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81.
Polyhydroxyalkanoate (PHA) was produced by growing Bacillus circulans (MTCC 8167) in the specific detection medium. The identification of the polymer as PHA was confirmed by fluorescence microscopy. The PHA was purified and characterized using FT-IR. The silver nanoparticles (SNP) were synthesized from AgNO3 in the dispersed colloids of PHA (0.085%) using NaBH4 (sodium borohydrate as reducing agent). The stability was tested using wave length scanning with a UV-Vis spectrophotometer and finally with transmission electron microscopy. The PHA stabilized solution was found to be stable for 30 days as against the low stability of silver nanoparticles (SNP) solution alone. 相似文献
82.
Tetrahydrothiopyrans have been efficiently synthesized in good yields with excellent diastereoselectivity from aldehydes and substituted 5-methylhex-4-ene-1-thiol via (3,5)-thionium-ene cyclization reaction mediated by boron trifluoride etherate. 相似文献
83.
P. Bharali R. Saikia R. K. Boruah R. L. Goswamee 《Journal of Thermal Analysis and Calorimetry》2004,78(3):831-838
Hydrolysis of ZnO in acidic pH provides a facile route for synthesis of layered double hydroxides (LDH) bearing Zn2+ with Cr3+ and Al3+ without having carbonate ion in the inter-layer position. The thermal decomposition of the prepared LDH show that with the increase of Cr3+ content in the system there is an increase in the thermal stability of the compounds. In case of Zn-Cr LDH there is a non-mass loss transition around 420°C. Segregation of parent LDH structure to a bivalent oxide and a spinel takes place in both Zn-Cr and Zn-Al LDH only at temperatures above 550°C.Authors are grateful to Director R. R. L. Jorhat for his kind permission to publish the work, as well as acknowledgement is due to Prof. Herbert Poellmann of University of Halle, Germany for some powder XRD runs. Also, acknowledgement is due to Ministry of Environment and Forests, Govt. of India for some financial assistance. 相似文献
84.
We present a brief analysis on the approximate methods for the determination of gluon distribution from the scaling violation
of proton structureF
2
p
in the low-x limit. In the leading order, a general low-x approximated relation is presented having more accuracy than the
previous methods. Next-to-leading order correction is presented incorporating double-log-approximation. The proposed method
is found to give good agreement with data. It may also be used to discriminate between the sets of gluon distributions in
the low-x. 相似文献
85.
Nabanita Saikia Sanchaita Rajkhowa Ramesh C. Deka 《Journal of computer-aided molecular design》2013,27(3):257-276
The potential biomedical application of carbon nanotubes (CNTs) pertinent to drug delivery is highly manifested considering the remarkable electronic and structural properties exhibited by CNT. To simulate the interaction of nanomaterials with biomolecular systems, we have performed density functional calculations on the interaction of pyrazinamide (PZA) drug with functionalized single-wall CNT (fSWCNT) as a function of nanotube chirality and length using two different approaches of covalent functionalization, followed by docking simulation of fSWCNT with pncA protein. The functionalization of pristine SWCNT facilitates in enhancing the reactivity of the nanotubes and formation of such type of nanotube-drug conjugate is thermodynamically feasible. Docking studies predict the plausible binding mechanism and suggests that PZA loaded fSWCNT facilitates in the target specific binding of PZA within the protein following a lock and key mechanism. Interestingly, no major structural deformation in the protein was observed after binding with CNT and the interaction between ligand and receptor is mainly hydrophobic in nature. We anticipate that these findings may provide new routes towards the drug delivery mechanism by CNTs with long term practical implications in tuberculosis chemotherapy. 相似文献
86.
Palash M. Saikia 《Journal of Dispersion Science and Technology》2013,34(1):33-37
The acid base equilibria of the sulfonephthalein dye bromophenol blue (BPB) in aqueous nonionic micellar solutions of Tween 20, Tween 40, Tween 60, and Tween 80 have been investigated spectroscopically using a partition equilibrium method. A visible red shift in the absorbance of the basic form of the dye with increase in surfactant concentration was observed at and above pH 6.98. This has been attributed to the stabilization of the acid form of the dye by the POE groups on the head of the surfactant monomers. Such stabilization effect was found to decreases with decrease in the number of carbon atom in the hydrophobic tail and with the increase in the hydrophile-lipophile balance (HLB) of the surfactant molecule. The equilibrium constant of the partition of the dyes between micellar and aqueous pseudophases (Kass) was found to increase with the surfactants in the order Tween 80 < Tween 60 < Tween 40 < Tween 20. The pKa2 of the dyes were predicted and found to be in good agreement with the experimental values. 相似文献
87.
Baruah Urmilla Borphukan Somip Saikia Maitrayee Saikia Prakash J. Baruah Shashi D. 《Journal of Thermal Analysis and Calorimetry》2021,143(4):3093-3105
Journal of Thermal Analysis and Calorimetry - Efficient incorporation of polar monomers in polyolefin can lead to many desirable properties in the parent chain. Herein, we report the synthesis of... 相似文献
88.
This paper contains the plasma maser interaction between high frequency nonresonant whistler R-mode and low frequency resonant
ion acoustic mode in a relativistic plasma. It shows that the whistler R-mode grows through the plasma maser interaction between
the relativistic electrons and the ion acoustic fluctuation.
相似文献
89.
Partha Pratim Saikia 《Tetrahedron letters》2009,50(12):1328-47
A short and efficient synthesis of 1-deoxy-5-hydroxy sphingolipid is described. The key steps involved are a Jacobsen hydrolytic kinetic resolution (HKR) and Shibasaki’s asymmetric Henry reaction. 相似文献
90.
Prakash J. Saikia Jung Min Lee Byung H. Lee Soonja Choe 《Journal of polymer science. Part A, Polymer chemistry》2007,45(3):348-360
Dispersion polymerization was applied to the controlled/living free‐radical polymerization of styrene with a reversible addition–fragmentation chain transfer (RAFT) polymerization agent in the presence of poly(N‐vinylpyrrolidone) and 2,2′‐azobisisobutyronitrile in an ethanol medium. The effects of the polymerization temperature and the postaddition of RAFT on the polymerization kinetics, molecular weight, polydispersity index (PDI), particle size, and particle size distribution were investigated. The polymerization was strongly dependent on both the temperature and postaddition of RAFT, and typical living behavior was observed when a low PDI was obtained with a linearly increased molecular weight. The rate of polymerization, molecular weight, and PDI, as well as the final particle size, decreased with an increased amount of the RAFT agent in comparison with those of traditional dispersion polymerization. Thus, the results suggest that the RAFT agent plays an important role in the dispersion polymerization of styrene, not only reducing the PDI from 3.34 to 1.28 but also producing monodisperse polystyrene microspheres. This appears to be the first instance in which a living character has been demonstrated in a RAFT‐mediated dispersion polymerization of styrene while the colloidal stability is maintained in comparison with conventional dispersion polymerization. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 348–360, 2007 相似文献