A dual-mesh approach to ring-rolling simulations with emphasis on remeshing

In this paper, we present a ring-rolling simulation technique, with emphasis on remeshing capabilities. The technique is based on a dual-mesh approach, in which a finite element analysis model is divided into fine sectors and coarse sectors, and three different kinds of remeshing are used. The first of these, which is obligatory, replaces a coarse sector with a fine sector when the coarse sector approaches a plastic deformation zone. The second and third kinds, which are introduced in this study, respectively involve changing the number of sectors and changing the grid system of the frames used to construct the sectors. These remeshing schemes are discussed in detail, and several applications are utilized to demonstrate their characteristics and capabilities in the dual-mesh approach to ring-rolling simulations.     

In vitro antibacterial and anti-inflammatory properties of seaweed extracts against acne inducing bacteria, Propionibacterium acnes

This study was conducted to evaluate the antimicrobial activities of common seaweeds from the coast of South Korea against the etiologic agents of acne vulgaris. Fifty-seven species of seaweed were screened for potential antimicrobial activity. Methanol extracts of 13 species (22.8%) showed inhibitory effects against Propionibacterium acnes. The aqueous extracts of only two species (3.5%) showed antimicrobial activity. When tested with the agar disk diffusion method, Ecklonia cava, E. kurome, Ishige sinicola, and Symphyocladia latiuscula had the strongest inhibitory effects. However, these four seaweed extracts showed no antibacterial activity against Staphylococcus epidermidis at 5 mg disk-1. The minimum inhibitory concentration (MIC) values of E. cava and E. kurome were both 0.31 mg ml-1 and the MIC values of l. sinicola and S. latiuscula were 0.26 and 0.21 mg ml-1, respectively. Among whole plants of E. cava and E. kurome, extracts of the pinnate blade had the highest inhibitory activity on bacterial growth. In cytotoxicity assays, methanol extracts of E. cava, E. kurome, and I. sinicola showed no effect on cell viability at concentrations of 200 microg ml-1. However, the methanol extracts of S. latiuscula reduced cell viability rates to 50% at the same concentration. Additionally, methanol extracts of E. cava, E. kurome, and I. sinicola potently inhibited the in vitro production of nitric oxide. These results suggest that the methanol extracts from these three species may be useful in the development of therapeutic agents for acne vulgaris. Further investigations to determine the bioactive compound are in progress.     

The viral phoenix: enhanced infectivity and immunity evasion of SARS-CoV-2 variants

SARS-CoV-2 pandemic continues with emergence of new variants of concerns. These variants are fueling the third and fourth waves of pandemic across many nations. Here we describe the new emerging variants of SARS-CoV-2 and why they have enhanced infectivity and possess the ability to evade immunity.

     

Foliar use of TiO2-nanoparticles for okra (Abelmoschus esculentus L. Moench) cultivation on sewage sludge–amended soils: biochemical response and heavy metal accumulation

Considering its richness in organic and inorganic mineral nutrients, the recycling of sewage sludge (SS) is highly considered as a soil supplement in agriculture. However, the fate of hazardous heavy metal accumulation in the crops cultivated in SS amended soils is always a source of concern. Since nanoparticles are widely recognized to reduce heavy metal uptake by crop plants; thus, the present experiment deals with okra (Abelmoschus esculentus L. Moench) cultivation under the combined application of SS and TiO₂-nanoparticles (NPs). Triplicated pot experiments were conducted using different doses of SS and TiO₂-NPs such as 0 g/kg SS (control), 50 g/kg SS, 50 g/kg SS?+?TiO₂, 100 g/kg SS, and 100 g/kg SS?+?TiO₂, respectively. The findings of this study indicated that among the doses of treatment combinations investigated, 100 g/kg SS?+?TiO₂ showed a significant (p?<?0.05) increase in the okra plant yield (287.87?±?4.06 g/plant) and other biochemical parameters such as fruit length (13.97?±?0.54 cm), plant height (75.05?±?3.18 cm), superoxide dismutase (SOD: 110.68?±?3.11 μ/mg), catalase (CAT: 81.32?±?3.52 μ/mg), and chlorophyll content (3.12?±?0.05 mg/g fwt.). Also, the maximum contents of six heavy metals in the soil and cultivated okra plant tissues (fruit, stem, and root regions) followed the order of Fe?>?Mn?>?Cu?>?Zn?>?Cr?>?Cd using the same treatment. Bioaccumulation and health risk assessment indicated that foliar application of TiO₂-NPs significantly reduced the fate of heavy metal accumulation under higher doses of SS application. Therefore, the findings of this study suggested that the combined use of SS and TiO₂-NPs may be useful in ameliorating the negative consequences of heavy metal accumulation in cultivated okra crops.

     

Tissue free water tritium and organically bound tritium in the rice plant acutely exposed to atmospheric HTO vapor under semi-outdoor conditions.

Potted rice plants were exposed to atmospheric HTO in a box outdoors for 1 h at 9 different times from booting to yellow-ripe stages. It is indicated that the leaf TFWT concentration may reach equilibrium within 1 h in clear weather. The plant TFWT concentration decreased at a rapid rate for the first several hours and at a much slower rate thereafter. The decrease till harvest was by factors of 600-95,000 depending on the plant parts and exposure times. The time course of the ear OBT concentration was characterized by the exposure time. After exposure at the booting to heading stages, the leaf OBT concentration decreased rapidly for the first several hours and then very slowly. The plant OBT concentration was initially about 2 orders of magnitude lower, but at harvest an order of magnitude higher, than the TFWT concentration. The OBT concentration in hulled seeds at harvest varied with exposure times by a factor of 70, being highest in the exposure performed at the earlier stage of rapid grain growth. Also in this exposure, the plant total OBT was greatest due to the seed OBT.     

Diffusive transport through compacted Na- and Ca-bentonite

The effect of exchangeable cation — Na⁺ and Ca ²⁺ — on the diffusive transport of I⁻, Sr ²⁺ and ³H (as HTO) in compacted bentonite was examined using a through-diffusion method. Total intrinsic diffusion coefficients, D_i, were determined from the steady-state flux of the diffusants through the clays, and apparent diffusion coefficients, D_a, were obtained from the time lag technique. The clays were compacted to a dry bulk density of 1.3 Mg/m³, and Na-bentonite was saturated with a solution of 100 mol NaCl/m3 and Ca-bentonite with one of 50 mol CaCl₂/m³. The D_i values for all diffusants are 2 to 6 times higher in the Ca- than Na-clay. We attribute this to the larger quasicrystal, or particle, size of Ca- compared to Na-bentonite. Hence, Ca-bentonite has a greater proportion of relatively large pores; this was confirmed by Hg intrusion porosimetry. This means the diffusion pathways in Ca-bentonite are less tortuous than those in Na-bentonite. Moreover, in some cases the effective porosity, or the porosity available for diffusive transport, may be greater in Ca-bentonite. The D_a values are inversely proportional to the distribution coefficients of the diffusants with the clays.