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171.
Namita Bansal Chetna Janveja Rupinder Tewari Raman Soni Sanjeev Kumar Soni 《Applied biochemistry and biotechnology》2014,172(1):141-156
Optimization of cultural conditions for enhanced cellulase production by Aspergillus niger NS-2 were studied under solid-state fermentation. Significant increase in yields (CMCase 463.9?±?20.1 U/g, FPase 101.1?±?3.5 U/g and β-glucosidase 99?±?4.0 U/g) were obtained under optimized conditions. Effect of different nutritional parameters was studied to induce the maximum production of cellulase complex. Scale-up studies for enzyme production process were carried out. Characterization studies showed that enzymes produced by A. niger NS-2 were highly temperature- and pH stable. At 50 °C, the half life for CMCase, FPase, β-glucosidase were approximately 240 h. Cellulases from A. niger NS-2 were stable at 35 °C for 24 h over a broader pH range of 3.0–9.0. We examined the feasibility of using steam pretreatment to increase the saccharification yields from various lignocellulosic residues for sugar release which can potentially be used in bioethanol production. Saccharification of pretreated dry potato peels, carrot peels, composite waste mixture, orange peels, onion peels, banana peels, pineapple peels by crude enzyme extract from A. niger NS-2, resulted in very high cellulose conversion efficiencies of 92–98 %. 相似文献
172.
Evaluation of micronuclei induced by energetic electrons delivered at different dose rates per pulse
S. Acharya N. N. Bhat G. Sanjeev Y. Narayana 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(2):993-997
The severity of the cell damage induced by electrons is mainly depends upon absorbed dose and dose rate. This severity of the damage can be analysed by estimating micronuclei frequency in a binucleated cell (MN/BNC), which is a simple, standard and extensively used assay. In the present study, quantification of multiple MN within a cell along with quantification of binucleated cells with micronuclei (BNC with MN), the number of micronuclei per micro-nucleated binucleated cell (MN/(BNC with MN)), percentage of BNC and Nuclear Division Index (NDI) in lymphocytes, exposed to single 2 µs, 500, 50 and 25 ns pulses of 7 MV electrons at various doe rate per pulse from 1 × 106 to 3.2 × 108 Gy s?1, were carried out to assess the cell damage. A comparison study amongst end points, multiple MN, BNC with MN, MN/(BNC with MN), percentage of BNC, NDI and MN/BNC was also made. Present study suggests that the quantification of multiple MN, BNC with MN, MN/(BNC with MN), percentage of BNC and NDI along with MN/BNC provided vital information, while assessing cell damage at high doses and dose rates. 相似文献
173.
174.
Ravi Kumar Thakur Akansha Mishra K.K.G. Ramakrishna Rohit Mahar Sanjeev K. Shukla A.K. Srivastava Rama P. Tripathi 《Tetrahedron》2014
A series of novel nucleoside analogues having dual bases (pyrimidine and triazole) and sugars have been synthesized by CuAAC reaction of azido sugars with propynylated pyrimidines. These compounds were evaluated for their in vitro α-glucosidase inhibitory activity. In this series, compounds 4b, 4d, 8a, 8b, 8c, 8e, 8g, 8h, and 8i exhibited very good inhibition of α-glucosidase enzyme. Nucleoside analogues 8a, 4b, 8h, and 8c displayed 47.4%, 41.8%, 39.4%, and 34.6% inhibition, respectively, comparable to the standard drug acarbose (53.4%). 相似文献
175.
176.
For any ɛ > 0 we give a (2 + ɛ)-approximation algorithm for the problem of finding a minimum tree spanning any k vertices in a graph (k-MST), improving a 3-approximation algorithm by Garg [10]. As in [10] the algorithm extends to a (2 + ɛ)-approximation algorithm for the minimum tour that visits any k vertices, provided the edge costs satisfy the triangle inequality.
Research supported by NSF CAREER award NSF CCR-9502747, NSF grants CCR-0205594 and CCR-0098180, an Alfred Sloan Fellowship,
and a Packard Fellowship.
Research supported by an NSERC Discovery grant. 相似文献
177.
Formation of high nuclearity mixed-valent polyoxovanadates in the presence of copper amine complexes
Jency Thomas Sanjeev Sharma S. E. Lofland K. V. Ramanujachary A. Ramanan 《Journal of Chemical Sciences》2006,118(1):79-86
Two new Müller-type clusters, a one-dimensional solid [Cu(en)]2
4[Cl ⊂V15O36]−12H2O1, and a three-dimensional solid [Cu(pn)]2
4[Cl ⊂V18O42]·12H2O2, have been synthesised by employing identical hydrothermal conditions except varying the nature of organic diamine.1 crystallised in a chiral space groupP212121 witha = 12.757(1),b = 18.927(2) andc = 28.590(3) ?, andZ =4.2 crystallised in a tetragonal system with space groupP4/nnc,a = 15.113(1) andc = 18.542(3) ?, andZ = 2. Mixed-valent vanadium ions in structures1 and2 have been established both by magnetisation and bond-length bond-valence measurements. Chemistry of formation of high nuclearity
polyoxovanadate clusters is discussed.
Dedicated to Prof J Gopalakrishnan on his 62nd birthday. 相似文献
178.
Summary. Replacing the typical lactam β-alkyl substituents of xanthobilirubinic acid and kryptopyrromethenone, two bilirubin analogs
long used as model compounds in studies of its photochemistry and metabolism, leads to increased amphiphilicity. Synthesized
by base-catalyzed condensation of 3,4-dimethoxypyrrolin-2-one with the appropriate pyrrole α-aldehyde, the 2,3-dimethoxyl
analogs of xanthobilirubinic acid and kryptopyrromethenone are yellow-colored dipyrrinones that form intermolecular hydrogen-bonded
dimers in the solid, as determined by X-ray crystallography, and in CHCl3, as revealed by 1H NMR and vapor pressure osmometry. These two new dipyrrinones are approximately ten times more soluble in water than their
parent dipyrrinones. 相似文献
179.
The article presents a design of an optical filter using Photonic Band Gap (PBG) materials in the visible and infrared region of the electromagnetic spectrum. This idea is based on the famous Kronig-Penny model in the band theory of solids. The suggested filter may work at any range of the wavelength that can be achieved by choosing the appropriate values of the controlling parameters. This structure is also able to pass the light emitted by the Ruby laser and this acts as a monochromator. Also, we have studied the anomalous behavior of refractive index for the structure having alternate layers of air and GaAs. 相似文献
180.
We present a randomized procedure for rounding fractional perfect matchings to (integral) matchings. If the original fractional
matching satisfies any linear inequality, then with high probability, the new matching satisfies that linear inequality in
an approximate sense. This extends the well-known LP rounding procedure of Raghavan and Thompson, which is usually used to
round fractional solutions of linear programs.?We use our rounding procedure to design an additive approximation algorithm
to the Quadratic Assignment Problem. The approximation error of the algorithm is εn
2 and it runs in n
O
(log
n
/ε2) time.?We also describe Polynomial Time Approximation Schemes (PTASs) for dense subcases of many well-known NP-hard arrangement
problems, including MINIMUM LINEAR ARRANGEMENT, MINIMUM CUT LINEAR ARRANGEMENT, MAXIMUM ACYCLIC SUBGRAPH, and BETWEENNESS.
Received: December 12, 1999 / Accepted: October 25, 2001?Published online February 14, 2002 相似文献