313 research outputs found
Genetic relatedness among developing seeds and intra fruit seed abortion in Dalbergia sissoo (Fabaceae)
Dalbergia sissoo, a wind-dispersed tropical tree, exhibits high intrafruit seed abortion. Of the four to five ovules in the flower, generally one and occasionally two or three develop to maturity. It has been proposed that the seed abortion is a consequence of intense sibling competition for maternal resources and that this competition occurs as an inverse function of the genetic relatedness among the developing seeds. Accordingly, developing seeds compete intensely when they are genetically less related but tend to develop together when genetically more related. We tested this hypothesis by comparing the genetic similarity among the pairs of seeds developing within a pod with that among (a) random pairs from the pool of all seeds, (b) random pairs from single-seeded pods, and (c) random pairs from two-seeded pods, using both randomly amplified polymorphic DNA (RAPD) and isozymes in five trees. We found that the pairs of seeds developing within a pod are genetically more similar than any random pairs of seeds in a tree. Thus the formation of two-seeded pods appear to be associated with increased genetic relatedness among the developing seeds. We discuss the results in the context of possible fitness advantages and then discuss the possible mechanisms that promote tolerance among related seeds
Studies on crossability in cashew (Anacardium occidentale L.) genotypes
Successful hybridization primarily depends on the crossability of the parents involved as well as development of the F1 hybrids and their derivatives. In the present study, 12 crosses were attempted to study the crossability relationship among cashew genotypes. Among the crosses, the highest crossability was recorded in the cross H-303 x VTH 711/4 (17.16%), whereas, high rate of abscission of young fruits was observed in crosses involving NRCC Selection -2 as female parent. The genotype VTH 711/4 has shown substantially high per cent of crossability and better nut set with different genotypes of cashew
Recent advances in starch–clay nanocomposites
Biological nanocomposites are a valuable addition to the existing nanocomposite materials and eventually can substitute petroleum-based composite materials in numerous applications due to their inherent advantages such as biodegradability, eco-friendliness, low cost, and easy availability to name a few. Recently, polymer–clay nanocomposites have achieved much more attention due to their enhanced properties such as size dispersion and significant enhancement in physicochemical and mechanical properties in comparison to the pure polymer systems. Among various biopolymers, starch is one of the most abundant natural polymers on the earth and is highly valuable due to its chemical and physical properties. Starch polymer has highly increased potential as an alternative to petroleum-based materials. However, starch cannot be used alone and starch–clay nanocomposite has emerged as a new potential green sustainable material. This article focuses on recent progress in starch-based nanocomposites with particular emphasis on starch–clay nanocomposite preparation, properties, and applications
Simulation of Vector Controlled Adjustable Speed System of Doubly Fed Induction Machine
In this work the performance of vector speed control of doubly fed induction machine is considered. Based on the analysis of doubly fed induction machine dynamic mathematical model and the vector control principle, the construction of the motor control system has been completed. Doubly fed induction machine module, the vector controller module, Clark transform module, Park transform module, inverter module, flux module, speed-conditioning module have been set up by0adopting the idea of modular in MATLAB/SIMULINK environment. Through the organic integration of functional modules, the vector control doubly fed induction machine system has been constituted. Simulation results show the changes in the machine electromagnetic torque, the dynamic changes of speed curve, which demonstrate that the real system can be well simulated with fast dynamic response speed, steady-state small of static error, and strong ability of anti-load disturbance
Hydrolysis of proteinaceous tannery solid waste for the production of extracellular acidic protease by Selenomonas ruminantium
The objective of this study was to produce protease from Selenomonas ruminantium using animal fleshing (ANFL), an untanned tannery solid waste as the sole protein source. Optimization of the minimal medium composition for the production of protease was carried out by a statistical approach using response surface methodology (RSM) which includes the variables such as NH4Cl, K2HPO4, KH2PO4 and NaCl. The isolate was found to produce maximum protease at pH 6 and at a temperature of about 40°C. Protease was purified 56 fold with a total yield of 28.14%. The enzyme was found to be monomeric having a molecular weight around 53 kDa. The purified enzyme was stable at a pH of about 4 revealing its acid protease nature and was also found to be stable up to 40°C. The enzyme was activated by divalent cations like Ca2+ and Mg2+ and inhibited by dithiothreitol (DTT), where the latter suggested its cysteine protease nature. The enzyme had good stability in the presence of non-ionic surfactants like tween 20, tween 40, tween 80 and triton X100 and also in the presence of solvents like methanol, ethanol and isopropanol. These characteristics reveal the potential of the enzyme for different industrial applications.Keywords: Acid protease, animal fleshing, optimization, response surface methodology (RSM), Selenomonas ruminantiu
Preliminary phytochemical screening, thin layer chromatography profiling, and in-vitro antiurolithiatic activity of the leaves of Ravenala madagascariensis Sonn.
Urolithiasis, the third most common disorder of the urinary tract is bundled with highly complex and unpredictably varied etiological factors. The undesirable adverse effects with current medications and the recurrence rate pose a major challenge in combating the disorder. Ravenala madagascariensis Sonn. has been used traditionally in treating kidney stone problems. The present study was aimed at investigating the antiurolithiatic activity of different extracts of the leaves of R. madagascariensis. Phytochemical screening carried out on the methanolic, hydromethanolic, and decoction extracts revealed the presence of alkaloids, carbohydrates, glycosides, cardiac glycosides, steroids, proteins, flavonoids, and quinones. Thin layer chromatography profiling of all three extracts was established. The turbidity method was carried out to evaluate in-vitro antiurolithiatic activity and the herbal formulation cystone was used as the standard drug. The results of the study showed that the decoction of R. madagascariensis exhibited excellent antiurolithiatic potential with an IC50 value of 188.65 µg/mL in comparison with the methanolic (305.93 µg/mL) and hydromethanolic (306.83 µg/mL) extracts. Thus the findings of the study validate the claims of antiurolithiatic activity of R. madagascariensis that could be attributed to the presence of active phytoconstituents. Further studies are aimed at its formulation and development
Nickel nanowire: magnetic ordering synthesis
Magnetic nanowires have been material of interest among researchers due to their unique magnetic properties. In the present research, Nickel (Ni) nanowires with an average diameter of 250 nm and length up to 25 μm have been successfully prepared via anodic alumina oxide (AAO) template-assisted electrodeposition method at the different magnetic field intensities and current density. The primary interest is to investigate the effect of the external magnetic field and current density on the morphological, growth length, crystal orientation and growth of the Ni nanowires. Investigation finding reveals that the employed magnetic field and current density smoothened the surface texture, improved growth length and reduced the crystal size. The observed changes are believed to be contributed by the interaction forces induced by the intensity of applied electric field and the external magnetic field known as magnetohydrodynamic (MHD) effect
Preliminary phytochemical screening, thin layer chromatography profiling, and in-vitro antiurolithiatic activity of the leaves of Ravenala madagascariensis Sonn.
425-430Urolithiasis, the third most common disorder of the urinary tract is bundled with highly complex and unpredictably varied etiological factors. The undesirable adverse effects with current medications and the recurrence rate pose a major challenge in combating the disorder. Ravenala madagascariensis Sonn. has been used traditionally in treating kidney stone problems. The present study was aimed at investigating the antiurolithiatic activity of different extracts of the leaves of R.madagascariensis. Phytochemical screening carried out on the methanolic, hydromethanolic, and decoction extractsrevealed the presence of alkaloids, carbohydrates, glycosides, cardiac glycosides, steroids, proteins, flavonoids, andquinones. Thin layer chromatography profiling of all three extracts was established. The turbidity method was carried out toevaluate in-vitro antiurolithiatic activity and the herbal formulation cystone was used as the standard drug. The results of thestudy showed that the decoction of R. madagascariensis exhibited excellent antiurolithiatic potential with an IC50 value of 188.65 μg/mL in comparison with the methanolic (305.93 μg/mL) and hydromethanolic (306.83 μg/mL) extracts. Thus the findings of the study validate the claims of antiurolithiatic activity of R. madagascariensis that could be attributed to the presence of active phytoconstituents. Further studies are aimed at its formulation and development
Seedling selection in open pollinated genotypes of cashew (Anacardium occidentale)
In a highly heterozygous crop like cashew (Anacardium occidentale L.), selection of high yielding trees from a seedling population of existing varieties is one of the ways of development of variety. Hence an experiment was undertaken to study the extent of variability in seedlings of six popular genotypes, viz. NRCC Sel 2, Vengurle 4, Vridhachalam 3, Bhaskara, VTH 174 and VTH 30/4 and to identify promising trees. Eighty open pollinated seeds each from trees belonging to six genotypes were collected; seedlings were raised and planted during 2007 at Directorate of Cashew Research, Experimental Station, Shantigodu. Growth parameters like trunk girth, tree height, tree spread and nut yield per tree were recorded. The progeny performance in different varieties revealed that the mean nut yield per tree was highest with 2.46 kg in Vridhachalam 3. With regard to individual tree performance tree number 480 belonging to VTH 30/4 recorded highest yield of 6.9 kg nuts/tree. The frequency distribution patterns showed that data of trunk girth was moderately negatively skewed implying increasing alleles are in slight excess and dominant for this trait. Whereas tree height and tree spread distributions were moderately positively skewed indicating decreasing alleles are in slight excess and dominant for these traits. The nut yield showed highly positively skewed distribution revealing decreasing alleles are in excess and dominant. The kurtosis was very high for nut yield indicating that yield variability is due to a few extreme differences from the mean. It was observed that trunk girth and tree spread were positively correlated with nut yield. The study could identify one promising seedling (T No.480), a seedling progeny of VTH- 30/4 in terms of nut yield
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