| 1. |
- Abbas, Ghulam, et al.
(författare)
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Quasi Three-Dimensional Tetragonal SiC Polymorphs as Efficient Anodes for Sodium-Ion Batteries
- 2023
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Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 6:17, s. 8976-8988
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Tidskriftsartikel (refereegranskat)abstract
- In the present work, we investigate, for the first time, quasi 3D porous tetragonal silicon–carbon polymorphs t(SiC)12 and t(SiC)20 on the basis of first-principles density functional theory calculations. The structural design of these q3-t(SiC)12 and q3-t(SiC)20 polymorphs follows an intuitive rational approach based on armchair nanotubes of a tetragonal SiC monolayer where C–C and Si–Si bonds are arranged in a paired configuration for retaining a 1:1 ratio of the two elements. Our calculations uncover that q3-t(SiC)12 and q3-t(SiC)20 polymorphs are thermally, dynamically, and mechanically stable with this lattice framework. The results demonstrate that the smaller polymorph q3-t(SiC)12 shows a small band gap (∼0.59 eV), while the larger polymorph of q3-t(SiC)20 displays a Dirac nodal line semimetal. Moreover, the 1D channels are favorable for accommodating Na ions with excellent (>300 mAh g–1) reversible theoretical capacities. Thus confirming potential suitability of the two porous polymorphs with an appropriate average voltage and vanishingly small volume change (<6%) as anodes for Na-ion batteries.
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| 2. |
- Abdal, Noman, et al.
(författare)
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Salinity mitigates cadmium-induced phytotoxicity in quinoa (Chenopodium quinoa Willd.) by limiting the Cd uptake and improved responses to oxidative stress : implications for phytoremediation
- 2023
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Ingår i: Environmental Geochemistry and Health. - : Springer Science and Business Media LLC. - 0269-4042 .- 1573-2983. ; 45:1, s. 171-185
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Tidskriftsartikel (refereegranskat)abstract
- Cadmium (Cd) contamination and soil salinity are the main environmental issues reducing crop productivity. This study aimed to examine the combined effects of salinity (NaCl) and Cd on the physiological and biochemical attributes of quinoa (Chenopodium quinoa Willd.). For this purpose, 30-day-old plants of quinoa genotype “Puno” were transplanted in Hoagland's nutrient solution containing diverse concentrations of Cd: 0, 50, 100, 200 µM Cd, and salinity: 0, 150, and 300 mM NaCl. Results demonstrated that plant growth, stomatal conductance, and pigment contents were significantly lower at all Cd concentrations than the control plants. Quinoa plants exhibited improved growth and tolerance against Cd when grown at a lower level of salinity (150 mM NaCl) combined with Cd. In contrast, the elevated concentration of salinity (300 mM NaCl) combined with Cd reduced shoot and root growth of experimental plants more than 50%. Combined application of salinity and Cd increased Na (25-fold), while lessened the Cd (twofold) and K (1.5-fold) uptake. A blend of high concentrations of Na and Cd caused overproduction of H2O2 (eightfold higher than control) contents and triggered lipid peroxidation. The activities of antioxidant enzymes: ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) were 13, 12, 7 and ninefold higher than control to mitigate the oxidative stress. Due to restricted root to shoot translocation, and greater tolerance potential against Cd, the quinoa genotype, Puno, is suitable for phytostabilization of Cd in saline soils.
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| 3. |
- Ahmed, Shahbaz, et al.
(författare)
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Accurate First-Principles Evaluation of Structural, Electronic, Optical and Photocatalytic Properties of BaHfO3 and SrHfO3 Perovskites
- 2022
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Ingår i: Journal of Alloys and Compounds. - : Elsevier. - 0925-8388 .- 1873-4669. ; 892
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Tidskriftsartikel (refereegranskat)abstract
- A reliable first-principles account of experimentally observed physical properties of perovskite oxides is crucial for realizing their employment in electronic and optical devices. In this context, SCAN meta-GGA functional of DFT offers good approximation for the exchange-correlation energy; facilitating accurate determination of structural and energetic properties. However, SCAN is unable to reproduce electronic and optical properties of wide bad gap materials. In the present study, we report systematic DFT calculations to show that structural, energetic, electronic and optical properties of hafnium based BaHfO3 and SrHfO3 perovskite oxides can be accurately determined through a combine application of SCAN and Tran-Blaha modified Becke-Johnson (TB-mBJ) meta-GGAs. The structural and energetic properties computed using SCAN functional for both BaHfO3 and SrHfO3 are found to be in good agreement with experimental data; achieving a level of accuracy comparable to computationally expansive hybrid DFT calculations. On the other hand, TB-mBJ calculated band gaps computed using the SCAN optimized lattice parameters provide better agreement with experimental data at a low computational cost. The optical properties, band edge potentials and effective masses of the charge carriers in BaHfO3 and SrHfO3 are also computed to examine the combined application of SCAN and TB-mBJ meta-GGAs in predicting the photocatalytic performance of these wide band gap materials. Our results clearly show that the combination of the two meta-GGAs provide a computationally economical route for evaluating the photocatalytic performance of alkaline-earth metal hafnates.
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| 4. |
- Alay-e-Abbas, Syed Muhammad, 1983-, et al.
(författare)
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Structure inversion asymmetry enhanced electronic structure and electrical transport in 2D A3SnO (A = Ca, Sr, and Ba) anti-perovskite monolayers
- 2023
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Ingår i: Nano Reseach. - : Springer Nature. - 1998-0124 .- 1998-0000. ; 16:1, s. 1779-1791
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Tidskriftsartikel (refereegranskat)abstract
- Anti-perovskites A3SnO (A = Ca, Sr, and Ba) are an important class of materials due to the emergence of Dirac cones and tiny mass gaps in their band structures originating from an intricate interplay of crystal symmetry, spin-orbit coupling, and band overlap. This provides an exciting playground for modulating their electronic properties in the two-dimensional (2D) limit. Herein, we employ first-principles density functional theory (DFT) calculations by combining dispersion-corrected SCAN + rVV10 and mBJ functionals for a comprehensive side-by-side comparison of the structural, thermodynamic, dynamical, mechanical, electronic, and thermoelectric properties of bulk and monolayer (one unit cell thick) A3SnO anti-perovskites. Our results show that 2D monolayers derived from bulk A3SnO anti-perovskites are structurally and energetically stable. Moreover, Rashba-type splitting in the electronic structure of Ca3SnO and Sr3SnO monolayers is observed owing to strong spin-orbit coupling and inversion asymmetry. On the other hand, monolayer Ba3SnO exhibits Dirac cone at the high-symmetry Γ point due to the domination of band overlap. Based on the predicted electronic transport properties, it is shown that inversion asymmetry plays an essential character such that the monolayers Ca3SnO and Sr3SnO outperform thermoelectric performance of their bulk counterparts.
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| 5. |
- Bilal, Muhammad, et al.
(författare)
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DFT insights into surface properties of anti-perovskite 3D topological crystalline insulators : A case study of (001) surfaces of Ca3SnO
- 2021
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Ingår i: Physics Letters A. - : Elsevier. - 0375-9601 .- 1873-2429. ; 408
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Tidskriftsartikel (refereegranskat)abstract
- In this letter density functional theory calculations are used for investigating the structural, energetic and electronic properties of CaSn- and Ca2O-terminated (001) surfaces of anti-perovskite Ca3SnO. Our calculations indicate larger structural changes in case of the CaSn-terminated (001) surface of Ca3SnO, however, both CaSn- and Ca2O-terminated surfaces of Ca3SnO are found to be energetically stable. The electronic properties of (001) surfaces of Ca3SnO are examined by taking spin-orbit coupling into account. Comparison of the simulated results of electronic properties for the two (001) surfaces of Ca3SnO with experimentally reported hole carrier densities observed in p-type polycrystalline samples show good agreement.
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| 6. |
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| 7. |
- Saeed, Aamer, et al.
(författare)
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Identification of novel C-2 symmetric Bis-Azo-Azamethine molecules as competitive inhibitors of mushroom tyrosinase and free radical scavengers : synthesis, kinetics, and molecular docking studies
- 2022
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Ingår i: Journal of Biomolecular Structure and Dynamics. - : Taylor & Francis. - 0739-1102 .- 1538-0254. ; 40:10, s. 4419-4428
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Tidskriftsartikel (refereegranskat)abstract
- Tyrosinase is a multi-copper enzyme found in plants, animals and microorganisms, plays a critical role in the melanogenesis and browning process critical to cosmetics and food industries. Many natural, semi-synthetic and synthetic inhibitors have been discovered. To this end, a small library of symmetrical Bis-Azo-Azamethine hybrids 5a–j was synthesized and characterized through spectroscopic and analytical data and explored for mushroom tyrosinase and free radical scavenging activity. All of the molecules 5a–j explicated better potential compared to the standard Kojic acid. On the whole, compound 5i having IC50 value 0.002 ± 0.004 µM was found to be the most potent derivative. The Kinetic studies were performed for 5i and indicating the mode of inhibition in a competitive manner. Structure Activity Relationship (SAR) analysis and docking studies were carried out. Thus compound 5i bearing bulky naphthyl groups was most potent and, The molecular docking indicated formation of two hydrogen bonds with Arg268 and one hydrophobic interaction with Glu322. The carbonyl oxygen of 5i interacts with Arg268 and form two hydrogen bonds having lengths 2.44 and 2.62 Å, respectively. In the same way, compounds 5a–j were appraised for DPPH free radical scavenging ability and five of them 5d, 5e, 5h, 5i and 5j were found to exhibit higher % scavenging potency compared with vitamin C, as the standard. Interesting compound 5i was again the most potent in the series. The current investigation points towards the role of naphthyl group in design of new inhibitors of melanogenesis and the antioxidants with improved efficacy.
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| 8. |
- Zulfiqar, Waqas, et al.
(författare)
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Revisiting the structural, electronic and photocatalytic properties of Ti and Zr based perovskites with meta-GGA functionals of DFT
- 2021
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Ingår i: Journal of Materials Chemistry C. - UK : Royal Society of Chemistry. - 2050-7526 .- 2050-7534. ; 9:14, s. 4862-4876
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Tidskriftsartikel (refereegranskat)abstract
- The strongly constrained and appropriately normed (SCAN) functional of density functional theory (DFT) conforms to all possible exact constraints required of a meta-GGA functional and offers good approximations for structural and energetic properties of solids in comparison to experiments. However, SCAN is unable to fully overcome the underestimation of band gap for perovskite oxide materials suitable for photocatalysis. In the present work, we use a combination of meta-GGAs SCAN and modified Becke–Johnson local density approximation (mBJ-LDA) potential functional to accurately compute the structural, energetic, mechanical, vibrational and optoelectronic properties of Ti and Zr based ABO3 (A = Sr, Ba and B = Ti and Zr) perovskite oxides. In addition to evaluating their physical properties, the potential applications of these materials as photocatalyst operating in the UV region of the electromagnetic spectrum are also examined. We show that the structural, energetic, mechanical and vibrational properties calculated using SCAN are in better agreement with experimental data as compared to the commonly used semi-local functionals of DFT. However, the optoelectronic properties of the large band gap Ti and Zr based perovskite oxides are further improved if computed with the mBJ-LDA potential functional, whereby an even higher level of accuracy than with SCAN is achieved, with results that are comparable to the computationally expensive hybrid DFT functionals. On the whole, our DFT calculations indicate that a combination of SCAN and mBJ-LDA functionals for exploring the physical properties of large band gap perovskite oxides provide the means for identifying photocatalysts suitable for hydrogen production at low computational costs.
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| 9. |
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| 10. |
- Abbas, Nasir, et al.
(författare)
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Untargeted-metabolomics differentiation between poultry samples slaughtered with and without detaching spinal cord
- 2020
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Ingår i: Arabian Journal of Chemistry. - : ELSEVIER. - 1878-5352 .- 1878-5379. ; 13:12, s. 9081-9089
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Tidskriftsartikel (refereegranskat)abstract
- Chicken meat is among the common and relatively inexpensive source of protein consumed worldwide from the poultry industry. Many communities show concern regarding the procedure of slaughtering animals for meat consumption due to ethical, religious, or cultural reasons. Liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) based untargeted metabolomics of 40 chicken meat samples were evaluated to differentiate meat samples based on slaughtering methods. Samples were grouped into, Zabiha (cutting neck without detaching spinal cord) and Non-Zabiha (completely detaching neck). A volcano plot reveals at least 150 features found significantly different between the two groups having >= 2-fold changes in intensities with p-values <= 0.05. Among them 05 identified and 25 unidentified metabolites have clear differences in peak intensities. The identified features can be employed to differentiate meat obtained from different slaughtering methods. A characteristic pattern based on principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA) was observed among the groups. The results will benefit Halal certification, food safety, and security agencies to curb food fraud. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of King Saud University.
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| 11. |
- Afroz, Laila, et al.
(författare)
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Nanocomposite Catalyst (1 – x)NiO-xCuO/yGDC for Biogas Fueled Solid Oxide Fuel Cells
- 2023
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Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 6:21, s. 10918-10928
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Tidskriftsartikel (refereegranskat)abstract
- The composites of Ni–Cu oxides with gadolinium doped ceria (GDC) are emerging as highly proficient anode catalysts, owing to their remarkable performance for solid oxide fuel cells operated with biogas. In this context, the nanocomposite catalysts (1 – x)NiO-xCuO/yGDC (x = 0.2–0.8; y = 1,1.3) are synthesized using a solid-state reaction route. The cubic and monoclinic structures are observed for NiO and CuO phases, respectively, while CeO2 showed cubic fluorite structure. The scanning electron microscopic images revealed a rise in the particle size with an increase in the copper and GDC concentration. The optical band gap values are calculated in the range 2.82–2.33 eV from UV–visible analysis. The Raman spectra confirmed the presence of vibration modes of CeO2 and NiO. The electrical conductivity of the nanocomposite anodes is increased as the concentration of copper and GDC increased and reached at 9.48 S cm–1 for 0.2NiO-0.8CuO/1.3GDC composition at 650 °C. The electrochemical performance of (1 – x)NiO-xCuO/yGDC (x = 0.2–0.8; y = 1,1.3)-based fuel cells is investigated with biogas fuel at 650 °C. Among all of the as-synthesized anodes, the fuel cell with composition 0.2NiO-0.8CuO/1.3GDC showed the best performance, such as an open circuit voltage of 0.84 V and peak power density of 72 mW cm–2. However, from these findings, it can be inferred that among all other compositions, the 0.2NiO-0.8CuO/1.3GDC anode is a superior combination for the high electrochemical performance of solid oxide fuel cells fueled with biogas.
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| 12. |
- El-Seedi, Hesham R., et al.
(författare)
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Honeybee products : An updated review of neurological actions
- 2020
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Ingår i: Trends in Food Science & Technology. - : Elsevier BV. - 0924-2244 .- 1879-3053. ; 101, s. 17-27
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Forskningsöversikt (refereegranskat)abstract
- Background: According to the World Health Organization, two billion people will attain the age of 60 years or more by 2050. Ageing is a major risk factor for a number of neurodegenerative disorders, which currently possess challenge to the global health status, carrying economic and social consequences. Therefore, attention has been dedicated towards the development of neuroprotective agents derived from natural sources. Honeybee products, such as honey, bee pollen, bee bread, propolis, royal jelly, beeswax, and bee venom have been used for therapeutic purposes since ancient times in Egypt, Greece, and China. Despite the emergence of modern medicine, bee products remain clinically relevant owing to their potential as anti-inflammatory, anti-oxidant, and neuroprotective agents.Scope and approach: This review demonstrates the potential of bee products against neurological disorders in the light of the current literature.Key findings and conclusions: Bee products and individual isolated components have enormous therapeutic potential for multiple neurological disorders. The different studies show overall neuroprotective and nerve-tonic characteristics of bee products, mainly due to their anti-oxidant, anti-inflammatory and anti-apoptotic features. However, some limitations such as allergic reactions and the cytotoxic effect of some bee products warrant a special care in its development as drug leads in future studies.
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| 13. |
- Liu, Peijie, et al.
(författare)
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Transport behavior and thermoelectric properties of SnSe/SnS heterostructure modulated with asymmetric strain engineering
- 2022
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Ingår i: Computational materials science. - : Elsevier. - 0927-0256 .- 1879-0801. ; 207
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Tidskriftsartikel (refereegranskat)abstract
- Strain engineering of two-dimensional materials provides specific regulation method for the crystal structure, electric transport behavior and hence thermoelectric properties. Since the layer components of the van der Waals heterojunction exhibit discrepant response to strains, it provides a platform for manipulation of emergent electronic and thermoelectric properties. Here, motivated by the promising thermoelectric materials SnSe and its analogue, we design a specific high-promising thermoelectric candidate based on SnSe-SnS heterostructures, focusing on the strain induced asymmetric bonding-transition and its effect on thermoelectric properties. The compressed SnS/SnSe hetero-bilayer shows significantly enhanced anisotropic electrical transport properties, due to depressed carrier scattering rate along the robust weak bonding direction. In this armchair direction, extremely high power factor values (3600 μW/(cm⋅K2) for n-type and 4000 μW/(cm⋅K2) for p-type) are predicted at ∼1021 cm−3 at 700 K. We obtain a new state-of-the-art thermoelectric material with extremely high thermoelectric power factor and pave the way for strain engineering of thermoelectric van der Waals heterostructures with robust in-plane weak bonding.
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| 14. |
- Lozano, Rafael, et al.
(författare)
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Measuring progress from 1990 to 2017 and projecting attainment to 2030 of the health-related Sustainable Development Goals for 195 countries and territories: a systematic analysis for the Global Burden of Disease Study 2017
- 2018
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Ingår i: The Lancet. - : Elsevier. - 1474-547X .- 0140-6736. ; 392:10159, s. 2091-2138
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Tidskriftsartikel (refereegranskat)abstract
- Background: Efforts to establish the 2015 baseline and monitor early implementation of the UN Sustainable Development Goals (SDGs) highlight both great potential for and threats to improving health by 2030. To fully deliver on the SDG aim of “leaving no one behind”, it is increasingly important to examine the health-related SDGs beyond national-level estimates. As part of the Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017), we measured progress on 41 of 52 health-related SDG indicators and estimated the health-related SDG index for 195 countries and territories for the period 1990–2017, projected indicators to 2030, and analysed global attainment. Methods: We measured progress on 41 health-related SDG indicators from 1990 to 2017, an increase of four indicators since GBD 2016 (new indicators were health worker density, sexual violence by non-intimate partners, population census status, and prevalence of physical and sexual violence [reported separately]). We also improved the measurement of several previously reported indicators. We constructed national-level estimates and, for a subset of health-related SDGs, examined indicator-level differences by sex and Socio-demographic Index (SDI) quintile. We also did subnational assessments of performance for selected countries. To construct the health-related SDG index, we transformed the value for each indicator on a scale of 0–100, with 0 as the 2·5th percentile and 100 as the 97·5th percentile of 1000 draws calculated from 1990 to 2030, and took the geometric mean of the scaled indicators by target. To generate projections through 2030, we used a forecasting framework that drew estimates from the broader GBD study and used weighted averages of indicator-specific and country-specific annualised rates of change from 1990 to 2017 to inform future estimates. We assessed attainment of indicators with defined targets in two ways: first, using mean values projected for 2030, and then using the probability of attainment in 2030 calculated from 1000 draws. We also did a global attainment analysis of the feasibility of attaining SDG targets on the basis of past trends. Using 2015 global averages of indicators with defined SDG targets, we calculated the global annualised rates of change required from 2015 to 2030 to meet these targets, and then identified in what percentiles the required global annualised rates of change fell in the distribution of country-level rates of change from 1990 to 2015. We took the mean of these global percentile values across indicators and applied the past rate of change at this mean global percentile to all health-related SDG indicators, irrespective of target definition, to estimate the equivalent 2030 global average value and percentage change from 2015 to 2030 for each indicator. Findings: The global median health-related SDG index in 2017 was 59·4 (IQR 35·4–67·3), ranging from a low of 11·6 (95% uncertainty interval 9·6–14·0) to a high of 84·9 (83·1–86·7). SDG index values in countries assessed at the subnational level varied substantially, particularly in China and India, although scores in Japan and the UK were more homogeneous. Indicators also varied by SDI quintile and sex, with males having worse outcomes than females for non-communicable disease (NCD) mortality, alcohol use, and smoking, among others. Most countries were projected to have a higher health-related SDG index in 2030 than in 2017, while country-level probabilities of attainment by 2030 varied widely by indicator. Under-5 mortality, neonatal mortality, maternal mortality ratio, and malaria indicators had the most countries with at least 95% probability of target attainment. Other indicators, including NCD mortality and suicide mortality, had no countries projected to meet corresponding SDG targets on the basis of projected mean values for 2030 but showed some probability of attainment by 2030. For some indicators, including child malnutrition, several infectious diseases, and most violence measures, the annualised rates of change required to meet SDG targets far exceeded the pace of progress achieved by any country in the recent past. We found that applying the mean global annualised rate of change to indicators without defined targets would equate to about 19% and 22% reductions in global smoking and alcohol consumption, respectively; a 47% decline in adolescent birth rates; and a more than 85% increase in health worker density per 1000 population by 2030. Interpretation: The GBD study offers a unique, robust platform for monitoring the health-related SDGs across demographic and geographic dimensions. Our findings underscore the importance of increased collection and analysis of disaggregated data and highlight where more deliberate design or targeting of interventions could accelerate progress in attaining the SDGs. Current projections show that many health-related SDG indicators, NCDs, NCD-related risks, and violence-related indicators will require a concerted shift away from what might have driven past gains—curative interventions in the case of NCDs—towards multisectoral, prevention-oriented policy action and investments to achieve SDG aims. Notably, several targets, if they are to be met by 2030, demand a pace of progress that no country has achieved in the recent past. The future is fundamentally uncertain, and no model can fully predict what breakthroughs or events might alter the course of the SDGs. What is clear is that our actions—or inaction—today will ultimately dictate how close the world, collectively, can get to leaving no one behind by 2030.
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| 15. |
- Muhammad, Zahir, et al.
(författare)
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Anisotropic phonon and magnon vibration and gate-tunable optoelectronic properties of nickel thiophosphite
- 2023
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Ingår i: 2D Materials. - : IOP Publishing. - 2053-1583. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- Transition metal phosphorus trichalcogenides retain spin-charge coupling and lattice vibrations in different layers, which are useful for spintronic and optoelectronic devices. The phonon, magnons and excitonic properties of two-dimensional ternary nickel-phosphorus trisulfides (NiPS3) are investigated using Raman spectroscopy and photoluminescence (PL) study. With magnetic exchange interaction, an exotic phonon scattering degenerates the optical phonons into in-plane Ag and Bg modes. We have observed eight Raman modes with two acoustic anisotropic magnon modes (M1, M2) below the critical temperature for co-(XX), while only M1 at cross (XY) polarizations. The M1 mode is coupled with the phonon Bg mode that can survive after transition temperature. The phonon and magnon modes soften with variations in temperature, which is attributed to anharmonic phonon–phonon coupling and interlayer forces. The polarized Raman shows the two-fold and four-fold symmetry orientations of the phonon and magnon modes, respectively, which exhibit strong in-plane anisotropic phonon/magnon. The PL spectra revealed the existence of bound excitonic features and ensemble emitters in NiPS3. The robust interlayer excitation and structural stability further revealed the optothermal properties. Moreover, the fabricated field-effect transistor on NiPS3 reveals p-type semiconducting nature with an ON/OFF ratio of 5 × 106 and mobility of ∼16.34 cm2 V−1 s−1. In contrast, the rectification ratio indicates their diode characteristics. Similarly, the photocurrent is enhanced by changing the wavelength of light, which shows the potential for optoelectronics. The strong spin-charge interaction provides new insights into these materials’ magneto-optical and thermal properties for memory devices.
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| 16. |
- Muhammad, Zahir, et al.
(författare)
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Temperature Modulating Fermi Level Pinning in 2D GeSe for High‐Performance Transistor
- 2022
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Ingår i: Advanced Electronic Materials. - : John Wiley & Sons. - 2199-160X. ; 8:7
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Tidskriftsartikel (refereegranskat)abstract
- 2D layered germanium selenide (GeSe) material possesses in-plane anisotropy because of low-symmetry crystal structure with a new degree of freedom for enhanced optical and electronic properties. However, their systematic vibrational and electronics properties are still under the scope to study. Herein, the vibrational properties of GeSe sheets are studied by Raman spectroscopy. Whereas, the temperature-dependent electronic band structure is studied using angle-resolved photoemission spectroscopy (ARPES) combined with density functional theory calculations. Moreover, the field-effect transistor (FET) is fabricated on a few-layer GeSe with high performance. The vibrational modes (Formula presented.) and (Formula presented.) demonstrates linear softening as the temperature increases, with temperature coefficient value associated by anharmonic phonon–phonon/electron coupling. Besides, the enhanced dielectric screening effect of long-range Coulomb and interlayer interaction is observed from bulk to monolayer. Similarly, ARPES results further show Fermi level movement toward the valance band as increased temperature represents hole doping to pining the Fermi level, which indicates superior carrier concentration for electronic properties. The fabricated FET device on six layers GeSe exhibits high carrier mobility of 52.89 cm2 V−1 s−1 with an on/off ratio above 4 × 105 at room temperature, while it decreased below the room temperature. Our results provide the important figure of merit for GeSe-based novel nanoelectronic and thermoelectric devices.
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| 17. |
- Murray, Christopher J. L., et al.
(författare)
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Population and fertility by age and sex for 195 countries and territories, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017
- 2018
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Ingår i: The Lancet. - 1474-547X .- 0140-6736. ; 392:10159, s. 1995-2051
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Tidskriftsartikel (refereegranskat)abstract
- Background: Population estimates underpin demographic and epidemiological research and are used to track progress on numerous international indicators of health and development. To date, internationally available estimates of population and fertility, although useful, have not been produced with transparent and replicable methods and do not use standardised estimates of mortality. We present single-calendar year and single-year of age estimates of fertility and population by sex with standardised and replicable methods. Methods: We estimated population in 195 locations by single year of age and single calendar year from 1950 to 2017 with standardised and replicable methods. We based the estimates on the demographic balancing equation, with inputs of fertility, mortality, population, and migration data. Fertility data came from 7817 location-years of vital registration data, 429 surveys reporting complete birth histories, and 977 surveys and censuses reporting summary birth histories. We estimated age-specific fertility rates (ASFRs; the annual number of livebirths to women of a specified age group per 1000 women in that age group) by use of spatiotemporal Gaussian process regression and used the ASFRs to estimate total fertility rates (TFRs; the average number of children a woman would bear if she survived through the end of the reproductive age span [age 10–54 years] and experienced at each age a particular set of ASFRs observed in the year of interest). Because of sparse data, fertility at ages 10–14 years and 50–54 years was estimated from data on fertility in women aged 15–19 years and 45–49 years, through use of linear regression. Age-specific mortality data came from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 estimates. Data on population came from 1257 censuses and 761 population registry location-years and were adjusted for underenumeration and age misreporting with standard demographic methods. Migration was estimated with the GBD Bayesian demographic balancing model, after incorporating information about refugee migration into the model prior. Final population estimates used the cohort-component method of population projection, with inputs of fertility, mortality, and migration data. Population uncertainty was estimated by use of out-of-sample predictive validity testing. With these data, we estimated the trends in population by age and sex and in fertility by age between 1950 and 2017 in 195 countries and territories. Findings: From 1950 to 2017, TFRs decreased by 49·4% (95% uncertainty interval [UI] 46·4–52·0). The TFR decreased from 4·7 livebirths (4·5–4·9) to 2·4 livebirths (2·2–2·5), and the ASFR of mothers aged 10–19 years decreased from 37 livebirths (34–40) to 22 livebirths (19–24) per 1000 women. Despite reductions in the TFR, the global population has been increasing by an average of 83·8 million people per year since 1985. The global population increased by 197·2% (193·3–200·8) since 1950, from 2·6 billion (2·5–2·6) to 7·6 billion (7·4–7·9) people in 2017; much of this increase was in the proportion of the global population in south Asia and sub-Saharan Africa. The global annual rate of population growth increased between 1950 and 1964, when it peaked at 2·0%; this rate then remained nearly constant until 1970 and then decreased to 1·1% in 2017. Population growth rates in the southeast Asia, east Asia, and Oceania GBD super-region decreased from 2·5% in 1963 to 0·7% in 2017, whereas in sub-Saharan Africa, population growth rates were almost at the highest reported levels ever in 2017, when they were at 2·7%. The global average age increased from 26·6 years in 1950 to 32·1 years in 2017, and the proportion of the population that is of working age (age 15–64 years) increased from 59·9% to 65·3%. At the national level, the TFR decreased in all countries and territories between 1950 and 2017; in 2017, TFRs ranged from a low of 1·0 livebirths (95% UI 0·9–1·2) in Cyprus to a high of 7·1 livebirths (6·8–7·4) in Niger. The TFR under age 25 years (TFU25; number of livebirths expected by age 25 years for a hypothetical woman who survived the age group and was exposed to current ASFRs) in 2017 ranged from 0·08 livebirths (0·07–0·09) in South Korea to 2·4 livebirths (2·2–2·6) in Niger, and the TFR over age 30 years (TFO30; number of livebirths expected for a hypothetical woman ageing from 30 to 54 years who survived the age group and was exposed to current ASFRs) ranged from a low of 0·3 livebirths (0·3–0·4) in Puerto Rico to a high of 3·1 livebirths (3·0–3·2) in Niger. TFO30 was higher than TFU25 in 145 countries and territories in 2017. 33 countries had a negative population growth rate from 2010 to 2017, most of which were located in central, eastern, and western Europe, whereas population growth rates of more than 2·0% were seen in 33 of 46 countries in sub-Saharan Africa. In 2017, less than 65% of the national population was of working age in 12 of 34 high-income countries, and less than 50% of the national population was of working age in Mali, Chad, and Niger. Interpretation: Population trends create demographic dividends and headwinds (ie, economic benefits and detriments) that affect national economies and determine national planning needs. Although TFRs are decreasing, the global population continues to grow as mortality declines, with diverse patterns at the national level and across age groups. To our knowledge, this is the first study to provide transparent and replicable estimates of population and fertility, which can be used to inform decision making and to monitor progress. Funding: Bill & Melinda Gates Foundation.
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| 18. |
- Naseri, Shabnam, et al.
(författare)
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Realization of either physisorption or chemisorption of 2H-tetraphenylporphyrin on the Cu(111) from density functional theory
- 2024
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Ingår i: Journal of Physics. - : Institute of Physics (IOP). - 0953-8984 .- 1361-648X. ; 36
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption of organic molecules to surfaces is a central issue to achieve fully-functional molecular devices, for which porphyrins are well-studied due to their chemical stability and functional diversity. Herein, we investigate both the physical and the chemical adsorption of the free-base tetraphenylporphyrin 2H-TPP on the Cu(111) surface within the framework of density functional theory and find that the most stable physisorbed configuration is more weakly bound by -0.36 eV than the chemisorbed configuration. We use the electron localization function to investigate the difference in binding mechanisms between strong physisorption and weak chemisorption. We have computed a reaction barrier of 0.12 eV in going from physical binding to chemical bonding to the surface, and a barrier of 50 meV in going between neighboring physical binding sites. Our results support the possibility of realizing free-base porphyrins either physisorbed or chemisorbed on Cu(111) depending on the deposition procedure and experimental conditions.
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| 19. |
- Shah, Shahid, et al.
(författare)
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Assessment of health-related quality of life among patients with obesity, hypertension and type 2 diabetes mellitus and its relationship with multimorbidity
- 2023
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 18:8
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Tidskriftsartikel (refereegranskat)abstract
- Obesity, hypertension (HTN) and type 2 diabetes (T2D) are among the multifactorial disorders that occur at higher prevalence in a population. This study aims to assess the health-related quality of life (HRQoL) of patients with obesity, HTN and T2D individually and in the form of multimorbidity. A questionnaire-based cross-sectional study was conducted among the patients in 15 private clinics of Punjab, Pakistan. A stratified random sampling technique was used to collect the data from patients with obesity, HTN and T2D or their comorbidity. A total of 1350 patients responded by completing the questionnaire. The HRQoL of these patients was assessed using the EQ-5D-5L questionnaire (a standardized instrument for measuring generic health status). Statistical analysis was performed using chi-square test, Mann-Whitney U test, and Kruskal-Wallis test. Multivariate linear regression model was used to model the visual analogue scale (VAS) score. In total, 15% of patients had combined obesity, HTN and T2D; 16.5% had HTN and T2D; 13.5% had obesity and HTN and 12.8% had obesity and T2D. Only 15.8% of patients had obesity, 14.3% had HTN, and 12% had T2D. Mann Whitney-U test gave the statistically significant (p = <0.001) HRQoL VAS score55.1 (±23.2) of patients with the obesity. HRQoL VAS scores of patients with obesity were found to be higher when compared to patients with both T2D 49.8 (±15.4) and HTN 48.2 (±21). Diagnosis of one, two and three diseases showed significant results in VAS with all variables including gender (p = 0.004), educational level (p = <0.001), marital status (p<0.001), residence (p = <0.001), financial situation (p = <0.001) and monthly income (p = <0.001). The most frequently observed extremely problematic dimension was anxiety/ depression (47%) and the self-care (10%) was the least affected. Patient HRQoL is decreased by T2D, HTN, and obesity. The impact of these diseases coexisting is more detrimental to HRQoL.
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| 20. |
- Siddique, Suniya, et al.
(författare)
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Realizing High Thermoelectric Performance in p-Type SnSe Crystals via Convergence of Multiple Electronic Valence Bands
- 2022
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 14:3, s. 4091-4099
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Tidskriftsartikel (refereegranskat)abstract
- SnSe crystals have gained considerable interest for their outstanding thermoelectric performance. Here, we achieve excellent thermoelectric properties in Sn0.99–xPbxZn0.01Se crystals via valence band convergence and point-defect engineering strategies. We demonstrate that Pb and Zn codoping converges the energy offset between multiple valence bands by significantly modifying the band structure, contributing to the enhancement of the Seebeck coefficient. The carrier concentration and electrical conductivity can be optimized, leading to an enhanced power factor. The dual-atom point-defect effect created by the substitution of Pb and Zn in the SnSe lattice introduces strong phonon scattering, significantly reducing the lattice thermal conductivity to as low as 0.284 W m–1 K–1. As a result, a maximum ZT value of 1.9 at 773 K is achieved in Sn0.93Pb0.06Zn0.01Se crystals along the bc-plane direction. This study highlights the crucial role of manipulating multiple electronic valence bands in further improving SnSe thermoelectrics.
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| 21. |
- Sufyan, Ali, et al.
(författare)
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Monolayer TiC—A high-performance Dirac anode with ultralow diffusion barriers and high energy densities for Li-ion and Na-ion batteries
- 2024
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Ingår i: Applied Surface Science. - : Elsevier B.V.. - 0169-4332 .- 1873-5584. ; 642
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional Dirac materials have stimulated substantial research interest as binder-free anodes in metal-ion batteries, owing to their ultrahigh electronic conductivity, large specific area, and higher energy density. Here, using first-principles density functional theory calculations, we have investigated the feasibility of monolayer TiC as a potential anode material for Li/Na-ion batteries. The results indicate that monolayer TiC exhibits excellent dynamical and thermal stability. The electronic structure of monolayer TiC shows semimetallic characteristics with a Dirac cone at the M high symmetry point and the formation of Ti or C vacancies transforms the Dirac cone into a nodal loop or a nodal surface, respectively. Thus, monolayer TiC possesses superior electrical conductivity, which can be further enhanced by the formation of Ti or C vacancies in the material. Furthermore, the calculated adsorption energy values of -0.85 and -0.46 eV for Li-ion and Na-ion, respectively, indicate that Li/Na atom adsorption over monolayer TiC is a favorable process. The density of states plots show that after the adsorption of a single Li/Na atom, monolayer TiC maintains its metallic state, which is advantageous for the diffusion of stored electrons. Most remarkably, monolayer TiC exhibits energy densities of 2684 and 2015 mWh/g for Li and Na, respectively, which are significantly higher than commercial graphite and most other 2D anode materials. The fully loaded TiC anode exhibits excellent cycle stability with volume expansions as low as 0.13 and 0.11%, for Li and Na, respectively. Furthermore, an ultrafast diffusivity with low energy barriers of 0.02 and 0.10 eV is found in monolayer TiC for Li-ion and Na-ion, respectively, which suggests that it has an excellent charge/discharge capability. These exceptional properties make monolayer TiC an excellent candidate as an anode material for Li-ion and Na-ion batteries. Finally, SiC(111) has been proposed as a candidate substrate for monolayer TiC due to its minimal lattice mismatch.
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| 22. |
- Sufyan, Ali, et al.
(författare)
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V4C3 MXene: a Type-II Nodal Line Semimetal with Potential as High-Performing Anode Material for Mg-Ion Battery
- 2024
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Ingår i: ChemSusChem. - : John Wiley & Sons. - 1864-5631 .- 1864-564X. ; 17:7
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Tidskriftsartikel (refereegranskat)abstract
- We have used density functional theory simulations to explore the topological characteristics of a new MXene-like material, V4C3, and its oxide counterpart, assessing their potential as anode materials for Mg-ion batteries. Our research reveals that V4C3 monolayer is a topological type-II nodal line semimetal, protected by time reversal and spatial inversion symmetries. This type-II nodal line is marked by unique drumhead-like edge states that appear either inside or outside the loop circle, contingent upon the edge ending. Intriguingly, even with an increase in metallicity due to oxygen functionalization, the topological features of V4C3 remain intact. Consequently, the monolayer V4C3 has a topologically enhanced electrical conductivity that amplifies further upon oxygen functionalization. During the charging phase, a remarkable storage concentration led to a peak specific capacity of 894.73 mAh g−1 for V4C3, which only decreases to 789.33 mAh g−1 for V4C3O2. When compared to V2C, V4C3 displays a significantly lower specific capacity loss due to functionalization, demonstrating its superior electrochemical properties. Additionally, V4C3 and V4C3O2 exhibit moderate average open-circuit voltages (0.54 V for V4C3 and 0.58 V for V4C3O2) and energy barriers for intercalation migration (ranging between 0.29–0.63 eV), which are desirable for anode materials. Thus, our simulation results support V4C3 potential as an efficient anode material for Mg-ion batteries.
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