bluuebunny/crossref_metadata_2025 huggingface dataset:
Tracings of Behavior of Myoblasts Cultured Under Couette Type of Shear Flow Between Parallel Disks
Authors: Hashimoto Shigehiro , Yonezawa Hiroki
Published: October 2021

A cell deforms and migrates on the scaffold under mechanical stimuli in vivo. In this study, a cell with division during shear stress stimulation has been observed in vitro. Before and after division, both migration and deformation of each cell were analyzed. To make a Couette-type shear flow, the medium was sandwiched between parallel disks (the lower stationary culture-disc and the upper rotating disk) with a constant gap. The wall shear stress (1.5 Pa < τ < 2 Pa) on the surface of the lower culture plate was controlled by the rotational speed of the upper disc. Myoblasts (C2C12: mouse myoblast cell line) were used in the test. After cultivation without flow for 24 hours for adhesion of the cells to the lower disk, constant τ was applied to the cells in the incubator for 7 days. The behavior of each cell during shear was tracked by time-lapse images observed by an inverted phase contrast microscope placed in the incubator. Experimental results show that each cell tends to divide after higher activities: deformation and migration. The tendency is remarkable at the shear stress of 1.5 Pa.
Behavior of Cell Passing Through Micro Slit Between Micro Machined Plates
Authors: Hashimoto Shigehiro , Yoshinaka Kiyoshi , Yonezawa Hiroki
Published: October 2021

Deformation of each cell, as it passes through the micro-slit in the flow channel, has been investigated in vitro. A slit with a rectangular cross section (height 10 μm, width 0.4 mm, length 0.1 mm) was made in the center of the flow path by photolithography technique. Myoblasts (C2C12: mouse myoblast cell line) were used for the test. The flow rate of the medium, in which the cells were suspended, was controlled by a pressure head between the inlet and the outlet. Deformation of each cell passing through the micro-slit was observed with an inverted phase contrast microscope. Using the contour of the image of each cell passing through the slit intermittently, several parameters were analyzed: the two-dimensional projected area, the degree of deformation by ellipse approximation, and the deformation direction. The experimental results show that elongation of the cell in the slit tends to decrease the area of the cell.
Wind Tunnel Experiment on the Aerodynamic Interaction Between Vertical Axis Wind Turbine Pair
Authors: Su Hao , Meng Haoran , Guo Jia , Qu Timing , Lei Liping
Published: October 2021

Wind energy has attracted worldwide attention as a pollution-free and widely distributed renewable energy source. Increasing the power density by optimizing the arrangement of wind turbines has been a popular field of research in recent years. In the present work, a systematic study on the influence of array configuration on vertical axis wind turbines is made through wind tunnel experiments. Firstly, the power performance of an isolated vertical axis wind turbine at different tip speed ratios is tested as a benchmark of comparison. Multiple situations of two-turbine configurations are then tested and the results are compared with the isolated wind turbine. The power coefficient of the turbine pair increases by 34% when the turbines are 2.4 rotor diameters apart and rotate in the same direction. In the counter-rotating co-leeward case, it is demonstrated that the turbine pairs will have a positive effect on each other when they are separated by 2.1 rotor diameters to 2.4 rotor diameters. The lateral spacing between the counter-rotating co-windward turbine pair should be greater than 1.5 rotor diameters to avoid turbulence interference between the rotors.
Vortical Structures and Mixing Characteristics of Flow in Randomly Packed Porous Media During Transition to Turbulence
Authors: Ziazi Reza M. , Liburdy James A.
Published: October 2021

Transition to turbulence in randomly arranged porous media is observed in nature and industrial applications. The flow characteristics of these flows during transition are not well identified. This work describes the parameters influencing on overall mixing during the transition process from the perspective of scale of vortical structures and dispersion characteristics by addressing the following questions: (a) what are the dominant mechanisms evolution of scale of vortices, and (b) how does the inertial effects of vortical structures enhance the flow transport properties through tortuosity and dispersion. Time-resolved PIV is used to investigate the flow in the macro-scale Reynolds numbers from 100 to 1000 to show the pore- versus macro-scale effects on the scale of the flow dispersion, and their contribution in interpreting the overall flow mixing. Lagrangian mixing characteristics based on Eulerian local pore velocity variances is used to demonstrate the bed characteristics for flow in randomly distributed porous media flows. The dispersion asymptotically approaches 0.085 % of VintDH longitudinally which shows the turbulent transport is increased by enhancing the Reynolds number that matches very well with the literature.
Computational Modeling of Planing Hull Dynamics and Slamming in Head Waves
Authors: Matveev Konstantin I.
Published: October 2021

Fast boats often operate in planing regimes when they skim on the water surface and their weight is supported primarily by hydrodynamic forces. In the presence of waves, such hulls may experience large nonlinear motions and hydrodynamic loads, which limit their operational capabilities. To predict hull motions and loads and to optimize the hull shape and structure, one can take advantage of computational fluid dynamics tools that simulate these complex nonlinear flow processes and provide detailed hydrodynamic data, including pressure distribution on the hull and water spray. However, validation of these modeling approaches is needed in order to confidently use numerical tools for the boat design. In this study, numerical modeling is accomplished for dynamics of a realistic hull previously tested in controlled wave environments in towing tanks. Time-domain simulations were first carried out in regular head waves. Mesh-verification studies suggested appropriate numerical grid resolution. The hull’s heave motions, drag forces and bow accelerations were captured and compared with experimental data. The formal validation procedure was applied to confirm suitability of the current numerical approach. In the investigated regular-wave conditions, very pronounced slamming phenomenon was observed, when the hull re-entered water and experienced peak hydrodynamic loads. Pressure distributions on the hull surface and water surface deformations are presented for several time instances around the slamming event. In addition, numerical simulations were also conducted for random waves with statistical sea-wave parameters resembling those of the studied regular waves. The statistical boat responses, such as bow accelerations, heaving motions and drag forces, are compared to the corresponding metrics obtained in regular waves.
Characterizing Surface Roughness Effects on Supersonic Turbulent Boundary Layers
Authors: Zangeneh Rozie
Published: October 2021

Flight vehicles traveling at supersonic or hypersonic speeds are vulnerable to the onset of surface roughness, which can result in changes in the state of the boundary layer, ultimately affecting the performance of the vehicle. While the majority of the wetted surface area of a vehicle is relatively smooth, every vehicle will contain roughness on some level. The concept of similarity between smooth- and rough-wall flows is of great practical importance as most computational and analytical modeling tools rely on it either explicitly or implicitly in predicting flows over rough walls. While a number of important questions have yet to be answered, significant progress has been made in the understanding of flows over rough surfaces in recent years. This paper will be conducting numerical research in rough-wall-bounded turbulent flows in supersonic regimes. Wall-modeled Large Eddy Simulation (WMLES) on a flat plate with various roughness ratios will be conducted at M∞ = 2 to evaluate the boundary layer responses. These responses will be characterized in ensemble averaged mean velocity characteristics as well as turbulent intensity responses through the Reynolds Stresses. The second goal is to characterize the streamwise development of mechanical distortions in the domain. In addition, the near-wall coherent structures will be analyzed to determine the impact of roughness effects. The mean and turbulent statistics scaled by the roughness friction velocity will be compared to other results.
Aerodynamic Performance and Wake Characteristics of a Wind Turbine Model Subjected to Surge and Sway Motions
Authors: Meng Haoran , Su Hao , Guo Jia , Qu Timing , Lei Liping
Published: October 2021

A wind-tunnel experimental study was performed to investigate the impact of the surge and sway motions of a wind turbine model on the power output, rotor thrust and wake characteristics. A wind turbine model was mounted on a translation platform to simulate the surge and sway motions under given amplitude and frequency. The power output and rotor thrust of the turbine model subjected to surge and sway motions were measured by using a DC variable electronic load and a six-component force sensor, respectively. For comparison, these measurements were also performed in a bottom-fixed wind turbine. The results show that the mean power output and mean rotor thrust of the turbine model under surge and sway motions are almost the same as those of the bottom-fixed turbine. However, the thrust fluctuation amplitude of the turbine model under surge motion is significantly higher than those of the turbine model under sway motion and the bottom-fixed turbine. In addition, the wake characteristics of the turbine model were also investigated by using a particle image velocimetry system. The results show that the surge and sway motions have slight effect on the near and intermediate wake of the turbine model in the horizontal plane at the rotor hub height.
Performance Characterization of Hollow Fiber Vacuum Membrane Distillation Module for Desalination
Authors: Caspar Justin , Xue Guanyang , Krysko Robert , Oztekin Alparslan
Published: October 2021

3D laminar flow simulations were conducted using OpenFOAM to resolve the temperature, concentration, velocity, and pressure field for two hollow fiber vacuum membrane distillation configurations with feed solution flowing either inside or outside a single hollow fiber. The fiber has a circular cross-section, a fixed length of 120mm, and an inner diameter of 2 mm. The wall thickness was varied from 150 to 450μm, and the pore diameter was varied from 0.1 to 0.3μm based on commercial fibers. The feed solution is an aqueous solution of water and NaCl. The feed flow was simulated at a Reynolds number of 500 and vacuum pressure of 5,000 Pascals. It was found that there was a 75% increase in flux, from 9.58 to 41.41 kg/m2h, between the worst and the best case in membrane properties. Increasing the pore diameter or wall thickness while the other value was fixed resulted in a 45–57% flux increase depending on the fixed value. The module with the feed solution flowing outside a hollow fiber yields 24% higher flux than the module with the feed solution flowing inside the hollow fiber at the same conditions.
Numerical Investigating of Oscillatory Flow and Heat Transfer Through Stirling Regenerator
Authors: Hachem Houda , Gheith Ramla , Aloui Fethi
Published: October 2021

By developing our proper CFD code under Fortran, the performances of a Stirling engine are studied in unsteady laminar regime and closely linked to the properties of its regenerator. However, it is responsible about the maximum part of losses in the Stirling engine. These losses depend on geometric and physical properties of the material constituting the regenerator. Thus, finding the suitable regenerator material that generates the greatest heat exchange and the lowest pressure drop is a good solution to reduce sources of irreversibility and ameliorate the global performances of the Stirling engine. The aim of this paper is to describe oxillatory flow and heat transfer inside porous regenerator materials and to determine the most suitable regenerator material. Brinkman-Forchheimer-Lapwood extended Darcy model is assumed to simulate momentum transfer within the porous regenerator. And the oscillatory flow is described by the Navier-Stockes compressible equations. The local thermal equilibrium of the gas and the matrix is taken into account for the modelling of the porous regenerator. The governing equations with the appropriate boundary conditions are solved by the control volume based finite element method (CVFEM). A numerical code on the software Fortran is elaborated to evaluate flow and heat transfer characteristics inside regenerator. Results showed that the fluid flow and heat transfer between the compression and expansion phases were varied significantly. It was shown that the superior comprehensive performance of the regenerator makes it possible to improve the performance of Stirling engines.
The CFD Analysis of Cavitation Erosion and Structural Optimization for an Unloading Valve
Authors: Upadhyay Kamal , Yu Rui , Zhou Hua , Yang Huayong
Published: October 2021

The unloading valve is selected as the key part of pressure control and overload protection system in the emulsion pump station (EPS). However, severe cavitation erosion occurs on the inner wall of the valve sleeve located in a downstream outlet, which leads to the performance deterioration, instability, and even failure of the unloading valve. This paper aims to reduce the cavitation phenomenon by optimizing the structure of the spool and improving the streamline direction of the unloading valve. The change in internal structure can reduce cavitation cloud formation along with the internal mechanism of the valve. The working conditions of its flow versus time-dependent data’s are obtained by AMESim, and considered as the boundary condition in Fluent. In addition, the changes in flow behavior and input data’s are analyze and validate before the structural is optimized. After an analysis, the variations in velocities and vapor phase, indicating the higher in pressure drop at its minimum size of valve opening and further consideration for design and development stages. Two innovative structures of valve throttling spool are proposed as a simplified design stage and then carefully curved based on internal geometry to uniformly distribute the velocity vector and streamlines. Subsequently, the post-CFD results reveal the presence of factors affecting properties such as pressure loss, high velocity in the outlets, and concentrated of the vapor volume fraction are decreased under the modified throttling structure and effectively lowers the intensity of cavitation phenomenon.
Influence of the Topological Structures of the Nose of High-Speed Maglev Train on Aerodynamic Performances
Authors: Wang Yeteng , Sun Zhenxu
Published: October 2021

In the past few years, considerable attention has been paid to high-speed maglev train in the field of rail transit. The design speed of the high-speed maglev train is 600km/h, which is significantly higher than that of the high-speed train. With the increase in operating speed, high-speed maglev trains have higher requirements for aerodynamic shape. Superior performance, the beautiful aerodynamic shape is an important direction for the development of high-speed maglev trains. Based on the Vehicle Modeling Function (VMF) method, the current research has developed a parametric shape design method suitable for the aerodynamic shape of the maglev train’s nose. This method can obtain different topological structures of the high-speed maglev train’s nose. The current research uses this method to generate four maglev train noses with large appearance differences and uses these train noses to construct four simplified high-speed maglev models. Then this study numerically analyzes the flow fields of different train models and compares the differences in aerodynamic performance including aerodynamic drag, aerodynamic lift and wake characteristics. The Q-criterion is used to study the vortex structure and mechanism of different train wake regions, and the vortex propagation process is studied by turbulence kinetic energy (TKE). Studying the difference in the aerodynamic force of different topological shapes will help to improve the aerodynamic performance of high-speed maglev trains.
Hybrid MPI-OpenMP Accelerated Euler-Lagrange Simulations of Microbubble Enhanced HIFU
Authors: Ma Jingsen , Deng Xiaolong , Hsiao Chao-Tsung , Chahine Georges L.
Published: October 2021

Microbubble enhanced High Intensity Focused Ultrasound (HIFU) is of great interest to tissue ablation for solid tumor treatments such as in liver and brain cancers, in which contrast agents/microbubbles are injected into the targeted region to promote heating and reduce pre-focal tissue damage. A compressible Euler-Lagrange coupled model has been developed to accurately characterize the acoustic and thermal fields during this process. This employs a compressible Navier-Stokes solver for the ultrasound acoustic field and a discrete singularities model for bubble dynamics.

To address the demanding computational cost in practical biological applications, a multi-level hybrid MPI-OpenMP parallelization scheme is developed to take advantage of both scalability of MPI and load balancing of OpenMP. At the first level, the Eulerian computational domain is divided into multiple subdomains and the bubbles are subdivided in groups based on which subdomain they fall into. At the next level, in each subdomain containing bubbles, multiple OpenMP threads are activated to speed up the bubble computations. More OpenMP threads are used inside each subdomain where the bubbles are clustered. By doing this, MPI load imbalance issue due to non-uniformity of bubble presence is compensated.

The hybrid MPI-OpenMP Euler-Lagrange solver is used to conduct simulations and physical studies of bubble-enhanced HIFU problems containing a large number of microbubbles. The phenomenon of acoustic shadowing caused by the bubble cloud is then analyzed and discussed. Hybrid parallelization efficiency tests and demonstration of its advantages against using MPI alone are presented.
A New RANS Correction to Account for Varying Viscosity Effects
Authors: Coppo Leite Victor , Merzari Elia
Published: October 2021

It has previously been shown that by increasing the Reynolds number across a channel by spatially varying the viscosity does not cause an immediate change in the size of turbulent structures and a delay is in fact observed in both wall shear and friction Reynolds number (Coppo Leite, V, & Merzari, E., Proceedings of the ASME 2020 FEDSM, p. V003T05A019). Furthermore, it is also shown that depending on the length in which the flow condition changes, turbulence bursts are observed in the turbulence field. For the present work we propose a new version of the standard Reynolds Averaged Navier Stokes (RANS) k–τ model that includes some modifications in the production term in order to account for these effects. The new proposed model may be useful for many engineering applications as turbulent flows featuring temperature gradients and high heat transfer rates are often seen in heat exchangers, combustion chambers and nuclear reactors. In these applications, thermal and viscous properties of the working fluid are important design parameters that depend on temperature; hence it is likely to observe strong gradients on these scalars’ fields. To accomplish our goal, the modifications for the k–τ model are implemented and tested for a channel flow with spatial varying viscosity in the streamwise direction. The numerical simulations are performed using Nek5000, a spectral-element code developed at Argonne National Laboratory (ANL). Finally, the results considering a turbulence channel using the proposed model are compared against data obtained using Direct Numerical Simulations from the earlier work.
Statistically Targeted Forcing (STF) Method for Synthetic Turbulence Generation of Initial Conditions in Three-Dimensional Turbulent Mixing Layer Flow
Authors: Shobayo Olalekan O. , Walters D. Keith
Published: October 2021

Computational fluid dynamics (CFD) results are presented for synthetic turbulence generation of initial conditions for the canonical test case of a temporally-developing turbulent mixing layer (TTML) flow. This numerical study investigates the performance of a newly proposed Statistically Targeted Forcing (STF) method, and its capability to act as a restoring force to match the target mean velocity and turbulent stress in a temporally-developing flow where highly unsteady destabilizing mechanisms and influence are evident. Several previous investigations exist documenting vortex dynamics of the turbulent mixing layer, but limited investigations exist on synthetic turbulence generation forcing methods to prescribe initial conditions. The objective of this study is to evaluate the performance of the newly proposed STF method to capture the vortex dynamics and effectively match target mean velocity and resolved turbulent stress predictions using large-eddy simulation. Results are interrogated and compared to statistical velocity and turbulent stress distributions obtained from DNS simulations available in the literature. Results show that the STF method can successfully reproduce desired statistical distributions in a turbulent mixing layer flow.
Analysis of Aeroacoustic Generated From a Rotating Tire With a Longitudinal Groove Using Large-Eddy Simulation
Authors: Asada Kengo , Ito Kimie , Sekimoto Satoshi , Fujii Kozo , Koishi Masataka , Ikeda Toshiyuki
Published: October 2021

Flow fields obtained by large-eddy simulations around a rotating tire with the longitudinal groove are investigated to clarify the relationships between the shape parameters of the grooves and the directivity of aeroacoustic noise and to clarify noise sources. To obtain acoustic field around the rotating tire, the large-eddy simulations using the sixth-order compact finite difference scheme and the tridiagonal filter are performed. The four computational cases including the case without groove are considered in the present study. The proper orthogonal decomposition (POD) analysis revealed the distribution of bipolar modes that spread from the tire to the left and right. This result indicates two symmetrical sound sources near the front of the tire side surface regardless of the presence or absence of the groove shape. It is also found that the presence of grooves in the tire weakens the amplitude of the POD mode that spreads to the left and right. This fact is consistent with the fact that the sound pressure level on the lateral side of the tire weakens as the groove width widens. Based on the observation of the instantaneous field and these analyzes, the following is found. The noise-induced by the flow around the tire considered in the present study is emitted when the turbulent flow generated in front of the tire collides with the tire and flows along the tire’s side surface. Besides, when the tire has a groove, a part of the flow that collides with the tire flows into the groove so that the flow rate flowing on the side surface of the tire decreases and the noise itself also decreases. Therefore, the wider the tire’s groove width, the less noise is emitted from the tire’s lateral side.
Numerical Analysis of Elbow Erosion Mitigation Using Swirl Pipes in Gas-Particle Two-Phase Flows
Authors: Farokhipour A. , Mansoori Z. , Saffar-Avval M. , Ahmadi G.
Published: October 2021

In the oil and gas industry, sand particle erosion damage to elbows is a common problem. The ability to predict erosion patterns is of great importance for sizing lines, analyzing failures, and limiting production rates. Computational fluid dynamics (CFD) can be utilized to study the erosion behavior and mitigate the erosion problem for safety purposes and greater equipment longevity. In order to alleviate the adverse results of sand erosion in elbows, the current study investigated the potential of the geometrically induced swirl flow generated from flow passing through a four-lobed twisted pipe upstream of an elbow. To this end, first, the airflow in a standard elbow equipped with different swirl pipes was simulated using the SIMPLE method, then an Eulerian-Lagrangian approach was employed to track the particles, and finally, the erosion rate was computed. The simulation results indicated that the elbow’s maximum erosion rate with twisted pipes placed upstream of the elbow is lower than the one obtained for the standard pipe. In addition, as the twisted pipe position gets closer to the bend, the erosion rate further reduces. Thus, swirling flows provide a promising prospect as a mechanism to control the erosion rate in elbows.
Modelling Optical Properties of Algae Using the Finite-Difference Time Domain Method
Authors: Samadi Zahra , Johlin Eric , DeGroot Christopher , Peerhossaini Hassan
Published: October 2021

Photosynthetic microorganisms are important to the Earth’s ecosystem, since about half of the atmospheric oxygen is produced by photosynthesis. Microalgae and photosynthetic bacteria are also utilized in a wide range of industries in photobioreactors. In order to have better control over photobioreactors under various operating conditions, it is necessary to accurately characterize the propagation of light in the reactor. Theoretical methods are able to calculate the optical properties of microorganisms through the solution of Maxwell’s equations of electromagnetic wave theory. To solve Maxwell’s equations, various methods can be used including Lorenz-Mie, T-Matrix, Finite-Difference Time-Domain (FDTD), and Volume Integral methods. Most theoretical methods predict the optical properties of microorganisms by Lorenz-Mie theory. Lorenz–Mie theory is applicable for homogeneous and spherical particles, homogeneous concentric spheres, or coated spheres.

This work seeks to determine the suitability of the commonly used homogenous-sphere, coated-sphere, and heterogenous-sphere approximation by simulating the optical behavior of photosynthetic microorganism (Chlamydomonas reinhardtii) using FDTD and an accurate geometric model. Here, each of the key cell organelles will be included in the model with the appropriate optical properties specified. These results allow for a more accurate optical model to be developed while studying the effects of different growth regimes.
REVIEWS OF ACOUSTICAL PATENTS
Authors: Fulop Sean A.
Published: October 2021

The purpose of these acoustical patent reviews is to provide enough information for a Journal reader to decide whether to seek more information from the patent itself. Any opinions expressed here are those of the reviewers as individuals and are not legal opinions. Patents are available via the internet at the USPTO website.
The Tumor Necrosis Factor Alpha and Interleukin 6 Auto-paracrine Signaling Loop Controls Mycobacterium avium Infection via Induction of IRF1/IRG1 in Human Primary Macrophages
Authors: Gidon Alexandre , Louet Claire , Røst Lisa Marie , Bruheim Per , Flo Trude Helen
Published: October 2021

The prevalence of lung diseases caused by nontuberculous mycobacteria, such as
Mycobacterium avium
, is increasing in countries where tuberculosis is not endemic, most likely because of an aging population that is immunocompromised from underlying disease or immunosuppressive therapy. Our study contributes to the understanding of mycobacterial survival and killing in human macrophages and, more broadly, to the impact of immunometabolism during infection.
Does prevention pay off? Economic aspects of sports injury prevention: a systematic review
Authors: Lutter Christoph , Jacquet Christophe , Verhagen Evert , Seil Romain , Tischer Thomas
Published: October 2021

Objective

To identify, summarise and critically assess economic evaluation studies on sports injury prevention strategies.

Design

Systematic review.

Data sources

PubMed, SportDiscuss.

Eligibility criteria for selecting studies

The current literature was searched following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Economic analyses published since 2010 were checked for inclusion. The methodological quality of the studies was assessed using the Oxford Level of Evidence for economic and decision analysis; underlying randomised controlled trials (RCTs) were rated according to the Physiotherapy Evidence Database (PEDro) Scale, and risk of bias was assessed using the Revised Cochrane risk-of-bias tool.

Results

Ten studies fulfilled the inclusion criteria. The quality assessment revealed limited data quality. For trial-based analysis, underlying RCTs were of good quality and had a low risk of bias. Prevention concepts for general injury reduction showed effectiveness and cost savings. Regarding specific injury types, the analysis of the studies showed that the best data are available for ankle, hamstring and anterior cruciate ligament injuries. Measures using specific training interventions were the predominant form of prevention concepts; studies investigating these concepts showed cost-effectiveness with total cost savings between €24.82 and €462 per athlete.

Conclusion

Injury prevention strategies that were studied are cost-effective. However, estimates and outcomes vary throughout the included studies, and precluded pooling of existing data. Knowledge about the cost-effectiveness of evaluated prevention measures will help improve the acceptance and application of prevention initiatives.
Engaging with the private healthcare sector for the control of tuberculosis in India: cost and cost-effectiveness
Authors: Arinaminpathy Nimalan , Nandi Arindam , Vijayan Shibu , Jha Nita , Nair Sreenivas A , Kumta Sameer , Dewan Puneet , Rade Kiran , Vadera Bhavin , Rao Raghuram , Sachdeva Kuldeep S
Published: October 2021

Background

The control of tuberculosis (TB) in India is complicated by the presence of a large, disorganised private sector where most patients first seek care. Following pilots in Mumbai and Patna (two major cities in India), an initiative known as the ‘Public–Private Interface Agency’ (PPIA) is now being expanded across the country. We aimed to estimate the cost-effectiveness of scaling up PPIA operations, in line with India’s National Strategic Plan for TB control.

Methods

Focusing on Mumbai and Patna, we collected cost data from implementing organisations in both cities and combined this data with models of TB transmission dynamics. Estimating the cost per disability adjusted life years (DALY) averted between 2014 (the start of PPIA scale-up) and 2025, we assessed cost-effectiveness using two willingness-to-pay approaches: a WHO-CHOICE threshold based on per-capita economic productivity, and a more stringent threshold incorporating opportunity costs in the health system.

Findings

A PPIA scaled up to ultimately reach 50% of privately treated TB patients in Mumbai and Patna would cost, respectively, US$228 (95% uncertainty interval (UI): 159 to 320) per DALY averted and US$564 (95% uncertainty interval (UI): 409 to 775) per DALY averted. In Mumbai, the PPIA would be cost-effective relative to all thresholds considered. In Patna, if focusing on adherence support, rather than on improved diagnosis, the PPIA would be cost-effective relative to all thresholds considered. These differences between sites arise from variations in the burden of drug resistance: among the services of a PPIA, improved diagnosis (including rapid tests with genotypic drug sensitivity testing) has greatest value in settings such as Mumbai, with a high burden of drug-resistant TB.

Conclusions

To accelerate decline in TB incidence, it is critical first to engage effectively with the private sector in India. Mechanisms such as the PPIA offer cost-effective ways of doing so, particularly when tailored to local settings.
Isolated oral clefts and school grades: population-based cohort study from Norway
Authors: Gjerdevik Miriam , Lie Rolv Terje , Haaland Øystein Ariansen , Berg Erik , Feragen Kristin Billaud , Sivertsen Åse
Published: October 2021

Objective

To compare school grades of adolescents in Norway born with isolated cleft with those of their unaffected peers.

Design

Population-based cohort study.

Setting

Norway.

Patients

A total of 347 419 individuals born in Norway between 1986 and 1992, including 523 isolated cleft cases which were identified using data from Norway’s two treatment centres. Individuals were followed from birth through compulsory school.

Main outcome measures

Grade point average (GPA) from middle school graduation (around the age of 16). Specific subject grades were also investigated.

Results

Using a grade scale from 1–6, the observed mean GPA for the reference group was 3.99. Both cleft lip only (CLO) and cleft lip with cleft palate (CLP) had a mean GPA similar to the reference group (adjusted GPA differences from the reference with 95% CIs of 0.06 (−0.04 to 0.16) and −0.08 (−0.19 to 0.03), respectively). Cleft palate only (CPO) had a marginally lower GPA (adjusted GPA difference: −0.18 (−0.28 to −0.08)). These comparisons were consistent across specific subjects. Overall, the evidence suggests a larger difference in GPA between cases and controls in males compared with females. Females with CLO even had a higher estimated GPA than females in the reference group (adjusted GPA difference: 0.19 (0.013 to 0.36)). Grades were similar regardless of laterality of cleft lip (CLO or CLP).

Conclusion

In Norway, individuals born with isolated CLO or CLP did not have lower average school grades when graduating from middle school. Individuals born with isolated CPO had marginally lower grades.
Adolescent time use and mental health: a cross-sectional, compositional analysis in the Millennium Cohort Study
Authors: Atkin Andrew J , Dainty Jack R , Dumuid Dorothea , Kontostoli Elli , Shepstone Lee , Tyler Richard , Noonan Robert , Richardson Cassandra , Fairclough Stuart J
Published: October 2021

Objective

To examine the association of 24-hour time-use compositions with mental health in a large, geographically diverse sample of UK adolescents.

Design

Cross-sectional, secondary data analysis.

Setting

Millennium Cohort Study (sixth survey), a UK-based prospective birth cohort.

Participants

Data were available from 4642 adolescents aged 14 years. Analytical samples for weekday and weekend analyses were n=3485 and n=3468, respectively (45% boys, 85% white ethnicity).

Primary and secondary outcome measures

Primary outcome measures were the Strengths and Difficulties Questionnaire (SDQ, socioemotional behaviour), Mood and Feelings Questionnaire (MFQ, depressive symptoms) and Rosenberg Self-Esteem Scale (RSE, self-esteem). Behavioural exposure data were derived from 24-hour time-use diaries.

Results

On weekdays, participants spent approximately 54% of their time in sleep, 3% in physical activity, 9% in school-related activities, 6% in hobbies, 11% using electronic media and 16% in domestic activities. Predicted differences in SDQ, MFQ and RSE were statistically significant for all models (weekday and weekend) that simulated the addition or removal of 15 min physical activity, with an increase in activity being associated with improved mental health and vice versa. Predicted differences in RSE were also significant for simulated changes in electronic media use; an increase in electronic media use was associated with reduced self-esteem.

Conclusion

Small but consistent associations were observed between physical activity, electronic media use and selected markers of mental health. Findings support the delivery of physical activity interventions to promote mental health during adolescence, without the need to specifically target or protect time spent in other activities.
Spirometry parameters used to define small airways obstruction in population-based studies: systematic review protocol
Authors: Knox-Brown Ben , Mulhern Octavia , Amaral Andre F S
Published: October 2021

Introduction

In recent years, there has been increasing interest in the use of spirometry for the assessment of small airways obstruction (SAO) driven by the idea that these changes occur prior to development of established obstructive lung disease. Maximal mid-expiratory and distal flow rates have been widely used despite a lack of agreement regarding parameter selection or definition of an abnormal result. We aim to provide evidence from population-based studies, describing the different parameters, definitions of normal range and the resulting impact on prevalence estimates for SAO. Summarising this evidence is important to inform development of future studies in this area.

Methods and analysis

A systematic review of population-based studies will be conducted. MEDLINE, Web of Science and Google Scholar will be searched from database inception to May 2021. Primary outcomes will include the spirometry parameter used to define SAO, and the definition of an abnormal result. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines will be followed for study selection. Study methods will be assessed using the Newcastle-Ottawa scale and the Grading of Recommendations Assessment, Development and Evaluation working group methodology. Narrative synthesis will be conducted for all included studies. Meta-analysis will also be conducted for prevalence estimates and associated risk factors where data quality and availability allow. Random effects models will be used to conduct the meta-analysis and I2statistics will be used to assess heterogeneity across studies. Where appropriate subgroup analysis will be conducted to explore heterogeneity.

Ethics and dissemination

There is no requirement for ethical approval for this project. Findings will be disseminated via peer-reviewed publications and other formats, for example, conferences, congresses or symposia.

PROSPERO registration number

CRD42021250206.
Assessing feasibility of establishing antimicrobial stewardship programmes in two provincial-level hospitals in Vietnam: an implementation research study
Authors: Huong Vu Thi Lan , Ngan Ta Thi Dieu , Thao Huynh Phuong , Quang Le Minh , Hanh Tran Thi Thu , Hien Nguyen Thi , Duc Tran , Vinh Vu Hai , Duc Chau Minh , Dung Em Vo Thi Hoang , Bay Phan Van Be , Oanh Nguyen Thi Thuy , Hang Pham Thi Thuy , Tu Nguyen Thi Cam , Quan Truong Anh , Kesteman Thomas , Dodds Ashley Elizabeth , Anderson Deverick , van Doorn H Rogier
Published: October 2021

Objectives

To investigate the feasibility of establishing hospital-based antimicrobial stewardship (AMS) programmes comprising action-planning, educational interventions and data feedback in two provincial-level hospitals in Viet Nam.

Design and setting

This was an implementation research using participatory action process and existing resources from the Duke Antimicrobial Stewardship Outreach Network with local adjustments. A national stakeholder meeting and Strengths-Weaknesses-Opportunities-Threats (SWOT) analysis were conducted to identify gaps and potential interventions.

Participants

Hospital AMS staff implemented activities throughout the study phases. Routinely collected patient data were analysed to support planning, implementation and evaluation.

Interventions

Hospitals were considered as a complex adaptive system and leveraged their unique characteristics and interconnections to develop 1-year plans containing core interventions (data use, educational training, prospective audit with feedback (PAF) and evaluations).

Outcome measures

We assessed feasibility using outputs from stakeholder meeting, SWOT analysis, baseline data, planning process and implementation.

Results

The stakeholder meeting identified three gaps for AMS at national level: supportive policies, AMS training and core competencies and collaboration. At the hospitals, AMS programmes took 1 year for planning due to lack of hospital-specific procedures and relevant staff competencies. Baseline data (January–December 2019) showed variations in antibiotic consumption: 951 days of therapy (DOT) per 1000 days present in the control and 496 in the intervention wards in hospital 1, and 737 and 714 in hospital 2, respectively. During 1-year implementation, clinical pharmacists audited 1890 antibiotic prescriptions in hospital 1 (June 2020–May 2021) and 1628 in hospital 2 (July 2020–July 2021), and will continue PAF in their daily work.

Conclusion

Our data confirmed the need to contextualise AMS programmes in low-income and middle-income countries (LMICs) and demonstrated the usefulness of implementation research design in assessing programme feasibility. Developing staff competencies, using local data to stimulate actions and integrating programme activities in routine hospital work are key to success in LMICs.
Cost-effectiveness of a quality improvement project, including simulation-based training, on reducing door-to-needle times in stroke thrombolysis
Authors: Ajmi Soffien Chadli , Kurz Martin W , Ersdal Hege , Lindner Thomas , Goyal Mayank , Issenberg S Barry , Vossius Corinna
Published: October 2021

Background

Rapid revascularisation in acute ischaemic stroke is crucial to reduce its total burden including societal costs. A quality improvement (QI) project that included streamlining the stroke care pathway and simulation-based training was followed by a significant reduction in median door-to-needle time (27 to 13 min) and improved patient outcomes after stroke thrombolysis at our centre. Here, we present a retrospective cost-effectiveness analysis of the QI project.

Methods

Costs for implementing and sustaining QI were assessed using recognised frameworks for economic evaluations. Effectiveness was calculated from previously published outcome measures. Cost-effectiveness was presented as incremental cost-effectiveness ratios including costs per minute door-to-needle time reduction per patient, and costs per averted death in the 13-month post-intervention period. We also estimated incremental cost-effectiveness ratios for a projected 5-year post-intervention period and for varying numbers of patients treated with thrombolysis. Furthermore, we performed a sensitivity analysis including and excluding costs of unpaid time.

Results

All costs including fixed costs for implementing the QI project totalled US$44 802, while monthly costs were US$2141. We calculated a mean reduction in door-to-needle time of 13.1 min per patient and 6.36 annual averted deaths. Across different scenarios, the estimated costs per minute reduction in door-to-needle time per patient ranged from US$13 to US$29, and the estimated costs per averted death ranged from US$4679 to US$10 543.

Conclusions

We have shown that a QI project aiming to improve stroke thrombolysis treatment at our centre can be implemented and sustained at a relatively low cost with increasing cost-effectiveness over time. Our work builds on the emerging theory and practice for economic evaluations in QI projects and simulation-based training. The presented cost-effectiveness data might help guide healthcare leaders planning similar interventions.
Bochdalek Hernia in a Soldier
Authors: Connor D. J.
Published: October 2021

Congenital diaphragmatic hernias are most often seen in infants. They may rarely be discovered in adulthood. This case report describes the management of a soldier presenting with acute bowel obstruction and respiratory embarrassment in a military hospital. The surgical repair was achieved with a laparotomy. Effective epidural analgesia and early physiotherapy were axiomatic of his un-complicated post-operative course.
Cutaneous Myiasis with Dermatobia Hominis (Human Bot Fly*) Larvæ Treated both Conservatively and Surgically
Authors: Wild G.
Published: October 2021

A case is presented of infestation with the larvae of Dermatobia hominis (human bot fly). This case is unusual in that it provides an example of three different outcomes for separate lesions in the same patient; spontaneous resolution, conservative treatment and surgical intervention. It also illustrates that myiasis should be included in the differential diagnosis of any skin lesion of a patient returning from the tropics.
Rotating spacetime: black-bounces and quantum deformed black hole
Authors: Xu Zhaoyi , Tang Meirong
Published: October 2021

Recently, two kinds of deformed schwarzschild spacetime have been proposed, which are the black-bounces metric (Simpson and Visser in J Cosmol Astropart Phys 2019:042, 2019, Lobo et al. in Phys Rev D 103:084052, 2021) and quantum deformed black hole (BH) (Berry et al. in arXiv:2102.02471, 2021). In present work, we investigate the rotating spacetime of these deformed Schwarzschild metric. They are exact solutions to the Einstein’s field equation. We analyzed the properties of these rotating spacetimes, such as event horizon (EH), stationary limit surface (SIS), structure of singularity ring, energy condition (EC), etc., and found that these rotating spacetime have some novel properties.
Cross-kink wave, solitary, dark, and periodic wave solutions by bilinear and He’s variational direct methods for the KP–BBM equation
Authors: Feng Baolin , Manafian Jalil , Ilhan Onur Alp , Rao Amitha Manmohan , Agadi Anand H.
Published: October 2021

This paper deals with cross-kink waves in the (2+1)-dimensional KP–BBM equation in the incompressible fluid. Based on Hirota’s bilinear technique, cross-kink solutions related to KP–BBM equation are constructed. Taking the special reduction, the exact expression of different types of solutions comprising exponential, trigonometric and hyperbolic functions is obtained. Moreover, He’s variational direct method (HVDM) based on the variational theory and Ritz-like method is employed to construct the abundant traveling wave solutions of the (2+1)-dimensional generalized Hirota–Satsuma–Ito equation. These traveling wave solutions include kinky dark solitary wave solution, dark solitary wave solution, bright solitary wave solution, periodic wave solution and so on, which are all depending on the initial hypothesis for the Ritz-like method. In continuation, the modulation instability is engaged to discuss the stability of the obtained solutions. Moreover, the rational [Formula: see text] method on the generalized Hirota–Satsuma–Ito equation is investigated. The applicability and effectiveness of the acquired solutions are presented through the numerical results in the form of 3D and 2D graphs. A variety of interactions are illustrated analytically and graphically. The influence of parameters on propagation is analyzed and summarized. The results and phenomena obtained in this paper enrich the dynamic behavior of the evolution of nonlinear waves.
MICROWAVE SYNTHESIS, CHARACTERIZATION AND PROPERTIES EVALUATION OF GEMINI IMIDAZOLINE SURFACTANTS BASED ON DIBROMOPROPANE
Authors: TRIPATHY DIVYA BAJPAI , KUMARI MAYURI
Published: October 2021

Microwave synthesis of imidazolines has been proven to have various advantages over conventional thermal methods in terms of reaction duration, better yield and sustainability. Multi-exploitability of imidazolines at industrial level is globally known. Moreover, claims of multi-fold improvement of the properties of gemini surfactants over their conventional monomeric counterparts challenge the researchers to synthesize gemini imidazoline surfactants using green synthetic routes. Cost-effective products provide an additional demand to commercialize the product easily. This research involves the microwave synthesis of gemini imidazolines using easily available, low-cost reactants. Synthesized products were characterized using standard characterization procedures and were evaluated for their surface-active properties and applications.