910 research outputs found
ANTIOXIDANT ACTIVITY,TOTAL PHENOL,FLAVONOID,ALKALOID,TANNIN AND SAPONIN CONTENTS OF LEAF EXTRACTS OF SALVINIA MOLESTA D.S.MITCHELL
AbstractObjective:The main aim of the study was to screen leaf extracts of  Salvinia molesta ,a fresh water weed to evaluate the antioxidant activity and also  to quantify total phenol,flavonoid,alkaloid.tannin and saponin contents in order to find possible sources for future novel antioxidants in food and pharmaceutical formulations.Methods:Qualitative and quantitative analyses of significant phytochemicals were performed by standard methods.The antioxidant activity was evaluated using extracts of aqueous, ethanol, methanol, chloroform and petroleum ether by DPPH assay.Butylated Hydroxy Toluene (BHT), Gallic acid (GA) and Quercetin (Q) were taken as standard.Results:Among the five different solvents, maximum antioxidant activity of salvinia molesta was found in ethanolic extract (90.3%) followed by other solvents.Total phenolic content measured by Folin-Ciocalteau method was 9.84 mg Gallic Acid Equivalents (GAE)/g and the total flavonoid contents as measured by aluminium chloride method was 10.89 mg Quercetin Equivalents (QE)/g.Alkaloids,tannins and saponins were measured by standard methods and found in significantly high ranges exhibiting a rich source of phytochemical constituents ensuring the plant as a useful therapeutic agent.Conclusion:Salvinia molesta a fast growing fresh water weed,also abundantly available in nature possess significant antioxidant activity and hence can be used as an potent therapeutic agent. Key words : Salvinia molesta, antioxidant activity, Total phenol ,Flavonoid,Alkaloid,Tannin and Saponin.Â
Design and development of certification compliance tool for airborne systems.
Certification compliance check for airborne software is very critical as it aids in the certification of the software. Since this compliance check is performed manually which is time-consuming and erroneous, an in-house developed Certification Compliance Tool (CCT) helps in checking the compliance as per RTCA DO-178B/C and generate artifacts depicting the magnitude of compliance. In order to generate the magnitude of compliance for the artifacts with respect to the Civil Aerospace Certification standard, RTCA DO-178B/C, an effective parsing technique is required to be incorporated to parse the artifact/s and generate compliance metric for the artifact/s. In this paper we propose a novel approach used in the design and development of an effective and efficient parsing technique incorporated in the indigenous software tool CCT used for compliance check. The tool checks the ratio of compliance of the artifacts generated across various phases of Software Development Life Cycle (SDLC) process involved in the development of Safety-Critical software as per RTCA DO-178B/C. The indigenous tool accepts these artifacts as inputs and based on the software criticality level, it analyzes the compliance of these artifacts with the guidelines provided and recommended by RTCA DO-178B/C. The output of the tool provides the percentage of compliance of the artifacts that helps in accessing the Certification capabilities of the developed software. The percentage of compliance predicts the acceptance or rejection probabilities of the software being certified by the Certification Agency. The certification parser is developed using Python modules like Pywin32, Pypdf parsers and different approaches for Natural language processing using Python Natural Language Toolkit (NLTK). The in-house tool replaces the manual effort by an individual/s which may be erroneous and impact the time-schedule, which compromises the software safety. The integration of the tool with commercial tools will help in analyzing the report/ documentation content with respect to the certification
Architecture Level Safety Analyses for Safety-Critical Systems
The dependency of complex embedded Safety-Critical Systems across Avionics and Aerospace domains on their underlying software and hardware components has gradually increased with progression in time. Such application domain systems are developed based on a complex integrated architecture, which is modular in nature. Engineering practices assured with system safety standards to manage the failure, faulty, and unsafe operational conditions are very much necessary. System safety analyses involve the analysis of complex software architecture of the system, a major aspect in leading to fatal consequences in the behaviour of Safety-Critical Systems, and provide high reliability and dependability factors during their development. In this paper, we propose an architecture fault modeling and the safety analyses approach that will aid in identifying and eliminating the design flaws. The formal foundations of SAE Architecture Analysis & Design Language (AADL) augmented with the Error Model Annex (EMV) are discussed. The fault propagation, failure behaviour, and the composite behaviour of the design flaws/failures are considered for architecture safety analysis. The illustration of the proposed approach is validated by implementing the Speed Control Unit of Power-Boat Autopilot (PBA) system. The Error Model Annex (EMV) is guided with the pattern of consideration and inclusion of probable failure scenarios and propagation of fault conditions in the Speed Control Unit of Power-Boat Autopilot (PBA). This helps in validating the system architecture with the detection of the error event in the model and its impact in the operational environment. This also provides an insight of the certification impact that these exceptional conditions pose at various criticality levels and design assurance levels and its implications in verifying and validating the designs
A Study to assess the effectiveness of yellow myrobalan (Kadukkai) powder dressing on wound healing in clients with Diabetic Foot Ulcer in selected wards at Rajiv Gandhi Government General Hospital, Chennai.
Diabetes is the global epidemic problem with devastating human, social and economic consequences. Diabetic foot ulcer is the most serious and costly complications and important cause of morbidity in diabetic people over the years. Need for the study: The recent statistical data shows that diabetic foot ulcers are suggest that around 10% of people with diabetes develop foot ulcers. Foot ulceration is the precursor to approximately85%of all diabetic amputations and it is estimated that14%- 20%of clients with foot ulcers will have to undergo amputation infection. So different treatment modalities needed to care and minimize the complications of diabetic foot ulcer, thus provoked the researcher to do this study
A tandem duplication within the fibrillin 1 gene is associated with the mouse tight skin mutation.
Mice carrying the Tight skin (Tsk) mutation have thickened skin and visceral fibrosis resulting from an accumulation of extracellular matrix molecules. These and other connective tissue abnormalities have made Tskl + mice models for scleroderma, hereditary emphysema, and myocardial hypertrophy. Previously we localized Tsk to mouse chromosome 2 in a region syntenic with human chromosome 15. The microfibrillar glycoprotein gene, fibrillin 1 (FBN1), on human chromosome 15q, provided a candidate for the Tsk mutation. We now demonstrate that the Tsk chromosome harbors a 30- to 40-kb genomic duplication within the Fbn1 gene that results in a larger than normal in-frame Fbn1 transcript. These findings provide hypotheses to explain some of the phenotypic characteristics of Tskl + mice and the lethality of Tsk/Tsk embryos
Using System Analysis Modeling Language (SAML) for validating the critical aerospace model.
System Analysis Modeling Language (SAML) is a formal language which helps in expressing and analyzing the qualitative and quantitative aspects of the software as well as hardware models. This can be used in model-based safety analysis (MBSA) which provides the means of identifying, localizing and analyzing hazards in these real-time Safety-Critical Systems. This paper describes the work carried out in the organization to validate the complex and critical Mode-Transition Logic (MTL) in Automated Flight Control System (AFCS) being developed in the organization. The Mode-Transition Logic (MTL) of the AFCS system is re-modeled using SAML and further analyzed with model checkers such as PRISM and NuSMV, for generation of counter-examples. The counter examples helped in mapping the safety scenarios along the AFCS requirements. These counter examples also helped in generating the fault model and analyzing the system logic for fault tolerance. Using NUSMV, MTL the failure scenarios were generated and the allowed transitions were studied. Failure management analysis report is generated and mapped as an artefact for the certification. For the illustration of the proposed approach, a suitable framework viz. Verification Environment for Safety-Critical Systems (VECS) is used to validate the utility of Mode-Transition Logic (MTL) in Automated Flight Control System (AFCS). The critical operations and complex functions were analyzed for contingency situations and provide means in significantly enhancing the safe operation of the Safety-Critical System. The mapping of the model safety using this approach will provide compliance with Civil Aerospace Standard DO-178C and DO-331 using Model-Based Design
Factors Responsible for the Stability and the Existence of a Clean Energy Gap of a Silicon Nanocluster
We present a critical theoretical study of electronic properties of silicon
nanoclusters, in particular the roles played by symmetry, relaxation, and
hydrogen passivation on the the stability, the gap states and the energy gap of
the system using the order-N [O(N)] non-orthogonal tight-binding molecular
dynamics and the local analysis of electronic structure.Comment: 26 pages including figure
Bioefficacy of certain chemical and biofungicides against Hypoxylon spp. causing wood rot disease in tea
Wood rot disease caused by Hypoxylon serpens is the most widespread and serious stem disease in tea. Among the 350 bacterial and 35 fungal biocontrol isolates collected from several tea growing regions of southern India, three bacterial isolates produced higher antagonistic potential against this fungal pathogen. Two of the efficient strains were identified as Bacillus sp. (HBCWR-3 and WR46-2) and third one was Pseudomonas sp. (WR5-4). In case of fungal biocontrol agents, the type culture Trichoderma viride procured from Microbial Type Culture Collection (MTCC) performed better in controlling the pathogen over T. harzianum. Five systemic fungicides, hexaconazole, carbendazim, tebuconazole, tridemorph, benomyl and a contact fungicide, copper oxychloride were evaluated for studying their bioefficacy against wood rot pathogen. In this study, benomyl 50% WP or copper oxychloride at the lowest concentration (0.01%) completely inhibited the growth of the fungus in vitro. Moreover, bioefficacy of certain plant aqueous extracts of Azadirachta indica, acetone extracts of Pongamia pinnata, Cinnamom, Artemisia nilagirica, Lantana camera, Ageratum conyzoides and a bryophyte, Heteroscyphus argutus were also studied against H. serpens. Among them, A. nilagirica followed by H. argutus and A. indica were effective in controlling the wood rot pathogen. In the case of liquid biofungicides tested, ‘Expel’ controlled the tea pathogen efficiently. The present study revealed that, chemical fungicide (Benomyl or copper oxychloride at 0.01%), botanical extracts at 10% (A. nilagirica, H. argutus, Azadirachta and ‘Expel’) and biocontrol agents (Bacillus sp., Pseudomonas sp. and T. viride) were effective in controlling wood rot pathogen under in vitro condition
A Modeling and Verification Study of Summer Precipitation Systems Using NASA Surface Initialization Datasets
One of the most challenging weather forecast problems in the southeastern U.S. is daily summertime pulse-type convection. During the summer, atmospheric flow and forcing are generally weak in this region; thus, convection typically initiates in response to local forcing along sea/lake breezes, and other discontinuities often related to horizontal gradients in surface heating rates. Numerical simulations of pulse convection usually have low skill, even in local predictions at high resolution, due to the inherent chaotic nature of these precipitation systems. Forecast errors can arise from assumptions within parameterization schemes, model resolution limitations, and uncertainties in both the initial state of the atmosphere and land surface variables such as soil moisture and temperature. For this study, it is hypothesized that high-resolution, consistent representations of surface properties such as soil moisture, soil temperature, and sea surface temperature (SST) are necessary to better simulate the interactions between the surface and atmosphere, and ultimately improve predictions of summertime pulse convection. This paper describes a sensitivity experiment using the Weather Research and Forecasting (WRF) model. Interpolated land and ocean surface fields from a large-scale model are replaced with high-resolution datasets provided by unique NASA assets in an experimental simulation: the Land Information System (LIS) and Moderate Resolution Imaging Spectroradiometer (MODIS) SSTs. The LIS is run in an offline mode for several years at the same grid resolution as the WRF model to provide compatible land surface initial conditions in an equilibrium state. The MODIS SSTs provide detailed analyses of SSTs over the oceans and large lakes compared to current operational products. The WRF model runs initialized with the LIS+MODIS datasets result in a reduction in the overprediction of rainfall areas; however, the skill is almost equally as low in both experiments using traditional verification methodologies. Output from object-based verification within NCAR s Meteorological Evaluation Tools reveals that the WRF runs initialized with LIS+MODIS data consistently generated precipitation objects that better matched observed precipitation objects, especially at higher precipitation intensities. The LIS+MODIS runs produced on average a 4% increase in matched precipitation areas and a simultaneous 4% decrease in unmatched areas during three months of daily simulations
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