10 research outputs found

    Bioactive Molecules from Indian Medicinal Plants as Possible Candidates for the Management of Neurodegenerative Disorders

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    The present review gives an account of various bioactive molecules obtained from Indian medicinal plants for neurological degenerative disorders. Emphasis is laid on their correlation with the plants used in traditional system of medicine in India. The methodology involved in present review was enlisting of medicinal plants used for neurodegenerative disorders followed by their chemistry. A correlation with the chemical constituents and their recent findings has been done. Many medicinal plants such as Aloe vera and Bacopa monnieri have documented correlations and also need to be explored more. Molecules like garcinol (34), which was originally an anticancer compound, have good correlation as neuroprotective agent. Likewise many plants that have not been explored but are used in traditional system of medicine have also been listed. Jaggery and honey, which are used in traditional formulations in large quantity, also have natural products that are used as neuroprotective agents. In conclusion, a lot more study is required to correlate the medicinal plants and herbal formulations to have much more natural products for neurodegenerative disorders

    Comparative Study of the Oxidation Products of Dimethylglyoxime in Conventional and Microwave Heating Conditions

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    Abstract: Microwave has proved to be a convenient tool in the hands of chemists for organic synthetic processes in the recent past. In the present work, the products obtained by the oxidation of dimethylglyoxime (DmgH 2 ) in tetrahydrofuran (THF) by ditertiary butyl chromate (TBC) in conventional and microwave dielectric heating conditions are studied. The analysis of the compounds was done by chemical as well as instrumental methods including FTIR and DTA/TGA mass loss pattern. The results clearly indicate that the reactions are much efficient, less energy and time consuming in case of microwave dielectric heating as compared to those in conventional methods

    Flux Enhancement By Shear Free Surfaces In A Turbulent Convection

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    Abstract: In this Paper we will be dealing with turbulent natural convection in a long vertical pipe in which the flow is generated because of an unstable density difference across the two ends of the pipe. We create the density difference across the pipe using fresh water and brine. Since the density of brine is greater than that of fresh water, it tries to settle down while the fresh water tries to fill up the upper space. This creates collision of fluid masses in the pipe, leading to a turbulent flow at high levels of density differences. We will study the flow and its effect in the mid section of the pipe. Since water is an incompressible fluid, because of the density difference, the mass of fluid that goes up is equal to the mass of the fluid going down. Thus at any instant of time, the net flow will be zero at any cross section of the pipe. Since the length to diameter ratio (L/d ratio) of the pipe is around 9 to 10, the flow will be axially homogeneous. Thus we have an axially homogenous flow with zero mean velocity and which is purely buoyancy driven. This is the basic flow for our experiments

    Effect of Ligands and Solvents on the Stability of Electron Charged CdSe Colloidal Quantum Dots

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    Many colloidal quantum dot (QD)-based devices involve charging of the QD, either via intentional electronic doping or via electrical charge injection or photoexcitation. Previous research has shown that this charging can give rise to undesirable electrochemical surface reactions, leading to the formation of localized in-gap states. However, little is known about the factors that influence the stability of charged QDs against surface oxidation or reduction. Here, we use density functional theory to investigate the effect of various ligands and solvents on the reduction of surface Cd in negatively charged CdSe QDs. We find that X-type ligands can lead to significant shifts in the energy of the band edges but that the in-gap state related to reduced surface Cd is shifted in the same direction. As a result, shifting the band edges to higher energies does not necessarily lead to less stable electron charging. However, subtle changes in the local electrostatic environment lead to a clear correlation between the position of the in-gap state in the bandgap and the energy gained upon surface reduction. Binding ligands directly to the Cd sites most prone to reduction was found to greatly enhance the stability of the electron charged QDs. We find that ligands bind much more weakly after reduction of the Cd site, leading to a loss in binding energy that makes charge localization no longer energetically favorable. Lastly, we show that increasing the polarity of the solvent also increases the stability of QDs charged with electrons. These results highlight the complexity of surface reduction reactions in QDs and provide valuable strategies for improving the stability of charged QDs. ChemE/Opto-electronic Material

    Anther Culture Efficiency in Quality Hybrid Rice: A Comparison between Hybrid Rice and Its Ratooned Plants

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    An immense increase in human population along with diminished lands necessitates the increase of rice production since, it serves the human population as a staple food. Though rice hybrids (RH) are showing considerable yield enhancement over inbreds in terms of both quality and quantity, farmers’ adoption of hybrid rice technology has been much slower than expected because of several constraints such as seed cost and quality. Doubled haploid (DH) technology was considered useful for the development of inbred lines from rice hybrids in a single generation. Androgenesis shows its significance in development of DHs in rice which requires an efficient method to establish the production of large population. To start the anther culture, anthers are the main component of androgenesis to be isolated from unopened spikes. However, the duration of spikes availability for anther culture coupled with the segregation of rice hybrids in the next generation requires the main crop be ratooned to reduce the cost of cultivation. Therefore, the efficiency of the androgenic method was tested in main crop using a quality indica rice hybrid, 27P63 and its ratooned ones. The effects of various factors such as cold temperature pre-treatment of boots, treatment duration, and different combination of plant growth regulators (PGR) on callus response along with shoot regeneration were tested for development of DHs from both ratooned and non-ratooned plants. The N6 medium supplemented with 2.0 mg/L 2,4-D (2,4-dichlrophenoxy acetic acid), 0.5 mg/L BAP (6-benzylamino purine), and 30 g/L maltose was found to be most effective for callusing as compared to MS (Murashige and Skoog) medium. The N6 media inducted calli showed maximum response rate for green shoot regeneration in MS media supplemented with 0.5 mg/L NAA (1-napthaleneacetic acid), 0.5 mg/L Kn (Kinetin; 6-furfurylaminopurine), 1.5 mg/L BAP and 30 g/L sucrose after 2 weeks of culture. The pre-treatment of spikes at 10 °C for 2 d followed by a 7th and 8th d were found to be most effective for callusing as well as for regeneration, producing a total of 343 green plants from ratooned and main rice hybrid, 27P63. Morpho-agronomic trait-based assessment of ploidy status revealed 94.46% diploids, 3.49% polyploids, 0.58% mixploids, and 1.45% haploids. Microsatellite markers could authenticate all 324 fertile diploids as true DHs. Though this study shows a reduction in generation of DHs from ratooned plants as compared to the main crop, manipulation of chemical factors could optimize the method to enhance the production of considerable number of DHs. Utilization of ratooned of hybrid rice in androgenesis would save time and cost of cultivation

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    Not AvailableAn immense increase in human population along with diminished lands necessitates the increase of rice production since, it serves the human population as a staple food. Though rice hybrids (RH) are showing considerable yield enhancement over inbreds in terms of both quality and quantity, farmers’ adoption of hybrid rice technology has been much slower than expected because of several constraints such as seed cost and quality. Doubled haploid (DH) technology was considered useful for the development of inbred lines from rice hybrids in a single generation. Androgenesis shows its significance in development of DHs in rice which requires an efficient method to establish the production of large population. To start the anther culture, anthers are the main component of androgenesis to be isolated from unopened spikes. However, the duration of spikes availability for anther culture coupled with the segregation of rice hybrids in the next generation requires the main crop be ratooned to reduce the cost of cultivation. Therefore, the efficiency of the androgenic method was tested in main crop using a quality indica rice hybrid, 27P63 and its ratooned ones. The effects of various factors such as cold temperature pre-treatment of boots, treatment duration, and different combination of plant growth regulators (PGR) on callus response along with shoot regeneration were tested for development of DHs from both ratooned and non-ratooned plants. The N6 medium supplemented with 2.0 mg/L 2,4-D (2,4-dichlrophenoxy acetic acid), 0.5 mg/L BAP (6-benzylamino purine), and 30 g/L maltose was found to be most effective for callusing as compared to MS (Murashige and Skoog) medium. The N6 media inducted calli showed maximum response rate for green shoot regeneration in MS media supplemented with 0.5 mg/L NAA (1-napthaleneacetic acid), 0.5 mg/L Kn (Kinetin; 6-furfurylaminopurine), 1.5 mg/L BAP and 30 g/L sucrose after 2 weeks of culture. The pre-treatment of spikes at 10 ◦C for 2 d followed by a 7th and 8th d were found to be most effective for callusing as well as for regeneration, producing a total of 343 green plants from ratooned and main rice hybrid, 27P63. Morpho-agronomic trait-based assessment of ploidy status revealed 94.46% diploids, 3.49% polyploids, 0.58% mixploids, and 1.45% haploids. Microsatellite markers could authenticate all 324 fertile diploids as true DHs. Though this study shows a reduction in generation of DHs from ratooned plants as compared to the main crop, manipulation of chemical factors could optimize the method to enhance the production of considerable number of DHs. Utilization of ratooned of hybrid rice in androgenesis would save time and cost of cultivation.ICAR-NRRI, Cuttac

    Bandlike transport and charge-carrier dynamics in BiOI films

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    Following the emergence of lead halide perovskites (LHPs) as materials for efficient solar cells, research has progressed to explore stable, abundant, and nontoxic alternatives. However, the performance of such lead-free perovskite-inspired materials (PIMs) still lags significantly behind that of their LHP counterparts. For bismuth-based PIMs, one significant reason is a frequently observed ultrafast charge-carrier localization (or self-trapping), which imposes a fundamental limit on long-range mobility. Here we report the terahertz (THz) photoconductivity dynamics in thin films of BiOI and demonstrate a lack of such self-trapping, with good charge-carrier mobility, reaching ∼3 cm 2 V -1 s -1 at 295 K and increasing gradually to ∼13 cm 2 V -1 s -1 at 5 K, indicative of prevailing bandlike transport. Using a combination of transient photoluminescence and THz- and microwave-conductivity spectroscopy, we further investigate charge-carrier recombination processes, revealing charge-specific trapping of electrons at defects in BiOI over nanoseconds and low bimolecular band-to-band recombination. Subject to the development of passivation protocols, BiOI thus emerges as a superior light-harvesting semiconductor among the family of bismuth-based semiconductors. </p

    Bandlike Transport and Charge-Carrier Dynamics in BiOI Films

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    Following the emergence of lead halide perovskites (LHPs) as materials for efficient solar cells, research has progressed to explore stable, abundant, and nontoxic alternatives. However, the performance of such lead-free perovskite-inspired materials (PIMs) still lags significantly behind that of their LHP counterparts. For bismuth-based PIMs, one significant reason is a frequently observed ultrafast charge-carrier localization (or self-trapping), which imposes a fundamental limit on long-range mobility. Here we report the terahertz (THz) photoconductivity dynamics in thin films of BiOI and demonstrate a lack of such self-trapping, with good charge-carrier mobility, reaching ∼3 cm2 V–1 s–1 at 295 K and increasing gradually to ∼13 cm2 V–1 s–1 at 5 K, indicative of prevailing bandlike transport. Using a combination of transient photoluminescence and THz- and microwave-conductivity spectroscopy, we further investigate charge-carrier recombination processes, revealing charge-specific trapping of electrons at defects in BiOI over nanoseconds and low bimolecular band-to-band recombination. Subject to the development of passivation protocols, BiOI thus emerges as a superior light-harvesting semiconductor among the family of bismuth-based semiconductors
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