bluuebunny/crossref_metadata_2025 huggingface dataset:
Atomistic Study on the Cooling Rate Induced Mechanical Properties Variations in Additively Manufactured Inconel-718
Authors: Islam Toushiqul , Aziz Md Samin Ashiq , Motalab Mohammad , Faiyad Abrar
Published: February 2024

Inconel 718 is a highly sought-after material for use in additive manufacturing, which is also known as 3D printing. Additive manufacturing is a process of building three-dimensional objects by layering materials on top of one another, based on a computer-generated design. Inconel 718 is very popular in additive manufacturing because of its unique properties, including high strength, high-temperature resistance, and excellent corrosion and oxidation resistance. This paper uses atomistic tensile test simulation to investigate the mechanical properties of additively manufactured Inconel 718. The study explores the effects of different cooling rates on Inconel-718 material using the large-scale atomic/molecular massively parallel simulator (LAMMPS). Throughout this study, the added layers on a pristine substrate have been equilibrated at 2000K and subsequently cooled to 300K using a cooling rate ranging from 5 K/ps to 100 K/ps including a variable cooling rate. Embedded atom method (EAM) potential has been used to investigate the dislocations, voids, defects, and atomic interactions, which control the material properties and failure mechanisms. A nano bar of (22nm × 5.5 nm × 5.5 nm) has been cut from the solidified layer for tensile test. The tensile force has been applied along [001] direction. The strain rate has been varied from 108 s−1 to 1010 s−1. Tensile test simulation shows that the additively manufactured Inconel 718 has a lower yield strength and elongation than the conventionally manufactured material but exhibits comparable ultimate tensile strength. The results show that the variation of cooling rate significantly impacts the mechanical properties, demonstrating that increasing the cooling rate causes the final material to have a lower density, higher number of defects, and lower Young’s modulus. In contrast, lower cooling rates cause the final structure to exhibit properties similar to its pristine counterpart.

These MD simulations provide insights into the deformation behavior, ultimate tensile strength, Young’s Modulus, fracture strain, and dislocation density at the atomic level and suggest that the observed differences in mechanical properties can be attributed to the presence of defects and microstructural features induced by different cooling rates of the additive manufacturing process. The fracture evolution at different cooling rates has also been analyzed. Results from this computational study also show that extensive sliding in {111} shear plane that again depends on the cooling rate causes necking before fracture. Overall, the findings highlight the importance of careful process control in additive manufacturing and demonstrate the potential of MD simulations for predicting the mechanical behavior of such materials.
Recovering and Regenerating of Spent Anode Material From the Scrap of Used Lithium Ion Batteries
Authors: Al-Shammari Hammad , Farhad Siamak
Published: February 2024

Lithium-ion batteries (LIBs) have been used intensively as energy storage for products powered by electricity, such as phones, laptops, electric vehicles, etc. Nevertheless, the increasing usage of LIBs is estimated to grow in the upcoming years due to the involvement of the technology of the electric vehicle. Therefore, the spent LIBs will increase in parallel to the demand growth which considers an obstacle to the environment as well as the economy in case left without recycling. So far, there are some recycling procedures that are focusing on the valuable metals existed in the spent cathode active materials, such as Ni, Co, and Li. However, the anode active material (graphite) in most cases consider as a waste. In this paper, the focus will be in an environmentally friendly and practical method for regenerating the spent anode active material. The aim of this study is to recover the anode material from the scrap of LIBs that contains the most popular types of LIBs such as LCO, LFP, LMO, NMC, and NCA. Then, the recovered anode active material will be heat treated to enhance its properties before being regenerated in a new LIB and farther evaluated.

For the validation, an experiment was designed where a scrap of used LIBs has physically separated and the recovered anode active material has directly regenerated in new cells and evaluated by galvanostatic cycling. Finally, the results of the SEM/EDX show that the anode and cathode mixture materials have separated from each other completely within a short time (typically 0.2 sec). Also, the performance of the regenerated anode is very close to the performance of the commercial anode material indicating the validity of the regeneration process.
The Effect of Char Particle Morphology on the Drag Coefficient Under Combustion Condition Using Micro-CT and Particle-Resolving Simulation
Authors: Liang Dongyu
Published: February 2024

The study of solid fuel combustion and gasification is crucial for the development of clean and efficient energy systems, especially in light of concerns about climate change and environmental contamination. With Computational fluid dynamics (CFD) that is widespread in combustion and gasification studies, an accurate description, in numerical simulations of multiphase flows, of the interphase momentum exchange is crucial. The drag force coefficient based on the individual char particles which affects the final outcomes of the reactor-scale simulation is used to describe this interaction. However, the existing drag correlation models that are typically introduced in the reactor scale CFD simulations are established based on non-realistic particle morphology. The effects of the roughness of particle surface, and the irregular particle shape are normally neglected. Therefore, this study focuses on the morphology effect of real solid fuel char particles on drag coefficient with conversion reactions at low Reynolds number (Re = 20), comparing it to regular shapes such as spheres and cylinders. Micro-CT imaging and particle-resolving simulations are used to investigate the drag coefficient of real solid fuel particles under combustion conditions. The findings of this study highlight that the traditional approach of treating real char particles as idealized shapes such as spheres or cylinders may not accurately represent their movement with chemical reactions. The empirical drag coefficients used in this study still have limitations and require further improvement to accurately capture the complex nature of real char particles.
Cyber-Protection of a Wheel Rotational Kinematics Sensor for Agile Mobility
Authors: Paldan Jesse , Vantsevich Vladimir , Gorsich David , Vitta Pradeep , Moradi Lee
Published: February 2024

The modern ground vehicle has become a set of systems containing interconnected sensors, actuators, and embedded control systems and therefore the security of vehicles with Intelligent Physical Systems (IPS) responsible for vehicle motion and performance has become vital. Electromagnetic radiation has the potential to physically interfere with the operation of IPS components including sensors while bypassing typical methods of intrusion detection and thus negatively impact vehicle performance. Traditionally, cyber-security issues are considered in relation with software design. However, it is important to estimate and provide cyber security of vehicle mechatronic intelligent and cyber-based systems. From this perspective, a model of a new wheel rotational kinematics sensor is examined in the presence of an electromagnetic cyber-threat to the sensor’s signal. In this paper, an analysis of the sensor’s susceptibility to and potential protection from intentional electromagnetic interference (IEMI) is performed in transient terrain conditions when the wheels move from one terrain to another. A simulated IEMI attack is applied to the sensor model to examine the impact of the degraded signal on the quality of tire slippage and rolling radius estimation. The shielding effectiveness needed to maintain reliability of the signal, allowing it to provide a signal of the wheel rotational velocity under threat very close to the signal during the normal operation, is estimated.
Wavelet Based Nonlinear Time-Frequency Control Theory With Local Adaptability
Authors: Kuo Chi-Wei , Suh C. Steve
Published: February 2024

A novel nonlinear control concept featuring simultaneous control of vibration amplitude in the time domain and spectral response in the frequency domain is developed and subsequently incorporated to maintain dynamic stability in these nonlinear dynamics by denying bifurcation and route-to-chaos from coming to pass. This study mathematically examines the time-frequency control theory and derives the ranges of the regression step sizes that ensure fast convergence and solution stability of the controller design. The local adaptability is novel, intelligent, self-adjusting, and universally applicable to addressing bifurcated and chaotic responses. Incorporating the control theory into designing dynamic systems governed by discontinuous, time-delayed nonlinear oscillators would realize unconditional stability, high-performance quality, and operation efficiency.

In the end, a novel time-delayed vibro-impact oscillator was investigated. Its instability in manufacturing would result in premature tool breakage, increased wear rate, and poor workpiece quality. Improvements in the discontinuous system in performance and stability were consequential in implementing the wavelet-based time-frequency controller with parallel online modeling. The controller demonstrated the most unique property in the frequency domain. As was evident in the instantaneous frequency domain, the controlled motions of the oscillator were unconditionally stable, stationary, and periodic.
Effects of Various Baffle Designs on Center of Gravity Deviation in a Training Aircraft Wing Fuel Tank Using 1D Simulations
Authors: Karahan Kerem , Cadirci Sertac
Published: February 2024

There are baffle components in aircraft fuel tanks to damp sloshing effects and prevent Center of Gravity (CoG) traveling from its initial location. These baffles have significant role in damping forces, moments acting on aircraft body and CoG deviation. Ribbed baffles have cutout holes on its surface as design details. These cutout holes directly affect CoG deviation amount and retreat duration of deviated CoG in the tank. In this study, various cutout designs and aircraft wing tank geometries were modeled with Siemens NX CAD modeling program. These various designs were used in 1D and transient CFD sloshing analyses, then effects of different designs were investigated.1D analyses were constructed using Siemens Amesim program and they were managed in order to get initial conditions for further CFD analyses. As an input, bank-to-bank maneuver acceleration was applied along 10 seconds on aircraft body with 45° roll angle. At the end of acceleration, simulations were conducted until steady conditions were met in order to get retreat duration. The aim of the 1D analyses was to achieve minimum deviation amount and minimum retreat duration that will be assumed to be the most desirable case. Transient 3D CFD analyses have been performed with Siemens StarCCM+ in order to obtain most realistic solutions. For the optimum cases, CFD simulations were conducted using multi-phase sloshing flow of jet fuel (JP8) and air using Volume of Fluid (VOF) method. Thus, much detailed information about CoG deviation, retreat duration, sloshing effects of free surface fluctuations and 3D turbulent eddies became observable from CFD simulations. As a result, optimum performance efficiency of baffles was considered as lower CoG deviation distance and shorter retreat duration.
The Hydrodynamic Benefits Achieved Through Lateral Spacing of Schooling Manta Rays
Authors: Huang Zihao , Menzer Alec , Guo Jiacheng , Dong Haibo
Published: February 2024

Direct numerical simulation of a two-manta-ray-model school is performed to study the effects of lateral distances on the hydrodynamic performance of the manta rays. An in-house numerical solver based on the immersed boundary method is adopted to perform this study. Clear trends in performance can be observed, with the highest cycle-averaged thrust enhancement of 32% on the tandem follower compared to that of a solitary swimmer. A leading-edge vortex (LEV) enhancement is found on the tandem follower at the moment of thrust enhancement. It is also found that within 1.5 span length (SL) in the lateral direction, the follower exhibits a propulsive advantage, while the leader’s performance remains nearly the same. Low surface pressure regions are observed at the front of the follower, which induces forward suction force to enhance the follower’s performance. The near-body vortex topology is studied, and the tandem follower’s circulation strength shows improvements along the spanwise direction in both the downstroke and upstroke. Far wake topology observations are made to compare all cases.
Improvement of Standard K-Epsilon Turbulence Model for Round Free Jets by Adjusting Closure Coefficients
Authors: Turutoglu Cem , Cadirci Sertac
Published: February 2024

In this study, round free jet was modeled with standard k-ε turbulence model and the results were compared with the measurements. The aim of the study is to improve the prediction capability of standard k-ε turbulence model, that is not very successful in modeling flows with anisotropic Reynolds stress tensors such as jet flows. It was aimed to investigate the effect of model constants such as Cε1, the coefficient of turbulent production; Cε2, the coefficient of turbulent kinetic energy dissipation and Cμ, used to calculate turbulence viscosity. Steady-state and three-dimensional CFD analyses have been performed for these constants and the results were evaluated based on dimensionless velocity and turbulence profiles, jet half-thicknesses, centerline velocity and turbulence intensity (TI) on the jet axis. It was observed that the adjusted new constants achieve more successful results than the default coefficients. By calibrating the model coefficients that differ from the default model coefficients by 16% for Cε1, 17% for Cε2, and 1.2% for Cμ, it is revealed that jet centerline velocity distribution and jet half-width distribution along the jet axis can be estimated better. The new closure coefficients were also validated for Reynolds numbers of 5000 and 20000. The CFD simulations revealed that the velocity-profile change with the adjusted model coefficients and the numerical results agreed well with the experimental data. By this way, the calculation errors due to uncertainty of turbulence modeling encountered in some CFD calculations is reduced.
A Simplified Methodology to Predict Performance of IC Engines Operating With Bio-Syngas
Authors: Sabnis Sandeep P. , Seethamraju Srinivas
Published: February 2024

Biogas is one of the sustainable fuels that can be obtained from biomass using anaerobic digestion, and can be used as an IC Engine fuel. However, it has a low calorific value owing to the high CO2 content (∼40 vol%). Hence, one can use reforming to convert the biogas into bio-syngas that has an improved calorific value due to the presence of H2 and CO in addition to CH4. However, the effect of the reformed bio-syngas composition on the performance of the IC engines needs to be investigated to ascertain the economic feasibility of the entire process.

Experimental investigations on IC engines with the alternate fuel mixture can be used to estimate the performance of the engine. However, these are expensive and time-consuming. An alternative approach is the use of advanced simulation models, which are also complex and require experimental data for validation. Therefore, a quick and alternative estimation method is needed.

A methodology is proposed in this work to quickly estimate the engine performance for syngas using available data and knowledge in the literature. Initially, the cumulative heat release data for a known fuel is normalized to find the mass fraction burned (MFB). The Weibe function representing the combustion in the engine is established from the MFB data. These Weibe function parameters (efficiency factor “a” and form factor “m”) are then utilized to predict the performance of another fuel which is proposed to be evaluated using a simple 0-D single zone simulation. The criteria to correlate the combustion dynamics of one fuel to another is the matching of H2/COx ratios of the two fuels. The simulation results are also used to calculate other important parameters, viz. temperature profile, cycle work, IMEP and indicated thermal efficiency.
Grid Convergence Properties of Wall-Modeled Large-Eddy Simulations in the Asymptotic Regime
Authors: Yang Xiang , Abkar Mahdi
Published: February 2024

This study explores the grid convergence properties of wall-modeled large-eddy simulation (WMLES) solutions as the LES grid approaches the direct numerical simulation (DNS) grid. This aspect of WMLES is fundamental but has not been previously investigated or documented. We investigate two types of grid refinements: one where the LES/wall-model matching location is fixed at an off-wall grid point, and another where the matching location is fixed at a specific distance from the wall. In both cases, we refine the LES grid simultaneously in all three Cartesian directions, with grid resolution ranging from typical LES resolution to typical DNS resolution. Our focus is on examining the mean flow and turbulent kinetic energy as the grid refines. While the turbulence statistics consistently converge towards the DNS solution, we observe non-monotonic convergence in the mean flow statistics. We show that improving the grid resolution does not necessarily enhance the accuracy of the mean flow predictions. Specifically, we identify a negative log layer mismatch when the LES/wall-model matching location lies below the logarithmic layer, regardless of grid resolution and matching location. Finally, we demonstrate that the non-monotonic convergence of the mean flow can lead to misleading conclusions from grid convergence studies of WMLES.
Upper Body Joint Angle Calculation and Analysis Using Multiple Inertial Measurement Units
Authors: Freedkin Aaron S. , Ryu Ji-Chul , Hwang Jaejin
Published: February 2024

Understanding how workers move in professions that require unnatural posture can help find solutions to work-related musculoskeletal disorders (WMSDs) that are common in such occupations. IMU (inertial measurement unit)-based measurement is a potential alternative to motion capture systems that are widely used for body posture measurement, but lack portability. This paper applies three sensor fusion algorithms, Madgwick’s filter, Kalman filter, and complementary filter, to estimate joint angles of the shoulder and arm based on the data collected from multiple IMUs. In the implementation of the algorithms, quaternions are used to represent the ideal orientation and avoid singularities. For experiments, three IMUs were placed on the lower arm, upper arm, and upper torso of a subject for two representative motions: reaching up and reaching across a desk. Data from the three IMUs were taken simultaneously and post-processed to estimate the elbow and shoulder joint angles. These estimations were compared with the reference data collected using a motion capture system to determine the overall accuracy for each sensor fusion method. Parameters for each algorithm were optimized to minimize the overall joint angle errors.
An Additively Manufactured Small Footprint Wind Tunnel for Wall Jet and Particle Scavenging Studies
Authors: Wang Jiaxuan , Ul Karim Abrar , Guimarães Tamy , Kunz Robert
Published: February 2024

Subsonic wind tunnels are essential for flow performance quantification and visualization in academic and industrial research. Depending on the application requirements, wind tunnels vary widely in cost and size. In our laboratory, a small footprint wind tunnel was needed for low-speed wall-jet particle scavenging research. We required a test section size of approximately 12in × 12in × 3ft in length, a test section mean velocity of approximately 4–5 m/s, turbulence levels of less than 2%, a re-configurable inlet, and a variable height test-section bottom table to enable wall-jet testing.

An open circuit suction tunnel was additively manufactured at very low cost with a plastic 3D printer. The particular inlet design for our application has a co-flow configuration that includes a separate flow inlet through a blower, enabling the generation of a plane wall jet through a rectangular slot. Additionally, the tunnel is equipped with easily and inexpensively reconfigurable components, inducing an adjustable height build plate, an adjustable angle inlet flow guide plate, a variable speed axial fan, and a diffuser with an embedded filter to remove scavenged metal powder and provide pressure drop. The design incorporates a conventional contraction section with a bell mouth and honeycomb to minimize free stream turbulence and improve flow uniformity in the test section.

The total cost of the tunnel was under $1000. The design detail of each wind tunnel part and its construction is presented in this work. Additively manufactured components enable an easily reconfigurable facility. It is hoped that our success with this effort may inspire others to design and build such test facilities using inexpensive commercial 3D printers.
Primary and Secondary Datum Planes Using Constrained Least Squares As An Efficient, Robust Solution for Standardization
Authors: Shakarji Craig M. , Srinivasan Vijay
Published: February 2024

Datum planes based on a constrained least-squares fit are being adopted in US and ISO standards. Some reasons for the adoption are presented here. In particular, the advantages of this definition over the current definition in ISO 5459 is highlighted. Further, the contrast between the constrained least-squares and the so-called “shifted least squares” is brought out as there is widespread confusion between the two. The handling of secondary datum planes is not a settled matter, and this document explains three candidates for ways to define the secondary datum. The authors show why that of the three, the method that reduces the secondary planar datum problem into a two-dimensional problem is preferred. But up until now, a unsolved issue for that method was the question of how to handle cases when the secondary planar datum feature is not orthogonal to the primary. One of the significant contributions of this paper is solving that thorny case in a straightforward manner, thus removing any technical limitation to its possible adoption.
Reynolds-Averaged Navier-Stokes CFD Simulation of High-Speed Boundary Layers
Authors: Tullis Michael , Walters D. Keith
Published: February 2024

This paper presents an investigation of Reynolds-averaged Navier-Stokes (RANS) turbulence models used in computational fluid dynamics (CFD) simulations of boundary layer flow and heat transfer in high Mach number flows. This study evaluates an industry standard RANS turbulence model (k-ω SST [1]) and a recently proposed modification to that model [2], for prediction of the mean velocity field in selected test cases. The test cases were previously documented by Duan et al. [3], who used direct numerical simulation (DNS) to calculate boundary layer flow of an ideal gas over a flat plate at freestream Mach numbers ranging from 2.5 to 14 and wall to recovery temperature ratios of 0.18 to 1. Boundary layer profiles were evaluated at two streamwise locations, one where the boundary layer height matched the DNS data and the second where the wall shear stress matched DNS data. Results show that the accuracy of RANS models degrades for high-speed regimes compared to incompressible or subsonic flow but that the compressibility correction factor [2] improves the results for some of the test cases.
Rime Ice Accretion on an Airfoil Under Different Icing Conditions Using an Eulerian Approach
Authors: Shad Arash , Sherif S. A.
Published: February 2024

This paper presents a numerical approach to simulate rime ice Accretion on the NACA0012 airfoil and examines its spatial and temporal variations under different icing conditions. The simulation uses an Eulerian two-phase model and a dynamic mesh strategy to account for changes in the ice profile and its impact on airflow. All of the main icing modules, including the airflow field, droplet trajectory, icing growth rate, and mesh management, are fully coupled within the same computational framework without using any external tools. The Reynolds Averaged Navier-Stokes conservation equations, along with the energy and continuity equations, are solved to produce the velocity and temperature fields. The model is validated against experimental data and provides acceptable predictions of ice accretion profiles and rates.
Root rot destabilizes the Sanqi rhizosphere core fungal microbiome by reducing the negative connectivity of beneficial microbes
Authors: Wang Baoying , Geng Yuhang , Lin Yulan , Xia Qing , Wei Fugang , Yang Shaozhou , Huang Xinqi , Zhang Jinbo , Cai Zucong , Zhao Jun
Published: February 2024

The stability of microbial communities, especially among core taxa, is essential for supporting plant health. However, the impacts of disease infection on the stability of rhizosphere fungal core microbiome remain largely unexplored. In this study, we delved into the effects of root rot infestation on the community structure, function, network complexity, and stability of Sanqi fungal core microbiomes, employing amplicon sequencing combined with co-occurrence network and cohesion analyses. Our investigation revealed that root rot disease led to a decrease in the α-diversity but an increase in the β-diversity of the Sanqi fungal core microbiomes in the rhizosphere. Notably,
Ilyonectria
,
Plectosphaerella,
and
Fusarium
emerged as indicator species in the rhizosphere core microbiome of root rot-infected Sanqi plants, while
Mortierella
predominated as the dominant biomarker taxa in healthy soils. Additionally, root rot diminished the complexity and modularity of the rhizosphere networks by reducing the metrics associated with nodes, edges, degrees, and modularity. Furthermore, root rot resulted in a reduction in the proportion of negative connections in the network and the negative/positive cohesion of the entire core fungal microbiome. Particularly noteworthy was the observation that root rot infection destabilized the rhizosphere core fungal microbiome by weakening the negative connectivity associated with beneficial agents. Collectively, these results highlight the significance of the negative connectivity of beneficial agents in ensuring the stability of core microbial community.

IMPORTANCE

Root rot disease has been reported as the most devastating disease in the production process of artificial cultivated Sanqi ginseng, which seriously threatens the Sanqi industry. This study provides valuable insights into how root rot influences microbial relationships within the community. These findings open up opportunities for disease prevention and the promotion of plant health by regulating microbial interactions. In summary, the research sheds light on the ecological consequences of root rot on rhizosphere fungal microbiomes and offers potential strategies for managing soil-borne diseases and enhancing plant health.
Rapid, high-throughput, cost-effective whole-genome sequencing of SARS-CoV-2 using a condensed library preparation of the Illumina DNA Prep kit
Authors: Hickman Rebecca , Nguyen Jason , Lee Tracy D. , Tyson John R. , Azana Robert , Tsang Frankie , Hoang Linda , Prystajecky Natalie A.
Published: February 2024

The ongoing COVID-19 pandemic necessitates cost-effective, high-throughput, and timely whole-genome sequencing (WGS) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viruses for outbreak investigations, identifying variants of concern (VoC), characterizing vaccine breakthrough infections, and public health surveillance. In addition, the enormous demand for WGS on supply chains and the resulting shortages of laboratory supplies necessitated the use of low-reagent and low-consumable methods. Here, we report an optimized library preparation method (the BCCDC cutdown method) that can be used in a high-throughput scenario, where one technologist can perform 576 library preparations (6 plates of 96 samples) over the course of one 8-hour shift. The same protocol can also be used in a rapid turnaround time scenario, from primary samples (up to 96 samples) to loading on a sequencer in an 8-hour shift. This new method uses Freed et al.’s 1,200 bp primer sets (Biol Methods Protoc 5:bpaa014, 2020,
https://doi.org/10.1093/biomethods/bpaa014
) and a modified and condensed Illumina DNA Prep workflow (Illumina, CA, USA). Compared to the original protocol, the application of this new method using hundreds of clinical specimens demonstrated equivalent results to the full-length DNA Prep workflow at 45% of the cost, 15% of consumables required (such as pipet tips), 25% of manual hands-on time, and 15% of on-instrument time if performing on a liquid handler, with no compromise in sequence quality. Results demonstrate that this new method is a rapid, simple, cost-effective, and high-quality SARS-CoV-2 WGS protocol.

IMPORTANCE

Sequencing has played an invaluable role in the response to the COVID-19 pandemic. Ongoing work in this area, however, demands optimization of laboratory workflow to increase sequencing capacity, improve turnaround time, and reduce cost without compromising sequence quality. This report describes an optimized DNA library preparation method for improved whole-genome sequencing of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pathogen. The workflow advantages summarized here include significant time, cost, and consumable savings, which suggest that this new method is an efficient, scalable, and pragmatic alternative for SARS-CoV-2 whole-genome sequencing.
Rickettsia
transmission from whitefly to plants benefits herbivore insects but is detrimental to fungal and viral pathogens
Authors: Shi Pei-Qiong , Wang Lei , Chen Xin-Yi , Wang Kai , Wu Qing-Jun , Turlings Ted C. J. , Zhang Peng-Jun , Qiu Bao-Li
Published: February 2024

Bacterial endosymbionts play important roles in the life histories of herbivorous insects by impacting their development, survival, reproduction, and stress tolerance. How endosymbionts may affect the interactions between plants and insect herbivores is still largely unclear. Here, we show that endosymbiotic
Rickettsia belli
can provide mutual benefits also outside of their hosts when the sap-sucking whitefly
Bemisia tabaci
transmits them to plants. This transmission facilitates the spread of
Rickettsia
but is shown to also enhance the performance of the whitefly and co-infesting caterpillars. In contrast,
Rickettsia
infection enhanced plant resistance to several pathogens. Inside the plants,
Rickettsia
triggers the expression of salicylic acid-related genes and the two pathogen-resistance genes
TGA 2.1
and
VRP
, whereas they repressed genes of the jasmonic acid pathway. Performance experiments using wild type and mutant tomato plants confirmed that
Rickettsia
enhances the plants’ suitability for insect herbivores but makes them more resistant to fungal and viral pathogens. Our results imply that endosymbiotic
Rickettsia
of phloem-feeding insects affects plant defenses in a manner that facilitates their spread and transmission. This novel insight into how insects can exploit endosymbionts to manipulate plant defenses also opens possibilities to interfere with their ability to do so as a crop protection strategy.

IMPORTANCE

Most insects are associated with symbiotic bacteria in nature. These symbionts play important roles in the life histories of herbivorous insects by impacting their development, survival, reproduction as well as stress tolerance.
Rickettsia
is one important symbiont to the agricultural pest whitefly
Bemisia tabaci
. Here, for the first time, we revealed that the persistence of
Rickettsia
symbionts in tomato leaves significantly changed the defense pattern of tomato plants. These changes benefit both sap-feeding and leaf-chewing herbivore insects, such as increasing the fecundity of whitefly adults, enhancing the growth and development of the noctuid
Spodoptera litura
, but reducing the pathogenicity of
Verticillium
fungi and TYLCV virus to tomato plants distinctively. Our study unraveled a new horizon for the multiple interaction theories among plant-insect-bacterial symbionts.
Complete genome sequences of two
Leuconostoc carnosum
strains: 4010 and AMS1
Authors: Li Ran , Lood Cédric , Takala Timo M. , Andreou Gregory , Saris Per E. J. , Lavigne Rob , Wan Xing
Published: February 2024

Leuconostoc carnosum
is a bacterial species commonly associated with meat spoilage. However, some strains exhibit preservative effects due to bacteriocin production. Here, we report the complete genome sequences for two strains,
L. carnosum
4010 and AMS1. Bacteriocin-related gene clusters were found on the plasmids of both strains.
Photochemical inactivation as an alternative method to produce a whole-cell vaccine for uropathogenic
Escherichia coli
(UPEC)
Authors: Westcott Marlena M. , Morse Alexis E. , Troy Gavin , Blevins Maria , Wierzba Thomas , Sanders John W.
Published: February 2024

Uropathogenic
Escherichia coli
(UPEC) is the primary causative agent of lower urinary tract infection (UTI). UTI presents a serious health risk and has considerable secondary implications including economic burden, recurring episodes, and overuse of antibiotics. A safe and effective vaccine would address this widespread health problem and emerging antibiotic resistance. Killed, whole-cell vaccines have shown limited efficacy to prevent recurrent UTI in human trials. We explored photochemical inactivation with psoralen drugs and UVA light (PUVA), which crosslinks nucleic acid, as an alternative to protein-damaging methods of inactivation to improve whole-cell UTI vaccines. Exposure of UPEC to the psoralen drug AMT and UVA light resulted in a killed but metabolically active (KBMA) state, as reported previously for other PUVA-inactivated bacteria. The immunogenicity of PUVA-UPEC as compared to formalin-inactivated UPEC was compared in mice. Both generated high UPEC-specific serum IgG titers after intramuscular delivery. However, using functional adherence as a measure of surface protein integrity, we found differences in the properties of PUVA- and formalin-inactivated UPEC. Adhesion mediated by Type-1 and P-fimbriae was severely compromised by formalin but was unaffected by PUVA, indicating that PUVA preserved the functional conformation of fimbrial proteins, which are targets of protective immune responses.
In vitro
assays indicated that although they retained metabolic activity, PUVA-UPEC lost virulence properties that could negatively impact vaccine safety. Our results imply the potential for PUVA to improve killed, whole-cell UTI vaccines by generating bacteria that more closely resemble their live, infectious counterparts relative to vaccines generated with protein-damaging methods.

IMPORTANCE

Lower urinary tract infection (UTI), caused primarily by uropathogenic
Escherichia coli
, represents a significant health burden, accounting for 7 million primary care and 1 million emergency room visits annually in the United States. Women and the elderly are especially susceptible and recurrent infection (rUTI) is common in those populations. Lower UTI can lead to life-threatening systemic infection. UTI burden is manifested by healthcare dollars spent (1.5 billion annually), quality of life impact, and resistant strains emerging from antibiotic overuse. A safe and effective vaccine to prevent rUTI would address a substantial healthcare issue. Vaccines comprised of inactivated uropathogenic bacteria have yielded encouraging results in clinical trials but improvements that enhance vaccine performance are needed. To that end, we focused on inactivation methodology and provided data to support photochemical inactivation, which targets nucleic acid, as a promising alternative to conventional protein-damaging inactivation methods to improve whole-cell UTI vaccines.
Statin-induced debilitating weakness and myopathy
Authors: Ademi Besim , Folker Jared , Rothwell W Benjamin
Published: February 2024

A large percentage of the US population is either receiving or should be considered for statin therapy. Whether through primary or secondary prevention for atherosclerotic disease, statins remain one of the mainstay options available to physicians. Myalgias are the most commonly reported side effects, though largely self-limited and subjective in nature. Here, we report a case of drug-related myonecrosis following long-term use of atorvastatin. Prompt recognition of the condition and initiation of treatment is paramount to control the disease’s progression. While high-dose steroids are first line, quick escalation to methotrexate, IVIG or rituximab should be considered in refractory cases. This decision is guided by monitoring of serum markers such as CK and transaminases. The goal is quick normalisation of these enzymes, signalling cessation of underlying muscle necrosis. Patients may never regain full function and treatment can last months to years.
Establishing consensus on nutrition competencies for medicine: a Delphi study
Authors: Lepre Breanna , Mansfield Kylie J , Ray Sumantra , Beck Eleanor J
Published: February 2024

Background

Significant research, regulatory bodies and even governmental resolutions have identified meaningful nutrition education for medical and other healthcare professionals as a priority. Doctors are well placed to provide nutrition care, yet nutrition education in medicine remains inadequate regardless of country, setting, or year of training. There remains a need to establish an accepted benchmark on nutrition competencies for medicine, as without consensus standards there is little likelihood of uniform adoption.

Objective

This study aimed to establish consensus on nutrition competencies using a Delphi process to inform a framework for nutrition education in medicine.

Methods

A three-round modified online Delphi survey of experts in healthcare practice, education and training, and experts by experience (service users) was conducted to provide a comprehensive consensus on nutrition competencies for medical practice.

Results

Fifty-two experts (15.1% response rate) participated in Round 1, 42 completed Round 2 and 47 completed Round 3. Participants included medical professionals, dietitians, academics working in health professions education and policymakers from Australia, New Zealand, the UK and Northern Ireland. Twenty-seven service users (57.5% response rate) completed the Round 1 questionnaire, 19 completed Round 2 and 16 completed Round 3. By consensus, 25 nutrition competencies for medicine were defined. The service user panel identified an additional seven skills and attributes considered important in the receipt of nutrition care. Competencies that achieved consensus broadly fell into themes of team-based care, communication, professionalism (eg, attributes) and health promotion and disease prevention. This informs broad skills that may be taught in a nutrition context but could be included in other domains.

Conclusions

The findings suggest doctors need the knowledge and skills to consider the findings from nutrition screening and assessment, coordinate nutrition care when an individual may benefit from further assessment or intervention and provide support for advice delivered by other experts as part of a multidisciplinary approach.
Occupational stress and its correlates among healthcare workers of a tertiary level teaching hospital in Kathmandu, Nepal, during COVID-19 pandemic: a cross-sectional study
Authors: Thapa Suchana , Pradhan Pranil Man Singh
Published: February 2024

Background

Healthcare workers experience high job stress, contributing to negative health outcomes and poor patient care. This study aims to assess occupational stress and its associated factors among healthcare workers at a tertiary hospital during COVID-19 pandemic in Kathmandu, Nepal.

Methods

A cross-sectional quantitative study was conducted among doctors and nurses in a tertiary hospital. A self-administered questionnaire was used to collect data from 368 participants. Bivariate and multiple linear regression analysis identified the predictors associated with occupational stress.

Results

The mean occupational stress index score was 149.56±22.01. It was significantly higher among female participants (151.59±19.12 vs 144.2±27.6, p=0.004), married individuals (152.06±19.79 vs 147.01±23.86, p=0.028), those with over 1 year of employment duration (152.17±21.28 vs 145.45±22.60, p=0.004), health workers attending more than four night shift a month (152.30±19.44 vs 135.52±28.45, p<0.001), those working in rotating shift (151.68±21.12 vs 142.17±23.57, p=0.006), those working 48 hours or more per week (152.39±19.28 vs 145.97±24.66, p=0.005), those lacking support from other staff (157.81±18.70 vs 148.17±22.25, p=0.003) and those who consumed alcohol (152.14±21.25 vs 147.18±22.49, p=0.031). Multiple linear regression revealed associations with employment duration over 1 year (β=0.174, p=0.001), rotating shift (β=−0.106, p=0.006), night shifts (β=0.251, p<0.001), working hours of 48 hours or more per week (β=0.175, p=0.001), lack of support from other staff (β=0.130, p=0.010) and low-wealth quintile (β=0.161, p=0.006).

Conclusion

Occupational stress is associated with employment duration, night shift, rotating shift, working hours, support mechanisms and socioeconomic profile among healthcare workers. There is a crucial need to establish evidence-based actions to prevent occupational stress and promote the overall health of healthcare workers.
Mild elevation of pulmonary vascular resistance predicts mortality regardless of mean pulmonary artery pressure in mild interstitial lung disease
Authors: Sato Tomonori , Furukawa Taiki , Teramachi Ryo , Fukihara Jun , Yamano Yasuhiko , Yokoyama Toshiki , Matsuda Toshiaki , Kataoka Kensuke , Kimura Tomoki , Sakamoto Koji , Ishii Makoto , Kondoh Yasuhiro
Published: February 2024

Background

Pulmonary hypertension (PH) is defined by elevated mean pulmonary arterial pressure (MPAP), and elevated pulmonary vascular resistance (PVR) reflects pulmonary vascular abnormalities. The clinical significance of non-severe PH in patients with various interstitial lung diseases (ILDs) has not been fully elucidated. We aimed to investigate the clinical significance of MPAP and PVR for mortality in patients with newly diagnosed ILD.

Methods

We retrospectively analysed consecutive patients with ILD at initial evaluations that included right heart catheterisation from 2007 to 2018. These patients were classified by MPAP and PVR using the 2022 the European Society of Cardiology (ESC)/the European Respiratory Society (ERS) guidelines for PH. The clinical significance of MPAP and PVR for mortality was analysed.

Results

Among 854 patients, 167 (19.6%) had MPAP>20 mm Hg. The proportion of patients with PVR>2 Wood units (WU) among those with MPAP≤20 mm Hg, 20<MPAP<25 mm Hg, and ≥25 mm Hg were 26.2%, 60.4% and 86.4%, respectively. In Cox proportional hazards analyses with adjustment for ILD–Gender, Age and Physiology Index, PVR but not MPAP was associated with a higher mortality rate (HR 1.37, 95% CI 1.23 to 1.52, p<0.0001; HR 0.98, 95% CI 0.96 to 1.01, p=0.1671, respectively). PVR>2 WU was associated with a higher mortality rate (HR 1.61, 95% CI 1.28 to 2.02, p<0.0001) even in a group with MPAP≤20 mm Hg.

Conclusions

Mild elevation of PVR was associated with a higher mortality rate in patients with newly diagnosed ILD, even in those with MPAP≤20 mm Hg.
Unconstrained Face Recognition Using Infrared Images
Authors: Butt Asif Raza , Ur Rahman Zahid , Ul Haq Anwar , Ahmed Bilal , Manzoor Sajjad
Published: February 2024

Recently, face recognition (FR) has become an important research topic due to increase in video surveillance. However, the surveillance images may have vague non-frontal faces, especially with the unidentifiable face pose or unconstrained environment such as bad illumination and dark environment. As a result, most FR algorithms would not show good performance when they are applied on these images. On the contrary, it is common at surveillance field that only Single Sample per Person (SSPP) is available for identification. In order to resolve such issues, visible spectrum infrared images were used which can work in entirely dark condition without having any light variations. Furthermore, to effectively improve FR for both the low-quality SSPP and unidentifiable pose problem, an approach to synthesize 3D face modeling and pose variations is proposed in this paper. A 2D frontal face image is used to generate a 3D face model. Then several virtual face test images with different poses are synthesized from this model. A well-known Surveillance Camera’s Face (SCface) database is utilized to evaluate the proposed algorithm by using PCA, LDA, KPCA, KFA, RSLDA, LRPP-GRR, deep KNN and DLIB deep learning. The effectiveness of the proposed method is verified through simulations, where increase in average recognition rates up to 10%, 27.69%, 14.62%, 25.38%, 57.46%, 57.43, 37.69% and 63.28%, respectively, for SCface database as observed.
Strain partitioning in the Patagonian Broken Foreland: influence of structural inheritance of early Andean deformation
Authors: García M. , López M. , Bucher J. , Tettamanti M. , Feo R. , D'Elia L. , Franzese J. R.
Published: February 2024

In the context of Andean-type oblique convergence, strain partitioning between thrust and strike-slip tectonics is well documented in the arc region. However, the impact of this configuration in the retroarc remains poorly understood, especially in broken foreland systems where basement structures compartmentalize the retroarc into small intermontane sedimentary basins. The spatiotemporal analysis of tectonic evolution and the role of inherited weaknesses in this area are often debated. This study addresses these uncertainties by integrating geometric and kinematic analyses of tectonic structures within the Sañicó Massif in the North Patagonian foreland. Results reveal two deformational episodes. The initial Late Cretaceous to Paleocene episode represents a contractional deformation phase, with NW–SE shortening direction causing the tectonic inversion of pre-Andean rift depocentres. The second episode records a Neogene transpressional regime with both contractional and strike-slip deformation, with east–west to NE–SW shortening direction, which progressed under reactivation of pre-existing structures and generated new faults. This work demonstrates the Neogene propagation of the strike-slip regime towards the retroarc, defining strain partitioning at various scales and highlighting its interaction with pre-existing structures. These results enhance our understanding of the complex tectonic history in oblique subduction settings, providing significant evidence of the structural inheritance in retroarc systems.