20 research outputs found
Modelling UV response of biomolecules: from electronic structure to ab-initio dynamics.
The interaction of organic chromophores with light initiates ultrafast processes in the timescale of femtoseconds. An atomistic understanding of the mechanism driving such photoinduced reactions opens up the door to exploit them for our benefit. This thesis studies the interactions of ultraviolet light with the DNA/RNA molecules and the amino-acid tryptophan. Using some of the most accurate electronic structure methods and sophisticated environmental modelling, the works documented herein enable quantitative comparisons with cutting-edge experimental data. The relaxation pathways undertaken by the excited molecule are revealed through static and dynamical investigations of the excited-state potential energy surface. The profound role played by the dynamic response of the environment to guide the excitation in these timescales is addressed thoroughly
Maximizing Savonius Turbine Performance using Kriging Surrogate Model and Grey Wolf-Driven Cylindrical Deflector Optimization
With the growing demand for power and the pressing need to shift towards
renewable energy sources, wind power stands as a vital component of the energy
transition. To optimize energy production, researchers have focused on design
optimization of Savonius-type vertical axis wind turbines (VAWTs). The current
study utilizes Unsteady Reynolds-Averaged Navier Stokes (URANS) simulations
using the sliding mesh technique to obtain flow field data and power
coefficients. A Kriging Surrogate model was trained on the numerical data of
randomly initialized data points to construct a response surface model. Then
Grey Wolf Optimization (GWO) algorithm was utilized to achieve global maxima on
this surface, using the turbine's power coefficient as the objective function.
A comparative analysis was carried out between simulation and experimental data
from prior studies to validate the accuracy of the numerical model. The
optimized turbine-deflector configuration showed a maximum improvement of
34.24% in power coefficient. Additionally, the GWO algorithm's effectiveness
was compared with Particle Swarm Optimization (PSO) and was found to be better
in most cases, converging towards the global maxima faster. This study explores
a relatively unexplored realm of metaheuristic optimization of wind turbines by
using deflectors, for efficient energy harvesting, presenting promising
prospects for enhancing renewable power generation.Comment: Accepted at 10th International and 50th National Conference on Fluid
Mechanics and Fluid Power (FMFP-2023): 6 pages, 12 figure
Environment-Driven Coherent Population Transfer Governs the Ultrafast Photophysics of Tryptophan
: By combining UV transient absorption spectroscopy with sub-30-fs temporal resolution and CASPT2/MM calculations, we present a complete description of the primary photoinduced processes in solvated tryptophan. Our results shed new light on the role of the solvent in the relaxation dynamics of tryptophan. We unveil two consecutive coherent population transfer events involving the lowest two singlet excited states: a sub-50-fs nonadiabatic La → Lb transfer through a conical intersection and a subsequent 220 fs reverse Lb → La transfer due to solvent-assisted adiabatic stabilization of the La state. Vibrational fingerprints in the transient absorption spectra provide compelling evidence of a vibronic coherence established between the two excited states from the earliest times after photoexcitation and lasting until the back-transfer to La is complete. The demonstration of response to the environment as a driver of coherent population dynamics among the excited states of tryptophan closes the long debate on its solvent-assisted relaxation mechanisms and extends its application as a local probe of protein dynamics to the ultrafast time scales
The OpenMolcas Web: A Community-Driven Approach to Advancing Computational Chemistry
The developments of the open-source OpenMolcas chemistry software environment since spring 2020 are described, with a focus on novel functionalities accessible in the stable branch of the package or via interfaces with other packages. These developments span a wide range of topics in computational chemistry and are presented in thematic sections: electronic structure theory, electronic spectroscopy simulations, analytic gradients and molecular structure optimizations, ab initio molecular dynamics, and other new features. This report offers an overview of the chemical phenomena and processes OpenMolcas can address, while showing that OpenMolcas is an attractive platform for state-of-the-art atomistic computer simulations
The global burden of cancer attributable to risk factors, 2010-19 : a systematic analysis for the Global Burden of Disease Study 2019
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
Recommended from our members
Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation
Recommended from our members
Untangling the multi-regime molecular mechanism of verbenol-chemotype Zingiber officinale essential oil against Aspergillus flavus and aflatoxin B1.
Aflatoxin B1 (AFB1), the natural polyketide produced by Aspergillus flavus, has a potent carcinogenic effect on humans as well as animals. In the present study, the antifungal and anti-aflatoxigenic B1 activity of chemically characterized Zingiber officinale essential oil (ZOEO) was investigated via in vitro analysis aided with molecular dynamics (MD) approaches. The GC-MS results revealed verbenol (52.41%) as the major component of oil. The antifungal and anti-aflatoxigenic activity of ZOEO was found to be 0.6 µl/ml and 0.5 µl/ml respectively. In-vitro analysis targeting the cell membrane, mitochondria and carbohydrate catabolism elucidated the probable antifungal mode of action. Further, docking and MD simulation results confirmed the inhibitory action of verbenol on the structural gene products (Nor-1, Omt-1, and Vbs) of aflatoxin biosynthetic machinery. Biochemical assays revealed the fungitoxic potential of the ZOEO while, computational results infers the stabilizing effects on the gene products upon verbenol binding leads to the impairment in its functionality. This is the first attempt to assess the multi-regime anti-AFB1 mechanism of verbenol chemotype-ZOEO targeting the Nor-1, Omt-1, and Vbs via computational approaches
Unified Description of Ultrafast Excited State Decay Processes in Epigenetic Deoxycytidine Derivatives
none8siEpigenetic DNA modifications play a fundamental role in modulating
gene expression and regulating cellular and developmental biological processes, thereby
forming a second layer of information in DNA. The epigenetic 2′-deoxycytidine
modification 5-methyl-2′-deoxycytidine, together with its enzymatic oxidation products (5-hydroxymethyl-2′-deoxycytidine, 5-formyl-2′-deoxycytidine, and 5-carboxyl-2′-deox-
ycytidine), are closely related to deactivation and reactivation of DNA transcription.
Here, we combine sub-30-fs transient absorption spectroscopy with high-level
correlated multiconfigurational CASPT2/MM computational methods, explicitly
including the solvent, to obtain a unified picture of the photophysics of
deoxycytidine-derived epigenetic DNA nucleosides. We assign all the observed time
constants and identify the excited state relaxation pathways, including the competition
of intersystem crossing and internal conversion for 5-formyl-2′-deoxycytidine and
ballistic decay to the ground state for 5-carboxy-2′-deoxycytidine. Our work contributes
to shed light on the role of epigenetic derivatives in DNA photodamage as well as on their possible therapeutic use.openKabaciński, Piotr; Romanelli, Marco; Ponkkonen, Eveliina; Jaiswal, Vishal Kumar; Carell, Thomas; Garavelli, Marco; Cerullo, Giulio; Conti, IreneKabaciński, Piotr; Romanelli, Marco; Ponkkonen, Eveliina; Jaiswal, Vishal Kumar; Carell, Thomas; Garavelli, Marco; Cerullo, Giulio; Conti, Iren
Magnetron configurations dependent surface properties of SnO2 thin films deposited by sputtering process
The effect of balanced magnetron (BM) and unbalanced magnetron (UBM) configurations, in RF sputtering process, on the surface properties of SnO2 thin films has been investigated. X-ray photoelectron spectroscopy (XPS) Sn3d and O1s core spectra reveal that the films deposited at RF power of 250 W under BM configuration consist of Sn4+ oxidation states, while those deposited under UBM configuration consist of Sn4+ and Sn2+ oxidation states. This has been attributed to the migration of oxygen atoms from SnO2, resulting in the formation of Sn interstitial and oxygen vacancies. The contact angle (theta) recordings reveal that the UBM configuration results in more hydrophobic surface (140.6 degrees) of SnO2 thin films than that under BM configuration (129.6 degrees). Further, Atomic Force Microscopy (AFM) and Field Emission Scanning Electron Microscopy (FESEM) results indicate that the SnO2 thin films deposited under UBM configuration have better density with granular grains in comparison to that under BM configuration. The present studies establish the fact that magnetron configurations in sputtering process have significant impact on the surface properties of SnO2 thin films