79 research outputs found

    Evaluation of third order nonlinear optical properties of SiO2/PVA-PEG Nanocomposites by Z-Scan Method

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    23-27SiO2 nanoparticles was synthesized by sol-gel method and polymer nanocomposites by solvo-casting method. XRD and SEM analysis have revealed the size, morphological structure and formation of SiO2/PVA-PEG polymer nanocomposites. The presence of hydrogen bond between SiO2 and PVA-PEG was proved with the help of Fourier Transform Infra Red Spectroscopy (FTIR). Further UV-Vis studies were used to find the optical band gap and linear refractive index. Third order nonlinear optical properties such as two photon absorption, nonlinear refractive index and third order nonlinear susceptibility was evaluated for the title compound using Z-scan method. The estimated nonlinear optical properties of title compound proved the appropriateness of the sample for optical applications

    Evaluation of third order nonlinear optical properties of SiO2/PVA-PEG Nanocomposites by Z-Scan Method

    Get PDF
    SiO2 nanoparticles was synthesized by sol-gel method and polymer nanocomposites by solvo-casting method. XRD and SEM analysis have revealed the size, morphological structure and formation of SiO2/PVA-PEG polymer nanocomposites. The presence of hydrogen bond between SiO2 and PVA-PEG was proved with the help of Fourier Transform Infra Red Spectroscopy (FTIR). Further UV-Vis studies was used to find the optical band gap and linear refractive index. Third order nonlinear optical properties such as two photon absorption, nonlinear refractive index and third order nonlinear susceptibility was evaluated for the title compound using Z-scan method. The estimated nonlinear optical properties of title compound proved the appropriateness of the sample for optical applications

    History on the biological nitrogen fixation research in graminaceous plants: special emphasis on the Brazilian experience

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    PANC Study (Pancreatitis: A National Cohort Study): national cohort study examining the first 30 days from presentation of acute pancreatitis in the UK

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    Abstract Background Acute pancreatitis is a common, yet complex, emergency surgical presentation. Multiple guidelines exist and management can vary significantly. The aim of this first UK, multicentre, prospective cohort study was to assess the variation in management of acute pancreatitis to guide resource planning and optimize treatment. Methods All patients aged greater than or equal to 18 years presenting with acute pancreatitis, as per the Atlanta criteria, from March to April 2021 were eligible for inclusion and followed up for 30 days. Anonymized data were uploaded to a secure electronic database in line with local governance approvals. Results A total of 113 hospitals contributed data on 2580 patients, with an equal sex distribution and a mean age of 57 years. The aetiology was gallstones in 50.6 per cent, with idiopathic the next most common (22.4 per cent). In addition to the 7.6 per cent with a diagnosis of chronic pancreatitis, 20.1 per cent of patients had a previous episode of acute pancreatitis. One in 20 patients were classed as having severe pancreatitis, as per the Atlanta criteria. The overall mortality rate was 2.3 per cent at 30 days, but rose to one in three in the severe group. Predictors of death included male sex, increased age, and frailty; previous acute pancreatitis and gallstones as aetiologies were protective. Smoking status and body mass index did not affect death. Conclusion Most patients presenting with acute pancreatitis have a mild, self-limiting disease. Rates of patients with idiopathic pancreatitis are high. Recurrent attacks of pancreatitis are common, but are likely to have reduced risk of death on subsequent admissions. </jats:sec
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