Heat Priming of Lentil (Lens culinaris Medik.) Seeds and Foliar Treatment with γ-Aminobutyric Acid (GABA), Confers Protection to Reproductive Function and Yield Traits under High-Temperature Stress Environments

Gradually increasing temperatures at global and local scales are causing heat stress for cool and summer-season food legumes, such as lentil (Lens culinaris Medik.), which is highly susceptible to heat stress, especially during its reproductive stages of development. Hence, suitable strategies are needed to develop heat tolerance in this legume. In the present study, we tested the effectiveness of heat priming (HPr; 6 h at 35 °C) the lentil seeds and a foliar treatment of γ-aminobutyric acid (GABA; 1 mM; applied twice at different times), singly or in combination (HPr+GABA), under heat stress (32/20 °C) in two heat-tolerant (HT; IG2507, IG3263) and two heat-sensitive (HS; IG2821, IG2849) genotypes to mitigate heat stress. The three treatments significantly reduced heat injury to leaves and flowers, particularly when applied in combination, including leaf damage assessed as membrane injury, cellular oxidizing ability, leaf water status, and stomatal conductance. The combined HPr+GABA treatment significantly improved the photosynthetic function, measured as photosynthetic efficiency, chlorophyll concentration, and sucrose synthesis; and significantly reduced the oxidative damage, which was associated with a marked up-regulation in the activities of enzymatic antioxidants. The combined treatment also facilitated the synthesis of osmolytes, such as proline and glycine betaine, by upregulating the expression of their biosynthesizing enzymes (pyrroline-5-carboxylate synthase; betaine aldehyde dehydrogenase) under heat stress. The HPr+GABA treatment caused a considerable enhancement in endogenous levels of GABA in leaves, more so in the two heat-sensitive genotypes. The reproductive function, measured as germination and viability of pollen grains, receptivity of stigma, and viability of ovules, was significantly improved with combined treatment, resulting in enhanced pod number (21–23% in HT and 35–38% in HS genotypes, compared to heat stress alone) and seed yield per plant (22–24% in HT and 37–40% in HS genotypes, in comparison to heat stress alone). The combined treatment (HPr+GABA) was more effective and pronounced in heat-sensitive than heat-tolerant genotypes for all the traits tested. This study offers a potential solution for tackling and protecting heat stress injury in lentil plants.     

A powerful approach to develop nitrogen-doped graphene sheets: theoretical and experimental framework

Journal of Materials Science - We have reported a novel route to develop highly conductive graphene sheets using camphor as a natural precursor followed by nitrogen doping via low-temperature...     

Cd(Zn,S)Se quaternary thin films for electrochemical photovoltaic cell application

In this study, Cd_1−xZn_xS_ySe_1−y (0 ≤ x = y ≤ 0.35) photoelectrodes are deposited via inexpensive facile chemical bath deposition. The effects of Zn and S doping on the compositional, microstructural, electrical, and optical properties of thin films were analysed. The electrochemical photovoltaic (EPV) cell of configuration Cd_1−xZn_xS_ySe_1−y/0.25M sulfide/polysulfide/C was assembled to examine the different performance parameters in light and in dark conditions. An EPV cell fabricated with the Cd_1−xZn_xS_ySe_1−y (0 ≤ x = y ≤ 0.075) photoelectrode exhibited a maximum photoconversion efficiency of 3.18%. This performance can be attributed primarily to the enhanced light-absorption ability of the material because of the enhanced rough microstructure and low recombination of photo-injected electrons with the electrolyte. The photovoltaic (PV) performance is significantly enhanced after doping CdSe with Zn and S.     

Systemic exposure of Paracetamol (acetaminophen) was enhanced by quercetin and chrysin co-administration in Wistar rats and in vitro model: risk of liver toxicity

Intestinal P-glycoprotein (P-gp) and drug-metabolizing enzymes (DMEs) play an important role in the first-pass-metabolism (FPM) and pharmacokinetics (PK) of majority of drugs. Paracetamol is primarily metabolized by conjugation reactions and a little amount (～15%) undergoes cytochrome P450 (CYP2E1)-mediated oxidative metabolism produces a hepatotoxic metabolite, N-acetyl-p-benzoquinonimine (NAPQI). Quercetin and chrysin are naturally occurring flavonoids, reported as modulators of P-gp and DMEs. Therefore, the objective of this study was to evaluate the effects of quercetin and chrysin on the pharmacokinetics of paracetamol using rats and non-everted gut sacs in vitro. Paracetamol was given orally (100?mg/kg) to rats alone and in combination with quercetin (5, 10 and 20?mg/kg) and chrysin (50, 100 and 200?mg/kg) once daily for 21 consecutive days. Blood samples were collected on the 1st day in single dose pharmacokinetic study (SDS) and on the 21st day in multiple pharmacokinetic studies (MDS). The plasma concentrations of paracetamol were determined by HPLC and PK parameters were calculated by using Kinetica (Version 5.1). The maximum plasma concentration (C_max) and area under the curve (AUC_0–12) of paracetamol was significantly increased by quercetin and chrysin co-administration in SDS and MDS. In non-everted rat gut sac method, the absorption of paracetamol was increased by presence of P-gp inhibitors (verapamil, quinidine and ketoconazole), quercetin and chrysin (50?μg/mL). Our findings suggested that the quercetin and chrysin might be inhibited the P-gp and metabolism of paracetamol; thereby increased the systemic exposure of paracetamol. Further studies are needed to evaluate whether the quercetin or chrysin are involved in the formation of NAPQI by CYP2E1 or not on isolated rat hepatocytes or using cell lines.     

Studies on influence of reflux time on synthesis of nanocrystalline TiO2 prepared by peroxotitanate complex solutions

Aqueous peroxotitanate complex (PTC) precursor was used to obtain phase pure anatase nanocrystaline TiO₂. A wet chemical synthesis route was used in which number of aqueous solutions of PTC was refluxed for different time intervals to study the effect of reflux time on final product. Several characterization techniques were used such as DSC–TGA, XRD, UV–Vis, SEM and TEM. The study revealed that there is a significant influence of reflux time on structural, morphological and optical properties of TiO₂. As reflux time of PTC has been increased, crystallite size found to be increased. Also, surface morphology of TiO₂ nanoparticles changed from ‘hexagonal shape’ to ‘rice like’ shape and further in ‘ellipsoid rod like’ shape. Optical band gap energy and refractive index incurred to be altered with respect to reflux time of PTC. Detailed study of refluxed PTC solutions has been reported for the first time in the literature.     

Fluorescent Nucleoside Analogs: Probes for Investigating Nucleic Acid Structure and Function

Base-modified fluorescent nucleoside analog probes have been very valuable in the study of nucleic acid structure and function. Many of them structurally resemble natural bases, and also display useful properties, such as large Stokes shifts and sensitivity to microenvironment changes. Therefore, unlike traditional fluorescence probes, which mostly report global changes, nucleoside analogs, when incorporated into oligonucleotides, can photophysically report changes that occur around the site of interest, at the nucleotide level. In this review, we provide an overview of various strategies that have been employed to design base-modified fluorescent nucleoside analogs. Then we review recent developments and applications of new generation fluorescent nucleoside analogs with a particular focus on the synthesis, photophysical characterizations and applications of heterobicycle-conjugated pyrimidine nucleoside analogs that have been developed by our group. These analogs, which have a minimal effect on the structures of the oligonucleotides into which they are incorporated, show emission in the visible region and excellent fluorescence solvatochromism. Notably, unlike the majority of fluorescent nucleoside analogs developed so far, these analogs retain their fluorescence efficiency when incorporated into oligonucleotides. We anticipate that these nucleoside analogs, with such photophysical properties, would be useful in designing robust biophysical assays to study nucleic acids.     

Metal‐Organic Polyhedra: Catalysis and Reactive Intermediates

The catalytic nature of self‐assembled metal‐organic polyhedra gives an entirely new dimension to the reactivity and properties of molecules within a well‐defined confined space. Encapsulation of a range of guests brings about not only host‐guest interactions but also gives rise to unusual reactivities with selectivity and stabilization of various reactive intermediates. This review briefly covers the synthesis of self‐assembled metal‐organic polyhedra and elaborates their influence in different chemical reactions as well as in the stabilization of unstable chemical species.

     

Driving an Ecological Agenda with Project-Led Research

Here Hugh Whitehead, Irene Gallou, Harsh Thapar, Giovanni Betti and Salmaan Craig of the Specialist Modelling Group (SMG) at Foster + Partners directly address the underlying premise behind the issue. They argue the case for the architect as generalist or ‘centralised controller’, coordinating an often specialised and diverse collaborative design team. As an in-house consultancy within Foster + Partners, SMS provides expertise in complex geometry, computer programming, parametric design and rapid prototyping and environmental simulation, aiming to provided directed specialist support whenever required. Copyright © 2011 John Wiley & Sons, Ltd.     

Single step electrosynthesis of Cu2ZnSnS4 (CZTS) thin films for solar cell application

The Cu₂ZnSnS₄ (CZTS) thin films have been electrodeposited onto the Mo coated and ITO glass substrates, in potentiostatic mode at room temperature. The deposition mechanism of the CZTS thin film has been studied using electrochemical techniques like cyclic voltammetery. For the synthesis of these CZTS films, tri-sodium citrate and tartaric acid were used as complexing agents in precursor solution. The structural, morphological, compositional, and optical properties of the CZTS thin films have been studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), EDAX and optical absorption techniques respectively. These properties are found to be strongly dependent on the post-annealing treatment. The polycrystalline CZTS thin films with kieserite crystal structure have been obtained after annealing as-deposited thin films at 550 in Ar atmosphere for 1 h. The electrosynthesized CZTS film exhibits a quite smooth, uniform and dense topography. EDAX study reveals that the deposited thin films are nearly stoichiometric. The direct band gap energy for the CZTS thin films is found to be about 1.50 eV. The photoelectrochemical (PEC) characterization showed that the annealed CZTS thin films are photoactive.     

Surfactant mediated growth of ZnO nanostructures and their dye sensitized solar cell properties

Single crystalline and highly aligned ZnO nanorods, faceted microrods, nanoneedles and nanotowers were grown onto glass substrates by a facile aqueous chemical method at relatively low temperature (90 °C). Various structure directing agents or organic surfactants such as diaminopropane (DAP), polyacrylic acid (PAA) and polyethylenimine (PEI) were used to modify the surface morphology. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical absorption. It was found that, vertically aligned ZnO nanorods formation takes place with preferential orientation along (002) plane. The organic surfactants play an important role in modifying the morphology. The samples were further used to fabricate dye sensitized solar cells. The highest photocurrent (670 μA) and efficiency were observed for the ZnO:PEI sample.