bluuebunny/crossref_metadata_2025 huggingface dataset:
Fracture and Deformation Behavior in Slow-Strain-Rate Tensile Testing of Cu–Ni Alloy With Internal Hydrogen
Authors: Wada Kentaro , Yamabe Junichiro , Ogawa Yuhei , Takakuwa Osamu , Iijima Takashi , Matsunaga Hisao
Published: November 2019

The effect of hydrogen on the deformation and fracture behavior in pure Cu, pure Ni and Cu–Ni alloy was studied via tensile tests of H-charged, smooth and circumferentially-notched specimens at room temperature (RT) and 77 K. Hydrogen-diffusion properties were determined by the desorption method. To obtain a uniform hydrogen concentration in the H-charged specimens, specimens were exposed to 100-MPa hydrogen gas at 543 K for 200 h, based on the determined hydrogen diffusivity. In tensile tests of smooth pure Ni and Cu–Ni alloy specimens at RT, common hydrogen effects were detected, namely, an increase in yield and flow stresses — a hardening effect; and a ductility loss that was accompanied by a change in fracture surface from ductile to brittle feature — an embrittling effect. With regard to the embrittling effect, the pure Ni and Cu–Ni alloy showed different fracture-surface morphologies at RT; the pure Ni showed an intergranular (IG) surface and the Cu–Ni alloy surface was flat. However, a number of IG cracks were detected beneath the fracture surfaces on the smooth Cu-Ni alloy. The tensile tests of the H-charged smooth specimens at 77 K yielded an IG surface for the pure Ni and a ductile fracture surface with dimples in the Cu–Ni alloy. In contrast, tensile tests of the H-charged, notched specimens at RT demonstrated clear IG fractures for the pure Ni and Cu–Ni alloy. These facts indicate that IG cracking was the first step in the embrittling process for the pure Ni and Cu–Ni alloy, and IG cracking was accompanied by a large plastic deformation that formed the flat surface (unclear IG surface) for the smooth Cu–Ni alloy. Considering that the HE of both pure Ni and Cu–Ni alloy was related to IG cracking, possible mechanisms were discussed and tensile tests performed at 77 K suggested two possibilities: (I) interaction between hydrogen-moving dislocation is more important in the HE process of the Cu-Ni alloy compared to the pure Ni; (II) hydrogen transportation towards grain boundaries are required to cause the IG fracture in the Cu-Ni alloy.
Limits of Allowable Static and Cyclic Loads on Lens Ring Gaskets
Authors: Maderbacher Hermann
Published: November 2019

Due to their relative simple handling and the high reliability, lens ring gaskets are widely used in high pressure connections. In addition, they are able to withstand large external forces without being damaged but at the same time they do not lose leak tightness even with very small contact forces. This ability to withstand high loads allows a lens ring gasket to be reused several times with minimal polishing after disassembling the flange connection.

However, this reusability has its end when the lens ring gasket is damaged or destroyed by static or cyclic overload. Static overload is mainly caused by too high bolt tightening force and leads to large scale plastic deformation. This damage can be easily avoided by choosing the correct bolt preload and proper flange alignment. A greater difficulty is the damage prediction by cyclic overload. This is caused by pressure fluctuations, excitations in the range of natural frequencies or other external cyclic loads. The effects of these mentioned loads on the service life of the lens ring gasket additionally depend on factors such as the stiffness of the individual components of the flange connection, the initial bolt preload or the materials used.

In the present work a method is presented which is able to predict the load limits of lens ring gaskets under static and cyclic loading. This method allows the consideration of different geometric influences of the individual components, of different materials and bolt preloads. From the static and cyclic forces on the flange connection, local stresses in the lens ring are calculated. This enables making a statement regarding plastic deformation due to bolt load and fatigue failure due to cyclic loads.
A Study on the Reuse of Xylan 1424 Studs
Authors: Ruffin Mark
Published: November 2019

While there are many factors that should be considered when determining if a stud can be reused, one of them is the nut factor. The study described in this paper set out to determine if the nut factor of a Xylan 1424 coated stud is significantly affected by the age of the coating and/or the cycles of tightening. A load cell was used to compare the nut factor: 1) of previously installed (used) studs to new studs, 2) of a new and used stud that were tightened more than once, and 3) associated with the first tightening pass to subsequent passes for a new stud. The results show that the age of the stud and the amount it has been tightened contribute to an increased nut factor for used Xylan 1424 studs.
Overview of Current Practice for Analysis and Design of Independent Spent Fuel Storage Installation Pads
Authors: Kwon Gunup , Ata Khaled
Published: November 2019

Nuclear power plant spent fuels are initially stored in the spent fuel pool. Then, the water cooled fuels are transferred in a concrete or steel cask and transported outside of the Fuel Handling Building (FHB) or the Reactor Building (RB) for long term on site storage. The spent fuel casks are typically stored on a slab-on-grade pad. The slab-on-grade pad is designed according to the U.S. Nuclear Regulatory Commission NUREG-1536 and NUREG-1567. The two Standard Review Plans provide guidance to the regulators for the review of cask storage system license application. The ISFSI pad analysis and design have to consider various loading conditions, such as earthquake and tornado loadings as well as normal operating loading conditions. Seismic analysis of the ISFSI pad requires considering interaction between the pad and the supporting soil. Various cask loading configurations on the pad also have to be considered. Due to the lack of specific guidelines, many ISFSI pad designs show overly conservative reinforcement. This study provides guidelines and procedure for the design of the ISFSI pad that are typically used in the nuclear industry. It is considered that the guidelines and practices described in this study help design engineers understand general guidance provided in the NRC Standard Review Plans.
Auxiliary Beam Stress Improved Laser Welding for Repair of Irradiated Light Water Reactor Components
Authors: Chen Jian , Tatman Jonathan , Feng Zhili , Miller Roger , Tang Wei , Gussev Maxim , Leonard Keith , Sutton Benjamin , Frederick Greg
Published: November 2019

The welding task focuses on development of advanced welding technologies for repair and maintenance of nuclear reactor structural components to safely and cost-effectively extend the service life of nuclear power reactors. This paper presents an integrated research and development effort by the Department of Energy Light Water Reactor Sustainability Program through the Oak Ridge National Laboratory (ORNL) and Electric Power Research Institute (EPRI) to develop a patent-pending technology, Auxiliary Beam Stress Improved Laser Welding Technique, that proactively manages the stresses during laser repair welding of highly irradiated reactor internals without helium induced cracking (HeIC). Finite element numerical simulations and in-situ temperature and strain experimental validation have been utilized to identify candidate welding conditions to achieve significant stress compression near the weld pool during cooling. Preliminary welding experiments were performed on irradiated stainless-steel plates (Type 304L). Post-weld characterization reveals that no macroscopic HeIC was observed.
Numerical Surrogate Model of a Coupled Tank-Piping System for Seismic Fragility Analysis With Synthetic Ground Motions
Authors: di Filippo Rocco , Abbiati Giuseppe , Sayginer Osman , Covi Patrick , Bursi Oreste S. , Paolacci Fabrizio
Published: November 2019

Seismic risk evaluation of coupled systems of industrial plants often needs the implementation of complex finite element models to consider their multicomponent nature. These models typically rely on significant computational resources. Moreover, the relationships between seismic action, system response and relevant damage levels are often characterized by a high level of nonlinearity, thus requiring a solid background of experimental data. Furthermore, fragility analyses depend on the adoption of a significant number of seismic waveforms generally not available when the analysis is site-specific. To propose a methodology able to manage these issues, we present a possible approach for a seismic reliability analysis of a coupled tank-piping system. The novelty of this approach lies in the adoption of artificial accelerograms, FE models and experimental hybrid simulations to evaluate a surrogate meta-model of our system. First, to obtain the necessary input for a stochastic ground motion model able to generate synthetic ground motions, a disaggregation analysis of the seismic hazard is performed. Hereafter, we reduce the space of parameters of the stochastic ground motion model by means of a global sensitivity analysis upon the seismic response of our system. Hence, we generate a large set of synthetic ground motions and select, among them, a few signals for experimental hybrid simulations. In detail, the hybrid simulator is composed by a numerical substructure to predict the sliding response of a steel tank, and a physical substructure made of a realistic piping network. Furthermore, we use these experimental results to calibrate a refined ANSYS FEM. More precisely, we focus on tensile hoop strains in elbow pipes as a leading cause for leakage, monitoring them with strain gauges. Thus, we present the procedure to evaluate a numerical Kriging meta-model of the coupled system based on both experimental and finite element model results. This model will be adopted in a future development to carry out a seismic fragility analysis.
Variables Affecting Nut Factors in Bolted Flange Connections
Authors: Aycock Justin B. , Wilson Jeffery , Bausman Anita
Published: November 2019

Bolted flange connections are heavily used within the chemical production/processing, transportation, marine, and power generation industries to contain processes while minimizing leaks. These leaks could cause unsafe working conditions, environmental hazards, and/or loss of product which, in turn, can cause fines or higher operating cost for plants. A way to deter this from happening is to correctly load the fasteners of the bolted flange connections to ensure the fasteners are properly stretched to apply an adequate contact stress to the gasket. Good understanding of how bolted flanged connections are optimally loaded limits leakage. When applying load via controlled torque to a fastener, the torsional energy applied is translated into a perpendicular force acting on the nut’s face and threads that is mirrored on the other side of the fastener thus inducing the clamping force on the connection. To determine the clamping force generated from the applied torque, a typical torque equation is applied using an empirically derived composite friction term called the nut factor. The nut factor is a dimensionless constant that includes all of the friction effects in the torque-clamping force relationship. The friction occurs between the surfaces of bolt and nut threads and the faces of the nut and flange or washer. The higher the friction, the higher the nut factor resulting in a higher fastener torque to achieve the same clamping force load. This study looked at several variables that can cause changes in assembly nut factor magnitude including bolt grade, bolt load, lubrication, washer presence, and bolt diameter.
Direct-Current Electric Potential (D-C EP) Technique Validation Through an Experimental and Computational Study on Pipe With Surface Crack
Authors: Hioe Y. , Kalyanam S. , Wilkowski G. , Brust F. W. , Punch E.
Published: November 2019

The direct-current electric potential (d-c EP) technique (also known as Electrical Potential Drop, EPD) was developed by researchers in the 1960s and applied to cracked geometries. In this investigation, measurement of the d-c EP signature from a circumferential surface-crack profile in a pipe was attempted to characterize the flaw shape with higher resolution using state-of-the-art digital equipment. A part-circular profile of crack was inserted using an EDM technique in a small diameter (4-inch diameter Schedule 160) TP304 (Type304) stainless steel pipe. Experimentally, different magnitudes of electric-current were applied to obtain the d-c EP across the length of the crack (from the shallowest to the deepest point). Finite Element Analysis (FEA) was performed to calculate the variation of the d-c EP across the length of the crack. A sensitivity study was done for various distances between the d-c EP probe locations near the crack. A comparison of the d-c EP values obtained from the part-circular crack front and a semi elliptical crack FEA (more realistically seen/assumed in service crack cases and used in the ASME Section XI calculations) were made. The study also investigated the variation of the d-c EP for various crack depths through the thickness for the applied constant amplitude direct-current. The sensitivity on d-c EP probe location distance from the surface flaw and d-c EP probe location along the length of the surface flaw (from deepest or center of the surface flaw to the shallowest point or corner of the surface flaw) were investigated. The scatter in the acquired d-c EP data across the two sides of the crack was investigated and accuracy of crack depth characterization was characterized in detail. This was done to investigate the limits of d-c EP calibration curves used for crack growth predictions.

The d-c EP calibration curves are useful in determining the crack growth that occurs without destructively opening the specimen and also measuring the in-situ crack depth measurements real time during a pipe or other surface flawed component/fitting experiments.
Computations of Single and Multiphase Flows Using a Lattice Boltzmann Solver
Authors: Akhtar M. Wasy , Love Holley C.
Published: November 2019

There is considerable interest in high fidelity simulation of both single phase incompressible flows and multiphase flows. Most commonly applied numerical methods include finite difference, finite volume, finite element and spectral methods. All of these methods attempt to capture the flow details by solving the Navier–Stokes equations. Challenges of solving the Navier–Stokes single phase incompressible flows include the non-locality of the pressure gradient, non-linearity of the advection term and handling the pressure-velocity coupling. Multiphase flow computations pose additional challenges, such as property and flow variable discontinuities at the interface, whose location and orientation is not known a priori. Further, capturing/tracking of the multiphase interface requires solution of an additional advection equation. Recently, the lattice Boltzmann method has been applied to compute fluid dynamics simulations both for single and multiphase configurations; it is considered a modern CFD approach with improved accuracy and performance. Specifically, we employ a multiple-relaxation time (MRT) technique for the collision term on a D3Q27 lattice. The multiphase interface is captured using the phase-field approach of Allen-Cahn. Test cases include lid driven cavity, vortex shedding for a double backward facing step, Rayleigh Taylor instability, Enright’s deformation test and rising bubble in an infinite domain. These test cases validate different aspects of the single and multiphase model, so that the results can be interpreted with confidence that the underlying computational framework is sufficiently accurate.
Scaling of SN Curves for Varying ‘Initiation’ Crack Definitions From Striation Counted Environmental Fatigue Specimens: A 250 Micron Austenitic Stainless Steel SN Curve and Associated Fen Factors
Authors: Batten Joseph , Currie Chris , Mann Jonathan , Wright Keith
Published: November 2019

Future code development to adopt a risk-informed design methodology will require improved accuracy of fatigue initiation predictions. The ability to account for through wall strain gradients in plant components, particularly over the first 3 mm of wall thickness is one area where conservatism can be reduced. This is due to extant design fatigue curves being derived from strain controlled membrane loading tests where the 25% load drop definition for end of test equates to approximately a 3 mm crack.

Being able to define initiation fatigue curves for much shorter crack depths would enable fatigue crack growth methods to then predict the additional cycles, taking into consideration the strain gradient, required before the defined end of life crack size is reached.

The R5 procedure provides a method to adjust an existing Stress-Life (SN) curve representing an initiation crack depth, to a smaller depth. This method was developed for materials at higher temperature and for a CO2 cooling environment, thus its validity was uncertain for application to a Pressurised Water Reactor (PWR) plant.

This paper details the development of best estimate and design basis SN curves and environmental fatigue enhancement factors (Fen) for crack initiation to a depth of 250 μm.

It is concluded that the general methodology in R5 was found, through this work, to adequately describe fatigue initiation lives for stainless steel in a PWR environment when augmented with a crack size dependent Fen equation and with modified coefficients determined through regression.

The resulting method is similar to R5 in that an SN curve can be derived for any crack size, however the current data set only provides validation down to a crack size of 250 μm, as striations at shorter depths were not visible with existing methods.
Friction Stir Welding and Preliminary Characterization of Irradiated 304 Stainless Steel
Authors: Tang Wei , Gussev Maxim , Feng Zhili , Gibson Brian , Miller Roger , Chen Jian , Clark Scarlett , Leonard Keith , Tatman Jon , Sutton Ben , Frederick Greg
Published: November 2019

The mitigation of helium induced cracking in the heat affected zone (HAZ), a transition metallurgical zone between the weld zone and base metal, during repair welding is a great challenge in nuclear industry. Successful traditional fusion welding repairs are limited to metals with a maximum of a couple of atomic parts per million (appm) helium, and structural materials helium levels in operating nuclear power plants are generally exceed a couple of appm after years of operations. Therefore, fusion welding is very limited in nuclear power plants structural materials repairing. Friction stir welding (FSW) is a solid-state joining technology that reduces the drivers (temperature and tensile residual stress) for helium-induced cracking. This paper will detail initial procedural development of FSW weld trials on irradiated 304L stainless steel (304L SS) coupons utilizing a unique welding facility located at one of Oak Ridge National Laboratory’s hot cell facilities. The successful early results of FSW of an irradiated 304L SS coupon containing high helium are discussed. Helium induced cracking was not observed by scanning electron microscopy in the friction stir weld zone and the metallurgical zones between the weld zone and base metal, i.e. thermal mechanical affected zone (TMAZ) and HAZ. Characterization of the weld, TMAZ and HAZ regions are detailed in this paper.
Numerical Investigation of Pressure Fluctuations and Vibrations for Upward Two-Phase Flow in a Pipe
Authors: Meire Alexander , De Moerloose Laurent , Degroote Joris
Published: November 2019

Two-phase flows are encountered in a wide range of technological and natural situations. In the last decade, advances in the available computing power have enabled to solve the underlying equations with computational fluid dynamics (CFD) using multi-phase models for the interaction between the different phases. In this study, a volume of fluid (VOF) solver in OpenFOAM is used to investigate the pressure profile in a co-current upward pipe flow of air and water. It is hypothesized that pressure drop events are caused by local buildup of the slower liquid, whereas conservation of volume flow rate forces the dense liquid to accelerate. The calculated pressure gradients are larger than the corresponding experimental data. It is shown that this mismatch might be caused by the evaluation of the momentum balance based on mixture properties; the mixture density increases the effective liquid obstruction and the corresponding pressure drop. Finally, the effect of these pressure fluctuations on the pipe’s vibration is studied using a one-dimensional independent rings structural model.
Fracture Mechanics Based Asset Management Approach in SCC Environments
Authors: Segletes David , Tipple Christopher , Peters Daniel
Published: November 2019

The operation of autoclave vessels at elevated temperature and pressure is common across a variety of industries. Many of the older operating vessels were fabricated from multiple forgings by welding. Austenitic stainless steels are the material of choice for many of these vessels, and precautions to prevent sensitization in the weld heat affected zone may not have been implemented during construction, which can increase susceptibility to environmental cracking conditions. Recently a vessel developed a through wall leak during the operating cycle. Three complimentary vessels at the same facility were inspected resulting in one additional vessel not returning to service and two with similar flaws. A multi-disciplinary approach was used to evaluate the failure, perform a fitness for service determination, and nondestructive examinations to monitor the flaw growth and validate the fitness for service inputs. The overall approach is discussed.
Modeling and Simulations of Deteriorated Turbulent Heat Transfer in Wall Heated Cylindrical Tube
Authors: Vegendla Prasad , Hu Rui
Published: November 2019

The paper discusses the modeling and simulations of Deteriorated Turbulent Heat Transfer (DTHT) for a wall-heated fluid flows, which can be observed in gas-cooled nuclear power reactors during Pressurized Conduction Cooldown (PCC) event due to loss of force circulation flow. The DTHT regime is defined as the deterioration of normal turbulent heat transport due to increase of acceleration and buoyancy forces. The Computational Fluid Dynamics (CFD) tools such as Nek5000 and STAR-CCM+ can help to analyze the DTHT phenomena in reactors for efficient thermal-fluid designs.

3D CFD non-isothermal modeling and simulations were performed in a wall-heated circular tube. The simulation results were verified with two different CFD tools, Nek5000 and STAR-CCM+, and validated with an experimental data. The predicted bulk temperatures were identical in both CFD tools, as expected. Good agreement between simulated results and measured data were obtained for wall temperatures along the tube axis using Nek5000. In STAR-CCM+, the under-predicted wall temperatures were mainly due to higher turbulence in the wall region. In STAR-CCM+, the predicted DTHT was over 48% at outlet when compared to inlet heat transfer values.
Analytic Solutions As a Tool for Verification and Validation of a Multiphysics Model
Authors: Tregillis I. L. , Koskelo Aaron
Published: November 2019

Computational physicists are commonly faced with the task of resolving discrepancies between the predictions of a complex, integrated multi-physics numerical simulation and corresponding experimental datasets. Such efforts commonly require a slow iterative procedure. However, a different approach is available in cases where the multi-physics system of interest admits closed-form analytic solutions. In this situation, the ambiguity is conveniently broken into separate consideration of theory-simulation comparisons (issues of verification) and theory-data comparisons (issues of validation).

We demonstrate this methodology via application to the specific example of a fluid-instability based ejecta source model (“RMI+SSVD”) under development at Los Alamos National Laboratory and implemented in FLAG, a Los Alamos continuum mechanics code. The formalism is conducted in the forward sense (i.e., from source to measurement) and enables us to compute, purely analytically, piezoelectric ejecta mass measurements for a specific class of explosively driven metal coupon experiments. We incorporate published measurement uncertainties on relevant experimental parameters to estimate a time-dependent uncertainty on these analytic predictions. This motivates the introduction of a “compatibility score” metric, our primary tool for quantitative analysis of the RMI+SSVD model.
Monitoring subwavelength grating structures for vertical-cavity surface-emitting laser applications by spectroscopic ellipsometry
Authors: Balogh Emeric , Basa Peter , Suto Attila , Powell Benjamin , Bölcskei-Molnár Anna , Biró Szilvia
Published: November 2019

GaAs based vertical cavity surface emitting lasers (VCSELs) have one of the fastest growing markets due to their numerous applications in imaging technology, optical sensors, and interconnects. Stable, single-mode operation of these laser diodes is often achieved by forming subwavelength structures on the surface of the GaAs semiconductor. Quick and preferably noncontact inspection of the formed nanostructures is desired during the fabrication process. Nanostructure characterization by spectral ellipsometry-based metrologies has become an indispensable tool in the semiconductor industry. An advanced method of ellipsometry is the application of Mueller-matrix ellipsometry, which enables the characterization of structure details difficult to measure or not reachable by using standard ellipsometry measurements. In this paper, the authors present the results of nanostructure characterization by model-based dimension metrology using spectral ellipsometry and Mueller-matrix spectral ellipsometry of line gratings formed on GaAs substrates during the process of VCSEL fabrication.
Adiposity and Slow Stepping Rate Are Related to Under-Estimating Steps per Day in African American Women
Authors: Tyo Brian , Spataro-Kearns Rebecca , Bassett David R.
Published: November 2019

Purpose: The purpose of this study was twofold: (1) to determine if the Digi-Walker SW-200 (SW-200), New Lifestyles NL-2000 (NL-2000), and Omron HJ-303 (HJ-303) yield similar daily step counts compared to the StepWatch-3; and (2) to determine if pedometer error is influenced by adiposity and/or stepping rate in African American women. Methods: 60 participants (28.0 ± 9.8 y) wore the devices for three weekdays. ANOVAs were performed to determine if body mass index (BMI) and device were related to steps per day, and to determine if BMI and device were related to error. Stepwise linear regressions were performed to determine which variables contributed to pedometer error. Results: StepWatch-3 counted significantly more steps than all other devices within each BMI category (p < .01). The NL-2000 had significantly less error in the normal (−13.4%) and overweight (−14.9%) groups compared to the SW-200 (−26.2% and −33.3%) and HJ-303 (−32.5% ad −31.5%) (p < .05). The SW-200 had significantly more error in the obese group (−50.7%) compared to the NL-2000 (−17.1%) and HJ-303 (−26.0%) (p < .05). NL-2000 error was not related to any variables while the SW-200 error was related to waist circumference (WC) and the HJ-303 error was related to percentage of slow steps. Conclusion: In African American women adiposity is more strongly related to more pedometer error in a device using a spring-levered mechanism (SW-200). Accumulating steps at a slow rate is related to more pedometer error when using a device with a step filter (HJ-303).
High Agreement Between an Ultrasensitive Clostridioides difficile Toxin Assay and a C. difficile Laboratory Algorithm Utilizing GDH-and-Toxin Enzyme Immunoassays and Cytotoxin Testing
Authors: Landry Marie L. , Topal Jeffrey E. , Estis Joel , Katzenbach Phoebe , Nolan Niamh , Sandlund Johanna
Published: November 2019

The Singulex Clarity C. diff toxins A/B (Clarity) assay is an automated, ultrasensitive immunoassay for the detection of
Clostridioides difficile
toxins in stool. In this study, the performance of the Clarity assay was compared to that of a multistep algorithm using an enzyme immunoassay (EIA) for detection of glutamate dehydrogenase (GDH) and toxins A and B arbitrated by a semiquantitative cell cytotoxicity neutralization assay (CCNA).
Human Papillomavirus E7 Oncoprotein Subverts Host Innate Immunity via SUV39H1-Mediated Epigenetic Silencing of Immune Sensor Genes
Authors: Lo Cigno Irene , Calati Federica , Borgogna Cinzia , Zevini Alessandra , Albertini Silvia , Martuscelli Licia , De Andrea Marco , Hiscott John , Landolfo Santo , Gariglio Marisa
Published: November 2019

High-risk HPVs are major viral human carcinogens responsible for approximately 5% of all human cancers. The growth of HPV-transformed cells depends on the ability of viral oncoproteins to manipulate a variety of cellular circuits, including those involved in innate immunity. Here, we show that one of these strategies relies on E7-mediated transcriptional activation of the chromatin repressor SUV39H1, which then promotes epigenetic silencing of RIG-I, cGAS, and STING genes, thereby shutting down interferon secretion in HPV-transformed cells. Pharmacological or genetic inhibition of SUV39H1 restored the innate response in HPV-transformed cells, mostly through activation of RIG-I signaling. We also show that IFN production upon transfection of poly(dA·dT) or the RIG-I agonist M8 predominantly occurs through RIG-I signaling. Altogether, the reversible nature of the modifications associated with E7-mediated SUV39H1 upregulation provides a rationale for the design of novel anticancer and antiviral therapies targeting these molecules.
Changing Molecular Epidemiology of Vibrio cholerae Outbreaks in Shanghai, China
Authors: Hu Dalong , Yin Zhiqiu , Yuan Chao , Yang Pan , Qian Chengqian , Wei Yi , Zhang Si , Wang Yuhui , Yuan Jian , Wang Meng , Reeves Peter R. , Tu Lihong , Chen Min , Huang Di , Liu Bin
Published: November 2019

V. cholerae
is the causative agent of cholera, a life-threatening disease characterized by severe, watery diarrhea. The 7th pandemic started in Indonesia in 1961 and spread globally, currently infecting 1.3 million to 4 million people annually. Here, we applied whole-genome sequencing to analyze a long-term collection of
V. cholerae
clinical strains to reveal the phylogenetic background and evolutionary dynamics of the 7th pandemic in Shanghai, which had undergone breathtakingly rapid development in the last half-century. All but one of the Shanghai 7th-pandemic strains fell into five “stages” that were dominant in Shanghai and appeared to be closely related to 7th-pandemic strains of South or Southeast Asia. Our findings extended the understanding of the dynamics of the evolution and transmission of the 7th-pandemic clones in East Asia and the relationship between social changes and cholera epidemiology.
Kommerell’s diverticulum: rare cause of unilateral vocal cord palsy
Authors: Kumar Pawan , Singh Anuradha , Hanumanthappa Chandrashekhara Sheragaru
Published: November 2019

Kommerell’s diverticulum is a relatively rare congenital aortic arch anomaly. A 56-year-old man presented with complaint of gradually progressive hoarseness of voice since 6 months. Clinical examination revealed no evidence of palpable neck mass or cervical lymphadenopathy. Indirect laryngoscopy showed right vocal cord in median position and was immobile during phonation with normal left vocal cord. This was followed by contrast-enhanced CT (CECT) of the neck and upper chest for further evaluation. CT scan showed features of right vocal cord palsy. CECT also showed right-sided aortic arch with aberrant origin of the left subclavian artery. Aneurysmal dilatation of the aortic arch was noted at the take off of aberrant left subclavian artery suggesting Kommerell’s diverticulum. Therefore, diagnosis of right vocal cord palsy due to compression of the right recurrent laryngeal nerve (RLN) by Kommerell’s diverticulum was kept. Left RLN palsy did not occur in this case because the left RLN likely courses around the normal segment of the aortic arch just proximal to the origin of the left subclavian artery. As the patient was mildly symptomatic, he was kept on conservative treatment with close follow-up. The present case report highlights importance of the inclusionn of the superior mediastinum on CT scan in case of suspected vocal cord palsy to exclude vascular causes of RLN paralysis.
Improvement of perioperative care of the elderly patient (PeriAge): protocol of a controlled interventional feasibility study
Authors: Olotu Cynthia , Lebherz Lisa , Härter Martin , Mende Anna , Plümer Lili , Goetz Alwin E , Zöllner Christian , Kriston Levente , Kiefmann Rainer
Published: November 2019

Introduction

Geriatric patients have a pronounced risk to suffer from postoperative complications. While effective risk-specific perioperative measures have been studied in controlled experimental settings, they are rarely found in routine healthcare. This study aims (1) to implement a multicomponent preoperative and intraoperative intervention, and investigate its feasibility, and (2) exploratorily assess the effectiveness of the intervention in routine healthcare.

Methods and analysis

Feasibility and exploratory effectiveness of the intervention will be investigated in a monocentric, prospective, non-randomised, controlled trial. The intervention includes systematic information for patients and family about measures to prevent postoperative complications; preoperative screening for frailty, malnutrition, strength and mobility with nutrient supplementation and physical exercise (prehabilitation) as needed. Further components focus on potentially inadequate medication, patient blood-management and carbohydrate loading prior to surgery, retainment of orientation aids in the operating room and a geriatric anaesthesia concept. Data will successively be collected from control, implementation and intervention groups. Patients aged 65+ with impending surgery will be included. A sample size of 240, n=80 per group, is planned. Assessments will take place at inclusion and 2, 30 and 180 days after surgery. Mixed-methods analyses will be performed. Exploratory effectiveness will be assessed using mixed segmented regressions. The primary endpoint is functional status. Secondary endpoints include cognitive performance, health-related quality of life, length of inpatient stay and occurrence of postoperative complications. Feasibility will be assessed through semi-structured interviews with staff and patients and quantitative analyses of the data quality, focussing on practicability, acceptance, adoption and fidelity to protocol.

Ethics and dissemination

The study will be carried out in accordance with the Helsinki Declaration and to principles of good scientific practice. The Ethics Committee of the Medical Association Hamburg, Germany, approved the protocol (study ID: PV5596). Results will be disseminated in scientific journals and healthcare conferences.

Trial registration number

ClinicalTrials.gov Identifier:NCT03325413.
Defining the information needs of lung cancer screening participants: a qualitative study
Authors: Ruparel Mamta , Quaife Samantha , Baldwin David , Waller Jo , Janes Samuel
Published: November 2019

Introduction

Lung cancer screening (LCS) by low-dose CT has been shown to improve mortality, but individuals must consider the potential benefits and harms before making an informed decision about taking part. Shared decision-making is required for LCS in USA, though screening-eligible individuals’ specific views of these harms, and their preferences for accessing this information, are not well described.

Methods

In this qualitative study, we aimed to explore knowledge and perceptions around lung cancer and LCS with a focus on harms. We carried out seven focus groups with screening-eligible individuals, which were divided into current versus former smokers and lower versus higher educational backgrounds; and 16 interviews with health professionals including general practitioners, respiratory physicians, lung cancer nurse specialists and public health consultants. Interviews and focus groups were audio-recorded and transcribed. Data were coded inductively and analysed using the framework method.

Results

Fatalistic views about lung cancer as an incurable disease dominated, particularly among current smokers, and participants were often unaware of curative treatment options. Despite this, beliefs that screening is sensible and worthwhile were expressed. Generally participants felt they had the ‘right’ to an informed decision, though some cautioned against information overload. The potential harms of LCS were poorly understood, particularly overdiagnosis and radiation exposure, but participants were unlikely to be deterred by them. Strong concerns about false-negative results were expressed, while false-positive results and indeterminate nodules were also reported as concerning.

Conclusions

These findings demonstrate the need for LCS information materials to highlight information on the benefits of early detection and options for curative treatment, while accurately presenting the possible harms. Information needs are likely to vary between individuals and we recommend simple information materials to be made available to all individuals considering participating in LCS, with signposting to more detailed information for those who require it.
Longevity of pulmonary rehabilitation benefit for chronic obstructive pulmonary disease—health care utilisation in the subsequent 2 years
Authors: Walsh James R , Pegg Jane , Yerkovich Stephanie T , Morris Norman , McKeough Zoe J , Comans Tracy , Paratz Jenny D , Chambers Daniel C
Published: November 2019

Background

The primary aim was to determine the healthcare utilisation benefits including respiratory-related hospital admissions, hospital admission days and emergency department presentations in the 0–12 and 12–24 months postpulmonary rehabilitation compared with the 12 months preprogramme.

Methods

An observational, data-linkage design of 11 standardised pulmonary rehabilitation programmes were used. All programmes were 8 weeks in duration with two supervised exercise sessions per week and were required to use the national pulmonary rehabilitation recommendations with regard to programme organisation, exercise training guidelines and multidisciplinary education. For each participant with chronic obstructive pulmonary disease (COPD), healthcare utilisation data were collected for the 12 months preprogramme and 24 months postprogramme.

Results

426 participants (231 males, FEV149.3 (19.6) % predicted) were studied. The number of respiratory admissions/participant/year decreased from 0.7 (1.1) in the 12 months preprogramme to 0.5 (1.9) in the 12 months postprogramme, p=0.083; but increased in the 12–24 months postprogramme to 1.0 (2.3), p<0.001. The hospital days/participant/year improved from 4.0 (7.8) days in the 12 months preprogramme to 2.5 (8.5) days in the 12 months postprogramme, p<0.001; but increased in the 12–24 months postprogramme to 6.1 (16.6) days, p=0.004. The emergency department presentations/participant/year improved from 1.15 (1.75) in the 12 months preprogramme to 0.9 (1.8) in the 12 months postprogramme, p=0.003; but increased in the 12–24 months postprogramme to 2.0 (3.3), p<0.001.

Conclusion

Pulmonary rehabilitation significantly improves hospital days and emergency department presentations in the first 12 months postprogramme. Healthcare utilisation benefits in the second 12 months are less clear.
The impact of delayed transfers of care on emergency departments: common sense arguments, evidence and confounding
Authors: Keogh Brad , Monks Thomas
Published: November 2019

Objectives

There have been claims that Delayed Transfers of Care (DTOCs) of inpatients to home or a less acute setting are related to Emergency Department (ED) crowding. In particular DTOCs were associated with breaches of the UK 4-hour waiting time target in a previously published analysis. However, the analysis has major limitations by not adjusting for the longitudinal trend of the data. The aim of this work is to investigate whether the proposition that DTOCs impact the 4-hour target requires further research.

Method

Estimation of an association between two or more variables that are measured over time requires specialised statistical methods. In this study, we performed two separate analyses. First, we created two sets of artificial data with no correlation. We then added an upward trend over time and again assessed for correlation. Second, we reproduced the simple linear regression of the original study using NHS England open data of English trusts between 2010 and 2016, assessing correlation of numbers of DTOCs and ED breaches of the 4-hour target. We then reanalysed the same data using standard time series methods to remove the trend before estimating an association.

Results

After introducing upward trends into the uncorrelated artificial data the correlation between the two data sets increased (R2=0.00 to 0.51 respectively). We found strong evidence of longitudinal trends within the NHS data of ED breaches and DTOCs. After removal of the trends the R2reduced from 0.50 to 0.01.

Conclusion

Our reanalysis found weak correlation between numbers of DTOCs and ED 4-hour target breaches. Our study doesnotindicate that there is no relationship between 4-hour target and DTOCs, it highlights that statistically robust evidence for this relationship does not currently exist. Further work is required to understand the relationship between breaches of the 4-hour target and numbers of DTOCs.
Building the evidence base for waterpipe regulation and policy
Authors: Maziak Wasim , Sharma Eva
Published: November 2019

Waterpipe (hookah, shisha, narghileh) smoking is emerging as an epidemic, particularly among young people in the USA and globally. Unlike cigarettes, waterpipe smoking involves several components (eg, tobacco, charcoal, device and venues) and is characterised by unique smoking patterns that expose smokers to significant amounts of nicotine and other toxic substances. With the rising prevalence of use among young people and continuing misperceptions about waterpipe’s harmful nature, a better understanding of health risks associated with waterpipe smoking is warranted. In response to waterpipe’s rising trends, a Deeming Rule that extended the US Food and Drug Administration’s (FDA) regulatory authority to all tobacco products was issued in 2016. This rule includes waterpipe tobacco, components and parts. This development created the need for evidence to guide the FDA into best evidence-based strategies to limit waterpipe’s spread among young people and harm to public health. This special issue presents some of the studies that were funded under the ‘Chemistry, Toxicology, and Addiction Research on Waterpipe Tobacco’ programme to inform promising regulatory action on waterpipe products. In this preamble, we briefly summarise findings from these studies and discusses their policy and regulatory implications for different waterpipe products and components.
Assessment of residual slash coverage using UAVs and implications for aspen regeneration
Authors: Sealey Landon L. , Van Rees Ken C.J.
Published: November 2019

Proper redistribution of residual slash following harvesting is crucial for ensuring successful regeneration and continued health in trembling aspen (Populus tremuloides) forests. As traditional methods of measuring residual slash are a strenuous and tedious process, the objective of this study was to develop a new, faster, and more detailed method to assess residual slash distribution for entire harvested blocks. This study also aimed to assess the influence residual slash coverage had on the success of aspen regeneration 1 year after winter harvesting. Using high-resolution UAV imagery and maximum likelihood supervised image classification, residual slash was differentiated from the underlying forest floor. Overall, classification accuracy ranged between 85% and 96% with the highest accuracy occurring when aerial imagery was collected at the beginning of the second spring following winter harvesting. Slash distribution was quite consistent across harvested blocks, with 92% of harvested blocks experiencing <33% coverage. There was no relationship between the level of aspen regeneration following 1 year of growth and percentage slash coverage up to 60%. No vegetation plots occurred in areas with >60% slash coverage; therefore, it is unknown whether aspen regeneration will be affected in areas with higher slash coverage.
Development of a Hardware Circuit for Real-Time Acquisition of Brain Activity Using NI myDAQ
Authors: Chanu Oinam Robita , Kalpana R. , Soorya B. , Santhosh R. , Karthik Raj V.
Published: November 2019

Electroencephalography (EEG) is the recording of electrical activity of the brain. The 10–20 system is the standard electrode location method used to acquire EEG data, which uses 21 electrodes to record the electrical activity of the brain. Patient preparation and correct electrode placement are important to obtain reliable outputs. The current 10–20 system consumes greater time for patient preparation and also causes discomfort due to a higher number of electrodes being used or wearing an uncomfortable cap. This paper focuses on reducing the number of electrodes, thus reducing patient discomfort as well as preparation time. Advancement in the field of hardware and software processing has led to the utilization of brain waves for communication between human and the computer. This work deals with EEG-based Brain–Machine Interface (BMI) intended for designing a portable single-channel EEG signal acquisition system. EEG signal was acquired using the data acquisition module [National Instruments (NI) myDAQ] and the signal was viewed in the NI Laboratory Virtual Instrument Engineering Workbench (LabVIEW) environment. It was observed that the peak-to-peak amplitude of alpha, beta and theta waves changes in accordance with the activity the subjects performed. Thus, the developed instrument was tested on 10 different subjects to acquire the alpha, beta and theta waves by performing different activities. From the results, it can be concluded that the developed system can be used for studying a person’s brain waves (alpha, beta and theta) based on the activity performed by the subject with a limited number of electrodes.
Adaptive isogeometric boundary element methods with local smoothness control
Authors: Gantner Gregor , Praetorius Dirk , Schimanko Stefan
Published: November 2019

In the frame of isogeometric analysis, we consider a Galerkin boundary element discretization of the hyper-singular integral equation associated with the 2D Laplacian. We propose and analyze an adaptive algorithm which locally refines the boundary partition and, moreover, steers the smoothness of the NURBS ansatz functions across elements. In particular and unlike prior work, the algorithm can increase and decrease the local smoothness properties and hence exploits the full potential of isogeometric analysis. We prove that the new adaptive strategy leads to linear convergence with optimal algebraic rates. Numerical experiments confirm the theoretical results. A short appendix comments on analogous results for the weakly-singular integral equation.