but essential to the design of axial compressors. Predictive methods are beneficial early in the design process to understand design and off-design limitations. Prior numerical work using Navier–Stokes computational methods has assessed the prediction capability for corner stall. Reynolds-averaged Navier–Stokes (RANS) simulations using several turbulence models have shown to over-predict the region of corner hub stall where large eddy simulations (LES) and detached eddy simulations (DES) approaches improved the airfoil surface and wake pressure loss prediction. A linear compressor cascade designed and tested at Ecole Centrale de Lyon provides a good benchmark for the evaluation of the accuracy of numerical methods for corner stall. This paper presents results obtained with Lattice-Boltzmann method (LBM) coupled with very large-eddy simulations (VLES) approach of PowerFLOW and compares them with the experimental and numerical work from Ecole Centrale de Lyon. The ability to achieve equivalent accuracy at a lower computational cost compared to LES scale resolving methods can enable multi-stage design and off-design compressor predictions. A methodical approach is taken by first accurately simulating the upstream flow conditions. Geometric trips are modeled upstream on the endwalls to match both the mean and fluctuating inflow boundary layer conditions. These conditions were then applied to the simulation of the linear compressor cascade. The benchline experimental study includes trips on both the pressure and suction of the airfoil. These trips are also included for the current simulation. The significance of capturing both inflow conditions and including trips on the airfoil is assessed. Detailed comparisons are then made to airfoil loading and downstream losses between experiment and previous RANS and LES simulations. LBM-VLES corner stall results of pitchwise averaged total pressure match LES agreement relative to experimental data at 50 times lower computational cost.
Objectively Measured Physical Activity and Polypharmacy Among Brazilian Community-Dwelling Older Adults
Authors: Bielemann Renata M. , Silveira Marysabel P.T. , Lutz Bárbara H. , Miranda Vanessa I.A. , Gonzalez Maria Cristina , Brage Soren , Ekelund Ulf , Bertoldi Andréa Dâmaso
Published: May 2020

Background: Previous observations regarding association between physical activity (PA) and use of medicines among older adults are derived from self-reported PA. This study aimed to evaluate the association between objectively measured PA and polypharmacy among older adults with multimorbidity in Southern Brazil.Methods: This study included 875 noninstitutionalized older people, aged ≥60 years. Prescribed medicines used in the 15 days prior to the interview, socioeconomic data, and the presence of comorbidities were self-reported. Accelerometers were used to evaluate PA following the interview.Results: Prevalence of polypharmacy (≥5 medicines) was 38.3% (95% confidence interval, 35.0–41.5); those belonging to the lowest tertile of PA used more medicines. The authors observed a significant inverse association for polypharmacy between men belonging to the second and third tertiles of PA for objectively measured overall PA and light PA compared with the most inactive tertile. For women, the association between PA and polypharmacy was significant for overall, light, and moderate to vigorous PA only in the third tertile.Conclusions: Overall, light and moderate to vigorous PA were inversely associated to polypharmacy and differed by gender. Promotion of PA in older adults may be an effective intervention to reduce the number of medicines used independent of the number of comorbidities.
We Are the Champions, But How Do We Respond? Savoring and Dampening in Response to Championship Victories Among Passionate Sports Fans
Authors: Schellenberg Benjamin J.I. , Verner-Filion Jérémie , Gaudreau Patrick
Published: May 2020

The aim of this research was to test if the ways passionate sport fans respond immediately after an important team victory depend on the extent to which passion is harmonious or obsessive. Fans of Liverpool F.C. (n = 299) and the Winnipeg Blue Bombers (n = 334) completed online surveys shortly after their teams had won an important championship game. Fans answered questions assessing passion and the extent to which they engaged in savoring (i.e., attempting to maintain, augment, or prolong positive emotions) and dampening (i.e., attempting to stifle positive emotions) after the victory. In both samples, the authors found that both harmonious and obsessive passion predicted greater savoring, but only obsessive passion predicted greater dampening. These findings build on previous research and suggest an additional reason for which harmonious and obsessive passion among sport fans tend to predict more and less adaptive outcomes, respectively.
Stroboscopic Vision as a Dynamic Sensory Reweighting Alternative to the Sensory Organization Test
Authors: Kim Kyung-Min , Kim Joo-Sung , Oh Jeonghoon , Grooms Dustin R.
Published: May 2020

Context: The sensory organization test (SOT) is a standard for quantifying sensory dependence via sway-referenced conditions (sway-referenced support and sway-referenced vision [SRV]). However, the SOT is limited to expensive equipment. Thus, a practical version of the SOT is more commonly employed—the clinical test for sensory integration in balance; however, it fails to induce postural instability to the level of SRV. Objective: Determine if Stroboscopic vision (SV), characterized by intermittent visual blocking, may provide an alternative to the SRV for assessing postural stability. Design: Descriptive laboratory study. Setting: Research laboratory. Participants: Eighteen participants (9 males, 9 females; age = 22.1 [2.1] y, height = 169.8 [8.5] cm, weight = 66.5 [10.6] kg). Intervention: Participants completed the SOT conditions, and then repeated SOT conditions 2 and 5 with SV created by specialized eyewear. Main Outcome Measures: A repeated-measures analysis of variance was completed on the time-to-boundary metrics of center-of-pressure excursion in the anteroposterior and mediolateral directions in order to determine the difference between the full-vision, SV, and SRV conditions. Results: Postural stability with either SRV or SV was significantly worse than with full vision (P < .05), with no significant difference between SV and SRV (P > .05). Limits of agreement analysis revealed similar effects of SV and SRV except for unstable surface mediolateral time-to-boundary. Conclusions: In general, SV was found to induce a degree of postural instability similar to that induced by SRV, indicating that SV could be a portable and relatively inexpensive alternative for the assessment of sensory dependence and reweighting.
Injuries in Collegiate Ladies Gaelic Footballers: A 2-Season Prospective Cohort Study
Authors: O’Connor Siobhán , Bruce Conor , Teahan Calvin , McDermott Elaine , Whyte Enda
Published: May 2020

Context: Although Ladies Gaelic football is one of the most popular female sports in Ireland, just 2 previous injury surveillance studies have been completed, and both were retrospective in nature. Objective: To prospectively examine the injury incidence and injury profile in collegiate Ladies Gaelic football over 2 seasons. Design: Prospective cohort study. Setting: College. Patients (or Other Participants): Adult Ladies Gaelic footballers from one collegiate institution (season 1: n = 50, season 2: n = 82). Intervention(s): All time-loss injuries that occurred were recorded by certified athletic therapists and student-athletic therapists and trainers over 2 seasons. Main Outcome Measures: A standardized injury report form was used to record the injury onset, mechanism, location, nature, and outcome. Injury incidence proportion, repeat incidence proportion and total, match and training injury rates, and their 95% confidence intervals were calculated. The frequencies and proportions were also calculated. Results: The match and training injury rates were 42.48 and 7.93 injuries per 1000 hours, respectively. A low repeat incidence proportion per season was noted (11.7% and 0.0%). The injuries were predominantly acute (74.68%) and noncontact (66.25%), with hamstring injuries (21.52%) and strains (36.71%) the most frequent location and nature of injuries noted. Strains (104.92 d absent per 1000 h) and knee injuries (106.46 d absent per 1000 h) led to the greatest injury burden. Further investigations were not frequently required, with an X-ray and magnetic resonance imaging ordered in 8.00% and 6.67% of the cases, respectively. Surgery was completed following one injury. Conclusions: This is the first study to provide prospective injury data on Ladies Gaelic football. Priority needs to be given to preventing hamstring and knee injuries due to their occurrence and negative impact on player availability to play. Collegiate Ladies Gaelic football teams should be encouraged to implement an injury-prevention warm-up, such as the GAA15+, at training and matches.
Reliability of a Novel Semiautomated Ultrasound Segmentation Technique for Assessing Average Regional Femoral Articular Cartilage Thickness
Authors: Lisee Caroline , McGrath Melanie L. , Kuenze Christopher , Zhang Ming , Salzler Matt , Driban Jeffrey B. , Harkey Matthew S.
Published: May 2020

Context: Ultrasound imaging is a clinically feasible tool to assess femoral articular cartilage and may have utility in tracking early knee osteoarthritis development. Traditional assessment techniques focus on measurements at a single location, which can be challenging to adopt for novice raters. Objective: To introduce a novel semiautomated ultrasound segmentation technique and determine the intrarater and interrater reliability of average regional femoral articular cartilage thickness and echo intensity of a novice and expert rater. Design: Descriptive observational study. Setting: Orthopedic clinic. Patients or Other Participants: Fifteen participants (mean [SD]; age 23.5 [4.6] y, height = 172.6 [9.3] cm, mass = 79.8 [15.7] kg) with a unilateral history of anterior cruciate ligament reconstruction participated. Intervention: None. Main Outcome Measures: One rater captured anterior femoral cartilage images of the participants’ contralateral knees using a transverse suprapatellar ultrasound assessment. The total femoral cartilage cross-sectional area of each image was segmented by a novice and expert rater. A novel custom program automatically separated the cartilage segmentations into medial, lateral, and intercondylar regions to determine the cross-sectional area and cartilage length. The average cartilage thickness in each region was calculated by dividing the cross-sectional area by the cartilage length. Echo intensity was calculated as the average gray-scale pixel value of each region. Two-way random effect intraclass correlations coefficient (ICC) for absolute agreement were used to determine the interrater reliability between a novice and expert rater, as well as the intrarater reliability of the novice rater. Results: The novice rater demonstrated excellent intrarater (ICC [2,k] range = .993–.997) and interrater (ICC [2,k] range = .944–.991) reliability with the expert rater of all femoral articular cartilage average thickness and echo intensity regions. Conclusions: The novel semiautomated average cartilage thickness and echo-intensity assessment is efficient, systematic, and reliable between an expert and novice rater with minimal training.
Probing the hydrothermal system of the Chicxulub impact crater
Authors: Kring David A. , Tikoo Sonia M. , Schmieder Martin , Riller Ulrich , Rebolledo-Vieyra Mario , Simpson Sarah L. , Osinski Gordon R. , Gattacceca Jérôme , Wittmann Axel , Verhagen Christina M. , Cockell Charles S. , Coolen Marco J. L. , Longstaffe Fred J. , Gulick Sean P. S. , Morgan Joanna V. , Bralower Timothy J. , Chenot Elise , Christeson Gail L. , Claeys Philippe , Ferrière Ludovic , Gebhardt Catalina , Goto Kazuhisa , Green Sophie L. , Jones Heather , Lofi Johanna , Lowery Christopher M. , Ocampo-Torres Rubén , Perez-Cruz Ligia , Pickersgill Annemarie E. , Poelchau Michael H. , Rae Auriol S. P. , Rasmussen Cornelia , Sato Honami , Smit Jan , Tomioka Naotaka , Urrutia-Fucugauchi Jaime , Whalen Michael T. , Xiao Long , Yamaguchi Kosei E.
Published: May 2020

The Chicxulub impact event generated a long-duration hydrothermal system suitable for microbial life.
Discovery of direct-acting antiviral agents with a graphene-based fluorescent nanosensor
Authors: Park Se-Jin , Kim Jungho , Kang Seounghun , Cha Hyung Jin , Shin Hojeong , Park Jisang , Jang Yong-Suk , Woo Jae-Sung , Won Cheolhee , Min Dal-Hee
Published: May 2020

We report a novel high-throughput screening tool for drug discovery of direct-acting antiviral agents against RNA viruses.
Understanding efficiency and the effect of pay-for-performance across health facilities in Tanzania
Authors: Binyaruka Peter , Anselmi Laura
Published: May 2020

Background

Ensuring efficient use and allocation of limited resources is crucial to achieving the UHC goal. Performance-based financing that provides financial incentives for health providers reaching predefined targets would be expected to enhance technical efficiency across facilities by promoting an output-oriented payment system. However, there is no study which has systematically assessed efficiency scores across facilities before and after the introduction of pay-for-performance (P4P). This paper seeks to fill this knowledge gap.

Methods

We used data of P4P evaluation related to healthcare inputs (staff, equipment, medicines) and outputs (outpatient consultations and institutional deliveries) from 75 health facilities implementing P4P in Pwani region, and 75 from comparison districts in Tanzania. We measured technical efficiency using Data Envelopment Analysis and obtained efficiency scores across facilities before and after P4P scheme. We analysed which factors influence technical efficiency by regressing the efficiency scores over a number of contextual factors. We also tested the impact of P4P on efficiency through a difference-in-differences regression analysis.

Results

The overall technical efficiency scores ranged between 0.40 and 0.65 for hospitals and health centres, and around 0.20 for dispensaries. Only 21% of hospitals and health centres were efficient when outpatient consultations and deliveries were considered as output, and <3% out of all facilities were efficient when outpatient consultations only were considered as outputs. Higher efficiency scores were significantly associated with the level of care (hospital and health centre) and wealthier catchment populations. Despite no evidence of P4P effect on efficiency on average, P4P might have improved efficiency marginally among public facilities.

Conclusion

Most facilities were not operating at their full capacity indicating potential for improving resource usage. A better understanding of the production process at the facility level and of how different healthcare financing reforms affects efficiency is needed. Effective reforms should improve inputs, outputs but also efficiency.
Managing mental health on a prolonged deployment: UK military exercise SAIF SAREEA 3
Authors: Sawford H J , Smith M B
Published: May 2020

Introduction

This paper presents the burden of mental health cases throughout UK military exercise SAIF SAREEA 3 (SS3), a low-tempo armoured brigade exercise in Oman from June to November 2018, and aims to discuss ways that mental health may be better managed on future large exercises.

Methods

A retrospective review of all attendances at army medical facilities and relevant computerised medical records was undertaken.

Results

14 mental health cases were identified, which required 51 follow-up presentations throughout the duration of SS3. This represented 1.2% of all first patient presentations, and 6.3% of all follow-up work. 64% had diagnoses which predated deployment and could all be classified within 10th revision of International Statistical Classification of Diseases and Related Health Problems as either F30–F39 mood (affective) disorders, or F40–F48 neurotic, stress-related and somatoform disorders; all new diagnoses made while deployed were adjustment disorders. The medical officer spent an average of 147 min total clinical care time per patient. Six patients were aeromedically evacuated (AE), which represented 26% of all AE cases from SS3.

Conclusions

Presentations were low, but time consuming and with poor disposal outcomes. Most conditions predated the exercise, and could have been predicted to worsen through the deployment. Given the disproportionate burden that mental health cases afforded during SS3, future brigade-sized deployments should include deployed mental health professionals in order to offer evidence-based therapy which should lead to improved disposal outcomes and a reduced AE burden.
Microscopic and macroscopic comparisons of 0.223 soft point and full metal jacket ammunition with bos taurus scapulae as a proxy to human flat bones
Authors: Taylor Seth C , Kieser D C , Hammer N , Pullen A , Hooper G
Published: May 2020

Background

The prevalence of civilian 0.223 ammunition is widespread. Due to low costs and the same dimensions as a 5.56×45 mm North Atlantic Treaty Organization, this round is exceptionally popular. However, recent mass shootings have employed soft point (SP) expanding ammunition to cause grievous wounds compared with military full metal jacket (FMJ) rounds that do not rapidly expand on impact.

Methods

The aim of this given study is to compare FMJ and SP rounds to determine if there are diagnostic differences between the bullet types in the wounds inflicted to flat bones.Bos taurusscapulae were used for 25 m simulated cranial gunshot injuries. Scanning electron microscopy was employed to assess the difference in wound morphology and elemental analysis between SP and FMJ rounds.

Results

Entrance and exit wound morphology change significantly between the two different types of ammunition as seen with circumferential delamination which is indicative of FMJ rounds and is not seen with the softer SP hunting rounds. Lead staining of the entrance wound is visible on only the SP rounds.

Conclusion

Gunshot flat bone wound morphology is distinctively different between SP and FMJ rounds. Circumferential delamination is only seen with FMJ due to the hardness of the round. Lead staining is only seen with SP rounds due to bullet composition.
Are new vision standards and tests needed for military aircrew using 3D stereo helmet-mounted displays?
Authors: Posselt Bonnie Noeleen , Winterbottom M
Published: May 2020

Visual standards for military aviators were historically set in the 1920s with requirements based on the visual systems of aircraft at the time, and these standards have changed very little despite significant advances in aircraft technology. Helmet-mounted displays (HMDs) today enable pilots to keep their head out of the cockpit while flying and can be monocular, biocular or binocular in design. With next generation binocular HMDs, flight data can be displayed in three-dimensional stereo to declutter information presented, improving search times and potentially improve overall performance further. However, these new visually demanding technologies place previously unconsidered stresses on the human visual system. As such, new medical vision standards may be required for military aircrew along with improved testing methods to accurately characterise stereo acuity.
Has the introduction of direct oral anticoagulants (DOACs) in England increased emergency admissions for bleeding conditions? A longitudinal ecological study
Authors: Alfirevic Ana , Downing Jennifer , Daras Konstantinos , Comerford Terence , Pirmohamed Munir , Barr Ben
Published: May 2020

Objective

There is concern about long-term safety of direct oral coagulants (DOACs) in clinical practice. Our aim was to investigate whether the introduction of DOACs compared with vitamin-K antagonists in England was associated with a change in admissions for bleeding or thromboembolic complications.

Setting

5508 General practitioner (GP) practices in England between 2011 and 2016.

Participants

All GP practices in England with a registered population size of greater than 1000 that had data for all 6 years.

Main outcome measure

The rate of emergency admissions to hospital for bleeding or thromboembolism, per 100 000 population for each GP practice in England.

Main exposure measure

The annual number of DOAC items prescribed for each GP practice population as a proportion of all anticoagulant items prescribed.

Design

This longitudinal ecological study used panel regression models to investigate the association between trends in DOAC prescribing within GP practice populations and trends in emergency admission rates for bleeding and thromboembolic conditions, while controlling for confounders.

Results

For each additional 10% of DOACs prescribed as a proportion of all anticoagulants, there was a 0.9% increase in bleeding complications (rate ratio 1.008 95% CI 1.003 to 1.013). The introduction of DOACs between 2011 and 2016 was associated with additional 4929 (95% CI 2489 to 7370) emergency admissions for bleeding complications. Increased DOAC prescribing was associated with a slight decline in admission for thromboembolic conditions.

Conclusion

Our data show that the rapid increase in prescribing of DOACs after changes in National Institute for Health and Care Excellence guidelines in 2014 may have been associated with a higher rate of emergency admissions for bleeding conditions. These consequences need to be considered in assessing the benefits and costs of the widespread use of DOACs.
Historical database cohort study addressing the clinical patterns prior to idiopathic pulmonary fibrosis (IPF) diagnosis in UK primary care
Authors: Thickett David , Voorham Jaco , Ryan Ronan , Jones Rupert , Coker Robina , Wilson Andrew M , Yang Sen , Ow Mandy YL , Raju Priyanka , Chaudhry Isha , Hardjojo Antony , Carter Victoria , Price David B
Published: May 2020

Objective

To explore the clinical pathways, including signs and symptoms, and symptom progression patterns preceding idiopathic pulmonary fibrosis (IPF) diagnosis.

Design and setting

A historical cohort study was conducted using primary care patient records from the Optimum Patient Care Research Database.

Participants

Patients included were at least 30 years, had IPF diagnosis, identified via clinical-coding and free-text records and had a consultation with a chest specialist prior to IPF diagnosis.

Outcome measures

The signs and symptoms in the year prior to IPF diagnosis from clinical codes and free-text in primary care electronic records included: cough, dyspnoea, dry cough, weight loss, fatigue/malaise, loss of appetite, crackles and clubbed fingers. The time course of presentations of clinical features and investigations in the years prior to IPF diagnosis were mapped.

Results

Within 462 patients identified, the majority (77.9%) had a respiratory consultation within 365 days prior to the chest specialist visit preceding the IPF diagnosis recorded in their primary care records. The most common symptoms recorded in the 1 year prior to IPF diagnosis were dyspnoea (48.7%) and cough (40.9%); other signs and symptoms were rarely recorded (<5%). The majority of patients with cough (58.0%) and dyspnoea (55.0%) in the 1 year before IPF diagnosis had multiple recordings of the respective symptoms. Both cough and dyspnoea were recorded in 23.4% of patients in the year prior to diagnosis. Consultation rates for cough, dyspnoea and both, but not other signs or symptoms, began to increase 4 to 5 years prior diagnosis, with the sharpest increase in the last year. Cough and dyspnoea were often preceded by a reduction in measured weight over 5 years leading to IPF diagnosis.

Conclusion

Prolonged cough and/or progressive dyspnoea, especially if accompanied with weight loss, should signal for a referral to specialist assessment at the earliest opportunity.
Characteristics and interpretation of subgroup analyses based on tumour characteristics in randomised trials testing target-specific anticancer drugs: design of a systematic survey
Authors: Schandelmaier Stefan , Schmitt Andreas M , Herbrand Amanda K , Glinz Dominik , Ewald Hannah , Briel Matthias , Guyatt Gordon H , Hemkens Lars G , Kasenda Benjamin
Published: May 2020

Background

Target-specific anticancer drugs are under rapid development. Little is known, however, about the risk of administering target-specific drugs to patients who have tumours with molecular alterations or other characteristics that can make the drug ineffective or even harmful. An increasing number of randomised clinical trials (RCTs) investigating target-specific anticancer drugs include subgroup analyses based on tumour characteristics. Such subgroup analyses have the potential to be more credible and influential than subgroup analyses based on traditional factors such as sex or tumour stage. In addition, they may more frequently lead to qualitative subgroup effects, that is, show benefit in one but harm in another subgroup of patients (eg, if the tumour characteristic makes the drug ineffective or even enhance tumour growth). If so, subgroup analyses based on tumour characteristics would be highly relevant for patient safety. The aim of this study is to systematically assess the frequency and characteristics of subgroup analyses based on tumour characteristics, the frequency of qualitative subgroup effects, their credibility, and the interpretations that investigators and guidelines developers report.

Methods and analysis

We will perform a systematic survey of 433 RCTs testing the effect of target-specific anticancer drugs. Teams of methodologically trained investigators and oncologists will identify eligible studies, extract relevant data and assess the credibility of putative subgroup effects using a recently developed formal instrument. We will systematically assess how trial investigators interpret apparent subgroup effects based on tumour characteristics and the extent to which they influence subsequent practice guidelines. Our results will provide empirical data characterising an increasingly used type of subgroup analysis in cancer trials and its potential impact on precision medicine to predict benefit or harm.

Ethics and dissemination

Formal ethical approval is not required for this study. We will disseminate the findings in a peer-reviewed and open-access journal publication.
Study protocol to examine the relationship between environmental exposure to lead and blood lead levels among children from day-care centres in Ekurhuleni Metropolitan Municipality
Authors: Cindi Mbalenhle Desiree , Mbonane Thokozani Patrick , Naicker Nisha
Published: May 2020

Introduction

Lead exposure is toxic to all humans and is very harmful to young children, especially 5-year-olds. Elevated blood lead levels (BLLs) in children have been associated with their daily surrounding environment. This protocol seeks to evaluate the association between environmental lead exposure and BLLs among children in day-care centres, including household and other risk factors.

Methods and analysis

To achieve the objectives of the study, we adopted a cross-sectional analytical design. A portable X-ray fluorescence analyser was used for environmental sampling, and BLLs were determined using the LeadCare II machine among preschool children. Household and other risk factors were assessed using a questionnaire. Random sampling was employed to select day-care centres in the municipality and children in each day-care centre. Data will be analysed using SPSS V. 26.

Ethics and dissemination

Ethical approval and permission were obtained prior to commencement of the study. The researcher intends to publish the results in peer-reviewed journals and also to present a paper at a scientific conference. The study will generate information on environmental lead exposure among vulnerable children (2–5 years), and it will promote public health action to prevent long-term exposure in day-care centres.
Data-sharing recommendations in biomedical journals and randomised controlled trials: an audit of journals following the ICMJE recommendations
Authors: Siebert Maximilian , Gaba Jeanne Fabiola , Caquelin Laura , Gouraud Henri , Dupuy Alain , Moher David , Naudet Florian
Published: May 2020

Objective

To explore the implementation of the International Committee of Medical Journal Editors (ICMJE) data-sharing policy which came into force on 1 July 2018 by ICMJE-member journals and by ICMJE-affiliated journals declaring they follow the ICMJE recommendations.

Design

A cross-sectional survey of data-sharing policies in 2018 on journal websites and in data-sharing statements in randomised controlled trials (RCTs).

Setting

ICMJE website; PubMed/Medline.

Eligibility criteria

ICMJE-member journals and 489 ICMJE-affiliated journals that published an RCT in 2018, had an accessible online website and were not considered as predatory journals according to Beall’s list. One hundred RCTs for member journals and 100 RCTs for affiliated journals with a data-sharing policy, submitted after 1 July 2018.

Main outcome measures

The primary outcome for the policies was the existence of a data-sharing policy (explicit data-sharing policy, no data-sharing policy, policy merely referring to ICMJE recommendations) as reported on the journal website, especially in the instructions for authors. For RCTs, our primary outcome was the intention to share individual participant data set out in the data-sharing statement.

Results

Eight (out of 14; 57%) member journals had an explicit data-sharing policy on their website (three were more stringent than the ICMJE requirements, one was less demanding and four were compliant), five (35%) additional journals stated that they followed the ICMJE requirements, and one (8%) had no policy online. In RCTs published in these journals, there were data-sharing statements in 98 out of 100, with expressed intention to share individual patient data reaching 77 out of 100 (77%; 95% CI 67% to 85%). One hundred and forty-five (out of 489) ICMJE-affiliated journals (30%; 26% to 34%) had an explicit data-sharing policy on their website (11 were more stringent than the ICMJE requirements, 85 were less demanding and 49 were compliant) and 276 (56%; 52% to 61%) merely referred to the ICMJE requirements. In RCTs published in affiliated journals with an explicit data-sharing policy, data-sharing statements were rare (25%), and expressed intentions to share data were found in 22% (15% to 32%).

Conclusion

The implementation of ICMJE data-sharing requirements in online journal policies was suboptimal for ICMJE-member journals and poor for ICMJE-affiliated journals. The implementation of the policy was good in member journals and of concern for affiliated journals. We suggest the conduct of continuous audits of medical journal data-sharing policies in the future.

Registration

The protocol was registered before the start of the research on the Open Science Framework (https://osf.io/n6whd/).
Remarkably high prevalence of overuse-related knee complaints and MRI abnormalities in youth competitive alpine skiers: a descriptive investigation in 108 athletes aged 13–15 years
Authors: Fröhlich Stefan , Peterhans Loris , Stern Christoph , Frey Walter O , Sutter Reto , Spörri Jörg
Published: May 2020

Background/aim

Competitive alpine skiing is known to be associated with a high risk of traumatic knee injuries. However, little is known about the exact prevalence of knee overuse injuries and their associations with structural changes, particularly in youth skiers. Accordingly, the aim of the present study was to describe the overuse-related knee complaints and MRI abnormalities in a cohort of youth skiers around the growth spurt.

Methods

108 youth competitive alpine skiers aged 13–15 years were examined using an MRI of both knees, an interview on existing knee complaints and a physical examination. As a common baseline for these assessments, skiers were prospectively monitored by the use of the Oslo Sports Trauma Research Centre questionnaire on health problems over a period of 12 months preceding the major investigations.

Results

88.0% of the youth skiers showed at least one MRI abnormality in the knees. The most frequent findings were distal femoral cortical irregularities (63%), focal periphyseal oedema (FOPE) zones (25.0%) and cartilage lesions (18.5%). 47.2% of all skiers suffered from at least one overuse-related knee complaint during the 12 months preceding the MRI examination, mostly at the distal and proximal patellar tendon. However, despite a certain association with corresponding MRI abnormalities, the sensitivity of an MRI-based detection of such complaints was strongly limited.

Conclusion

Youth competitive alpine skiers suffer from a remarkably large number of knee overuse injuries. Accordingly, an effective prevention strategy should include a systematic screening of clinical complaints, ideally already starting around the growth spurt.
Inflammatory bowel disease and risk of small bowel cancer: a binational population-based cohort study from Denmark and Sweden
Authors: Axelrad Jordan E , Olén Ola , Sachs Michael C , Erichsen Rune , Pedersen Lars , Halfvarson Jonas , Askling Johan , Ekbom Anders , Sørensen Henrik Toft , Ludvigsson Jonas F
Published: May 2020

Objective

Crohn’s disease (CD) is associated with increased risk of small bowel cancer (SBC), but previous studies have been small. We aimed to examine the risk of incident SBC and death from SBC in patients with inflammatory bowel disease (IBD).

Design

In a binational, population-based cohort study from Sweden and Denmark of patients with IBD during 1969–2017 and matched reference individuals from the general population, we evaluated the risk of incident SBC and death from SBC. Cox regression was used to estimate adjusted hazard ratios (aHRs).

Results

We identified 161 896 individuals with IBD (CD: 47 370; UC: 97 515; unclassified IBD: 17 011). During follow-up, 237 cases of SBC were diagnosed in patients with IBD (CD: 24.4/100 000 person-years; UC: 5.88/100 000 person-years), compared with 640 cases in reference individuals (2.81/100 000 person-years and 3.32/100 000 person-years, respectively). This corresponded to one extra case of SBC in 385 patients with CD and one extra case in 500 patients with UC, followed up for 10 years. The aHR for incident SBC was 9.09 (95% CI 7.34 to 11.3) in CD and 1.85 (95% CI 1.43 to 2.39) in UC. Excluding the first year after an IBD diagnosis, the aHRs for incident SBC decreased to 4.96 in CD and 1.69 in UC. Among patients with CD, HRs were independently highest for recently diagnosed, childhood-onset, ileal and stricturing CD. The relative hazard of SBC-related death was increased in both patients with CD (aHR 6.59, 95% CI 4.74 to 9.15) and patients with UC (aHR 1.57; 95% CI 1.07 to 2.32).

Conclusion

SBC and death from SBC were more common in patients with IBD, particularly among patients with CD, although absolute risks were low.