bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Type of Soft Pneumatic Torsional Actuator With Helical Chambers for Flexible Machines
Authors: Xiao Wei , Hu Dean , Chen Weixiong , Yang Gang , Han Xu
Published: August 2020

Soft pneumatic actuators (SPAs) that can twist dominantly provide a promising solution for the design of soft robots due to their flexibility, compliance, and easy fabrication. However, the torsional SPAs also face challenges such as overpressure risk and small torsion angle. To tackle those challenges, a new type of torsional SPAs is designed based on the reversible, cooperative buckling of elastomer, which yields a torsion angle of 1.94 deg/mm and an output torque of 26 N .mm with a secure operation pressure. Moreover, this actuator can achieve a wide range of torsional motion by varying the structure parameters, including the height of actuators and the pitch of helical chambers. The relationship between structure parameters and actuator performance is investigated experimentally, and experimental results show that the torsion angle and output torque increase with the height growing from 20 to 44 mm, while decrease with the pitch rising from 75 to 150 mm. The effect of different materials used for constructing the actuator is also studied numerically, and results show that the output torque can be improved by changing the materials. Additionally, several soft machines constructed by utilizing the actuators as a torsional joint are able to perform different manipulating tasks, such as screwing the light bulb, grasping and rotating objects. The actuator developed in this paper is capable of extending the researches on SPAs and offering an alternative for the actuation of soft machines.
Fluid Flow Mode of Nugget in Magnetically Assisted Resistance Spot Welding With Unequal Thickness Plates: Modeling and Experiments
Authors: Ao Sansan , Huang Yifei , Du Huimin , Luo Zhen
Published: August 2020

The nugget offset is the main challenge in the resistance spot welding (RSW) of unequal thickness plates. Magnetically assisted resistance spot welding (MA-RSW) is a potential new process to reduce the nugget offset ratio. Aiming at analyzing the fluid flow mode of the MA-RSW with unequal thickness plates, a multi-physics finite element model, including distortion field, thermal field, electric field, magnetic field, and fluid field, was created. The experimental validation verified the accuracy of the model. The connection between magnetic fields and nugget shape was analyzed. The results show that the fluid flow modes in the MA-RSW are composed of two parts, namely, the circumferential flow in the horizontal section and the approximately mirror-symmetrical flow in the vertical section. The circumferential motion is intensified with increasing magnetic flux density, and thus, the liquid metals with higher magnetic flux density tend to expand toward the solid–liquid interface, leading to nugget growth in these areas. Finally, based on the numerical results, a process of minimizing the nugget offset is proposed. The experimental results indicate that the proposed process can improve the nugget offset in RSW of unequal thickness plates.
Hydrogen Deflagration Analysis in THAI Experiments Using MELCOR Code
Authors: Flores y Flores Alain , Mazzini Guido
Published: August 2020

The Research Center Řež (CVŘ) is developing a methodology to simulate nuclear power plants under accidental conditions. A particular effort is focused in the severe accident phenomenology where hydrogen deflagration carries a critical issue for the containment integrity, such as Fukushima Daiichi accident. For this purpose, the Thermal-hydraulics, hydrogen, aerosol and iodine (THAI) experimental campaigns are chosen due to the several tests involved in different conditions. THAI containment test facility is used to open questions concerning the behavior of hydrogen, iodine, and aerosols in the containment of water-cooled reactors during severe accidents.The Fukushima Daiichi Accident demonstrates that the hydrogen deflagration could lead to a significant containment damage. For this reason, a particular attention is given to the hydrogen deflagration scenario. All simulations are prepared and modeled in melcor 2.1. The results obtained showed a strong influence related to some factors such as: the nodalization pattern, control volumes (CVs) number, flow paths (FPs) number, and time-step. In order to assess the THAI model with the THAI final reports, a sensitivity analysis focused on those parameters was performed, which developed four different models with different nodalization.
An Integrated I2C Sensor Network for Transcatheter Heart Valves
Authors: Secord Thomas W. , Koerner Lucas J. , Kopas Robert J.
Published: August 2020

Transcathether aortic heart valve replacement (TAVR) is a widespread approach to treating patients with severe aortic stenosis. A TAVR implant is ideally positioned to access numerous clinically relevant signals including arterial blood pressure, pulse wave velocity, electrocardiogram (ECG), patient motion, heart rate, respiration, and blood oxygenation. Unlike medical devices such as pacemakers, TAVR implants are purely mechanical structures with no sensing capabilities. In this work, we address this unmet clinical need by incorporating an Inter-Integrated Circuit (I2C) sensor network within a TAVR stent frame and designing sensor modules that can physically connect to the network at various landing zones. To illustrate this approach, we designed and built a sensor circuit board populated with a commercial inertial measurement unit (IMU) that can detect clinically useful metrics including pulse wave velocity at the aortic root. We use two spatially separated accelerometers to measure pulse wave propagation time with a standard deviation of 140 μs, which translates to an uncertainty of the pulse wave velocity of ±0.2 m/s. The sensor modules connect to a customized stent frame containing the necessary I2C conductors. Our data suggest that a fully instrumented TAVR paradigm is feasible using this frame design and modular sensor approach.
Design and Implementation of a Balloon Catheter Pressure Testing System
Authors: Tucker Aaron , Retherford Breanne , Rothweiler Paul , Selim Ahmed , Erdman Art
Published: August 2020

Medical device companies that aim to sell catheters with pressure sensing elements need a way to test their systems during the design phase. An example of one of these products is an Intra-aortic Balloon Pump (IABP) which provides mechanical pumping assistance to a patient experiencing cardiogenic shock.

To test these devices, companies will place the assembly in controlled pressure chamber to examine the response to pressure changes. However, commercially available systems are cost prohibitive.

To solve this problem, a custom, low-cost, pneumatic catheter test chamber was designed and built to provide a benchtop platform for experimentation.

In order to control the chamber pressure, the electromechanical system utilizes feedback control and solenoid valves controlled by an Arduino microcontroller. Since pneumatic systems exhibit nonlinear behavior, a novel control method was used to implement proportional-integral control and simulate the pressure profile experienced in the human body.
Adherence of Upper Airway Stimulation in US and German Medical Centers: A Multicenter Meta-Analysis on Adhere Registry
Authors: Lei Jingxin , Lee Kent
Published: August 2020

Upper airway stimulation (UAS) is shown to be effective with high adherence for patients with moderate to severe obstructive sleep apnea. However, the consistency of adherence among medical sites remains to be verified. This study examines the adherence to UAS among medical sites in an international multicenter registry. A statistically significant adherence decrease between 6-month and 12-month visit was found in the study cohort as well as in most sites. No significant heterogeneity was found among sites with either all patients or only patients who had adherence at both visits recorded. In addition, there is no enough evidence that region and experience of sites influences the adherence. This study indicates that UAS therapy adherence is consistent among sites, regardless of region and experience of sites.
A Pediatric Supracondylar Humerus Fracture Wire Navigation Simulator
Authors: Johnson Zane , Thomas Geb W. , Long Steven , Anderson Donald D.
Published: August 2020

Trainees in orthopedic surgery are required to receive dedicated laboratory-based surgical skills training in their first year of residency. Simulators are often used in this training. Our group previously developed a hip fracture wire navigation simulator to train and assess skill in placing a K-wire within a femur bone surrogate using synthetic fluoroscopic images to aid in navigation. In this paper, we describe design considerations and challenges in modifying the existing simulator to enable the training of multi-wire pinning of a pediatric supracondylar humerus fracture. The design involves changing the bone of interest from the adult femur to the pediatric humerus, while using the same platform technology. Considerations include ease of use, minimizing motion of the fixed bone, and minimizing materials used. The robustness of the bone mounting was tested by running an experiment using 3D scans and surface deviation analysis to test repeatability of bone placement and its resistance to rotational motion after being placed in the fixture. After the new design was shown to hold the bone rigidly, a pilot study of the new simulator was conducted to confirm that the surgeons and residents consider the simulator experience as being a valid representation of the actual surgical skill.
Single Versus Multiple Prototypes: Medical Device Design Practitioners’ Rationale for Varying Prototype Quantities to Engage Stakeholders During Front-End Design
Authors: Rodríguez-Calero Ilka , Coulentianos Marianna , Daly Shanna R. , Sienko Kathleen H.
Published: August 2020

Engaging stakeholders during medical device design processes, especially during front-end design activities, is a critical consideration for successful product design, which includes the safety and effectiveness of devices. The use of prototypes with stakeholders is encouraged by proponents of human-centered design, but guidelines for front-end stakeholder engagement with detailed descriptions of prototyping practices are lacking. One important question design practitioners must ask for each stakeholder engagement is how many prototypes to use. This study investigated reasons design practitioners chose to use one or more prototypes to engage stakeholders during front-end design activities within their design projects. Participants described using multiple prototypes, for example, to allow stakeholders to compare across different design alternatives, and to convey to stakeholders that multiple alternatives are being explored. Participants described using a single prototype, for instance, to probe for deep responses about a narrow topic and to refine a single concept through feedback. These results have the potential to inform design decisions and pedagogical approaches to prototyping use.
Laser Micromachining of Thin-Film Polyimide Microelectrode Arrays: Alternative Processes to Photolithography
Authors: Yeh Hsiang-Lan , Garich Jonathan V. , Akamine Ian R. , Blain-Christen Jennifer M. , Hara Seth A.
Published: August 2020

Thin-film microelectrode arrays have a wide variety of applications in research and medical devices. Conventionally, these arrays are fabricated through the use of photolithography, which can be problematic for innovative medical device fabrication due to long process times, inflexibility to design changes, and the reliance on potentially harmful chemicals. Here, we present the use of laser micromachining as an alternative to photolithography processes to fabricate thin-film polyimide microelectrode arrays. This fabrication method lends itself to an iterative design process as it can reduce fabrication steps and is attractive for medical devices since it can be used without harmful chemicals. Several process parameters were explored and the performance of the fabricated electrodes was compared to similar electrodes that were fabricated with conventional photolithography processes.
Can Real-Time Location System Replace Current Standard for Capture of Length of Stay?
Authors: Enayati Moein , Zanjirani Farahani Nasibeh , Nestler David , Heaton Heather , Pasupathy Kalyan
Published: August 2020

Background: Emergency Department Length of Stay (ED-LOS) is a crucial measurement for clinical and operational decisions and is used for regulatory reporting and research purposes. Accurate and standardized measurement of this duration improves the effectiveness of decisions and findings. Further, automated capture can eliminate dependence on human task-based data-entry.

Objective: Compare a real-time location system (RTLS)-based measure of LOS against the current standard of practice (EMR); examine factors associated with discrepancy in LOS.

Method: Estimation of LOS using the first and last RFID record in the RTL system, and statistical assessment of their similarity to the corresponding measurement from the EMR.

Result: Length of stay durations from the two methods have very similar distributions, with a slight shift.

Conclusion: RTLS provides an efficient and standardized means to measure LOS.
Light Weight Rigid OCS in Elevated Section of Delhi MRTS
Authors: Pande Om Hari , Tewari Ashok , Kumar Sanjeev
Published: August 2020

Delhi Metro is the first Metro in the world to provide 25 kV AC Rigid Overhead Conductor System (ROCS) in underground Tunnel. Most of the metros worldwide runs on 1500 V DC. The Elevated section of Delhi Metro is also provided with 25 kV AC Flexible OHE systems. The system is designed in accordance with EN-50119, 50122.

MRTS system plays an important role in functioning of the city transport. In the national capital of India, the Delhi Metro has become lifeline of Delhi since it’s inauguration in December 2002. Even occasional disruption of services, not only creates inconvenience & chaos between commuters but also invites severe criticism from public & media.

A number of failures in flexible OHE have caused disruption of metro services in the past few years. In elevated & at grade sections, DMRC is using conventional 25 kV AC flexible OHE where contact wire is suspended from a stranded messenger wire. Detailed analysis of the failure incidents indicated that catenaries’ parting and strands breakages due to short circuit contribute a significant portion i.e. 49% of total flexible OHE failures, While ROCS in underground stations is giving almost trouble-free services. Exploration of the possibilities of adopting Rigid OCS in elevated section shall help in reducing the breakdowns in 25kV traction as this will eliminate the component (i.e. Messenger wire) which is responsible for major failure. Also, mechanical properties of ROCS during electrical faults are far superior to that of flexible OHE.
The Next Generation of Train Control for Canadian Heavy Haul Systems
Authors: Thurston David F.
Published: August 2020

Heavy Haul Rail Transport in Canada has not advanced as in other countries. This gives these railways a chance to leap over intermediate technology in Train Control, Asset Management and levels of RAMS not offered in previous designs. Train Control is part of a System of Systems (SoS) that provides the basis of safety for operations, while allowing other non-vital systems to be implemented cheaper and faster than systems currently being modified to perform these tasks. This paper performs several tasks. First, it will update the reader on work being performed under the auspices of the Railway Association of Canada for Enhanced Train Control, and then it will describe how Train Control will interact with other systems to provide the overall functionality for safe train movement. Finally, the base requirements for a Train Control System meeting the requirements for Enhanced Train Control will be described.

The initial concepts and designs will be presented to show how the requirements will be met. In addition, the pilot project that is underway for proof of concept and operational readiness will be detailed. Test cases will be illustrated and portions of an Operational Concept, Requirements Analysis and Form Fit ad Function (F3) specifications will be documented. All of this will be the stepping stone for other systems to lead in advanced functionality and operation on Canadian Railways of the future.
Wireless Communication for High-Speed Passenger Rail Services: A Study on the Design and Evaluation of a Unified Architecture
Authors: Banerjee Subharthi , Hempel Michael , Ghasemzadeh Pejman , Sharif Hamid , Omar Tarek
Published: August 2020

High-speed trains, though prevalent in Europe and Asia, are not yet a reality in the US. But interest and industry engagement are growing, especially around commercial hubs close to commuter homes for alleviating commute times. With support from the Federal Railroad Administration in the United States, the authors are exploring the design requirements, challenges, and technology capabilities for wireless communication between passenger cars, on-board systems and with trackside infrastructure, all using next-generation radio access technologies. Key aspects of this work focus on interoperability, modularity of the architecture to facilitate a future-proof design, high-performance operations for passenger services and ultra-low latency capabilities for train control operations.

This paper presents the theoretical studies and computer simulations of the proposed network architectures, as well as the results of an LTE/5G field test framework using an OpenAir-Interface (OAI)-based software-defined radio (SDR) approach. Through various test scenarios the OAI LTE/5G implementation is first evaluated in a lab environment and through field tests. These tests provide ground-truth data that can be leveraged to refine the computer simulation model for evaluating large-scale environments with high fidelity and high accuracy. Of particular focus in this evaluation are performance aspects related to delay, handover, bit error rate, frequency offset and achievable uplink/downlink throughput.
Probabilistic Fatigue Crack Growth of Detail Fractures in Different Rail Steels
Authors: Jeong David Y. , Woelke Pawel
Published: August 2020

The most common rail defect encountered in continuously welded rail is known as the detail fracture. The U.S. Department of Transportation, Federal Railroad Administration has sponsored and managed research over the past several decades to understand the structural integrity of rail in general, and the fatigue crack growth behavior of detail fractures in particular. Control of rail integrity and defect growth is conducted via periodic rail tests (i.e. inspections) to ensure that rail defects do not become large enough to cause rail failure. Moreover, federal regulations have been codified to establish a maximum interval between rail inspections based on the results of government-sponsored research.

Over the past several decades, however, rail manufacturing has evolved and improved, particularly the head-hardening process to improve wear resistance. Propagation life of railroad rail was examined in previous research using fatigue crack growth data for non-head-hardened rail. Recently Thornton-Tomasetti conducted research, sponsored by FRA, to examine the fatigue crack growth behavior of modern rail steels (i.e. railroad rails with head-hardening). The initial results of the more recent research effort were reported in the 2019 Joint Rail Conference.

In this paper, fatigue crack growth rate data generated for head-hardened rail are used to examine the fatigue crack growth life of detail fractures under nominal revenue service conditions. Moreover, this paper applies a probabilistic approach to estimate rail life to account for the inherent variability or scatter typically observed in fatigue crack growth rate data. Regression methods are employed to derive the parameters for the Walker crack growth rate equation, which are subsequently treated as correlated, multivariate, and normally distributed random variables. Data from four different rail steels are used in the regression analyses, which are referred to as: Advanced Head Hardened (AHH), Head Hardened (HH), Standard Strength (SS), and Colorado Fuel and Iron (CF&I). Monte Carlo simulations of fatigue growth of detail fractures are carried out to estimate fatigue life distributions for each of the different rails. The results from these four rail steels are compared to those based on the previous research for non-head-hardened rails. Implications of these comparisons on determining rail testing intervals are discussed.
Behaviour of Metro Coach on Newly Built Track in Kolkata
Authors: Danawe Hrishikesh Gajanan , Singh Sudhir Kumar , Racherla Vikranth , R. Singh Sanjay , Prasad Arun
Published: August 2020

This paper presents the behaviour of a new metro coach on a newly built track in Kolkata, India. Oscillation trials were conducted using LVDT sensors at different locations to monitor primary and secondary springs compression. Multibody dynamics model is built with actual parameters of coach and track in SIMPACK. The behaviour of the vehicle for given track with elevation and curvature changes has been studied. Vehicle performance has been evaluated based on safety, running behaviour and track fatigue mentioned in UIC 518. Results of primary and secondary spring compressions obtained from field trials and multibody dynamics model have been compared. Coach lateral and vertical acceleration, bogie lateral acceleration, static load at rail wheel contact and derailment coefficient obtained from the multibody dynamics model are discussed. Obtained results were within permission values. Scope of this paper lies in studying the vehicle performance in connection to safety and running behaviour of newly introduced metro in Kolkata.
A Literature Review on Railroad Tank Car Thermal Protection Systems
Authors: Bian Zheyong , Carchi Nathalie , Liu Xiang
Published: August 2020

Railroad tank car transportation is the most efficient way to transport large amounts of hazardous material. More than 2 million tank-car loads of hazardous materials (hazmat) are transported annually by rail in the United States. Recently, the boom in the production of petroleum crude oil and natural gases from shale has dramatically increased the rail transport volume of flammable energy resources. However, accidents do occur, and the transportation of flammable hazardous material can result in disastrous consequences. The fire can heat up a tank car, rapidly increasing the inside pressure and causing the tank car to either rupture or explode. Railroad companies are developing or seeking advanced thermal protection systems to prevent tank car explosion or prolong the burst time to win a sufficient rescue time. It is of great importance to understand the existing thermal protection systems used in hazmat tank cars and to identify key priorities that the government and industry consider for improving tank car thermal protection performance, providing guidance for future thermal protection material development. Thus, this paper reviews the literature on the effects and analysis of different tank car thermal protection systems, identifying the effectiveness of different thermal protection components, properties of thermal protection materials, and testing methodologies.

Different combinations of insulators and jackets are tested in order to observe the effects of the fire on the tank car. The tank car is tested while carrying hazardous material like liquefied petroleum gas, propane, and ethylene oxide, etc. This investigation analyzes the differences of thermal protection systems in prolonging the life span of a tank car engulfed in flames.

A tank car can use either material like fiberglass, ceramic fiber blankets, perlite powder, or urethane foam to better insulate and thermally protect the tank car. An insulator is shown to prolong the life span of a tank car since bare tank cars tend to heat up rapidly when exposed to flames. The thermal protection system of a tank car is built of insulators, jackets, and supporting material for the insulator. The supporting material and jacket combination with the insulator also prevent the tank car from heating up rapidly.

There are two primary testing methods, pool fire, and torch fire. Each type of fire has different outcomes and limits in which the tank car can withstand. When testing the heating of a tank car, thermocouples were placed throughout a tank car and recorded to check what areas were heated the most during the experiment. Some factors that had been accounted for in the previous studies were the wind speed and the direction of the wind, which affected the overall experiment, mostly torch fire experiments.
Field Testing Plan for Positive Train Control Enforcement in Passenger Terminals
Authors: Zhang Zhipeng , Liu Xiang , Holt Keith
Published: August 2020

In the United States, a train moving onto a terminating track at a passenger terminal relies on the train engineer’s operation. Currently, there are no mechanisms installed at the U.S. passenger terminals that are able to automatically stop a train before reaching the end of the track if an engineer fails to do so. The engineer’s actions determine whether the train will safely stop before the end of the terminating track. Thus, incapacitated or inattentive engineer operation would result in end-of-track collisions, such as the New Jersey Transit train accident at Hoboken Terminal in 2016. Currently, PTC enforcement is not required in passenger terminals. In an ongoing project tasked by the Federal Railroad Administration, we study the cost-effectiveness and operational impact of possible PTC enforcement to prevent end-of-track collisions. Specifically, a Concept of Operations (ConOps) was developed to outline the proposed plans to implement two of the most widely used PTC types, namely the Advanced Civil Speed Enforcement System (ACSES) and Interoperable Electronic Train Management System (I-ETMS). This paper describes in-field testing of the ConOps in ACSES-type terminal.

In the planned field test, a train equipped with one locomotive and at least one passenger coach would be tested on platform tracks in a selected passenger terminal. These are three major testing components, which are test equipment, test track, and recorded information for each test sequence. Firstly, in terms of equipment, a traffic cone will be placed on the track to simulate a bumping post. In ACSES system, two sets of transponders are programmed to require a positive stop within a specified distance and mounted to the cross ties at specified positions. Secondly, a yard track will be used to test the feasibility of this exercise at the beginning. Upon successfully completing the test multiple times, a series of tests will also be made on the studied platform track. Thirdly, each test run should record the distance from the head end of the test train and the traffic cone for each test run. In addition, ACSES system should also record the information on the ACSES display as it passes the first and second transponder set, respectively. Overall, the field tests presented in this paper, along with previous work in benefit-cost analysis and operational impact assessment, can contribute to an assessment of the proposed PTC implementation at stub-end terminals in the United States in order to effectively and efficiently prevent end-of-track collisions.
Characterize Rail Crack Pattern Through Image Analysis
Authors: DeVine Ryan , Qian Yu , Wang Yi , Wang Shaofeng , Rizos Dimitris
Published: August 2020

Railway provides more than 40% of the freight ton-miles moved in the U.S. each year, surpassing all other modes of transportation. In addition to moving more tonnage farther than other modes, trains have better fuel efficiency than trucks and airplanes due to the low friction between the wheels and the rails. With traffic accumulation, rails will degrade which may lead to different types of defects, including but not limited to spalling, separation, crack, and corrugation. Rail head fissures or surface crack is often associated with rolling fatigue and must be addressed through grinding or other maintenance activities to restore the smooth-running surface. This ensures the riding conforms to operational safety requirements. The growth pattern of rail surface cracks has not been thoroughly understood or well-quantified yet due to the difficulties of rail crack inspection and insufficient data. This paper presents a study that uses image analysis techniques to detect and quantify cracks in images of rail segments that were taken in the field. Various crack detection techniques were tested and compared with visual inspection, including thresholding, edge detection, and bottom-hat filtering. The crack length, direction, and curvature were also quantified with each approach. Cracks were found to grow not perpendicular to the rail head, but with a certain angle from the vertical direction and relatively evenly distributed along the rail. The bottom-hat filtering technique was found to be the best in terms of accuracy among the methods tested in this study. The results from the study fill the gap of the literature by quantitatively characterizing the rail crack growth pattern and helping to identify possible approaches for future autonomous crack detection.
Radiation Transport Simulation Results Assessment Through Comparison With Reduced Complexity Analytic and Computational Models (LA-UR-20-22342)
Authors: Remedes Tyler J. , Ramsey Scott D. , Schmidt Joseph H. , Baciak James
Published: August 2020

In the past when faced with solving a non-tractable problem, scientists would make tremendous efforts to simplify these problems while preserving fundamental physics. Solutions to the simplified models provided insight into the original problem. Today, however, the affordability of high-performance computing has inverted the process for analyzing complex problems. In this paradigm, results from detailed computational scenarios can be better assessed by “building down” the complex model through simple models rooted in the fundamental or essential phenomenology.

This work demonstrates how the analysis of the neutron flux spatial distribution behavior within a simulated Holtec International HI-STORM 100 spent fuel cask is enhanced through reduced complexity analytic and computational modeling. This process involves identifying features in the neutron flux spatial distribution and determining the cause of each using reduced complexity computational and/or analytic model. Ultimately, confidence in the accuracy of the original simulation result is gained through this analysis process.
LiF by atomic layer deposition—Made easy
Authors: Kvalvik Julie N. , Kvamme Kristian B. , Almaas Kjetil , Ruud Amund , Sønsteby Henrik H. , Nilsen Ola
Published: August 2020

Lithium fluoride (LiF) is an integral part of UV optics. Recently, it has also gained attention for its role in the solid-electrolyte interphase on the anode of lithium-ion batteries. Atomic layer deposition (ALD) is the preferred tool for synthesizing conformal and pin-hole free LiF thin films, especially on high aspect ratio structures. Present routes to deposit LiF by ALD are based on HF or HF-pyridine as the fluorine source, requiring strict safety precautions. Other routes involve TiF4 or WF6, resulting in inclusions of Ti or W impurities in the resulting films. Herein, we present a new route to deposit LiF by ALD, using lithium tert-butoxide (LiOtBu) and NH4F as precursors. The process yields uniform films over a broad temperature range (150–300 °C), with a growth per cycle of 50.9 pm/cycle (225 °C). The films are free from any nitrogen contamination from the NH4F precursor. This process provides a facile route for high purity LiF thin films with the use of less harmful precursor chemistry.
A Novel Two-Component System, XygS/XygR, Positively Regulates Xyloglucan Degradation, Import, and Catabolism in Ruminiclostridium cellulolyticum
Authors: Kampik Clara , Denis Yann , Pagès Sandrine , Perret Stéphanie , Tardif Chantal , Fierobe Henri-Pierre , de Philip Pascale
Published: August 2020

Ruminiclostridium cellulolyticum
is a Gram-positive, mesophilic, anaerobic, cellulolytic, and hemicellulolytic bacterium. The last property qualifies this species as a model species for the study of hemicellulose degradation, import of degradation products, and overall regulation of these phenomena. In this study, we focus on the regulation of xyloglucan dextrin import and intracellular degradation and show that the two components of the two-component regulation system XygSR are essential for growth on xyloglucan and that the response regulator XygR regulates the transcription of genes involved in the extracellular degradation of the polysaccharide, the import of degradation products, and their intracellular degradation.
Genome-Wide Mutagenesis Identifies Factors Involved in Enterococcus faecalis Vaginal Adherence and Persistence
Authors: Alhajjar Norhan , Chatterjee Anushila , Spencer Brady L. , Burcham Lindsey R. , Willett Julia L. E. , Dunny Gary M. , Duerkop Breck A. , Doran Kelly S.
Published: August 2020

Enterococcus faecalis
is a Gram-positive commensal bacterium native to the gastrointestinal tract and an opportunistic pathogen of increasing clinical concern.
E. faecalis
also colonizes the female reproductive tract, and reports suggest vaginal colonization increases following antibiotic treatment or in patients with aerobic vaginitis. Currently, little is known about specific factors that promote
E. faecalis
vaginal colonization and subsequent infection.
NOD2/c-Jun NH
2
-Terminal Kinase Triggers Mycoplasma ovipneumoniae-Induced Macrophage Autophagy
Authors: Luo Haixia , Wu Xixi , Xu Zhaokun , Hao Xiujing , Wang Yongyu , Li Min
Published: August 2020

M. ovipneumoniae
, which lacks a cell wall, causes infectious pleuropneumonia in goats and sheep. In the present study, we focused on the interaction between NOD and
M. ovipneumoniae
, as well as its association with autophagy. We showed for the first time that NOD2 was activated by
M. ovipneumoniae
even when peptidoglycans were not present. We also observed that both NOD2 and JNK pathway activation promoted
M. ovipneumoniae
-induced autophagy.
Diagnosis of occupational asthma from serial measurements of forced expiratory volume in 1 s (FEV1) using the Area Between Curves (ABC) score from the Oasys plotter
Authors: Parkes Edward D , Moore Vicky C , Walters Gareth I , Burge Peter Sherwood
Published: August 2020

Objectives

To identify the changes in serial 2-hourly forced expiratory volume in 1 s (FEV1) measurements required to identify occupational asthma (OA) using the Oasys Area Between Curves (ABC) score.

Methods

The ABC score from 2-hourly measurements of FEV1was compared between workers with confirmed OA and asthmatics without occupational exposure to identify the optimum separation using receiver operator characteristic (ROC) analysis. Separate analyses were made for plots using clock time and time from waking to allow for use in shift workers. Minimum record criteria were ≥6 readings per day, >4 day shifts and >4 rest days (or >9 days for controls).

Results

A retrospective analysis identified 22 workers with OA and 30 control asthmatics whose records reached the quality standards. Median FEV1diurnal variation was 20.3% (IQR 16.1–32.6) for OA and 19.5% (IQR 14.5–26.1) for asthmatic controls. ROC curve analysis identified that a difference of 0.056 L/hour gave a ROC score of 0.821 for clock time and 0.768 for time from waking with a sensitivity of 73% and a specificity of 93% for the diagnosis of OA.

Conclusions

The diagnosis of OA requires objective confirmation. Unsupervised serial FEV1measurements are more difficult to obtain reliably than measurements of peak expiratory flow, which are likely to remain the standard for general use. A FEV1ABC score >0.056 L/hour provides a valid cut-off for those who wish to use FEV1rather than peak expiratory flow.
Epidemiology of SARS-CoV-2 antibodies among firefighters/paramedics of a US fire department: a cross-sectional study
Authors: Caban-Martinez Alberto J , Schaefer-Solle Natasha , Santiago Katerina , Louzado-Feliciano Paola , Brotons Angel , Gonzalez Marco , Issenberg S. Barry , Kobetz Erin
Published: August 2020

Objectives

We estimate the point seroprevalence of SARS-CoV-2 antibodies in the frontline firefighter/paramedic workforce of a South Florida fire department located in the epicentre of a State outbreak.

Methods

A cross-sectional study design was used to estimate the point seroprevalence of SARS-CoV-2 antibodies using a rapid immunoglobulin (Ig)M-IgG combined point-of-care lateral flow immunoassay among frontline firefighters/paramedics collected over a 2-day period, 16–17 April 2020. Fire department personnel were emailed a survey link assessing COVID-19 symptoms and work exposures the day prior to the scheduled drive-through antibody testing at a designated fire station. Off-duty and on-duty firefighter/paramedic personnel drove through the fire station/training facility in their personal vehicles or on-duty engine/rescue trucks for SARS-CoV-2 antibody testing.

Results

Among the 203 firefighters/paramedics that make up the fire department workforce, 18 firefighters/paramedics (8.9%) tested positive for SARS-CoV-2 antibodies, of which 8 firefighters/paramedics (3.9%) were IgG positive only, 8 (3.9%) were IgM positive only and 2 (0.1%) were IgG/IgM positive. The positive predictive value (PPV) of the serological test is estimated to be 33.2% and the negative predictive value is 99.3%. The average number of COVID-19 case contacts (ie, within 6 feet of an infected person (laboratory-confirmed or probable COVID-19 patient) for ≥15 min) experienced by firefighters/paramedics was higher for those with positive serology compared with those with negative (13.3 cases vs 7.31 cases; p=0.022). None of the antibody positive firefighters/paramedics reported receipt of the annual influenza vaccine compared with firefighters/paramedics who tested negative for SARS-CoV-2 antibodies (0.0% vs 21.0%; p=0.027).

Conclusion

Rapid SARS-CoV-2 IgM-IgG antibody testing documented early-stage and late-stage infection in a firefighter workforce providing insight to a broader medical surveillance project on return to work for firefighters/paramedics. Given the relatively low PPV of the serological test used in this study back in April 2020, caution should be used in interpreting test results.
Volcanic reconstruction and geochemistry of the Powderhouse formation in the Paleoproterozoic VMS-hosting Chisel sequence, Snow Lake, Manitoba, Canada
Authors: Friesen V.C. , DeWolfe Y.M. , Gibson H.L.
Published: August 2020

The Powderhouse formation of the Paleoproterozoic Snow Lake arc assemblage comprises the stratigraphic footwall to six volcanogenic massive sulfide (VMS) deposits at Snow Lake, Manitoba, Canada. It is interpreted to be a product of voluminous pyroclastic eruptions and concomitant subsidence followed by a period of relative volcanic quiescence that was dominated by suspension sedimentation, the reworking of previously deposited pyroclastic units by debris flows and bottom currents, and localized emplacement of rhyolite domes. The rhyolite domes are spatially associated with the Chisel, Chisel North, Lost, Ghost, Photo, and Lalor deposits. The Chisel, Lalor, and Lost members compose the Powderhouse formation and are subdivided into 13 lithologically distinct lithofacies, which allows, for the first time, correlation of stratigraphy between the South Chisel basin and Lalor areas, critical in predicting the location of largely stratiform VMS deposits. The Chisel and Lalor members contain lithofacies and bedforms that are characteristic of emplacement by subaqueous pyroclastic mass flows and concomitant subsidence. The Chisel member also contains coarse volcaniclastic breccias emplaced by mass debris flows derived from movement along fault scarps following early pyroclastic eruptions, and during continued subsidence. The Lost member consists of lithofacies deposited by mass flows generated from faults scraps during continued subsidence, but also contains lithofacies reworked by bottom currents, those deposited by suspension sedimentation, and, locally, coherent rhyolite. The Lost member represents a time stratigraphic interval, the “ore interval”, that marks contemporaneous rhyolite dome emplacement, VMS formation, and a hiatus in explosive volcanism.
Forcing and Calculi for Hybrid Logics
Authors: Găină Daniel
Published: August 2020

The definition of
institution
formalizes the intuitive notion of logic in a category-based setting. Similarly, the concept of
stratified institution
provides an abstract approach to Kripke semantics. This includes hybrid logics, a type of modal logics expressive enough to allow references to the nodes/states/worlds of the models regarded as relational structures, or multi-graphs. Applications of hybrid logics involve many areas of research, such as computational linguistics, transition systems, knowledge representation, artificial intelligence, biomedical informatics, semantic networks, and ontologies. The present contribution sets a unified foundation for developing formal verification methodologies to reason about Kripke structures by defining proof calculi for a multitude of hybrid logics in the framework of
stratified institutions
. To prove completeness, the article introduces a
forcing
technique for
stratified institutions with nominal and frame extraction
and studies a
forcing property
based on syntactic consistency. The proof calculus is shown to be complete and the significance of the general results is exhibited on a couple of benchmark examples of hybrid logical systems.
Atmospheric Corrosion Behavior of Arc Thermal Spray Zn-Al Coatings Using Accelerated Atmospheric Field Test for Ten-Year
Authors: NAKANO Atsushi
Published: August 2020

As a basic study on corrosion life of thermal spray coatings, accelerated field test with artificial seawater for 10-year were carried out for thermal spray Zn-30mass%Al coatings. By using artificial sea water, atmospheric field test accelerates corrosion due to chloride in comparison with a general atmosphere field test. Thermal sprayed specimens were prepared using an arc thermal spray method with compressed air on carbon steel subjected surface treatment. The formation of the oxide coating and the invasion of Cl and S to the inside layer were detected in 10-year of both the atmospheric field and the accelerated atmospheric field exposure tests, but the significant difference in the thickness of the thermal spray coating was not observed. In addition, for the accelerated atmospheric field test with spraying artificial seawater, thermal spray coating part remained satisfactorily, and it showed high corrosion resistance withstanding the 10-year atmospheric field test.
Electroforming In Space And Ground Telescopes
Authors: Giuseppe Valsecchi
Published: August 2020

In the last 25 years, electroforming process has been extensively optimized to produce grazing incidence optics for the X-ray space telescopes, enabling the renown observatories Beppo-SAX for the Italian Space Agency, SWIFT for NASA, XMM Newton for ESA, eROSITA for MPE. These optics are made of thin Nickel mirrors that are grown by electroforming process in an electrolytic bath on a Gold coated mandrel.Electroforming has also been adopted for production of large reflector panels for sub-millimeter radio telescope applications. Between 2006 and 2016, 3000 mirror panels for 25 antennas of the ALMA radio-telescope array of ESO and 1600 mirror panels for the 50-m diameter Large Millimeter Telescope (LMT) “Alfonso Serrano” of INAOE were designed, produced and tested.
Relationship between Oxidative Stress Biomarkers and Visual Field Progression in Patients with Primary Angle Closure Glaucoma
Authors: Li Shengjie , Shao Mingxi , Li Yingzhu , Li Xiaojuan , Wan Yani , Sun Xinghuai , Cao Wenjun
Published: August 2020

Purpose. To investigate the serum changes of oxidative stress markers and the relationship between these factors and visual field (VF) progression in patients with primary angle closure glaucoma (PACG). Methods. A case-control and a prospective cohort study. A total of 94 patients with PACG and 89 normal controls were enrolled. Furthermore, 94 PACG subjects were followed up for at least two years (once every six months). All participants were evaluated for serum levels of superoxide dismutase (SOD), total antioxidant status (TAS), hydrogen peroxide (H2O2), malondialdehyde (MDA), glutathione peroxidase, glutathione reductase, and detailed eye and systematic examination. Binary logistic regression analysis and Cox regression analysis were performed. Results. The serum levels of SOD and TAS in the PACG group were significantly lower than those in the control group (p<0.001). Meanwhile, PACG subjects had significantly higher levels of MDA and H2O2 than the normal control subjects (p<0.001). Serum levels of TAS (OR=0.773, 95%CI=0.349−0.714, p<0.001), SOD (OR=0.975, 95%CI=0.955−0.995, p<0.001), MDA (OR=1.155, 95%CI=1.080−1.235, p<0.001), and H2O2 (OR=1.216, 95%CI=1.142−1.295, p<0.001) were independent risk/protective factors for PACG. TAS levels (HR=0.041, 95%CI=0.008–0.218, p<0.001), SOD levels (HR=0.983, 95%CI=0.971–0.994, p=0.003), and MDA levels (HR=1.010, 95%CI=1.001–1.018, p=0.015) at baseline were associated with visual field progression. Kaplan–Meier curves reveal that patients with TAS<0.95/SOD<143/MDA>12 had a significantly higher percentage of PACG progression (p<0.05). Conclusions. Decreased levels of TAS and SOD as well as increased levels of MDA at baseline were associated with VF progression in patients with PACG. These findings suggest that oxidative stress was involved in the onset and development of PACG.
Chemical Composition of an Anthelmintic Fraction of Pleurotus eryngii against Eggs and Infective Larvae (L3) of Haemonchus contortus
Authors: Cruz-Arévalo Julio , Sánchez José E. , González-Cortázar Manases , Zamilpa Alejandro , Andrade-Gallegos Rene H. , Mendoza-de-Gives Pedro , Aguilar-Marcelino Liliana
Published: August 2020

This study was aimed at evaluating the in vitro effect of the edible mushroom (EM) Pleurotus eryngii against the eggs and larvae (L3) of Haemonchus contortus. The evaluation included acetone (AE) and hydroalcoholic (HA) extracts of the following strains: ECS‐1138, ECS‐1156, ECS‐1255, ECS‐1258, ECS‐1261, ECS‐1282, and ECS‐1292. The HA extract of the ECS‐1255 strain showed the highest effect on mortality rates of L3 (18.83%) at 20 μg/mL. After subjecting this HA extract to a normal phase chromatography column, five fractions were obtained; fraction F5 (100% MeOH) was the most effective against eggs, with hatching inhibition percentages of 88.77 and 91.87% at 20 and 40 mg/mL, respectively. Gas chromatography‐mass spectrometry (GC‐MS) subjected this fraction to an acetylation reaction to determine the content of the secondary metabolites. The GC‐MS analysis showed that the F5 fraction was composed of trehalose CAS: 6138‐23‐4, polyols (L‐iditol CAS: 488‐45‐9, galactitol CAS: 608‐66‐2, D‐mannitol CAS: 69‐65‐8, D‐glucitol CAS: 50‐70‐4, and myoinositol CAS: 87‐89‐8), adipic acid CAS: 124‐04‐9, stearic acid CAS: 57‐11‐4, squalene CAS: 111‐02‐4, and β‐sitosterol CAS: 83‐46‐5.