bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinematic Design and Evaluation of a Six-Bar Knee-Ankle-Foot Orthosis
Authors: Ghosh Shramana , Robson Nina P. , McCarthy J. Michael
Published: February 2020

This paper presents a new two-step design procedure and preliminary kinematic evaluation of a novel, passive, six-bar knee-ankle-foot orthosis (KAFO). The kinematic design and preliminary kinematic gait analysis of the KAFO are based on motion capture data from a single healthy male subject. Preliminary kinematic evaluation shows that the designed passive KAFO is capable of supporting flexion and extension of the knee joint during stance and swing phases of walking. The two-step design procedure for the KAFO consists of (1) computational synthesis based on user's motion data and (2) performance optimization. In the computational synthesis step, first the lower leg (knee-ankle-foot) of the subject is approximated as a 2R kinematic chain and its target trajectories are specified from motion capture data. Six-bar linkages are synthesized to coordinate the angular movements of knee and ankle joints of the 2R chain at 11 accuracy points. The first step of the design procedure yields 332 six-bar KAFO design candidates. This is followed by a performance optimization step in which the KAFO design candidates are optimally modified to satisfy specified constraints on end-effector trajectory and shape. This two-step process yields an optimally designed passive six-bar KAFO that shows promising kinematic results at the knee joint of the user during walking. The preliminary prototype manufactured is cost effective, easy to operate, and suitably demonstrates the feasibility of the proposed concept.
Static Nodes of an Axially Moving String With Time-Varying Supports
Authors: Lu Lei , Yang Xiao-Dong , Zhang Wei
Published: February 2020

By investigating the transverse vibrations of an axially moving string with time-varying supports, the existence and the pattern of static nodes are studied based on the assumed mode method and the linear superposition method. The explicit expressions for the response of the system with five different boundary conditions are illustrated. Traditional excited static strings show nodes when resonance occurs. However, it is found in this study that the static nodes of axially moving strings appear under arbitrary frequency even far away from resonance, if the excitation frequency is higher than the fundamental frequency. The varying nodes and frequencies under different time-varying supports are revealed.
Controlling Porosity of Anode Support in Tubular Solid Oxide Fuel Cells by Freeze Casting
Authors: Emley Benjamin , Panthi Dhruba , Du Yanhai , Yao Yan
Published: February 2020

Precise porosity control is highly desirable for improving the electrochemical performance of solid oxide fuel cells (SOFCs). Freeze casting is an established method for enabling high bulk porosity in structures and controlling pore orientation. In this study, freeze casting was used to fabricate tubular, anode-supported SOFCs with aligned and varying amounts of porosity by controlling the solids/water ratio in different casting slurries. SOFCs were prepared with a Ni/yttria and scandia stabilized zirconia (ScYSZ) anode support (AS), an anode functional layer (AFL), a ScYSZ electrolyte, a lanthanum strontium manganite (LSM)/ScYSZ cathode interlayer (CIL), and an LSM cathode. The permeability of the anode support was found to increase from 1.4 × 10−2 to 1.8 × 10−2 m2 as porosity was increased from 57 to 64 vol%, while the total cell resistance decreased by 35% from 0.93 to 0.60 Ohm cm2. When evaluated with 30 vol% H2 as the fuel at 800 °C, the decrease of concentration polarization enabled an increase in electrochemical performance by 42% from 0.35 to 0.50 W/cm2 as the porosity in the anode support was increased. Mechanical strength characterization using a three-point method showed there is a practical upper limit of the amount of porosity that can be designed into the anode support. This work paves a way for controlling porosity by freeze casting and understanding the correlation between porosity and concentration polarization losses in SOFCs.
Influence of Hemodialysis Catheter Insertion on Hemodynamics in the Central Veins
Authors: Park Min-Hyuk , Qiu Yue , Cao Haoyao , Yuan Ding , Li Da , Jiang Yi , Peng Liqing , Zheng Tinghui
Published: February 2020

Central venous catheter (CVC) related thrombosis is a major cause of CVC dysfunction in patients under hemodialysis. The aim of our study was to investigate the impact of CVC insertion on hemodynamics in the central veins and to examine the changes in hemodynamic environments that may be related to thrombus formation due to the implantation of CVC. Patient-specific models of the central veins with and without CVC were reconstructed based on computed tomography images. Flow patterns in the veins were numerically simulated to obtain hemodynamic parameters such as time-averaged wall shear stress (TAWSS), oscillating shear index (OSI), relative residence time (RRT), and normalized transverse wall shear stress (transWSS) under pulsatile flow. The non-Newtonian effects of blood flow were also analyzed using the Casson model. The insertion of CVC caused significant changes in the hemodynamic environment in the central veins. A greater disturbance and increase of velocity were observed in the central veins after the insertion of CVC. As a result, TAWSS and transWSS were markedly increased, but most parts of OSI and RRT decreased. Newtonian assumption of blood flow would overestimate the increase in TAWSS after CVC insertion. High wall shear stress (WSS) and flow disturbance, especially the multidirectionality of the flow, induced by the CVC may be a key factor in initiating thrombosis after CVC insertion. Accordingly, approaches to decrease the flow disturbance during CVC insertion may help restrain the occurrence of thrombosis. More case studies with pre-operative and postoperative modeling and clinical follow-up need to be performed to verify these findings. Non-Newtonian blood flow assumption is recommended in computational fluid dynamics (CFD) simulations of veins with CVCs.
Biomechanical Relationships Between Manual Wheelchair Steering and the Position of the Human Body's Center of Gravity
Authors: Wieczorek B. , Kukla M.
Published: February 2020

The purpose of this investigation was to analyze the impact of differential steering of a wheelchair with a pushrim on changes in the position of the body's center of gravity. The method assumed measuring the wheelchair trajectory and the body's center of gravity and determining the transverse relocation of the measured body's center of gravity in relation to a point on the wheelchair trajectory. Twenty-seven measurement tests which demonstrated various wheelchair trajectories were carried out within the investigation. The trajectories were 10 to 15 m long and involved moving forward (test 2), reversing (test 3), turning left (test 1) and right (test 4). The factor of deviation of the center of gravity of human body from the wheelchair trajectory was determined for selected characteristic turning maneuvers. The measured values ranged from 51 to 192 mm. The impact of the wheelchair trajectory on the position of the body's center of gravity was demonstrated as a result of this investigation. Consequently, a trajectory deviation factor for relocation of the human body weight on one side of the wheelchair has been demonstrated.
Quantification of Passive Ventilation Produced by Manual Chest Compressions Using a New Cardiopulmonary Resuscitation Feedback Device
Authors: Taleb Lhoucine Ben , Essoukaki Elmaati , Mouhsen Azeddine , Lyazidi Aissam , Assir Abdelhadi , Harmouchi Mohammed , Rattal Mourad
Published: February 2020

Several studies have shown that chest compressions (CC) alone may produce in addition to blood circulation, a short-term passive ventilation. However, it is not clear whether high CC quality may produce in even greater amount of ventilation volumes. The aim of this study was to evaluate whether CC, using a new feedback device, can produce a substantial and sustainable passive volumes compared to standard CC. Thirty inexperienced volunteers performed CC for 2 min on a developed thoracic lung model and using a new feedback device. Participants were randomized into two groups that performed either CC with feedback first, followed by a trial without feedback, or vice versa. Efficient compression rate (correct CC rate and depth simultaneously) was significantly higher in feedback session (43.6% versus 25.5%; P = 0.006). As well, CC rate and depth efficiency were improved with feedback. Moreover, average tidal volumes and minute volumes that occurred during CC alone were significantly improved in feedback session (79.8 ± 5 ml versus 72.9 ± 7 ml) and (8.8 l/min versus 7.9 l/min), respectively (P < 0.001). Yet, no significant difference was found between the first and the 90th second interval (9.04 l/min versus 8.68 l/min, P = 0.163) in the feedback session. Conversely, a significant difference was evident after the first 15th seconds interval without feedback (8.77 l/min initially versus 8.38 l/min; P = 0.041). This study revealed that the new CPR feedback device improved CC quality in inexperienced volunteers. As well, the passive ventilation volumes were significantly increased and sustained when the device was used.
The Effect of Isentropic Exponent on Transonic Turbine Performance
Authors: Baumgärtner David , Otter John J. , Wheeler Andrew P. S.
Published: February 2020

The isentropic exponent is one of the most important properties affecting gas dynamics. Nonetheless, its effect on turbine performance is not well known. This paper discusses a series of experimental and computational studies to determine the effect of isentropic exponent on the flow field within a turbine vane. Experiments are performed using a newly modified transient wind tunnel that enables annular cascade testing with a wide range of working fluids and operating conditions. For the present study, tests are undertaken using air, CO2, R134a, and argon, giving a range of isentropic exponent from 1.08 to 1.67. Measurements include detailed wall static pressures that are compared with computational simulations. Our results show that over the range of isentropic exponents tested here, the loss can vary between 20% and 35%, depending on vane exit Mach number. The results are important for future turbines operating with real-gas effects and/or those where high gas temperatures can lead to variations in the isentropic exponent.
Using a New Entropy Loss Analysis to Assess the Accuracy of RANS Predictions of an High-Pressure Turbine Vane
Authors: Zhao Yaomin , Sandberg Richard D.
Published: February 2020

Entropy loss is widely used to quantify the efficiency of components in turbomachines, and empirical relations have been developed to estimate the contribution of different mechanisms. However, further analysis is still needed to not only get a deeper insight of the physics but also to more accurately quantify the loss generation caused by different terms. In the present study, the entropy transport equations based on averaged flow quantities are first derived, and the entropy generation process is fully decomposed into several terms representing different physical mechanisms, such as mean viscous dissipation, turbulence production, mean, and turbulent heat flux, etc. This decomposition framework is then applied to high-resolution large-eddy simulation (LES) and Reynolds-averaged Navier–Stokes (RANS) results of a VKI LS-89 HPT vane, and a detailed quantification of different entropy generation terms is obtained. The results show that the entropy generation caused by mean flow features like mean viscous dissipation and mean heat flux are in close agreement between LES and RANS, indicating that RANS provides an overall good prediction for the mean flow. Furthermore, we find that turbulence production plays an important role in entropy generation as it represents the energy extracted from the mean flow to turbulent fluctuations. However, the difference between RANS and LES results for the turbulence production term is not negligible, particularly in the wake region. This implies that the failure of RANS to predict the correct total loss might be largely caused by errors in capturing the correct turbulence production in the near wake region.
Predicting Multi-Order Magnetic Polaritons Resonance in SiC Slit Arrays by Mutual Inductor–Inductor–Capacitor Circuit Model
Authors: Guo Yanming , Xiong Bo , Shuai Yong
Published: February 2020

Magnetic polariton (MP) that couples electromagnetic waves with magnetic excitation can be predicted by equivalent inductor–capacitor (LC) circuit model. However, when the resonance frequencies of MP and surface phonon polariton (SPhP) is close, the absorption and transmission peaks predicted by LC circuit model are far different from solving electromagnetic field calculation results. In this work, absorption and transmission enhancements with a SiC slit array are theoretically demonstrated within the SiC phonon absorption band with finite difference time-domain (FDTD) method. The interactions between SPhP and MP are confirmed by electromagnetic field distributions. Mutual inductor–inductor–capacitor (MLC) circuit model is used to predict the multiorder MP resonance conditions, and the coupling between MP and SPhP is treated as a mutual inductor in MLC model. The geometric effects of SiC slit arrays are investigated and MLC circuit model works well. This study may contribute to the design and prediction of thermal radiative properties and micro-/nanostructure metamaterials thermal radiative properties database building.
Nonlinear Analysis of Effect of Rigid Body Rotation on Ferroconvection
Authors: Melson Anthony Christy , Sekhar G. N. , Siddheshwar P. G.
Published: February 2020

The paper presents a numerical study of the effect of rotation on convection and heat transport in ferromagnetic liquids. The conditions for validity of principle of exchange of stabilities have been identified by means of linear stability analysis. The nonlinear stability analysis has been done using the streamline formulation. The systems of equations derived with the help of minimal Fourier series representation are analogous to those of the Lorenz model. The effect of different parameters on heat transport has been quantified through the average Nusselt number obtained from the solution of the scaled Lorenz model. Certain unusual effects of buoyancy magnetic parameter and nonbuoyancy magnetic parameter on heat transport are reported.
Unsteady Laminar Pulsating Flow in a Saturated Porous Microchannel in the Presence of Electrical Double-Layer Effects
Authors: Niazi Muhammad Dilawar Khan , Xu Hang
Published: February 2020

The forced convection of a pulsating flow in a saturated porous parallel-plates microchannel driven by a periodic pressure in the presence of an electrical double layer is investigated. Such configuration is very important but seldom considered in literature. Analytical solutions for electrical, momentum, and temperature fields are obtained by means of a substitution approach. The results show that the flow fields depend highly on the electro-osmotic parameter κ, the angular velocity parameter Ω, as well as the Darcy number Da.
New Approach of Triumphing Temperature Nonuniformity and Heat Transfer Performance Augmentation in Micro Pin Fin Heat Sinks
Authors: Kumar Ritunesh , Abiev Rufat , Ribatski Gherhardt , Abdullah Shekh , Vasilev Maksim
Published: February 2020

This study is the first part of the development of improved micro pin fin heat sink (MPFHS) for the thermal management of modern microprocessor chip cooling. In the current numerical study, a new fluid flow distribution scheme for MPFHS has been proposed for triumphing over surface temperature nonuniformity problem—one of the most critical issues interfering with the thermal management of modern microprocessors chip cooling. It is established that fluid, if supplied from the confronting sides (front/side directions) of the MPFHS, helps in mitigating temperature nonuniformity and intensifies heat transfer rate. Fluid starts enjoying following paybacks on account of proposed change: the benefits of the developing flow even in adverse temperature zones of the conventional design, enriched secondary channels fluid flow, and rigorous mixing of the cooling fluid between the primary and the secondary channels. Two front facing multi-inlet designs (MPFHSMI,F and MPFHSMI,FH) and one side facing multi-inlet design (MPFHSMI,SH) are conceptualized and compared with the conventional design MPFHSCD. Base surface temperature nonuniformity reduces 7.6 °C, 24 °C, and 7.4 °C by the MPFHSMI,F, MPFHSMI,FH, and MPFHSMI,SH designs, respectively. Average Nusselt number for the cases MPFHSMI,F, MPFHSMI,FH, and MPFHSMI,SH is found 26.7%, 52.3%, and 70.9% higher than the conventional design of MPFHS. Overall thermal performance factor of one design MPFHSMI,FH is found 1.66 at the applied heat flux of 125 W/cm2.
Design and development of field emission based magnetron for industrial applications using conformal finite-difference time-domain particle-in-cell simulations
Authors: Li Ling , Aranganadin Kaviya , Hsu Hua-Yi , Lin Ming-Chieh
Published: February 2020

The magnetron is a high-efficiency high-power vacuum tube that generates microwaves based on the interaction of a stream of moving electrons under crossed electric and magnetic fields with a series of open coupled cavity resonators. They are widely used as a low-cost microwave source for industrial heating. Traditionally, a thermionic cathode is used as the electron source and a heater is needed to increase the temperature of the cathode up to about 1000 K. In this work, a field emission-based magnetron has been investigated for industrial applications as an easier and more robust configuration. The design and development were performed using a conformal finite-difference time-domain particle-in-cell simulation as implemented in the VSim code. A rising-sun configuration has been optimized and the corresponding operating condition has been determined to achieve an efficiency of up to ∼80%. The rising-sun magnetron operating at a frequency of 2.45 GHz can give an output power of 3 kW, serving as a good replacement of existing industrial magnetrons.
Exercise Time and Intensity: How Much Is Too Much?
Authors: Gottschall Jinger S. , Davis Joshua J. , Hastings Bryce , Porter Heather J.
Published: February 2020

The growing prevalence and popularity of interval training necessitate additional guidelines in regard to maximal levels of time and intensity. Purpose: To correlate salivary hormones and time in varying heart-rate (HR) zones. The hypothesis was that chronic exercise durations >9% of total exercise time in the >90% maximum HR zone would lead to decreased variation in salivary cortisol concentration after exercise in a 2-bout high-intensity protocol compared with less or more time in this zone. Methods: A total of 35 healthy adults who regularly exercised for an average of 8 hours per week recorded their HR during every training session for 3 weeks. Later, they completed an experimental day composed of two 30-minute high-intensity interval sessions separated by 4 hours of nonactive recovery. The authors collected saliva samples before, immediately following, and 30 minutes after each exercise session to assess changes in cortisol concentrations. Results: There was a correlation between weekly time training at an intensity >90% maximum HR and the variables associated with overtraining. Salivary cortisol concentration fluctuated less in the participants who exercised in this extreme zone for >40 minutes per week (P < .001). Conclusion: Based on the current study data, for individuals who regularly exercise, 4% to 9% total training time above 90% maximum HR is the ideal duration to maximize fitness and minimize symptoms related to overreaching.
Factors Influencing Concussion Reporting Intention in Adolescent Athletes
Authors: Cook Natalie , Hunt Tamerah N.
Published: February 2020

Clinical Scenario: Concussions are severely underreported, with only 47.3% of high school athletes reporting their concussion. The belief was that athletes who were better educated on the signs and symptoms and potential dangers of concussion would be more likely to report. However, literature has shown inconsistent evidence on the efficacy of concussion education, improving reporting behaviors. Factors such as an athlete’s attitude, subjective norms, and perceived behavioral control have shown promise in predicting intention to report concussions in athletes. Focused Clinical Question: Do attitudes, subjective norms, and perceived behavioral control influence adolescent athletes’ intention to report? Summary of Key Findings: Three studies (1 randomized control and 2 cross-sectional surveys) were included. Across the 3 studies, attitudes, subjective norms, and perceived behavioral control positively influenced athletes’ reporting intention. The studies found that attitude toward concussion reporting and perceived behavioral control were the most influential predictors of reporting intention. Clinical Bottom Line: There is moderate evidence to suggest that positive attitudes, supportive subjective norms, and increased perceived behavioral control influence reporting intention in secondary school athletes. Strength of Recommendation: Grade B evidence exists that positive attitudes, supportive subjective norms, and increased perceived behavioral control positively influence concussion reporting intention in secondary school athletes.
Using the Larry Nassar Case to Create a Coach Education Module to Prompt Social Change
Authors: Fisher Leslee A.
Published: February 2020

The purpose of this paper is to demonstrate how case study methodology, an advocacy practice and policy model (APPM), and new directions in feminist theory can be utilized to educate coaches about sexual misconduct. Case studies are useful for both research and teaching purposes because they provide a potential framework for analyses of “real-world” problems. The APPM provides guidance on moving from analysis to action; in particular, advocacy is about education, negotiation, and persuasion. Feminist theorists push us to consider how the embodied experiences of female athletes and feminine subjectivities can unsettle and disrupt normative assumptions about the way that sport should be conducted. The case of Larry Nassar is utilized because of the amount of reporting available to analyze; this includes female athlete survivor voices. Having coaches wrestle with such questions as (a) Do I know the definitions of sexual misconduct? (b) Do I understand the warning signs a female athlete might be displaying if she is being abused by significant other in sport? (c) When do I have to report abuse to authorities? and (d) Do I know how to intervene on the athlete’s behalf? is important if we are to increase the likelihood of creating systemic change.
Preprints bring ‘firehose’ of outbreak data
Authors: Kupferschmidt Kai
Published: February 2020

COVID-19 has upended the ways researchers share findings and collaborate.
Satellite megaconstellations menace giant survey telescope
Authors: Clery Daniel
Published: February 2020

Darkening the orbiters could limit damaging light trails in wide-field images from the Vera C. Rubin Observatory.
The arrival of strangers
Authors: Wade Lizzie
Published: February 2020

New evidence points to a clash between two ancient Mesoamerican cultures, Teotihuacan and the Maya.
AAAS President Claire Fraser begins a year-long term
Authors: Hoy Anne Q.
Published: February 2020

Fraser offers AAAS a career driven by curiosity, collaboration, and discovery
Ecologically diverse clades dominate the oceans via extinction resistance
Authors: Knope Matthew L. , Bush Andrew M. , Frishkoff Luke O. , Heim Noel A. , Payne Jonathan L.
Published: February 2020

Resisting extinction

Prevailing evolutionary wisdom tells us that ecological differentiation leads to speciation. Whether this pattern can be seen over paleontological time, however, has been difficult to test. Knope
et al.
looked at a dataset of thousands of modern and extinct marine groups and found the relationship to be more complex than expected. Ecological diversification is associated with lower rates of origination, and the taxonomical richness seemingly associated with these groups is due to resistance to extinction. Furthermore, the researchers found that the strong association between ecological differentiation and taxonomic diversity is a recent development shaped by extinction events over time.

Science
, this issue p.
1035
Ultrafast control of vortex microlasers
Authors: Huang Can , Zhang Chen , Xiao Shumin , Wang Yuhan , Fan Yubin , Liu Yilin , Zhang Nan , Qu Geyang , Ji Hongjun , Han Jiecai , Ge Li , Kivshar Yuri , Song Qinghai
Published: February 2020

Ultrafast vortex microlasers

For applications in ultrafast communication, all-optical switches will require low energy consumption, high speed, a strong modulation ratio, a small footprint, and on-chip integration. Although the small footprint and on-chip integration are accessible, the trade-off between low energy consumption and high speed has been challenging. Huang
et al.
exploited the idea of bound states in the continuum, effectively a high–quality (
Q
) cavity without the physical cavity, to design vortex lasers with highly directional output and single-mode operation. With the trade-off between low energy consumption and high speed now broken, it should be possible to realize ultrafast optical switching that meets all the requirements of modern classic and quantum information.

Science
, this issue p.
1018
Bacterial Glycogen Provides Short-Term Benefits in Changing Environments
Authors: Sekar Karthik , Linker Stephanie M. , Nguyen Jen , Grünhagen Alix , Stocker Roman , Sauer Uwe
Published: February 2020

Nothing is constant in life, and microbes in particular have to adapt to frequent and rapid environmental changes. Here, we used real-time metabolomics and single-cell imaging to demonstrate that the internal storage polymer glycogen plays a crucial role in such dynamic adaptations. Glycogen is depleted within minutes of glucose starvation and similarly is replenished within minutes of glucose availability. Cells capable of utilizing glycogen exhibited shorter lag times than glycogen mutants when starved between periods of exposure to different carbon sources. While wild-type and mutant strains exhibited comparable growth rates in steady environments, mutants deficient in glycogen utilization grew more poorly in environments that fluctuated on minute scales between carbon availability and starvation. These results highlight an underappreciated role of glycogen in rapidly providing carbon and energy in changing environments, thereby increasing survival and competition capabilities under fluctuating and nutrient-poor conditions.
Clinical conundrum: status epilepticus culminating into acute dystonia myoclonus
Authors: Khilari Madhuri Laxman , Sharma Praveen Kumar
Published: February 2020

A 7-year-old child who suffered from symptomatic focal epilepsy as a sequel to perinatal hypoxia used to have frequent seizures. This time she developed prolonged status epilepticus lasting for over 5 hours. She received a treatment in the form of intravenous midazolam and reinitiation of sodium valproate and clobazam that were discontinued previously. Seizures were controlled over a couple of hours, but she remained unresponsive. Later, she developed acute onset dystonia (day 3 post-status epilepticus) and also myoclonic jerks. She presented to us after 3 weeks of onset of these complaints and we considered hypoxic encephalopathy resulting from prolonged status epilepticus or acute encephalitis or non-convulsive status epilepticus. However, acute onset dystonia and periodicity of myoclonic jerks were pointers against it, and on evaluation, she was diagnosed with atypical fulminant subacute sclerosing panencephalitis (SSPE). Knowing the atypical presentations of SSPE is important in planning management and prognostication.
Usefulness of data augmentation for visual field trend analyses in patients with glaucoma
Authors: Asaoka Ryo , Murata Hiroshi , Matsuura Masato , Fujino Yuri , Miki Atsuya , Tanito Masaki , Mizoue Shiro , Mori Kazuhiko , Suzuki Katsuyoshi , Yamashita Takehiro , Kashiwagi Kenji , Shoji Nobuyuki
Published: February 2020

Aim

To investigate the usefulness of data augmentation in visual field (VF) trend analyses in patients with glaucoma.

Method

This study included 6380 VFs from 638 eyes of 417 patients with open-angle glaucoma. Various affine transformations were applied to augment the VF data: (1) rotation, (2) scaling, (3) vertical and horizontal shift and (4) a combination of these different transformations. Using pointwise linear regression (PLR), the total deviation (TD) values of a patient’s 10th VF were predicted using TD values from shorter VF series (from first to third VFs (VF1–3) to first to ninth VFs (VF1–9)) with and without VF data augmentation, and the root mean squared error (RMSE) was calculated.

Results

With PLR, mean RMSE without VF augmentation averaged from 3.95 (VF1–3) to 19.01 (VF1–9) dB. The RMSE was significantly improved by applying the different transformations: (1) rotation (from VF1–3 to VF1–7), (2) scaling (from VF1–3 to VF1–6), (3) vertical and horizontal shifts (from VF1–3 to VF1–4) and (iv) a combination of these (from VF1–3 to VF1–7). Progression rates in VF1–10 had better agreement with those in shorter VF series when a combination of affine transformation was applied. The differences in rates were between 1.9 (VF1–3) and 0.39 (VF1–9) dB if augmentation was used, which was significantly smaller than that observed when augmentation was not applied (from 2.6 with VF1–3 to 0.26 dB with VF1–9).

Conclusion

It is useful to apply VF data augmentation techniques when predicting future VF progression in glaucoma using PLR, especially with short VF series.
Maternal and paternal exercise regulate offspring metabolic health and beta cell phenotype
Authors: Zheng Jia , Alves-Wagner Ana Barbara , Stanford Kristin I , Prince Noah B , So Kawai , Mul Joram D , Dirice Ercument , Hirshman Michael F , Kulkarni Rohit N , Goodyear Laurie J
Published: February 2020

Objective

Poor maternal and paternal environments increase the risk for obesity and diabetes in offspring, whereas maternal and paternal exercise in mice can improve offspring metabolic health. We determined the effects of combined maternal and paternal exercise on offspring health and the effects of parental exercise on offspring pancreas phenotype, a major tissue regulating glucose homeostasis.

Research design and methods

Breeders were high fat fed and housed±running wheels before breeding (males) and before and during gestation (females). Offspring groups were: both parents sedentary (Sed); maternal exercise only (Mat Ex); paternal exercise only (Pat Ex); and maternal+paternal exercise (Mat+Pat Ex). Offspring were sedentary, chow fed, and studied at weaning, 12, 20 and 52 weeks.

Results

While there was no effect of parental exercise on glucose tolerance at younger ages, at 52 weeks, offspring of Mat Ex, Pat Ex and Mat+Pat Ex displayed lower glycemia and improved glucose tolerance. The greatest effects were in offspring from parents that both exercised (Mat+Pat Ex). Offspring from Mat Ex, Pat Ex, and Mat+Pat Ex had decreased beta cell size, whereas islet size and beta cell mass only decreased in Mat+Pat Ex offspring.

Conclusions

Maternal and paternal exercise have additive effects to improve glucose tolerance in offspring as they age, accompanied by changes in the offspring endocrine pancreas. These findings have important implications for the prevention and treatment of type 2 diabetes.
How antibiotics are used in pig farming: a mixed-methods study of pig farmers, feed mills and veterinarians in Thailand
Authors: Lekagul Angkana , Tangcharoensathien Viroj , Mills Anne , Rushton Jonathan , Yeung Shunmay
Published: February 2020

Background

Rising global concern about antimicrobial resistance has drawn attention to the use of antibiotics in livestock. Understanding the current usage of antibiotics in these animals is essential for effective interventions on the optimisation of antibiotic use. However, to date few studies have been conducted in low- and middle-income countries. This study aimed to explore the use of antibiotics and estimate the total amount of antibiotics used in pig production in Thailand.

Methods

This was a mixed-methods study including a cross-sectional questionnaire-based survey of 84 pig farmers, secondary analysis of data from a survey of 31 feed mills to estimate the amount of antibiotics mixed in pig feed and interviews with five veterinarians involved in the feed mill industry to gain an understanding of medicated feed production.

Findings

Half of the farmers reported using antibiotics for disease prevention. Use was significantly associated with farmers’ experience in raising pigs, farm income, having received advice on animal health and belonging to a farm cooperative. The estimated total amount of active ingredients mixed into medicated feed for pigs for the whole country was 843 tonnes in 2017. Amoxicillin was the most commonly used antibiotic reported by both pig farms and feed mills. The use of Critically Important Antimicrobials including colistin was common, with one-third of farmers reporting their use as oral or as injectable medication, and accounting for nearly two-thirds of antibiotics contained in medicated feed.

Conclusion

A majority of antibiotics used in Thai pig farms belonged to the category of Critically Important Antimicrobials. Progressive restriction in the use of antibiotics in pigs is recommended through using prescriptions to control the distribution of certain antibiotics. The government should strengthen veterinary services to improve access of farmers to animal health advice and explore alternative interventions.
Electronic clinical decision support algorithms incorporating point-of-care diagnostic tests in low-resource settings: a target product profile
Authors: Pellé Karell G , Rambaud-Althaus Clotilde , D'Acremont Valérie , Moran Gretchen , Sampath Rangarajan , Katz Zachary , Moussy Francis G , Mehl Garrett Livingston , Dittrich Sabine
Published: February 2020

Health workers in low-resource settings often lack the support and tools to follow evidence-based clinical recommendations for diagnosing, treating and managing sick patients. Digital technologies, by combining patient health information and point-of-care diagnostics with evidence-based clinical protocols, can help improve the quality of care and the rational use of resources, and save patient lives. A growing number of electronic clinical decision support algorithms (CDSAs) on mobile devices are being developed and piloted without evidence of safety or impact. Here, we present a target product profile (TPP) for CDSAs aimed at guiding preventive or curative consultations in low-resource settings. This document will help align developer and implementer processes and product specifications with the needs of end users, in terms of quality, safety, performance and operational functionality. To identify the characteristics of CDSAs, a multidisciplinary group of experts (academia, industry and policy makers) with expertise in diagnostic and CDSA development and implementation in low-income and middle-income countries were convened to discuss a draft TPP. The TPP was finalised through a Delphi process to facilitate consensus building. An agreement greater than 75% was reached for all 40 TPP characteristics. In general, experts were in overwhelming agreement that, given that CDSAs provide patient management recommendations, the underlying clinical algorithms should be human-interpretable and evidence-based. Whenever possible, the algorithm’s patient management output should take into account pretest disease probabilities and likelihood ratios of clinical and diagnostic predictors. In addition, validation processes should at a minimum show that CDSAs are implementing faithfully the evidence they are based on, and ideally the impact on patient health outcomes. In terms of operational needs, CDSAs should be designed to fit within clinic workflows and function in connectivity-challenged and high-volume settings. Data collected through the tool should conform to local patient privacy regulations and international data standards.
The differential impact of economic recessions on health systems in middle-income settings: a comparative case study of unequal states in Brazil
Authors: Andrietta Lucas Salvador , Levi Maria Luiza , Scheffer Mário C , Alves Maria Teresa Seabra Soares de Britt , Carneiro Alves de Oliveira Bruno Luciano , Russo Giuliano
Published: February 2020

Introduction

Although economic crises are common in low/middle-income countries (LMICs), the evidence of their impact on health systems is still scant. We conducted a comparative case study of Maranhão and São Paulo, two unevenly developed states in Brazil, to explore the health financing and system performance changes brought in by its 2014–2015 economic recession.

Methods

Drawing from economic and health system research literature, we designed a conceptual framework exploring the links between macroeconomic factors, labour markets, demand and supply of health services and system performance. We used data from the National Health Accounts and National Household Sample Survey to examine changes in Brazil’s health spending over the 2010–2018 period. Data from the National Agency of Supplementary Health database and the public health budget information system were employed to compare and contrast health financing and system performance of São Paulo and Maranhão.

Results

Our analysis shows that Brazil’s macroeconomic conditions deteriorated across the board after 2015–2016, with São Paulo’s economy experiencing a wider setback than Maranhão’s. We showed how public health expenditures flattened, while private health insurance expenditures increased due to the recession. Public financing patterns differed across the two states, as health funding in Maranhão continued to grow after the crisis years, as it was propped up by transfers to local governments. While public sector staff and beds per capita in Maranhão were not affected by the crisis, a decrease in public physicians was observed in São Paulo.

Conclusion

Our case study suggests that in a complex heterogeneous system, economic recessions reverberate unequally across its parts, as the effects are mediated by private spending, structure of the market and adjustments in public financing. Policies aimed at mitigating the effects of recessions in LMICs will need to take such differences into account.
Impact of a pilot NHS-funded sore throat test and treat service in community pharmacies on provision and quality of patient care
Authors: Mantzourani Efi , Evans Andrew , Cannings-John Rebecca , Ahmed Haroon , Hood Kerenza , Reid Nicholas , Howe Robin , Williams Emma , Way Cheryl
Published: February 2020

Objective

A National Health Service (NHS)-funded sore throat test and treat (STTT) service was introduced in selected pharmacies in two local health boards in Wales, as an extension to the national pharmacy common ailment scheme. The aim of this study was to evaluate the impact of STTT on provision and quality of patient care, namely antibiotic use, patient safety and general practitioner (GP) consultation rates.

Methods

Secondary analyses of STTT consultation data to describe service outcomes, and routine data to explore changes in antibiotic prescribing and the prevalence of complications. Data were also collected from one GP practice to explore the feasibility of measuring changes in sore throat consultation rates in general practice.

Results

Less than 20% of 1725 consultations resulted in antibiotic supply. The availability of STTT was associated with greater reductions in prescriptions for phenoxymethylpenicillin than in areas where STTT was not available (−3.8% and −3.4%, difference 0.4%). When pharmacy supplies were included, the reductions in the supply of the antibiotic were similar. No increase in the monthly number of incidents of quinsy was detected, and patients were appropriately referred to other healthcare professionals during pharmacy consultations. GP consultation rates since introduction of STTT were found to be lower than the equivalent monthly average since 2014.

Conclusions

Data from the first 5 months of the STTT service suggest that it may have a role in safely rebalancing uncomplicated sore throat management from general practice to community pharmacies while continuing to promote antibiotic stewardship.
Mitochondrial impairment drives intestinal stem cell transition into dysfunctional Paneth cells predicting Crohn’s disease recurrence
Authors: Khaloian Sevana , Rath Eva , Hammoudi Nassim , Gleisinger Elisabeth , Blutke Andreas , Giesbertz Pieter , Berger Emanuel , Metwaly Amira , Waldschmitt Nadine , Allez Matthieu , Haller Dirk
Published: February 2020

Objective

Reduced Paneth cell (PC) numbers are observed in inflammatory bowel diseases and impaired PC function contributes to the ileal pathogenesis of Crohn’s disease (CD). PCs reside in proximity to Lgr5+ intestinal stem cells (ISC) and mitochondria are critical for ISC-renewal and differentiation. Here, we characterise ISC and PC appearance under inflammatory conditions and describe the role of mitochondrial function for ISC niche-maintenance.

Design

Ileal tissue samples from patients with CD, mouse models for mitochondrial dysfunction (Hsp60Δ/ΔISC) and CD-like ileitis (TNFΔARE), and intestinal organoids were used to characterise PCs and ISCs in relation to mitochondrial function.

Results

In patients with CD and TNFΔARE mice, inflammation correlated with reduced numbers of Lysozyme-positive granules in PCs and decreased Lgr5 expression in crypt regions. Disease-associated changes in PC and ISC appearance persisted in non-inflamed tissue regions of patients with CD and predicted the risk of disease recurrence after surgical resection. ISC-specific deletion of Hsp60 and inhibition of mitochondrial respiration linked mitochondrial function to the aberrant PC phenotype. Consistent with reduced stemness in vivo, crypts from inflamed TNFΔARE mice fail to grow into organoids ex vivo. Dichloroacetate-mediated inhibition of glycolysis, forcing cells to shift to mitochondrial respiration, improved ISC niche function and rescued the ability of TNFΔARE mice-derived crypts to form organoids.

Conclusion

We provide evidence that inflammation-associated mitochondrial dysfunction in the intestinal epithelium triggers a metabolic imbalance, causing reduced stemness and acquisition of a dysfunctional PC phenotype. Blocking glycolysis might be a novel drug target to antagonise PC dysfunction in the pathogenesis of CD.
Bile acid composition regulates GPR119-dependent intestinal lipid sensing and food intake regulation in mice
Authors: Higuchi Sei , Ahmad Tiara R , Argueta Donovan A , Perez Pedro A , Zhao Chen , Schwartz Gary J , DiPatrizio Nicholas V , Haeusler Rebecca A
Published: February 2020

Objectives

Lipid mediators in the GI tract regulate satiation and satiety. Bile acids (BAs) regulate the absorption and metabolism of dietary lipid in the intestine, but their effects on lipid-regulated satiation and satiety are completely unknown. Investigating this is challenging because introducing excessive BAs or eliminating BAs strongly impacts GI functions. We used a mouse model (Cyp8b1–/–mice) with normal total BA levels, but alterations in the composition of the BA pool that impact multiple aspects of intestinal lipid metabolism. We tested two hypotheses: BAs affect food intake by (1) regulating production of the bioactive lipid oleoylethanolamide (OEA), which enhances satiety; or (2) regulating the quantity and localisation of hydrolysed fat in small intestine, which controls gastric emptying and satiation.

Design

We evaluated OEA levels, gastric emptying and food intake in wild-type and Cyp8b1–/–mice. We assessed the role of the fat receptor GPR119 in these effects using Gpr119–/–mice.

Results

Cyp8b1–/–mice on a chow diet showed mild hypophagia. Jejunal OEA production was blunted in Cyp8b1–/–mice, thus these data do not support a role for this pathway in the hypophagia of Cyp8b1–/–mice. On the other hand, Cyp8b1 deficiency decreased gastric emptying, and this was dependent on dietary fat. GPR119 deficiency normalised the gastric emptying, gut hormone levels, food intake and body weight of Cyp8b1–/–mice.

Conclusion

BAs regulate gastric emptying and satiation by determining fat-dependent GPR119 activity in distal intestine.
Association of increased duration of legislated paid maternity leave with childhood diarrhoea prevalence in low-income and middle-income countries: difference-in-differences analysis
Authors: Chai Yan , Nandi Arijit , Heymann Jody
Published: February 2020

Background

Diarrhoea is the second-leading infectious cause of death in children younger than age 5 years. The global burden of severe diarrhoeal disease is concentrated in Africa and Southeast Asia, where a significant percentage of the population resides in low-resource settings. We aimed to quantitatively examine whether extending the duration of legislated paid maternity leave affected the prevalence of childhood diarrhoea in low-income and middle-income countries (LMICs).

Methods

We merged longitudinal data measuring national maternity leave policies with information on the prevalence of bloody diarrhoea related to 884 517 live births occurring between 1996 and 2014 in 40 LMICs that participated at least twice in the Demographic and Health Surveys between 2000 and 2015. We used a difference-in-differences approach to compare changes in the percentage of children with bloody diarrhoea across eight countries that lengthened their paid maternity leave policy between 1995 and 2013 to the 32 countries that did not.

Results

The prevalence of bloody diarrhoea in the past 2 weeks was 168 (SD=40) per 10 000 children under 5 years in countries that changed their policies and 136 (SD=15) in countries that did not. A 1-month increase in the legislated duration of paid maternity leave was associated with 61 fewer cases of bloody diarrhoea (95% CI −98.86 to
−
22.86) per 10 000 children under 5 years of age, representing a 36% relative reduction.

Conclusion

Extending the duration of paid maternity leave policy appears to reduce the prevalence of bloody diarrhoea in children under 5 years of age in LMICs.