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The computational modeling of fracture, particularly in structures with complex crack topologies, remains challenging due to significant computational costs, especially in simulating two- and three-dimensional brittle fracture. This study presents an efficient phase-field model to address these challenges. By leveraging the user (UMAT) subroutine in ABAQUS and establishing an analogy between the phase-field evolution law and the heat transfer equation, the method efficiently tackles complex fracture problems. The model is verified through analysis of typical 2D and 3D fracture benchmarks with different failure modes, demonstrating accuracy and efficiency compared to experimental and numerical data. Additionally, the model is applied to explore brittle fracture in carbon nanotubes (CNTs)/epoxy nanocomposites, revealing insights into the impact of CNT weight fraction on fracture phenomena prediction. The incorporated CNTs in the matrix are considered uniformly dispersed and randomly oriented. Overall, the developed model and computational implementation show promise for meeting the requirements of structural-level engineering practices. [ABSTRACT FROM AUTHOR]

Structural, electronic, magnetic and thermodynamic properties of TbInZ2 (Z = Cu, Ag, and Au) materials with two types of Heusler regular and inverse structures have been investigated in the framework of density functional theory. The non-magnetic, ferromagnetic and antiferromagnetic states are presented using first principles calculations. We applied the full potential linearized augmented plane waves method implemented in the Wien2k code, and the generalized gradient approximation was used to describe the exchange-correlation potential. The results obtained for the density of states and band structures reveal the metallic character of the studied compounds. The structural properties show that the most stable state for TbInZ2 (Z = Cu, Ag, and Au) compounds is the ferromagnetic state. The magnetic susceptibility and electrical Conductivity as a function of chemical potential are calculated using Perdew-Burke-Ernzerhof generalized gradient approximation. Furthermore, the variations of the lattice parameter, heat capacity, Debye temperature and entropy as a function of temperature have been investigated. [ABSTRACT FROM AUTHOR]

Primary infection with varicella zoster virus (VZV), an exclusively human neurotrophic alphaherpsesvirus, results in varicella, known more commonly as chickenpox. Like other alphaherpesviruses, VZV establishes latency in the sensory ganglia and can reactivate to cause herpes zoster (also known as shingles), a painful and debilitating disease, especially in elderly and immunocompromised individuals. The overall incidence of herpes zoster in Europe and the United States is three per 1000 people, but increases sharply after 60 years of age to 10 per 1000 people. Zostavax® is a vaccine approved by the Federal Drug Administration for the prevention of herpes zoster. Unfortunately, this vaccine reduces the incidence of disease by only 51% and the incidence of post-herpetic neuralgia by 66·5% when administered to those aged 60 and older. Moreover, it is contraindicated for individuals who are immunocompromised or receiving immunosuppressant treatments, although they are at higher risk for herpes zoster compared to immune-competent older individuals. This paper reviews VZV pathogenesis, host responses and current vaccines available to prevent herpes zoster. [ABSTRACT FROM AUTHOR]

A systematic first-principles study is performed to calculate the structural, electronic, dynamical, and thermodynamic properties of alkali halides NaF, NaCl, NaBr, and NaI by means of both full-potential linear augmented plane-wave, and plane wave pseudopotential methods. The obtained structural parameters agree favourably with experimental findings. The calculated band gaps are underestimated by GGA functional compared to experiment. The gap values are improved from the modified Becke-Johnson exchange potential, which gives band gaps in perfect agreement with the measured values. In addition, linear-response approach to the density functional theory is used to derive several quantities such as the Born effective charges, high-frequency dielectric constant, phonon band structure, and phonon density of states. The dynamical properties of Na-based alkali halides are also analysed and discussed. Finally the temperature dependence of various quantities such as the mean-squared displacement, and the heat capacity are computed using the quasi-harmonic approximation. [ABSTRACT FROM AUTHOR]

In this study, cadmium (Cd) accumulation was studied in an experimental aquatic exposure. Mosquitofish (Gambusia affinis) were acutely exposed for 96 h to a high concentration of Cd (12 mg/L) and were chronically exposed to a low concentration of Cd(0.4 mg/L) for 30 days. Cd accumulation profiles differed between the two Cd exposures. The Cd concentation in G. affinis tissues increased linearly during acute exposure. In contrast, chronic exposure presented a biphasic pattern of accumulation, with Cd accumulation increasing until 20 days post-exposure then decreasing by the 30th day of the experiment. Histopathological investigations revealed greater changes in gills, kidney and liver tissues after chronic exposure than those recorded during acute exposure. The changes in gill were characterized by epithelial lifting, total and partial lamellar fusion, epithelial necrosis as well as telangiectasis. Necrosis of epithelial cells of renal tubules, glomerular contraction and reduction of Bowman's space were observed in the kidney tissue of exposed fish. The liver hepatocytes showed cytoplasmic vacuolization with lipid droplets and glycogen accumulation. Desquamation of hepatic tissue, congestion of the hepatic central vein and an increase in sinusoidal space were also observed. The result showed that, although Cd accumulation, following acute and chronic exposure, severely affects vital organs in mosquitofish; G. affinis adapts to continued metal accumulation. We hypothesise that this adaptation occurs through activation of a metal resistance mechanism. [ABSTRACT FROM AUTHOR]

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