Strain Demands Research Articles

The association between leisure-time physical activity and cardiorespiratory and muscular fitness and job strain-Study with a Northern Finland birth cohort of 1966.

Job strain is a major concern in the workplace. Work-related stress is an increasing challenge worldwide as it is the leading cause of long-term sickness absences, disability pensions and lower productivity. Rarely studied simultaneously, both leisure-time physical activity (LTPA) and physical fitness (PF), which comprises cardiorespiratory fitness (CRF) and muscular fitness (MF), may have potential in preventing and managing job strain. The current study aimed to investigate whether LTPA, CRF and MF predict perceived job strain. In addition, the study examines reverse associations, that is, whether job strain predicts LTPA, CRF and MF. We used longitudinal population-based data from a Northern Finland birth cohort of 1966 (n=5363) to analyse LTPA, CRF and MF as well as job strain and its components, job demands and job control, at age 31years (1997) and 46years (2012). Leisure-time physical activity was measured with a self-reported questionnaire whereas CRF and MF were measured as part of clinical examination. Linear regression analyses were used to analyse the data. In both men (n=2548) and women (n=2815), higher baseline MF predicted lower job strain and job demands 15years later. In women, higher baseline total LTPA predicted higher job demands, whereas in men, higher CRF predicted lower job strain and higher job control. These associations remained significant, also when adjusted for education and occupational status. In the analyses on reverse associations, higher job control and higher job demands were linked to higher leisure-time moderate-to-vigorous physical activity (MVPA) and total LTPA 15years later among both men and women, except for the association between job demands and total LTPA among women. These associations remained significant after adjustment for education and occupational status, except for the association of job control with MVPA and total LTPA among men. The association of higher job demands and total LTPA became significant in women. We conclude that LTPA and PF seem beneficial in preventing and managing job strain.

Insights into the Preparation of and Evaluation of the Bactericidal Effects of Phage-Based Hydrogels.

The rise of antibiotic-resistant strains demands new alternatives in antibacterial treatment. Bacteriophages, with their precise host specificity and ability to target and eliminate bacteria safely, present a valuable option. Meanwhile, hydrogels, known for their excellent biodegradability and biocompatibility, serve as ideal carriers for bacteriophages. The combination of bacteriophages and hydrogels ensures heightened phage activity, concentration, controlled release, and strong antibacterial properties, making it a promising avenue for antibacterial treatment. This article provides a comprehensive review of different crosslinking methods for phage hydrogels, focusing on their application in treating infections caused by various drug-resistant bacteria and highlighting their effective antibacterial properties and controlled release capabilities.

CRISPR/Cas9 mediated targeted knock-in of eglA gene to improve endoglucanase activity of Aspergillus fumigatus LMB-35Aa

Bioeconomy goals for using biomass feedstock for biofuels and bio-based production has arisen the demand for fungal strains and enzymes for biomass processing. Despite well-known Trichoderma and Aspergillus commercial strains, continuous bioprospecting has revealed the fungal biodiversity potential for production of biomass degrading enzymes. The strain Aspergillus fumigatus LMB-35Aa has revealed a great potential as source of lignocellulose-degrading enzymes. Nevertheless, genetic improvement should be considered to increase its biotechnological potential. Molecular manipulation based on homologous direct recombination (HDR) in filamentous fungi poses a challenge since its low recombination rate. Currently, CRISPR/Cas9-mediated mutagenesis can enable precise and efficient editing of filamentous fungi genomes. In this study, a CRISPR/Cas9-mediated gene editing strategy for improving endoglucanase activity of A. fumigatus LMB-35Aa strain was successfully used, which constitutes the first report of heterologous cellulase production in filamentous fungi using this technology. For this, eglA gene from A. niger ATCC 10,864 was integrated into conidial melanin pksP gene locus, which facilitated the selection of edited events discerned by the emergence of albino colonies. Heterologous production of the EglA enzyme in a biofilm fermentation system resulted in a 40% improvement in endoglucanase activity of the mutant strain compared to the wild type.

AutoBioTech─A Versatile Biofoundry for Automated Strain Engineering.

The inevitable transition from petrochemical production processes to renewable alternatives has sparked the emergence of biofoundries in recent years. Manual engineering of microbes will not be sufficient to meet the ever-increasing demand for novel producer strains. Here we describe the AutoBioTech platform, a fully automated laboratory system with 14 devices to perform operations for strain construction without human interaction. Using modular workflows, this platform enables automated transformations of Escherichia coli with plasmids assembled via modular cloning. A CRISPR/Cas9 toolbox compatible with existing modular cloning frameworks allows automated and flexible genome editing of E.coli. In addition, novel workflows have been established for the fully automated transformation of the Gram-positive model organism Corynebacterium glutamicum by conjugation and electroporation, with the latter proving to be the more robust technique. Overall, the AutoBioTech platform excels at versatility due to the modularity of workflows and seamless transitions between modules. This will accelerate strain engineering of Gram-negative and Gram-positive bacteria.

Real-world service costs for neovascular-AMD clinics in the United Kingdom: structured literature review and scenario analysis

Objective Current cost-effectiveness analyses (CEA) emphasize drug costs as the differentiator between NICE recommended anti-VEGF treatments but may neglect real-world non-drug costs of running nAMD services in the UK. To address this, this study identified real-world non-drug service cost items relevant to UK NHS nAMD clinics, including costs arising from operational strain (demand exceeding capacity). Methods Cost items were identified by a structured literature review of peer-reviewed and grey literature, and an expert panel of 10 UK-based ophthalmologists with relevance to real-world practice. These items underwent meta-synthesis and were then determined in a consensus exercise. Results Of 237 cost items identified, 217 (91.6%) met the consensus threshold of >0.51 and were included in the nAMD Service Non-Drug Cost Instrument (nAS). Sensitivity of cost items taken from UK Health Technology Assessment (HTA) using the nAS as the reference standard was low (HTAmin: 1.84%, 95% CI 0.50–4.65%; HTAmax: 70.51%, 95% CI 63.96–76.49%). False negative rates showed variable likelihood of misclassifying a service by cost burden depending on prevalence. Scenario analysis using cost magnitudes estimated annual per-patient clinic cost at £845 (within capacity) to £13,960 (under strain) compared to an HTAmin estimate of £210. Accounting for cost of strain under an assumed 50% increase in health resource utilization influenced cost-effectiveness in a hypothetical genericisation scenario. Conclusion Findings suggested that HTA underestimates UK NHS nAMD clinic cost burden with cost of strain contributing substantial additional unmeasured expense with impact on CEA. Given potential undertreatment due to strain, durability is suggested as one of the relevant factors in CEA of nAMD anti-VEGF treatments due to robustness under limited capacity conditions affecting UK ophthalmology services.

The strain demand of reinforced concrete bridge columns under seismic loading

The steel in reinforced concrete (RC) members that form plastic hinges must possess sufficient strain capacity to dissipate seismic deformation demands. Unfortunately, there is limited information on the seismic strain demands of bridge column plastic hinges. Instead, designers rely on a perception of cyclic strain capacity that is an approximate rule of thumb. A standard methodology needs to be established for quantifying the strain demand on these structural members as a function of the expected seismic hazard. To develop this methodology, 1944 columns were analyzed with nonlinear time-history analyses (NLTHAs) using ground motions from a range of earthquakes. This study evaluates the strain demand on RC bridge columns by defining the relationship between the strain demand and earthquake intensity. The results of the model are defined in terms of the peak tensile strain of the reinforcing bar, [Formula: see text]. The earthquake intensity with the highest correlation to the [Formula: see text] was determined to be the elastic spectral displacement at the optimal period ([Formula: see text]), which is defined as 75% of the effective period. The relationship between [Formula: see text] and [Formula: see text] can be used to predict the strain demand for an RC bridge column at a given geographic location. Results are presented as a probability density function (PDF), representing strain demand, compared to a PDF of the column capacity. The intersection of the capacity curve and demand curve represents the maximum acceptable strain given as a function of [Formula: see text]. This methodology can help understand the demand placed on a structural system given a region’s seismicity.

Determining airflow requirements in mine workings based on field measurements of actual emissions from internal combustion engine equipment

The increasing complex geological and hydrogeological conditions ore deposit mining, deeper excavation sites, and ambitious business expansion strategies, necessitate the use of high-performance, heavy-duty self-propelled machinery and winning equipment. Such activities significantly strain mine ventilation systems and demand innovative safety measures during mining.This study assesses the influence of interconnected production variables on the aerological safety of mining operations. It provides real-world data on emissions from diverse sources within mines. The analysis includes an examination of current methodologies for estimating the air volume needed to dilute exhaust gases from diesel-powered machinery. Through numerical simulation that accounts for changes over time, the study was able to predict how exhaust gas concentrations would disperse within mines. These theoretical findings were then confirmed through empirical observations made in actual mining setting The field studies conducted, alongside their thorough analysis, underscored the necessity for adopting new, more sophisticated approaches to calculate airflow requirements in mines operating ICE machinery. A particular methodology developed by the MMI of the NUST MISIS (hereinafter referred to as the Methodology) was put forward as the primary tool for this purpose. The Methodology’s precision and benefits were closely scrutinized, revealing its effectiveness in ensuring aerological safety in mines.

An Effective Control Approach of Hybrid Energy Storage System Based on FLC/Grey Wolf Optimisation

In the modern era, the integration of renewable energy sources (RES) has bolstered the autonomy of urban energy infrastructures, reducing reliance on distant sources and grids. Batteries serve as a vital bridge between power supply and fluctuating load demands within RES systems. However, the unpredictable nature of RES behavior and varying load requirements often subject batteries to repeated deep cycles and irregular charging patterns. These cycles diminish the battery’s lifespan and escalate replacement costs. This study presents an innovative control strategy for a Solar-Wind model featuring a Battery-Supercapacitor Hybrid Energy Storage System. The objective is to prolong the battery’s operational lifespan by mitigating intermittent strain and high current demands. In contrast to conventional methods, the proposed control approach incorporates a Low-Pass Filter (LPF) and a Fuzzy Logic Controller (FLC). Firstly, the LPF minimizes the oscillations in battery consumption. Simultaneously, the FLC optimizes the high current demand on the battery while vigilantly monitoring the supercapacitor’s charge levels. Moreover, Grey Wolf Optimization (GWO) is employed to fine-tune the FLC’s membership functions, ensuring optimal peak current attenuation in batteries. The effectiveness of the proposed model is benchmarked against standard control techniques, namely Rule- Based Controller and Filtration-Based Controller. Comparative analysis reveals that the proposed method substantially reduces peak current and high power requirements of the battery. Consequently, this enhances the utilization of the supercapacitor, significantly augmenting the battery’s operational life. The results demonstrate a remarkable improvement over conventional systems, emphasizing the potential of this approach in optimizing energy storage systems for sustainable, long-term performance.

Effect of fully-grouted bolts on the failure behaviors of mine pillars: Insights from block-based FDEM modeling

In this study, the Voronoi-based breakable block model (VBBM) based on the combined finite-discrete element method (FDEM) is used to investigate the failure mechanism of mine pillars and the rock-rockbolt interactions. The mechanical parameters of grout-rock and grout-bolt interfaces of a fully-grouted bolt are calibrated via numerical pull-out tests. Then, uniaxial compression tests are carried out on the reinforced pillars. The kinetic energy release rate (KERR) and crack aperture (CA) are used to evaluate the reinforcement effect. The results revealed that the VBBM can effectively characterize the damage failure mechanisms of spalling on the pillar surface and conjugate shear failure in the core zone of the pillar and reproduce the pre-peak nonlinear deformation and post-peak pseudo-ductile behaviors. The passive confining pressure generated by rockbolts is activated only when the rock mass produces sufficient deformation, and the constraints generated by different numbers of rockbolts can only affect the post-peak behavior of the pillar. There is a gradient feature in the internal deformation of the pillar from the shallow surface to the core. If the rockbolt density meets the strain demand, then rockbolts can delay the inward expansion of cracks by generating local constraints and can effectively fix the spalling rock blocks. With increasing support pressure, the CA and KERR exhibit a decreasing trend and strong power-exponential relationships with support pressure, indicating that there is a transition interval of support pressure and an optimal value for setting the rockbolt density.

PROBIOTIC MICROORGANISMS IN BREAD SOURDOUGHS

The review allows for characterization and evaluation of the typical microbiota and probiotic properties of individual species isolated from various bread sourdoughs. It has been observed that an interest in using sourdoughs for bread making and studying their microbiota has been steadily increasing in recent years. However, an analysis of contemporary publications has revealed insufficient information regarding microorganisms characteristic of sourdoughs based on spelt, buckwheat, corn, rice, teff, amaranth, quinoa, barley, oats, chia, sorghum, beans, and peas. The most studied sourdoughs are those based on wheat and rye flour. A list of the most prevalent lactic acid bacteria (LAB) and yeasts isolated from sourdoughs has been established. It comprises Companilactobacillus paralimentarius, Fructilactobacillus sanfranciscensis, Lactiplantibacillus plantarum, Latilactobacillus sakei, Leuconostoc citreum, Levilactobacillus brevis, Pediococcus pentosaceus, Weissella cibaria, Weissella confusa, as well as Kazachstania humilis, Kazachstania unispora, Pichia kudriavzevii, Pichia fermentans, Saccharomyces cerevisiae and Wickerhamomyces anomalus. All typical mentions of the probiotic properties of microorganisms isolated from bread sourdoughs have been described. When isolating probiotics from bread sourdoughs, special attention should be paid to such species of LAB as Lactiplantibacillus plantarum, Levilactobacillus brevis, Pediococcus pentosaceus, Enterococcus faecium, as well as the yeasts Saccharomyces cerevisiae and Kazachstania humilis, as they are quite commonly found in sourdoughs from various types of flour and have the most conspicuous probiotic properties. According to the review, it has been established that stress tolerance and antimicrobial activity are typical probiotic properties for microorganisms isolated from sourdoughs, although antioxidant properties require further research. Advances in technology and increased economic accessibility will lead to increased demand for new probiotic strains and microorganisms from bread sourdoughs and may help meet new levels of consumer needs.

Reliability index of a pipe transporting hydrogen submitted to seismic displacement

The reliability index was determined for a pipe presenting a corrosion defect, subjected to an internal hydrogen pressure, buried in a soil with a reaction and subjected to displacement due to seismic activity. The results are obtained by calculating the failure condition: strain demand greater than strain resistance, which is usually the basis of local strain-based design (LSBD). From a probabilistic point of view, this condition results from the product of the two probability distributions, Demand and Resistance. The Resistance is assumed to follow a normal distribution. The strain Demand is calculated assuming that the earthquake probability density follows a Gutenberg–Richter distribution. The reliability index is calculated by analytical method. This method is used to predict the reliability index of three different reference periods or seismic zones located in France.

The Influence of Box-Strengthened Panel Zone on Steel Frame Seismic Performance

During the Northridge earthquake, extensive brittle failures on the weld zones of the beam bottom flanges in the rigidity connection of steel special moment frames (SMFs) were detected. One of the primary reasons is the high-tensile strain demand created at the beam bottom flange zones due to positive bending. The weak panel zone of the I-section column exhibits more shear deformation, which promotes and accelerates the brittle fracture of the beam bottom flange weld zones. A box-strengthened panel zone can minimize the shear deformation of the panel zone of the I-section column, which may also reduce the inter-story displacement of steel SMFs and enhance their seismic behavior. In order to investigate this fact, in this research we carried out a model test of a steel frame with a box-strengthened panel zone to examine SMFs’ seismic performance and inter-story displacement, as well as testing the contribution of panel zone shear deformation to inter-story drift. Numerical methods were then used to investigate the influence of the axial compression ratio and beam-to-column linear stiffness ratio on the effect of shear deformation on the box-strengthened panel zone. Design recommendations are given based on the research results.

Association of work-related psychosocial factors and day-to-day home blood pressure variation: the Finn-Home study.

Stress, and particularly job strain, has been found to associate with ambulatory blood pressure (BP). Moreover, BP is known to vary between days. One potential over-looked factor underlying this day-to-day BP variation could be work-related psychosocial factors. Thus, we aimed to study the association between job strain, job demands, job control and day-to-day BP variation. The home BP of 754 regularly working participants (mean age 50.9 ± 4.8, women 51%) of the Finn-Home Study was measured twice in the morning and twice in the evening over seven days. Average SBP and DBP were calculated for each day. Work-related psychosocial factors were measured with survey. Multivariable-adjusted generalized linear models were used for statistical analysis. We found a greater SBP/DBP decrease between weekdays and weekend among participants with high job strain (-1.8 [95% confidence interval, 95% CI, -2.7 to -0.8]/-1.7 [95% CI, -2.3 to -1.1] mmHg) compared to participants with low job strain (-0.7 [95% CI, -1.1 to -0.2]/-0.7 [95% CI, -1.0 to -0.4] mmHg). The participants with high job demands showed a higher BP decrease between weekdays and weekend (-1.4 [95% CI, -2.0 to -0.8]/-1.3 [95% CI, -1.6 to -0.9] mmHg) than the participants with low job demands (-0.5 [95% CI, -1.1 to 0.0]/-0.6 [95% CI, -1.0 to -0.3] mmHg). We did not find BP differences regarding job control. High job strain and high job demands were associated with a greater BP reduction from weekdays to the weekend. Work-related psychosocial factors should be considered when assessing day-to-day BP variation.

Short-time frequency-domain method for truly nonlinear dynamic ground response analysis: The equivalent-nonlinear approach

Evaluating soil nonlinearity during cyclic loading is one of the most significant challenges in ground response analysis, especially when dealing with the inverse problem of deconvolution. Different schemes have already been developed for dynamic ground response analysis, both in the time and the frequency domain. The most accurate method to account for soil nonlinearity is the nonlinear dynamic analysis in the time domain. This approach is based on nonlinear constitutive models capable of accurately simulating highly nonlinear problems like soil liquefaction. However, the time-domain analysis is suitable only for the convolution analysis to define the ground motion at the free surface of a soil deposit from the bedrock motion. The frequency-domain analysis is the most common solution for the inverse problem called deconvolution, which is used to define the bedrock motion from the free surface ground motion. A well-known approach developed in the frequency domain for ground response analysis is the equivalent-linear method (EQL). This approach adopts an iterative procedure to define elastic shear modulus and damping ratio compatible with the induced strain level. Still, it presents some limitations, especially for highly nonlinear soil response, due to the use of strain-compatible but constant soil properties. This article presents a new scheme to conduct truly nonlinear dynamic analysis in the frequency domain based on the new concept of the short-time transfer function. Unlike the EQL method, which uses a constant transfer function, the proposed approach, called the “Equivalent-Nonlinear” method (EQNL), defines a soil transfer function evolving in time, depending on the shear stress and strain demands. The EQNL method approximates the response of a nonlinear system as an incrementally changing viscoelastic system and could represent a valuable tool for nonlinear deconvolution. This article shows the analytical formulation and the first set of validations of the EQNL approach, with detailed comparisons with the EQL and NL methods and vertical array data. These comparisons show the potentialities of the EQNL approach to reproduce the results of the nonlinear dynamic analysis. The EQNL approach has been implemented in MATLAB, and the source code is provided as supplementary material for this article. A more comprehensive validation is underway, aiming to better characterize the limitations and the capabilities of the method.

Overexpression of a membrane transport system MSMEG_1381 and MSMEG_1382 confers multidrug resistance in Mycobacterium smegmatis

Mycobacterium tuberculosis is a leading cause of human mortality worldwide, and the emergence of drug-resistant strains demands the discovery of new classes of antimycobacterial that can be employed in the therapeutic pipeline. Previously, a secondary metabolite, chrysomycin A, isolated from Streptomyces sp. OA161 displayed potent bactericidal activity against drug-resistant clinical isolates of M. tuberculosis and different species of mycobacteria. The antibiotic inhibits mycobacterial topoisomerase I and DNA gyrase, leading to bacterial death, but the mechanisms that could cause resistance to this antibiotic are currently unknown. To further understand the resistance mechanism, using M. smegmatis as a model, spontaneous resistance mutants were isolated and subjected to whole-genome sequencing. Mutation in a TetR family transcriptional regulator MSMEG_1380 was identified in the resistant isolates wherein the gene was adjacent to an operon encoding membrane proteins MSMEG_1381 and MSMEG_1382. Sequence analysis and modeling studies indicated that MSMEG_1381 and MSMEG_1382 are components of the Mmp family of efflux pumps and over-expression of either the operon or individual genes conferred resistance to chrysomycin A, isoniazid, and ethambutol. Our study highlights the role of membrane transporter proteins in conferring multiple drug resistance and the utility of recombinant strains overexpressing membrane transporters in the drug screening pipeline.

Supplementing broiler diets with bacterial selenium nanoparticles enhancing performance, carcass traits, blood indices, antioxidant status, and caecal microbiota of Eimeria tenella-infected broiler chickens

Nanomedicine is a critical therapeutic approach for treating most poultry illnesses, particularly parasitic infections. Coccidiosis is a severe protozoan infection affecting poultry; the emergence of drug-resistant Eimeria strains demands the development of new, safe therapies. Consequently, the objective of this work was to investigate the efficacy of the biosynthesized selenium nanoparticles (SeNPs) byPaenibacillus polymyxa (P. polymyxa) against Eimeria tenella (E. tenella) experimental infection in broiler chickens. The prepared SeNPs absorbed the UV at 270 nm were spherical with a size of 26 nm, and had a surface negative charge of -25 mV. One hundred and fifty, 1-day-old male broiler chicks were randomly allocated into 5 groups (30 birds/group with triplicates each) as follows: T1: negative control (noninfected and nontreated with SeNPs);T2: delivered SeNPs (500 µg/kg diet) for 35 successive days, T3: E. tenella-infected (positive control birds), T4: E. tenella-infected and treated with SeNPs (500 µg/kg diet) and T5: E. tenella-infected chicks and treated with anticoccidial agent (sulfadimidine, 16% solution 8 mL/L of drinking water) for 5 successive days. At 14 d of age, each bird in infected groups was orally treated with 3×103 sporulated oocyst of E. tenella. SeNPs considerably decreased the number of oocysts in broiler feces compared to positive control and anticoccidial drug, followed by a substantial reduction of parasite phase count in the cecum (15, 10, and 8 for meronts, gamonts, and developing oocysts) when compared with positive control birds. The Eimeria experimental infection lowered the activity of antioxidant enzymes, superoxide dismutase (SOD), glutathione peroxidase (GPx), and reduced glutathione (GSH) while increasing the stress parameters nitric oxide (NO) and malonaldehyde (MDA). Moreover, the production of proinflammatory (TNF-α and IL-6) and apoptotic genes (BcL2 and Cas-3) were significantly elevated. Administrating SeNPs to chicks significantly decreased oxidative stress, inflammation, and apoptotic markers in the cecum tissue. Therefore, growth performance, carcass weights, antioxidant enzymes, and blood properties of infected chicks were enhanced. The findings compared the protecting role of Se-nanoparticles against cecum damages in E. tenella-infected broilers.

Digital‐Image‐Correlation for Simulating Cyclic Local Buckling in Steel Beams

AbstractNonlinear continuum finite element (CFE) analyses rely on accurate multiaxial constitutive law formulations along with reliable imperfection patterns for simulating nonlinear geometric instabilities in steel members under mechanical loading. Validations of these models usually rely on conventional measurements of macroscopic parameters (e.g., displacement and strain field). It is common to use global deformation characteristics (e.g., deduced moment versus chord rotation) for model validation purposes of steel members exhibiting inelastic cyclic local buckling. The reason is that measurements from conventional strain gauge readings are not deemed to be reliable well before the onset of local buckling. This is potentially problematic when the accurate prediction of local strain demands is essential. This paper discusses the experimental results from a steel beam instrumented with a digital image correlation (DIC) system and how optical measurements acquired from DIC can be used to benchmark a CFE model representation of this beam. It is shown that while different CFE model types simulate accurately the moment rotation relationship of the steel beam, local strain demand predictions could vary considerably between model types. The results suggest that DIC measurements can inform the selection of proper imperfection patterns to be used in CFE models for the reliable estimation of inelastic strain demands.

Testing of a Novel Induction Heat Treated Steel Brace with Enhanced Buckling Behaviour

AbstractSteel braces are widely used to stabilize steel structures forming horizontal or vertical truss structures; however, their relatively poor buckling behaviour is often lead to overdesigned structures. Induction Heat (IH) treatment technology is a novel contactless material transformation process to effectively strengthen local areas of steel sections. Utilizing IH to increase the strength of the middle length of steel brace sections, buckling behaviour can be improved. The present study experimentally investigates the compression behaviour of the novel braces fabricated by IH‐treated circular hollow steel sections. A Digital Image Correlation (DIC) system is used to measure the experimental deformation quantities, such as axial displacements, out‐of‐plane deformations, and strain distributions along the brace length. Four specimens were tested with two set of different slenderness ratios (λ). Each set includes one conventional steel brace (CSB) and one IH‐treated steel brace (IHSB) with a stronger section at its mid‐length. The specimens were subjected to a monotonic displacement‐controlled loading history until reaching an axial compressive strain of 2.5%. It was found that buckling load can increase up to 20% in IHSBs. IH treatment was also beneficial in improving the post‐buckling behaviour of the brace. The compression strength was found to be more than double in IHSBs than in CSBs at a ductility level of 5 (ductility is defined as the ratio of the target axial displacement to the yielding axial displacement). Moreover, out‐of‐plane displacements were reduced by 28% for the IHSBs at an axial strain of 1% showing a more evenly distribution of strain demands along the brace length.

History of working conditions and the risk of old-age dependency: a nationwide Swedish register-based study.

There is substantial evidence that previous working conditions influence post-retirement health, yet little is known about previous working conditions' association with old-age dependency. We examined job strain, hazardous and physical demands across working life, in relation to the risk of entering old-age dependency of care. Individually linked nationwide Swedish registers were used to identify people aged 70+ who were not receiving long-term care (residential care or homecare) at baseline (January 2014). Register information on job titles between the years 1970 and 2010 was linked with a job exposure matrix of working conditions. Random effects growth curve models were used to calculate intra-individual trajectories of working conditions. Cox regression models with age as the timescale (adjusted for living situation, educational attainment, country of birth, and sex) were conducted to estimate hazard ratios for entering old-age dependency during the 24 months of follow-up (n = 931,819). Having initial adverse working conditions followed by an accumulation throughout working life encompassed the highest risk of entering old-age dependency across the categories (job strain: HR 1.23, 95% CI 1.19-1.27; physical demands: HR 1.36, 95% CI 1.31-1.40, and hazardous work: HR 1.35, 95% CI 1.30-1.40). Initially high physical demands or hazardous work followed by a stable trajectory, or initially low-level physical demand or hazardous work followed by an accumulation throughout working life also encompassed a higher risk of dependency. A history of adverse working conditions increased the risk of old-age dependency. Reducing the accumulation of adverse working conditions across the working life may contribute to postponing old-age dependency.

Numerical assessment of an enhanced stiffened extended end-plate joint for composite frame structures

This paper presents the numerical assessment of a novel enhanced Bolted Stiffened Extended End-Plate (BSEEP) connection for steel frames with composite beams and H-shaped columns in the strong direction. Strain demand is a critical local response that directly controls rupture initiation, and it is more crucial in composite beams since the neutral axis shifts upwards due to the composite action. The proposed connection, called URBS-BSEEP, employs a reduced section in the beam upper flange to mitigate the strain demand problem and provide a stable and symmetric plastic hinge in the desired location. Nonlinear FEM is employed to study joint cyclic behavior. Eleven specimens are designed to compare the proposed connection with existing configurations and to investigate the effects of the slab isolation from the column, shear stud removal, reduced section geometry, and slab thickness. Hysteresis curves, ductilities, failure modes, strain profiles, and energy dissipation capacities are compared. The results indicate the superior performance of the connection compared to the conventional counterparts.