bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of hollow glass microspheres on transverse properties of carbon fiber reinforced epoxy composites
Authors: Tejasvi K. , Sharma Annu , Ranga K. V. S. , Gurusideswar S. , Sundar Singh P.
Published: August 2024

Hollow glass microsphere (HGM)—based composites are gaining popularity in materials research due to their ability in altering material characteristics drastically. The current study investigates HGMs filled carbon fiber reinforced epoxy (CE) composites on transverse properties, aiming for aerospace and defense applications mainly in composite pressure vessels. Unidirectional laminates of Carbon/Epoxy with varying HGM percentages (0.2, 0.4, 0.6, 0.8, 1.0 wt. %) were wounded onto a flat‐plate mandrel using a 4‐axis filament winder, along with a baseline sample without HGM for comparison. The glass transition temperature (Tg) and thermal stability were analyzed by carrying out dynamic mechanical analysis and thermogravimetric analysis. The fracture mechanism of the samples loaded under tension was investigated using FESEM. Experimental results indicate reduction in density with increase in HGM content, up to 0.4% HGM there is increase in transverse tensile strength of 25% compared to baseline and further increase in HGM content, decrease trend is observed. 30% decrease in transverse compressive strength is observed compared from baseline to 1.0 wt. % of HGM. No significant change was noticed in the thermal stability and Tg on introduction of HGM. Microscopy images of fractured samples revealed effective physical interaction and dispersion of the HGM within the matrix.

Highlights

Transverse mechanical properties are tested to know the influence of HGM filler on filament wound composites.

Density of the composite decreases with increase in HGM content.

Thermal stability and Tg shows less change on introduction of HGM in composites.
Stability study of Nepeta cataria iridoids analyzed by LC/MS
Authors: Lockhart Anthony , Simon James Edward , Wu Qingli
Published: August 2024

Introduction

Catnip (Nepeta cataria, L.) has well‐documented applications in arthropod repellency because of its bioactive iridoids. Long‐term stability of nepetalactones and other iridoids in N. cataria are needed to develop as effective pest repellents.

Objectives

The present work intends to measure iridoid concentration over time in biomass, plant extracts, and extract solution while identifying degradative byproducts under different storage conditions.

Methodology

Samples of desiccated biomass, ethanol extract, and extract in ethanol solution were stored in ambient light or darkness. Through UHPLC‐QTOF/MS or UHPLC‐QQQ/MS, the concentration of Z,E‐nepetalactone, E,Z‐nepetalactone, nepetalic acid, and dihydronepetalactone were examined over 2 years and statistically analyzed for determination of best storage practices. Degradation kinetics were applied to each analyte using graphical estimation. With targeted formula searching, degradative byproducts were identified and quantified.

Results

Light exposure caused significant decreases in E,Z‐nepetalactone concentration in all sample types, while having no effect on Z,E‐nepetalactone as it decayed more rapidly. Extract samples lost nepetalactone content faster than biomass or extract solution. Dihydronepetalactone levels were low, but never declined over 2 years. Nepetalic acid increased over some periods, depending on sample type, indicating a relationship between the acid and nepetalactone. Four degradative byproducts—nepetonic acid, dehydronepetalactone, an anhydride, and an ethanolic ester—were identified, with variable responses to light exposure.

Conclusions

Protecting catnip products from light is necessary to preserve nepetalactones, and a discernable difference in nepetalactone isomer stability was discovered. Identifying Nepeta chemotypes rich in dihydronepetalactone may provide more resilient botanicals as starting materials for processing.
Risk of Suicidal Ideation and Behavior Following Early‐Onset Idiopathic Restless Legs Syndrome Treatment
Authors: Costales Brianna , Vouri Scott M. , Brown Joshua D. , Setlow Barry , Goodin Amie J.
Published: August 2024

Purpose

To estimate incidence rates of suicidal ideation and behavior following treatment initiation with gabapentinoids or dopamine agonists (DAs) in patients with newly diagnosed early‐onset idiopathic restless legs syndrome (RLS) and to examine suicidal behavior risk, comparing between those receiving gabapentinoids and DAs.

Methods

A new user retrospective cohort study using MarketScan claims data from 2012 to 2019 was conducted. Exposures were monotherapy gabapentinoids or DAs initiated within 60 days of new RLS diagnosis. Three varying outcome measures of suicidality were examined and incidence rates were calculated for each. A log‐binomial regression model the estimated relative risk (RR) of the outcomes with gabapentinoids. Propensity score weighting adjusted for baseline covariates, including age, substance use disorders, hyperlipidemia, antipsychotic use, hypnotic/sedative use, and mood stabilizer use, which were most imbalanced before weighting.

Results

The cohort included 6672 patients, with 4986 (74.7%) initiating a DA and 1686 (25.3%) initiating a gabapentinoid. Incidence rates for all outcome measures were higher in the gabapentinoid group (suicidality: 21.6 vs. 10.7 per 1000 person‐years; suicidality with self‐harm: 23.0 vs. 11.1 per 1000 person‐years; overdose‐ and suicide‐related events: 30.0 vs. 15.5 person‐years). Associated risk of suicidality (adjusted RR, 1.27 [95% CI, 0.86–1.88]); suicidality with self‐harm (adjusted RR, 1.30 [95% CI, 0.89–1.90]); or overdose‐ and suicide‐related events (adjusted RR, 1.30 [95% CI, 0.93–1.80]) was not significant with gabapentinoids.

Conclusions

Incidence rates for suicidal ideation and behavior were higher among the gabapentinoid group, although increased risk was not detected after adjustment. A possible signal cannot be ruled out given limitations of the data and rarity of the outcome.
Synthesis and characterization of additively manufactured microcapsule‐reinforced polylactic acid composites for autonomous self‐healing
Authors: Mudakavi Deepak , G Karunya , Varsha Patel , M Adinarayanappa Somashekara
Published: August 2024

Material extrusion‐based additive manufacturing (AM) process builds the objects/structures through a precise feedstock deposition in a layer‐by‐layer manner. Polylactic acid (PLA) is a popular biodegradable feedstock in AM, while octyl methoxycinnamate (OMC) is known for its eco‐friendliness and ultraviolet (UV) protection properties. The present study focuses on the novel infusion methodology of OMC‐based microcapsules into PLA to develop self‐healing composite filaments. Post‐composition iterations, the optimum compositions for the filler and plasticizer were determined, and the filaments were extruded. Microcapsule‐infused PLA and the neat PLA samples were printed as per the American Society for Testing and Materials (ASTM) standard. The uniaxial tensile test results showed that the failure strain endured by the microcapsule‐infused samples was about 10 times more than the neat PLA counterparts. It is attributed to the effective load distribution and the complex polymerization reaction (due to the interaction of OMC with the matrix). Fracture surface morphology of the samples via optical microscopy (OM) and field emission scanning electron microscope (FESEM) affirmed the strong PLA‐OMC interface. A depreciation in the Brinell Hardness for the microcapsule‐based samples was due to the localized indenter force, causing greater damage in a narrow area than microcapsule ruptures' healing ability.

Highlights

The optimized composition of PLA: plasticizer:microcapsule is 1:0.04:0.05.

Microcapsule‐infused PLA has improved Young's modulus and failure strain.

Interaction with microcapsules improves elastic behavior and self‐healing.

FESEM reveals close bonding of microcapsule with the PLA matrix.
Effect of antibacterial masterbatches selection on the crystal structure and properties of nanosilver composite materials
Authors: Tian Chengcheng , Li Yang , Liu Li‐Zhi , Wang Yuanxia , Shi Ying
Published: August 2024

The distribution of nanosilver in composite materials with two different matrices is related to the selection of antibacterial masterbatches, which has a profound impact on the antibacterial effectiveness of the composite materials. This study utilized ethylene‐vinyl acetate (EVA) and polypropylene (PP) as base materials to fabricate two types of nanosilver composite materials (C1‐EVA/PP and C2‐EVA/PPP) employing varying methods of antimicrobial masterbatches incorporation. Additionally, EVA‐Ag and PP‐Ag nanosilver composite materials were fabricated via melt blending, along with corresponding neat materials and blends (EVA, PP, and C0‐EVA/PP) for comparison. The study results indicate that the addition of nanosilver did not affect the functional groups of either the neat materials and the EVA/PP blends. SEM analysis revealed that nanosilver was dispersed unevenly in the C1‐EVA/PP substrate, while it was more uniformly distributed in the C2‐EVA/PP substrate. In the antibacterial test, the antibacterial rate of C2‐EVA/PP was higher than that of C1‐EVA/PP (56.0% vs. 40.0%). However, all silver‐containing composite materials did not exhibit antibacterial properties in the agar diffusion test. Additionally, nanosilver exhibited an induced crystallization effect on the PP phase of the C2‐EVA/PP composite material, increasing its Tc2 by 0.8°C. Compared with pure PP, the long period of PP‐Ag increased by 0.7 nm, and its impact resistance improved by 13.8%. By comparison, the long period of EVA‐Ag composite materials increased by only 0.2 nm compared to pure EVA. Both C1‐EVA/PP and C2‐EVA/PP composite materials showed 0.3 nm increase in long period compared to C0‐EVA/PP, with their impact resistance improving by 3.1% and 10.3%, respectively, compared to C0‐EVA/PP. The introduction of nanosilver increased the storage modulus, loss modulus, and apparent viscosity of EVA/PP blends. Optical performance analysis shows that nanosilver increases the internal haze of C1‐EVA/PPP by 60% while reducing the transmittance by 0.3%. The effect of nanosilver on the optical properties of C2‐EVA/PPP composites is relatively small. Therefore, this study provides theoretical guidance for the selection of processing methods for dual‐phase antibacterial materials.

Highlights

Different antibacterial masterbatch impacts silver distribution in composites.

The addition of nanosilver can improve the impact performance of materials.

Two process methods were used to prepare low‐silver content composite materials.

The antibacterial rate of C2‐EVA/PP is higher than C1‐EVA/PP (56% vs. 40%).

This study guides the processing methods for dual‐phase antibacterial materials.
Comparison of different attract‐and‐kill device densities to control the adult population of Popillia japonica (Coleoptera: Scarabaeidae)
Authors: Paoli Francesco , Barbieri Francesco , Iovinella Immacolata , Sciandra Chiara , Barzanti Gian Paolo , Torrini Giulia , Sabbatini Peverieri Giuseppino , Mazza Giuseppe , Benvenuti Claudia , Sacco Davide , Martinetti Davide , Roversi Pio Federico , Marianelli Leonardo
Published: August 2024

BACKGROUND

Popillia japonica Newman is a scarab beetle native to Japan that is considered a serious pest outside its native range. It can feed on more than 400 host plants and spread about 10 km per year in invaded territories, therefore it is considered the second most important quarantine pest in Europe. Both chemical and biological insecticides have been used for control, with variable results. Despite ongoing efforts, P. japonica remains a threat in invaded countries, and it is necessary to test more effective and sustainable solutions in the context of integrated pest management. Here we present a study on long‐lasting insecticide‐treated nets (LLINs) assembled in semiochemical‐baited attract‐and‐kill devices (A&Ks) as a means to control adults of P. japonica with low environmental impact. This study complements previous ones in which we first evaluated the effectiveness of the LLINs in the laboratory and then tested both effectiveness and duration in field‐exposed A&Ks against P. japonica. In the present work we compared the effectiveness of three different densities of A&Ks per hectare in areas where the population of P. japonica was numerically homogeneous.

RESULTS

The different densities of A&K (1, 2, 4 A&Ks per ha) resulted in an overall reduction of the population of P. japonica by about two thirds in comparison to the control area.

CONCLUSIONS

This study suggests that the use of one A&K per hectare, requiring minimal management effort, is an effective ratio for reducing local populations of P. japonica. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Universal Quantum Fisher Information and Simultaneous Occurrence of Landau‐Class and Topological‐Class Transitions in Non‐Hermitian Jaynes‐Cummings Models
Authors: Ying Zu‐Jian
Published: August 2024

Light‐matter interactions provide an ideal testground for interplay of critical phenomena, topological transitions, quantum metrology, and non‐Hermitian physics with high controllability and tunability. The present work considers two fundamental non‐Hermitian Jaynes‐Cummings models in light‐matter interactions that possess real energy spectra in parity‐time (PT) symmetry and anti‐PT symmetry. The quantum Fisher information is shown to be critical around the transitions at the exceptional points and exhibit a super universality, with respect to different parameters, all energy levels, both models, symmetric phases, and symmetry‐broken phases, which guarantees a universally high measurement precision in quantum metrology. In particular, the transitions are found to be both symmetry‐breaking Landau‐class transitions (LCTs) and symmetry‐protected topological‐class transitions (TCTs), thus realizing a simultaneous occurrence of critical LCTs and TCTs that are conventionally incompatible due to contrary symmetry requirements. Besides establishing a paradigmatic case to break the incompatibility of the LCTs and the TCTs in non‐Hermitian systems, the both availabilities of the sensitive critical feature and the robust topological feature can also provide more potential for designing quantum devices or sensors.
Dynamic event‐triggered leader‐following bipartite consensus of second‐order multi‐agent systems under DoS attacks
Authors: Wang Xiao , Liu Jian , Wu Yongbao , Sun Changyin
Published: August 2024

This article investigates the bipartite secure consensus of the second‐order leader‐follower multi‐agent systems (MASs) against aperiodic denial of service (DoS) attacks. First, a new dynamic event‐triggered strategy is proposed for the consensus control. Compared with the static event‐triggered strategy, the dynamic event‐triggered protocol can reduce the trigger times and save resources by introducing an internal dynamic variable. Different from the secure consensus results which only discussed the cooperative links, based on the theory of the structurally balanced graph, this article considers cooperative and antagonistic interactions among agents simultaneously for complex behaviors of them. Besides, the characteristics of the DoS attacks are analyzed in detail and the secure consensus is achieved by utilizing the Lyapunov theory and inductive methods. Finally, the Zeno behavior is excluded and the availability of the designed algorithms is demonstrated by numerical simulations.
Grain Manipulation by Annealing Treatment Realizes High‐Performance N‐Type Bi2Te2.4Se0.6 Thermoelectric Material and Device
Authors: Chen Lidong , Guo Zhe , Wu Gang , Tan Xiaojian , Sun Peng , Wu Jiehua , Liu Guo‐Qiang , Jiang Jun
Published: August 2024

Bi2Te3‐based materials play a crucial role in solid cooling and power generation, but the rapidly deteriorated ZT with rising temperatures above 450 K severely limits further applications. Here, this paper reports a novel preparation method of annealing treatment for molten ingot, which can enhance the thermoelectric performance of n‐type Bi2Te2.4Se0.6 in a wide temperature range. Instead of conventional halides, copper is adopted to regulate the carrier concentration and grain size to optimal levels. During the process of annealing at 573 K for 4 h, the number of twins significantly increases and the grains of Cu‐doped samples become larger and more oriented. These optimizations lead to higher carrier mobility with similar carrier concentration compared with the sample without heat treatment. The synergistic effects of Cu doping and annealing treatment realize a high average ZT of 0.89 within 300–600 K in n‐type Cu0.02Bi2Te2.4Se0.6. Combined with p‐type (Bi,Sb)2Te3, the fabricated thermoelectric device exhibits a high conversion efficiency of 6.9% at a temperature difference of 300 K. This study suggests that annealing treatment is a simple and effective scheme to promote the applications of n‐type Bi2(Te,Se)3 in a wide temperature range.
Mycobacterium genavense detection in a blood smear from a domestic ferret
Authors: Fonseca Joana , Silveira João , Duarte Vanessa , Canejo‐Teixeira Rute , Patrício Rui , Belas Adriana
Published: August 2024

The domestic ferret is sensitive to mycobacterial infections, which are likely underdiagnosed. There are limited reports of therapy for mycobacteriosis in ferrets and most have failed. A ferret in poor body condition revealed marked organomegaly on diagnostic imaging. The complete blood count revealed a mild pseudoeosinophilia, which might be attributed to negatively stained bacilli phagocytised by monocytes observed in the blood smear. Ziehl–Neelsen stain was performed and showed acid‐fast bacilli within monocytes. Fine‐needle aspirates of the spleen and liver revealed the same finding. Mycobacterium genavense was identified by PCR and DNA sequencing from peripheral blood. Treatment with rifampicin, clarithromycin and enrofloxacin was initiated. The disseminated mycobacteriosis was suspected from the observation of bacilli on the blood smear. After 16 months, the ferret is still undergoing treatment. To prevent recurrence, continued monitoring of drug toxicity and effective therapy will be maintained even after the resolution of clinical signs (mostly organomegaly).
Analysis of Multiaxial Tensile Stresses in Cold Forging Tools
Authors: Killmann Martin , Merklein Marion
Published: August 2024

Tools have a key role in cold forging as they directly influence part quality and process economics. High loads from the contact pressure exhibited by the workpiece are a major challenge regarding tool life. In complex geometries, tensile die stresses are concentrated in local areas and oriented both in axial and tangential directions. This superposition of loads leads to fatigue failure at the stress peaks. Since the interactions of multidirectional tensile stresses in cold forging tools have not been investigated in previous investigations, this paper aims to better understand the formation of local stress concentrations in axial and tensile directions as well as the possibilities to influence them. As tool loads in critical areas are difficult to measure during the process, simulation plays an important role in the evaluation of die stresses. Therefore, a model process with multiaxial tool stresses is simulated and the simulation results are compared to experimental values in order to validate the model. The simulation is then used to analyse the die load depending on the prestressing system.
Sensitivity Analysis and Formulation of the Inverse Problem in the Stochastic Approach to Modelling of Phase Transformations in Steels
Authors: Szeliga Danuta , Jażdżewska Natalia , Foryś Jakub , Kusiak Jan , Nadolski Rafał , Oprocha Piotr , Pietrzyk Maciej , Potorski Paweł , Przybyłowicz Paweł
Published: August 2024

The need for a reliable prediction of the distribution of microstructural parameters in metallic materials after processing was the motivation for this work. The model describing phase transformations, which considers the stochastic character of the nucleation of the new phase, was formulated. Numerical tests of the model, including sensitivity analysis, were performed and the optimal parameters such as time step, kind of the random numbers generator (RNG) and the number of the Monte Carlo points were determined. The validation of the model requires an application of proper coefficients corresponding to the considered materials. These coefficients have to be identified through the inverse analysis, which, on the other hand, uses optimization methods and requires the formulation of the appropriate objective function. Since the model involves stochastic parameters, it is a crucial task. Therefore, in the second part of the paper, a specific form of the objective function for the inverse analysis was developed. In the first approach, an objective function based on measurements of the average parameters was used and primary optimization was performed. Various optimization methods were tested. In the second approach, the hybrid objective function, which combined measured average transformation temperatures with a measure based on histograms, was used. Since, at this stage, we do not have measurements of the distribution of microstructural features, the basic histograms were generated by the model with the coefficients obtained in the first step of the optimization. The capability of finding the optimal solution for different starting points was evaluated and various approaches were compared. The elaborated original stochastic approach to modelling the phase transformations occurring during cooling after hot forming was validated on selected carbon steel.
Cold Forging of Hollow Shafts with Variable Wall Thickness by Means of an Adjustable Forming Zone
Authors: Weiß Alexander , Liewald Mathias
Published: August 2024

Hollow shafts are widely used due to their high weight saving potential and only slight reduction of their bending and torsional stiffness compared to solid shafts. Additional weight savings can be achieved by a specific material allocation within the hollow shaft, which can be achieved by varying their wall thickness. The production of such hollow shafts by conventional forming processes and multiple forming stages appears quite costly today. Alternatively, incremental forming processes could be used, but those are very time-consuming. In order to overcome these disadvantages, this paper proposes a special cold forging process characterized by a locally adjustable forming zone, which allows the production of hollow shafts with variable wall thickness within one single press stroke. In previous numerical investigations, the potential of this cold forging process for the production of customized hollow shafts with predefined wall thickness locations or internal splines has already been demonstrated. However, experimental validation has not yet been carried out. In this paper, the first experimental results on hollow shafts produced with wall thickness changes along their longitudinal direction are presented. The experimental setup and the results of the tests carried out so far are described. Furthermore, the experimental results are compared with the numerical calculations of this new forming process.
Numerical and Experimental Analysis of the Influence of Manufacturing Parameters in Additive Manufacturing SLM-PBF on Residual Stress and Thermal Distortion in Parts of Titanium Alloy Ti6Al4V
Authors: Santos M. O. , Maiolini A. S. F. R. , Miranda F. , Farias A. , Seriacopi V. , Bordinassi E. C. , Batalha G. F.
Published: August 2024

Additive manufacturing (AM) has become popular in recent years due to its integration with Industry 4.0 and for enabling the production of complex and optimized geometries. However, the process leads to disadvantages, such as thermal distortions and the generation of residual stresses due to thermal gradients during the parts production. Based on these undesirable characteristics, this work aims to model AM numerically through the Finite Element Method (FEM), besides obtaining experimental results that relate the impact of different process parameters, such as laser power, speed, and hatch distance on the residual stress and distortions distribution, to parts generated by Selective Laser Melting (SLM)—Powder Bed Fusion (PBF)—of titanium alloy Ti6Al4V. The experimental tests, as well as the numerical analyses, followed a factorial design. The results for thermal distortions are excellent with differences below 4.5% between the manufactured and simulated parts. As for the results of residual stresses measured at a single point on the lateral face, for most of the results, the difference was less than 4%; however, there was a large dispersion of results. When the values of average residual stresses were considered in the simulation, the results had statistical relevance and showed greater robustness. It was found that the average diameter of Ti6Al4V titanium parts was greatly influenced by the laser power followed by the hatch distance. The increase in power increased the average diameter of the samples, while the increase in speed and hatch decreased their diameter. In turn, increasing laser power decreased residual stress, while increasing speed and hatch tended to increase the mean residual stress.
Reduced Three-Dimensional Model for Cold Rolling Simulation of Aluminium Alloys
Authors: Pachnek Florian , Simon Peter , Zeman Klaus
Published: August 2024

Mathematical modelling and computational analyses allow to deepen the understanding of manufacturing processes, to ensure high product quality and to reduce experimental efforts for the optimization of product properties and production processes. In order to predict the evolution of flat rolled aluminium product properties and their interdependence with process parameters, virtual representations of the entire process chain including process models of hot rolling, coiling, and cold rolling operations are highly beneficial. Starting from the solid foundation of a comprehensively validated 3D model of the hot rolling process of various aluminium alloys, the present work presents a 3D thermo-mechanical cold rolling simulation model using the commercial finite element code LS-DYNA. The material behaviour is considered by means of a user defined material model according to a modified dislocation density based flow model. The calculated microstructural and deformation history of the hot rolled strip is considered as input for the developed cold rolling model allowing for seamless prediction of product properties. For numerical studies, a modular modelling approach is pursued, comprising tailor-made simplifications depending on actual applications and research problems. For time efficient multi-pass simulations in an industrial environment, a reduced model with plane strain conditions is derived that extends the predictability of product properties and process parameters from hot rolling over coiling to cold rolling. Simulation results and computational costs are compared with detailed 3D models. Strip tensions can be adjusted showing the expected effects on roll separating forces and minimum rolled thickness. To ensure the desired strip tensions in the numerical model, a sensor-based control of strip tensions is implemented. For validation purposes, measured rolling forces from industrial pass schedules for 6xxx series alloys are compared against simulation results.
Effect of Welding Processes on Microstructure and Mechanical Properties of Laser-Welded Al-Si-Coated 22MnB5 Steel
Authors: He Qi , Hou Zeran , Kong Jie , Deng Lulu , Ma Xiaolong , Min Junying
Published: August 2024

Tailor welded blank (TWB) has been developed in the automotive industry to improve structural safety and material efficiency. Al-Si-coated 22MnB5 steel is the main material for laser tailor welding due to its resistance to oxidation and decarburization during hot stamping, which can otherwise deteriorate the performance of welded joints. This study investigates the use of partial ablation welding (PAW) and filler wire welding (FWW) as compared to traditional self-fusion welded (SFW) to enhance the mechanical performances of Al-Si-coated 22MnB5 steel welded joints. The effects of welding processes on the microstructure of welded joints as well as the mechanism of performance enhancement were investigated. Tensile testing results showed that PAW and FWW joints consistently fractured at the base material, whereas the SFW joints fractured at the weld seam. The maximum tensile loads of PAW and FWW joints were, respectively, 12.75 and 12.93% higher than that of SFW joints. Additionally, the microhardness distribution of PAW and FWW joints is uniform with no softening zone. Finally, the study discusses the improved mechanical properties of PAW and FWW joints in terms of microstructural evolution and diffusion of Al elements.
Integration of Material Simulation to Extend the Accuracy of FEM Results for Metallic Forming Processes
Authors: Helas Kristin , Biba Nikolay
Published: August 2024

Nowadays, almost all metallic forming processes can be mapped by FEM simulation. Demands on FEM simulation are becoming increasingly higher with regard to the representation of very fine tolerances, whether in terms of temperature or dimensional accuracy. The combination of a FEM software suitable for the forming process and a connected materials database is a great potential to enlarge these precision figures. In the article, real simulation examples with QForm UK are used to show how this combination positively affects the accuracy of simulation results. For this purpose, several material data—such as flow curves, temperature-dependent properties, or CCT diagrams—and material models—such as the recrystallization or phase transformation model—from the materials database MatILDa® are applied. Hereby, the possibilities of material simulation are demonstrated and practical methods to improve individual simulation projects are given.
Productivity Growth
Authors: Prados de la Escosura Leandro
Published: August 2024

This chapter assesses long-term productivity growth and its immediate determinants in Spain. Over the last 170 years, output per hour worked dominated GDP growth, while hours worked per person shrank by one-quarter and population trebled. Half of labour productivity growth resulted from capital deepening and one-third from efficiency gains (total factor productivity). Labour productivity proceeded steadily, accelerating during the 1920s and from the mid-1950s to the late 1980s, but decelerated thereafter as capital deepening slowed down and TFP stagnated due to the fact that expanding sectors attracted less investment-specific technological progress, largely a result of institutional constraints.
B meson mixing at NNLO: technical aspects
Authors: Reeck Pascal , Shtabovenko Vladyslav , Steinhauser Matthias
Published: August 2024

Abstract

We provide details to several technical aspects which are important for the calculation of next-to-next-to-leading order corrections to the mixing of neutral B mesons. This includes the computation of the master integrals for finite charm and bottom quark masses, projectors for products of up to 22 γ matrices and tensor integrals with up to rank 11.
Prostatakarzinom-Screening? Nur evidenzbasiert, risikoadaptiert und organisiert!
Authors: Albers Peter , Becker Nikolaus
Published: August 2024

Aufgrund einer Kommissionsempfehlung der Europäischen Union aus dem Jahr 2022, neue Screeningstrategien für das Bronchialkarzinom, das Magenkarzinom und das Prostatakarzinom zu entwickeln, ist auch Deutschland dazu aufgerufen, sein Prostatakarzinom-Früherkennungsprogramm zu überarbeiten. In diesem Diskussionsartikel wird eine Übersicht über neue Ergebnisse zur Prostatakrebsfrüherkennung gegeben, die auf die Empfehlung eines organisierten, risikoangepassten Prostatakrebsscreenings hinauslaufen. Basierend auf den ersten Resultaten der aktuellen deutschen Prostatascreening-Studie PROBASE und neuer internationaler Literatur sollten Modellprojekte begonnen werden, die die spezifischen Bedingungen für ein organisiertes risikoadaptiertes Prostatakarzinom-Screeningprogramm erkunden.
Experimental investigations on the behaviour of structural-sized wood-CFRP composite beams in local fire
Authors: Kawecki Bartosz , Pieńko Michał , Lipecki Tomasz , Stachowicz Andrzej
Published: August 2024

The study involved combustion of 24 structural-sized beams under three-point bending subjected to substantial loading prior to ignition, reaching 90% of characteristic load-carrying capacity. A localised fire exposure zone was established proximal to the region experiencing the highest bending moment. The specimens were categorised into two groups: the first consisted of tituted by glued-laminated timber (B), and the second comprised wood-CFRP (carbon fibre reinforced polymer) composite (BW). Initial measurements encompassed pre-ignition static deflection and load. Subsequently, the specimens underwent controlled combustion, during which parameters including burning duration and deflection up to failure, were documented. Following cooling with sand, two cross-sectional slices were extracted from each fractured beam, enabling to find vector-based contours of the remaining cross-section. The charring rate and the approximate heat flux density for each test were determined, enabling a direct comparison of the results. A statistically significant number of specimens was examined, facilitating a comparative analysis between reinforced and unreinforced beams concerning failure time and form. Incorporating CFRP tapes among wooden constituents was found to increase the fire resistance of the structure, however, the thickness of the wooden material enveloping the CFRP composite emerges as a pivotal determinant. This issue needs thorough testing under standard fire in the future. Nevertheless, the fact is that adding CFRP tapes engenders a distinct form of beam collapse, transitioning from instantaneous cracking in B-beams to ductile failure in BW-beams.
A review of inverse problems for generalized elastic media: formulations, experiments, synthesis
Authors: Fedele Roberto , Placidi Luca , Fabbrocino Francesco
Published: August 2024

Starting from the seminal works of Toupin, Mindlin and Germain, a wide class of generalized elastic models have been proposed via the principle of virtual work, by postulating expressions of the elastic energy enriched by additional kinematic descriptors or by higher gradients of the placement. More recently, such models have been adopted to describe phenomena which are not consistent with the Cauchy-Born continuum, namely the size dependence of apparent elastic moduli observed for micro and nano-objects, wave dispersion, optical modes and band gaps in the dynamics of heterogeneous media. For those structures the mechanical response is affected by surface effects which are predominant with respect to the bulk, and the scale of the external actions interferes with the characteristic size of the heterogeneities. Generalized continua are very often referred to as media with microstructure although a rigorous deduction is lacking between the specific microstructural features and the constitutive equations. While in the forward modelling predictions of the observations are provided, the actual observations at multiple scales can be used inversely to integrate some lack of information about the model. In this review paper, generalized continua are investigated from the standpoint of inverse problems, focusing onto three topics, tightly connected and located at the border between multiscale modelling and the experimental assessment, namely: (i) parameter identification of generalized elastic models, including asymptotic methods and homogenization strategies; (ii) design of non-conventional tests, possibly integrated with full field measurements and advanced modelling; (iii) the synthesis of meta-materials, namely the identification of the microstructures which fit a target behaviour at the macroscale. The scientific literature on generalized elastic media, with the focus on the higher gradient models, is fathomed in search of questions and methods which are typical of inverse problems theory and issues related to parameter estimation, providing hints and perspectives for future research.
Contractile effects of stimulation of D1-dopamine receptors in the isolated human atrium
Authors: Gergs U. , Pham T. H. , Rayo Abella L. M. , Hesse C. , Grundig P. , Dhein S. , Hofmann B. , Neumann J.
Published: August 2024

Dopamine receptors have been claimed not to directly increase contractility in the human heart. Therefore, we performed contraction experiments in isolated electrically driven human atrial preparations (HAP). For comparison, we performed contraction experiments with left atrial preparations of transgenic mice which harbor a cardiac overexpression of human D1-dopamine receptors (D1-TG). In D1-TG, first we noted that dopamine (10 nM–10 µM cumulatively applied) in the presence of propranolol exerted a concentration- and time-dependent positive inotropic effect in D1-TG. In a similar fashion, dopamine increased force of contraction in the presence of 0.4 µM propranolol in HAP and these effects were amplified by pre-treatment with inhibitor of phosphodiesterase III (1 µM) cilostamide. Moreover, contractile effects of dopamine in the presence of propranolol 0.4 µM in HAP were antagonized by odapipam, haloperidol, or raclopride. Ten micromolars of fenoldopam in the presence of cilostamide increased force of contraction in HAP and this effect was antagonized by SCH 23390. We conclude that stimulation of human D1-dopamine receptors can increase force of contraction in the HAP.
The effects of N-acetyl cysteine on intrinsic functional connectivity and neural alcohol cue reactivity in treatment-seeking individuals with alcohol use disorder: a preliminary study
Authors: Logge Warren B , Haber Paul S , Hurzeler Tristan P , Towers Ellen E , Morley Kirsten C
Published: August 2024

N-acetyl cysteine (NAC) is a potential pharmacotherapy for alcohol use disorder (AUD), but it is not known whether it modulates neural activation to alcohol cues or intrinsic functional connectivity. We investigated whether NAC attenuates (i) alcohol cue-elicited activation, and (ii) intrinsic functional connectivity compared to placebo in patients with AUD. In this preliminary study, twenty-three individuals (7 females) with moderate-severe AUD received daily NAC (2400 mg/day, n = 9), or a placebo (n = 14) for at least 2 weeks. Participants completed a pre-treatment functional magnetic resonance imaging session (T0) and a post-treatment session (T1) comprising resting-state and visual alcohol cue reactivity task acquisitions. Activation differences between sessions, treatment, and session-by-treatment interaction were assessed. Resting-state functional connectivity examined using 377 node ROI-to-ROIs evaluated whether NAC reduced intrinsic functional connectivity after treatment. There were no differences in alcohol cue reactivity for brain activation or subjective craving between NAC and placebo during treatment or across sessions, or significant interaction. A significant treatment-by-time interaction, with reduced intrinsic connectivity was observed after treatment (T1) for NAC-treated compared to placebo-treated patients in the posterior cingulate node (9, left hemisphere) of the dorsal attentional network and connections to salience, ventral-attentional, somatosensory, and visual-peripheral networks implicated in AUD. NAC reduced intrinsic functional connectivity in patients with moderate-severe AUD after treatment compared to placebo, but did not attenuate alcohol cue-elicited activation. However, the absence of cue reactivity findings may result from low power, rather than the absence of cue reactivity findings associated with NAC. These results provide preliminary evidence that NAC treatment may modulate intrinsic functional connectivity brain activation in patients with alcohol use disorder, but replication in larger studies are required to determine the strength of this effect and any associations with clinical outcomes.

Clinical Trials Registration: ClinicalTrials.gov Identifier: NCT03879759.
Snail shell shape, force of attachment, and metabolic rate together cope with the intertidal challenge
Authors: Alcaraz Guillermina , Alvarez-Galicia Aldair , Ramírez-Sánchez Marcia M. , Burciaga Luis M.
Published: August 2024

Inhabitants of rocky intertidal shores, including gastropods, require specific adaptations to cope with numerous challenges that vary across the intertidal levels. We collected Stramonita biserialis snails from upper (wave-protected and intense predation) and lower (wave-exposed and low predation) intertidal sites to compare the following traits: shell skeleton (ventral and abaxial lateral views of shell shape, thickness, and mass), foot size, energy metabolism, and attachment strength to determine whether the trait values of snails from each zone fit the environmental challenges they face. We used a Principal Component Analysis to reduce the dimensionality of the data. Multivariate Analysis of Covariance (MANCOVA) for comparing characteristics between the two intertidal zones, and Partial Least Squares (PLS) analyses for testing the integration of overall snail characteristics. The traits of the snails of the two intertidal sites matched with the adaptations expected to allow them to cope with their contrasting challenges. The snails from the lower intertidal had more streamlined shells (which reduces drag forces) and a larger aperture and foot extension (which increase the strength of their attachment to the substrate) compared to snails from the upper sites. Snails from the lower intertidal also had a high mass-specific metabolism and soft body proportion, indicating that these snails from the wave-exposed sites have an energetically active musculature that matches their strong substrate attachment. The thin shell walls of the snails of the lower intertidal match the relatively low predatory pressure there.
Decentralized pure exchange processes on networks
Authors: Cassese Daniele , Pin Paolo
Published: August 2024

We define a class of pure exchange Edgeworth trading processes that under minimal assumptions converge to a stable set in the space of allocations, and characterise the Pareto set of these processes. Choosing a specific process belonging to this class, that we define fair trading, we analyse the trade dynamics between agents located on a weighted network. We determine the conditions under which there always exists a one-to-one map between the set of networks and the set of limit points of the dynamics, and derive an analog of the Second Welfare Theorem for networks. This result is used to explore what is the effect of the network topology on the trade dynamics and on the final allocation.
Animal and organoid models to elucidate the anti-fibrotic effect of steroid on biliary atresia
Authors: Liu Fangran , Lui Vincent Chi Hang , Wu Zhongluan , Blakeley Paul David , Tang Clara Sze Man , Tam Paul Kwong Hang , Wong Kenneth Kak Yuen , Chung Patrick Ho Yu
Published: August 2024

Purpose

We performed animal and organoid study to evaluate the anti-fibrotic effect of steroid on biliary atresia (BA) and the underlying patho-mechanism.

Methods

BA animal models were created by inoculation of mice on post-natal day 1 with rhesus rotavirus (RRV). They received either 20 µl phosphate-buffered saline (PBS) or steroid from day 21 to day 34. On day 34, their serum samples were collected for hormonal markers. Necrosis, fibrosis and CK 19 expression in the liver were evaluated. Liver organoids were developed and their morphology as well as bulk RNA sequencing data were analyzed.

Results

Twenty-four mice developed BA features after RRV injection and were equally divided into steroid and PBS groups. On day 34, the weight gain of steroid group increased significantly than PBS group (p < 0.0001). All mice in the PBS group developed liver fibrosis but only one mouse in the steroid group did. Serum bilirubin and liver parenchymal enzymes were significantly lower in steroid group. The morphology of liver organoids were different between the two groups. A total of 6359 differentially expressed genes were found between steroid group and PBS group.

Conclusion

Based on our findings obtained from RRV-induced BA animal and organoid models, steroid has the potential to mitigate liver fibrosis in BA.
Angiography-derived physiological patterns of coronary artery disease: implications with post-stenting physiology and long-term clinical outcomes
Authors: Fezzi Simone , Del Sole Paolo Alberto , Burzotta Francesco , Leone Antonio Maria , Ding Daixin , Terentes-Printzios Dimitrios , Trani Carlo , Bonizzi Luca , Sgreva Sara , Andreaggi Stefano , Huang Jiayue , Pesarini Gabriele , Tavella Domenico , Prado Guy , Vicerè Andrea , Oikonomou Dimitrios , Gkini Konstantia Paraskevi , Galante Domenico , Tsioufis Konstantinos , Vlachopoulos Charalambos , Wijns William , Ribichini Flavio , Tu Shengxian , Scarsini Roberto
Published: August 2024

Background

Physiological patterns of coronary artery disease (CAD) have emerged as potential determinants of functional results of percutaneous coronary interventions (PCI) and of vessel-oriented clinical outcomes (VOCE).

Objectives

In this study, we evaluated the impact of angiography-derived physiological patterns of CAD on post-PCI functional results and long-term clinical outcomes.

Methods

Pre-PCI angiography-derived fractional flow reserve (FFR) virtual pullbacks were quantitatively interpreted and used to determine the physiological patterns of CAD. Suboptimal post-PCI physiology was defined as an angiography-derived FFR value ≤ 0.91. The primary endpoint was the occurrence of VOCE at the longest available follow-up.

Results

Six hundred fifteen lesions from 516 patients were stratified into predominantly focal (n = 322, 52.3%) and predominantly diffuse (n = 293, 47.7%). Diffuse pattern of CAD was associated with lower post-PCI angiography-derived FFR values (0.91 ± 0.05 vs. 0.94 ± 0.05; p = 0.001) and larger rate of suboptimal post-PCI physiology (43.0 vs. 22.7%; p = 0.001), as compared to focal CAD. At the median follow-up time of 37 months (33–58), post-PCI suboptimal physiology was related to a higher risk of VOCE (16.2% vs. 7.6%; HR: 2.311; 95% CI 1.410–3.794; p = 0.0009), while no significant difference was noted according to baseline physiological pattern. In diffuse disease, the use of intracoronary imaging was associated with a lower incidence of long-term VOCE (5.1% vs 14.8%; HR: 0.313, 95% CI 0.167–0.614, p = 0.030).

Conclusions

Suboptimal post-PCI physiology is observed more often in diffusely diseased arteries and it is associated with higher risk of VOCE at follow-up. The use of intravascular imaging might improve clinical outcomes in the setting of diffuse CAD.