On some liquid crystalline phases exhibited by compounds made of bent-core molecules and their mixtures with rod-like molecules

In most homologous series of compounds made of bent-core (BC) molecules, the B2, B1 and B6 phases occur as the chain length decreases. We have studied binary mixtures of the compound 1,3-phenylene bis[4-(3-methylbenzoyloxy)]4-n-dodecylbiphenyl 4'-carboxylate (BC12) which exhibits the B2 phase with the compound 4-biphenylyl 4'-n-undecyloxybenzoate (BO11) made of rod-like (R) molecules. We find the above sequence of occurrence of the B phases with increasing concentration of BOH. In this paper we describe the physical origin for the formation of these phases in both pure compounds and in the mixtures. We have also found the occurrence of the biaxial smectic A phase when the BO11 concentration is increased to 87-95.5 mol%. We also report on another binary system composed of BC12 and 4-n-octyloxy 4'- cyanobiphenyl (8OCB) made of R molecules. This system exhibits the biaxial smectic A phase down to 30°C. Using polarized infrared spectroscopy we find that the mutual orientation of the R and BC molecules in the SmAdb liquid crystal is such that the arrow axes of the BC molecules are along the layer normal of the partial bilayer smectic structure formed by the rods. We also describe unusual growth patterns obtained when the nematic phase transforms to the SmAdb phase in a mixture with 24 mol% of BC12

Two-dimensionally periodic phases in mixtures of compounds made of rodlike and bent-core molecules

We report two distinct types of two-dimensionally periodic phases in different concentration regions of a binary system composed of the bent-core (BC) compound 1,3-phenylene bis[4-(3-methylbenzoyloxy)]4'-n-dodecylbiphenyl 4'-carboxylate (BC12) and the rodlike (R) compound 4-n-octyloxy 4'-cyanobiphenyl (8OCB). BC12 exhibits only the lamellar B2 phase. 8OCB which has a highly polar cyano end group exhibits the smectic-Ad phase with a lamellar structure of partial bilayers made of antiparallel pairs of the polar molecules. The molecular arrangements in the two-dimensionally periodic phases have been deduced based on optical microscopy, polarized infrared and x-ray diffraction studies. The arrangement in the two-dimensionally periodic phase in lower concentration ranges of BC12 (24 to 35 mol%) is dictated by the partial bilayer structure formed by the rods. The BC molecules arrange themselves with their arrow axes parallel to the long axes of the R molecules and the structure conforms to the c2mm space group symmetry. In higher concentration ranges of BC12 (35 to 60 mol%) the structure is dominated by the BC molecules, to form the familiar B1 phase with the p2mg space group symmetry. The R molecules lie at the interfaces of these domains stabilizing the structure

Interaction Effect of Applied Calcium and Magnesium on Alfisols of Karnataka and its Influence on Uptake and Yield Levels of Tomato (Solanum lycopersium L.)

In a field experiment, interaction effects of applied Ca, Mg and K on yield and quality of tomato and soil nutrient levels was studied in Alfisols of Karnataka. The results showed application of Mg enhanced fruit yield up to 100 kg Mg ha-1 and decreased at higher levels of Mg. The application of Ca also enhanced the yield of tomato but their combined application at different levels had negative effect of one on the other. The results indicated that optimum combination of Mg and Ca was 100 and 250 kg ha-1 respectively for obtaining higher yield in tomato. Soil P content enhanced with application of both Ca and Mg. However, applied Ca and Mg showed significant negative effect on both soil and K content. Interaction effect was however, non-significant on soil pH, EC, OC and Soil N content

A thermotropic biaxial nematic liquid crystal

Optical studies have been carried out on a nematogenic copper complex, which incorporates the features of both rod-like and disk-like molecules. Conoscopic figures are presented demonstrating (i) the occurrence of a biaxial nematic phase in the pure complex, (ii) the uniaxial-biaxial (Na-Nb) transition in binary mixtures, and (iii) the temperature variation of the biaxiality near this transition. The I-Na-Nb phase diagram has been studied for the binary system

Molecular Mechanisms Involved in Biosynthesis and Regulation of Carotenoids in Plants

Carotenoids are coloured compounds beneficial to plants and humans. Some of the major health benefits carotenoids provide include Vitamin A precursors and, antioxidants besides being involved in several physiological functions. Even though several carotenoids are synthesised by plants, only a few like beta/ alpha carotenes and cryptoxanthin serve as Vitamin A precursors. The rest are useful as antioxidants. To draw maximum benefits from carotenoids, we need to incorporate these in crop improvement programmes for enhancing available Vitamin A precursor carotenoids. Therefore, it is essential to study biosynthesis of carotenoids, their genetics and their control. In this review, we focus on factors regulating carotenoid biosynthesis, metabolism and storage in plastids. Transcriptional and genetic control of carotenoid production in plants is discussed in the review using several mutants too. Further, environmental regulation of carotenoid biosynthesis is also highlighted. Carotenoid-rich fruits and vegetables have greater economic value owing to their health-promoting effects. Besides,carotenoids have several industrial applications. Therefore, knowledge of regulation mechanism in carotenoid production in plants can help develop crop varieties or technologies, thus generating carotene-rich fruits and vegetables

Effect of Applied Magnesium on Yield and Quality of Tomato in Alfisols of Karnataka

Field experiments were conducted for two years on Alfisols to assess the effect of applied magnesium on fruit yield and quality parameters in tomato. Magnesium was applied at four levels ranging from 0 to 100 kg/ha in the form of MgSO4. Applied Mg significantly enhanced fruit yield up to 50kg /ha during the two years of experimentation. Tomato quality parameters viz., total titrable acidity, content of lycopene, total carotenoids and ascorbic acid differed significantly among treatments. Applied Mg significantly improved quality. Highest lycopene content, carotenoids and ascorbic acid in the fruit was recorded in Recommended Dose of Fertilizers (RDF) + MgSO4 @ 50Kg/ha followed by RDF + MgSO4 @ 75 kg/ha. Lowest values for the above parameters were observed in the treatment receiving RDF alone in both the years

Re-entrant nematic phase in pure compounds at atmospheric pressure

This article does not have an abstract

A biaxial nematic liquid crystal

We report a biaxial nematic liquid crystal in a simple thermotropic system

Antioxidant, antimicrobial and cytotoxic activity of Curkolin® (Curcuma longa and Coleus forskohlii formulation)

The aim of this study was to screen the in vitro antimicrobial, antioxidant and cytotoxicity effect of Curkolin®, a combination of curcumin and C. forskolin in the ratio 4:1. Curcuma longa L. is the source of curcumin while C. forskohlii has been used in traditional ayurvedic medicine for curing various disorders and therefore the forskolin is the source of the diterpenoids. The medicinal properties of plants are investigated throughout the world for scientific advancement for their important pharmacological activities, user convenient, economically viable with low toxicity. The antioxidant property of Curkolin® was determined to be 55.42 µg/ml using (Diphenyl picryl hydrazine) DPPH assay and was then compared with standard Butylated hydroxytoluene (BHT). The antimicrobial activity was assessed by calculating the MIC and MBC using microplate serial dilution technique. It exhibited 250 µg/ml, the least MIC value of Bacillus cereus as compared to the rest Gram-positive (Streptococcus mutans and Staphylococcus aureus) and Gram-negative (Escherichia coli and Salmonella typhi) bacteria. Further, it was analyzed for cytotoxic screening on MCF-7 breast cancer cell line by MTT assay, which has shown a strong anti-proliferative activity. The IC50 values of Curkolin® were found 135.8 μg/ml. Together these results suggest the combination to be an effective antioxidant, antimicrobial and cytotoxic agent

Breeding tomato (Solanum lycopersicum L.) for resistance to biotic and abiotic stresses

Tomato (Solanum lycopersicum L.) is an important vegetable crop cultivated in the tropical and sub-tropical regions of the world. Low productivity in India is due to occurrence of both biotic and abiotic stresses. Among the biotic stresses, tomato leaf curl disease, bacterial wilt, early blight and Groundnut Bud Necrosis Virus disease have become serious production constraints causing considerable yield loss in the major tomato growing areas of the country. Adoption of multiple disease resistant varieties or F1 hybrids would be the most appropriate way to address these diseases. At ICAR-IIHR, Bengaluru systematic breeding strategies were employed to pyramid genes for resistance to early blight, bacterial wilt and tomato leaf curl diseases and to develop advanced breeding lines& F1 hybrids with triple disease resistance. Stable source of resistance to early blight and bi-partite begomo-virus (Tomato Leaf Curl New Delhi Virus) has been identified in Solanum habrochaites LA-1777. Validation with molecular markers linked to tomato leaf curl virus resistance revealed that LA-1777 carryTy2 and other putative resistant genes. Several high yielding dual purpose hybrids were also developed for fresh market and processing with high level of resistance to multiple diseases. Cherry tomato lines have also been bred for high TSS, total carotenoids, total phenols, flavonoids, vitamin C, acidity and lycopene content. IIHR-249-1, IIHR-2101 (Solanum habrochaites LA-1777), IIHR- 2866 and IIHR-2864 recorded high values for quality parameters like total carotenoids, lycopene, vitamin C, total phenols, flavonoids and TSS. Drought tolerant root stock has been developed by an interspecific cross between S. habrochaites LA-1777 and S. lycopersicum (15 SB SB). Resistant sources have also been identified against Tuta absoluta, a serious insect pest reported from major tomato growing areas in the country in recent time. High temperature tolerant breeding lines are in pipe line