bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Study on Butt-joint TC4/GH4169 Dissimilar Metals Prepared by Double Laser Assisted FSW
Authors: Xu Lifeng , Wang Tao , Zhou Yan , Wang Dongsheng
Published: May 2022

To verify validity of new method for preparing dissimilar metals with high melting point through double laser assisted friction stir welding (FSW), butt welding tests on dissimilar metals of TC4 and GH4169 were carried out by conventional FSW, single laser assisted FSW and double laser assisted FSW, respectively. Macroscopic morphology, microstructure and mechanical properties of butt-joint were analyzed. Results demonstrated that the conventional FSW surface is relatively rough, manifested by existence of many trims and rags, incomplete mixing of joint and dissimilar materials, as well as a certain proportion of pore defects. The single laser assisted FSW surface is even and smooth, manifested with few trims and rags. Compared with conventional FSW, the dissimilar material mixing is improved significantly, and there are few pores. The double laser assisted FSW surface shows the best quality, manifested by the fewest trims and rags. The mixing of dissimilar materials is further improved and the joint has good shaping, without obvious defects. Tensile strengths of joints of conventional FSW, single laser assisted FSW and double laser assisted FSW were 238 MPa, 423 MPa and 505 MPa, respectively. Laser assisted FSW has the higher tensile strength, which is attributed to the more complete material mixing and thicker layer of element diffusion. The laser preheating can decrease axial downward pressure of stirring head and radial stress of the stirring needle in the welding process significantly compared with those in conventional frictional stir welding. In particular, double laser preheating can make stresses on the stirring needle more uniform. This is conducive to mutual flowing and integration of dissimilar materials for FSW. Meanwhile, it can reduce the wearing loss between the stirring head and welding component. Double laser preheating can prolong service life of stirring heat significantly and it can improve welding speed significantly under the same rotating speed of the same stirring heat, thus enabling to increase welding efficiency.
High precision assembly test technology for space high reliability thermoelectric refrigeration system
Authors: Liu Xin , Zhao Benhua , Li Rongjun , Xiao Meng , Wang Shuai , Zhang Bin , Fan Yufeng
Published: May 2022

Space Thermoelectric cooler is a key component of cryogenic equipment, which is used for high efficiency refrigeration of spacecraft in orbit. Its assembly state directly determines the refrigeration effect and service life. At the same time, it is characterized by high brittleness and low strength. In the assembly to low temperature equipment, thermoelectric cooler is required to be closely connected with internal and external components to achieve seamless connection and efficient heat transfer. At the same time, it is necessary to prevent the damage caused by large compressive stress caused by excessive assembly load, so as to meet the purpose of long life, high reliability and stable operation. The stiffness curve of thermoelectric refrigerator was obtained by measuring the component displacement when the pressure was applied under the simulated thermoelectric refrigerator assembly state, which was used as the guiding parameter to guide the thermoelectric refrigerator assembly. Meanwhile, the damage of thermoelectric refrigerator under different pressure loads was checked. Explore the variation law of displacement under different preload of refrigeration components. Finally, the high precision assembly is realized by unified combination of thermoelectric refrigerator and structural components of refrigeration assembly to meet the requirements of high efficiency, high reliability and long life refrigeration of space cryogenic equipment.
The microstructure and tensile property changes of S31042 steel after long time service
Authors: Jin Xiao , Xia Xianxi , Zhu Baoyin , Zhao Yanfen , Duan Peng , Liang Jun , Du Jinfeng , Zhou Chao , Zhang Guodong
Published: May 2022

Ultra-supercritical power generation technology is one of the main solutions to the many contradictory problems of carbon emissions and environmental protection in coal-fired power plants. S31042 austenitic heat-resistant steel has become a typical material for high-temperature components used in ultra-supercritical units because of its good high-temperature creep properties and high-temperature corrosion resistance. In this study, typical characterization techniques such as SEM (Scanning Electron Microscopy), TEM (transmission electron microscopy), and EBSD (Electron Backscattered Diffraction) were used to observe the microstructure of S31042 austenitic heat-resistant steel, while the room-temperature tensile and high-temperature tensile properties of the material were tested under the corresponding conditions. The results show that the grain of S31042 heat-resistant steel after service is the same as that of the non-service samples, which is still twinned austenite. The room-temperature tensile properties and high-temperature tensile properties of S31042 after long service were almost unchanged.
Modified Waterborne Polyacrylate for Cotton Fiber Printing Development of prepolymer
Authors: Li Luowei , Lv Xiaodan , Chen Yanning , Huang Tingting , He Jiahong
Published: May 2022

In this paper, polyacrylate (PA) was modified by waterborne polyurethane (WPU) to synthesize waterborne polyurethane-acrylate coating material. The structural changes of each component before and after modification, emulsion performance, film performance and printing performance were studied. The effects of raw material ratio and process conditions on application performance of printing emulsion were explored. The results showed that under the conditions of drying temperature and time of 150 °C and 3 min, the optimal formula was resin coating (WPU : PA=4 : 6), mixed solvent, deionized water and pigment content of 25 %, 15 %, 45 % and 15 %, respectively. The obtained emulsion was stable, the water absorption and solvent resistance of the film were good, and the rubbing fastness of printing could reach 4–5 grade. The structural analysis showed that the polyacrylate emulsion was synthesized, and the modified emulsion had the composite structure of WPU/PA.
Effect of different Si addition on oxidation resistance of titanium aluminum coating at 900 °C
Authors: Liang Jing , Gao Yunfei , Liu Ye , Chen Suiyuan , Liu Changsheng
Published: May 2022

The Ti-6Al-4V substrate was used as the laser cladding material, and the fiber laser was used to scan and form a titanium-aluminum composite coating in situ. Ti5Si3 reinforcing phase is formed in situ by the reaction between Si and Ti in the base material, the oxidation behavior of 50 h at a high temperature of 900 °C was studied by adding different amounts of Si (0, 1.25, 2.5, 3.75 and 5 mol.%). The experimental results show that the mass gain of TC4 high temperature oxidation (50 h at 900 °C) is 120mg/cm2, and the titanium aluminum coating with different contents of Si decreases to 60, 45, 42, 30 and 40mg/cm2. The addition of Si (3.75 mol.%) in the coating greatly increases the oxidation resistance at high temperatures. The addition of Si inhibits the affinity of Ti and O elements, resulting in the Ti5Si3/γ-TiAl composite coating producing more Al2O3 at high temperatures, which is more dense than the Al2O3 produced by the loose Ti-6Al-4V substrate of TiO2. Under the condition of high temperature oxidation at 900 °C for 50 hours, the oxidation resistance of TiAl-3.75Si is the best at high temperature.
Facile synthesis of Co3O4 nanoparticles with different morphology for efficient water oxidation in alkaline media
Authors: Li Zhengsheng , Guo Ruitang , Lin Zhidong , Ji Xiangyin , Yuan Ye , Hong Longfei , Pan Weiguo
Published: May 2022

Hydrogen production from water electrolysis is an important measure to achieve clean and sustainable energy in the future. Oxygen evolution reaction is a half-reaction of water electrolysis process, and its efficiency has a great influence on the overall reaction. The morphology of the catalyst has a great influence on the catalytic performance of the catalyst for oxygen evolution, but the mechanism of the effect of the morphology on the activity is still unclear. Therefore, the influence of the catalyst morphology on the catalytic activity needs to be studied urgently. Co3O4 is widely used in oxygen evolution reactions. Therefore, we took three Co3O4 with different morphologies as the research objects to study the effect of morphology on the oxygen evolution activity of Co3O4. The results show that among the three different morphologies of cobalt tetroxide, the Co3O4 with porous sheet morphology exhibits the best oxygen evolution activity (η10 = 1.54 V in 1 M KOH). The reason for the better activity of cobalt tetroxide with the morphology of the hollow sheet may be due to its larger specific surface area and more active sites, which reduces the reaction electron transfer barrier. Our work sheds new light on the design of novel oxygen evolution electrocatalysts.
An experimental study on aviation kerosene pool fire flame and thermal radiation
Authors: Wei Ruichao , Wang Baowei , He Qize , Lian Liping , Huang Shenshi
Published: May 2022

In this study, small-scale aviation kerosene pool fire experiments were carried out. The experiments were conducted by measuring the flame temperature and plume temperature on the axis by thermocouples and obtaining 50% of the flame intermittency height from the images taken by the camera. Using the Heskestad’s model, the fitting result of flame height and pan size was obtained. Moreover, the surface emission power of aviation kerosene flame was calculated based on the cylindrical flame theory. The experimental data in this paper will contribute to studies of aviation kerosene fire simulations.
Research on a new designed upward turning comb of escalator
Authors: Feng Shuangchang , Chen Jie , Shen Wenhao
Published: May 2022

Escalator is an important transportation method for people in their daily life. The comb fixed at the entrance and exit is an important component of the escalator. Its function is to facilitate the transportation of passengers and prevent the escalator from being damaged by foreign matters to a certain extent. In order to avoid harm to passengers caused by the comb, the end of the comb should be made of easily broken material traditionally such as plastic and aluminum to ensure that the object can be released when clamped. This greatly increases the loss of comb and the repair time of maintenance personnel and leaves potential safety hazards. The article researches a new designed upward turning comb of escalator. The device comprises comb plate, mounting base, guide rod, spring, comb teeth, rotating shaft, upper baffle, chute, notch, mounting hole, long hole, guide hole, lower baffle, positioning block and arc push block. Compared with the prior technology, this new comb has the advantages of simple structure, convenient operation, repeated use, difficult to damage.
Analysis of stator rotor of rotating traveling wave ultrasonic motor
Authors: Cai Yi , Han Jingzhen , Li Yongfu , Liu Yang , He Guangteng
Published: May 2022

As a new type of energy exchange device, the operation characteristics of ultrasonic motor is a hot issue in current research. In this paper, the thermo-electro-mechanical coupling model of the stator and rotor of the rotary traveling wave ultrasonic motor is constructed by finite element software. The frequency and amplitude of the working mode of the stator and rotor of the ultrasonic motor under different temperature conditions are studied, and the influence of the piezoelectric ceramic lamination on the working state of the ultrasonic motor is discussed. The following conclusions are drawn: with the increase of temperature, the resonant frequency of the working mode of the ultrasonic motor B09 decreases and the amplitude increases slightly; piezoelectric ceramic delamination can improve the amplitude-frequency characteristics of stator and rotor. Considering comprehensively, the superposition of two layers of piezoelectric ceramic plates is the most suitable structure.
Taking 2oo3 as an example to study the improvement of Markov model considering periodic function test
Authors: Chen Peng , Lin Qinbei , Han XueFeng
Published: May 2022

In order to make the safety instrumented system meet the functional safety requirements of the classification in a longer period of time, and considering the model incompleteness of the original Markov model, we propose to add the consideration of periodic functional testing to the original Markov model for modeling. The results show that the PFDavg of the safety instrumented system with periodic functional testing is lower than that of the safety instrumented system without periodic functional testing, and the Markov model with periodic functional testing is more comprehensive and more consistent with the engineering reality.
Research and Implementation of Containerization for Virtual Instrumentation Measurement
Authors: Guo Wang
Published: May 2022

The instrumentation measurement system has fruitful achievements in various fields with cloud computing technology. However, the instrumentation cloud needs more PaaS (Platform-as-a-Service) capabilities to improve development and IT operations efficiency by expanding distributed measurement systems. In recent years, container and cloud-native technology growth have brought developing chances for instrumentation cloud. We propose a novel container and instrumentation communication architecture to apply container technology to virtual instrumentation. Firstly, we analyze the critical technologies of Container-Instrumentation communication architecture and give the solution of its implementation. Secondly, we develop and deploy the web backend and frontend to visualize measurement data with Kubernetes. Finally, completing the IV sweep measurement on the web demonstrates the feasibility of building the measurement system in a cloud-native way. So, the container-instrumentation architecture provides practical significance for constructing measurement systems and improving the instrumentation cloud capabilities with cloud-native architecture in the future.
Bias error in measurement of complex flow regime with ultrasonic flowmeter
Authors: Wang Zhili , Chen Qiutong , Li Danxun , Liu Shangwu
Published: May 2022

Ultrasonic flowmeters are widely used for flow measurement. We proposed a theoretical model to quantify the measurement error caused by the deviation of ultrasonic propagation trajectory in complex flow regimes. The three-dimensional ultrasonic propagation model is based on the assumption of ray acoustics. The results show that the trajectory offset of ultrasonic waves and velocity measurement errors in a three-dimensional non-uniform flow field is of the first order of the Mach number. Unlike gas flow, the Mach number of open channel flow is small, and the velocity measurement error of open channel ultrasonic flowmeter can be safely ignored.
Towards optical data transmission for high energy physics using silicon photonics
Authors: Prousalidi T. , Bulling A. , Court M. , Detraz S. , Lalović M. , Marcon L. , Olanterä L. , Orfanelli S. , Sandven U. , Scarcella C. , Sigaud C. , Soós C. , Troska J.
Published: May 2022

Future upgrades of CERN experiments will require low power optical data links to support ever-increasing data-rates at ever-higher radiation levels. Silicon photonics is a CMOS optoelectronic technology compatible with these requirements. We present the results of an optical transceiver proof of concept based on a silicon photonics integrated circuit coupled to existing radiation tolerant electronic ASICs.
Editorial announcements and information — ICFA Beam Dynamics Newsletter No. 83
Authors: Cai Y. , Piot P.
Published: May 2022

This is a general information article of the ICFA Beam Dynamics Newsletter No. 83. It contains two forewords from the Editor-in-Chief and the issue editor, a workshop and conference report section, a recent doctoral theses section, along with a forthcoming beam dynamics events section.
Optimization landscape in the simplest constrained random least-square problem
Authors: Fyodorov Yan V , Tublin Rashel
Published: May 2022

We analyze statistical features of the ‘optimization landscape’ in a random version of one of the simplest constrained optimization problems of the least-square type: finding the best approximation for the solution of a system of M linear equations in N unknowns: (
a

k
,
x
) = b

k
, k = 1, …, M on the N-sphere x
2 = N. We treat both the N-component vectors
a

k
and parameters b

k
as independent mean zero real Gaussian random variables. First, we derive the exact expressions for the mean number of stationary points of the least-square loss function in the overcomplete case M > N in the framework of the Kac-Rice approach combined with the random matrix theory for Wishart ensemble. Then we perform its asymptotic analysis as N → ∞ at a fixed α = M/N > 1 in various regimes. In particular, this analysis allows to extract the large deviation function for the density of the smallest Lagrange multiplier λ
min associated with the problem, and in this way to find its most probable value. This can be further used to predict the asymptotic mean minimal value

E

min

of the loss function as N → ∞. Finally, we develop an alternative approach based on the replica trick to conjecture the form of the large deviation function for the density of

E

min

at N ≫ 1 and any fixed ratio α = M/N > 0. As a by-product, we find the compatibility threshold
α
c < 1 which is the value of α beyond which a large random linear system on the N-sphere becomes typically incompatible.
One more time on the helicity decomposition of spin and orbital optical currents
Authors: Aiello Andrea
Published: May 2022

The helicity representation of the linear momentum density of a light wave is well understood for monochromatic optical fields in both paraxial and non-paraxial regimes of propagation. In this note we generalize such representation to nonmonochromatic optical fields. We find that, differently from the monochromatic case, the linear momentum density, aka the Poynting vector divided by c
2, does not separate into the sum of right-handed and left-handed terms, even when the so-called electric–magnetic democracy in enforced by averaging the electric and magnetic contributions. However, for quasimonochromatic light, such a separation is approximately restored after time-averaging. This paper is dedicated to Sir Michael Berry on the occasion of his 80th birthday.
Improvement of corrosion resistance and mechanical properties of chrome plating by diamond-like carbon coating with different silicon-based interlayers
Authors: Lakhonchai Anthika , Chingsungnoen Artit , Poolcharuansin Phitsanu , Chanlek Narong , Tunmee Sarayut , Rittihong Ukit
Published: May 2022

In this study, the silicon-based interlayers for hydrogenated amorphous carbon (a-C:H) coating on a chromium-plated substrate are presented. The a-Si, a-Si:N, a-Si:H and a-SixCy:H interlayers with a thickness of about 306 nm were deposited by direct current magnetron sputtering technique. The a-C:H films with a thickness of about 317 nm was prepared as a top layer by radio frequency-plasma chemical vapor deposition. The a-C:H films with silicon-based interlayers were characterized by x-ray photoelectron spectroscopy, Raman spectroscopy, field emission-secondary electron microscopy, nanoindentation, micro-scratching, and electrochemical corrosion measurements in terms of their structure, morphology, mechanical and adhesive properties, and corrosion resistance. The a-C:H films with an a-Si:H interlayer exhibit the lowest corrosion current density, which is about 36 times lower than that of the uncoated chromium-plated substrate. In addition, the hardness increases from 8.48 GPa for the uncoated substrate to 20.98 GPa for the a-C:H/a-Si:H sample. The mixing with hydrogen gas could reduce the residual oxygen during the deposition process, which could reduce the Si–O bonding and improve the adhesion strength between the a-C:H film and the a-Si:H interlayer and the a-Si:H interlayer and the substrate. Therefore, it can be concluded that the protective a-C:H coating with an a-Si:H interlayer has excellent potential to significantly improve the durability and extend the service life of materials used in abrasive and corrosive environments.
Surface modification of aluminum alloy 6061 by embedding B4C particles via friction stir processing
Authors: Yelamasetti Balram , Kumar P Naveen , G Venkat Ramana , Saxena Kuldeep K , Msomi Velaphi , H M Vishwanatha , Behera Ajit
Published: May 2022

Aluminum alloy-based surface composites have been in numerous applications since the introduction of the Friction Stir Processing (FSP) method to develop multifunctional properties owing to its ease of use and control in process parameters to obtain desired properties. AA6061-T651 is used as a substitute for AA6082 in structural applications due to its higher strength in comparison. To further improve the surface properties of AA6061, the friction stir processing technique was employed to reinforce Boron Carbide (B4C) particles by the Blind-Hole method. To achieve uniformity in distribution, FSP with a different direction strategy has been adopted. The surfaces thus developed were characterized using Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) techniques. The grain size measurement was made on the processed samples using Heyn lineal intercept method. Tension and microhardness tests were also conducted to study the change in mechanical properties. The dark carbide zones with clear boundaries were identified in single pass processed specimens. Uniformity in the B4C distribution was observed on the dual-pass surface. In addition, Energy-Dispersive Spectroscopy (EDS) results have shown the presence of B4C embedded regions in the nugget zones along with the AA6061 matrix. Higher ultimate tensile strength was observed with the single-pass processed surface by 11% than the dual-pass processed surface.
Behavior of multiple modes before and during minor disruption with the external resonant magnetic perturbations on J-TEXT tokamak
Authors: HUANG Mingxiang , REN Zhengkang , MAO Feiyue , YANG Zhoujun , GAO Yuan , ZHANG Zhichao , HE Shunfan , LI Guoliang , FAN Jinrong , TIAN Wei , WANG Nengchao , CHEN Zhipeng , DING Yonghua , PAN Yuan , CHEN Zhongyong
Published: May 2022

The behavior of multiple modes before and during minor disruption with the external resonant magnetic perturbations (RMPs) has been studied on a J-TEXT tokamak. The main component of RMPs is m/n = 2/1, where m and n are the numbers of the poloidal and toroidal modes, respectively. During the mode-locking caused by RMPs, it is found that before a minor or a major disruption (if there is no minor disruption), strong oscillations in both electron temperature and density occur if the edge safety factor q

a
> 3. The analysis shows that the oscillations are caused by the m/n = 3/1 mode. In addition, using the ECE, Mirnov coils and 2D electron cyclotron emission imaging diagnostic systems, it is found that a thermal collapse occurs on the inner side of the 2/1 magnetic island during the minor disruption, and before the collapse, a 3/2 island increases, after the collapse, the 3/2 island may disappear. Moreover, the study also shows that these 3/1, 2/1 and 3/2 modes play roles in the thermal collapse of disruptions.
Visualization of energy-environment-economy system research characteristics and hotspots evolution trends based on CiteSpace
Authors: Kao Xiaoxuan , Wang Wensheng , Kao Qingyun , Zhang Jianmin
Published: May 2022

With the recovery of the world economy, the increase in energy demand, global environmental pollution, climate change, and many other contradictory issues, after China proposed the Double-Carbon goal, research on the Energy-Environment-Economy system has attracted much attention. Through the visual analysis of Energy-Environment-Economy research literature, this paper provides scholars committed to this field with research characteristics and hotspots evolution trends in this field, and provides a direction guidance and practical method reference for subsequent research on Energy-Environment-Economy system-related issues. This study selected the literature from the Energy-Environment-Economy system field of Web of Science and CNKI database for nearly 20 years, uses CiteSpace to conduct research bibliometrics and visual analysis, and explores the main characteristics, research hotspots, and evolution trends of Energy-Environment-Economy system in Chinese and English. The research found that: ① there are many research results on Energy-Environment-Economy systems, and the research interest in the field of Energy-Environment-Economy systems continues to rise; ② the number of documents and research institutions in China ranks first in the world, and the influence of research results needs to be improved; ③ the hot topics of research topics in each period are bright, research hotspots evolve from single subsystems to systemic issues; ④ the attention to environment and climate change has increased significantly, and the evolutionary characteristics of research hotspots are in line with the development trend in reality.
An environmental cost basis for regulating aviation NOx emissions
Authors: Miller Cassandra J , Prashanth Prakash , Allroggen Florian , Grobler Carla , Sabnis Jayant S , Speth Raymond L , Barrett Steven R H
Published: May 2022

Combustion in aircraft engines results in the formation of nitrogen oxides (NOx) and carbon dioxide (CO2), among other species. NOx impacts air quality and is an indirect contributor to radiative forcing, while CO2 is a long-lived greenhouse gas. The International Civil Aviation Organization sets limits on NOx emissions from commercial aircraft, where for engines with a rated thrust greater than 89 kN the allowable NOx production per unit rated thrust is defined as a function of engine overall pressure ratio (OPR). This definition links the engine thermodynamic cycle, and implicitly fuel burn and CO2 emissions, to allowable NOx levels. These regulations have historically been evaluated and implemented with a focus on reducing adverse air quality impacts around airports, but the thermodynamic efficiency tradeoff with CO2 requires additional analysis to quantify net environmental impacts. This paper introduces a social cost basis for evaluating aviation NOx emissions regulations and quantifies the implied CO2 and NOx attributable air quality damage, climate damage, and fuel costs associated with the emissions standard. We show that higher overall pressure ratio engines operating at the current NOx regulatory limit are allowed more environmental damage per unit rated thrust than lower overall pressure ratio engines, resulting in variable social costs per unit thrust (i.e. fuel and environmental costs combined) across the engine design space. This is a consequence of the definition of the regulation today, where higher pressure ratio engines are allowed higher NOx emissions. Alternative regulation definitions are evaluated which consider the engine cycle and combustor together. Achieving constant social costs requires a regulatory limit where the increase in allowed NOx emissions tapers off at higher pressure ratios, corresponding to the diminishing marginal efficiency improvements due to increasing OPR in that region.
Dispersive interactions between standard and Dirac materials and the role of dimensionality
Authors: Le Dai-Nam , Rodriguez-Lopez Pablo , Woods Lilia M
Published: May 2022

The van der Waals (vdW) interaction plays a prominent role between neutral objects at separations where short ranged chemical forces are negligible. This type of dispersive coupling is determined by the interplay between geometry and response properties of the materials making up the objects. Here, we investigate the vdW interaction between 1D, 2D, and 3D standard and Dirac materials within the Random Phase Approximation, which takes into account collective excitations originating from the electronic Coulomb potential. A comprehensive understanding of characteristic functionalities and scaling laws are obtained for systems with parabolic energy dispersion (standard materials) and crossing linear bands (Dirac materials). By comparing the quantum mechanical and thermal limits the onset of thermal fluctuations in the vdW interaction is discussed showing that thermal effects are significantly pronounced at smaller scales in reduced dimensions.
The impact of frailty on short-term mortality following primary total hip and knee arthroplasty due to osteoarthritis
Authors: Cook Michael J , Lunt Mark , Board Timothy , O’Neill Terence W
Published: May 2022

Background

We determined the association between frailty and short-term mortality following total hip and knee arthroplasty (THA/TKA) for osteoarthritis and also the impact of THA/TKA on short-term mortality compared with a control population.

Methods

Frailty was assessed using a frailty index (categorised: fit, mild, moderate, severe frailty). The association between frailty and short-term mortality following THA/TKA was assessed using Cox regression. Mortality following THA/TKA was also compared with a control population with osteoarthritis but no previous THA/TKA, matched on year of birth, sex and quintile of index of multiple deprivation.

Results

A total of 103,563 cases who had a THA, 125,367 who had a TKA and matched controls contributed. Among those who had surgery, mortality increased with increasing frailty; adjusted hazard ratio (HR) (95% CI) at 30 days in severely frail versus fit: following THA, 2.85 (1.84, 4.39) and following TKA, 2.14 (1.29, 3.53). The predicted probability of 30-day mortality following THA/TKA varied by age, sex and frailty: following THA, from 0.05% among fit women aged 60–64 years to 6.55% among men with severe frailty aged ≥90 years. All-cause 30-day mortality was increased in fit cases following THA and TKA, respectively, versus fit controls (adjusted HR (95% CI), 1.60 (1.15, 2.21) and 2.98 (1.81, 4.89)), though not among cases with mild, moderate or severe frailty versus controls in the same frailty category.

Conclusion

Short-term mortality increased with increasing frailty following THA/TKA. Comparison of mortality among cases and controls may be affected by a ‘healthy surgery’ selection effect.
Pathology Residency Curricula
Authors: Katsakhyan Levon , Preciado Christopher , Baloch Zubair W
Published: May 2022

Objectives

To perform a systematic review of the published literature on pathology graduate medical education, with a focus on novel educational curricula.

Methods

We systematically searched the PubMed and Embase databases for relevant articles published between 2000 and 2021.

Results

We analyzed 612 articles and selected 19 peer-reviewed, full-length, English language articles published between 2003 and 2021 describing unique curricula for final review. Details on the general characteristics, conceptualization, design, implementation, and assessment were collected and discussed.

Conclusions

This systematic review highlights a recent increase in published curricular endeavors specifically addressing topics of educational need that are otherwise not commonly taught in traditional residency training. Curricula are diverse in their teaching methods, implementation, and originating institutions. The lack of meaningful evaluated outcomes and available curricular materials may hinder wider use of such curricula; these should be considered by future pathology educators undertaking their design.
Helium Plasma-Assisted Breast Reduction: A Pilot Study
Authors: Moncada Seraphine , Nichols Christopher
Published: May 2022

Background

Reduction mammaplasty and mastopexy are currently some of the most performed breast procedures. Techniques typically involve deepithelialization of the nipple-areola complex pedicle. Traditionally, scalpel or scissor dissection is performed below the basal skin layer to remove the germinal epithelium but above the subcutis to preserve the subdermal vascular plexus. Deepithelialization thus leaves a strong dermal “leash” for the pedicle while preserving the subdermal blood supply. This process is time intensive and bloody, and often an assistant is required for countertraction. Previously, authors have described laser-assisted breast reduction surgery as an alternative to traditional cold knife techniques. The advent of helium plasma generators offers another option for deepithelialization. This study is a preliminary assessment of the safety and efficacy of this application.

Objectives

The authors performed a prospective pilot study of 10 patients who underwent outpatient, inferior pedicle, breast reduction mammaplasty, or mastopexy surgery by a single surgeon. Outcomes were assessed for safety and efficacy. Representative tissue samples were evaluated by an independent pathology group.

Methods

All patients received standard outpatient perioperative care. Deepithelialization was performed using the Renuvion helium plasma device (Apyx Medical, Clearwater, FL), and standard breast reduction or mastopexy was performed.

Results

No major complications occurred in our series. Minor complications occurred in 1 patient (10%). No inclusion cysts were recorded in any patients.

Conclusions

Helium plasma energy for deepithelialization in breast reduction was found to be safe, efficient, and effective. Decreased operating room time and blood loss suggest that helium plasma is a potential alternative for surgeons who have access to this technology.

Level of Evidence: 5
BITES: balanced individual treatment effect for survival data
Authors: Schrod S , Schäfer A , Solbrig S , Lohmayer R , Gronwald W , Oefner P J , Beißbarth T , Spang R , Zacharias H U , Altenbuchinger M
Published: May 2022

Motivation

Estimating the effects of interventions on patient outcome is one of the key aspects of personalized medicine. Their inference is often challenged by the fact that the training data comprises only the outcome for the administered treatment, and not for alternative treatments (the so-called counterfactual outcomes). Several methods were suggested for this scenario based on observational data, i.e. data where the intervention was not applied randomly, for both continuous and binary outcome variables. However, patient outcome is often recorded in terms of time-to-event data, comprising right-censored event times if an event does not occur within the observation period. Albeit their enormous importance, time-to-event data are rarely used for treatment optimization. We suggest an approach named BITES (Balanced Individual Treatment Effect for Survival data), which combines a treatment-specific semi-parametric Cox loss with a treatment-balanced deep neural network; i.e. we regularize differences between treated and non-treated patients using Integral Probability Metrics (IPM).

Results

We show in simulation studies that this approach outperforms the state of the art. Furthermore, we demonstrate in an application to a cohort of breast cancer patients that hormone treatment can be optimized based on six routine parameters. We successfully validated this finding in an independent cohort.

Availability and implementation

We provide BITES as an easy-to-use python implementation including scheduled hyper-parameter optimization (https://github.com/sschrod/BITES). The data underlying this article are available in the CRAN repository at https://rdrr.io/cran/survival/man/gbsg.html and https://rdrr.io/cran/survival/man/rotterdam.html.

Supplementary information

Supplementary data are available at Bioinformatics online.
Distributed brain co-processor for tracking spikes, seizures and behaviour during electrical brain stimulation
Authors: Sladky Vladimir , Nejedly Petr , Mivalt Filip , Brinkmann Benjamin H , Kim Inyong , St. Louis Erik K , Gregg Nicholas M , Lundstrom Brian N , Crowe Chelsea M , Attia Tal Pal , Crepeau Daniel , Balzekas Irena , Marks Victoria S , Wheeler Lydia P , Cimbalnik Jan , Cook Mark , Janca Radek , Sturges Beverly K , Leyde Kent , Miller Kai J , Van Gompel Jamie J , Denison Timothy , Worrell Gregory A , Kremen Vaclav
Published: May 2022

Early implantable epilepsy therapy devices provided open-loop electrical stimulation without brain sensing, computing, or an interface for synchronized behavioural inputs from patients. Recent epilepsy stimulation devices provide brain sensing but have not yet developed analytics for accurately tracking and quantifying behaviour and seizures. Here we describe a distributed brain co-processor providing an intuitive bi-directional interface between patient, implanted neural stimulation and sensing device, and local and distributed computing resources. Automated analysis of continuous streaming electrophysiology is synchronized with patient reports using a handheld device and integrated with distributed cloud computing resources for quantifying seizures, interictal epileptiform spikes and patient symptoms during therapeutic electrical brain stimulation. The classification algorithms for interictal epileptiform spikes and seizures were developed and parameterized using long-term ambulatory data from nine humans and eight canines with epilepsy, and then implemented prospectively in out-of-sample testing in two pet canines and four humans with drug-resistant epilepsy living in their natural environments. Accurate seizure diaries are needed as the primary clinical outcome measure of epilepsy therapy and to guide brain-stimulation optimization. The brain co-processor system described here enables tracking interictal epileptiform spikes, seizures and correlation with patient behavioural reports. In the future, correlation of spikes and seizures with behaviour will allow more detailed investigation of the clinical impact of spikes and seizures on patients.
Co-culture of Schwann cells and endothelial cells for synergistically regulating dorsal root ganglion behavior on chitosan-based anisotropic topology for peripheral nerve regeneration
Authors: Zheng Tiantian , Wu Linliang , Sun Shaolan , Xu Jiawei , Han Qi , Liu Yifan , Wu Ronghua , Li Guicai
Published: May 2022

Background

Anisotropic topologies are known to regulate cell-oriented growth and induce cell differentiation, which is conducive to accelerating nerve regeneration, while co-culture of endothelial cells (ECs) and Schwann cells (SCs) can significantly promote the axon growth of dorsal root ganglion (DRG). However, the synergistic regulation of EC and SC co-culture of DRG behavior on anisotropic topologies is still rarely reported. The study aims to investigate the effect of anisotropic topology co-cultured with Schwann cells and endothelial cells on dorsal root ganglion behavior for promoting peripheral nerve regeneration.

Methods

Chitosan/artemisia sphaerocephala (CS/AS) scaffolds with anisotropic topology were first prepared using micro-molding technology, and then the surface was modified with dopamine to facilitate cell adhesion and growth. The physical and chemical properties of the scaffolds were characterized through morphology, wettability, surface roughness and component variation. SCs and ECs were co-cultured with DRG cells on anisotropic topology scaffolds to evaluate the axon growth behavior.

Results

Dopamine-modified topological CS/AS scaffolds had good hydrophilicity and provided an appropriate environment for cell growth. Cellular immunofluorescence showed that in contrast to DRG growth alone, co-culture of SCs and ECs could not only promote the growth of DRG axons, but also offered a stronger guidance for orientation growth of neurons, which could effectively prevent axons from tangling and knotting, and thus may significantly inhibit neurofibroma formation. Moreover, the co-culture of SCs and ECs could promote the release of nerve growth factor and vascular endothelial growth factor, and up-regulate genes relevant to cell proliferation, myelination and skeletal development via the PI3K-Akt, MAPK and cytokine and receptor chemokine pathways.

Conclusions

The co-culture of SCs and ECs significantly improved the growth behavior of DRG on anisotropic topological scaffolds, which may provide an important basis for the development of nerve grafts in peripheral nerve regeneration.
Exosomal PD-L1 predicts response with immunotherapy in NSCLC patients
Authors: Wang Yuting , Niu Xiaomin , Cheng Yirui , Zhang Yanshuang , Xia Liliang , Xia Weiliang , Lu Shun
Published: May 2022

Immune Check-Point Inhibitors (ICIs) have shown remarkable promise in treating tumors, including non-small cell lung cancer (NSCLC). Nevertheless, the treatment response rate is low. Studies have found that the high expression of exosomal PD-L1 is one of the reasons for the low treatment response. Therefore, this study focused on the relationship between the exosomal PD-L1 and the clinical response to immunotherapy in NSCLC patients to evaluate whether it could be used as a biomarker to predict the efficacy of ICIs. In this study, clinical information and blood samples of 149 NSCLC patients receiving ICIs were collected. The expression level of exosomal PD-L1 was detected by enzyme-linked immunosorbent assay method, and the relationship between exosomal PD-L1 and the efficacy of ICIs was explored. Overall, our study found that the expression level of exosomal PD-L1 was lower at pre-treatment, or the max fold increasing change higher at 3–6 weeks had a higher disease control rate and longer progression-free survival. It revealed that the exosomal PD-L1 was associated with the treatment response of patients using ICIs and provided a new tool for the evaluation of clinical efficacy of lung cancer immunotherapy.
Towards a mechanistic understanding of microalgae–bacteria interactions: integration of metabolomic analysis and computational models
Authors: Daly Giulia , Ghini Veronica , Adessi Alessandra , Fondi Marco , Buchan Alison , Viti Carlo
Published: May 2022

Interactions amongst marine microalgae and heterotrophic bacteria drive processes underlying major biogeochemical cycles and are important for many artificial systems. These dynamic and complex interactions span the range from cooperative to competitive, and it is the diverse and intricate networks of metabolites and chemical mediators that are predicted to principally dictate the nature of the relationship at any point in time. Recent advances in technologies to identify, analyze, and quantify metabolites have allowed for a comprehensive view of the molecules available for exchange and/or reflective of organismal interactions, setting the stage for development of mechanistic understanding of these systems. Here, we (i) review the current knowledge landscape of microalgal–bacterial interactions by focusing on metabolomic studies of selected, simplified model systems; (ii) describe the state of the field of metabolomics, with specific focus on techniques and approaches developed for microalga–bacterial interaction studies; and (iii) outline the main approaches for development of mathematical models of these interacting systems, which collectively have the power to enhance interpretation of experimental data and generate novel testable hypotheses. We share the viewpoint that a comprehensive and integrated series of -omics approaches that include theoretical formulations are necessary to develop predictive and mechanistic understanding of these biological entities.
Associations Between Use of Paid Help and Care Experiences Among Medicare–Medicaid Enrolled Older Adults With and Without Dementia
Authors: Fabius Chanee D , Okoye Safiyyah M , Mulcahy John , Burgdorf Julia G , Wolff Jennifer L
Published: May 2022

Objectives

Community-living older Medicare and Medicaid enrollees (“dual-enrollees”) have high care needs and commonly receive paid and unpaid long-term services and supports (LTSS) to help with routine activities. Little is known about whether receiving paid help or individuals’ state and neighborhood environmental context (“LTSS environment”) relates to dual-enrollees’ care experiences.

Methods

We examine a sample of n = 979 community-dwelling dual-enrollees with disabilities from 2011 to 2015 National Health and Aging Trends Study, linked to measures of neighborhood disadvantage and state Medicaid home and community-based services (HCBS) generosity. Logistic regression models stratified by dementia status assess associations between paid help and: (a) adverse consequences due to unmet care needs, and (b) participation restrictions in valued activities, among dual-enrollees with and without dementia, adjusting for individual and LTSS environmental characteristics.

Results

Use of paid help was greater for those with (versus without) dementia (46.9% vs. 37.8%). Neighborhood disadvantage was associated with greater use of paid help among dual-enrollees living with dementia. High state Medicaid HCBS generosity was associated with the use of paid help, regardless of dementia status. Dual-enrollees with dementia receiving paid help had higher odds of experiencing adverse consequences due to unmet need (adjusted odds ratio = 2.05; 95% confidence interval 1.16–3.61; p = .02)―no significant associations were observed for participation restrictions. Use of paid help and LTSS environment were not significantly associated with care experiences for dual-enrollees without dementia.

Discussion

Findings highlight the complexities of caring for dual-enrollees, particularly those with dementia, and emphasize the need to strengthen the delivery of paid care with considerations for the LTSS environment.
Multimethod palaeointensity results from a rapidly emitted upper Miocene lava flow sequence in São Vicente (Cape Verde): new data for the African record
Authors: Calvo Rathert M , Carrancho Á , Morales J , Pérez-Rodríguez N , Lebedev V A , Caccavari A , Vegas N , Goguitchaichvili A
Published: May 2022

We present new radiometric ages and full-vector palaeomagnetic data from São Vicente Island, Cape Verde. Samples were obtained from a sequence of 11 flows. A K-Ar age determination was performed on the lowermost flow of the sequence, yielding an upper Miocene age of 6.07 ± 0.16 (2σ) Ma. Considering the normal polarity observed in all flows, the age of the sequence could be narrowed down to an interval between 6.03 and 6.23 Ma.

The mean palaeomagnetic direction of the studied sequence was compared with the expected direction, calculated from the African Apparent Polar Wander Path (5 Ma). While inclinations approximately agree, the palaeodeclination appears westwardly deviated by 26.5° ± 2.9°. Moreover, nearly no scatter of virtual geomagnetic poles around their mean value is observed and its comparison with the scatter observed in palaeomagnetic directions obtained from geomagnetic field model SHA.DIF.14k suggests that the sequence was very rapidly emplaced in only a few centuries. Thus, the obtained anomalous palaeomagnetic direction seems to reflect the effect of non-averaged secular variation, although a local vertical-axis counter-clockwise rotation of the sequence, cannot be entirely ruled out.

Thellier–Coe palaeointensity experiments on 66 specimens yielded 22 successful determinations and multispecimen (MS) palaeointensity experiments on 11 samples yielded 8 successful determinations. In the upper part of the sequence, Thellier–Coe determinations fail due to the presence of multidomain (MD) grains, but the MS method yields successful results in several of these flows, demonstrating that this method can provide reliable palaeointensity determinations on samples with a higher MD grain fraction. A mean palaeointensity BSV = (18.5 ± 1.9) µT is obtained from the joint analysis of the results from both methods. This value lies clearly below the present-day value BP = 33.1 μT. The virtual axial dipole moment (VADM = 4.3 × 1022 Am2), however, cannot be considered anomalous if compared to available upper Miocene–Pliocene data and represents a new high-reliability contribution to the very limited African palaeointensity database.