| 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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