38 research outputs found

    Effects of MoO 3 Addition on Spectroscopic Properties of Lithium Zinc Borate Glass

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    Abstract The paper deals with the spectroscopic properties of Li 2 O -ZnO-B 2 O 3 glass containing different concentrations of MoO 3 (ranging from 1 to 5 mol %) were prepared by melt quenching. Spectroscopic (infrared, optical absorption spectra and ESR) properties of these glasses have been carried out. The Optical absorption Spectrum contains one broad absorption band at 681 nm, this attributed to the excitation of Mo 5+ (4d 1 ) ion. ESR studies reveal Molybdenum ions are expected to exist mainly in the Mo 6+ state in the glass network. As the concentration of MoO 3 is increased, especially beyond 5.0 mol %, the colour of the glasses increased, that indicating the reduction of molybdenum ions from the Mo 6+ state to the Mo 5+ state. ESR, IR and Optical absorption spectra of paramagnetic ion in the above glasses reveal that the site symmetry of the transition metal ion is elongated octahedral

    Privacy Control In Social Networks By Trust Aware Link Prediction

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    Social networks are exceedingly common in today’s society. A social network site is an online platform where people build social relations with others and share information. For the last two decades, rapid growth in the number of users and applications with these social networking sites, make the security as the most challenging issue. In this virtual environment, some greedy people intentionally perform illegal activities by accessing others’ private information. This paper proposes a novel approach to detect the illegal access of a particular’s information by using trustaware link prediction. The facebook dataset is used for experiments and the results justify the robustness andtrustworthiness of the proposed model

    Observation of planar Hall effect in topological insulator—Bi2Te3

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    Planar Hall effect (PHE) in topological insulators (TIs) is discussed as an effect that stems mostly from conduction due to topologically protected surface states. Although surface states play a critical role and are of utmost importance in TIs, our present study in Bi2Te3 thin films reflects the need for considering the bulk conduction in understanding the origin of PHE in TIs. This necessity emerges from our observation of an unconventional increase in the PHE signal with TI thickness and temperature where the bulk effect takes over. Here, we find an enhancement in the PHE amplitude by doubling the Bi2Te3 film-thickness on the Si (111) substrate—from 1.9 nΩ m in 14 quintuple layer (QL) to 3.1 nΩ m in 30 QL devices at B = 5 T. Also, the PHE amplitude in the 30 QL Bi2Te3 films grown on two different substrates, viz., Si (111) and Al2O3 (0001), shows an increase with temperature. Our experiments indicate that the contribution of bulk states to PHE in TIs could be significant. © 2021 Author(s)

    Understanding the Magnetic Microstructure through Experiments and Machine Learning Algorithms

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    Advanced machine learning techniques have unfurled their applications in various interdisciplinary areas of research and development. This paper highlights the use of image regression algorithms based on advanced neural networks to understand the magnetic properties directly from the magnetic microstructure. In this study, Co/Pd multilayers have been chosen as a reference material system that displays maze-like magnetic domains in pristine conditions. Irradiation of Ar+ ions with two different energies (50 and 100 keV) at various fluences was used as an external perturbation to investigate the modification of magnetic and structural properties from a state of perpendicular magnetic anisotropy to the vicinity of the spin reorientation transition. Magnetic force microscopy revealed domain fragmentation with a smaller periodicity and weaker magnetic contrast up to the fluence of 1014 ions/cm2. Further increases in the ion fluence result in the formation of feather-like domains with a variation in local magnetization distribution. The experimental results were complemented with micromagnetic simulations, where the variations of effective magnetic anisotropy and exchange constant result in qualitatively similar changes in magnetic domains, as observed experimentally. Importantly, a set of 960 simulated domain images was generated to train, validate, and test the convolutional neural network (CNN) that predicts the magnetic properties directly from the domain images with a high level of accuracy (maximum 93.9%). Our work has immense importance in promoting the applications of image regression methods through the CNN in understanding integral magnetic properties obtained from the microscopic features subject to change under external perturbations. © 2022 American Chemical Society. All rights reserved

    Global burden of chronic respiratory diseases and risk factors, 1990–2019: an update from the Global Burden of Disease Study 2019

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    Background: Updated data on chronic respiratory diseases (CRDs) are vital in their prevention, control, and treatment in the path to achieving the third UN Sustainable Development Goals (SDGs), a one-third reduction in premature mortality from non-communicable diseases by 2030. We provided global, regional, and national estimates of the burden of CRDs and their attributable risks from 1990 to 2019. Methods: Using data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, we estimated mortality, years lived with disability, years of life lost, disability-adjusted life years (DALYs), prevalence, and incidence of CRDs, i.e. chronic obstructive pulmonary disease (COPD), asthma, pneumoconiosis, interstitial lung disease and pulmonary sarcoidosis, and other CRDs, from 1990 to 2019 by sex, age, region, and Socio-demographic Index (SDI) in 204 countries and territories. Deaths and DALYs from CRDs attributable to each risk factor were estimated according to relative risks, risk exposure, and the theoretical minimum risk exposure level input. Findings: In 2019, CRDs were the third leading cause of death responsible for 4.0 million deaths (95% uncertainty interval 3.6–4.3) with a prevalence of 454.6 million cases (417.4–499.1) globally. While the total deaths and prevalence of CRDs have increased by 28.5% and 39.8%, the age-standardised rates have dropped by 41.7% and 16.9% from 1990 to 2019, respectively. COPD, with 212.3 million (200.4–225.1) prevalent cases, was the primary cause of deaths from CRDs, accounting for 3.3 million (2.9–3.6) deaths. With 262.4 million (224.1–309.5) prevalent cases, asthma had the highest prevalence among CRDs. The age-standardised rates of all burden measures of COPD, asthma, and pneumoconiosis have reduced globally from 1990 to 2019. Nevertheless, the age-standardised rates of incidence and prevalence of interstitial lung disease and pulmonary sarcoidosis have increased throughout this period. Low- and low-middle SDI countries had the highest age-standardised death and DALYs rates while the high SDI quintile had the highest prevalence rate of CRDs. The highest deaths and DALYs from CRDs were attributed to smoking globally, followed by air pollution and occupational risks. Non-optimal temperature and high body-mass index were additional risk factors for COPD and asthma, respectively. Interpretation: Albeit the age-standardised prevalence, death, and DALYs rates of CRDs have decreased, they still cause a substantial burden and deaths worldwide. The high death and DALYs rates in low and low-middle SDI countries highlights the urgent need for improved preventive, diagnostic, and therapeutic measures. Global strategies for tobacco control, enhancing air quality, reducing occupational hazards, and fostering clean cooking fuels are crucial steps in reducing the burden of CRDs, especially in low- and lower-middle income countries

    The global burden of cancer attributable to risk factors, 2010-19 : a systematic analysis for the Global Burden of Disease Study 2019

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    Background Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. Methods The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk-outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. Findings Globally, in 2019, the risk factors included in this analysis accounted for 4.45 million (95% uncertainty interval 4.01-4.94) deaths and 105 million (95.0-116) DALYs for both sexes combined, representing 44.4% (41.3-48.4) of all cancer deaths and 42.0% (39.1-45.6) of all DALYs. There were 2.88 million (2.60-3.18) risk-attributable cancer deaths in males (50.6% [47.8-54.1] of all male cancer deaths) and 1.58 million (1.36-1.84) risk-attributable cancer deaths in females (36.3% [32.5-41.3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20.4% (12.6-28.4) and DALYs by 16.8% (8.8-25.0), with the greatest percentage increase in metabolic risks (34.7% [27.9-42.8] and 33.3% [25.8-42.0]). Interpretation The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.Peer reviewe

    Effect of Yb3+ ions on spectroscopic and optical properties of Bi2O3–B2O3–Li2O–PbO glass system

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    Ytterbium incorporated Bi2O3–B2O3–Li2O–PbO glasses have been found to be suitable for various photonics applications. In the current article, ytterbium (0.5, 1, 1.5, 2.0 and 2.5 mol%) were assorted with Bi2O3–B2O3–Li2O–PbO glass network formed by the conventional melt-quenching process. The XRD, SEM, DTA (DSC), FTIR, Optical absorption and Photoluminescence (PL) techniques employed to explore the detailed optical and structural features of the current glass samples. The analysis of XRD and SEM results confirmed the amorphous nature and their local structural changes perceived by DTA and FTIR results. From absorption data, indirect band gap energies, UE and cut of wavelength values are calculated. It is noticed that the PL properties improved with the increasing ytterbium compositional concentrations up to the level 2.5 mol%. The calculated CIE chromaticity coordinates from PL spectra confirmed quality of the light generated from the as-systemized glasses for LASER production. The obtained experimental results supported the usefulness of the developed glasses in the field of photonics

    Influence of ZrO2_{2} Addition on Structural and Biological Activity of Phosphate Glasses for Bone Regeneration

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    Zirconium doped calcium phosphate-based bioglasses are the most prominent bioactive materials for bone and dental repair and regeneration implants. In the present study, a 8ZnO-22Na2O-(24 - x)CaO-46P2O5-xZrO2 (0.1 ≤ x ≤ 0.7, all are in mol%) bioglass system was synthesized by the conventional melt-quenching process at 1100 °C. The glass-forming ability and thermal stability of the glasses were determined by measuring the glass transition temperature (Tg), crystallization temperature (Tc), and melting temperature (Tm), using differential thermal analysis (DTA). The biological activity of the prepared samples was identified by analyzing X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy-energy dispersive spectra (SEM-EDS), before and after immersion in simulated body fluid (SBF) for various intervals of 0, 1 and 5 days, along with the magnitude of pH and the degradation of glasses also evaluated. The obtained results revealed that the glass-forming ability and thermal stability of glasses increased with the increase in zirconia mol%. The XRD, FTIR, and SEM-EDS data confirmed a thin hydroxyapatite (HAp) layer over the sample surface after incubation in SBF for 1 and 5 days. Furthermore, the development of layer found to be increased with the increase of incubation time. The degradation of the glasses in SBF increased with incubation time and decreased gradually with the increase content of ZrO2 mol% in the host glass matrix. A sudden rise in initial pH values of residual SBF for 1 day owing to ion leaching and increase of Ca2+ and PO43- ions and then decreased. These findings confirmed the suitability of choosing material for bone-related applications

    Investigations on Physico-Mechanical and Spectral Studies of Zn2+ Doped P2O5-Based Bioglass System

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    ZnO incorporated phosphate based bioglasses with the composition xZnO–22Na2O–24CaO–(54-X)P2O5 (where X = 2, 4, 6, 8, 10 mol%) were developed by melt-quenching process. The physical, thermal and other structural properties of the glasses were studied in detail. By employing various characterization techniques such as X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) in addition to the energy dispersion spectroscopy (EDS), and Raman spectroscopy, the structural properties were analyzed. Interestingly, physical, thermal and mechanical properties were enhanced with the increasing content of zinc oxide up to 8 mol%, due to the presence of more ionic nature of P–O–Zn bonds than P–O–P bonds in the glass network. The FTIR and Raman analysis revealed the evolution of the phosphate network with increasing zinc concentration and leads to progressive depolymerisation of the glass network. The obtained results from the physical and structural properties of these zinc added calcium phosphate glasses support their potential to use as bone implant applications
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