2,970 research outputs found
Mixed-surfactant system of dodecylbenzene sulfonate and alpha-olefin sulfonate: micellar and volumetric studies
Critical micelle concentrations of sodium salts of dodecylbenzene sulfonate, α-olefin (C16) sulfonate, and their mixtures have been evaluated by measuring the surface tensions of solutions at 298.15 K. Interaction parameters for mixed monolayer formation (βσ) and mixed-micelle formation (βM) have been calculated from the critical micelle concentration data. Densities of solutions of surfactants and their mixtures were measured with a vibrating-tube densimeter at 298.15 K. Apparent and partial molar volumes have been evaluated from solution density data. Results of the micellar properties have been eplained on the basis of a nonideal multicomponent mixed-micelle model. The mixed-surfactant system exhibits synergism in all aspects when the mole fraction of alpha-olefin sulfonate in the mixture is 0.2. Volumetric properties correlate well, as the partial molar volumes also show a minimum at the same composition of the mixture. Formation of a compact mixed micelle at this composition has been envisaged
Modelling and analysis of a modified Dodecapod parallel manipulator
Parallel manipulator is one of the areas of research extensively studied by many researchers from past 4-5 decades. Unlike their serial counterparts, parallel manipulators exhibit higher rigidity and controllability when operating at higher speeds. These attributes lead to their application in various fields such as machine tools, simulators and positioning systems. Present work is proposing a modified reconfigurable Dodecapod parallel manipulator. 3D model of the proposed manipulator is successfully developed and kinematics analysis is carried out. Re-configurable sliders are provided to vary the workspace as required. A few illustrative examples are demonstrated for various locations of slider, showing changes in workspace. The novelty of the present manipulator overcomes the workspace limitations of the general Stewart Gough manipulator. Present modified Dodecapod parallel manipulator is capable of improving local kinematic performance
Qualitative and Quantitative Analysis of Native Food Products for Probiotic Properties
Certain properties relevant to probiotic action, e.g. resistance to acid, bile tolerance, antibacterial activity, and antibiotic susceptibility were investigated of lactobacilli isolated from three kinds of Indian traditional fermented foods. Media of pH = 2.0–7.0 and bile salt concentrations of 0.3–1.0% were used as stress conditions. Antibacterial activity of the probiotic lactobacilli was determined by means of the Well diffusion test. The results revealed that the antibacterial activity of the three selected lactobacilli could inhibit all test pathogenic bacteria however at different inhibition levels. Among 7 isolates, only 3 strains (two from paneer and one from Ragi porridge) showed extremely high survival rates under stress caused by acid or bile salts. The three strains inhibited test pathogenic bacteria to different extents. They were sensitive to chloramphenicol, quinupristin, Chloramphenicol, Tetracyclin, Rifampicin and Streptomycin but resistant to Gentamicin, Vancomycin, Ciproflaxin and Penicillin
Light Scattering on Nanowire Antennas: A Semi-Analytical Approach
Two semi-analytical approaches to solve the problem of light scattering on
nanowire antennas are developed and compared. The derivation is based on the
exact solution of the plane wave scattering problem in case of an infinite
cylinder. The original three-dimensional problem is reduced in two alternative
ways to a simple one-dimensional integral equation, which can be solved
numerically by a method of moments approach. Scattering cross sections of gold
nanowire antennas with different lengths and aspect ratios are analysed for the
optical and near-infrared spectral range. Comparison of the proposed
semi-analytical methods with the numerically rigorous discrete dipole
approximation method demonstrates good agreement as well as superior numerical
performance.Comment: 9 pages, 5 figure
Translational genomics and molecular breeding for enhancing precision and efficiency in crop improvement programs: Some examples in legumes
Legumes like chickpea, pigeonpea and groundnut are protein rich, nutrient-dense, and nitrogen fixing crops. Their importance is increasingly recognized in view of the urgent need to address burgeoning malnutrition problem and to impart sustainability to cropping systems. Breeding programs in these crops have achieved great success. However, consistent improvement in genetic gains demands integration of innovative tools and technologies with crop breeding programs. Genomic resources are of paramount significance in context of improving the efficiency and precision of crop breeding schemes. The last decade has witnessed a remarkable success in generating unprecedented genomic resources in these crops, thus transforming these genomic orphans into genomic resource rich crops. These genomic resources include array-based genotyping platforms, high-resolution genetic linkage maps/HapMaps, comprehensive transcriptome assemblies and gene expression atlas, and whole genome sequences etc. Further progression from the training phase (development) to breeding (deployment) phase is marked with the current availability of a variety of molecular breeding products in these legume crops. In the present review, we discuss how deployment of the modern genomic resources such as next-generation gene discovery techniques and “gold standard experimental designs” is furthering our knowledge about the genetic underpinnings of trait variation. Also, key success stories demonstrating the power of molecular breeding in these legume crops are highlighted. It is opined that the breeding populations constantly improved by sequence-based breeding approach will greatly help improving breeding traits and the genetic gains accruable from crop breeding programs
HI Fluctuations at Large Redshifts: I--Visibility correlation
We investigate the possibility of probing the large scale structure in the
universe at large redshifts by studying fluctuations in the redshifted 1420 MHz
emission from the neutral hydrogen (HI) at early epochs. The neutral hydrogen
content of the universe is known from absorption studies for z<4.5. The HI
distribution is expected to be inhomogeneous in the gravitational instability
picture and this inhomogeneity leads to anisotropy in the redshifted HI
emission. The best hope of detecting this anisotropy is by using a large
low-frequency interferometric instrument like the Giant Meter-Wave Radio
Telescope (GMRT). We calculate the visibility correlation function <V_nu(u)
V_nu'(u)> at two frequencies nu and nu' of the redshifted HI emission for an
interferometric observation. In particular we give numerical results for the
two GMRT channels centered around nu =325 and 610 MHz from density
inhomogeneity and peculiar velocity of the HI distribution. The visibility
correlation is ~10^-9 to 10^-10 Jy^2. We calculate the signal-to-noise for
detecting the correlation signal in the presence of system noise and show that
the GMRT might detect the signal for integration times ~ 100 hrs. We argue that
the measurement of visibility correlation allows optimal use of the
uncorrelated nature of the system noise across baselines and frequency
channels.Comment: 17 pages, 2 figures, Submitted to JA
Treatment with Y-27632, a ROCK Inhibitor, Increases the Proinvasive Nature of SW620 Cells on 3D Collagen Type 1 Matrix
The concept of using tissue density as a mechanism to diagnose a tumor has been around for centuries. However, this concept has not been sufficiently explored in a laboratory setting. Therefore, in this paper, we observed the effects of cell density and extracellular matrix (ECM) density on colon cancer invasion and proliferation using SW620 cells. We also attempted to inhibit ROCK-I to determine its effect on cell invasion and proliferation using standard molecular biology techniques and advanced imaging. Increasing cell seeding density resulted in a 2-fold increase in cell invasion as well as cell proliferation independent of treatment with Y-27632. Increasing collagen I scaffold density resulted in a 2.5-fold increase in cell proliferation while treatment with Y-27632 attenuated this effect although 1.5 fold increase in cell invasion was observed in ROCK inhibited samples. Intriguingly, ROCK inhibition also resulted in a 3.5-fold increase in cell invasion within 3D collagen scaffolds for cells seeded at lower densities. We show in this paper that ROCK-I inhibition leads to increased invasion within 3D collagen I microenvironments. This data suggests that although ROCK inhibitors have been used clinically to treat several medical conditions, its effect largely depends on the surrounding microenvironment
Inheritance of parthenocarpy in gynoecious cucumber (Cucumis sativus L.) cultivar PPC-2
The gynoecious and parthenocarpic inbred line, Pant Parthenocarpic Cucumber-2 (PPC- 2) was crossed with Indian monoecious and non-parthenocarpic cultivar Pusa Uday to develop F1, F2, B1 and B2 to determine the inheritance of parthenocarpy.The crop was grown under insect proof net house of 40 mesh. The pistillate buds were covered using butter paper bags before anthesis to prevent out-crossing.The observations were recorded separately for the development of early parthenocarpic fruits (i.e.1-7th nodes), late parthenocarpy (8th and above nodes) and non-parthenocarpic fruits. In F1 generation, out of 40 plants screened, 2 plants produced parthenocarpic fruits at lower nodes (1-7th nodes), 37 plants produced parthenocarpic fruits at upper nodes (8th and above), whereas,only 1 plant that did not produced any fruit was considered as non-parthenocarpic. The segregation of F2 population and test crosses for parthenocarpic fruit development suggested that parthenocarpy in gynoecious and parthenocarpic cucumber line PPC-2 is under the control of incomplete dominant gene
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