Mode shapes and frequencies of radially symmetric vibrations of annular sandwich plates of variable thickness

An analysis and numerical results of radially symmetric vibrations of annular sandwich plates with core of linearly varying thickness are presented. The face sheets are treated as membranes of constant thickness, and the core is assumed to be solid as well as moderately thick. Due to linear thickness variation in the core, the face sheets take the shape of a truncated conical shell and because of this the face sheets membrane forces contribute to the bending and transverse shear of the core of the sandwich plate. Keeping this in view, the equations of motion for such a plate are developed by Hamilton’s energy principle. The frequency equations for three different combinations of boundary conditions, namely clamped at the inner edge and clamped or simply supported or free at the outer edge, are obtained by employing the differential quadrature method. The lowest three roots of these frequency equations have been reported as the frequencies for the first three modes of vibration. The effect of various plate parameters such as taper parameter, thickness of the core at the center, face thickness, and radii ratio on the natural frequencies has been analyzed. Three-dimensional mode shapes for a specified plate for all the three boundary conditions are illustrated. A comparison of results is presented.     

Rapid Detection of Wheat Blast Pathogen Magnaporthe oryzae Triticum Pathotype Using Genome-Specific Primers and Cas12a-mediated Technology

Wheat blast, caused by the fungus Magnaporthe oryzae Triticum (MoT) pathotype, is a devastating disease persistent in South America and Bangladesh. Since MoT generally fails to cause visual symptoms in wheat until the heading stage when the infection would have advanced, disease control by fungicide application solely based on the detection of visual symptoms is ineffective. To develop an accurate and sensitive method to detect MoT at the seedling and vegetative stages for disease control, we sequenced the genomes of two MoT isolates from Brazil and identified two DNA fragments, MoT-6098 and MoT-6099, that are present in the MoT genome but not in the genome of the rice-infecting Magnaporthe oryzae Oryzae (MoO) pathotype. Using polymerase chain reaction (PCR), we confirmed the specificity of the two markers in 53 MoT and MoO isolates from South America and Bangladesh. To test the efficiency of the two markers, we first established a loop-mediated isothermal amplification (LAMP) method to detect MoT at isothermal conditions, without the use of a PCR machine. Following this, we used the Cas12a protein and guide RNAs (gRNAs) to target the MoT-6098 and MoT-6099 sequences. The activated Cas12a showed indiscriminate single-stranded deoxyribonuclease (ssDNase) activity. We then combined target-dependent Cas12a ssDNase activation with recombinase polymerase amplification (RPA) and nucleic acid lateral flow immunoassay (NALFIA) to develop a method that accurately, sensitively, and cost-effectively detects MoT-specific DNA sequences in infected wheat plants. This novel technique can be easily adapted for the rapid detection of wheat blast and other important plant diseases in the field.     

Light-Dependent Nitrate Removal Capacity of Green Microalgae

In the present study, Chlamydomonas sp. MACC-216 was used to investigate total nitrate removal in TAP medium with sodium nitrate as the sole nitrogen source under several light conditions made up of permuted combinations of three light colors (referred to as blue, red, and white light) and three light intensities (50 µmol m⁻² s⁻¹, 100 µmol m⁻² s⁻¹, and 250 µmol m⁻² s⁻¹). It was observed that nitrate removal efficiency is influenced by light color as well as light intensity. Additionally, Chlamydomonas sp. MACC-216 was cultivated in synthetic wastewater under four light conditions, namely, Blue 250, Blue 125 + Red 125, Red 250, and White 250, where it showed the highest nitrate removal efficiency and nitrate reductase activity under the Blue 125 + Red 125 light condition. To observe the impact of light color on the nitrate removal capacity of Chlamydomonas sp. MACC-216, the expression of five genes participating in nitrate transport and reduction (NRT1, NRT2.1, NRT2.2, NIA, and MCP) was also analyzed; these genes showed the highest expression under the Blue 125 + Red 125 light condition. Based on the above-mentioned findings, the blue + red light combination emerged as a promising light combination for nitrate removal. Hence, our study suggests the importance of the blue + red light combination together with high light intensity, as the optimal light condition for nitrate removal from synthetic wastewater in comparison to other monochromatic lights with high light intensity.     

Studies on the cure characteristics and vulcanizate properties of 50/50 NR/SBR blend

Blends of 50/50 natural rubber (NR) and styrene-butadiene rubber (SBR) are vulcanized using several conventional and semi-EV systems. The cure characteristics and vulcanizate properties are compared. The quantity and quality of crosslinks in each case are deciphered by chemical probes to correlated them with the vulcanizate properties.     

Acid-base,electron-donating and magnetic properties of Nd2O3 and its mixed oxides with alumina catalysts

The electron donor properties of Nd₂O₃ activated at 300, 500 and 800°C were investigated through studies on the adsorption of electron acceptors of various electron affinities — 7, 7, 8, 8-tetracyanoquinodimethane (2.84 eV), 2, 3, 5, 6-tetrachloro-1, 4-benzoquinone (2.40 eV), p-dinitrobenzene (1.77 eV), and m-dinitrobenzene (1.26 eV) in solvents acetonitrile and 1, 4-dioxan. The extent of electron transfer during adsorption has been found from magnetic measurements and electronic spectral data. The corresponding data on mixed oxides of neodymium and aluminium are reported for various compositions. The acid-base properties of catalysts were also determined using a set of Hammett indicators.     

Fixed-width confidence interval estimation of the inverse coefficient of variation in a normal population

A sequential procedure is developed in order to construct a confidence interval of “fixed-width and preassigned coverage probability” for the inverse of the coefficient of variation of a normal population. The proposed sequential procedure is proved to be “asymptotically efficient and consistent” in the sense of Chow and Robbins ([1]: Ann. Math. Statist. 36, 457–462 (1965)). Asymptotic distribution of the stopping time is derived.     

Modulation of cell growth and apoptosis response in human prostate cancer cells supplemented with tocotrienols

Previous studies have shown that tocotrienols are powerful growth inhibitors and potent inducers of apoptosis in human breast cancer cells. The objective of the current study was to examine effects of tocotrienols on apoptotic signals in androgen‐independent PC‐3 human prostate cancer cells. We investigated the effects of the tocotrienol‐rich fraction (TRF) from palm oil, α‐tocopherol (αT), α‐tocotrienol (αT₃), γ‐tocotrienol (γT₃) and δ‐tocotrienol (δT₃) on PC‐3 cell growth. TRF inhibited PC‐3 growth with a nonlinear response, with complete growth suppression at 10 µg/mL. δT₃ and γT₃ showed complete cell inhibition at 8 µg/mL whilst αT had no effect. δT₃ and γT₃ showed the most promise in the cell growth assays, and all subsequent experiments were performed with δT₃, TRF and αT. TRF and δT₃ at 8 µg/mL induced apoptosis in PC‐3 cells after 48 h of treatment. In addition, TRF and δT₃ treatments were able to affect the cell cycle, with accumulation in the S phase, G2 phase block and increases in SubG1 by 72 h. We then proceeded to investigate the expression levels of Fas receptor and Fas ligand, caspase 8, caspase 3 and bax in PC‐3 cells following treatment with tocotrienols using real‐time PCR and Western blot methods. TRF and δT₃ at 8 µg/mL increased Fas ligand expression levels by 368 and 456%, respectively, after 24 h and Fas receptor expression levels by 210% and 356%, respectively, after 48 h. TRF‐ and δT₃‐treated PC‐3 cells overexpressed caspase 8 and bax protein after 24 h, and caspase 3 after 48 h. In conclusion, tocotrienols are able to induce apoptosis and cell cycle arrest in PC‐3 cells, with increased expression of Fas receptor, Fas ligand, caspase 8, caspase 3 and bax, suggesting a potential role in chemoprevention of prostate cancer.     

On the Mechanisms Governing Aluminum-Mediated Solid-Phase Epitaxy of Silicon

Mechanisms governing the aluminum-mediated solid-phase epitaxy of Si on patterned crystalline Si substrates have been identified by studying the deposited material as a function of growth conditions when varying parameters such as temperature, growth time, and layer-stack properties. Early growth stages can be discerned as first formation of “free” Si at the Al/α-Si interface, then diffusion of Si along the Al grain boundaries, nucleation at the Si substrate surface, nuclei rearrangement, and finally crystal growth. The acquired understanding is applied to control the selectivity and completeness of single-crystal growth in various sizes of contact windows to the Si substrate.     

Evaluation of oxidative stress biomarkers in hepatocytes of grey mullet inhabiting natural and polluted estuaries

The aim of the study was to evaluate the impact of environmental contaminants on oxidative stress biomarkers in hepatocytes of Indian estuarine water grey mullet, Mugil cephalus collected from unpolluted Kovalam and polluted Ennore estuaries. Initially, a comparison was made between the general water chemistry and environmental pollutants like heavy metals to identify the ecotype of the estuaries. Biomarker responses and bioaccumulation of metals were determined along with histological studies of fish hepatocytes to assess contamination impact. Water chemistry data with higher temperature, salinity, pH, biochemical oxygen demand, chemical oxygen demand and low dissolved oxygen and environmental pollutants with higher metal concentration (p < 0.05) were observed at Ennore than Kovalam indicating its polluted environment. A significant increase (p < 0.05) in lipid and protein oxidation markers, decrease (p < 0.05) in thiol status and antioxidant enzyme activities were observed in the Ennore fish hepatocytes compared to Kovalam counterpart. Bioaccumulation of heavy metals was significantly higher (p < 0.05) in fish from Ennore. Hepatocytes from Ennore also featured extensive lipid-type vacuolation, increased size and membrane disruption. All the findings highlighted the value of oxidative stress biomarkers and membrane disruption as the sensitive parameters of environmental pollutant contamination and their importance in biomonitoring of aquatic ecosystems. This is also the first such attempt reported at the cellular level from South India stressing the importance of biomarkers in biomonitoring programmes using fish hepatocytes as the model system.