The environment of the Straits of Malacca receives pollution as a result of various industrial and anthropogenic sources, making systematic studies crucial in determining the prevailing water ...quality. Present study concerns concentrations of natural radionuclides and heavy metals in marine fish (Rastrelliger kanagurta) collected from the Straits of Malacca, since aquatic stock form an important source of the daily diet of the surrounding populace. Assessment was made of the concentrations of key indicator radionuclides (226Ra, 232Th, 40K) and heavy metals (As, Mn, Fe, Cr, Ni, Zn, Cu, Co, Sr, Al, Hg and Pb) together with various radiation indices linked to the consumption of seafish. The annual effective dose for all detected radionuclides for all study locations has been found to be within UNSCEAR acceptable limits as has the associated life-time cancer risk. The overall contamination of the sampled fish from heavy metals was also found to be within limits of tolerance.
The majority of COVID-19 survivors experience long-term neuropsychiatric symptoms such as fatigue, sleeping difficulties, depression and anxiety. We propose that neuroimmune cross-talk via ...inflammatory cytokines such as interleukin-6 (IL-6) could underpin these long-term COVID-19 symptoms. This hypothesis is supported by several lines of research, including population-based cohort and genetic Mendelian Randomisation studies suggesting that inflammation is associated with fatigue and sleeping difficulties, and that IL-6 could represent a possible causal driver for these symptoms. Immune activation following COVID-19 can disrupt T helper 17 (TH17) and regulatory T (Treg) cell responses, affect central learning and emotional processes, and lead to a vicious cycle of inflammation and mitochondrial dysfunction that amplifies the inflammatory process and results in immuno-metabolic constraints on neuronal energy metabolism, with fatigue being the ultimate result. Increased cytokine activity drives this process and could be targeted to interrupt it. Therefore, whether persistent IL-6 dysregulation contributes to COVID-19-related long-term fatigue, sleeping difficulties, depression, and anxiety, and whether targeting IL-6 pathways could be helpful for treatment and prevention of long COVID are important questions that require investigation. This line of research could inform new approaches for treatment and prevention of long-term neuropsychiatric symptoms of COVID-19. Effective treatment and prevention of this condition could also help to stem the anticipated rise in depression and other mental illnesses ensuing this pandemic.
•Long COVID symptoms include fatigue, sleeping difficulties, depression and anxiety.•These symptoms may arise from effects of interleukin 6 (IL-6) on the brain.•Cytokine driven immuno-metabolic constraints on neuronal energy metabolism can cause fatigue.•Anti-IL-6 treatment reduces severe complications and mortality in COVID-19 patients.•IL-6/IL-6R pathway could be a target for treatment and prevention of long COVID.
•Quantitative evaluation of parameters affecting capacity of core drilled columns.•Experimental testing of core drilled columns.•Finite element modeling of capacities of lab-scale core drilled ...columns.•Developing quantitative generalized graphical guidelines for safe core size.
Infrastructures which are constructed with inadequate quality control and design requirements or are later being subjected to different usage away from its intended purpose are vulnerable to premature structural failure. A proper detailed engineering assessment (DEA) becomes immensely important when a structure falls in this hazard category in order to determine possible modes of retrofitting. Evaluation of in-situ concrete strength through drilling cores is considered as a relatively precise and reliable mean of obtaining material property for DEA. However, the negative impact of extracting cores on structural components has seldom been addressed in previous studies, thereby causing concerns for engineers. The effect is more prominent for low-strength structures which are usually the case for vulnerable structures requiring assessment. Hence, a study has been undertaken to obtain a quantitative evaluation of parameters affecting the capacity of columns subjected to core extraction. Several parameters, such as column size, compressive strength, lateral tie spacing, core dimension and location have been considered within the study. Finite element models, being validated by comparison with capacities of lab-scale core drilled columns, have been used to analyse the effect of these parameters on column strength. The obtained significant influence of each parameter on column performance has been utilized in developing quantitative generalized graphical guidelines. The graphical guidelines will aid practicing engineers in selecting specific core sizes coherent with other structural parameters obtained from drawings or site visit while abiding by the determined safety limit.
The association between sexual and physical abuse and subsequent depression is well-established, but the associations with specific depressive symptoms and sex differences remain relatively ...understudied. We investigated the associations of sexual and physical abuse with depressive symptoms in men and women in a large population cohort.
Observational study based on 151,396 UK Biobank participants. Exposures included self-reported experiences of childhood physical abuse and sexual abuse. Mid-life outcomes included current depressive symptoms score, individual depressive symptoms, and lifetime depression. We used logistic regression to test associations of childhood sexual/physical abuse with depressive outcomes.
Recalled childhood sexual and physical abuse were both associated with current depressive symptoms score in adults. Results for individual symptoms-based analyses suggest that sexual and physical abuse are associated with all depressive symptoms, particularly suicidal behaviours. The associations between lifetime depression and sexual/physical abuse were not fully explained by current depressive symptoms score, indicating that these findings may not be fully attributable to recall bias. There was no indication of differential risk for specific depressive symptoms among men and women.
Sexual and physical abuse are robust risk factors for depression/depressive symptoms regardless of sex. Higher risk of suicidal behaviours associated with childhood sexual/physical abuse are of particular concern. Longitudinal research into sex-specific associations for individual depressive symptoms is required.
Alkali-activated mortars (AAMs) are developed incorporating binary/ternary combinations of industrial wastes comprising of fly ash class C (FA-C), fly ash class F (FA-F) and ground granulated blast ...furnace slag (GGBFS) with alkaline reagents and silica sand. The use of high calcium precursors, calcium-based powder form reagents, dry mixing method, and ambient curing with performance characterization based on chemical ratios and fracture properties are some novel aspects of the study. The mechanical (dry density, compressive strength, ultrasonic pulse velocity, elastic modulus, fracture/crack tip toughness and fracture energy), durability (shrinkage/expansion and mass change in water and ambient curing conditions, water absorption and freeze-thaw resistance) and microstructural (SEM/EDS and XRD analyses) characteristics of eight AAMs are investigated. The binary (FA-C + GGBFS) mortars obtained higher compressive strengths (between 35 MPa and 42.6 MPa), dry densities (between 2032 kg/m3 and 2088 kg/m3) and ultrasonic pulse velocities (between 3240 m/s and 4049 m/s) than their ternary (FA-C + FA-F + GGBFS) counterparts. The elastic modulus and fracture toughness for mortars incorporating reagent 2 (calcium hydroxide: sodium sulphate = 2.5:1) were up to 1.7 and five times higher than those with reagent 1 (calcium hydroxide: sodium metasilicate = 1:2.5). This can be attributed to the additional formation of C-S-H with C-A-S-H/N-C-A-S-H binding phases in mortars with reagent 2. Ternary mortars exhibited comparatively lower shrinkage/expansion and initial sorptivity indices than their binary counterparts due to the lower geopolymerisation potential of fly ash class F that facilitated the reduction of matrix porosity. All mortar specimens demonstrated 100% or more relative dynamic modulus of elasticity after 60 freeze-thaw cycles, indicating the damage recovery and satisfactory durability due to probable micro-level re-arrangement of the binding phases. This study confirmed the viability of producing cement-free AAMs with satisfactory mechanical and durability characteristics.
The use of link slab (LS) made of Engineered Cementitious Composite (ECC) in the construction of joint-free bridge deck can meet structural performance requirements and enhance durability to minimize ...life cycle costs. Studies documented in the literature to date have been limited to composite steel-concrete I-deck girder bridges despite their commonly used reinforced concrete (RC) girder counterparts in construction. This paper deals with two span full RC deck girder joint-free bridges with ECC link slab (ECC-LS) constructed and tested under static and fatigue loading up to 1,000,000 cycles at 4 Hz subjected to mean stress level of 40% of girder ultimate load, followed by post-fatigue static loading to failure. Residual load, deflection, moment, rotation, stiffness, and energy absorbing capacity of fatigued bridge specimens are compared with its virgin (non-fatigued) counterparts to assess structural performance. Experimental moment capacities are compared with those obtained from existing analytical equations. The comparative performance of joint-fee bridge with RC deck girder is compared with its composite steel-concrete I-girder counterpart to assess its feasibility of construction.
Alkali-activated binders (AABs) are developed using a dry mixing method under ambient curing incorporating powder-form reagents/activators and industrial waste-based supplementary cementitious ...materials (SCMs) as precursors. The effects of binary and ternary combinations/proportions of SCMs, two types of powder-form reagents, fundamental chemical ratios (SiO2/Al2O3, Na2O/SiO2, CaO/SiO2, and Na2O/Al2O3), and incorporation of polyvinyl alcohol (PVA) fibers on fresh state and hardened characteristics of 16 AABs were investigated to assess their performance for finding suitable mix compositions. The mix composed of ternary SCM combination (25% fly-ash class C, 35% fly-ash class F, and 40% ground granulated blast furnace slag) with multi-component reagent combination (calcium hydroxide and sodium metasilicate = 1:2.5) was found to be the most optimum binder considering all properties with a 56 day compressive strength of 54 MPa. The addition of 2% v/v PVA fibers to binder compositions did not significantly impact the compressive strengths. However, it facilitated mitigating shrinkage/expansion strains through micro-confinement in both binary and ternary binders. This research bolsters the feasibility of producing ambient cured powder-based cement-free binders and fiber-reinforced, strain-hardening composites incorporating binary/ternary combinations of SCMs with desired fresh and hardened properties.
Cement kiln dust, rice husk ash, and their combinations are used variously as stabilizers in different percentages (maximum up to 20%) to develop and evaluate stabilized clayey soils. The influence ...of stabilizer types and dosages on fresh and mechanical properties is evaluated through Atterberg limits, standard Proctor compaction, unconfined compressive strength, splitting tensile strength, modulus of elasticity, and California bearing ratio (CBR) tests. The durability characteristics of 19 developed stabilized soil mixtures are also investigated by studying the influence of water immersion on strength, water sorptivity, and drying shrinkage. Correlations between strength, modulus of elasticity, and CBR are also established. Developed stabilized soil mixtures have shown satisfactory strength and durability characteristics and can be used for low-cost construction to build houses and road infrastructures. The use of locally available soils, rice husk ash, and cement kiln dust (waste from the cement industry) in the production of stabilized soils for such applications can provide sustainability for the local construction industry.
Highlights • Longitudinal studies are needed to understand whether elevated circulating inflammatory markers in acute psychosis are a cause or consequence of illness. • This is one of the first ...longitudinal studies of serum CRP and subsequent risk of schizophrenia. • The findings suggest higher CRP levels in adolescence assessed at age 15/16 are associated with increased risk of schizophrenia at follow-up by age 27 years in a linear, dose-response fashion.
Tensile testing and cyclic tensile loading measurements were performed on heat-treated samples of annealed Ti-2448 and cold-rolled Ti-2448. Quenching from above the β-transus produces an alloy that ...is highly superelastic has ultra-low elastic modulus (10–25GPa) and exhibits hysteresis on loading–unloading cycles. On repeated cycling the strain energy absorbed in each cycle decreases. Annealed Ti-2448 exhibits a stable hysteresis loop. Peaks from the α″ phase are observed in X-ray diffraction (XRD) patterns, thus the material is quite lean in β-stabilising additions. The alloy is shown to be highly unstable when heat-treated. A combination of small angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and X-ray diffraction (XRD) was employed to relate the thermally induced microstructural evolution to the change in mechanical properties. A heat-treatment of 80°C to the cold-rolled material precipitated the ω phase causing embrittlement. Increasing the ageing temperature from 80 to 300°C increased the stiffness, made the elastic regime more linear, and further embrittled the alloy. The low temperature heat-treatments precipitate both ω and α″ phases. A higher temperature ageing treatment at 450°C increased the yield strength to over 1GPa and caused embrittlement, indicating co-precipitation of α and ω phases.
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