| 1. |
- Aad, G, et al.
(författare)
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- 2015
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swepub:Mat__t
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| 2. |
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| 3. |
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| 4. |
- Ahuja, B. L., et al.
(författare)
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A study of electron momentum density and charge transfer in W-Cu system
- 2009
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 467:1-2, s. 595-599
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Tidskriftsartikel (refereegranskat)abstract
- We present the first ever Compton scattering study on WxCu1-x(x=0.60, 0.72) alloys. The Compton profile measurements have been made using 20Ci (CS)-C-137 gamma-ray source. The experimental data are compared with the superposition of APW-based Compton profiles of constituent metals. A schematic study on charge transfer has been reported using the experimental valence band Compton profiles of both the alloys, W and Cu. Our first ever data support the charge transfer from W to Cu on alloying, which is also confirmed by our band structure calculations employing exact muffin-tin orbitals method (EMTO). (C) 2007 Elsevier B.V. All rights reserved.
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| 5. |
- Gerkin, RC, et al.
(författare)
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The best COVID-19 predictor is recent smell loss: a cross-sectional study
- 2020
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Ingår i: medRxiv : the preprint server for health sciences. - : Cold Spring Harbor Laboratory.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- BackgroundCOVID-19 has heterogeneous manifestations, though one of the most common symptoms is a sudden loss of smell (anosmia or hyposmia). We investigated whether olfactory loss is a reliable predictor of COVID-19.MethodsThis preregistered, cross-sectional study used a crowdsourced questionnaire in 23 languages to assess symptoms in individuals self-reporting recent respiratory illness. We quantified changes in chemosensory abilities during the course of the respiratory illness using 0-100 visual analog scales (VAS) for participants reporting a positive (C19+; n=4148) or negative (C19-; n=546) COVID-19 laboratory test outcome. Logistic regression models identified singular and cumulative predictors of COVID-19 status and post-COVID-19 olfactory recovery.ResultsBoth C19+ and C19-groups exhibited smell loss, but it was significantly larger in C19+ participants (mean±SD, C19+: -82.5±27.2 points; C19-: -59.8±37.7). Smell loss during illness was the best predictor of COVID-19 in both single and cumulative feature models (ROC AUC=0.72), with additional features providing negligible model improvement. VAS ratings of smell loss were more predictive than binary chemosensory yes/no-questions or other cardinal symptoms, such as fever or cough. Olfactory recovery within 40 days was reported for ∼50% of participants and was best predicted by time since illness onset.ConclusionsAs smell loss is the best predictor of COVID-19, we developed the ODoR-19 tool, a 0-10 scale to screen for recent olfactory loss. Numeric ratings ≤2 indicate high odds of symptomatic COVID-19 (4<OR<10), which can be deployed when viral lab tests are impractical or unavailable.
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| 6. |
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| 7. |
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| 8. |
- Astrath, N. G. C., et al.
(författare)
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Thermal lens and photoacoustic spectroscopy to determine the thermo-optical properties of semiconductors
- 2005
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Ingår i: Journal de Physique IV. - : EDP Sciences. - 1155-4339 .- 1764-7177. ; 125, s. 181-183
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Tidskriftsartikel (refereegranskat)abstract
- In this work we used photoacoustic and thermal lens spectroscopy to study four different semiconductor samples: PbI2, 4HSiC, NiCrO and NiO. The results showed that the combination of these two techniques provided the values of the band gap energies and the thermal diffusivities.
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| 9. |
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| 10. |
- Heathman, S., et al.
(författare)
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A high-pressure structure in curium linked to magnetism
- 2005
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 309:5731, s. 110-113
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Tidskriftsartikel (refereegranskat)abstract
- Curium ties at the center of the actinide series and has a half-filled shell. with seven 5f electrons spatially residing inside its radon core. As a function of pressure, curium exhibits five different crystallographic phases up to 100 gigapascals, of which all but one are also found in the preceding element, americium. We describe here a structure in curium, Cm III, with monoctinic symmetry, space group C2/c, found at intermediate pressures (between 37 and 56 gigapascals). Ab initio electronic structure calculations agree with the observed sequence of structures and establish that it is the spin polarization of curium's 5f electrons that stabilizes Cm Ill. The results reveal that curium is one of a few elements that has a lattice structure stabilized by magnetism.
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| 11. |
- Kong, P. P., et al.
(författare)
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Superconductivity in Strong Spin Orbital Coupling Compound Sb2Se3
- 2014
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 4, s. 6679-
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Tidskriftsartikel (refereegranskat)abstract
- Recently, A(2)B(3) type strong spin orbital coupling compounds such as Bi2Te3, Bi2Se3 and Sb2Te3 were theoretically predicated to be topological insulators and demonstrated through experimental efforts. The counterpart compound Sb2Se3 on the other hand was found to be topological trivial, but further theoretical studies indicated that the pressure might induce Sb2Se3 into a topological nontrivial state. Here, we report on the discovery of superconductivity in Sb2Se3 single crystal induced via pressure. Our experiments indicated that Sb2Se3 became superconductive at high pressures above 10 GPa proceeded by a pressure induced insulator to metal like transition at similar to 3 GPa which should be related to the topological quantum transition. The superconducting transition temperature (T-C) increased to around 8.0 K with pressure up to 40 GPa while it keeps ambient structure. High pressure Raman revealed that new modes appeared around 10 GPa and 20 GPa, respectively, which correspond to occurrence of superconductivity and to the change of T-C slop as the function of high pressure in conjunction with the evolutions of structural parameters at high pressures.
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| 12. |
- Zhu, J., et al.
(författare)
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Superconductivity in Topological Insulator Sb2Te3 Induced by Pressure
- 2013
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 3, s. 2016-
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Tidskriftsartikel (refereegranskat)abstract
- Topological superconductivity is one of most fascinating properties of topological quantum matters that was theoretically proposed and can support Majorana Fermions at the edge state. Superconductivity was previously realized in a Cu-intercalated Bi2Se3 topological compound or a Bi2Te3 topological compound at high pressure. Here we report the discovery of superconductivity in the topological compound Sb2Te3 when pressure was applied. The crystal structure analysis results reveal that superconductivity at a low-pressure range occurs at the ambient phase. The Hall coefficient measurements indicate the change of p-type carriers at a low-pressure range within the ambient phase, into n-type at higher pressures, showing intimate relation to superconducting transition temperature. The first principle calculations based on experimental measurements of the crystal lattice show that Sb2Te3 retains its Dirac surface states within the low-pressure ambient phase where superconductivity was observed, which indicates a strong relationship between superconductivity and topology nature.
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| 13. |
- Abdel-Hafiez, Mahmoud, et al.
(författare)
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Pressure-induced reentrant transition in NbS3 phases : Combined Raman scattering and x-ray diffraction study
- 2019
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Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 99:23
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Tidskriftsartikel (refereegranskat)abstract
- We report the evolution of charge density wave states under pressure for two NbS3 phases: triclinic (phase I) and monoclinic (phase II) at room temperature. Raman and x-ray diffraction (XRD) techniques are applied. The x-ray studies on the monoclinic phase under pressure show a compression of the lattice at different rates below and above similar to 7 GPa but without a change in space group symmetry. The Raman spectra of the two phases evolve similarly with pressure; all peaks almost disappear in the similar to 6-8 GPa range, indicating a transition from an insulating to a metallic state, and peaks at new positions appear above 8 GPa. The results suggest suppression of the ambient charge-density waves and their subsequent recovery with new orderings above 8 GPa.
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| 14. |
- Ahuja, SK, et al.
(författare)
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A plea for justice for jailed medical workers
- 2006
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Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 314:5801, s. 924-925
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 15. |
- Arslanov, T. R., et al.
(författare)
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Low energy band gap state in compressed needlelike structure of CdSb:Ni
- 2019
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 115:25
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Tidskriftsartikel (refereegranskat)abstract
- We studied the effect of high pressure on the border of intrinsic conductivity in CdSb doped with 0.5%Ni, the structure of which is needlelike due to spherical extended NiSb inclusions. The bandgap state has been found to be strongly governed by a structural transition in the composite structure. A pressure-induced phase exhibits an activation behavior only upon heating with a very low energy gap by 0.05 eV at 5.32 GPa, while metallic conductivity appears upon subsequent cooling, which is attributed to the instability of the cadmium antimonide structure. Room-temperature Hall effect measurements confirm that the high-pressure phase is not fully metallized, yielding a hole concentration of 4.08 x 10(18) cm(-3) at the onset of structural transition and a reduced magnitude by order in this phase.
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| 16. |
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| 17. |
- Banerjee, Paramita, et al.
(författare)
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First principles design of Li functionalized hydrogenated h-BN nanosheet for hydrogen storage
- 2016
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 41:32, s. 14437-14446
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Tidskriftsartikel (refereegranskat)abstract
- Employing first principles density functional theory (DFT) based approach, the structure, stability and hydrogen storage efficiency of a hydrogenated hexagonal boron nitride sheet (BHNH chair conformer) functionalized by the lightest alkali metal atom Li has been explored here in details. Substituting one hydrogen atom from both B and N sides of BHNH sheet by a Li atom, we have found that Li becomes cationic and acts as a binding site to adsorb hydrogen molecules. The stability of this Li-substituted BHNH sheet has been indicated via Ab-initio Molecular Dynamics (AIMD) simulation upto 400 K. The binding energy (similar to 0.18-0.3 eV/H-2 molecule) and gravimetric density (similar to 6 wt %) (upto similar to 200 K) of the hydrogen molecules fall in the required window for practical hydrogen storage. AIMD simulation indicates complete dehydrogenation from this system occurs at similar to 400 K, thereby predicting the suitability of this system from the point of view of efficient hydrogen storage.
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| 18. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 19. |
- Belonoshko, Anatoly B., et al.
(författare)
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Molecular dynamics simulation of the structure of yttria Y2O3 phases using pairwise interactions
- 2001
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 6418:18
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the structure of yttria (Y2O3) by means of ab initio and molecular dynamics methods. The suggested simple model for the interatomic interaction is shown to produce reasonable results at moderate pressures for a wide range of temperatures. The calculated x-ray structure factor is in good agreement with experimental data obtained by the x-ray levitation technique at the temperature of 2526 K. The quality of the agreement decreases with increasing temperature. We demonstrate that it is not necessary to assume nonstoichiometry of liquid yttria, as was done in a recent publication, to obtain agreement with experiment. The structure of liquid yttria can be considered as a mixture of 4- and 6-coordinated Y atoms. We also show the possibility of a light amorphous yttria phase, which possibly can be obtained by quenching from a vapor instead of conventional amorphous yttria quenched from a liquid.
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| 20. |
- Berseth, P. A., et al.
(författare)
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Carbon Nanomaterials as Catalysts for Hydrogen Uptake and Release in NaAlH4
- 2009
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Ingår i: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 9:4, s. 1501-1505
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Tidskriftsartikel (refereegranskat)abstract
- A synergistic approach involving experiment and first-principles theory not only shows that carbon nanostructures can be used as catalysts for hydrogen uptake and release in complex metal hydrides such as sodium alanate, NaAlH4, but also provides an unambiguous understanding of how the catalysts work. Here we show that the stability of NaAlH4 originates with the charge transfer from Na to the AlH4 moiety, resulting in an ionic bond between Na+ and AlH4- and a covalent bond between Al and H. Interaction of NaAlH4 with an electronegative substrate such as carbon fullerene or nanotube affects the ability of Na to donate its charge to AlH4, consequently weakening the Al-H bond and causing hydrogen to desorb at lower temperatures as well as facilitating the absorption of H-2 to reverse the dehydrogenation reaction. In addition, based on our experimental observations and theoretical calculations it appears the curvature of the carbon nanostructure plays a role in the catalytic process. Ab initio molecular dynamics simulation further reveals the time evolution of the charge transfer process.
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| 21. |
- Broadaway, K Alaine, et al.
(författare)
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Loci for insulin processing and secretion provide insight into type 2 diabetes risk.
- 2023
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Ingår i: American Journal of Human Genetics. - : Elsevier. - 0002-9297 .- 1537-6605. ; 110:2, s. 284-299
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Tidskriftsartikel (refereegranskat)abstract
- Insulin secretion is critical for glucose homeostasis, and increased levels of the precursor proinsulin relative to insulin indicate pancreatic islet beta-cell stress and insufficient insulin secretory capacity in the setting of insulin resistance. We conducted meta-analyses of genome-wide association results for fasting proinsulin from 16 European-ancestry studies in 45,861 individuals. We found 36 independent signals at 30 loci (p value < 5 × 10-8), which validated 12 previously reported loci for proinsulin and ten additional loci previously identified for another glycemic trait. Half of the alleles associated with higher proinsulin showed higher rather than lower effects on glucose levels, corresponding to different mechanisms. Proinsulin loci included genes that affect prohormone convertases, beta-cell dysfunction, vesicle trafficking, beta-cell transcriptional regulation, and lysosomes/autophagy processes. We colocalized 11 proinsulin signals with islet expression quantitative trait locus (eQTL) data, suggesting candidate genes, including ARSG, WIPI1, SLC7A14, and SIX3. The NKX6-3/ANK1 proinsulin signal colocalized with a T2D signal and an adipose ANK1 eQTL signal but not the islet NKX6-3 eQTL. Signals were enriched for islet enhancers, and we showed a plausible islet regulatory mechanism for the lead signal in the MADD locus. These results show how detailed genetic studies of an intermediate phenotype can elucidate mechanisms that may predispose one to disease.
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| 22. |
- Caron, Bénédicte, et al.
(författare)
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IOIBD Recommendations for Clinical Trials in Ulcerative Proctitis : the PROCTRIAL Consensus
- 2022
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Ingår i: Clinical Gastroenterology and Hepatology. - : Elsevier. - 1542-3565 .- 1542-7714. ; 20:11, s. 2169-2627.e1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND AIMS: Clinical trials evaluating biologics and small molecules in patients with ulcerative colitis are predominantly excluding ulcerative proctitis. The objective of the PROCTRIAL (Definition and endpoints for ulcerative PROCtitis in clinical TRIALs) initiative was to develop consensus statements for definitions, inclusion criteria, and endpoints for the evaluation of ulcerative proctitis in adults.METHODS: Thirty-five international experts held a consensus meeting to define ulcerative proctitis, and the endpoints to use in clinical trials. Based on a systematic review of the literature, statements were generated, discussed, and approved by the working group participants using a modified Delphi method. Consensus was defined as at least 75% agreement among voters.RESULTS: The group agreed that the diagnosis of ulcerative proctitis should be made by ileocolonoscopy and confirmed by histopathology, with the exclusion of infections, drug-induced causes, radiation, trauma, and Crohn's disease. Ulcerative proctitis was defined as macroscopic extent of lesions limited to 15 cm distance from the anal verge in adults. Primary and secondary endpoints were identified to capture response of ulcerative proctitis to therapy. A combined clinical and endoscopic primary endpoint for the evaluation of ulcerative proctitis disease activity is proposed. Secondary endpoints which should be evaluated include endoscopic remission, histological remission, mucosal healing, histologic endoscopic mucosal improvement, disability, fecal incontinence, urgency, constipation, and health-related quality of life.CONCLUSION: In response to the need for guidance on the design of clinical trials in patients with ulcerative proctitis, the PROCTRIAL consensus provides recommendations on the definition and endpoints for ulcerative proctitis clinical trials.
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| 23. |
- Chakraborty, Sudip, et al.
(författare)
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Rational Design : A High-Throughput Computational Screening and Experimental Validation Methodology for Lead-Free and Emergent Hybrid Perovskites
- 2017
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Ingår i: ACS Energy Letters. - : American Chemical Society (ACS). - 2380-8195. ; 2:4, s. 837-845
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Tidskriftsartikel (refereegranskat)abstract
- Perovskite solar cells, with efficiencies of 22.1%, are the only solution-processable technology to outperform multicrystalline silicon and thin-film solar cells. Whereas substantial progress has been made in scalability and stability, toxicity concerns drive the need for lead replacement, intensifying research into the broad palette of elemental substitutions, solid solutions, and multidimensional structures. Perovskites have gone from comprising three to more than eight (CH3NH3, HC(NH2)(2), Cs, Rb, Pb, Sn, I, Br) organic and inorganic constituents, and a variety of new embodiments including layered, double perovskites, and metal-deficient perovskites are being explored. Although most experimentation is guided by intuition and trial-and-error-based Edisonian approaches, rational strategies underpinned by computational screening and targeted experimental validation are emerging. In addressing emergent perovskites, this perspective discusses the rational design methodology leveraging density functional theory-based high-throughput computational screening coupled to downselection strategies to accelerate the discovery of materials and industrialization of perovskite solar cells.
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| 24. |
- da Rocha, V. N., et al.
(författare)
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Electronic, mechanical, and optical properties of BP nanotubes : A first-principles study
- 2023
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Ingår i: COMPUTATIONAL CONDENSED MATTER. - : Elsevier. - 2352-2143. ; 34
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Tidskriftsartikel (refereegranskat)abstract
- The electronic, mechanical, and optical properties of (3,3), (5,5), (7,7) and (9,9) armchair and (4,0), (6,0), (8,0), (10,0) and (12,0) zigzag boron phosphide nanotubes (BPNT's) have been investigated using density functional theory calculations. We find that, with the exception of the (5,5) nanotube, they are direct band gap semiconductors, as the BP monolayer. The (3,3) and (4,0) nanotubes are verified to be unstable through phonon band structure calculations. The 1D stretching moduli and elastic moduli show that the BP NT's are as stiff as carbon nanotubes of comparable diameters. The absorption spectra of the BP nanotubes have thresholds in the visible region, differently from carbon and boron nitride nanotubes of comparable dimensions.
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| 25. |
- Dallera, C., et al.
(författare)
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Understanding mixed valent materials : Effects of dynamical core-hole screening in high-pressure x-ray spectroscopy
- 2006
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 74:8, s. 081101-
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Tidskriftsartikel (refereegranskat)abstract
- Changes in the electronic structure of Yb, a material whose valence is modified under pressure, are observed with remarkable detail in x-ray absorption and emission data measured between ambient conditions and 20 GPa. These changes are reproduced by a theory that essentially does not rely on experimental parameters, and includes dynamical core-hole screening. From the combined experimental and theoretical data we can firmly establish on a quantitative level how the valency of an intermediate valence material is modified by pressure. In metallic Yb it increases from 2 to 2.55 +/- 0.05 between 0 and 20 GPa.
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| 26. |
- Das, T., et al.
(författare)
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Charge transfer driven interaction of CH4, CO2 and NH3 with TiS2 monolayer : Influence of vacancy defect
- 2021
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Ingår i: Catalysis Today. - : Elsevier B.V.. - 0920-5861 .- 1873-4308. ; 370, s. 189-195
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Tidskriftsartikel (refereegranskat)abstract
- In this work we have investigated the dissociation of hydrogen rich CH4 and NH3 molecules along with CO2 on the surface of pristine and various defect induced TiS2 monolayer. The aim is to see whether the monolayer surfaces are able to produce H2 by decomposing the feedstock adsorbates and also to examine whether it can be a sorbent for CO2. We have tried to explore a monolayer surface which can simultaneously act as a catalyst to dissociate CH4, as well as to adsorb CO2 which is the only harmful by-product in steam reforming method for hydrogen production from CH4. The hydrogen generation has been predicted from the nature of gas adsorption, and the adsorption energies have been estimated to see whether it falls under chemisorption or physisorption range. Both S and Ti vacancy defects have been studied and the first-principles electronic structure calculation helps to envisage the charge redistribution of the three adsorbates on both pristine and defective TiS2 surfaces.
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| 27. |
- Dong, C. L., et al.
(författare)
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Electronic structure and surface structure of Cu2S nanorods from polarization dependent X-ray absorption spectroscopy
- 2006
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Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - : Elsevier BV. - 0368-2048 .- 1873-2526. ; 151:1, s. 64-70
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Tidskriftsartikel (refereegranskat)abstract
- Highly aligned CuS nanorods have been studied by polarization dependent X-ray absorption spectroscopy. In contrast to bulk Cu2S, strong s, p, and d hybridization is found in the nanorods. The polarization dependence shows a predominant d(z2) character of Cu 3d states. Ab initio multiple-scattering calculations confirm the strong hybridization, and reveal that CuS nanorods are grown along the z-axis of chalcocite structure with Cu-7 and Cu-10 sites being the main building blocks. The hybridized absorption peak in the nanorods is shifted towards lower energies for smaller diameter of nanorods, which is attributed to surface reconstruction due to strong Cu-Cu interactions on the Cu-rich surface of the nanorods.
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| 28. |
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| 29. |
- Dubrovinskaia, N., et al.
(författare)
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Beating the miscibility barrier between iron group elements and magnesium by high-pressure alloying
- 2005
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 95:24
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Tidskriftsartikel (refereegranskat)abstract
- Iron and magnesium are almost immiscible at ambient pressure. The low solubility of Mg in Fe is due to a very large size mismatch between the alloy components. However, the compressibility of Mg is much higher than that of Fe, and therefore the difference in atomic sizes between elements decreases dramatically with pressure. Based on the predictions of ab initio calculations, we demonstrate in a series of experiments in a multianvil apparatus and in electrically and laser-heated diamond anvil cells that high pressure promotes solubility of magnesium in iron. At the megabar pressure range, more than 10 at. % of Mg can dissolve in Fe and then the alloy can be quenched to ambient conditions. A generality of the concept of high-pressure alloying between immiscible elements is demonstrated by its application to two other Fe group elements, Co and Ni.
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| 30. |
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| 31. |
- Dwibedi, Debasmita, et al.
(författare)
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Na2.44Mn1.79(SO4)(3) : a new member of the alluaudite family of insertion compounds for sodium ion batteries
- 2015
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 3:36, s. 18564-18571
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Tidskriftsartikel (refereegranskat)abstract
- Sodium-ion batteries have been extensively pursued as economic alternatives to lithium-ion batteries. Investigating the polyanion chemistry, alluaudite structured Na2Fe2II(SO4)(3) has been recently discovered as a 3.8 V positive electrode material (Barpanda et al., Nature Commun., 5: 4358, 2014). Registering the highest ever Fe-III/Fe-II redox potential (vs. Na/Na+) and formidable energy density, it has opened up a new polyanion family for sodium batteries. Exploring the alluaudite family, here we report isotypical Na2+2xMn2-xII(SO4)(3) (x = 0.22) as a novel high-voltage cathode material for the first time. Following low-temperature (ca. 350 degrees C) solid-state synthesis, the structure of this new alluaudite compound has been solved adopting a monoclinic framework (s.g. C2/c) showing antiferromagnetic ordering at 3.4 K. Synergising experimental and ab initio DFT investigation, Na2+2xMn2-xII(SO4)(3) has been found to be a potential high-voltage (ca. 4.4 V) cathode material for sodium batteries.
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| 32. |
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| 33. |
- Frank, Stefan, et al.
(författare)
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yylncT Defines a Class of Divergently Transcribed lncRNAs and Safeguards the T-mediated Mesodermal Commitment of Human PSCs.
- 2019
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Ingår i: Cell stem cell. - : Elsevier BV. - 1875-9777 .- 1934-5909. ; 24:2
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Tidskriftsartikel (refereegranskat)abstract
- Human protein-coding genes are often accompanied by divergently transcribed non-coding RNAs whose functions, especially in cell fate decisions, are poorly understood. Using an hESC-based cardiac differentiation model, we define a class of divergent lncRNAs, termed yin yang lncRNAs (yylncRNAs), that mirror the cell-type-specific expression pattern of their protein-coding counterparts. yylncRNAs arepreferentially encoded from the genomic loci ofkey developmental cell fate regulators. Most yylncRNAs are spliced polyadenylated transcripts showing comparable expression patterns invivo inmouse and in human embryos. Signifying theirdevelopmental function, the key mesoderm specifier BRACHYURY (T) is accompanied by yylncT, whichlocalizes to the active T locus during mesoderm commitment. yylncT binds the de novo DNA methyltransferase DNMT3B, and its transcript is required for activation of the T locus, with yylncTdepletion specifically abolishing mesodermal commitment. Collectively, we report a lncRNA-mediated regulatory layer safeguarding embryonic cell fate transitions.
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| 34. |
- G.E. Grechnev,, et al.
(författare)
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Electronic structure and magnetic properties of Lithium manganese spinels
- 2003
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Ingår i: J.Magn. Magn. Matt.. ; 258, s. 287-289
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Tidskriftsartikel (refereegranskat)abstract
- Electronic and magnetic structures of the spinel-type lithium–manganese oxides LixMn2O4, x=0,0.5,1, are studied ab initio by employing a full-potential LMTO method. The effect of the orthorhombic distortion on electronic structure and magnetism of LiMn2O4 was investigated, and our calculations do not show a substantial charge ordering at the structural transition from the cubic spinel to the orthorhombic structure.
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| 35. |
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| 36. |
- Gerislioglu, B., et al.
(författare)
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The role of Ge2Sb2Te5 in enhancing the performance of functional plasmonic devices
- 2020
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Ingår i: Materials Today Physics. - : Elsevier. - 2542-5293. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Phase-change materials (PCMs) and compounds enable a combination of features for implementing advanced and multifunctional nanophotonic applications. Possessing opposite phases at different temperatures and toggling between amorphous to crystalline states (set-reset states) lead to dramatic changes in the optical characteristics of them. In this review, we focus on the recent progresses in the field of multifunctional nanoplasmonics based on integrated PCMs. More precisely, we explain the use of a well-known phase-change compound, Ge2Sb2Te5 (GST), in tailoring efficient and tunable plasmonic devices. Formed by the chalcogenide family and as a notable member of PCM components, GST has received a growing attention in the past years for developing non-volatile random access memory technology and optical systems. The reconfigurable and non-volatile characteristics of GST allow for the manipulation of light in subwavelength geometries. Based on the knowledge in the field of functional nanophotonic devices, we demonstrate promising paths that have been introduced to improve the efficiency of optical devices based on the PCM technology. Furthermore, we discuss the unique properties of GST in designing of modern plasmonic and nanophotonic tools. Finally, we present an outlook for the future opportunities of GST-mediated nanoplatforms, including all-optical instruments, beam-steering metasurfaces, and nanoscale switches and absorbers.
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| 37. |
- Gerkin, Richard C., et al.
(författare)
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Recent Smell Loss Is the Best Predictor of COVID-19 Among Individuals With Recent Respiratory Symptoms
- 2021
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 46
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Tidskriftsartikel (refereegranskat)abstract
- In a preregistered, cross-sectional study, we investigated whether olfactory loss is a reliable predictor of COVID-19 using a crowdsourced questionnaire in 23 languages to assess symptoms in individuals self-reporting recent respiratory illness. We quantified changes in chemosensory abilities during the course of the respiratory illness using 0–100 visual analog scales (VAS) for participants reporting a positive (C19+; n = 4148) or negative (C19−; n = 546) COVID-19 laboratory test outcome. Logistic regression models identified univariate and multivariate predictors of COVID-19 status and post-COVID-19 olfactory recovery. Both C19+ and C19− groups exhibited smell loss, but it was significantly larger in C19+ participants (mean ± SD, C19+: −82.5 ± 27.2 points; C19−: −59.8 ± 37.7). Smell loss during illness was the best predictor of COVID-19 in both univariate and multivariate models (ROC AUC = 0.72). Additional variables provide negligible model improvement. VAS ratings of smell loss were more predictive than binary chemosensory yes/no-questions or other cardinal symptoms (e.g., fever). Olfactory recovery within 40 days of respiratory symptom onset was reported for ~50% of participants and was best predicted by time since respiratory symptom onset. We find that quantified smell loss is the best predictor of COVID-19 amongst those with symptoms of respiratory illness. To aid clinicians and contact tracers in identifying individuals with a high likelihood of having COVID-19, we propose a novel 0–10 scale to screen for recent olfactory loss, the ODoR-19. We find that numeric ratings ≤2 indicate high odds of symptomatic COVID-19 (4 < OR < 10). Once independently validated, this tool could be deployed when viral lab tests are impractical or unavailable.
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| 38. |
- Ghosh, Anirudha, et al.
(författare)
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Exotic magnetic and electronic properties of layered CrI3 single crystals under high pressure
- 2022
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 105:8
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Tidskriftsartikel (refereegranskat)abstract
- Through advanced experimental techniques on CrI3 single crystals, we derive a pressure-temperature phase diagram. We find that T-c increases to similar to 66 K with pressure up to similar to 3 GPa followed by a decrease to similar to 10 K at 21.2 GPa. The experimental results are reproduced by theoretical calculations based on density functional theory where electron-electron interactions are treated by a static on-site Hubbard U on Cr 3d orbitals. The origin of the pressure-induced reduction of the ordering temperature is associated with a decrease in the calculated bond angle, from 95 degrees at ambient pressure to similar to 85 degrees at 25 GPa. Above 22 GPa, experiment and theory jointly point to the idea that the ferromagnetically ordered state is destroyed, giving rise first to a complex, unknown magnetic configuration, and at sufficiently high pressures a pure antiferromagnetic configuration. This sequence of transitions in the magnetism is accompanied by a well-detected pressure-induced semiconductor-to-metal phase transition that is revealed by both high-pressure resistivity measurements and ab initio theory.
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| 39. |
- Grechnev, G. E., et al.
(författare)
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Electronic structure, magnetic, and cohesive properties of LixMn2O4 : Theory
- 2002
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 65:17
-
Tidskriftsartikel (refereegranskat)abstract
- The volume dependent electronic structure of the spinel-type lithium manganese oxides LixMn2O4, x=0,0.5,1, is studied ab initio by employing a full-potential electronic structure method. The electronic structure, total energies, open-circuit voltage, and magnetic moments were obtained for various spin configurations of LixMn2O4 in the cubic spinel structure and the low-temperature orthorhombic structure. The effect of magnetic ordering on the band structure and structural stability has been investigated and an antiferromagnetic ordering proved to be the ground state of the LixMn2O4 spinels. Our calculations show that the manganese majority t(2g) d band is filled for all LixMn2O4 compounds studied, and the filling of the minority t(2g) band is expected in the lithiation process. The lithium intercalation potential, bulk modulus, magnetic moments, and optical properties are calculated within the itinerant band approach and are found to be in good agreement with available experimental data, indicating, that the density-functional theory provides reliable electronic structure of the LixMn2O4 system. The effect of the orthorhombic distortion on electronic structure and magnetism of LiMn2O4 was investigated, and our calculations do not show a substantial charge ordering at the structural transition from the cubic spinel to the orthorhombic structure, as proposed earlier. Instead, the low-temperature orthorhombic structure is found to possess the lowest energy via a Jahn-Teller distortion driven by the d band.
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| 40. |
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| 41. |
- Grechnev, G. E., et al.
(författare)
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Magnetic susceptibility of hcp iron and the seismic anisotropy of Earth's inner core
- 2003
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Ingår i: PHYSICAL REVIEW B. - 1098-0121. ; 68:6, s. 064414-
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Tidskriftsartikel (refereegranskat)abstract
- The seismic anisotropy of the Earth's core is believed to be due to a preferred orientation of hexagonal close packed (hcp) iron crystals that constitute the dominating element in the inner core. In this connection, the magnetic properties of the hcp iron in an external magnetic field are very interesting and are studied here by employing an ab initio full-potential linear muffin tin orbital method. By this means the magnetic susceptibility chi of hcp iron and its anisotropy energy for pressures and temperatures corresponding to the Earth's inner core conditions have been evaluated in the framework of the local spin density approximation. The accuracy of this method has been validated by calculating the anisotropic susceptibility of paramagnetic transition metals that form in the hcp crystal structure at ambient conditions. Our calculations demonstrate that for hcp iron the anisotropy of chi is dependent on the c/a ratio. In conjunction with recent data on the c/a ratio and elastic constants of hcp iron, the magnetic anisotropy can explain the seismic anisotropy of the Earth's inner core.
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| 42. |
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| 43. |
- Gupta, Divyani, et al.
(författare)
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Local electrocatalytic activity of PtRu supported on nitrogen-doped carbon nanotubes towards methanol oxidation by scanning electrochemical microscopy
- 2021
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 9:37, s. 21291-21301
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Tidskriftsartikel (refereegranskat)abstract
- Nitrogen-doped carbon nanotubes (NCNTs) were synthesized by treating HNO3-oxidized carbon nanotubes (CNTs) in an NH3 flow at different temperatures. PtRu nanoparticles were decorated over NCNTs. The PtRu catalysts were prepared by an impregnation-reduction method from metal chloride precursors with a total metal loading of about 10 wt%. The electrocatalytic activity with respect to methanol oxidation was studied using electrochemical and scanning electrochemical microscopy (SECM) measurements. Transmission electron microscopy revealed the spherical shape and narrow particle size distribution of the PtRu particles over NCNTs with average particle sizes of similar to 3-5 nm. A detailed X-ray photoelectron spectroscopy study was performed to quantitatively identify different nitrogen functional groups and to evaluate their role in the observed enhanced catalytic activity towards methanol oxidation. The determination of the local electrocatalytic activity of the proposed catalyst towards methanol oxidation and simultaneous evaluation of the intermediates produced during methanol oxidation were achieved using SECM. Density functional theory studies were performed to understand the adsorption sites of methanol and intermediates on different reactive sites and to investigate possible reaction mechanisms.
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| 44. |
- Gutierrez, G., et al.
(författare)
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Structural properties of liquid Al2O3 : A molecular dynamics study
- 2000
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Ingår i: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics. - 1063-651X .- 1095-3787. ; 61:3, s. 2723-2729
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Tidskriftsartikel (refereegranskat)abstract
- Molecular dynamics (MD) simulations of liquid aluminum oxide (Al2O3) were carried out on a system with up to 1800 particles, using a pairwise potential. All simulations were done in the microcanonical ensemble, for two densities, 3.0 and 3.175 g/cm(3), at temperatures of 2200, 2600, and 3000 K. A detailed analysis of the interatomic distances, given by the partial pair-distribution functions and the bond-angles distribution, reveals that in the liquid state there is st short range order dominated by a somewhat distorted (AlO4)(5-) tetrahedron, in agreement with recent experimental measurements. This conclusion is supported by the distribution of nearest-neighbor coordinations, where more than 60% of Al atoms have four O as nearest neighbors. This finding does not change over the explored temperature range. Because of the presence of twofold rings, the connectivity of (AlO4)(5-) units consists of corner, edge, and face sharing tetrahedra. Based in this structural information, i.e., bond lengths, coordination numbers, bond-angle distributions, and ring statistics, our MD simulation allows us to put forward a possible structure of liquid Al2O3.
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| 45. |
- Gutierrez, G, et al.
(författare)
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Structural properties of liquid Al2O3: A molecular dynamics study
- 2000
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Ingår i: PHYSICAL REVIEW E. - : AMERICAN PHYSICAL SOC. - 1063-651X. ; 61:3, s. 2723-2729
-
Tidskriftsartikel (refereegranskat)abstract
- Molecular dynamics (MD) simulations of liquid aluminum oxide (Al2O3) were carried out on a system with up to 1800 particles, using a pairwise potential. All simulations were done in the microcanonical ensemble, for two densities, 3.0 and 3.175 g/cm(3), at
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| 46. |
- Heathman, S., et al.
(författare)
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The unique high-pressure behavior of curiurn probed further using alloys
- 2007
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 444, s. 138-141
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Tidskriftsartikel (refereegranskat)abstract
- The changing role of the 5f electrons across the actinide series has been of prime interest for many years. The remarkable behavior of americium's 5f electrons under pressure was determined experimentally a few years ago and it precipitated a strong interest in the heavy element community. Theoretical treatments of americium's behavior under pressure followed and continue today. Experimental and theoretical findings regarding curium's behavior under pressure have shown that the pressure behavior of curium was not a mirror image of that for americium. Rather, one of the five crystallographic phases observed with curium (versus four for americium) was a unique monoclinic structure whose existence is due to a spin stabilization effect by curium's 5f(7) electronic configuration and its half-filled 5f-shell. We review briefly the behavior of pure curium under pressure but focus on the pressure behaviors of three curium alloys with the intent of comparing them with pure curium. An important experimental finding confirmed by theoretical computations, is that dilution of curium with its near neighbors is sufficient to prevent the formation of the unique C2/c phase that appears in pure Cm metal under pressure. As this unique C2/c phase is very sensitive to having a 5f7 configuration to maximize the magnetic spin polarization, dilution of this state with adjacent actinide neighbors reduces its stability.
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| 47. |
- Hjorvarsson, B, et al.
(författare)
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Probing the local electronic structure in the H induced metal-insulator transition of Y
- 1999
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Ingår i: JOURNAL OF PHYSICS-CONDENSED MATTER. ; 11, s. L119-
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Tidskriftsartikel (refereegranskat)abstract
- The occupied acid unoccupied valence band states of yttrium (Y) metal, Y dihydride and Y trihydride were measured by soft x-ray emission and absorption spectroscopy. The experiments were complemented by first principles calculations. Both experiments and
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| 48. |
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| 49. |
- Hugosson, Håkan Wilhelm, et al.
(författare)
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Stabilization of potential superhard RuO2 phases : A theoretical study
- 2002
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 66:17
-
Tidskriftsartikel (refereegranskat)abstract
- First-principles full-potential linear muffin-tin orbital calculations have been used to study RuO2 in the fluorite (CaF2) and rutile structures. An investigation of the effects of metal and nonmetal alloying, oxygen vacancies, and lattice strain on the phase stabilities and electronic structure has been made. From these theoretical results suggestions on how the cubic phase may be stabilized are made. The pressure induced phase transitions between the rutile, CaCl2, Pa3 and fluorite phases and the bulk moduli of several 4d and 5d transition metal dioxides have also been studied.
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| 50. |
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