bluuebunny/crossref_metadata_2025 huggingface dataset:
Value‐based care of older people—The impact of an acute outreach service unit on emergency medical service missions: A quasi‐experimental study
Authors: Mäki Lauri J. , Kontunen Perttu J. , Kaartinen Johanna M. , Castrén Maaret K.
Published: October 2023

Background

Transfers to the emergency department can be burdensome for the residents of long‐term residential care facilities (LTRCFs) and often lead to adverse effects. Since March 2019, a nurse‐led acute outreach service unit “Mobile hospital” (in Finnish, Liikkuva sairaala, LiiSa) has been providing on‐site care to LTRCF residents to reduce transfers to the emergency department.

Methods

This study compares the numbers and acuities of emergency medical service (EMS) missions carried out in the LTRCFs of Espoo and Kauniainen during two six‐month periods: before the implementation of LiiSa and with LiiSa in use. In Finland, EMS missions are divided into four categories (A–D), with category A missions being the most urgent. These categories were used to investigate the impact on mission acuities.

Results

Due to the implementation of LiiSa, the number of EMS missions decreased by 16.8% (95% confidence interval 10.6%–22.6%, p < 0.001), the number of category D missions by 19.8% (7.1%–30.8%, p = 0.003) and the number of category C missions by 30.3% (17.3%–41.3%, p < 0.001). Changes in the numbers of category A and B missions were not statistically significant.

Conclusions

LiiSa helped to avoid many transfers of frail LTRCF patients to the emergency department, and it did not hinder the care of patients with true emergencies by EMSs.
A clumped isotope diagenetic framework for the Ediacaran dolomites: Insights to fabric‐specific geochemical variabilities
Authors: Lu Chaojin , Koeshidayatullah Ardiansyah , Li Fei , Cui Huan , Zou Huayao , Swart Peter K.
Published: October 2023

While marine dolomites formed under near surface conditions have been considered to be potentially reliable archives of past oceanic conditions, this interpretation comes with significant challenges because diagenetic alteration frequently produces diverse fabrics with large geochemical variability. It has been suggested that the Ediacaran dolomites in South China (Hamajing Member, Dengying Formation) recorded the oceanic conditions present at the time they formed, yet these dolomites are composed of five different fabrics (stromatolitic, micritic, oolitic, saddle dolomites and fibrous–radial dolomite cements) and show large variations in multiple geochemical isotope proxies (carbon, oxygen, clumped, magnesium and the sulphur of carbonate‐associated sulphate). This study establishes a paragenetic sequence for these dolomites by combining the clumped and the oxygen isotopic compositions, thereby assessing whether they are geochemically representative of the original seawater. Using this diagenetic framework, the micritic and stromatolitic dolomites show a closed‐system behaviour (low water–rock ratios; <0.3) and are largely resistant to the hydrothermal alteration during late diagenesis. In contrast, the ooid and cement fabrics have been affected by the hydrothermal fluid precipitating saddle dolomite in the open‐system condition with the high stimulated water–rock ratios (>1). Furthermore, in a closed‐system environment, the elevated δ24Mg and δ34S values in the stromatolitic dolomite reflect the isotopic Rayleigh fractionation that enriches the 26Mg and 34S through rock‐buffered recrystallization, coupled with microbial sulphate reduction. These results demonstrate that the complex signals in early marine dolomite should be carefully evaluated when used as a palaeoproxy.
Foreign direct investment (FDI) and environmental quality: Is greenfield FDI greener than mergers and acquisitions FDI?
Authors: Ly‐My Dung , Le Thai‐Ha , Park Donghyun
Published: October 2023

Environmental sustainability is a key objective of sustainable development. In this connection, there are growing concerns about the environmental impact of foreign direct investment (FDI), even though it is a potentially powerful engine of growth and development in developing countries. In this study, we empirically examine and compare the environmental impact of two different types of FDI, namely greenfield FDI, and mergers and acquisitions (M&A) FDI. Using data from 91 countries in 2005–2020, we find significant differences in the environmental effects of the two different types of FDI. In particular, our empirical results show that greenfield FDI is more harmful to the environment of host countries than M&A FDI. In addition, FDI from emerging markets and developing countries tends to be more harmful to the environment than FDI from developed countries.
Practical Ductile Fracture Criterion Model for Metallic Aerospace Structure Static Strength Evaluations
Authors: Yoshida Tsutomu , Ishida Takuya
Published: October 2023

A practical ductile fracture criterion model is developed, which is well suited for the aerospace structure static strength evaluations using detailed finite element analysis. The model is based on the classical Coulomb-Mohr fracture criterion and extended to handle strength anisotropy commonly present in aerospace structural metal materials through the application of stress linear transformation.

The resulting model (TCM: Transformed Coulomb-Mohr model) employs the model parameter identification procedure which utilizes the well-established statistically based material allowable database like MMPDS. Therefore it is relatively easy to establish a MMPDS-compatible TCM model database covering wide range of aerospace structural materials, which makes it usable for the real-world large scale airframe development projects.

To demonstrate the ductile fracture predictive capability of the TCM model, static strength tests for several structural elements are conducted and evaluated. Comparison of TCM model predictions against the ones by two other approaches, namely traditional design chart methods, and naive FE-based evaluation utilizing von Mises stress and Ftu, clearly shows the superior capability of the TCM model approach.
Post-Buckling Analysis of Stringer-Reinforced Composite Wing Panel by Classical and CUF-Based Finite Elements and Effect of Material and Geometrical Uncertainties
Authors: Cabral Pedro H. , Do Prado Alex P. , Pagani Alfonso , Augello Riccardo , Carrera Erasmo
Published: October 2023

The design of reinforced composite aerospace structures and the choice of safety margins are strongly affected by our predictive capability. The analysis of buckling and many other failure mechanisms require the use of mathematical models able to capture 3D complex internal stress states, which is a major concern in composite laminates and represents a challenge of today structural simulations. In this work, a detailed model to characterize the post-buckling behaviour and the stress state of a stringer-reinforced composite wing panel subjected to uniform compression is proposed. The model under consideration has layerwise capabilities and is based on the Carrera Unified Formulation (CUF). According to CUF, refined structural theories can be formulated automatically as a generalization of the three-dimensional equilibrium equations and by making use of arbitrary expansion of the primary unknowns, which can be either distributed along 1D (CUF beam models) or 2D (CUF plate models) supports.

Depending on the choice of the expansion functions, low- to high-order structural theories can be developed in a unified manner. Particular attention is focused on the effect of material and geometric uncertainties on the characterization of the limit load, bifurcations, post-buckling and failure. The numerical results clearly show the advantages of the proposed method and provide good confidence for further experimental testing to justify the use of opportune models able to predict and mimic the stochastic dispersion.
Characterization of Interlaminar Fracture Energy for Asymmetric Laminates With Residual Thermal Strains
Authors: Giles Andrew , Venkataraman Satchi
Published: October 2023

Hybrid composite laminates or fiber metal laminates (FML’s) with fiber reinforced polymer (FRP) matrix composites reinforced with metal foils have been investigated for improvements in fatigue, impact resistance and bearing strengths. In this study, to measure fracture properties of interface of metal foil with FRP composite lamina, the specimens with laminate layup [012, AF, |SS, AF, 012] were used; where 0 represents a 0-degree IM7/977-3 unidirectional pre preg ply, AF represents 3M™ AF-191 adhesive film, and SS represents a 0.005 inch 304 full hardened stainless-steel layer. The location of the starter crack obtained using a Teflon insert is indicated by “|”.

Although the full laminate is symmetric, the two adherents on either side of the crack plane are not. Further, the presence of the metal (Stainless steel foil) on the surface of one of the adherents leads to warping of the adherents due to the mismatch in the thermal expansion coefficients and asymmetry of the lay-up of the adherent sub-laminates. This paper discusses a method for accounting for composite laminate asymmetry, residual thermal stresses, and various contact conditions over a crack surface to obtain fracture toughness. MATLAB program was developed to determine the necessary equations and calculation steps required for processing fracture toughness, as well as for automating the data reduction process. Utilizing these new calculation methods, estimations of GIIc values from test data with and without thermal corrections for two different adhesive thicknesses were obtained. A comparison showed the corrected method led to 8% to 20% higher GIIc values.
A Compositional Study of Regolith Composites With Carbon Nanotube Additives for Extraterrestrial Construction
Authors: Hoe Andrea J. , Lin Wenhua , Wang Yeqing
Published: October 2023

As extraterrestrial construction becomes an increasingly relevant goal in society, it is crucial to identify materials that balance high mechanical performance and ease of sourcing. One such candidate material, suitable for lunar habitat construction, is lunar regolith in combination with urea. This research aims to develop a novel lunar regolith composite for improved material strength. In this study we explore the relationship between the loading of carbon nanotubes within lunar regolith composites and their resulting modification of mechanical properties and porosity. Previous studies have shown the incorporation of carbon nanotubes in various applications such as fly ash composites, increases mechanical properties of interest for the material. The formulation of the composite material consists of lunar regolith, urea, distilled water, phosphoric acid, and carbon nanotube powder. The results of this study will include an assessment of the compressive strength for specimens containing carbon nanotubes at different weight fractions of 0%, 0.25%, 0.50% and 1.00%. Uniaxial compression tests demonstrate a maximum compressive strength of 5.82 MPa. We were able to achieve a 23% increase in compressive strength with carbon nanotube additives over composites containing no carbon nanotubes. However, space habitats require thorough and repeated testing to protect the lives at stake in these extreme environments. This increase in compressive strength allows the development of such materials and will allow for more freedom within the structural possibilities available in space architecture.
Nonlinear Global/Local Stress and Free-Edge Analysis of Ultra-Thin Composite Deployable Booms
Authors: Augello Riccardo , Pagani Alfonso , Carrera Erasmo
Published: October 2023

The purpose of this work is to propose an innovative global/local approach for the failure onset analysis of deployable composite thin and ultra-thin structures in the nonlinear field. The adoption of this technique allows for the overcoming of the weaknesses related to the commercial calculation codes, which make use of three-dimensional finite elements to capture the local stress field arising within the booms. In this framework, the proposed approach leads to a reduction of computational cost, while keeping a high level of accuracy. This is possible thanks to the Carrera Unified Formulation, which allows for the modeling of higher-order plate elements for the analysis of local critical regions of complex composite assemblies.

In order to show the potentialities of the global/local approach, particular attention is given to the problems that mostly characterize composites, among which those related to free-edge, failure concept and interlaminar continuity of the displacements and shear stresses. The triangular rollable and collapsible boom is considered in this study. The results show a perfect accuracy of the in-plane stress components between the global stress values, evaluated with commercial software, and local distribution evaluated with a refined layerwise model. The description of the out-of-plane components is shown too, along with the failure indeces.
Development of a Bio-Inspired Sweeping Wing Structure by Utilizing the Emerging Materials in Advanced Additive Manufacturing
Authors: Soydas Velda Basak , Peel Larry D.
Published: October 2023

Birds, bats and insects inspired the design of sweeping wing aircraft. Their ability to sweep and fold their wings to sharper angles increases maneuverability and assists in navigating air currents. Aerospace engineers developed the sweeping wing by installing mechanical pivots between wing sections, such as on the F-111, F-14, and MiG-23 fighter aircraft. However, their wing structures require additional heavy components, which decreases reliability, payload capacity and aircraft performance. This conceptual work replaces mechanical parts with lighter, bio-inspired flexible hinges and compliant structures, allowing wing-sweeping up to 60°. The primary objective of this study is to have the skin of an un-swept wing fold at multiple locations into a swept wing with fences, reducing spanwise flow. Mathematical models of a flat wing were developed to create multi-segment rectangular and tapered sweeping wings. Several configurations with three wing segments and segment sweep angles were evaluated. 3D CAD models were developed and 3D printed with flexible, compliant hinges and rigid components. These prototype hinges and sweeping mechanisms held their un-swept and swept shapes in proper configurations without tearing or failure and demonstrated viability. The current work is only for a flat wing. However, future work could expand to a traditional wing cross-section using flexible composites.
Flexural Fatigue Behavior of Sea Water Conditioned Carbon/Epoxy Nanoclay Composites
Authors: Tareq Md. Sarower , Hosur Mahesh , Zainuddin Shaik
Published: October 2023

In this work, the flexural fatigue behavior of carbon fiber reinforced plastic (CFRP) composites with respect to stiffness degradation, fatigue life prediction and 3D damage mode with addition of nanoclay as matrix filler is investigated. Three-point static flexural tests were conducted to measure the elastic modulus and failure strength/deflection of the composites. Load-controlled flexural fatigue tests were performed at different stress levels; 0.9, 0.8, 0.75 and 0.7 times the static strength of the corresponding control and nanophased samples to determine the fatigue life and stiffness degradation, respectively. The fatigue life was reliably predicted by means of combined Weibull and Sigmoidal model. It was found that nanoclay added samples exhibited more than 327% improvement in the mean fatigue life and more than 352% improvement in the predicted fatigue life (Pf = 0.5), compared to the control samples. At 0.7 stress level, all the nanoclay added samples passed the ‘run-out’ fatigue criteria of one million cycles, whereas majority of the control samples failed much earlier. Conditioning (6 months under seawater at ambient temperatures) effect on the fatigue performance of the CFRP samples showed that both control and nanoparticles added samples demonstrated lower fatigue life in comparison with corresponding unconditioned samples.
Nonlinear Model Predictive Control of Urban Air Mobility Aircraft for Vibration Suppression and Trajectory Tracking
Authors: Santos Martins Nunes Jessica , Su Weihua
Published: October 2023

This paper presents the development and simulation of the Nonlinear Model Predictive Controller (NMPC) of a tiltrotor urban air mobility (UAM) aircraft. The free flight of the aircraft is governed by a set of nonlinear rigid-body dynamic equations with multiple tiltrotors and their gyroscopic and inertial effects. As a comparison, a feedback Linear-Quadratic Regulator (LQR) is also designed. The control variables include two rotors‘ spin rates, in addition to the traditional elevator, aileron, and rudder deflections. Both controllers are compared in two cases: level flight for vibration suppression and lateral trajectory path tracking. Even though similar results can be obtained in the vibration suppression with the NMPC and LQR, better performance of the NMPC can be observed in the path-tracking case. Unlike the vibration control case, the nonlinear nature of the aircraft flight dynamics should be accounted for by the controller design to properly track the ever-changing path reference, which is not the case for the LQR. In short, while the NMPC has a higher computational cost, it also demonstrates a much better control performance than the LQR.
The Effect of Oxidation in Environmental Barrier Coatings Subject to Foreign Object Damage
Authors: Hoffman Leland C. , Presby Michael J. , Stokes Jamesa L. , Harder Bryan J. , Salem Jonathan A.
Published: October 2023

Oxidation and foreign object damage (FOD) are two key failure modes for environmental barrier coatings (EBCs). For EBCs with a silicon (Si) bond coat, a thermally grown oxide (TGO) layer forms at the EBC – bond coat interface. The TGO layer is considered the weak interface, and directly influences the life of the EBC. Moreover, FOD has been shown to cause significant subsurface damage resulting in delamination or spallation of the EBC which can occur at the EBC - bond coat interface or the bond coat - substrate interface. The purpose of this work is to investigate the synergistic effects of oxidation and FOD in a ytterbium disilicate (Yb2Si2O7) EBC. FOD testing is conducted on as-deposited and steam oxidized samples at room temperature using a 1.59 mm hardened steel ball projectile. The resulting damage is characterized by optical profilometry and scanning electron microscopy (SEM). Additionally, a quasi-static, mechanical assessment of the EBC bond strength in the presence of a growing TGO is presented.
Effects of Manufacturing Processes on Progressive Damage of Composites
Authors: Meka Sai Krishna , Enos Ryan Scott , Zhang Dianyun
Published: October 2023

The manufacturing processes of composites involve complex and inter-related procedures that span across multiple physics domains and scales. To understand the effects of the manufacturing processes on a composite laminate we perform a progressive damage analysis on the composite. We aim to compare residual stresses that are developed due to the Cure Hardening Instantaneous Linear Elastic (CHILE) model, and residual stresses developed due to a simple temperature drop from the rubbery state to glassy state during the manufacturing of the composite. On the application of mechanical loading after the curing of the composite, we incorporate the smeared crack approach to account for the progressive damage of the composite.
A Combined Finite Element and Machine Learning Approach to Accelerate Calibration and Validation of Numerical Models for Prediction of Failure in Aerospace Composite Parts
Authors: Eskandariyun Amirali , Joseph Ashith , Stere Alexandru , Byar Alan , Fomin Sergey , Kabir Mohammed , Dong John , Zobeiry Navid
Published: October 2023

The need for a large number of costly experimental tests is a major challenge in the certification of composite parts in the aerospace industry. While computational simulation, specifically the finite element method (FEM), can accelerate this process through analysis supported by testing, the time-consuming calibration of composite failure models remains a drawback. This often requires an engineer with years of experience to perform trial-and-error simulations. To address this, an automated machine learning framework has been proposed to simulate and calibrate the failure models of composites in an accelerated and low-cost manner. In this framework, FEM parameters are calibrated using probabilistic machine learning in a step-by-step and targeted approach. The single-edge notch tension (SENT) test was chosen as a case study and simulated explicitly with predefined initial parameters. The result was compared with experiments to calculate the calibration error. Then, Gaussian process regression (GPR) was used in an in-house developed program to automatically select new failure parameters based on initial values and the calibration error in the previous step. The program continues this process until the error becomes negligible. For validation, the calibrated model was used to predict the behavior of a center-notch tension (CNT) test. The presented automated framework provides a robust and reliable calibrated model in a significantly faster manner. It also reduces a substantial amount of computational costs, eliminates the need for high expertise, and saves valuable engineering time.
Truss Topology Optimization With Semidefinite Programming and Parametric Model Order Reduction
Authors: Sanmugadas Varakini , Kapania Rakesh K.
Published: October 2023

The feasibility of a hybrid PMOR-SDP approach, that combines semidefinite programming (SDP) and parametric model order reduction (PMOR) was investigated. When an optimization problem comprises of a linear objective and linear matrix inequality constraints, SDP provides an efficient algorithm for arriving at a globally optimum design. This is achieved by solving a linear systems of equations that simultaneously satisfies the optimality conditions of the primal and dual problems. Weight minimization of a structure subjected to frequency or buckling constraints is amenable to this approach. It is postulated that with the right choice of basis and sufficient reduction in the size of the system matrices defining the problem, the convergence of the SDP problem can be accelerated. To test this idea, the weight minimization of a 200-bar truss, subjected to a frequency constraint, was studied here owing the relative simplicity of the problem. The MOSEK solver was used to solve the linear SDP problem. It was found that the Krylov space containing the second moment provided the best basis set. However, the expected reduction in optimization time was not achieved as this approach did not preserve the sparse nature of the stiffness and mass matrices. Future work will study structure-preserving model order reduction to address this issue.
Effect of Preload on Joint Rotation Constant of Conventional Aerospace Bolted Joints
Authors: Medepalli Varadanam , Kalahasti Kishore Kumar , Popuri Bangarubabu
Published: October 2023

Airframe assembly with axial bolted joints in flange configuration is subjected to combined loading of axial load, bending moment and shear force. Structural Integrity of full-scale airframe assemblies is evaluated by conducting full-scale bend load test and by measurement of Joint Rotation Constant (JRC) at different joints to estimate natural frequencies, mode shapes and global deflections accurately and also to classify the joints. Structural integrity, JRC and class of joints primarily depend on type of joint and its preload. Experiments are carried out on axial bolted joint configurations with Pipe and Airframe sections. Effect of preload on JRC at both joints is studied at different torque levels with increasing bending moment. Reduction in measured JRC is observed with increasing preload at Pipe section as well as Airframe section joints. Measured JRC values at both joints have shown decreasing trend with increasing BM for initial preloads before showing increasing trend for higher preloads. Initially, no variation in measured frequencies of first three modes is observed with increasing preload followed by mild increase before showing no variation again for higher preloads for Airframe section joint. The behavior of JRC at different preloads with increasing bending moment indicates how the modal parameters of the assembly and deflections are expected to behave for various preloads.
Self-Healing of Fatigue Delamination in Thermoset Composites Using Thermoplastic Healants
Authors: Vishe Nilesh J. , Mulani Sameer B. , Roy Samit
Published: October 2023

In this study, fatigue testing under mode-I loading was carried out on double cantilever beam (DCB) specimens, and subsequent healing of the delamination was investigated. Due to the susceptibility of laminated composites to delamination, fatigue delamination is one of the crucial damage modes in laminated composites that may result in catastrophic structural failure. Hence, it is necessary to investigate and quantify the delamination crack growth behavior due to fatigue loading and explore methods to heal the delamination. Therefore, DCB specimens of a carbon fiber-reinforced thermoset polymer (CFRP) composite containing thermoplastic healants were manufactured. The main objective of using thermoplastic healants, i.e., polycaprolactone and shape memory polymer, was to close and then heal the fatigue cracks. In-situ self-healing was achieved by activating macro fiber composite (MFC) actuators bonded to the DCB specimen, where the high-frequency vibration of the actuator provides the heat necessary to close the cracks using thermoplastic healants.
Development of a Test Rig for Improved Estimation of Structural Damping of Wind Turbine Composite Materials
Authors: Brough Euan , Nash David , Kazemi Amiri Abbas Mehrad , Couturier Philippe , Reis Vitor Luiz
Published: October 2023

Material damping affects the vibrational response of composite wind turbine blades, which in turn has an impact on the structural stability and fatigue life of the entire system. Understanding material-level structural damping is crucial for improving the performance and reliability of wind turbines. The present work aims to develop an increased understanding of material-level structural damping and focuses on the development of a rig to reliably quantify energy dissipation properties of candidate wind turbine materials. The novel test rig employs Experimental Modal Analysis (EMA) in a vacuum to improve experimental structural damping characterization of high-modulus materials. The test rig allows for a non-constrained, free-free suspension of a sample which minimizes energy loss mechanisms that can lead to unrepresentative results. Sample excitation methods were also compared, and an automated excitation method was devised. The capabilities of the test rig are presented by the damping extraction of aluminum specimens. The results presented also quantify the component of aerodynamic damping present by comparing EMA with and without the presence of air, for several tests, allowing for the characterization of structural damping.
Stabilization of the tetragonal phase in ZrO2 thin films according to ozone concentration using atomic layer deposition
Authors: Song Seokhwi , Kim Eungju , Kim Kyunghoo , Bae Jangho , Lee Jinho , Jung Chang Hwa , Lim Hanjin , Jeon Hyeongtag
Published: October 2023

In this study, we investigated the crystallographic and electrical properties of ZrO2 thin films prepared by an ozone-based atomic layer deposition process. Cyclopentadienyl tris(dimethylamino) zirconium [CpZr(NMe2)3] was used as the Zr precursor, and O3 was used as the reactant. ZrO2 films were produced using O3 in various concentrations from 100 to 400 g/m3. These thin films were used to fabricate metal–oxide–semiconductor capacitors, whose electrical properties were evaluated and correlated with crystallographic analysis. As the O3 concentration increased, the tetragonal phase of the ZrO2 film stabilized and the dielectric constant improved. However, the leakage current density characteristics concurrently deteriorated due to the high concentration of O3, increasing the number of grain boundaries in the ZrO2 film by increasing crystallinity. Thus, the concentration of O3 can control the number of OH groups of the ZrO2 film, affecting the device characteristics.
Acyl-AcpB, a FabT corepressor in
Streptococcus pyogenes
Authors: Lambert Clara , d'Orfani Alice , Gaillard Marine , Zhang Qiufen , Gloux Karine , Poyart Claire , Fouet Agnes
Published: October 2023

Membranes are a universal barrier to all cells. Phospholipids, essential bacterial membrane components, are composed of a polar head and apolar fatty acid (FA) chains. Most bacterial FAs are synthesized by the Type II FA synthesis pathway (FASII). In Streptococcaceae, Enterococci, and
Lactococcus lactis
, a unique feedback mechanism controls the FASII gene expression. FabT, encoded in the FASII main locus, is the repressor, and it is activated by long-chain acyl-acyl carrier protein (acyl-ACP). Many Streptococci,
Enterococcus faecalis
, but not
L. lactis
, possess two ACPs. The AcpA-encoding gene is within the FASII locus and is coregulated with the FASII genes. Acyl-AcpA is the end product of FASII. The AcpB-encoding gene is in operon with
plsX
encoding an acyl-ACP:phosphate acyltransferase. The role of acyl-AcpB as FabT corepressor is controversial.
Streptococcus pyogenes
, which causes a wide variety of diseases ranging from mild non-invasive to severe invasive infections, possesses AcpB. In this study, by comparing the expression of FabT-controlled genes in an
acpB
-deleted mutant with those in a wild-type and in a
fabT
mutant strain, grown in the presence or absence of exogenous FAs, we show that AcpB is the
S. pyogenes
FabT main corepressor. Its deletion impacts membrane FA composition and bacterial adhesion to eucaryotic cells, highlighting the importance of FASII control.

Importance

Membrane composition is crucial for bacterial growth or interaction with the environment. Bacteria synthesize fatty acids (FAs), membrane major constituents, via the Type II FAS (FASII) pathway. Streptococci control the expression of the FASII genes via a transcriptional repressor, FabT, with acyl-acyl carrier proteins (ACPs) as corepressor.
Streptococcus pyogenes
that causes a wide variety of diseases ranging from mild non-invasive to severe invasive infections possesses two ACPs.
acpA
, but not
acpB
, is a FASII gene. In this study, we show that acyl-AcpBs are FabT main corepressors. Also, AcpB deletion has consequences on the membrane FA composition and bacterial adhesion to host cells. In addition to highlighting the importance of FASII control in the presence of exogeneous FAs for the adaptation of bacteria to their environment, our data indicate that FASII gene repression is mediated by a corepressor whose gene expression is not repressed in the presence of exogenous FAs.
SERPINB1 promotes Senecavirus A replication by degrading IKBKE and regulating the IFN pathway via autophagy
Authors: Yan Junfang , Gao Yanni , Bai Juan , Li Jian , Li Minjing , Liu Xing , Jiang Ping
Published: October 2023

Innate immunity and autophagy play crucial roles in regulating Senecavirus A (SVA) replication. However, the reciprocal coordination between these systems during virus infection is not understood. Our results show that SERPINB1, a member of the SERPINB family, facilitates SVA replication. Mechanistically, ectopic expression of SERPINB1 increases the degradation of IκB kinase epsilon (IKBKE) through the ubiquitin-proteasome pathway. The removal of IKBKE antagonizes the IKBKE-mediated inhibition of proliferation that normally generates an interferon response via the AKT/mTOR/BECN1 axis. We conclude that SERPINB1 promotes SVA replication by eliciting autophagy-triggered innate inhibition, suggesting that SERPINB1 is a potential therapeutic target for the control of viral infection.

IMPORTANCE

Senecavirus A (SVA) is an emerging picornavirus associated with vesicular disease, which wide spreads around the world. It has evolved multiple strategies to evade host immune surveillance. The mechanism and pathogenesis of the virus infection remain unclear. In this study, we show that SERPINB1, a member of the SERPINB family, promotes SVA replication, and regulates both innate immunity and the autophagy pathway. SERPINB1 catalyzes K48-linked polyubiquitination of IκB kinase epsilon (IKBKE) and degrades IKBKE through the proteasome pathway. Inhibition of IKBKE expression by SERPINB1 induces autophagy to decrease type I interferon signaling, and ultimately promotes SVA proliferation. These results provide importantly the theoretical basis of SVA replication and pathogenesis. SERPINB1 could be a potential therapeutic target for the control of viral infection.
Major data analysis errors invalidate cancer microbiome findings
Authors: Gihawi Abraham , Ge Yuchen , Lu Jennifer , Puiu Daniela , Xu Amanda , Cooper Colin S. , Brewer Daniel S. , Pertea Mihaela , Salzberg Steven L.
Published: October 2023

We re-analyzed the data from a recent large-scale study that reported strong correlations between DNA signatures of microbial organisms and 33 different cancer types and that created machine-learning predictors with near-perfect accuracy at distinguishing among cancers. We found at least two fundamental flaws in the reported data and in the methods: (i) errors in the genome database and the associated computational methods led to millions of false-positive findings of bacterial reads across all samples, largely because most of the sequences identified as bacteria were instead human; and (ii) errors in the transformation of the raw data created an artificial signature, even for microbes with no reads detected, tagging each tumor type with a distinct signal that the machine-learning programs then used to create an apparently accurate classifier. Each of these problems invalidates the results, leading to the conclusion that the microbiome-based classifiers for identifying cancer presented in the study are entirely wrong. These flaws have subsequently affected more than a dozen additional published studies that used the same data and whose results are likely invalid as well.

IMPORTANCE

Recent reports showing that human cancers have a distinctive microbiome have led to a flurry of papers describing microbial signatures of different cancer types. Many of these reports are based on flawed data that, upon re-analysis, completely overturns the original findings. The re-analysis conducted here shows that most of the microbes originally reported as associated with cancer were not present at all in the samples. The original report of a cancer microbiome and more than a dozen follow-up studies are, therefore, likely to be invalid.
Open peer review, pros and cons from the perspective of an early career researcher
Authors: Henriquez Tania
Published: October 2023

Peer review is considered by many to be a fundamental component of scientific publishing. In this context, open peer review (OPR) has gained popularity in recent years as a tool to increase transparency, rigor, and inclusivity in research. But how does OPR really affect the review process? How does OPR impact specific groups, such as early career researchers? This editorial explores and discusses these aspects as well as some suggested actions for journals.
M13KO7 bacteriophage enables Potato Virus Y detection
Authors: Seo Haneul , Cho Sang-Ho , Vo Thuy T. B. , Lee Ahlim , Cho Sungrae , Kang Sol , Kil Eui-Joon , Byun Hee-Seong , Lee Mi-Gi , Kwon Myung-Hee , Chung Woo-Jae , Lee Young-Gyu , Lee Sukchan
Published: October 2023

Potato virus Y
(PVY) is one of the foremost plant viruses affecting potato plants and production. Many diagnostic and detection techniques are available to detect and prevent the spread of this virus. Serological analyses, such as enzyme-linked immunosorbent assay (ELISA), are widely used in laboratories as well as in the field. In addition, recently, serological methods using whole or recombinant antibodies have been developed. However, these antibodies are unstable under certain chemical conditions and can be easily degraded by exposure to enzymes. M13KO7, a derivative of bacteriophage M13, with a filamentous structure similar to PVY, was used for antibody screening. We found that PVY and “bald” M13KO7 had binding activity similar to that of antigen-antibody in ELISA analyses. The binding interactions between PVY and M13KO7 were highly specific. A new method for detecting PVY using ELISA analysis with M13KO7 was developed in this study. These results provide new insights into two virus-binding interactions and novel systems for the detection of plant viruses.

IMPORTANCE

In this study, we confirmed the binding of M13KO7 to
Potato virus Y
(PVY) using enzyme-linked immunosorbent assay. M13KO7 is a “bald” bacteriophage in which no recombinant antibody is displayed. M13KO7 is easy to propagate by using
Escherichia coli
, making this method more reasonable in economic perspective. Based on this study, we suggest that M13KO7 detection system has applicability as a novel biological tool for the detection of PVY
Effect of “Refraction” of Magnetic Domain Boundaries at Electrical Inhomogeneities
Authors: Podkletnova A. A. , Kolyushenkov M. A. , Myasnikov N. V. , Nikolaeva E. P. , Kaminskiy A. S. , Nikolaev A. V. , Pyatakov A. P.
Published: October 2023

A magnetoelectric effect, which manifests itself as a “refraction” of domain walls at the location of an electrode deposited on the surface of an iron garnet film, is studied. The “refractive index” depends on the electric voltage applied to the electrode and varies from 0.6 to 1.2. An electrically induced change in the surface energy of a domain wall due to an inhomogeneous magnetoelectric coupling is suggested as the mechanism of this effect.
Acute monoarticular hip joint pseudogout masquerading as septic arthritis
Authors: Bichay Mina Samir Marzouk , Ward Harry , Abukar Amin Abdurahman , Gadikoppula Srinivas
Published: October 2023

Monoarticular pseudogout of the hip joint is rare and to the best of our knowledge only four other cases exist in the literature. We present a case of primary monoarticular pseudogout affecting the right hip in a patient in his 50s. The diagnosis was confirmed through ultrasound-guided synovial fluid aspiration and crystal analysis. The patient was treated conservatively with analgesia and after hip joint aspiration resulted in dramatic symptomatic resolution. Acute attack of pseudogout is a rare cause of acute hip pain. The clinical features may mimic hip joint septic arthritis and should be considered in the differential diagnosis of any presentation of acute joint pain. Diagnosis is important to avoid unnecessary medical and surgical intervention reducing hospital stay.
Pericardial effusion and systemic capillary leak syndrome late post-SARS-CoV-2 vaccination
Authors: Yang Cathevine , Tsang Michael YC , Zypchen Leslie N , Luong Christina
Published: October 2023

We report an interesting case of pericardial effusion associated with idiopathic systemic capillary leak syndrome (ISCLS) following administration of SARS-CoV-2 vaccine. This patient initially presented with dyspnoea and chest pain, with non-pitting oedema and clear lung fields. The diagnosis of ISCLS was made based on the clinical syndrome and laboratory evidence of polycythaemia and hypoalbuminaemia. An enlarging pericardial effusion was diagnosed on transthoracic echocardiogram. Daily point-of-care ultrasound (POCUS)-guided volume management and serial transthoracic echocardiograms contributed to avoidance of refractory shock, cardiac tamponade and critical care admission.
Risk factors and biomarkers for post-tuberculosis lung damage in a Chinese cohort of male smokers and non-smokers: protocol for a prospective observational study
Authors: Gai Xiaoyan , Cao Wenli , Rao Yafei , Zeng Lin , Xu Wei , Wu Haifeng , Li Gen , Sun Yongchang
Published: October 2023

Introduction

Post-tuberculosis lung damage (PTLD) refers to the residual pulmonary impairment following the completion of antituberculosis (TB) therapy, characterised by persistent respiratory symptoms and abnormal pulmonary function. The risk factors and biomarkers for PTLD have been scarcely investigated. More importantly, whether and to what extent cigarette smoking is involved in PTLD remain to be known.

Methods and analysis

This prospective observational study will enrol 400 male smoking or non-smoking patients aged 25–65 years, with newly confirmed active TB between 2022 and 2024, from the Department of Respiratory and Critical Care Medicine at Peking University Third Hospital and the Tuberculosis Department at Beijing Geriatric Hospital. Because females rarely smoke in China, we will enrol only males in this study. Demographic data, smoking history and amount, clinical symptoms, lung function, and chest CT findings will be prospectively collected. Respiratory questionnaires, lung function measurements and chest CT examinations will be performed immediately after, and 1 year, 2 years and 3 years after the completion of TB treatment. Peripheral blood samples will be obtained at baseline and at the end of anti-TB therapy, and a Luminex xMAP-based multiplex immunoassay will be used to measure inflammatory mediators and cytokines in serum. The collected data will be analysed to determine the incidence and factors/biomarkers of PTLD according to smoking status.

Ethics and dissemination

The study was approved by the Ethics Committee of Peking University Third Hospital (approval number: (2022)271-03; approval date: 8 June 2022). The research results will be disseminated through scientific and medical conferences and will be published in an academic journal.

Trial registration number

NCT04966052.
Did the UK’s COVID-19 restrictions during 2020 have a differential impact on the well-being of the LGBQ+ population: a mixed methods study
Authors: Hope Vivian D , Timpson Hannah , Porcellato Lorna , Brett Caroline E , Harrison Rebecca , Hunt Anna , Bigland Charlotte , Leavey Conan , Hay Gordon , Saini Pooja
Published: October 2023

Objective

The social distancing measures governments implemented in response to the COVID-19 pandemic have had substantial impacts. For some communities, these impacts will be disproportionate, with those communities experiencing inequalities, marginalisation or discrimination facing specific challenges. Lesbian, gay, bisexual, queer and allied (LGBQ+) communities experience a range of well-being inequalities that may have been impacted by the pandemic. The study aimed to assess the comparative impact of the UK’s response to COVID-19 on LGBQ+ communities.

Design

A mixed-method explanatory sequential study of the general population using a cross-sectional online survey and semistructured interviews.

Setting

Community, North West of England.

Participants

Adults aged 18 years and over; 1540 participated in the survey (192, 12%, LGBQ+) with 49 undergoing semistructured interviews (15 LGBQ+) during spring and summer of 2020.

Results

Survey findings indicated that LGBQ+ people experienced similar positive and negative impacts to the rest of the population, but some negative impacts were more marked among the LGBQ+ community. LGBQ+ participants were more likely to disagree that ‘the government considered the impact on people like you’ when preparing guidance. They were significantly more likely to report being unable to access sufficient food and required medication, eating less healthily, exercising less regularly, experiencing poorer quality sleep and taking more pain medicine than usual. Interview data supported these differences; isolation, being unable to access social networks and concerns about health were commonly discussed by the LGBQ+ participants. Positive impacts, including better work–life balance, were similar across both groups.

Conclusions

The findings indicate LGBQ+ communities’ wellbeing inequalities have been compounded by the social distancing restrictions, for example, by impacts on social networks increasing loneliness. Preparedness planning for future pandemics should include equality impact assessments for potential interventions.
Prevalence of non-communicable diseases and risk factors of pre-eclampsia/eclampsia in four local government areas in Nigeria: a cross-sectional study
Authors: Ogboye Ayoposi , Akpakli Jonas Kofi , Iwuala Amira , Etuk Imo , Njoku Kendra , Jackson Stodia , Okoli Ugo , Hill Kathleen , Omoera Victoria , Oludara Folashade , Ekong Iniobong , Mobisson Nneka
Published: October 2023

Objectives

To assess the prevalence of non-communicable diseases (NCDs) and risk factors associated with pre-eclampsia and eclampsia (PE/E) in women of reproductive age (WRA) in Nigeria.

Design

A cross-sectional survey was administered to the entire study population. In the point-of-care testing, physical and biochemical measurements were taken in a subset of the participants.

Setting

The study was conducted in the Ikorodu and Alimosho local government areas (LGAs) in Lagos and the Abuja Municipal Area Council and Bwari LGAs in the Federal Capital Territory.

Participants

Systematic random sampling was used to randomly select and recruit 639 WRA (aged 18–49 years) between May 2019 and June 2019.

Outcome measures

Prevalence of select NCDs (hypertension or raised blood pressure, diabetes or raised blood sugar levels, anaemia, truncal obesity and overweight/obesity) and risk factors associated with PE/E (physical activity, fruit and vegetable consumption, alcohol consumption and smoking).

Results

The prevalence of raised blood pressure measured among the WRA was 36.0% (95% CI 31.3% to 40.9%). Approximately 10% (95% CI 7.2% to 13.4%) of participants had raised blood sugar levels. About 19.0% (95% CI 15.3% to 23.2%) of the women had moderate or severe anaemia. Excluding WRA who were pregnant, 51.9% (95% CI 45.7% to 58.0%) of the women were either overweight or obese based on their body mass index. Approximately 58.8% (95% CI 53.8% to 63.6%) of WRA surveyed reported three to five risk factors for developing NCDs and PE/E in future pregnancies.

Conclusions

The study identified a high prevalence of NCDs and associated PE/E risk factors in surveyed women, signifying the importance of early detection and intervention for modifiable NCD and associated PE/E risk factors in WRA. Further research is necessary to assess the national prevalence of NCDs.
Longitudinal assessment of bacterial vaginosis prior to and during incident pregnancy: an observational study in Kenyan adolescent girls and young women
Authors: Oluoch Lynda , Tapia Kenneth , Kiptinness Catherine , Casmir Edinah , Maina Stephen Gakuo , Makena L , Selke Stacy , Wang Melody , Chohan Bhavna , Sycuro Laura , Wald Anna , Ngure Kenneth , Mugo Nelly , Roxby Alison
Published: October 2023

Objective

To determine bacterial vaginosis (BV) status at multiple time points among adolescent girls and young women (AGYW) and assess the impact of pregnancy on their BV status.

Design

Longitudinal cohort study.

Setting

Thika, Kenya.

Participants

AGYW aged 16–20 years enrolled prior to first sex or reporting only a single lifetime partner.

Main outcome measures

The primary outcome was relative risk (RR) of BV during pregnancy compared with before pregnancy by analysing longitudinal trends in BV over time. BV risk was estimated using Poisson regression models.

Results

A total of 121 AGYW became pregnant in the parent cohort and had BV results before, during or after pregnancy. Point prevalence of BV was 11.0% at visits >12 months pre-pregnancy, 13.0% at 3–12 months pre-pregnancy, 22.1% at <3 months pre-pregnancy and 13.4% during pregnancy. Compared with visits during pregnancy, RR of BV was 1.65 (95% CI: 1.00 to 2.71; p=0.05) at visits <3 months pre-pregnancy, 0.97 (95% CI: 0.62 to 1.52; p=0.90) at visits 3–12 months pre-pregnancy and 0.82 (95% CI: 0.44 to 1.53; p=0.53) at visits 12 months pre-pregnancy. An adjusted analysis including age, income, residence, date of first sex, recent sexual activity and positive sexually transmitted infection test resulted in small changes in risk estimates, with adjusted RR of BV of 1.66 (95% CI: 1.04 to 2.67; p=0.04) at visits <3 months pre-pregnancy compared with visits during pregnancy.

Conclusions

BV risk during pregnancy was lower than during the immediate pre-pregnancy period. Hormonal changes in pregnancy may reduce BV.