62 research outputs found

    The Exact Potential Driving the Electron Dynamics in Enhanced Ionization

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    It was recently shown that the exact factorization of the electron-nuclear wavefunction allows the construction of a Schr\"odinger equation for the electronic system, in which the potential contains exactly the effect of coupling to the nuclear degrees of freedom and any external fields. Here we study the exact potential acting on the electron in charge-resonance enhanced ionization in a model one-dimensional H2+_2^+ molecule. We show there can be significant differences between the exact potential and that used in the traditional quasistatic analyses, arising from non-adiabatic coupling to the nuclear system, and that these are crucial to include for accurate simulations of time-resolved ionization dynamics and predictions of the ionization yield

    Electronic non-adiabatic dynamics in enhanced ionization of isotopologues of hydrogen molecular ions from the exact factorization perspective

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    It was recently shown that the exact potential driving the electron's dynamics in enhanced ionization of H-2(+) can have large contributions arising from dynamic electron-nuclear correlation, going beyond what any Coulombic-based model can provide. This potential is defined via the exact factorization of the molecular wavefunction that allows the construction of a Schro "dinger equation for the electronic system, in which the potential contains exactly the effect of coupling to the nuclear system and any external fields. Here we study enhanced ionization in isotopologues of H-2(+) in order to investigate the nuclear-mass-dependence of these terms for this process. We decompose the exact potential into components that naturally arise from the conditional wavefunction, and also into components arising from the marginal electronic wavefunction, and compare the performance of propagation on these different components as well as approximate potentials based on the quasi-static or Hartree approximation with the exact propagation. A quasiclassical analysis is presented to help analyse the structure of different non-Coulombic components of the potential driving the ionizing electron.We acknowledge support from the European Research Council (ERC-2015-AdG-694097), Grupos Consolidados (IT578-13), and the European Union's Horizon 2020 Research and Innovation programme under grant agreement no. 676580. A. K. and A. A. acknowledge funding from the European Union's Horizon 2020 research and innovation programme under the Marie SklodowskaCurie grant agreement no. 704218 and 702406, respectively. N. T. M. thanks the National Science Foundation, grant CHE1566197, for support. Open Access funding provided by the Max Planck Society

    Identifying finance strategies in central libraries of public universities in Tehran

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    Objective: The purpose of this study is to identify financing strategies in Tehran central library of public universities. Methods: This study in terms of implementation is library then survey, and data collection tools are study texts then a researcher made questionnaire. First, the current status of libraries in terms of funding from the heads or deputies or their representatives point of view is discussed. Then the questionnaires were distributed among the managers and librarians to inform us about their viewpoint about financing strategies. To measure the current situation the study population consisted of all managers and heads of 11 academic universities and the attitude assessment was in a census method. A total of 156 librarians responded to the questionnaires. The analysis of the findings of this study has been done through SPSS. Findings: The findings of the study show that the current strategies used to finance in the central libraries of academic universities of Tehran are not appropriate to the current situation. Besides, it was founded that there is a significant relationship between the main variables of the research, namely financing strategies, and its dimensions, and income-generating activities, financing methods, and training in the financing, respectively, have the greatest impact on financing strategies in university central libraries. Originality: This study for the first time examines the approach of financing in Tehran public university libraries in addition, using the perspectives of managers and librarians, offers some guidelines for financing in academic libraries

    Evaluation of Canal Transportation and Centering Ability of RaCe and Af f-one Systems by Cone-beam Computed Tomography: An in Vitro Study

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    Introduction Rotary systems have made significant advances to improve their root canal preparation efficacy. These instruments can properly preserve the root canal anatomy and morphology. The present in vitro study aimed to compare canal transportation and centering ability of RaCe and Af f-one systems using cone-beam computed tomography. Materials and Methods: Thirty-six mandibular molars were included. The samples were randomly assigned to two groups (n=18): group 1, RaCe, and group 2, Af f-one. Canal preparation was conducted using the respective files according to the manufacturers’ instructions. The cone-beam computed tomographic scanning of the samples was performed before and after preparation. The data were analyzed by using two-way ANOVA. Results: In both the RaCe and Af f-one rotary systems, canal centrality and transportation were similar at coronal, middle, and apical cross-sections. In addition, canal transportation and centrality were identical in the RaCe and Af f-one rotary files (P<0.05). Conclusion: The two studied rotary systems did not exhibit significant differences in root canal transportation and preservation of root canal centrality in the apical, middle, and coronal thirds

    The Effect of Group Prenatal Care on Empowerment of Pregnant Adolescents: A randomized controlled trial

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    Objectives: This study aimed to evaluate the effect of group prenatal care on empowerment of pregnant adolescents. Methods: In this randomized controlled trial, 294 pregnant adolescents (aged 15-19) were randomly assigned into two groups of group prenatal care (GPNC, n=147) and individual prenatal care (IPNC, n=147). GPNC group received 5 sessions of GPNC (90-120 min) during 16-20 weeks of pregnancy, while the control group received individual prenatal care. The empowerment of participants in the two groups was measured using the empowerment scale for pregnant women. Data were analyzed using the Chi-square test, independent t-test, and adjusted regression test. Results: The mean total score of pregnant women’s empowerment in the GPNC and IPNC groups after the intervention was 86.46±4.95 and 81.89±4.75, respectively [ β= 6.11, 95% CI: 4.89, 7.33, p<0.0001]. The improvement of dimensions of pregnancy empowerment in GPNC versus IPNC was as follows: Self‐efficacy: 18.21 ± 2.12 vs. 16.19 ± 1.79 [β= 2.52, 95% CI: 2.19, 2.86, p<0.0001], Future image: 19.57±1.57 vs. 18.95±1.54 [β= 0.67, 95% CI: (0.44, 0.9], Self-esteem: 21.79 ± 1.75 vs. 20.90 ± 1.85 [β= 0.69, 95% CI: 0.41, 0.97, P<0.0001], Joy of an addition to the family: 13.13±1.69 vs. 12.84±1.40 [β= 0.51, 95% CI: 0.28, 0.74, P=0.009], and Support and assurance from others: 13.70 ± 1.1 and 13.04 ± 1.07, [β= 0.76, 95% CI: 0.13, 1.65, P<0.0001]. Conclusion: Group prenatal care can improve adolescent pregnant women’s empowerment. Results of the present study can serve as a useful foundation for implementing the group prenatal care model in Iran. Keywords: Adolescent pregnancy; Empowerment; Centering prenatal care; Group prenatal care; Ira

    Potential role of saffron and its components on miRNA levels in various disorders, a comprehensive review

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    The potential therapeutic benefits of saffron and its active constituents have been investigated for the treatment of numerous illnesses. In this review, the impacts of saffron and its essential components on the levels of microRNAs (miRNAs) in different diseases have been delineated. Relevant articles were obtained through databases such as PubMed, Web of Sciences, Scopus, and Google Scholar up to the end of November 2022. miRNA expression has been altered by saffron and its active substances (crocin, crocetin, and safranal) which has been of great advantage in treating diseases such as cardiovascular, type 2 diabetes, cancers, gastrointestinal and liver disorders, central and peripheral nervous system disorders, asthma, osteoarthritis, ischemic-reperfusion induced injury conditions, and renal disorder. This study uncovered the potential restorative advantages of saffron and its derivatives, in miRNA imbalances in a variety of diseases

    Nutrition and osteoporosis prevention and treatment

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    Introduction: Osteoporosis falls among the major general health issues, specifically in the elderly, and is a widespread disease these days. According to various studies, good nutrition plays a significant role in osteoporosis prevention and treatment. The aim of this study was to conduct an extensive literature review on the effects of different nutrients to understand how macronutrients, micronutrients, and non-nutritive substances affect bone health. Methodology: To find relevant studies, the main keyword "osteoporosis" was searched in combination with "zinc," "vitamin K," "phosphorus," "vitamin D," "calcium," "lipid," "protein," and "phytoestrogens" in PubMed (MEDLINE), Web of Science, SID, and Iran Medex databases. Findings: The most important element for bone health is calcium, which has a direct link to the bone mass density (BMD). In the case of calcium deficiency, high phosphorus content can damage bone tissue. The acceptable ratio of phosphorus to calcium is 0.5-1.5:1. Vitamin D is another important nutrient for bones; serum levels of vitamin D less than 20 ng/ml reduce bone density and increase the risk of fracture. High protein intake results in calcium excretion and loss of bone mass. In addition, calcium deficiency increases the risk of osteoporosis, specifically in the elderly. According to the literature, there is an inverse correlation between saturated fats and BMD. Vitamin K and magnesium deficiencies are correlated with BMD reduction and increased risk of osteoporosis. Copper and zinc are used as co-factors in the formation of collagen and elastin, and in mineralization of bone. As a result, deficiency of these elements may disrupt the process of incorporating minerals into the bone matrix. Conclusion: Good nutrition may play a significant role in osteoporosis prevention and treatment. Indeed, a healthy diet containing calcium (1,200 mg/day); vitamin D (600 IU); and certain amounts of protein, magnesium, and vitamin K can contribute greatly to bone health

    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
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