bluuebunny/crossref_metadata_2025 huggingface dataset:
Electron Beam Welds in 316L Part 1: Weld Production, Residual Stress Measurements and Predictions
Authors: Horne Graeme , Moffat Andrew
Published: November 2022

There is enthusiasm for new civil nuclear plants in the UK to adopt power beam welding technologies, which could offer several advantages over conventional techniques. In particular, reduction in the time taken to produce and inspect a weld, and thus the cost of manufacturing components. However, a blocker to the adoption of these technologies is a shortage of accepted methodologies for demonstrating the integrity of these joints, which forms part of the requirements of the generic design assessment within the UK regulatory environment.

Residual stresses can contribute towards crack driving force and thus should be accounted for when assessing the integrity of a component or its tolerance to damage. Whilst bounding residual stress fields are often used, it is often desirable to have more realistic estimations that capture the through-wall residual stress distribution, which also allows them to be decomposed into membrane, bending and self-equilibrated components to aid stress classification.

Material-specific weld residual stress profiles already exist, for example Level 3 profiles in the UK’s R6 procedure. However, they are for arc welding techniques. This work seeks to provide a framework for the generation of weld residual stress profiles for power beam welds and is split over two papers:

1. Weld Production, Residual Stress Measurements and Predictions;

2. A Methodology and Example for Parameterised Residual Stress Profiles.

In this paper an experimentally-validated programme of weld modelling is presented to be used as an input to the framework for producing parametric through-thickness weld residual stress profiles presented in the second paper.
An Experimental and Analytical Study on the Development of Extrapolation Method for the Creep-Fatigue Life of Alloy 617 to Low Strain Ranges and Long Hold Times at 950°C
Authors: Hou Peijun , Sham Ting-Leung , Wang Yanli
Published: November 2022

Creep-fatigue is the most severe damage mode for high temperate components under cyclic loading. Experimentally, standard creep-fatigue testing is mostly performed at strain ranges of 0.3% and above. There is a major data gap in creep-fatigue failure information for strain ranges at 0.3%, or lower, which are more prototypical for advanced reactor plant operations. To develop design curves for creep-fatigue evaluations, it will require a method for extrapolating the creep-fatigue cyclic lives to lower strain ranges and longer hold times. In this study, methods for creep-fatigue life prediction of Alloy 617 at lower strain ranges and longer hold times at 950°C were assessed. Two types of experimental data were generated to support the development of the creep-fatigue design curves at low strain ranges and long hold times. First, standard strain-controlled creep-fatigue testing using the concept of block-strain range was conducted to generate the information needed for extrapolating the creep-fatigue design curves to lower strain ranges and longer hold times. Second, creep-fatigue experiments with elastic follow-up were performed to failure to verify the proposed design curves. Based on this new testing approach and analysis method, a preliminary creep-fatigue design curve was developed for Alloy 617 at 950°C. This study shows the potential of generating a set of creep-fatigue design curves with different hold times within a reasonable amount of test times and testing effort at the low strain range region.
Electron Beam Welds in 316L Part 2: A Methodology and Example for Parameterised Residual Stress Profiles
Authors: Horne Graeme , Elliott Ben , Moffat Andrew
Published: November 2022

There is enthusiasm for new civil nuclear plants in the UK to adopt power beam welding technologies, which could offer several advantages over conventional techniques. In particular, reduction in the time taken to produce and inspect a weld, and thus the cost of manufacturing components. However, a blocker to the adoption of these technologies is a shortage of accepted methodologies for demonstrating the integrity of these joints, which forms part of the requirements of the generic design assessment within the UK regulatory environment.

Residual stresses can contribute towards crack driving force and thus should be accounted for when assessing the integrity of a component or its tolerance to damage. Whilst bounding residual stress fields are often used, it is often desirable to have more realistic estimations that capture the through-wall residual stress distribution, which also allows them to be decomposed into membrane, bending and self-equilibrated components to aid stress classification.

Material-specific weld residual stress profiles already exist, for example Level 3 profiles in the UK’s R6 procedure. However, they are for arc welding techniques. This work seeks to provide a framework for the generation of weld residual stress profiles for power beam welds and is split over two papers:

1. Weld Production, Residual Stress Measurements and Predictions;

2. A Methodology and Example for Parameterised Residual Stress Profiles.

In this paper, the second in this series, a framework is presented for producing parametric through-thickness weld residual stress profiles using the validated modelling from the first paper in the series.
A Viscoplastic Model for Alloy 800H for Use With the Section III, Division 5 Design by Inelastic Analysis Methods for Class A Components
Authors: Messner M. C.
Published: November 2022

Recently, the ASME approved a new non mandatory appendix to Section III, Division 5, Subsection HB, Subpart B of the ASME Boiler & Pressure Vessel Code providing guidance on the Division 5 design by inelastic analysis methods for Class A components. This appendix provides guidance on constructing and validating nonlinear constitutive models for use with the Code rules as well as approved material models the designer can use without additional validation. An eventual goal for the new appendix is to provide reference models for all the HBB Class A materials. This paper describes an inelastic constitutive model for Alloy 800H, suitable for use with the design by inelastic analysis methods. The model uses a unified viscoplastic form and a detailed kinematic hardening model to capture the key features of high temperature cyclic behavior in Alloy 800H. At lower temperatures the model switches to a rate independent reponse to better capture the available experimental data. The paper describes the model form, calibration database, and details how the model was calibrated and validated against experiment data. The goal for this model is to incorporate it into the ASME Code, via the newly approved appendix to Subsection HB, Subpart B, to continue to expand the range of prebuilt constitutive models available to designers.
Mechanical Properties and the Effect of Hydrogen on Base Metal and Welds of 9Cr-1Mo-V Steel
Authors: Zuazo Rodriguez Ian , Alberini Stefano , Bouillot Claude , Cornut Dany , Fusari Fausto
Published: November 2022

9Cr-1Mo-V steel or Grade 91 has been typically used up to now in thermal power plants operating at high temperatures, e.g. 600°C. In another potential application, such as refinery equipment like hydrocracker and hydrotreater reactors, the choice is still the 2¼Cr-1Mo-¼V. The main reason is that the average design temperature of hydrocracker and hydrotreater reactors, approximately 450°C, has not been increased in the last 20 years making the use of 2¼Cr-1Mo-¼V steel more suitable and cheaper in comparison to Grade 91.

However, some recent interest has been observed for its application in the petrochemical and chemical sector, including for new process technologies related to green economy market sectors. In these applications the influence of hydrogen could be detrimental for the steel and in the past, some investigations concluded positively on the use of Grade 91. In recent years, an improved control of the chemistry intended to improve creep properties has led to the industrial production of the SA-387 Grade 91 Type 2.

Therefore, due to a renewed interest and an improved chemistry, tests were planned and carried out with the aim of assessing the hydrogen effect on the Grade 91 Type 2. This was done using welded test samples covering both full plate butt joints and weld overlays using two stainless steels, 308L and 347. In the butt joints, the impact transition curves of the weld metal, heat affected zone and base materials were compared to those after a heat treatment under high hydrogen pressure. The resistance to hydrogen induced disbonding was evaluated on the weld overlays. Finally, the influence of step cooling treatment on impact toughness was also investigated for both base and weld metal.
Analysis to Relate Data From Radial Compression Tests on Helical Springs to Tensile Material Properties
Authors: Gagnon Andre , Metzger Donald
Published: November 2022

In CANDU nuclear reactors, pressure tubes reside within a calandria tube with separation maintained by helical springs installed in the annular space. Evaluation of material degradation due to the unique operating environment requires testing of ex-service spring material by compressing short spring segments by two diametrically opposed forces. The load vs. displacement results combined with the geometry allows for the stress-strain behavior to be derived. The test specimens are effectively unmodified from the as-received condition so accurate characterization of the geometry is required. Since the test response is mainly bending, error in the radial section dimension is augmented by powers of 2 and 3 when calculating bending stress and specimen stiffness respectively. Additional complications come from nonuniform loading of the coils due to end effects.

Detailed analysis that accounts for end effects is applied to the linear elastic portion of the load curve to accurately quantify the specimen dimensions. With geometry determined, the nonlinear portion of the tensile curve is adjusted to reproduce the entire load curve up to the failure point. Examples are presented to demonstrate how the load corresponding to the yield point and outer fiber stress at the failure point can be determined.
Rocking Response Analysis of Flat-Bottom Cylindrical Tanks Considering Rotational Inertia of Content Liquid
Authors: Yoshida Yuichi , Taniguchi Tomoyo , Nakashima Teruhiro
Published: November 2022

This paper proposes an analytical method for calculating rocking responses of unanchored tanks during seismic ground motion. Some researchers have proposed the analytical methods to calculate seismic responses of unanchored tanks without considering the rotational inertia of content liquid. In other words, most of method for a time-history analysis of tank rocking responses are assumed that an equilibrium equation in direction of rotation can be formulated as a static equilibrium equation in which the overturning moment and the restoring moment are equal. Even a model that considers rotational inertia of content liquid was proposed in the past, the definition of moment of inertia is ambiguous. On the other hand, there a study that derives moment of inertia from a physical background and alleges the importance of the moment of inertia in the tank rocking response.

In this study, an analytical method of a time history analysis of tank rocking motion considering the rotational inertia of content liquid is proposed. Furthermore, results of the proposed method are compared with results of the FEM dynamic analysis to validate the accuracy of the proposed method. Finally, comparisons with results of the conventional calculation method are also conducted.
Inverse Conduction Method for Complex Thermal Loading
Authors: Gilman Timothy
Published: November 2022

For U.S. nuclear power plants, transfer functions have typically been utilized in fatigue monitoring applications to characterize a pressure vessel or piping component’s local, inside fluid temperatures, which are the primary forcing functions for stress cycling and the accumulation of fatigue damage, crack nucleation, and crack growth. The transfer function approach involves using simplified, conservative thermal-hydraulic engineering principles to develop algorithms that calculate the local temperatures, using existing plant instruments, such as temperatures, flow rates, valve positions, etc.

With the increased ease of adding instrumentation using modern thermocouple and wireless data technology, numerous practical uses are available to plants now, such as:

• More accurately and easily characterizing local thermal loading of components for analysis or fatigue monitoring, including flaw tolerance methods.

• Determining the inside temperature loading in normally-stagnant branch lines subject to thermal cycling. Accurate knowledge of inside temperatures in these lines can potentially eliminate the need for costly, frequent inspections when a significant temperature range threshold is not exceeded [1] [2].

• Inside temperate loading, based on measured data, can also provide the basis for detailed evaluations in emergent situations when cracks or new loadings are discovered.

With thermocouple data, temperatures on the outside surface of components are measured, but inside surface temperatures are needed to compute accurate stresses. There are challenges with attempting to deterministically calculate inside temperatures, because of numerical instability issues caused by temperature fluctuations, measurement inaccuracies, or both. The problem becomes increasingly complex when multiple instruments are required to characterize the loading, such as with thermal stratification or with thermal cycling caused by in-leakage interacting with swirl flow at a branch nozzle.

Because of stability challenges and the multivariate nature of the problem, a robust, generalized solution for computing inside temperatures at multiple different thermal zones is nontrivial.

Drawing on previous work, this paper discusses the challenge along with a proposed solution.
Predicting Pressure Relief Valve Generated Acoustic Induced Pipe Wall Vibration
Authors: Swindell Rob , Izuchi Hisao , Karczub Denis , Eilers Daniel , Mann J. Adin
Published: November 2022

The calculation of acoustic induced vibration (AIV) for piping downstream of a valve is a critical step in predicting the damage from extreme levels of noise generated by pressure relief valves in flare systems. Three noise prediction schemes are considered for this purpose: International Electrotechnical Commission (IEC) 60534-8-3, the Carucci-Mueller (C-M) formulation for sound power, and an industry valve noise prediction methodology published in the 1980’s. The application of these prediction methods is reviewed utilizing data from a full-scale test system consisting of an NPS6x8 pressure relief valve flowing into a NPS12 tailpipe that is connected through a tee to an NPS20 header. The results show good correlation between the IEC-based predictions and measured internal sound pressure and pipe wall vibration in the AIV frequency region. The industry method provides useful predictions without requiring the level of detailed information needed for the IEC method, whilst the C-M sound power model has limitations when applied to discrete predictions of vibration and strain levels. Observations are also made regarding the relative importance of the FIV contribution to the overall dynamic stresses and associated fatigue life.
A Novel Method to Predict the Concentricity of Aero-Engine Rotor Considering the Assembly Process of Bolted Flange Joints
Authors: Zhu Linbo , Yang Yilong , Huang Hongwei , Bouzid Abdel-Hakim , Hong Jun
Published: November 2022

The concentricity of the aero-engine rotor is an important parameter to evaluate the quality of final assembly and directly affects the vibration characteristics, especially for high-speed rotation. The use of a bolted flange joint is the basic type of connection in aero-engine rotors. During the initial tightening of the bolts, large deformation usually occurs in the flange because its thickness is small. The deformation in the flange has a major impact on the concentricity and consequently the dynamic behavior of the aero-engine rotor. This paper proposes a novel stack-build assembly method to predict the concentricity of multi-stage rotors considering the deformation of the flange. The Small Displacement Torsor (SDT) method is employed to construct the mathematical model of part errors. The homogeneous coordinate transformation method is used to analyze the deviation propagation in the bolted flange joint of each stage part. A finite element (FE) model is built to obtain the deformation of the bolted flange joints by simulating the assembly process. The deformation of the flange is involved in the stack-build assembly model as an error matrix. Furthermore, the influence of the assembly process such as interference and preload, tightening sequence on the concentricity is investigated. The results show that bolted flange joints have a significant effect on concentricity, especially for the complex geometry at the flange interface. The developed approach is validated by experimental tests conducted on a multi-stage rotor. This study can provide guidance and enhance the dynamic performance of bolted joints for aero-engine rotors.
Determination of Irradiated Stainless Steel Properties and Its Effects on Reactor Vessel Internals
Authors: Kwak Dong-Hyeon , Sim Jae Min , Chang Yoon-Suk , Kong Byeong Seo , Jang Changheui
Published: November 2022

Reactor vessel internals (RVIs) consist of austenitic stainless steels (ASSs) which have excellent material properties. Meanwhile, the high radiation environment of a reactor can cause the degradation of components. Since changed material properties are important for long-term operation, experimental researches related to tensile and fracture properties had been conducted. However, it is limited to investigate these researches due to their high radioactivity and small quantity. Thus recent researches have been dedicated to small specimens such as nanoindentation and micropillar compression tests and so on with ion-irradiation. In this study, micropillar compression tests were carried out for virgin and irradiated 304 ASSs to obtain microscopic mechanical behaviors. The trial sets of finite element (FE) analyses were performed to derive dislocation density based material constitutive equations for austenite phase by comparing with test results. Subsequently, representative volume elements analyses with periodic boundary conditions were adopted to estimate overall tensile stress-strain curves as well as 0.2% offset yield strengths (YSs) under the virgin and irradiated states. Finally, the effect of irradiated properties on typical RVIs were investigated. As typical results, optimized material parameters related to dislocation density based formulations were revealed, and microscopic stress-strain curves were reasonably comparable with test results. The estimated YS values were compared with the experimental results and corresponded within 9.09%. The overall deformation, stress and strain behaviors of typical RVIs were examined considering estimated properties, of which details and key findings will be discussed.
High Strength Heavy Wall HY-80 Flux Cored Arc Welding
Authors: Sun Dongmei , Johnstone Brent
Published: November 2022

HY-80 is a quenched and tempered high strength low alloy steel developed for use in naval applications, specifically for the submarine pressure hulls. Properly developed welding procedures and correct welding consumable selection are important for obtaining quality welds for HY-80 welding, especially when metal thickness is 50 mm and over.

Welding procedure qualification on 50 mm thick high strength HY-80 steel was performed using the mechanized flux cored arc welding (FCAW) process. A series of procedure qualification test panels were fabricated. Non-destructive examinations (NDE) and mechanical testing of the qualification panels were performed in accordance with the requirements of the applicable MOD UK standards.

Through detailed analysis of the welding parameters, mechanical properties, microstructures and NDE results of the test panels, this paper provides insight into the effects of welding process variables on mechanical properties and weld quality of heavy wall HY-80 welding.
Metallurgical Characterization of a 114,000-Hour Service-Aged Forge 91-Pipe 91 Steel Header Weldment
Authors: Wang Yiyu , Zhang Wei , Wang Yanli , Feng Zhili , Siefert John , Bridges Alex , Kung Steven
Published: November 2022

In this work, multi-scale metallurgical characterizations with advanced microscopy techniques were conducted on an ex-service girth weld between a SA-182 forge 91 (F91) steel reducer to a SA335 pipe 91 (P91) steel header after 141,000 hours (16 years) service at a coal-red power plant between 1991 and 2015. Multiple metallurgical factors, including compositions, inclusions, precipitates, and hardness, were analyzed in comparison for the F91 and P91 steels. The results not only gain an in-depth understanding of creep deformation mechanisms in 9Cr steel welds, but also provide baseline information for remaining lifetime assessments of those service-aged steam components. The results show highly nonuniform creep degradation and damages were observed on the F91 and P91 sides. Base metal and heat affected zone (HAZ) on the F91 steel side experienced a higher degree of microstructure degradation with lower hardness and a higher fraction of creep cavities. Softened zones with lower hardness values were identified in both HAZs of F91 side and P91 side. However, the most creep damaged zones (CDZ) with the highest number density of cavities are not the identified softened zones. In the CDZ, creep cavities are always associated with coarse precipitates (Laves phase, Z phase) and large inclusions (Al oxides, AlN, MnS). A higher fraction of inclusions, coarser precipitates, and larger grain size in F91 steel put itself and its HAZ more vulnerable to creep damages, especially the infamous Type IV cracking.
Seismic Assessment of Crossover Piping on a Sodium Cooled Fast Reactor With Three-Dimensional Isolation System
Authors: Watakabe Tomoyoshi , Okuda Takahiro , Okajima Satoshi
Published: November 2022

A three-dimensional seismic isolation system is planed for application to the conceptual design of a sodium-cooled fast reactor in Japan. The main steam crossover piping is laid between the nuclear building with the isolation system and the turbine building without the isolation system. A large displacement of the nuclear building with the isolation system is imposed on the crossover piping, which situation is a particular seismic issue because of the isolation system employment. Furthermore, because the SFR operates at elevated temperatures compared with light water reactors, the crossover steam piping design must comply with the design code for elevated temperature components. In this study, seismic evaluation using an example of a crossover piping layout was performed in accordance with the elevated temperature code of Japan Society of Mechanical Engineers. According to the evaluation results and the up to date technologies such as knowledge obtained from existing dynamic failure tests of piping components, an appropriate seismic evaluation method for the crossover piping was studied to realize the sodium-cooled fast reactor with a three-dimensional isolation system.
In Service Repair Challenges With Pyrolysis and Steam Methane Reformers High Temperature Metallurgy
Authors: Zhu Sophia , Dalal Mitul , Penso Jorge
Published: November 2022

The high temperature section of pyrolysis furnaces and steam methane reformers are exposed to conditions ranging from ambient temperature during shutdowns to temperatures near 1093°C (2000°F) when in service in the case of pyrolysis tubes. These conditions lead to variety of metallurgical transformation affecting material properties at different temperatures. The involved materials are exposed to internal and external environments leading to chemical and metallurgical reactions causing additional material property changes. Moreover, pressure boundary components also need to withstand other high temperature damage mechanisms including creep, stress-relaxation cracking, thermal fatigue, and thermal shock.

The paper reviews high temperature metallurgy and degradation mechanisms for both pyrolysis and steam methane reformer services. Several case histories are presented. For pyrolysis service, furnace coil failures due to thermal fatigue/thermal shock, quench nozzle failures and transfer line exchanger tube failures are covered. For steam methane reformer, several failures in furnace coil tubes, reducers, pigtails, and outlet headers are covered.

In order to select the suitable alloys for resistance of thermal shock and thermal fatigue, a research study has been carried out to rank the high temperature alloys’ resistance to thermal shock and thermal fatigue based on the test protocols which represent the extreme temperature conditions. General guidance on material selection, failure prevention and welding repairs are included.
Comparison Between Different Calculation Methods for Determining Bolting-Up Torque Moments
Authors: Mutz Alexander , Schaaf Manfred , Hufnagel Stefan
Published: November 2022

The ASME BPVC, Section III, Appendix XI [1] regulates the flange calculation for class 2 and 3 components in Suisse nuclear power plants, and it is also used for class 1 flanges.

The most common European Standard for the design of bolted flanged joints is EN 1591-1 [2], the required gasket characteristics for this calculation procedure are defined in EN 13555 [3]. These characteristics can be determined experimentally and they are not only used in EN 1591-1 but also in more realistic finite-element calculations.

Finite element calculations are carried out for a certain number of combinations of flange and gasket materials as well as bolt types in order to prove compliance with the integrity and tightness of the connections in the assembly and subsequent operational states, taking into account the tightening torques. A total of almost 400 different combinations of flange, bolt and gasket geometries and materials were examined. The focus is laid on flange types fabricated according to European standards which are generally thinner — looking at the wall thickness or flange ring in the same pressure range — than in the ASME world.

In this paper the bolting-up torque moments determined with the European standard EN 1591-1 for the flange connections, are assessed with twice elastic slope method, limit load and elastic-plastic stress analysis according to ASME BPVC, Section VIII, Div. 2. [4] Proof of acceptability of the nonlinear finite element-calculations are conducted according to ASME standard procedures like ASME SECTION III, Appendices EE and FF for the level D.
Regulatory Testing and 3D Scanning Methodology of the DPP-1 Type Shipping Container for NCT and HAC Tests
Authors: Martinez Oscar , Adeniyi Abiodun , Nogradi Paul , Van Hoy Blake
Published: November 2022

The safe transportation of radioactive material using appropriately designed and certified transportation packages is important for protecting the public and environment. In the United States, the US Department of Transportation (DOT) regulates all transportation of radioactive material with input from the US Nuclear Regulatory Commission. All packages that contain radioactive materials must be transported and regulated by the requirements set by the DOT Class 7 transportation of hazardous material. Federal regulations place strict administrative controls on the transport of radioactive materials. The two main goals for transporting radioactive materials are that (1) safety is primarily focused on the package because it is the first line of defense and (2) package integrity is directly related to the degree of the hazard of the radioactive material contents. The two-part goal ensures that the correct package is used. Type B packages are designed to transport radioactive materials with the highest level of radioactivity. Examples of material transported in Type B packaging include spent nuclear fuel, high-level radioactive waste, and high concentrations of other radioactive materials. The purpose of this test protocol was to determine the effects of structural and thermal testing on package performance in a Type B shipping package, Defense Program Package-1 (DPP-1).
Gold nanoparticle design for RNA compaction
Authors: Nash Jessica A. , Manning Matthew D. , Gulyuk Alexey V. , Kuznetsov Aleksey E. , Yingling Yaroslava G.
Published: November 2022

RNA-based therapeutics hold a great promise in treating a variety of diseases. However, double-stranded RNAs (dsRNAs) are inherently unstable, highly charged, and stiff macromolecules that require a delivery vehicle. Cationic ligand functionalized gold nanoparticles (AuNPs) are able to compact nucleic acids and assist in RNA delivery. Here, we use large-scale all-atom molecular dynamics simulations to show that correlations between ligand length, metal core size, and ligand excess free volume control the ability of nanoparticles to bend dsRNA far below its persistence length. The analysis of ammonium binding sites showed that longer ligands that bind deep within the major groove did not cause bending. By limiting ligand length and, thus, excess free volume, we have designed nanoparticles with controlled internal binding to RNA's major groove. NPs that are able to induce RNA bending cause a periodic variation in RNA's major groove width. Density functional theory studies on smaller models support large-scale simulations. Our results are expected to have significant implications in packaging of nucleic acids for their applications in nanotechnology and gene delivery.
Diffusion-assisted molecular beam epitaxy of CuCrO2 thin films
Authors: Rimal Gaurab , Mazza Alessandro R. , Brahlek Matthew , Oh Seongshik
Published: November 2022

Using molecular beam epitaxy (MBE) to grow multielemental oxides (MEOs) is generally challenging, partly due to difficulty in stoichiometry control. Occasionally, if one of the elements is volatile at the growth temperature, stoichiometry control can be greatly simplified using adsorption-controlled growth mode. Otherwise, stoichiometry control remains one of the main hurdles to achieving high-quality MEO film growths. Here, we report another kind of self-limited growth mode, dubbed diffusion-assisted epitaxy, in which excess species diffuses into the substrate and leads to the desired stoichiometry, in a manner similar to the conventional adsorption-controlled epitaxy. Specifically, we demonstrate that using diffusion-assisted epitaxy, high-quality epitaxial CuCrO2 films can be grown over a wide growth window without precise flux control using MBE.
Planar focusing lens for enhanced far-field ultrasonic imaging
Authors: Zhang Mengru , Chen Jian , Chen Mu , Fan Zheng
Published: November 2022

This paper presents a far-field enhanced-resolution underwater ultrasonic imaging on the basis of a single-slit structured planar focusing lens. The iterative angular spectrum approach was employed to optimize the planar focusing lens from a designated focal pattern, characterized by focal length and full width at half maxima. Numerical simulations and experimental investigations were conducted on different target objects. Compared to the conventional method, both results showed that the performance of far-field ultrasonic imaging was comprehensively enhanced with the proposed planar focusing lens, in terms of resolving capability, working distance, operational bandwidth, and robustness. The single-slit structured planar focusing lens is cost effective and easy to fabricate, which would greatly benefit ultrasonic imaging and drive new applications of ultrasound in various scenarios.
Single-cell multiomics identifies clinically relevant mesenchymal stem-like cells and key regulators for MPNST malignancy
Authors: Wu Lai Man Natalie , Zhang Feng , Rao Rohit , Adam Mike , Pollard Kai , Szabo Sara , Liu Xuezhao , Belcher Katie A. , Luo Zaili , Ogurek Sean , Reilly Colleen , Zhou Xin , Zhang Li , Rubin Joshua , Chang Long-sheng , Xin Mei , Yu Jiyang , Suva Mario , Pratilas Christine A. , Potter Steven , Lu Q. Richard
Published: November 2022

Malignant peripheral nerve sheath tumor (MPNST), a highly aggressive Schwann cell (SC)–derived soft tissue sarcoma, arises from benign neurofibroma (NF); however, the identity, heterogeneity and origins of tumor populations remain elusive. Nestin
+
cells have been implicated as tumor stem cells in MPNST; unexpectedly, single-cell profiling of human NF and MPNST and their animal models reveal a broad range of nestin-expressing SC lineage cells and dynamic acquisition of discrete cancer states during malignant transformation. We uncover a nestin-negative mesenchymal neural crest-like subpopulation as a previously unknown malignant stem-like state common to murine and human MPNSTs, which correlates with clinical severity. Integrative multiomics profiling further identifies unique regulatory networks and druggable targets against the malignant subpopulations in MPNST. Targeting key epithelial-mesenchymal transition and stemness regulators including ZEB1 and ALDH1A1 impedes MPNST growth. Together, our studies reveal the underlying principles of tumor cell-state evolution and their regulatory circuitries during NF-to-MPNST transformation, highlighting a hitherto unrecognized mesenchymal stem-like subpopulation in MPNST disease progression.
Recursive sequence generation in crows
Authors: Liao Diana A. , Brecht Katharina F. , Johnston Melissa , Nieder Andreas
Published: November 2022

Recursion, the process of embedding structures within similar structures, is often considered a foundation of symbolic competence and a uniquely human capability. To understand its evolution, we can study the recursive aptitudes of nonhuman animals. We adopted the behavioral protocol of a recent study demonstrating that humans and nonhuman primates grasp recursion. We presented sequences of bracket pair stimuli (e.g., [ ] and { }) to crows who were instructed to peck at training lists. They were then tested on their ability to transfer center-embedded structure to never-before-seen pairings of brackets. We reveal that crows have recursive capacities; they perform on par with children and even outperform macaques. The crows continued to produce recursive sequences after extending to longer and thus deeper embeddings. These results demonstrate that recursive capabilities are not limited to the primate genealogy and may have occurred separately from or before human symbolic competence in different animal taxa.
Taking the STING out
Authors: Kim Young , Pillai Asha
Published: November 2022

ABCC1 is an ATP-dependent cGAMP exporter responsible for negatively regulating STING signaling.
Redundancy in Citrate and
cis
-Aconitate Transport in
Pseudomonas aeruginosa
Authors: Underhill Simon A. M. , Cabeen Matthew T.
Published: November 2022

Pseudomonas aeruginosa
is a bacterium that infects hospitalized patients and is often highly resistant to antibiotic treatment. It preferentially uses small organic acids called tricarboxylates rather than sugars as a source of carbon for growth.
ATPase Activity of Bacillus subtilis RecA Affects the Dynamic Formation of RecA Filaments at DNA Double Strand Breaks
Authors: Hernández-Tamayo Rogelio , Steube Niklas , Heimerl Thomas , Hochberg Georg K. A. , Graumann Peter L.
Published: November 2022

Single-strand (ss) DNA binding ATPase RecA is the central recombinase in homologous recombination, and therefore essential for DNA repair pathways involving DNA strand exchange reactions. In several bacterial, RecA forms filamentous structures along the long axis of cells after induction of double strand breaks (DSBs) in the chromosome.
Exploring the Impacts of Full-Scale Distribution System Orthophosphate Corrosion Control Implementation on the Microbial Ecology of Hydrologically Connected Urban Streams
Authors: Spencer-Williams Isaiah , Balangoda Anusha , Dabundo Richard , Elliott Emily , Haig Sarah-Jane
Published: November 2022

Elevated lead levels in drinking water supplies are a public health risk. As such, it is imperative for cities to urgently address lead contamination from aging drinking water supplies by way of lead service line replacements and corrosion control methods.
Pyocyanin and 1-Hydroxyphenazine Promote Anaerobic Killing of Pseudomonas aeruginosa via Single-Electron Transfer with Ferrous Iron
Authors: Kang Jihee , Cho You-Hee , Lee Yunho
Published: November 2022

Pseudomonas aeruginosa
is an opportunistic human pathogen which infects patients with burns, immunocompromised individuals, and in particular, the mucus that accumulates on the surface of the lung in cystic fibrosis (CF) patients. Phenazines as redox-active small molecules have been reported as important compounds for the control of cellular functions and virulence as well as anaerobic survival via electron shuttles.
Industry strategies to market opioids to children and women in the USA: a content analysis of internal industry documents from 1999 to 2017 released in State of Oklahoma v. Purdue Pharma, L.P.et al
Authors: Yakubi Hanna , Gac Brian , Apollonio Dorie E
Published: November 2022

Objective

Identify advertising strategies used to market opioids to women and children.

Design

Qualitative content analysis of internal pharmaceutical industry documents released in litigation, dated between 1999 and 2017.

Setting

USA.

Participants

Opioid manufacturers (Janssen, Ortho-McNeil, Purdue, Teva (Actavis), Janus, Cephalon); women; children.

Primary and secondary outcome measures

Advertising campaigns, industry executive statements regarding marketing goals

Methods

We examined ((DATASET) link:https://www.industrydocuments.ucsf.edu/drug/) documents released in State of Oklahoma v. Johnson & Johnson (2019) to identify marketing strategies and campaigns developed by opioid manufacturers that focused on children and women, as well as public records, including websites developed by manufacturers and their allies, to confirm whether marketing campaigns proposed in internal industry documents were implemented. Documents identified as relevant were coded for themes based on expectations drawn from previous research on marketing using internal industry documents, which included making emotional appeals and understating the risks of addiction.

Results

We found that opioid manufacturers sought to recruit coaches and school nurses to encourage opioid use by children, developed unbranded initiatives suggesting adolescents ask providers for pain care medications, suggested that opioid use could reduce health risks associated with untreated pain among women and advocated to policy makers that women faced unmet needs for pain medication.

Conclusions

The USA strictly regulates direct marketing of medications but does not place the same restrictions on indirect marketing and unbranded campaigns, which encourage people to seek treatment without indicating the names of specific products. Opioid manufacturers in the early 21st century appear to have relied largely on unbranded campaigns for marketing, which they described externally as public health promotion and internally as a way to increase sales of opioids. The rapid increase in opioid use concomitant with these campaigns suggests that additional scrutiny of this kind of marketing may be needed in order to protect vulnerable groups.
COVID-19 pandemic interim Foundation Year 1 post and confidence in core skills and competencies: a longitudinal survey
Authors: Gatti Cristina Angela , Parker-Conway Kathryn , Okorie Michael
Published: November 2022

Objectives

The interim Foundation Year 1 (FiY1) post was created in response to the COVID-19 pandemic to help bolster the workforce and manage increased clinical pressures. This study aimed to assess the impact of the FiY1 post on medical graduates’ self-reported confidence in common tasks, core skills, competencies and procedures prior to starting FY1, as a measure of increasing preparedness for practice.

Setting

A longitudinal survey was performed at a tertiary teaching hospital in the South East of England. FiY1 posts ran from June to July 2020.

Participants

Questionnaires were sent to 122 medical graduates from a single medical school (recipients included FiY1s and non-FiY1s) and to 69 FiY1s at a single Teaching Hospital NHS Trust, irrespective of medical school attended. Initial and follow-up questionnaires had 86 and 62 respondents, respectively. Of these, 39 graduates were matched; 26 were FiY1s and 13 non-FiY1s. The 39 matched results were analysed.

Primary outcome measures

Confidence levels in common FY1 tasks, core procedures and competencies were gathered before and after the FiY1 post through online questionnaires. Change in confidence comparing FiY1s and non-FiY1s was measured and analysed using linear regression.

Results

On a 5-point scale, the FiY1 post increased overall confidence in starting FY1 by 0.62 (95% CI 0.072 to 1.167, p=0.028). The FiY1 post increased confidence in performing venepuncture by 0.32 (95% CI 0.011 to 0.920, p=0.045), performing intravenous cannulation by 0.48 (95% CI 0.030 to 1.294, p=0.041) and recognising, assessing and initiating the management of the acutely ill patient by 0.32 (95% CI 0.030 to 1.301, p=0.041).

Conclusions

The COVID-19 pandemic FiY1 post improved confidence in core skills and competencies. These findings may help guide future educational interventions in conjunction with further larger scale studies, ultimately aiding to bridge the transition gap between being a medical student and a doctor.
Association between non-HDLC and 1-year prognosis in patients with spontaneous intracerebral haemorrhage: a prospective cohort study from 13 hospitals in Beijing
Authors: Wang Yu , Wu Jianwei , Wang Anxin , Jiang Ruixuan , Zhao Xingquan , Wang Wenjuan
Published: November 2022

Objectives

Previous studies suggested an inverse association between lipoprotein cholesterols and bleeding risk, while limited data were available about the predictive value of lipoproteins on intracerebral haemorrhage (ICH). Our recent research series showed that higher non-high-density lipoprotein cholesterol (non-HDLC) was an independent predictor of favourable 3-month outcome in ICH patients, we thus aimed to further investigate the association between non-HDLC levels and 1-year functional outcomes after ICH.

Design

Prospective multicentre cohort study.

Setting

13 hospitals in Beijing, China.

Participants

A total of 666 ICH patients were included between December 2014 and September 2016.

Methods

Non-HDLC was calculated by subtracting HDL-C from total cholesterol. Patients were then grouped by non-HDLC levels into three categories: <3.4 mmol/L, 3.4–4.2 mmol/L and ≥4.2 mmol/L. Both the univariate and multivariate logistic regressions were used to assess the association between non-HDLC levels and 1-year unfavourable functional outcomes (modified Rankin Scale ≥3) in ICH patients. Moreover, sensitivity analysis was performed in ICH patients without statin use after admission.

Results

There were 33.5% (223/666) ICH patients identified with unfavourable functional outcomes at 1-year follow-up. In the univariate analysis, patients who achieved non-HDLC levels above 4.2 mmol/L had a 49% decreased risk of 1-year poor prognosis (OR 0.51, 95% CI 0.33 to 0.81). However, non-HDLC did not retain its independent prognostic value in multivariate analysis, the fully adjusted OR values were 1.00 (reference), 1.06 (0.63, 1.79) and 0.83 (0.45, 1.54) from the lowest to the highest non-HDLC group. Moreover, statin use after ICH onset made no difference to the long-term prognosis.

Conclusions

Non-HDLC was not an independent predictor for 1-year functional outcome in ICH patients, irrespective of poststroke statin use. The predictive value of well-recognised confounding factors was more dominant than non-HDLC on long-term prognosis.
Effectiveness of subacromial injections in rotator cuff lesions: systematic review and meta-analysis protocol
Authors: Tossolini Goulart Luana , Matsunaga Fabio Teruo , Belloti João Carlos , Faloppa Flavio , Paim Thays Sellan , Tamaoki Marcel Jun Sugawara
Published: November 2022

Introduction

Subacromial injections are therapeutic options for rotator cuff injuries, with consistent results not well established yet for each drug applied. The objective of this systematic review and meta-analysis is to analyse the effectiveness of the substances used in subacromial injections for the treatment of rotator cuff injuries and shoulder impingement syndrome, considering the functional gain and pain improvement of the shoulder.

Methods and analysis

Beginning in November 2022, we will perform a detailed search using the MEDLINE/PubMed, EMBASE, Cochrane Central Register of Controlled Trials and LILACS databases. Relevant grey literature (reference lists, conference abstracts and academic papers) will also be included.

Two reviewers will independently screen and extract the information from the literature. Bias and quality of the included studies will be evaluated using the risk of bias assessment tool provided by the Cochrane Collaboration. Statistical analyses will be performed using Review Manager V.5.4 software.

Ethics and dissemination

Approval and patient informed consent are not required because we will only include published literature. The results of this research will be disseminated in a peer-reviewed journal and likely through other scientific events.

PROSPERO registration number

CRD42020199292.