363 research outputs found

    Registration of Airborne Infrared Images using Platform Attitude Information

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    In current warfare scenario stealth and passive threat detection capabilities are considered as prime requirements to accomplish desired mission by the fighter aircrafts. To improve the stealth of an aircraft, the trend is towards detecting threats with the help of passive sensors (Electro Optic or Infrared). Current situation caters for systems like Infra-red Search and Track (IRST) and Passive Missile Warning Systems (PMWS). IRST system is a passive target detection system, used for detecting aerial & ground targets. PMWS is a threat detection system used for detecting missiles approaching towards aircraft. Both of these systems detect targets of interest by processing IR images acquired in mid-IR region. The prime challenge in IRST system or PMWS is detecting a moving target of size typically 1~2 pixels in acquired image sequences. The temporal change caused by moving target in consecutive frames can be considered as one important factor to detect them. The temporal change caused by moving target is identified through absolute frame differencing of successive frames. This principle has limitation in application to IRST & PMWS as the imaging sensor with the aircraft is moving. This motion also imparts temporal change in the acquired images. In this paper authors are proposing a method for removing the temporal change caused by the platform motion in two consequently acquired frames using registration process.  The proposed method uses the platform attitude information at frame sampling times. Authors have analyzed the sensitivity of registration process to noisy platform attitude information.Defence Science Journal, 2014, 64(2), pp. 130-135. DOI: http://dx.doi.org/10.14429/dsj.64.546

    Origin of charge density wave formation in insulators from a high resolution photoemission study of BaIrO3

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    We investigate the origin of charge density wave (CDW) formation in insulators by studying BaIrO3 using high resolution (1.4 meV) photoemission spectroscopy. The spectra reveal the existence of localized density of states at the Fermi level in the vicinity of room temperature. These localized states are found to vanish as the temperature is lowered thereby, opening a soft gap at the Fermi level, as a consequence of CDW transition. In addition, the energy dependence of the spectral density of states reveals the importance of magnetic interactions, rather than well-known Coulomb repulsion effect, in determining the electronic structure thereby implying a close relationship between ferromagnetism and CDW observed in this compound. Also, Ba core level spectra surprisingly exhibit an unusual behavior prior to CDW transition.Comment: 4 pages, 4 figures. To appear in Physical Review Letter

    Analgorithmic Framework for Automatic Detection and Tracking Moving Point Targets in IR Image Sequences

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    Imaging sensors operating in infrared (IR) region of electromagnetic spectrum are gaining importance in airborne automatic target recognition (ATR) applications due to their passive nature of operation. IR imaging sensors exploit the unintended IR radiation emitted by the targets of interest for detection. The ATR systems based on the passive IR imaging sensors employ a set of signal processing algorithms for processing the image information in real-time. The real-time execution of signal processing algorithms provides the sufficient reaction time to the platform carrying ATR system to react upon the target of interest. These set of algorithms include detection, tracking, and classification of low-contrast, small sized-targets. Paper explained a signal processing framework developed to detect and track moving point targets from the acquired IR image sequences in real-time.Defence Science Journal, Vol. 65, No. 3, May 2015, pp.208-213, DOI: http://dx.doi.org/10.14429/dsj.65.816

    Radioiodine Therapy for Hyperthyroidism Changing Pattern of Management over Three Decades at INMAS

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    Iodine - 131 therapy is a relatively simple, effective and economical method of treating hyperthyroidism. Even fifty years after the introduction of radioactive iodine, there is no concensus on the approach for selection of the dose for treatment of hyperthyroidism. Since the last three decades, the approach for radioiodine therapy at this Institute has been to treat with low, fractionated doses to produce partial destruction of the thyroid gland leaving the patient sufficient functioning gland for normal hormone production. New in vitro diagnostic techniques including free T/sub 3/, T/sub 4/ and sensitive TSH assay have been introduced over the past decade for the diagnosis of hyperthyroidism. Changes in the thyroid radioactive iodine uptake in the population due to introduction of iodized salt, and the high incidence of persistent hyperthyroidism after low dose radioiodine therapy, have prompted to go for a proporptionate increase in the /sup 131/I original dose schedules based on goitre grades. This has led to nominal increase in the incidence of post therapy hypothyroidism. However, the basic principle of low, fractionated dose therapy is still being followed at this Institute, which appears suitable for our social and economic condition

    Revelation of the role of impurities and conduction electron density in the high resolution photoemission study of ferromagnetic hexaborides

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    We investigate the temperature evolution of the electronic structure of ferromagnetic CaB6 using ultrahigh resolution photoemission spectroscopy; the electronic structure of paramagnetic LaB6 is used as a reference. High resolution spectra of CaB6 reveal a finite density of states at the Fermi level εF at all the temperatures and evidence of impurity induced localized features in the vicinity of εF, which are absent in the spectra of LaB6. Analysis of the high resolution spectra suggests that disorder in the B sublattice inducing partial localization in the mobile electrons and low electron density at εF is important to achieve ferromagnetism in these systems

    Early Clinical Detection of Pharmacologic Response in Insulin Action in a Nondiabetic Insulin-Resistant Population

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    AbstractBackgroundInsulin resistance heightens the risk for type 2 diabetes mellitus and cardiovascular disease. Amelioration of insulin resistance may reduce this risk. The thiazolidinedone class of insulin sensitizers improves insulin action in individuals with insulin-resistant diabetes and nondiabetic individuals. However, there are few reports on the time of onset of such effects independent of reversal of glucotoxicity.ObjectiveThe goal of our study was to test whether the thiazolidinedione pioglitazone has prominent early metabolic effects that can be detected in an obese, nondiabetic, insulin-resistant population.MethodsWe conducted a randomized, double-blind, placebo-controlled, parallel-group trial in men with nondiabetic insulin resistance using a hyperinsulinemic euglycemic clamp technique (at low and high doses of insulin at 10 and 40 mU/m2/min, respectively). The patients were given 30 mg daily oral pioglitazone or placebo for 28 days. Patients underwent a baseline clamp before initiation of treatment, and again at 14 and 28 days of treatment.ResultsCompared with placebo, under high-dose hyperinsulinemia, pioglitazone led to significant increases in glucose disposal rates (GDR) of 1.29 mg/kg/min (90% CI, 0.43–2.15; 39%; P=0.008) that were detectable at 2 weeks of treatment and persisted at 4 weeks of treatment. Under low-dose hyperinsulinemia, significant increases in GDR of 0.40 mg/kg/min (90% CI, 0.17–0.62; 95%; P=0.003) were observed at 4 weeks of treatment. These responses were accompanied by robust suppression of free fatty acids under hyperinsulinemic conditions, and by significant increases in circulating basal total adiponectin at 2 and 4 weeks of treatment.ConclusionsSignificant changes in insulin action across multiple insulin-sensitive tissues can be detected within 2 weeks of initiation of insulin-sensitizing therapy with pioglitazone in obese patients with nondiabetic insulin resistance. ClinicalTrials.gov identifier: NCT01115712

    EVALUATION OF GENOTOXICITY PROFILE OF JASADA BHASMA (A ZINC-BASED MINERAL FORMULATION) IN SWISS ALBINO MICE

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      Objective: Genotoxicity is regarded as one of the potential risk factors for causing pathological diseases. It was confirmed that many chemicals have the mutagenic activity which leads to cancer. A compound which interacts with genetic material DNA and shows adverse effects by altering its structure or function is referred to as genotoxic.Methods: The present study involved 40 Swiss albino mice weighing between 25 and 30 g body weights categorized into four different groups. Group-I (normal control) received 0.5% carboxymethyl cellulose as vehicle. Group-II (toxicant control) received 40 mg/kg/body weight cyclophosphamide on the 28th day. Group-III and IV received test drug JB 15.6 mg/kg and 78 mg/kg, respectively, for 28 consecutive days. Blood samples were collected and processed for evaluating by comet assay. The animals were sacrificed and collected the bone marrow from both the femur for chromosomal aberration and micronuclei assay.Results: JB administered at two different dose levels did not show any significant changes in the comet assay parameters, no micronucleus was found and did not produce any chromosomal aberrations both numerically and structurally when compared to positive test control group.Conclusion: The genotoxicity evaluation of JB did not show any chromosomal aberrations and presence of micronucleus. Thus, the safety data will refine therapeutic utility of JB encouraging their rationale use and translate into greater and broader utilization of JB

    SARAS 2: A Spectral Radiometer for probing Cosmic Dawn and the Epoch of Reionization through detection of the global 21 cm signal

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    The global 21 cm signal from Cosmic Dawn (CD) and the Epoch of Reionization (EoR), at redshifts z630z \sim 6-30, probes the nature of first sources of radiation as well as physics of the Inter-Galactic Medium (IGM). Given that the signal is predicted to be extremely weak, of wide fractional bandwidth, and lies in a frequency range that is dominated by Galactic and Extragalactic foregrounds as well as Radio Frequency Interference, detection of the signal is a daunting task. Critical to the experiment is the manner in which the sky signal is represented through the instrument. It is of utmost importance to design a system whose spectral bandpass and additive spurious can be well calibrated and any calibration residual does not mimic the signal. SARAS is an ongoing experiment that aims to detect the global 21 cm signal. Here we present the design philosophy of the SARAS 2 system and discuss its performance and limitations based on laboratory and field measurements. Laboratory tests with the antenna replaced with a variety of terminations, including a network model for the antenna impedance, show that the gain calibration and modeling of internal additives leave no residuals with Fourier amplitudes exceeding 2~mK, or residual Gaussians of 25 MHz width with amplitudes exceeding 2~mK. Thus, even accounting for reflection and radiation efficiency losses in the antenna, the SARAS~2 system is capable of detection of complex 21-cm profiles at the level predicted by currently favoured models for thermal baryon evolution.Comment: 44 pages, 17 figures; comments and suggestions are welcom

    OPTIMIZATION OF IRBESARTAN TABLET FORMULATION BY 23 FACTORIAL DESIGN

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    Irbesartan, a widely prescribed anti hypertensive drug belongs to class II under BCS classification and exhibit low and variable oral bioavailability due to its poor aqueous solubility. It needs enhancement in the dissolution rate in its formulation development. Complexation with β-cyclodextrin (βCD) and use of Crospovidone and PVP K 30 are tried for enhancing the dissolution rate of irbesartan in its formulation development. The objective of the present study is optimization of irbesartan tablet formulation employing Crospovidone, βCD and PVP K 30 by 23 Factorial design. Formulation of irbesartan tablets with NLT 85% dissolution in 15 min employing Crospovidone, βCD and PVP K 30 was optimized by 23 Factorial design. Eight irbesartan tablet formulations were prepared using selected combinations of the three Factors as per 23 Factorial designs. Irbesartan tablets were prepared by direct compression method and were evaluated for drug content, hardness, friability, disintegration time and dissolution rate characteristics. The dissolution rate (K1) values were analysed as per ANOVA of 23 Factorial design to find the significance of the individual and combined effects of the three Factors (βCD, Crospovidone and PVP K 30) involved on the dissolution rate of irbesartan tablets formulated. The individual and combined effects of βCD, Crospovidone and PVP K 30 on the dissolution rate (K1) of irbesartan tablets are highly significant (P<0.01). Irbesartan tablet formulation (PFac), disintegrated rapidly with in 1 min and gave very rapid dissolution of irbesartan,100% in 15 min. Higher levels of βCD and lower levels of Crospovidone gave low dissolution rates of irbesartan tablets. The increasing order of dissolution rate (K1) observed with various formulations was CFac> CFa>CFab>CFabc> CF1> CFbc> CFb> CFc. The polynomial equation describing the relationship between the response i. e. percent drug dissolved in 15 min (Y) and the levels of Crospovidone (X1),βCD (X2) and PVP K 30 (X3) based on the observed results is Y = 58.57+34.54 (X1) - 1.89(X2) – 3.60 (X1 X2) -1.82 (X3) +1.50 (X1 X3) + 3.13 (X2 X3) - 4.87 (X1 X2 X3). Based on the above polynomial equation, the optimized irbesartan tablet formulation with NLT 85% dissolution in 15 min could be formulated employing Crospovidone at 27.70% of drug content, βCD at 1:4 ratio of drug: βCD and PVP K 30 at 1% of drug content. The optimized irbesartan tablet formulation gave 86.18 % dissolution in 15 min fulfilling the target dissolution set. The dissolution profile of the optimized Irbesartan tablet formulation was similar to that of commercial brand (IROVEL-150). Hence the formulation of irbesartan tablets with NLT 85% dissolution in 15 min could be optimized by 23 Factorial design
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