bluuebunny/crossref_metadata_2025 huggingface dataset:
Multidisciplinary Optimization-Enabled Design Automation and Optimization for Blowout Preventer Pipe Rams
Authors: Song Fei , Li Ke , Stephan Rivas Caroline , Bieneman Konstantin , Yap Thomas
Published: February 2021

A blowout preventer (BOP) is a large valve that encases an oil well on the surface. The valve may be closed while drilling if overpressure from a reservoir causes formation fluids such as oil and natural gas to back up within the wellbore and endanger the rig. A pipe ram is one of the critical components in the BOP system, which is designed to seal around a drill pipe, restricting the flow in the annulus between the outside of the drill pipe and the wellbore. The pipe ram design family, which contains hundreds of pipe ram designs, intends to cover different configurations to suit a variety of dill pipe sizes. To assure their structural integrity under service loads, these pipe rams need to be designed to meet the stress requirements per the American Petroleum Institute (API) Specification 16A and ASME (American Society of Mechanical Engineers) Boiler and Pressure Vessel Code Section VIII, Division 2. With a conventional manual design workflow, it would take a significant amount of time and effort to complete all the designs for the product family with code compliance. Therefore, a scalable solution is highly desirable for delivery of customer-needed ram blocks with much shorter lead time. MDO (Multi-Disciplinary Optimization) involves multi-code integration, CAE (Computer-Aided Engineering) workflow automation, design space exploration, and optimization. MDO-enabled, automated design optimization is becoming increasingly popular in both scientific and engineering communities.

In this paper, a methodology for integration of CAD (Computer Aided Design), FEA (Finite Element Analysis), cost, and optimization packages to enable FEA automation and design optimization is presented. A BOP pipe ram is adopted as the use case. The ram block geometry was parameterized before being imported into an FEA package. The FEA workflow was automated such that once a set of geometric parameters are given, the preprocessing, solving, and postprocessing steps can be automatically completed. As part of the FEA postprocessing, stress linearization analysis per the API and ASME BPVC codes has also been automated, which had never been done in the past. A manufacturing cost analysis package can also be used to consume the parameterized geometry for automatic manufacturability assessment and cost predictions. The stress analysis and cost analysis workflows are conducted separately but also orchestrated by an MDO package. Reports that contain the analysis results are sequentially generated for various design permutations. The MDO-enabled automated design and cost analysis approach could substantially enhance efficiency and consistency in performing FEA and cost studies and producing analysis reports. It is also the backbone for automated design optimization, which could significantly improve the product performance and reliability and, meanwhile, minimize the development and product cost.
Mast System Design for Autonomous Tick Collection Robot
Authors: Harrison Moretto Caroline “Niki” , Dong Janet , Qiu Yesiliang
Published: February 2021

This paper discusses the design and testing of a mast system constructed to collect ticks from rugged terrain in remote areas via a mobile robot. The goal of this project is to develop a robotic tick collection mast that can be used to collect ticks in diverse tick habitats, such as shrubs, weeds, and grass of various heights, and in different environmental conditions. The project focuses on locating the ideal design of the mast system, including materials and dimensions, types of mounting fixtures, and a center of gravity that ensures maximum tick collection without causing robot instability. The design was tested in the field and through simulations.

The optimum design uses a mast system with two fixtures, a drag mast and a flag mast, made from t-slotted aluminum. The drag mast holds strips lower to the ground to collect ticks from the short grass, and the flag mast holds strips in the air, along the side of the robot, to collect ticks from taller grass and shrubs. The mast system design does not impact the robot’s ability to traverse challenging terrain, cause the robot to lose traction, frequently become permanently entangled in the brush, or have any other detrimental effect on robot mobility.

The drag and flag mounts are two separate fixtures that are removable and adjustable along the horizontal and vertical axes to accommodate various terrain types. The strip attachment points are also adjustable horizontally to allow the rearrangement of strips for optimum tick collection in different tick habitats.

The strength and stability of the mast system were evaluated using stress and center of gravity simulations. The design’s performance was also analyzed in the field using three types of tests: flagging and dragging, traversing uneven ground, and ascending and descending hills. The flagging and dragging test ran the robot along the side of taller foliage to test for tangling or breakage. The uneven ground test examined the robot’s performance over the ground that was pitted and dimpled to assess stability. The angled ground test studied the robot’s ability to ascend and descend hills to ensure it did not tip in any direction.

A robotic solution with a mast system and flagging and dragging mounts protects humans from being infected with potential illnesses from bugs and insects carrying disease pathogens, injuries from traveling across rough ground, and harm due to exposure to the elements. Productivity is also increased, as a robot can remain in the field for an extended period. The mast system design captures ticks despite adverse conditions, is easily interchangeable, and does not hinder tick collection.
Instability Study of Repetitive Nanosecond Pulsed Discharge Plasma in a Plasma Assisted Burner
Authors: Zare Saeid , Askari Omid
Published: February 2021

High velocity flows, as in aerospace applications require special techniques to stabilize and ignite diffusion flames. Some techniques focus on changing parameters like geometry, conditions of the flow, or fuel composition, but these techniques are usually too expensive or impossible due to major changes in the system. On the other hand, some techniques focus on generating a region of charged/excited species and active radicals upstream of the flame. That can substantially enhance the flame stability even under high strain rate or at lean-limit-flammability conditions. Repetitive nanosecond pulsed (RNP) discharge plasma is a nonthermal plasma technique with some remarkable potential to improve stability and ignitability of high velocity diffusion flames. This technique was used in previous papers in a plasma assisted coaxial inverse diffusion burner and showed some promising results by reducing the lift-off height and delaying detachment and blowout conditions. This burner is prepared to employ the discharges at the burner nozzle and simulate a single element of a multi-element methane burner. However, effectiveness of high-voltage high-frequency RNP plasma was limited by the mode of the discharge. During the tests, three different modes were observed at different combinations of plasma and flow conditions. These three modes are low energy corona, uniformly distributed plasma, and high-energy point-to-point discharge. Among these three, only well-distributed plasma significantly improved the flame. In other cases, plasma deployment was either ineffective or in some cases adversely affected the flame by producing undesirable turbulence advancing blow out. As a result, a comprehensive study of these modes is required. In this work, the transition between these three modes in a jet flame was discussed. It has been expressed as a function of plasma conditions, i.e. peak discharge voltage and discharge frequency. It was shown that increasing flow speed delays increases the voltage and frequency at which transition occurs from low-energy corona discharge to well distributed plasma discharge. Subsequently, the effective plasma conditions are thinned. On the other hand, by increasing the frequency of nanosecond discharges, the chance of unstable point-to-point discharges is decreased. In contrast, the discharge peak voltage causes two different consequences. If it is too low, the pulse intensity is too week that the system will experience no visible plasma discharges or the discharges will not pass the low-energy corona, no matter how high the frequency is. If too high, it will enhance the chance of point-to-point discharges and limits the stabilization outcome of the system. Therefore, an optimal region is found for peak discharge voltage.
Experimental and Numerical Investigation of Natural Convection Heat Transfer From Horizontal Rectangular Plate Fin Pin Fin Arrays
Authors: Dingare Sunil V. , Sane Narayan K. , Kulkarni Ratnakar R.
Published: February 2021

Fins are commonly employed for cooling of electronic equipment, compressors, Internal Combustion engines and for heat exchange in various heat exchangers. In short fin (length to height ratio, L/H = 5) arrays used for natural convection cooling, a stagnation zone forms at the central portion and that portion is not effective for carrying away heat. An attempt is made to modify plate fin heat sink geometry (PFHS) by inserting pin fins in the channels formed between plate fins and a plate fin pin fin heat sink (PFPFHS) is constructed to address this issue. An experimental setup is developed to validate numerical model of PFPFHS. The three-dimensional elliptic governing equations were solved using a finite volume based computational fluid dynamics (CFD) code. Fluent 6.3.26, a finite volume flow solver is used for solving the set of governing equations for the present geometry. Cell count based on grid independence and extended domain is used to obtain numerical results. Initially, the numerical model is validated for PFHS cases reported in the literature. After obtaining a good agreement with results from the literature, the numerical model for PFHS is modified for PFPFHS and used to carry out systematic parametric study of PFPFHS to analyze the effects of parameters like fin spacing, fin height, pin fin diameter, number of pin fins and temperature difference between fin array and surroundings on natural convection heat transfer from PFPFHS. It is observed that it is impossible to obtain optimum performance in terms of overall heat transfer by only concentrating on one or two parameters. The interactions among all the design parameters must be considered. This thesis presents Experimental and Numerical study of natural convection heat transfer from horizontal rectangular plate fin and plate fin pin fin arrays. The parameters of study are fin spacing, temperature difference between the fin surface and ambient air, fin height, pin fin diameter, number of pin fins and method of positioning pin fins in the fin channel. Experimental set up is validated with horizontal plate standard correlations. Results are generated in the form of variation in average heat transfer coefficient (ha), base heat transfer coefficient (hb), average Nusselt number (Nua) and base Nusselt number (Nub).

Total 512 cases are studied numerically and finally an attempt is made to correlate the Nusselt Number (Nu), Rayleigh Number (Ra), increase in percentage by inserting pin fins (% Area), ratios like spacing to height (S/H) and L/H obtained in the present study.
Experimental Validation of Mushy Zone Constant for Modeling of Solidification/Melting for Thermal Energy Storage Applications
Authors: Prabhu Vinit V. , Languri Ethan , Nawaz Kashif
Published: February 2021

The thermal energy storage (TES) systems use phase change materials (PCM’s) for storage and release of thermal energy. A lot of research is being conducted in recent times for fast, efficient storage and release of thermal energy using phase change materials in order to utilize the vast amount of latent heat available at constant temperature during phase change process. The numerical modeling for solidification and melting of PCM is employed in various commercial software and applied for different applications which include the solidification or melting. In the numerical simulation of phase change process, the solidification and melting are modelled using enthalpy-porosity method developed some researchers previously. The mushy zone constant is an important factor in this method which is used in the governing equations as a source term to model the melt front. The aim of this study is to determine the role of mushy zone constant on the solidification/melting behavior of phase change material numerically and validate the results with the experiments. The melting behavior of PCM is studied in this paper. The experimental setup consisting of a cubical container of dimensions 3″ × 3″ × 3″ filled with PCM was considered. The box was heated from one side and insulated from other sides so that the heat supplied is transferred to the PCM to melt it completely. The melting behavior of PCM was observed by capturing images at specific time intervals with the help of a camera. The camera was placed in such a way with minimum parallax error. These results are validated with previous numerical study in which the mushy zone constant was varied from 104 to 106 to determine the optimum value. The PCM used in this study is a paraffin wax material having a melting point of 48 °C. The propagation of melt front is plotted at different time steps and validated with the numerical results. The propagation of melt front is observed to be different for each of the mushy zone constant values. It was observed that the melting for higher values of mushy zone constant is observed to be similar to the experiment for the initial part of melting. Also, the melting rate speeds up and is observed to be similar to melting in the lower values of mushy zone constant. This paper aims to be a starting point to determine the optimum mushy zone constant for different factors affecting the melting behavior such as different materials, temperature difference.
Study of Tapping Process of Ti6Al4V Using Finite Element (FE) Simulation
Authors: Daneji Ali , Pervaiz Salman , Kannan Sathish
Published: February 2021

Finite element (FE) assisted numerical modeling approach is known as a popular approach to predict the machining performance of different machining operations. Tapping operation is a well-known manufacturing process that is used to cut threads efficiently. In the automotive and aerospace applications, precisely machined tapped holes are required in the small size deep holes. Tapping process creates thread in the hole and make it ready for fastening with other mating components. Tapping operation is considered as one of the most complex machining operations due to the presence of multi-flutes and multi-land involvement between the workpiece and cutter materials. The outcome of the tapping process results in the generation of threads and accepted as one of the most commonly employed in fastening methods for the joining of different machine components. Literature revealed that tapping process has been very rarely investigated using computational modeling approaches, as most of the available studies are experimental in nature. The experimental work for tapping operation can be very time and cost consuming because of the expensive fabrication of the cutting tools. It has also been observed experimentally that minor change in the threading profiles can generate significant difference in the cutting torque. A possible solution is to analyse the whole tapping operation using finite element (FE) assisted numerical simulation. Similarly, there will be limitation towards experiments if the workpiece material is expensive and difficult to cut.

It is a common observation in metal cutting industry that most of the times cutting tap results in breakage when exposed to the higher magnitude of torque. The current study is aimed on the finite element based computational investigations on the tapping process using Ti6Al4V as a workpiece material. High hot hardness and low thermal conductivity of the Ti6Al4V also plays a significant role towards the poor machining performance of the threading tool. Ti6Al4V is most commonly employed in the engineering applications where high strength to weight ratio and ability of operate at higher temperatures is required. Ti6Al4V is mainly utilized in the automotive, aerospace, biomedical and petrochemical industries. It has been identified that tapping operation is very rarely studied machining operation in the metal cutting scientific community. Different tapping process conditions were investigated computationally using finite element (FE) approach and as a result cutting forces, torques and power consumed were observed. The study provides a useful understanding towards the tapping process mechanics with respect to different cutting parameters.
Numerical Study of the Unsteady Flow Inside a Centrifugal Fan and its Downstream Pipe Using Detached Eddy Simulation
Authors: Cai Jian-Cheng , Zhang Jia-Qi , Yang Can
Published: February 2021

The 3-D unsteady turbulent flow inside a centrifugal fan and its downstream pipe is investigated at the best efficiency point (BEP) flow rate using the computational fluid dynamics (CFD) package ANSYS FLUENT. The impeller with an outlet diameter of 400 mm has 12 forward curved blades. The computational domain comprises four parts: the inlet part, the impeller, the volute, and the downstream pipe. The flow domain was meshed in ANSYS ICEM-CFD with structured hexahedron cells, and nearly 9 million cells were used. The Detached Eddy Simulation (DES) turbulence modelling approach was employed with this fine enough mesh scheme. The impeller was set as the rotating domain at a speed of 2900 rpm. A sliding mesh technique was applied to the interfaces in order to allow unsteady interactions between the rotating impeller and the stationary parts; the unsteady interactions generate pressure fluctuations inside the centrifugal fan. One impeller revolution is divided into 2048 time steps, in order to capture the transient flow phenomena with high resolution. Monitoring points were set along the volute casing profile, and along the downstream pipe centerline. When the numerical simulation became stable after several impeller revolutions, the statistics of the unsteady flow was initiated with a total of 16384 time steps (8 impeller revolutions) data. The time history data of the pressure and velocity magnitude at the monitoring points were saved and with Fourier transform applied to obtain the frequency spectra.

The time-averaged flow fields show clearly the static pressure rises gradually through the impeller, and further recovers from the velocity in the volute, and decreases gradually along the downstream pipe due to the friction. The mean pressure at the pressure side of the impeller blade is larger than it at the suction side, forming the circumferential nonuniform flow pattern. Owing to the forward-curved blades, large velocity region exists around the impellor exit, and the maximum velocity near the trailing edge can reach 1.5u2, where u2 is the circumferential velocity at the impeller outlet.

The root mean square (rms) value distribution of pressure fluctuations show that most parts inside the centrifugal fan undergo large pressure fluctuation with the magnitude about 10% of the reference dynamic pressure pref = 0.5ρu22; the maximum value locating at the tongue tip can reach 30% of pref. The pressure fluctuation magnitude decreases quickly along the outlet pipe: after 5D (D is the outlet pipe diameter) the magnitude is 0.5% of pref. The pressure and velocity fluctuation spectra at the monitoring points in the volute show striking discrete components at the blade-passing frequency (BPF) and its 2nd, 3rd harmonics. The BPF component has the maximum value of 15% of pref in the tongue region, and it decreases dramatically along the downstream pipe with the amplitude less than 0.2% of pref after 5D distance.
Investigation of Two-Phase Flow and Heat Transfer Inside Rotational Paper Dryers Using Three Different Multiphase Computational Models
Authors: Majeed Hamed , Barboza Pereira Victor , Wang Ting , D’Amico Joseph V. , Kononchek Chris
Published: February 2021

The paper industry uses cylinder dryers that employ steam to heat the paper web moving over the cylinder outer walls. As steam condenses, the condensate is accumulated inside the cylinder dryers. The condensate is evacuated using either stationary or rotary siphons. The form of condensate motion occurring inside the cylinder can be puddling, cascading or rimming depending on the size of the cylinder dryer, the rotating speed, the amount of condensate, and the surface finish of the cylinder dryer inner wall with or without ribs or grooves. The behavior of the condensate inside the cylinder dryers affects the heat transfer through the cylinder wall, the torque and power requirements of the dryer, and the performance of the condensate evacuation via siphons. To help improve the drying performance, it is important to understand the fundamental thermal-fluid physics in the rotational dryer. Thus, the objectives of this study are (a) to investigate the dynamic two-phase flow and heat transfer behavior inside the rotational paper dryer at different rotational speeds; (b) to employ three different multiphase computational models, the Volume of Fluid (VOF) model, the Mixture model, and the Eulerian-Eulerian (E-E) model, and compare their results. The results show that the E-E model better captures the physics of condensate behavior inside the dryer. It also predicts very well the rimming speed in comparison with the empirical correlation although it takes longer computational time than the VOF model. The mixture model doesn’t adequately capture the cascade and rimming physics due to excessive liquid dispersion. Based on the results, the categorization of the thermal-flow behavior of the liquid layer is expanded from the traditional three phases to five phases: puddling, transitional cascading, cascading, transitional rimming, and steady rimming. A detailed analysis of the rotating liquid layer behavior and its corresponding wall heat transfer passing through each phase is presented. Generally, the heat transfer increases during the initial puddling period, followed by oscillatory attenuation during the cascade period, finally reaches steady state after rimming is achieved.
Generative adversarial networks for the design of acoustic metamaterials
Authors: Gurbuz Caglar , Kronowetter Felix , Dietz Christoph , Eser Martin , Schmid Jonas , Marburg Steffen
Published: February 2021

Metamaterials are attracting increasing interest in the field of acoustics due to their sound insulation effects. By periodically arranged structures, acoustic metamaterials can influence the way sound propagates in acoustic media. To date, the design of acoustic metamaterials relies primarily on the expertise of specialists since most effects are based on localized solutions and interference. This paper outlines a deep learning-based approach to extend current knowledge of metamaterial design in acoustics. We develop a design method by using conditional generative adversarial networks. The generative network proposes a cell candidate regarding a desired transmission behavior of the metamaterial. To validate our method, numerical simulations with the finite element method are performed. Our study reveals considerable insight into design strategies for sound insulation tasks. By providing design directives for acoustic metamaterials, cell candidates can be inspected and tailored to achieve desirable transmission characteristics.
Strong self-trapping by deformation potential limits photovoltaic performance in bismuth double perovskite
Authors: Wu Bo , Ning Weihua , Xu Qiang , Manjappa Manukumara , Feng Minjun , Ye Senyun , Fu Jianhui , Lie Stener , Yin Tingting , Wang Feng , Goh Teck Wee , Harikesh Padinhare Cholakkal , Tay Yong Kang Eugene , Shen Ze Xiang , Huang Fuqiang , Singh Ranjan , Zhou Guofu , Gao Feng , Sum Tze Chien
Published: February 2021

Bismuth double perovskite Cs
2
AgBiBr
6
strong electron–acoustic phonon interactions derail its photovoltaic aspirations.
Controlled generation of luminescent centers in hexagonal boron nitride by irradiation engineering
Authors: Fischer M. , Caridad J. M. , Sajid A. , Ghaderzadeh S. , Ghorbani-Asl M. , Gammelgaard L. , Bøggild P. , Thygesen K. S. , Krasheninnikov A. V. , Xiao S. , Wubs M. , Stenger N.
Published: February 2021

Irradiation engineering on hexagonal boron nitride reveals insights into the microscopic nature of quantum emitters.
Microscopic structure and dynamics study of granular segregation mechanism by cyclic shear
Authors: Li Zhifeng , Zeng Zhikun , Xing Yi , Li Jindong , Zheng Jie , Mao Qinghao , Zhang Jie , Hou Meiying , Wang Yujie
Published: February 2021

X-ray tomography study reveals that sheared granular mixtures with size difference segregate under convection and arching effects.
Intranasal fusion inhibitory lipopeptide prevents direct-contact SARS-CoV-2 transmission in ferrets
Authors: de Vries Rory D. , Schmitz Katharina S. , Bovier Francesca T. , Predella Camilla , Khao Jonathan , Noack Danny , Haagmans Bart L. , Herfst Sander , Stearns Kyle N. , Drew-Bear Jennifer , Biswas Sudipta , Rockx Barry , McGill Gaël , Dorrello N. Valerio , Gellman Samuel H. , Alabi Christopher A. , de Swart Rik L. , Moscona Anne , Porotto Matteo
Published: February 2021

Halting transmission

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) glycoprotein binds to host cells and initiates membrane fusion and cell infection. This stage in the virus life history is currently a target for drug inhibition. De Vries
et al.
designed highly stable lipoprotein fusion inhibitors complementary to a conserved repeat in the C terminus of S that integrate into host cell membranes and inhibit conformational changes in S necessary for membrane fusion. The authors tested the performance of the lipoproteins as a preexposure prophylactic in a ferret-to-ferret transmission study. Intranasal administration of the peptide 2 days before cohousing with an infected ferret for 24 hours completely protected animals in contact from infection and showed efficacy against mutant viruses. Because ferrets do not get sick from SARS-CoV-2, disease prevention could not be tested in this model.

Science
, this issue p.
1379
A 2-Pyridone Amide Inhibitor of Transcriptional Activity in Chlamydia trachomatis
Authors: Núñez-Otero Carlos , Bahnan Wael , Vielfort Katarina , Silver Jim , Singh Pardeep , Elbir Haitham , Almqvist Fredrik , Bergström Sven , Gylfe Åsa
Published: February 2021

Chlamydia trachomatis
is a strict intracellular bacterium that causes sexually transmitted infections and eye infections that can lead to lifelong sequelae. Treatment options are limited to broad-spectrum antibiotics that disturb the commensal flora and contribute to selection of antibiotic-resistant bacteria.
Consecutive Antibiotic Shortages Highlight Discrepancies between Microbiology and Prescribing Practices for Intra-abdominal Infections
Authors: Park Stacy C. , Gillis-Crouch Grace R. , Cox Heather L. , Donohue Lindsay , Morse Rena , Vegesana Kasi , Mathers Amy J.
Published: February 2021

Piperacillin-tazobactam (TZP) is frequently used for intra-abdominal infection (IAI). Our institution experienced consecutive shortages of TZP and cefepime, providing an opportunity to review prescribing patterns and microbiology for IAI.
Complete Genome Sequence of
Thiohalobacter
sp. Strain COW1, Isolated from Activated Sludge Treating Coke Oven Wastewater
Authors: Miyazaki Kentaro , Suenaga Hikaru , Oshiki Mamoru , Kawano Shuichi , Fukushima Toshikazu
Published: February 2021

A thiocyanate-degrading bacterium,
Thiohalobacter
sp. strain COW1, was isolated from activated sludge treating coke oven wastewater, and the complete genome sequence was determined. COW1 contained a single circular chromosome (3.23 Mb; G+C content, 63.4%) in which 2,788 protein-coding genes, 39 tRNA genes, and 3 rRNA genes were identified.
Complete Genome Sequence of a Clinical
Campylobacter
Isolate Identical to a Novel
Campylobacter
Species
Authors: Duim Birgitta , van der Graaf-van Bloois Linda , Timmerman Arjen , Wagenaar Jaap A. , Flipse Jacky , Wallinga Janny , Bloembergen Peter , Miller William G. , Zomer Aldert L.
Published: February 2021

Here, we present the complete genome sequence of a
Campylobacter
strain isolated in the Netherlands from a patient with gastroenteritis. The strain showed >98% sequence identity to the novel
Campylobacter
species sequence recently recovered from metagenomic data, isolated from breastfed infants with diarrheal disease, and named “
Candidatus
Campylobacter infans.”
Genome Sequences and Phylogeny of Two Duck Hepatitis B Viruses
Authors: Apolônio Silva de Oliveira Daniel , Debing Yannick , Dieryck Ines , Lyimu Wilfred Michael , Paeshuyse Jan
Published: February 2021

Duck hepatitis B virus (DHBV) infection in Pekin ducks is a model for human hepatitis B. Sequence variations may contribute to host therapy responses against the virus. We provide full genome sequences of two DHBVs from France, their phylogenetic classification, and their sequence variability.
Draft Genome Sequence of Weissella paramesenteroides STCH-BD1, Isolated from Ensiled Sorghum bicolor
Authors: Baugh Ashley V. , Howarth Thomas M. , West Katrina L. , Kerr Lydia E. J. , Love John , Parker David A. , Fedenko Jeffrey R. , Tennant Richard K.
Published: February 2021

Weissella paramesenteroides
has potential as an industrial biocatalyst due to its ability to produce lactic acid. A novel strain of
W. paramesenteroides
was isolated from ensiled sorghum. The genome was sequenced using a hybrid assembly of Oxford Nanopore and Illumina data to produce a 2-Mbp genome and 22-kbp plasmid sequence.
Complete Genome Sequence of Chesapeake Bay Winter
Synechococcus
sp. Strain CBW1107, a Member of Subalpine Cluster II
Authors: Fucich Daniel , Xu Yongle , Sosa Ana , Zhang Rui , Jiao Nianzhi , Chen Feng
Published: February 2021

Here, we report the complete genome sequence of psychrotolerant
Synechococcus
sp. strain CBW1107, which was isolated from the Chesapeake Bay in winter. CBW1107 is a member of picocyanobacterial subalpine cluster II and exhibits greater cold tolerance, compared to most coastal and marine
Synechococcus
strains.
Type-5 Bartter syndrome presenting with metabolic seizure in adulthood
Authors: Hussain Aqeel , Atlani Mahendra , Goyal Abhishek , Khurana Alkesh Kumar
Published: February 2021

Bartter syndrome is a very rare and heterogeneous disease with variable age of onset and symptom severity. Genotypically they have inherited disorders of the thick ascending limb in the renal tubular system, which manifest phenotypically as electrolyte imbalance due to loss of sodium, chloride and potassium. Gain of function mutations in the calcium-sensing receptor has been described in some patients with Bartter’s syndrome (type-5 Bartter syndrome or autosomal dominant hypocalcaemia with Bartter syndrome) associated with hypocalcaemia and hypercalciuria differentiating it from Gitelman syndrome. This phenotype has been reported to present in adulthood with metabolic abnormalities. We present a case of a middle-aged woman who presented with metabolic seizures and on evaluation was found to have profound electrolyte abnormalities which were corrected with supplements and led to the resolution of symptoms.
Foreign body perforation of the distal ileum: an unusual cause of right iliac fossa pain managed via single incision laparoscopic surgery (SILS) approach
Authors: Bonomaully Matthew R , Haque Zia , Rao Milind
Published: February 2021

A 61-year-old woman was seen by the emergency general surgical team with a 2-week history of right iliac fossa pain. Imaging revealed the possibility of a distal ileum perforating foreign body. Using a single incision laparoscopy surgery (SILS) approach, this diagnosis was confirmed at operation. This emerging technique meant a much smaller incision could be used than traditional exploratory laparotomy, with the benefit of less postoperative pain and a faster recovery. This case highlights an uncommon cause for abdominal pain and the importance of close liaison with radiologists and the low threshold for use of laparoscopy as a diagnostic tool. We advocate the use of SILS in the emergency setting for appropriate cases.
Anaesthetic management in a patient requiring one lung ventilation during COVID-19 pandemic
Authors: Teah Ming Kai , Yap Kent Yoon , Ismail Abdul Jabbar , Yeap Tat Boon
Published: February 2021

Placement of a double-lumen tube to achieve one lung ventilation is an aerosol-generating procedure. Performing it on a patient with COVID-19 will put healthcare workers at high risk of contracting the disease. We herein report a case of its use in a patient with traumatic diaphragmatic rupture, who was also suspected to have COVID-19. This article aims to highlight the issues, it presented and ways to address them as well as the perioperative impact of personal protective equipment.
Factors affecting health care users’ first contact with primary health care facilities in north eastern China, 2008–2018
Authors: Liao Ran , Liu Yaqian , Peng Shunzhuang , Feng Xing Lin
Published: February 2021

Background

China set out the vision to establishing a hierarchical medical system, with primary health care (PHC) facilities serving health care users’ first contact. Common ailments were listed, supported by a series of auxiliary policy measures. We aim to assess whether these policies were effective to prompt users’ preference to PHCs within these contexts.

Methods

Using data from three waves of National Health Service Survey, we examined trends in care users’ first contact with PHC facilities in Jilin, a north eastern province, during 2008–2018. We analysed trends and factors affecting care users’ choices, stratified by type of diseases and urban–rural settings.

Results

From 38 823 respondents, the survey identified 3302 health care users who sought outpatient care. 54.92% and 82.49% with diseases recommended to PHC, in urban and rural Jilin, respectively, contacted PHC facilities first. While 33.51% and 61.19% with diseases not recommended to PHC did so. Care users’ first contact with PHC facilities followed an inverse U shape during 2008–2018. Such trends were more profound among care users with hypertension and/or diabetes. Neither social health insurance coverage nor contracting with family doctors was associated with care users’ first contacts. Only 1.25% care users had referral experiences. Low perceived quality was the main barrier to choose PHC facilities.

Conclusion

Health care users sought PHC in a chaotic manner in Jilin. None of the recent efforts seemed effective in prompting their preference to PHC facilities. Without levering quality of PHC, an effective hierarchical medical system could be hardly forged in China.
Does psychological distress directly increase risk of incident cardiovascular disease? Evidence from a prospective cohort study using a longer-term measure of distress
Authors: Welsh Jennifer , Banks Emily , Joshy Grace , Butterworth Peter , Strazdins Lyndall , Korda Rosemary J
Published: February 2021

Objective

Cardiovascular disease (CVD) incidence is elevated among people with psychological distress. However, whether the relationship is causal is unclear, partly due to methodological limitations, including limited evidence relating to longer-term rather than single time-point measures of distress. We compared CVD relative risks for psychological distress using single time-point and multi-time-point assessments using data from a large-scale cohort study.

Design

We used questionnaire data, with data collection at two time-points (time 1: between 2006 and 2009; time 2: between 2010 and 2015), from CVD-free and cancer-free 45 and Up Study participants, linked to hospitalisation and death records. The follow-up period began at time 2 and ended on 30 November 2017. Psychological distress was measured at both time-points using Kessler 10 (K10), allowing assessment of single time-point (at time 2: high (K10 score: 22–50) vs low (K10 score: <12)) and multi-time-point (high distress (K10 score: 22–50) at both time-points vs low distress (K10 score: <12) at both time-points) measures of distress. Cox regression quantified the association between distress and major CVD, with and without adjustment for sociodemographic and health-related characteristics, including functional limitations.

Results

Among 83 906 respondents, 7350 CVD events occurred over 410 719 follow-up person-years (rate: 17.9 per 1000 person-years). Age-adjusted and sex-adjusted rates of major CVD were elevated by 50%–60% among those with high versus low distress for both the multi-time-point (HR=1.63, 95% CI 1.40 to 1.90) and single time-point (HR=1.53, 95% CI 1.39 to 1.69) assessments. HRs for both measures of distress attenuated with adjustment for sociodemographic and health-related characteristics, and there was little evidence of an association when functional limitations were taken into account (multi-time-point HR=1.09, 95% CI 0.93 to 1.27; single time-point HR=1.14, 95% CI 1.02 to 1.26).

Conclusion

Irrespective of whether a single time-point or multi-time-point measure is used, the distress–CVD relationship is substantively explained by sociodemographic characteristics and pre-existing physical health-related factors.
Effect of intensive treatment for schistosomiasis on immune responses to vaccines among rural Ugandan island adolescents: randomised controlled trial protocol A for the ‘POPulation differences in VACcine responses’ (POPVAC) programme
Authors: Nkurunungi Gyaviira , Zirimenya Ludoviko , Nassuuna Jacent , Natukunda Agnes , Kabuubi Prossy N , Niwagaba Emmanuel , Oduru Gloria , Kabami Grace , Amongin Rebecca , Mutebe Alex , Namutebi Milly , Zziwa Christopher , Amongi Susan , Ninsiima Caroline , Onen Caroline , Akello Florence , Sewankambo Moses , Kiwanuka Samuel , Kizindo Robert , Kaweesa James , Cose Stephen , Webb Emily , Elliott Alison M
Published: February 2021

Introduction

Several licensed and investigational vaccines have lower efficacy, and induce impaired immune responses, in low-income versus high-income countries and in rural, versus urban, settings. Understanding these population differences is essential to optimising vaccine effectiveness in the tropics. We suggest that repeated exposure to and immunomodulation by chronic helminth infections partly explains population differences in vaccine response.

Methods and analysis

We have designed an individually randomised, parallel group trial of intensive versus standard praziquantel (PZQ) intervention against schistosomiasis, to determine effects on vaccine response outcomes among school-going adolescents (9–17 years) from ruralSchistosoma mansoni-endemic Ugandan islands. Vaccines to be studied comprise BCG on day ‘zero’; yellow fever, oral typhoid and human papilloma virus (HPV) vaccines at week 4; and HPV and tetanus/diphtheria booster vaccine at week 28. The intensive arm will receive PZQ doses three times, each 2 weeks apart, before BCG immunisation, followed by a dose at week 8 and quarterly thereafter. The standard arm will receive PZQ at week 8 and 52. We expect to enrol 480 participants, with 80% infected withS. mansoniat the outset.

Primary outcomes are BCG-specific interferon-γ ELISpot responses 8 weeks after BCG immunisation and for other vaccines, antibody responses to key vaccine antigens at 4 weeks after immunisation. Secondary analyses will determine the effects of intensive anthelminthic treatment on correlates of protective immunity, on waning of vaccine response, on priming versus boosting immunisations and onS. mansoniinfection status and intensity. Exploratory immunology assays using archived samples will enable assessment of mechanistic links between helminths and vaccine responses.

Ethics and dissemination

Ethics approval has been obtained from relevant ethics committes of Uganda and UK. Results will be shared with Uganda Ministry of Health, relevant district councils, community leaders and study participants. Further dissemination will be done through conference proceedings and publications.

Trial registration number

ISRCTN60517191.
Effect of intermittent preventive treatment for malaria with dihydroartemisinin-piperaquine on immune responses to vaccines among rural Ugandan adolescents: randomised controlled trial protocol B for the ‘POPulation differences in VACcine responses’ (POPVAC) programme
Authors: Natukunda Agnes , Nkurunungi Gyaviira , Zirimenya Ludoviko , Nassuuna Jacent , Oduru Gloria , Amongin Rebecca , Kabuubi Prossy N , Mutebe Alex , Onen Caroline , Amongi Susan , Nakazibwe Esther , Akello Florence , Kiwanuka Samuel , Kiwudhu Fred , Sewankambo Moses , Nsubuga Denis , Kizindo Robert , Staedke Sarah G , Cose Stephen , Webb Emily , Elliott Alison M
Published: February 2021

Introduction

Drivers of lower vaccine efficacy and impaired vaccine-specific immune responses in low-income versus high-income countries, and in rural compared with urban settings, are not fully elucidated. Repeated exposure to and immunomodulation by parasite infections may be important. We focus onPlasmodium falciparummalaria, aiming to determine whether there are reversible effects of malaria infection on vaccine responses.

Methods and analysis

We have designed a randomised, double-blind, placebo-controlled, parallel group trial of intermittent preventive malaria treatment versus placebo, to determine effects on vaccine response outcomes among school-going adolescents (9 to 17 years) from malaria-endemic rural areas of Jinja district (Uganda). Vaccines to be studied comprise BCG vaccine on day ‘zero’; yellow fever, oral typhoid and human papilloma virus vaccines at week 4; and tetanus/diphtheria booster vaccine at week 28. Participants in the intermittent preventive malaria treatment arm will receive dihydroartemisinin/piperaquine (DP) dosed by weight, 1 month apart, prior to the first immunisation, followed by monthly treatment thereafter. We expect to enrol 640 adolescents. Primary outcomes are BCG-specific interferon-γ ELISpot responses 8 weeks after BCG immunisation and for other vaccines, antibody responses to key vaccine antigens at 4 weeks after immunisation. In secondary analyses, we will determine effects of monthly DP treatment (versus placebo) on correlates of protective immunity, on vaccine response waning, on whether there are differential effects on priming versus boosting immunisations, and on malaria infection prevalence. We will also conduct exploratory immunology assays among subsets of participants to further characterise effects of the intervention on vaccine responses.

Ethics and dissemination

Ethics approval has been obtained from relevant Ugandan and UK ethics committees. Results will be shared with Uganda Ministry of Health, relevant district councils, community leaders and study participants. Further dissemination will be done through conference proceedings and publications.

Trial registration number

Current Controlled Trials identifier:ISRCTN62041885.
Association between early working life patterns, in publicly and privately owned companies, and the course of future sickness absence due to mental disorders: a cohort study in Catalonia (Spain)
Authors: Ayala-Garcia Amaya , Serra Laura , Ubalde-Lopez Monica
Published: February 2021

Objectives

To assess the relationship between early working life patterns, at privately and publicly held companies, and the course of sickness absence (SA) due to mental disorders.

Methods

Cohort study of workers aged 18–28 years, affiliated with the Spanish social security system, living in Catalonia, who had at least one episode of SA due to mental disorders between 2012 and 2014. Individual prior working life trajectories were reconstructed through sequence analysis. Optimal matching analysis was performed to identify early working life patterns by clustering similar individual trajectories. SA trajectories were identified using latent class growth modelling analysis. Finally, the relationship between early working life patterns and subsequent SA trajectories was assessed via multinomial logistic regression models.

Results

Among both men and women, four labour market participation (LMP) patterns were identified: stable permanent employment (reference group), increasing permanent employment, fluctuating employment and delayed employment. Among women, an increasing permanent employment pattern in early working life was related to a decrease of accumulated SA days over time (adjusted OR (aOR) 2.08; 95% CI 1.18 to 3.66). In men, we observed a trend towards a middle stable accumulation of SA days in those with fluctuating employment (aOR 1.25, 95% CI 0.57 to 2.74) or delayed employment (aOR 1.79; 95% CI 0.59 to 5.41). In both men and women, an early working life in big companies was related to a more favourable SA trajectory.

Conclusions

Early LMP patterns characterised by an increasing stability—decreased number of transitions between temporary contracts and lack of social security coverage towards permanent contracts—were related to a better future SA course due to mental diagnosis.
Longitudinal analysis of growth trajectories in young children of Chinese-born immigrant mothers compared with Australian-born mothers living in Victoria, Australia
Authors: Bolton Kristy A , Kremer Peter , Laws Rachel , Campbell Karen J , Zheng Miaobing
Published: February 2021

Background

Chinese immigrants are the third largest immigrant group in Australia. Little is known about growth trajectories of their offspring when moving to a Western country. The aim was to describe the growth trajectories between birth to 3.5 years in children of Chinese-born immigrant mothers compared with Australian-born mothers living in Victoria, Australia.

Methods

Ten nurse measured weights and lengths from birth to 3.5 years were used to examine growth trajectory using linear spline multilevel models. Five knot points were identified at visit 2 (0.5 months), visit 4 (2 months), visit 5 (4.5 months), visit 8 (18 months) and visit 9 (25 months).

Results

Ethnic disparities in growth trajectories between these two groups were revealed in models adjusted for birth weight, sex and level of socioeconomic disadvantage. Children of Chinese-born compared with Australian-born mothers revealed different growth rates and significant differences in predicted mean body mass index Z score (zBMI) at all time points from birth to 44 months, except for 12 months. Specifically, when compared with children of Australian-born mothers, children of Chinese-born mothers started with lower predicted zBMI from birth until 0.5 months, had a higher zBMI from 1 to 8 months and a lower zBMI from 12 to 44 months. Early and sharp acceleration of growth was also observed for children of Chinese-born mothers (0.5–2 months) when compared with children of Australian-born mothers (2–18 months).

Conclusion

Differences in growth trajectories exist between young children of Chinese-born and Australian-born mothers. Better understanding of these ethnically patterned growth trajectories is important for identifying key opportunities to promote healthy growth in early life.