National Chemical Laboratory

About: National Chemical Laboratory is a facility organization based out in Pune, Maharashtra, India. It is known for research contribution in the topics: Catalysis & Nanoparticle. The organization has 8891 authors who have published 14837 publications receiving 387600 citations.

Critical Study of Local Reactivity Descriptors for Weak Interactions: Qualitative and Quantitative Analysis of Adsorption of Molecules in the Zeolite Lattice

Abstract: In the work described in this paper we have studied the adsorption of gaseous molecules inside the zeolite lattice using recently developed different reactivity descriptors. In particular, we have used Fukui function-based descriptors and local hard−soft acid−base (HSAB) principle for a quantitative and qualitative analysis. This represents the first case in which local HSAB principle has been used for quantitative description of weak adsorption cases.

Low temperature synthesis and NOx sensing properties of nanostructured Al-doped ZnO

Abstract: Although ZnO is studied intensively as a sensing material, there are limited reports available on aluminum-doped ZnO (AZO) as a NO x sensor. This paper reports selective NO x sensing characteristics of Al-doped ZnO synthesized in the form of porous pellets sintered at 350 °C. The salient feature of our experimental results is that our sensor can detect small concentrations of NO x at lower operating temperature. It is also observed that as compared to gases such as SO x , HCl, LPG, H 2 S, H 2 , ammonia, alcohol and acetone it selectively detects NO x due to Al-doping. The amount of Al in ZnO during synthesis is varied between 1 and 10 wt%. Our sensor senses NO x concentration as low as 20 ppm at 100 °C with a %response of 11 and a %response of 740 at 300 °C for 1 wt% Al. Of all the compositions with Al-doping, 1 wt% is found to give best results. Sensing experiments carried out at 350 °C, however, do not show any significant improvement in the gas sensing properties. The phase contents and lattice parameters were determined by XRD and the average particle size was obtained using Scherrer formula. A probable mechanism for sensing NO x involving oxygen ion adsorption and desorption on the surface of sensor has been suggested.

Synthesis of a stable gold hydrosol by the reduction of chloroaurate ions by the amino acid, aspartic acid

Abstract: Development of reliable protocols for the synthesis of nanoparticles of well-defined sizes and good monodispersity is an important aspect of nanotechnology In this paper, we present details of the synthesis of gold nanoparticles of good monodispersity by the reduction of aqueous chloroaurate ions by the amino acid, aspartic acid The colloidal gold solution thus formed is extremely stable in time, indicating electrostatic stabilization via nanoparticle surface-bound amino acid molecules This observation has been used to modulate the size of the gold nanoparticles in solution by varying the molar ratio of chloroaurate ions to aspartic acid in the reaction medium Characterization of the aspartic acid-reduced gold nanoparticles was carried out by UV-visible spectroscopy, thermogravimetric analysis and transmission electron microscopy The use of amino acids in the synthesis and stabilization of gold nanoparticle in water has important implications in the development of new protocols for generation of bioconjugate materials

Microsatellite (GATA)n reveals sex-specific differences in Papaya

Abstract: Papaya, an economically important fruit plant, is polygamous in nature. The sex of dioecious papaya plants can be deduced only after they attain reproductive maturity (6–8 months). Normally, 50% of the population in a field is composed of unfruitful male plants and almost 45% of these have to be uprooted at the flowering stage. This unnecessary cultivation of unwanted males leads to wastage of resources, which can be avoided if the sex of the plant is determined at juvenile stage. Morphological and cytological studies conducted so far have failed to differentiate between the various sex forms of papaya. Its dioecious nature, occasional sex-reversal of male flowers and the absence of a heteromorphic pair of sex chromosomes make papaya an interesting system to study sex determination at the molecular level. In the present study, highly informative microsatellite and minisatellite probes were employed to identify sex-specific differences in papaya. Among these, only the microsatellite probe (GATA)4 demonstrated sex-specific differences in all the cultivars analysed. The diagnostic potential of this microsatellite marker was exploited to sex papaya plants at the seedling stage. This study also indicates that the genetic material of the X and Y chromosomes of papaya is diverging in a sex-specific manner and hence they are in the process of differentiation.