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51.
Amit K. Gupta Harish Manoj K. Rai Mahendra Phulwaria Tanvi Agarwal N. S. Shekhawat 《Applied biochemistry and biotechnology》2014,173(6):1481-1494
The present study described an improved and reproducible in vitro regeneration system for Terminalia arjuna using nodal segment explants obtained from a mature plant. Shoot tips excised from in vitro proliferated shoots were encapsulated in 3 % sodium alginate and 100 mM CaCl2?2H2O for the development of synthetic seeds which may be applicable in short-term storage and germplasm exchange of elite genotype. Shoot multiplication was significantly influenced by a number of factors, namely types and concentrations of plant growth regulators, medium composition, repeated transfer of mother explants, subculturing of in vitro regenerated shoot clumps, agar concentrations, and temperature. Maximum numbers of shoots (16.50?±?3.67) were observed on modified Murashige and Skoog (MMS) medium containing 0.5 mg l?1 of benzylaminopurine (BAP) and 0.1 mg l?1 of naphthalene acetic acid (NAA). To shortening the regeneration pathway, rooting of micropropagated shoots under in vitro condition was excluded and an experiment on ex vitro rooting was conducted and it was observed that the highest percentage of shoots rooted ex vitro when treated with indole-3-butyric acid (IBA, 250 mg l?1)?+?2-naphthoxy acetic acid (NOA, 250 mg l?1) for 5 min. The well-developed ex vitro rooted shoots were acclimatized successfully in soilrite under greenhouse conditions with 80 % survival of plants. Randomly amplified polymorphic DNA (RAPD) analysis confirmed that all the regenerated plants were genetically identical to the mother plant, suggesting the absence of detectable genetic variation in the regenerated plantlets. To the best of our knowledge, this is the first report on synthetic seed production as well as ex vitro rooting and genetic fidelity assessment of micropropagated shoots of T. arjuna. 相似文献
52.
Response surface methodology (RSM) was employed for optimization of medium components and cultural parameters in cost effective
cane molasses based medium for attaining high yield of succinic acid. The important factors obtained by “one-variable-at-a-time-approach”
(cane molasses, corn steep liquor, sodium carbonate, and inoculum density) were further optimized by RSM. The optimum values
of the parameters obtained through RSM (cane molasses 12.5%, corn steep liquor 7.5%, and sodium carbonate 25 mM) led to almost
double yield of succinic acid (15.2 g/l in 36 h) as against “one-variable-at-a-time-approach” (7.1 g/l in 36 h) in 500-ml
anaerobic bottles containing 300-ml cane molasses based medium. Subsequently, in 10-l bioreactor succinic acid production
from Escherichia coli was further improved to 26.2 g/l in 30 h under conditions optimized through RSM. This fermentation-derived succinic acid
will definitely help in replacing existing environmentally hazardous and cost-intensive chemical methods for the production
of succinic acid. 相似文献
53.
Sumit Saxena Archana Asokkumar K Bansi Lal 《Journal of Sol-Gel Science and Technology》2007,41(3):245-248
Terbium Aluminum Garnet (TAG) is an important optically active material and is one of the best materials known for the fabrication
of optical isolators. TAG has a large Verdet constant and has good transmission in the region of 350–1500 nm of the electromagnetic
spectrum. It is also known that TAG melts incongruently at 1840°C. This makes efficient synthesis of TAG important and challenging
and forms the motivation of the present work to develop techniques for the synthesis of TAG at lower temperatures. In the
present work we report the synthesis of TAG using sol-gel techniques following the citrate-nitrate route. The prepared sample
is sintered at various temperatures in presence of air and characterized using X-ray diffraction, FT-IR spectroscopy, energy
dispersive X-ray Analysis and the morphology is observed using the scanning electron microscopy. 相似文献
54.
An electrochemical pathway to prepare circular planar 90Sr/90Y sources for the calibration of surface contamination monitors 总被引:1,自引:0,他引:1
Manoj Kumar Shyamala S. Gandhi J. Nuwad J. Udhayakumar Ashutosh Dash 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(1):709-719
In this communication, we describe a novel method to prepare circular planar 90Sr/90Y sources (? = 16 mm) exploiting the intrinsic properties of the anodized titanium to electro-deposit predicted quantity of 90Sr activity from an aqueous solution. The influences of various experimental parameters such as pH of the electrolyte, applied current density, electrodeposition time and carrier strontium concentration were thoroughly investigated to arrive at a condition resulting optimal deposition of the 90Sr/90Y activity on the substrate. An optimized electrochemical procedure to prepare ~3.7 MBq (~0.1 mCi) of circular planar 90Sr/90Y sources commensurate with regulatory safety requirement has been the positive outcome. 相似文献
55.
Prapti Saxena Sankar P. Sanyal 《Physica E: Low-dimensional Systems and Nanostructures》2004,24(3-4):244-248
We report a detailed study of the phonon properties of hexagonal boron nitride (BN) monolayers as well as nanotubes by using De Launay type of angular force model. The force constants used for calculation of phonon dispersion relations of the nanotube are derived from those for the monolayers of hexagonal by employing force constant method. These force constants have been modified to include the effect of curvature of the tubule. The results are then used to derive the phonon dispersion relations for (10,10) BN nanotubes using ‘zone-folding’ method. Calculated phonon modes are in good agreement with the experimental values obtained so far, for (10,10) armchair BN nanotubes. 相似文献
56.
We investigate the unsteady state temperature distribution in human skin where subcutaneous tissues are not present. The mathematical model is employed for a onedimensional unsteady state case, taking the blood mass flow rate and metabolic heat generation variable with respect to the position in the dermis. The metabolic heat generation depends on the tissue temperature. The thermal conductivity is taken constant but different in two layers. The problem has been solved using Laplace transform and Bessel functions. Numerical results for a simple case are discussed. 相似文献
57.
The problem of recognizing cover-incomparability graphs (i.e. the graphs obtained from posets as the edge-union of their covering and incomparability graph) was shown to be NP-complete in general [J. Maxová, P. Pavlíkova, A. Turzík, On the complexity of cover-incomparability graphs of posets, Order 26 (2009) 229-236], while it is for instance clearly polynomial within trees. In this paper we concentrate on (classes of) chordal graphs, and show that any cover-incomparability graph that is a chordal graph is an interval graph. We characterize the posets whose cover-incomparability graph is a block graph, and a split graph, respectively, and also characterize the cover-incomparability graphs among block and split graphs, respectively. The latter characterizations yield linear time algorithms for the recognition of block and split graphs, respectively, that are cover-incomparability graphs. 相似文献
58.
Hard sphere diameters of liquid alkali metal alloys (Na-Cs and K-Rb) are calculated at 373 K ensuring the minimum Helmholtz
free energy of the system. These diameters are then used to fix the packing density of the alloy. On alloying, the hard sphere
diameters of Na in Na-Cs and K in K-Rb alloys expand whereas those of Cs and Rb contract. 相似文献
59.
A. W. Carbonari J. Mestnik-Filho R. N. Saxena H. Saitovitch 《Hyperfine Interactions》2001,133(1-4):77-81
Magnetic hyperfine fields (mhf) at 111Cd and 140Ce nuclei, dilutely substituting the In and Ce sites, respectively, have been measured in the intermetallic compound CeIn3 using perturbed angular correlation technique. A pure electric quadrupole interaction with an axially symmetric electric field gradient was observed at 111In(EC)111Cd probe nuclei at room temperature while a combined magnetic dipole and electric quadrupole interaction is observed below 10K. Below the ordering temperature, only a magnetic interaction is observed at 140La(–)140Ce probe. The values of mhf measured experimentally as a function of temperature are discussed in terms of critical behavior. 相似文献
60.
S Kailas A Navin A Chatterjee P Singh A Saxena D M Nadkarni D C Biswas R K Choudhury S S Kapoor 《Pramana》1993,41(4):339-344
The measurements of fission fragment angular distributions for the system19F+232Th have been extended to the sub-barrier energies of 89.3, 91.5 and 93.6 MeV. The measured anisotropies, within errors are
nearly the same over this energy region. However, the deviation of the experimental values of anisotropies from that of standard
statistical model predictions increases as the bombarding energy is lowered. 相似文献