A knowledge-based design environment for spacecraft

A knowledge-based environment for configuration design studies is presented which assists in the conceptual stage design of spacecraft. During this stage, major decisions need to be taken on spacecraft design drivers such as spacecraft mass, power, size, launch vehicle, cost, reliability, etc. This requires a deep understanding of the interacting subsystems of the spacecraft and a thorough examination of the feasible design options and tradeoffs. The environment aids the effective integration of heterogenous data and methods from various disciplines. The dynamic sequencing and control of the design procedure is also highly flexible. The tool has been utilised satisfactorily at the ISRO Satellite Centre for the configuration design of a geosynchronous communications and multipurpose spacecraft

Solid‐Phase Synthesis of Branched Oligonucleotides

Branched nucleic acids (bNAs) have been of particular interest since the discovery of RNA forks and lariats as intermediates of nuclear mRNA splicing, as well as multicopy, single‐stranded DNA (msDNA). Such molecules contain the inherent trait of vicinal 2′,5′‐ and 3′,5′‐phosphodiester linkages. bNAs have many potential applications in nucleic acid biochemistry, particularly as tools for studying the substrate specificity of lariat debranching enzymes, and as biological probes for the investigation of branch recognition during pre‐mRNA splicing. The protocols described herein allow for the facile solid‐phase synthesis of branched DNA and/or RNA oligonucleotides of varying chain length, containing symmetrical or asymmetrical sequences immediate to an RNA branch point. The synthetic methodology utilizes widely adopted phosphoramidite chemistry. Methods for efficient purification of bNAs via anion‐exchange HPLC and PAGE are also illustrated.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143634/1/cpnc0414.pd

Optimization and Biodiesel Production from Prosopis Julifera Oil with High Free Fatty Acids

Prosopis julifera is a non-edible feedstock found in the arid and semi-arid regions was used for the production of biodiesel. Solvent extraction technique was used for oil extraction from Prosopis julifera .The present work mainly concentrates on the three step process of biodiesel production from Prosopis julifera oil .The acid value of Prosopis julifera oil was reduced below 1% using acid catalyst 1% v/v H2SO4 followed by esterification process using alkaline catalyst (KOH).Transesterification reaction is found to be affected by the reaction variables namely methanol to oil molar ratio, amount of catalyst used, reaction time and reaction temperature. Gas chromatography was used to analyse the Fatty acid methyl esters. The methyl ester obtained from the previous step was refined to produce biodiesel. The fuel properties of Prosopis julifera methyl ester (PJME) such as viscosity, cetane number, flash point, acid value, etc were determined and compared according to the ASTM standards. The optimum reaction conditions of Methanol/oil molar ratio of 9:1v/v, reaction temperature of 550C, reaction time of 2 hrs and 0.75% w/v of KOH usage were determined. Response surface Methodology (RSM) technique was used to optimize the maximum yield of Prosopis julifera methyl ester

Fruit/Seed Morphology, Seed Drying and Germination Studies in Baccaurea courtallensis (Muell.) Arg., a Threatened Under-Utilized Fruit Species of Western Ghats in India

A study was under taken on fruit and seed morphology, seed drying, seed germination and storage behavior in Baccaurea courtallensis, as, this plant is propagated mainly through seeds. Its fruit is a berry consisting of an outer, semi-hard but fleshy rind 2-3 mm thick. The cavity inside the rind is normally occupied by a single, arillate seed, but, two seeds are also seen occasionally. Fresh rind was found to be rich in antioxidants, with 237mg total phenols and 93mg flavonoids per 100 gram fresh weight, but was poor in Vitamin C. A thick, fleshy endosperm is surrounded by the inner seed-coat. The endosperm surrounds the embryo consisting of two papery-thin cotyledons and a minute embryonic axis. Germination was highest (96.7%) when seeds were sown immediately after extraction, with moisture content of about 50%. Reduction in moisture to below 34% showed a drastic decrease in germination. Dried seeds took longer to germinate than did the fresh ones. Seeds with 21% moisture recorded about 60% germination whereas, seeds with 10.2% or 8% moisture failed to germinate, indicating a recalcitrant seed. Temperature in the range of 25-30°C was found to be optimum. Of the two media tested for raising the seedlings, cocopeat medium was superior as, it induced faster growth of the seedlings. Seedling root and shoot were considerably longer, with higher seedling survival rate in cocopeat than in the soil-mix medium. Seedling establishment was poor when planted out of their natural habitat

Over-expression of Topoisomerase II Enhances Salt Stress Tolerance in Tobacco

Topoisomerases are unique enzymes having an ability to remove or add DNA supercoils and untangle the snarled DNA. They can cut, shuffle and religate DNA strands and remove the torsional stress during DNA replication, transcription or recombination events. In the present study, we over-expressed topoisomerase II (TopoII) in tobacco (Nicotiana tabaccum) and examined its role in growth and development as well as salt (NaCl) stress tolerance. Several putative transgenic plants were generated and the transgene integration and expression was confirmed by PCR and Southern blot analyses, and RT-PCR analysis respectively. Percent seed germination, shoot growth and chlorophyll content revealed that transgenic lines over-expressing the NtTopoIIα-1 gene exhibited enhanced tolerance to salt (150 and 200 mM NaCl) stress. Moreover, over-expression of TopoII lead to the elevation in proline and glycine betaine levels in response to both concentrations of NaCl as compared to wild-type. In response to NaCl stress, TopoII over-expressing lines showed reduced lipid peroxidation derived malondialdehyde (MDA) generation. These results suggest that TopoII plays a pivotal role in salt stress tolerance in plants

Automated acute ischemic stroke lesion delineation based on apparent diffusion coefficient thresholds

Purpose: Automated lesion segmentation is increasingly used in acute ischemic stroke magnetic resonance imaging (MRI). We explored in detail the performance of apparent diffusion coefficient (ADC) thresholding for delineating baseline diffusion-weighted imaging (DWI) lesions. Methods: Retrospective, exploratory analysis of the prospective observational single-center 1000Plus study from September 2008 to June 2013 (clinicaltrials.org; NCT00715533). We built a fully automated lesion segmentation algorithm using a fixed ADC threshold (≤620 × 10–6 mm2/s) to delineate the baseline DWI lesion and analyzed its performance compared to manual assessments. Diagnostic capabilities of best possible ADC thresholds were investigated using receiver operating characteristic curves. Influential patient factors on ADC thresholding techniques’ performance were studied by conducting multiple linear regression. Results: 108 acute ischemic stroke patients were selected for analysis. The median Dice coefficient for the algorithm was 0.43 (IQR 0.20–0.64). Mean ADC values in the DWI lesion (β = −0.68, p < 0.001) and DWI lesion volumes (β = 0.29, p < 0.001) predicted performance. Optimal individual ADC thresholds differed between subjects with a median of ≤691 × 10−6 mm2/s (IQR ≤660–750 × 10−6 mm2/s). Mean ADC values in the DWI lesion (β = −0.96, p < 0.001) and mean ADC values in the brain parenchyma (β = 0.24, p < 0.001) were associated with the performance of individual thresholds. Conclusion: The performance of ADC thresholds for delineating acute stroke lesions varies substantially between patients. It is influenced by factors such as lesion size as well as lesion and parenchymal ADC values. Considering the inherent noisiness of ADC maps, ADC threshold-based automated delineation of very small lesions is not reliable

Predicting outcome in childhood diffuse midline gliomas using magnetic resonance imaging based texture analysis

BACKGROUND: Diffuse midline gliomas (DMG) are aggressive brain tumours, previously known as diffuse intrinsic pontine gliomas (DIPG), with 10% overall survival (OS) at 18 months. Predicting OS will help refine treatment strategy in this patient group. MRI based texture analysis (MRTA) is novel image analysis technique that provides objective information about spatial arrangement of MRI signal intensity (heterogeneity) and has potential to be imaging biomarker. OBJECTIVES: To investigate MRTA in predicting OS in childhood DMG. METHODS: Retrospective study of patients diagnosed with DMG, based on radiological features, treated at our institution 2007-2017. MRIs were acquired at diagnosis and 6 weeks after radiotherapy (54Gy in 30 fractions). MRTA was performed using commercial available TexRAD research software on T2W sequence and Apparent Diffusion Coefficient (ADC) maps encapsulating tumour in the largest single axial plane. MRTA comprised filtration-histogram technique using statistical and histogram metrics for quantification of texture. Kaplan-Meier survival analysis determined association of MRI texture parameters with OS. RESULTS: 32 children 2-14 years (median 7 years) were included. MRTA was undertaken on T2W (n=32) and ADC (n=22). T2W-MRTA parameters were better at prognosticating than ADC-MRTA. Children with homogenous tumour texture, at medium scale on diagnostic T2W MRI, had worse prognosis (Mean of Positive Pixels (MPP): p=0.005, mean: p=0.009, SD: p=0.011, kurtosis: p=0.037, entropy: p=0.042). Best predictor MPP was able to stratify patients into poor and good prognostic groups with median survival of 7.5 months versus 17.5 months, respectively. CONCLUSIONS: DMG with more homogeneous texture on diagnostic MRI is associated with worse prognosis. Texture parameter MPP is the most predictive marker of OS in childhood DMG