Synthesis and photoluminescence studies on catalytically grown Zn1 – xMnxS nanowires

Zn1 – xMnxS alloy nanowires with composition (x = 0.0, 0.1 and 0.3) have been successfully synthesized by a simple thermal evaporation on the silicon substrate coated with a gold film of 2 nm thickness. X-ray powder diffraction measurements reveal that as synthesized products were hexagonal wurtzite structure. The as grown nanowires have been investigated by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive Analysis of X-rays (EDAX) and photoluminescence studies. The results reveal that the as grown nanowires consist of Zn, Mn, and S material and diameter ranging from 70 - 150 nm with lengths up to several tens of micrometers. Photoluminescence studies on Zn1 – xMnxS exhibited peaks at 600 and 613 nm for x = 0.1 and 0.3 respectively. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/1053

Fabrication Of ZnxCd1 – xSe Nanowires By CVD Process And Photoluminescence Studies

ZnxCd1 – xSe alloy nanowires with composition x = 0.2, 0.5 have been successfully synthesized by a simple thermal evaporation on the silicon substrate coated with a gold film of 20 Å thickness. The as-synthesized alloy nanowires, 70 - 150 nm in diameter and several tens of micrometer in length. The nanowires are single crystalline revealed from Transmission electron microscopy (TEM) and XRD measurement. The structure of ZnxCd1 – xSe nanowires are hexagonal wurtzite with [01-10] growth direction. Energy gap of the ZnxCd1 – xSe nanowires are determined from micro photoluminescence measurements. The energy gap increases with increasing Zn concentration. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/954

Transcriptome profiling, physiological, and biochemical analyses provide new insights towards drought stress response in sugar maple (Acer saccharum Marshall) saplings

Sugar maple (Acer saccharum Marshall) is a temperate tree species in the northeastern parts of the United States and is economically important for its hardwood and syrup production. Sugar maple trees are highly vulnerable to changing climatic conditions, especially drought, so understanding the physiological, biochemical, and molecular responses is critical. The sugar maple saplings were subjected to drought stress for 7, 14, and 21 days and physiological data collected at 7, 14, and 21 days after stress (DAS) showed significantly reduced chlorophyll and Normalized Difference Vegetation Index with increasing drought stress time. The drought stress-induced biochemical changes revealed a higher accumulation of malondialdehyde, proline, and peroxidase activity in response to drought stress. Transcriptome analysis identified a total of 14,099 differentially expressed genes (DEGs); 328 were common among all stress periods. Among the DEGs, transcription factors (including NAC, HSF, ZFPs, GRFs, and ERF), chloroplast-related and stress-responsive genes such as peroxidases, membrane transporters, kinases, and protein detoxifiers were predominant. GO enrichment and KEGG pathway analysis revealed significantly enriched processes related to protein phosphorylation, transmembrane transport, nucleic acids, and metabolic, secondary metabolite biosynthesis pathways, circadian rhythm-plant, and carotenoid biosynthesis in response to drought stress. Time-series transcriptomic analysis revealed changes in gene regulation patterns in eight different clusters, and pathway analysis by individual clusters revealed a hub of stress-responsive pathways. In addition, qRT-PCR validation of selected DEGs revealed that the expression patterns were consistent with transcriptome analysis. The results from this study provide insights into the dynamics of physiological, biochemical, and gene responses to progressive drought stress and reveal the important stress-adaptive mechanisms of sugar maple saplings in response to drought stress

Banana-shaped mesogens derived from 2,7-dihydroxynaphthalene and 1,3-dihydroxybenzene: novel columnar mesophases

The synthesis and mesomorphic properties of a number of compounds belonging to different homologous series and derived from 2,7-dihydroxynaphthalene are described. In addition, several compounds derived from 1,3-dihydroxybenzene have also been synthesized for comparison. All these compounds are relatively stable esters of E-p-n-alkoxycinnamic acids and E-p-n-alkoxy-α-methylcinnamic acids which are incorporated in the arms of these bent-core compounds. Many of these compounds show interesting mesophases including a novel antiferroelectric columnar phase with a rectangular lattice. Direct transitions from a rectangular columnar B<SUB>1 </SUB>phase, an antiferroelectric B<SUB>2</SUB> phase, and an intercalated B<SUB>6</SUB> phase to a nematic phase have also been obtained. In addition, a direct transition from a novel columnar phase with an oblique lattice to a nematic phase has also been observed for the first time. The X-ray diffraction pattern of an oriented sample of the mesophase with an oblique lattice exhibited by a bent-core material has been reported for the first time. The possibility of a mesophase with a pseudo hexagonal lattice has also been demonstrated in bent-core compounds. The nematic phase has been obtained exclusively in compounds derived from 2,7-dihydroxynaphthalene. The influence of the central core as well as that of a fluorine substituent on the phenyl rings in the sidearms of these bent-core compounds has also been examined. The mesophases have been characterized using conventional techniques

Review article BREEDING FOR TOLERANCE TO STRESS TRIGGERED BY SALINITY IN RICE

ABSTRACT: Rice is one of the world’s most important staple crops. Although rice is considered as a sensitive crop to salinity, it is one of the most widely grown crops in coastal areas. In the present, salinity is the second most widespread soil problem in rice growing countries next to drought and considers as a serious constraint to increased rice production worldwide. Genetic Evaluation and Utilization (GEU) Program at IRRI in 1969 have been screened 138,000 rice genotypes. Of these, 17 % had acceptable tolerance at electrical conductivity (EC) of 10 dS/m at the seedling stage. Traditional cultivars are the most tolerant to abiotic stresses. Cultivars Pokkali, Cheriveruppu, Nona Bokra, SR26B, Damodar and Getu are tolerant of salinity but possess poor agronomic characters. There exists tremendous variation for salt tolerance within species in rice, providing opportunities to improve crop salt-stress tolerance through genetic means. Some attempts to develop salt-tolerant genotypes were based on highly tolerant traditional rice cultivars i.e. Pokkali and Nona-Bokra (Akbar et al., 1985). Mahsuri which is saline tolerant and introduced from Malaysia. Damodar (CSR 1), Dasal (CSR 2), Getu (CSR 3)

Biaxial smectic A phase in homologous series of compounds composed of highly polar unsymmetrically substituted bent-core molecules

Several compounds belonging to three new series of five-ring banana-shaped esters, which are unsymmetrically substituted with respect to the central phenyl ring, have been synthesised. One of the arms of these bent-core molecules has been terminally substituted with a highly polar cyano group while the other end contains an alkoxy chain. The mesophases exhibited by these compounds have been characterised using a combination of optical polarising microscopy, differential scanning calorimetry and X-ray diffraction studies. These studies indicate that most of the compounds show two smectic A mesophases which have a partial bilayer ordering. Conoscopic experiments clearly reveal that the lower temperature smectic A phase is biaxial in nature. A structural model has been proposed for the lower temperature biaxial smectic A phase. It is argued that quartets of molecules, which are conducive to the formation of the biaxial phase, can form in the layers. The in-layer birefringence of the biaxial smectic A phase has also been measured as a function of temperature for one of the compounds

Biaxial smectic A liquid crystal in a pure compound

The synthesis and characterisation is reported of a low molecular weight organic compound to exhibit the biaxial smectic A (SmAb) phase, which shows a transition from the partial bilayer uniaxial SmAd phase to the SmAdb phase as the temperature is lowered