bluuebunny/crossref_metadata_2025 huggingface dataset:
An Experimental Study of Sister Holes Film Cooling With Various Secondary-to-Primary Hole Diameter Ratios
Authors: Zhu Rui , Lin Enci , Simon Terrence , Xie Gongnan
Published: October 2020

For increased specific thrust and efficiency, more effective film-cooling schemes are developed with each successive gas turbine design. Adding secondary film-cooling holes to each primary film-cooling hole represents such improvement without significantly increasing cost. Presented is an experimental investigation on the effects of secondary-to-primary hole diameter ratio on film-cooling performance and flow structure in the coolant-to-passage flow merge zone. Film-cooling effectiveness values and heat transfer coefficients are measured in the vicinity of the hole by the thermochromic liquid crystal (TLC) technique. Measured in-flow temperature fields in the coolant emerging zone identify flow makeup, whether coolant or passage. Furthermore, complementary flow and thermal fields are numerically documented. The Reynolds number based on mainstream velocity and primary hole diameter is 20,300, a representative value. Performance features are compared at three blowing ratios (0.5, 1.0, and 1.5) and two mass flow ratios (3.43% and 5.15%). Secondary holes improve film-cooling effectiveness, especially when blowing rate is high. Secondary holes create an “antikidney vortex structure” that weakens the main kidney vortex pair which helps keep coolant attached to the surface, allowing more effective laterally spreading. However, adding secondary holes increases heat transfer coefficients, especially at high blowing rates. The secondary-to-primary hole diameter ratio is an important parameter. Larger secondary holes can counteract the detrimental effects of having higher blowing ratios, but with increased blowing ratios this improvement subsides. An optimum diameter ratio is sought.
Cost-Effective Additive Manufacturing of Ambient Pressure-Dried Silica Aerogel
Authors: Guo Zipeng , Yang Ruizhe , Wang Tianjiao , An Lu , Ren Shenqiang , Zhou Chi
Published: October 2020

The conventional manufacturing processes for aerogel insulation materials mostly rely on the supercritical drying, which suffers from issues of massive energy consumption, high-cost equipment, and prolonged processing time. Considering the large market demand for the aerogel insulation material in the next decade, a cost-effective and scalable fabrication technique is highly desired. In this paper, a direct ink writing (DIW) method is used to three-dimensionally fabricate the silica aerogel insulation material, followed by room-temperature and ambient pressure drying. Compared with the supercritical drying and freeze-drying techniques, the reported method significantly reduces the fabrication time and costs. The cost-effective DIW technique offers the capability to print complex hollow internal structures, coupled with the porous aerogel structure, it is found to be beneficial for the thermal insulation property. The addition of fiber to the ink assures the durability of the fabricated product, without sacrificing the thermal insulation performance. The foam ink preparation methods and the printability are demonstrated in this paper, along with the printing of complex three-dimensional geometries. The thermal insulation performance of the printed objects is characterized, and the mechanical properties were also examined. The proposed approach is found to have a 56% reduction in the processing time. The printed silica aerogels exhibit a low thermal conductivity of 0.053 W m−1 K−1.
Modeling Large Spatial Deflections of Slender Beams of Rectangular Cross Sections in Compliant Mechanisms
Authors: Bai Ruiyu , Chen Guimin
Published: October 2020

Modeling large spatial deflections of flexible beams has been one of the most challenging problems in the research of compliant mechanism. This study presents an approach called chained power series model for modeling large spatial defections of flexible beams with uniform rectangular cross section. This approach is based on the power series model developed in our previous work for modeling spatial deflections of rectangular beams in the intermediate deflection range. The chained power series model splits a rectangular beam into several elements and models each element by the power series model, and then, the deflections of all elements are assembled to form the deflection of the beam through transformations using quaternions. The effectiveness of the approach is demonstrated by comparing with the nonlinear finite element model preformed in ansys and the chained 3D pseudo-rigid-body model. Several examples are demonstrated to show the capability of the chained power series model for solving the deflections of rectangular beams in compliant mechanisms.
Design and Kinematic Analysis of a Flexible-Link Parallel Mechanism With a Spatially Quasi-Translational End Effector
Authors: Pan Hao , Chen Genliang , Kang Yezheng , Wang Hao
Published: October 2020

Intrinsic passive compliance of flexible-link parallel mechanisms makes them suitable for situations where compliant manipulation is necessary. In this work, through using elastic rods as limbs, a flexible-link parallel mechanism whose end effector can move translationally with a large workspace is proposed. The middle plate and end effector are connected to the base via two groups of three elastic rods, which are arranged in a cylindrically symmetric way with a phase difference of 60 deg. Concurrently, the middle plate is coupled with the elastic rods connected to the end effector via sliding connection. Besides, a rotating set of coplanar wheels is introduced to provide smooth coupling for the prototype. Three actuation modules are used to drive the end effector, while another three to compensate toward its configuration deviations caused by deformation compatibility. Then, based on principal axes decomposition of compliance matrix, kinetostatics models for inverse and forward kinematics are established. The numerical analysis reveals that the end effector can make quasi 3-degrees-of-freedom (DOF) translation in a large space with extremely small twist. Finally, workspace experiments at four typical slices and pose accuracy evaluation along continuous trajectories are carried out, and the results demonstrate that our design and theoretical model are correct.
WearGP: A UQ/ML Wear Prediction Framework for Slurry Pump Impellers and Casings
Authors: Tran Anh , Wang Yan , Furlan John , Pagalthivarthi Krishnan V. , Garman Mohamed , Cutright Aaron , Visintainer Robert
Published: October 2020

Dedicated to the memory of John Furlan.

Wear prediction is important in designing reliable machinery for slurry industry. It usually relies on multi-phase computational fluid dynamics, which is accurate but computationally expensive. Each run of the simulations can take hours or days even on a high-performance computing platform. The high computational cost prohibits a large number of simulations in the process of design optimization. In contrast to physics-based simulations, data-driven approaches such as machine learning are capable of providing accurate wear predictions at a small fraction of computational costs, if the models are trained properly. In this paper, a recently developed WearGP framework [1] is extended to predict the global wear quantities of interest by constructing Gaussian process surrogates. The effects of different operating conditions are investigated. The advantages of the WearGP framework are demonstrated by its high accuracy and low computational cost in predicting wear rates.
Optimization of NACA 0012 Airfoil Performance in Dynamics Stall Using Continuous Suction Jet
Authors: Tadjfar M. , Kasmaiee Siroos , Noori S.
Published: October 2020

Many different active flow control methods are used to manipulate the flow field about aerodynamic surfaces in order to obtain the most desirable aerodynamic performance. Among these techniques, boundary layer suction is one of the most effective techniques used to improve aerodynamic performance of the airfoil. In this study, the configuration of a pure suction jet actuator is optimized over an oscillating NACA0012 airfoil at the Reynolds number of 1.35 × 105 to control the dynamic stall behavior. The airfoil was pitched around the quarter-chord location with a sinusoidal motion and the angle of attack was varied between −5 and 25 degrees. Genetic algorithm was implemented as the optimization method. However, since large number of numerical simulations were required for this purpose, an artificial neural network was employed for training a function between the control parameters and the airfoil aerodynamic coefficients. Aerodynamic performance defined as lift-to-drag ratio was chosen as the objective function of the optimization. Location, velocity amplitude, opening length and jet incidence angle were the control parameters of this optimization.

It was shown that when the velocity amplitude and opening length were maximum, the airfoil reached its highest performance. Moreover, the aerodynamic characteristics of the airfoil were remarkably improved when the jet incident angle approached to 90 degrees. Placing the suction jet actuator in the range between 3 to 6 percent of the airfoil chord, was found to have the greatest effect on improving the aerodynamic performance. For the optimum configuration, the airfoil separation. It was shown that when the velocity amplitude and opening length were maximum, the airfoil reached its highest performance. Moreover, the aerodynamic characteristics of the airfoil were peaked in the range between 90 to 120 degrees, with 107 having the best performance in our database.
Heat Transfer Prediction With Unknown Thermal Boundary Conditions Using Physics-Informed Neural Networks
Authors: Cai Shengze , Wang Zhicheng , Chryssostomidis Chryssostomos , Karniadakis George Em
Published: October 2020

Simulating convective heat transfer using traditional numerical methods requires explicit definition of thermal boundary conditions on all boundaries of the domain, which is almost impossible to fulfill in real applications. Here, we address this ill-posed problem using machine learning techniques by assuming that we have some extra measurements of the temperature at a few locations in the domain, not necessarily located on the boundaries with the unknown thermal boundary condition. In particular, we employ physics-informed neural networks (PINNs) to represent the velocity and temperature fields while simultaneously enforce the Navier-Stokes and energy equations at random points in the domain. In PINNs, all differential operators are computed using automatic differentiation, hence avoiding discretization in either space or time. The loss function is composed of multiple terms, including the mismatch in the velocity and temperature data, the boundary and initial conditions, as well as the residuals of the Navier-Stokes and energy equations. Here, we develop a data-driven strategy based on PINNs to infer the temperature field in the prototypical problem of convective heat transfer in flow past a cylinder. We assume that we have just a couple of temperature measurements on the cylinder surface and a couple more temperature measurements in the wake region, but the thermal boundary condition on the cylinder surface is totally unknown. Upon training the PINN, we can discover the unknown boundary condition while simultaneously infer the temperature field everywhere in the domain with less than 5% error in the Nusselt number prediction. In order to assess the performance of PINN, we carried out a high fidelity simulation of the same heat transfer problem (with known thermal boundary conditions) by using the high-order spectral/hp-element method (SEM), and quantitatively evaluated the accuracy of PINN’s prediction with respect to SEM. We also propose a method to adaptively select the location of sensors in order to minimize the number of required temperature measurements while increasing the accuracy of the inference in heat transfer.
Pipe-Size Scale-Up of Frictional Head Loss in Settling Slurry Flows Using Predictive Models: Experimental Validation
Authors: Matoušek Václav , Visintainer Robert , Furlan John , Sellgren Anders
Published: October 2020

Transported Newtonian settling slurries (mixtures of solid particles and carrying liquid) tend to stratify in a slurry pipeline and the degree of their stratification significantly affects the frictional head loss in a pipeline system. Solid particles can span a broad range of sizes from those typical for fine sand to those typical for coarse gravel. Different fractions of solids have different properties and form different flow patterns. The different patterns are associated with different dominating particle support mechanisms and friction mechanisms in slurry flow. Hence, there are different models describing and predicting the frictional head loss in pipe flows of different settling slurries. In the presented work, we focus on friction-loss models for heterogeneous (partially-stratified) flow (V50-model), and for fully-stratified flow (Vsm-model). The models can serve as tools to scale up information on frictional head loss in flow of specific slurry obtained experimentally in a small laboratory pipe to larger pipes of industrial sizes. So far, the reliability of the scale up has been difficult to verify as an availability of coarse particle experimental data was restricted to small laboratory pipes (an internal diameter of a pipe typically not larger than 100 mm) and data from larger pipes were extremely scarce.

In 2016 and 2019, extensive experimental campaigns were conducted in the GIW Hydraulic Laboratory (Grovetown, GA, U.S.A.) testing flows of Newtonian settling slurries in pipes of 3 very different sizes (103 mm, 203 mm, and 489 mm). We exploit the experimental data to evaluate the pipe-size scale-up ability of the heterogeneous V50-model and the stratified Vsm-model. The evaluation includes an analysis of the pipe-size effect on the characteristic velocities of the models: the suspension velocity V50 and the deposition-limit velocity Vsm.
An Experimental Investigation on the Erosion of a Helico-Axial Pump With Gas Presence
Authors: Chen Yi , Patil Abhay , Chen Yiming , Morrison Gerald , Rojas Marisela
Published: October 2020

Electrical submersible pump (ESP) technology has been widely applied in the oil and gas industry due to its high productivity. However, erosion always causes the reduction of productivity and sometimes even the failure of an ESP system. This study explores the effect of gas presence on erosion mechanism on an ESP which is composed of 4 stages of Helico-Axial Pump (HAP). A 200-hour erosion test has been performed on this ESP. During the test, the ESP was running at 3600 RPM with a liquid flow rate of 880 GPM, 20% inlet Gas Volume Fraction (GVF), and 0.24% sand concentration by weight. Performance tests were conducted every 50 hours to acquire the performance maps and monitor the performance degradation. Analysis of volume/weight loss and performance degradation is conducted to investigate pump wear. Two types of erosion are found at the impeller: the volume loss found notably at the leading edge is mainly caused by two-body impact erosion, while the tip clearance increment between the impeller housing and impeller blade tip is mainly caused by the three-body abrasive erosion. Unlike most conventional centrifugal pumps, there is no observable wear found at the trailing edge of the impeller. The presence of the gas shows a negative effect on both types of erosion. The consequence of the erosion is the performance degradation, especially at the condition with higher pressure rise. It is suggested to apply this HAP in the oil field with more gas and higher bottom hole pressure.
DNA Ligation on a Digital Microfluidic Device
Authors: An H. T. , Houchaimi S. , Greyson Marcette , Schertzer M. J.
Published: October 2020

This investigation demonstrates that digital microfluidic platforms are suitable for automated DNA ligation. Multiple DNA ligation steps are required to create DNA products using oligonucleotide synthesis. Unfortunately, traditional methods of oligonucleotide synthesis are unable to create highly accurate, long DNA products. This leads to a supply-side bottleneck that puts a drag on innovation in drug development, organism engineering, and agricultural improvement. Here we demonstrate ligation of two DNA products into one DNA product in digital microfluidic devices that manipulate droplets in air and in oil. Results from the gel electrophoresis imaging confirmed that ligation on digital microfluidics devices was successful in all cases. Silicone oil experiments also verified that on-chip incubation of DNA ligation is possible on these devices using an external resistive heater. This suggests that large-scale DMF automation of DNA synthesis can be used to alleviate the bottleneck created by the lack of efficient, high-volume production of long change DNA products. Such an advancement would be highly valued for a wide variety of biomedical applications.
Temperature-Controlled Minichannel Flow-Cell for Non-Invasive Particle Measurements in Solid-Liquid Flow
Authors: Schmalenberg Mira , Sallamon Fabian , Haas Christian , Kockmann Norbert
Published: October 2020

Solid-liquid suspension flow is often involved in the production of pharmaceuticals and fine chemicals. In these fields, working with continuous small-scale equipment in order to save costs and resources is of increasing interest. Therefore, it is also important to enable process control for small-scale apparatus, which requires the development of new concepts to observe and control crystallization processes in minichannel equipment. The particles and crystals should be detected and measured with as low impact as possible because contact between process medium and the sensors can often lead to the incrustation of the sensor, disturb the particle size and shape, or contaminate the system.

For the observation of crystallizing processes in minichannel crystallizers, a non-invasive, temperature-controlled flow-cell is designed in this work. In particular, this flow cell has been designed to examine crystals in a fluorinated ethylene propylene (FEP) tube with an inner diameter of 1.6 mm. Crystals can be investigated using a standard optical camera and microscope. An image processing routine enables the evaluation of crystal size. This is crucial for the assessment of the process and crystal size distribution, which is often a quality criterion in the crystallization process.

The contribution will show how the flow-cell for two-phase flow is constructed and the evaluation routine is implemented. Based on experimental data, the applicability of the equipment and the evaluation method are described.
Mapping coastal circulations using moving vehicle acoustic tomography
Authors: Chen KuanYu , Huang Chen-Fen , Huang Sheng-Wei , Liu Jin-Yuan , Guo Jenhwa
Published: October 2020

With the increased availability of highly maneuverable unmanned surface/underwater vehicles, abundant ocean data can now be collected. This study uses tomographic techniques to extend the survey area covered by moving vehicles. An acoustic reciprocal transmission experiment was conducted using three tomographic sensors installed on an autonomous underwater vehicle, a fishing ship, and a buoy. The distributed sensing method is applied for currents estimation. The estimated currents near the ship show consistent results with the direct measurements. In particular, an anticyclonic circulation was revealed. Further, a general least-squares method is employed to improve the estimate of this vortical structure.
Acoustic source localization with the angular spectrum approach in continuously stratified media
Authors: Schoen Scott , Arvanitis Costas D
Published: October 2020

The angular spectrum approach (ASA)—a frequency domain method to calculate the acoustic field—enables highly efficient passive source localization and modeling forward propagation in homogeneous media. If the medium is continuously stratified, a first-order analytical solution may be obtained for the field at arbitrary depth. Simulations show that the proposed stratified ASA solution enables accurate source localization as compared to the uncorrected ASA (error from 1.2 ± 0.3 to 0.49 ± 0.3 wavelengths) at scalings relevant to biomedical, underwater, and atmospheric acoustic applications, and requiring milliseconds on nonspecialized hardware. The results suggest the proposed correction enables efficient and accurate localization in stratified environments.
On the tympanic membrane impedance of the katydid Copiphora gorgonensis (Insecta: Orthoptera: Tettigoniidae)
Authors: Celiker Emine , Jonsson Thorin , Montealegre-Z Fernando
Published: October 2020

Katydids (bush-crickets) are endowed with tympanal ears located in their forelegs' tibiae. The tympana are backed by an air-filled tube, the acoustic trachea, which transfers the sound stimulus from a spiracular opening on the thorax to the internal side of the tympanic membranes (TM). In katydids the sound stimulus reaches both the external and internal side of the membranes, and the tympanal vibrations are then transferred to the hearing organ crista acustica (CA) that contains the fluid-immersed mechanoreceptors. Hence the tympana are principally involved in transmitting and converting airborne sound into fluid vibrations that stimulate the auditory sensilla. Consequently, what is the transmission power to the CA? Are the TM tuned to a certain frequency? To investigate this, the surface normal acoustic impedance of the TM is calculated using finite-element analysis in the katydid Copiphora gorgonensis. From this, the reflectance and transmittance are obtained at the TM. Based on the impedance results obtained from the pressure recordings at TM and the velocity field calculations in the AT, in the frequency range 5–40 kHz, it is concluded that the tympana have considerably higher transmission around 23 kHz, corresponding to the dominant frequency of the male pure-tone calling song in this species.
Fast and Robust Algorithm for Detecting Body Posture Using Wrist-Worn Accelerometers
Authors: Straczkiewicz Marcin , Glynn Nancy W. , Zipunnikov Vadim , Harezlak Jaroslaw
Published: October 2020

Background: The increasing popularity of wrist-worn accelerometers introduces novel challenges to the research on physical activity and sedentary behavior. Estimation of body posture is one such challenge. Methods: The authors proposed an approach called SedUp to differentiate between sedentary (sitting/lying) and standing postures. SedUp is based on the logistic regression classifier, using the wrist elevation and the motion variability extracted from raw accelerometry data collected on the axis parallel to the forearm. The authors developed and tested our method on data from N = 45 community-dwelling older adults. All subjects wore ActiGraph GT3X+ accelerometers on the left and right wrist, and activPAL was placed on the thigh in the free-living environment for 7 days. ActivPAL provided ground truth about body posture. The authors reported SedUp’s classification accuracy for each wrist separately. Results: Using the data from the left wrist, SedUp estimated the standing posture with median true positive rate = 0.83 and median true negative rate = 0.91. Using the data from the right wrist, SedUp estimated the standing posture with median true positive rate = 0.86 and median true negative rate = 0.93. Conclusions: SedUp provides accurate classification of body posture using wrist-worn accelerometers. The separate validation for each wrist allows for the application of SedUp in a wide spectrum of free-living studies.
Higher-Order Interactions Dampen Pairwise Competition in the Zebrafish Gut Microbiome
Authors: Sundarraman Deepika , Hay Edouard A. , Martins Dylan M. , Shields Drew S. , Pettinari Noah L. , Parthasarathy Raghuveer
Published: October 2020

Understanding the rules governing the composition of the diverse microbial communities that reside in the vertebrate gut environment will enhance our ability to manipulate such communities for therapeutic ends. Synthetic microbial communities, assembled from specific combinations of microbial species in germfree animals, allow investigation of the fundamental question of whether multispecies community composition can be predicted solely based on the combined effects of interactions between pairs of species. If so, such predictability would enable the construction of communities with desired species from the bottom up. If not, the apparent higher-order interactions imply that emergent community-level characteristics are crucial. Our findings using up to five coexisting native bacterial species in larval zebrafish, a model vertebrate, provide experimental evidence for higher-order interactions and, moreover, show that these interactions promote the coexistence of microbial species in the gut.
Inside the volcano: Three-dimensional magmatic architecture of a buried shield volcano
Authors: Walker Faye , Schofield Nick , Millett John , Jolley Dave , Holford Simon , Planke Sverre , Jerram Dougal A. , Myklebust Reidun
Published: October 2020

The nature and growth of magmatic plumbing systems are of fundamental importance to igneous geology. Traditionally, magma chambers have been viewed as rapidly emplaced bodies of molten rock or partially crystallized “magma mush” connected to the surface by a narrow cylindrical conduit (referred to as the “balloon-and-straw” model). Recent data suggest, however, that magma chambers beneath volcanoes are formed incrementally through amalgamation of smaller intrusions. Here we present the first high-resolution three-dimensional reconstruction of an ancient volcanic plumbing system as a large laccolithic complex. By integrating seismic reflection and gravity data, we show that the ∼200 km3 laccolith appears to have formed through partial amalgamation of smaller intrusions. The complex appears to have fed both surface volcanism and an extensive sill network beneath the volcanic edifice. Numerous sills are imaged within the volcanic conduit, indicating that magma stalled at various levels during its ascent. Our results reveal for the first time the entire multicomponent plumbing system within a large ancient shield volcano.
Supplemental Material: Hooked on salt: Rethinking Alpine tectonics in Hallstatt (Eastern Alps, Austria)
Authors: Fernández Oscar , al. et
Published: October 2020

Digital outcrop model of the Echernwand and description of the methodologies used for digital outcrop construction and for cross-section construction and restoration.
Changing trends of HIV, syphilis, HCV infections and behavioural factors among female sex workers in Chongqing, China: findings from six serial surveillance surveys
Authors: Hu Ling , Wu Guohui , Lu Rongrong , Zhu Hua , Qiu Hongfang , Jing Dan , Ye Mengliang
Published: October 2020

Objectives

To explore the prevalence and changing trends of HIV, syphilis, hepatitis C virus (HCV) infections and risk behaviours among female sex workers (FSWs) and to provide reference and theoretical basis for formulating targeted interventions.

Design

Six consecutive cross-sectional surveys.

Setting

Chongqing, China.

Participants

FSWs were included if they (1) were aged ≥16 years, (2) provided commercial sex for money or goods during the previous month and (3) were willing to participate in the survey and could provide verbal informed consent. This study included 16 791 of 16 810 participants recruited between 2013 and 2018.

Primary and secondary outcome measures

The prevalence of HIV/syphilis/HCV infection.

Results

The HIV and HCV prevalence among FSWs in Chongqing was stable during the study period, but the prevalence of syphilis had an increasing trend, particularly among low-tier and middle-tier FSWs. Improvements in HIV-related knowledge, condom use, injecting drug use and participation in HIV-related services were observed. However, no change was found in the prevalence of drug use. HIV infection was correlated with no condom use in the last commercial sex (adjusted OR (aOR) 3.48, 95% CI 1.90 to 6.37) and syphilis infection (aOR 4.88, 95% CI 1.95 to 12.18). Syphilis infection was correlated with inconsistent condom use (aOR 1.30, 95% CI 1.02 to 1.65), HIV infection (aOR 5.88, 95% CI 2.40 to 14.41), HCV infection (aOR 7.68, 95% CI 4.37 to 13.49) and sexually transmitted infection (STI) diagnosis in the past year (aOR 3.81, 95% CI 2.40 to 6.03). HCV infection was associated with injecting drug use (aOR 8.91, 95% CI 4.45 to 17.86) and syphilis infection (aOR 7.88, 95% CI 4.49 to 13.83).

Conclusions

Comprehensive interventions targeting FSWs, particularly low-tier and middle-tier FSWs, should be increasingly implemented to prevent and control HIV, syphilis and other STIs.
Impact of health insurance on healthcare utilisation patterns in Vietnam: a survey-based analysis with propensity score matching method
Authors: Thuong Nguyen Thi Thu
Published: October 2020

Objectives

The study aims to evaluate the impact of the Revised Health Insurance Law 2014 on the utilisation of outpatient and inpatient care services, healthcare services utilisation at different levels of providers, types of providers and types of visits across different entitlement groups.

Design/setting

Secondary data from two waves of the Vietnam Household Living Standard Survey (VHLSS) 2016, VHLSS 2014 were used. A cross-sectional study applying propensity score matching was conducted.

Participants

A total of 4900 individuals who reported using healthcare services are analysed.

Outcomes measure

Numbers of outpatient and inpatient visits, frequency of healthcare service utilisation at commune health stations, district hospitals, provincial hospitals, public and private health facilities, number of visits at health facility for medical treatment and health checks per year.

Results

The result indicates that health insurance (HI) policy increased the number of outpatient visits for the enrolled between 0.87 and 1.29. The greatest impact was found on participants of heavily subsidised health insurance (HSHI) programmes with 1.29 visits per person per year. Similarly, an increase between 0.08 and 0.16 in the number of inpatient admissions was because of participation in HI. With regard to type of healthcare providers, the study found that participation in HI has the most effect on the use of healthcare services at district hospitals. However, the study demonstrated that the impacts of HI on the increase in the frequency of visiting commune health stations, number of visits at the provincial hospital for HSHI groups, and number of visits at health facilities for health check and consultation were sensitive to unobserved characteristics.

Conclusion

Our findings imply that policy-makers in Vietnam could continue expanding health insurance coverage to increase access to healthcare services for citizens, especially vulnerable groups. In addition, the government should draw more attention to primary healthcare level.
Health outcomes of 1000 children born to mothers with inflammatory bowel disease in their first 5 years of life
Authors: Kanis Shannon Linda , Modderman Sanne , Escher Johanna C , Erler Nicole , Beukers Ruud , de Boer Nanne , Bodelier Alexander , Depla Annekatrien C T.M , Dijkstra Gerard , van Dijk Anne-Baue Ruth Margaretha , Gilissen Lennard , Hoentjen Frank , Jansen Jeroen M , Kuyvenhoven Johan , Mahmmod Nofel , Mallant-Hent Rosalie C , van der Meulen-de Jong Andrea E , Noruzi Anahita , Oldenburg Bas , Oostenbrug Liekele E , Ter Borg Pieter C.J. , Pierik Marieke , Romberg- Camps Mariëlle , Thijs Willem , West Rachel , de Lima Alison , van der Woude C Janneke
Published: October 2020

Objective

The aim of this study was to describe the long-term health outcomes of children born to mothers with inflammatory bowel disease (IBD) and to assess the impact of maternal IBD medication use on these outcomes.

Design

We performed a multicentre retrospective study in The Netherlands. Women with IBD who gave birth between 1999 and 2018 were enrolled from 20 participating hospitals. Information regarding disease characteristics, medication use, lifestyle, pregnancy outcomes and long-term health outcomes of children was retrieved from mothers and medical charts. After consent of both parents, outcomes until 5 years were also collected from general practitioners. Our primary aim was to assess infection rate and our secondary aims were to assess adverse reactions to vaccinations, growth, autoimmune diseases and malignancies.

Results

We included 1000 children born to 626 mothers (381 (61%) Crohn’s disease, 225 (36%) ulcerative colitis and 20 (3%) IBD unclassified). In total, 196 (20%) had intrauterine exposure to anti-tumour necrosis factor-α (anti-TNF-α) (60 with concomitant thiopurine) and 240 (24%) were exposed to thiopurine monotherapy. The 564 children (56%) not exposed to anti-TNF-α and/or thiopurine served as control group. There was no association between adverse long-term health outcomes and in utero exposure to IBD treatment. We did find an increased rate of intrahepatic cholestasis of pregnancy (ICP) in case thiopurine was used during the pregnancy without affecting birth outcomes and long-term health outcomes of children. All outcomes correspond with the general age-adjusted population.

Conclusion

In our study, we found no association between in utero exposure to anti-TNF-α and/or thiopurine and the long-term outcomes antibiotic-treated infections, severe infections needing hospital admission, adverse reactions to vaccinations, growth failure, autoimmune diseases and malignancies.
Haplotypes of (−794(CATT)5–8/−173G>C) MIF gene polymorphisms and its soluble levels in basal cell carcinoma in western Mexican population
Authors: Guevara-Gutiérrez Elizabeth , Castro-Jonguitud María José , De la Torre-Flores Susana Elizabeth , Muñoz-Valle José Francisco , Tlacuilo-Parra Alberto , Salazar-Torres Francisco Javier , Valle Yeminia , Padilla-Gutiérrez Jorge Ramón , Martínez-Fernández Diana Emilia , Valdés-Alvarado Emmanuel
Published: October 2020

Basal cell carcinoma (BCC) is the most common dermatological neoplasms in Caucasian populations. In Mexico, a prevalence of 3.9 per 1000 habitants is estimated. Recently, the macrophage migration inhibitory factor (MIF) has been related to different types of cancer. Therefore, this study aimed to investigate the genetic association of haplotypes of [-794(CATT)5-8/-173G>C]MIF gene polymorphisms and its soluble levels in BCC. A total of 360 individuals were recruited for the study, that is, 180 of the total amounts were patients with BCC histologically confirmed and the remaining 180 individuals were identified as control subjects (CS). Both polymorphisms were genotyped by PCR and PCR-RFLP (restriction fragment length polymorphism), and MIF serum levels were measured by ELISA kit. A borderline difference was found between the 55 genotype and the susceptibility to BCC (5.6% vs 1.7% in BCC and CS, respectively, OR=3.7 and p=0.04). Furthermore, the haplotype 7G showed a significant association with BCC (p=0.02, OR=1.99). Concerning MIF soluble levels, patients with BCC showed a media of 2.1 ng/mL and CS showed 4.4 ng/mL, the comparison between groups was significant (p<0.01). Our findings suggest that the 55 genotype and the haplotype 7G are associated with the susceptibility to BCC; furthermore, a significant difference was found between MIF soluble levels in both study groups.
Breast cancer-induced immune suppression in the sentinel lymph node is effectively countered by CpG-B in conjunction with inhibition of the JAK2/STAT3 pathway
Authors: van Pul Kim M , Vuylsteke Ronald J C L M , de Beijer Monique T A , van de Ven Rieneke , van den Tol M Petrousjka , Stockmann Hein B A C , de Gruijl Tanja D
Published: October 2020

Background

We previously showed selectively hampered activation of lymph node-resident (LNR) dendritic cell (DC) subsets in the breast cancer (BrC) sentinel lymph node (SLN) to precede a state of profound T cell anergy. Reactivating these DC subsets by intratumoral delivery of the Toll-like receptor-9 (TLR9) agonist CpG-B could potentially offer a promising immune therapeutic strategy to combat this immune suppression and prevent disease spread. Unfortunately, CpG-B can limit its own immune stimulatory activity through direct TLR9-mediated activation of signal transducer and activator of transcription 3 (STAT3), pinpointed as a key regulator of immune suppression in the tumor microenvironment. Here, we have investigated whether in vitro exposure to CpG-B, with or without simultaneous inhibition of STAT3 signaling, could overcome immune suppression in BrC SLN.

Methods

Immune modulatory effects of CpG-B (CPG7909) with or without the JAK2/STAT3 inhibitor (STAT3i) AG490 were assessed in ex vivo cultured BrC SLN-derived single-cell suspensions (N=29). Multiparameter flow cytometric analyses were conducted for DC and T cell subset characterization and assessment of (intracellular) cytokine profiles. T cell reactivity against the BrC-associated antigen Mammaglobin-A was determined by means of interferon-γ ELISPOT assay.

Results

Although CpG-B alone induced activation of all DC subsets, combined inhibition of the JAK2/STAT3 pathway resulted in superior DC maturation (ie, increased CD83 expression), with most profound activation and maturation of LNR DC subsets. Furthermore, combined CpG-B and JAK2/STAT3 inhibition promoted Th1 skewing by counterbalancing the CpG-induced Th2/regulatory T cell response and significantly enhanced Mammaglobin-A specific T cell reactivity.

Conclusion

Ex vivo immune modulation of the SLN by CpG-B and simultaneous JAK2/STAT3 inhibition can effectively overcome BrC-induced immune suppression by preferential activation of LNR DC, ultimately restoring type 1-mediated antitumor immunity, thereby securing a BrC-specific T cell response. These findings provide a clear rationale for clinical exploration of SLN-immune potentiation through local CpG/STAT3i administration in patients with BrC.
Ethical challenges for women’s healthcare highlighted by the COVID-19 pandemic
Authors: Bruno Bethany , Shalowitz David I , Arora Kavita Shah
Published: October 2020

Healthcare policies developed during the COVID-19 pandemic to safeguard community health have the potential to disadvantage women in three areas. First, protocols for deferral of elective surgery may assign a lower priority to important reproductive outcomes. Second, policies regarding the prevention and treatment of COVID-19 may not capture the complexity of the considerations related to pregnancy. Third, policies formulated to reduce infectious exposure inadvertently may increase disparities in maternal health outcomes and rates of violence towards women. In this commentary, we outline these challenges unique to women’s healthcare in a pandemic, provide preliminary recommendations and identify areas for further exploration and refinement of policy.
Minimally invasive mitral valve surgery: a systematic safety analysis
Authors: Ko Kinsing , de Kroon Thom L , Post Marco C , Kelder Johannes C , Schut Karen F , Saouti Nabil , van Putte Bart P
Published: October 2020

Objective

Minimally invasive surgery is increasingly adopted as an alternative to conventional sternotomy for mitral valve pathology in many centres worldwide. A systematic safety analysis based on a comprehensive list of pre-specified 30-day complications defined by the Mitral Valve Academic Consortium (MVARC) criteria is lacking. The aim of the current study was to systematically analyse the safety of minimally invasive mitral valve surgery in our centre based on the MVARC definitions.

Methods

All consecutive patients undergoing minimally invasive mitral valve surgery through right mini-thoracotomy in our institution within 10 years were studied retrospectively. The primary outcome was a composite of 30-day major complications based on MVARC definitions.

Results

745 patients underwent minimally invasive mitral valve surgery (507 repair, 238 replacement), with a mean age of 62.9±12.3 years. The repair was successful in 95.8%. Overall 30-day mortality was 1.2% and stroke rate 0.3%. Freedom from any 30-day major complications was 87.2%, and independent predictors were left ventricular ejection fraction <50% (OR 1.78; 95% CI 1.02 to 3.02) and estimated glomerular filtration rate <60 mL/min/1.73 m2(OR 1.98; 95% CI 1.17 to 3.26).

Conclusions

Minimally invasive mitral valve surgery is a safe technique and is associated with low 30-day mortality and stroke rate.
Circle of Willis variants are not associated with thrombectomy outcomes
Authors: Seifert-Held Thomas , Eberhard Katharina , Christensen Soren , Hofer Edith , Enzinger Christian , Albers Gregory W , Lansberg Maarten
Published: October 2020

Background

The circle of Willis (COW) is part of the brain collateral system. The absence of COW segments may affect functional outcome in patients with ischaemic stroke undergoing endovascular therapy.

Methods

In 182 patients in the Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution 2 Study and the CT Perfusion to Predict Response to Recanalisation in Ischaemic Stroke Project, COW anatomy was evaluated on postinterventional magnetic resonance angiography. The absence of the posterior communicating artery or the first segments of posterior or anterior cerebral arteries ipsilateral to the ischaemic infarction was rated as an incomplete COW. Logistic regression was applied to evaluate an association with the patients’ modified Rankin scale (mRS) at 90 days after stroke

Results

An incomplete ipsilateral COW was not predictive of the patients’ mRS at 90 days after stroke. Significant associations were shown for the patients’ baseline National Institutes of Health Stroke Scale (NIHSS), age and reperfusion status. The effect size suggests that a significant association of an incomplete COW with the mRS at 90 days may be obtained in cohorts of more than 3000 patients.

Conclusions

Compared with the established predictors NIHSS, age and reperfusion status, an incomplete COW is not associated with functional outcome after endovascular therapy.
Customer–Supplier Relationships and Abnormal Accruals
Authors: Bao May Xiaoyan , Billett Matthew T. , Liu Yixin
Published: October 2020

We investigate the relationship between customer and supplier firms’ abnormal accruals to examine whether the supply chain is an important transmission channel of abnormal accruals. We propose “earnings management” hypothesis and “customer demand shock” hypothesis. Empirically, we examine the relation between a supplier’s estimated abnormal accruals and those of its major customers using Compustat Business Segment Files over the period 1987–2015. To further explore the demand shock channel, we directly test the impact of the bullwhip effect (BWE) on the linkage in abnormal accruals along the supply chain. Following the literature in operation management, we construct the amplification ratio, measured as the coefficient of variation of a firm’s orders divided by the coefficient of variation of the firm’s demand. We find that customer firms’ demand shocks link customer and supplier abnormal accruals as they propagate along the supply chain, via the BWE. Our evidence supports “customer demand shock” hypothesis. Consistent with the view that improving predictions on orders from their customers would mitigate this BWE, we find that a customer’s abnormal accruals have a much smaller impact on those of its suppliers whose auditors have expertise in the customer’s industries. Overall, our results suggest that the supply chain is an important transmission channel of abnormal accruals, and auditor expertise serves to reduce information opaqueness during this process. Our paper contributes to the literature examining the impact of BWEs on firms’ financial performance and the role of auditors’ expertise in reducing information opaqueness in supply chain.
On the Lateral-Torsional Elastic Post-Buckling and Strength of Channel Steel Beams
Authors: Gonçalves Rodrigo
Published: October 2020

This paper aims at shedding new light on the elastic post-buckling behavior and strength (elastoplastic collapse) of steel channel section beams undergoing lateral-torsional (LT) buckling. This new insight is acquired using a two-node geometrically exact beam finite element developed by the author, which can handle large displacements, including torsion-related warping, Wagner effects, plasticity, residual stresses and arbitrary initial configurations (namely geometrical imperfections). Several cross-sections and loading/support conditions are analyzed. The results obtained show that the LT buckling behavior of channels is asymmetric, meaning that the direction of the geometric imperfection can influence significantly the strength of the beams. Moreover, it is demonstrated that the loading and support conditions play a major role, leading to a significant scatter of results which hinder the definition of a single buckling curve for design purposes. Nevertheless, in all cases considered, the buckling strengths obtained fall significantly above those predicted by the current version of Eurocode 3.
How the Accuracy and Confidence of Sensitivity Classification Affects Digital Sensitivity Review
Authors: Mcdonald Graham , Macdonald Craig , Ounis Iadh
Published: October 2020

Government documents must be manually reviewed to identify any
sensitive
information, e.g., confidential information, before being publicly archived. However, human-only sensitivity review is not practical for born-digital documents due to, for example, the volume of documents that are to be reviewed. In this work, we conduct a user study to evaluate the effectiveness of sensitivity classification for
assisting
human sensitivity reviewers. We evaluate how the accuracy and confidence levels of sensitivity classification affects the number of documents that are correctly judged as being sensitive (reviewer accuracy) and the time that it takes to sensitivity review a document (reviewing speed). In our within-subject study, the participants review government documents to identify real sensitivities while being assisted by three sensitivity classification
treatments
, namely
None
(no classification predictions),
Medium
(sensitivity predictions from a
simulated
classifier with a balanced accuracy (BAC) of 0.7), and
Perfect
(sensitivity predictions from a classifier with an accuracy of 1.0). Our results show that sensitivity classification leads to significant improvements (ANOVA,
p
< 0.05) in reviewer accuracy in terms of BAC (+37.9%
Medium
, +60.0%
Perfect
) and also in terms of F
2
(+40.8%
Medium
, +44.9%
Perfect
). Moreover, we show that assisting reviewers with sensitivity classification predictions leads to significantly increased (ANOVA,
p
< 0.05) mean reviewing speeds (+72.2%
Medium
, +61.6%
Perfect
). We find that reviewers do not agree with the classifier significantly more as the classifier’s confidence increases. However, reviewing speed is significantly increased when the reviewers agree with the classifier (ANOVA,
p
< 0.05). Our in-depth analysis shows that when the reviewers are not assisted with sensitivity predictions, mean reviewing speeds are 40.5% slower for sensitive judgements compared to not-sensitive judgements. However, when the reviewers
are
assisted with sensitivity predictions, the difference in reviewing speeds between sensitive and not-sensitive judgements is reduced by ˜10%, from 40.5% to 30.8%. We also find that, for sensitive judgements, sensitivity classification predictions significantly increase mean reviewing speeds by 37.7% when the reviewers agree with the classifier’s predictions (
t
-test,
p
< 0.05). Overall, our findings demonstrate that sensitivity classification is a viable technology for assisting human reviewers with the sensitivity review of digital documents.
Passages
Authors: Groce Alex
Published: October 2020

Robert K. Merton's On the Shoulders of Giants: A Shandean Postscript - The Post-Italianate Edition, or, henceforth, OTSOG, is our (ostensible) topic for this issue's Passages column.

[[What follows after this double-bracketed 'introduction' is a failure, an attempt to recommend this book by, in miniature, aping its style and form. In my opinion, it doesn't really work. I ask the reader who has ever enjoyed a book read because it was recommended in this column to bear with me through it, however, for there is a point to be made, and a remarkable book to recommend.