| 1. |
- Alluri, Nagamalleswara Rao, et al.
(författare)
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Crystallinity modulation originates ferroelectricity like nature in piezoelectric selenium
- 2022
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Ingår i: Nano Energy. - : Elsevier. - 2211-2855 .- 2211-3282. ; 95
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Tidskriftsartikel (refereegranskat)abstract
- Modern room temperature ferroelectrics/piezoelectrics significantly impact advanced nanoelectronics than conventional chemical compounds. Changes in crystallinity modulation, long-range order of atoms in metalloids permits the design of novel materials. The ferroelectric like nature of a single element (selenium, Se) is demonstrated via in-plane (E perpendicular to(ar) to the Se helical chains in micro-rod (MR)) and out-of-plane (E parallel to(el) to the Se helical chains in MR) polarization. Atomic electron microscopy shows large stacks of covalently bound Se atoms in a c-axis orientation for tip bias voltage-dependent switchable domains with a 180 degrees phase and butterfly displacement curves. The single crystalline Se MR has a high in-plane piezoelectric coefficient of 30 pm/V relative to polycrystalline samples due to larger grains, crystal imperfections in MR, and tuned helical chains. The energy conversion of a single Se-MR demonstrated via d(13), d(12) (or d(15)) piezoelectric modes.
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| 2. |
- 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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| 3. |
- Gaurav, Kumar, et al.
(författare)
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Trans-polyacetylene based organic spin valve for a multifunctional spin-based device : A first principle analysis
- 2022
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Ingår i: JOURNAL OF SCIENCE-ADVANCED MATERIALS AND DEVICES. - : Elsevier. - 2468-2284 .- 2468-2179. ; 7:3
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Tidskriftsartikel (refereegranskat)abstract
- Carbon-based materials are the promising candidates for the design of multifunctional spintronic devices, owing to their fascinating inherent attributes such as the ballistic transport nature, long spin coherence time, etc. Here, we report the spin-dependent electron transport properties of a transpolyacetylene channel sandwiched between two semi-infinite hydrogen-passivated zigzag graphene nanoribbon (ZGNR) electrodes within the framework of spin-polarized density functional theory (DFT) and non-equilibrium Green's function (NEGF) formalisms. The proposed device exhibits an excellent spin-dependent transport behavior within the bias window of [-0.5 V, 0.5 V]. In parallel configuration (PC), the device offers an ideal spin filtration efficiency of almost 100% within the bias range of [-0.4 V, 0.4 V], and in antiparallel configuration (APC), it exhibits negative differential resistance (NDR), dual-spin rectification, and dual-spin filtration effects. Also, a high tunnel magnetoresistance (TMR) of 1.2 x 10(5)% is achieved. To validate the aforementioned effects, the transmission spectra along with the area enclosed by the curve, eigenvalues, eigenstates, and quantum conductance have also been analyzed. In addition, the impact of hybridization and torsion defects on the spin-dependent transport phenomenon through trans-polyacetylene has been investigated. Furthermore, the modelled device is observed to exhibit the spin Seebeck effect in PC under the influence of temperature gradient. The proposed device may stand as a good contender for various spintronic and spin caloritronic applications. (C) 2022 Vietnam National University, Hanoi. Published by Elsevier B.V.
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| 4. |
- 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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