40 research outputs found

    Iterative Surrogate Model Optimization (ISMO): An active learning algorithm for PDE constrained optimization with deep neural networks

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    We present a novel active learning algorithm, termed as iterative surrogate model optimization (ISMO), for robust and efficient numerical approximation of PDE constrained optimization problems. This algorithm is based on deep neural networks and its key feature is the iterative selection of training data through a feedback loop between deep neural networks and any underlying standard optimization algorithm. Under suitable hypotheses, we show that the resulting optimizers converge exponentially fast (and with exponentially decaying variance), with respect to increasing number of training samples. Numerical examples for optimal control, parameter identification and shape optimization problems for PDEs are provided to validate the proposed theory and to illustrate that ISMO significantly outperforms a standard deep neural network based surrogate optimization algorithm

    Enantioselective Synthesis of Pladienolide B and Truncated Analogues as New Anticancer Agents

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    An enantioselective synthesis of natural anticancer macrolide pladienolide B is described. The synthetic highlights include Sharpless asymmetric epoxidation, ring closing metathesis (RCM), Ireland–Claisen rearrangement, Shi epoxidation, and Pd-catalyzed Stille coupling as key steps. The synthetic route also allowed the synthesis of the truncated analogues (<b>41a</b>–<b>d</b>) of pladienolide B

    Enantioselective Synthesis of Pladienolide B and Truncated Analogues as New Anticancer Agents

    No full text
    An enantioselective synthesis of natural anticancer macrolide pladienolide B is described. The synthetic highlights include Sharpless asymmetric epoxidation, ring closing metathesis (RCM), Ireland–Claisen rearrangement, Shi epoxidation, and Pd-catalyzed Stille coupling as key steps. The synthetic route also allowed the synthesis of the truncated analogues (<b>41a</b>–<b>d</b>) of pladienolide B

    Oxidation of alkynes using PdCl<SUB>2</SUB>/CuCl<SUB>2</SUB> in PEG as a recyclable catalytic system: one-pot synthesis of quinoxalines

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    Alkynes were oxidized efficiently using the catalytic amount of PdCl2 and CuCl2 in PEG-400 in the presence of water, providing excellent yields of the corresponding 1,2-diketones. A variety of alkynes were well-suited substrates for the oxidation under the described conditions. Further, the optimized conditions were successfully utilized for the one-pot synthesis of 2,3-disubstituted quinoxaline derivatives

    A curious case of refractory hypothyroidism due to selective malabsorption of oral thyroxine

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    There are very few cases in the literature in which refractory persistent hypothyroidism responded only to parenteral doses of levothyroxine and no evidence of any malabsorptive disorder could be identified. Here, we present a rare case of a 35-year-old woman with refractory hypothyroidism who responded only to intravenous doses of levothyroxine. We also discuss possible causes for the same

    Incidental detection of hyperfunctioning thyroid cancer metastases in patients presenting with thyrotoxicosis

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    Thyrotoxicosis due to functioning metastases from thyroid cancer is rare. It also presents a therapeutic challenge, as both the metastatic cancer and thyrotoxicosis need to be treated. We present here two cases of thyrotoxicosis which on a routine 99m Tc-pertechnetate thyroid scan showed extrathyroidal foci of uptake. Two patients who initially presented with thyrotoxicosis underwent a routine thyroid scan. Abnormal uptake in the shoulder was incidentally noted, which prompted us to do a whole body pertechnetate scan in the same sitting, which revealed extensive hyperfunctioning metastases in the lungs and bones. We also discuss the ′Flip Flop′ phenomenon in thyroid cancer, which was seen in our case. This report emphasizes the importance of evaluating the abnormal foci of uptake seen on a routine thyroid scan

    PHARMACOLOGICAL EVALUATION OF ANTIDEPRESSANT ACTIVITY OF AQUEOUS EXTRACT OF ROSA CENTIFOLIA PETALS IN MICE

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    ABSTRACT To study the antidepressant activity with aqueous extract of Rosa centifolia. The extract was primarily subjected for preliminary phytochemical investigation and for Maximum Tolerance Dose (MTD). Antidepressant activity was evaluated in various animal models like Forced swim test, Tail suspension test, Apomorphine induced hypothermia and 5-HTP potentiation of head twitches in mice. The aqueous extract of Rosa centifolia was positively identified with carbohydrates, tannins, proteins, amino acids, alkaloids, flavonoids, flavanone, glycosides and phenolic compounds. The extract was subjected for maximum tolerance dose upto the dose level of 2000mg/kg has not produced any mortality. The extract of Rosa centifolia showed significant antidepressant activity at high dose (100 mg/kg) in Tail suspension test, Forced swim test and Potentiation of 5-HTP induced head twitches. The extract didn&apos;t antagonized the hypothermia induced by apomorphine

    Dental patient anxiety: Possible deal with Lavender fragrance

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    Objective: The pure essence of plants (essential oils) provides both psychological and physiological benefits when used accurately and safely. Conventionally, Lavender oil is known for relaxing, carminative, and sedative effects. Hence, an attempt was made to know the effect of Lavender essential oil on dental patient anxiety. Methods: The present study included two comparison groups (Lavender and control group), each comprising five dental clinics. In Lavender group, the ambient odor of Lavender essential oil was maintained with the help of a candle warmer in the reception area and in the control group, candle warmer with normal water was used. A total of 597 patients, aged above 18 years were included. A questionnaire comprising demographic information, and a modified dental anxiety scale was given to the patients in waiting room, and data regarding anxiety levels was recorded. Findings: Student′s t-test (unpaired) showed a significant reduction in anxiety scores of Lavender group compared with the control group. Analysis of variances test showed reduction in anxiety scores as age increased in Lavender group. Conclusion: Fragrance of Lavender oil at reception area may effectively reduce the patient′s state or current anxiety. This practice on routine usage can improve the quality of dental treatments

    Synthesis of α-amino amidines through molecular iodine-catalyzed three-component coupling of isocyanides, aldehydes and amines

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    A facile and efficient synthetic protocol for the synthesis of α-amino amidines has been developed using a molecular iodine-catalyzed three-component coupling reaction of isocyanides, amines, and aldehydes. The presented strategy offers the advantages of mild reaction conditions, low environmental impact, clean and simple methodology, high atom economy, wide substrate scope and high yields
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