| 1. |
- 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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| 2. |
- Sharma, Neha Kapila, et al.
(författare)
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Electronic bandstructure modulation of MoX2/ZnO(X:S,Se) heterostructure by applying external electric field
- 2022
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Ingår i: SURFACES AND INTERFACES. - : Elsevier. - 2468-0230. ; 29
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Tidskriftsartikel (refereegranskat)abstract
- The electronic properties of 2-Dimensional Van der Waals heterostructure of MX2(M:Mo, X:S, Se) and graphenelike ZnO by applying an external electric field(EF) in the range -0.50V/angstrom to 1.0V/angstrom is studied using first principles calculations. The effect of the transverse electric field is measured in terms of modulation of the electronic energy bandgap and change in the band alignment properties. The bandstructure of MoS2/ZnO heterostructure(HS) shows an indirect bandgap of 1.61eV with a type-II band alignment and a large built-in electric field of 7.42eV with a valence band offset of 1.22eV across the interface. The bandstructure of MoSe2/ZnO shows a direct bandgap of 1.81eV with type-I alignment and a built-in electric field of 3.64eV with a band offset of 0.31eV. The charge density is localized on MoS2 and ZnO in VBM and CBM respectively in MoS2/ZnO HS, whereas in MoSe2/ZnO, both VBM and CBM are localized on MoSe2. With a perpendicular electric field applied across the HS, re-alignment of bandstructure and modulation of bandgap in both the HSs occurs. The energy bandgap increases linearly with the applied electric field for MoS2/ZnO(1.1-2.2eV) and remains almost constant (1.81eV) in the range -0.50V/angstrom to 0.50V/angstrom followed by a small decrease with an increase in electric field (1.60 for EF=+/- 1.0V/angstrom). A cross-over in the bandgap type from indirect(type-II)-> direct(type-I) in MoS2-ZnO and direct(type-I) to indirect(type-II) in MoSe2/ZnO has been observed at a critical value of electric field EF=0.75V/ angstrom. The cross-over in band structure is consistent with the charge transfer pattern observed on the application of electric field. Tuning the electronic bandgap and changing the band-alignment with an external electric field opens a way to design futuristic electronic and optical devices.
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| 3. |
- Abbasi, Rasha, et al.
(författare)
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IceCube search for neutrinos from GRB 221009A
- 2023
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Ingår i: Proceedings of 38th International Cosmic Ray Conference (ICRC 2023). - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- GRB 221009A is the brightest Gamma Ray Burst (GRB) ever observed. The observed extremelyhigh flux of high and very-high-energy photons provide a unique opportunity to probe the predictedneutrino counterpart to the electromagnetic emission. We have used a variety of methods to searchfor neutrinos in coincidence with the GRB over several time windows during the precursor, promptand afterglow phases of the GRB. MeV scale neutrinos are studied using photo-multiplier ratescalers which are normally used to search for galactic core-collapse supernovae neutrinos. GeVneutrinos are searched starting with DeepCore triggers. These events don’t have directionallocalization, but instead can indicate an excess in the rate of events. 10 GeV - 1 TeV and >TeVneutrinos are searched using traditional neutrino point source methods which take into accountthe direction and time of events with DeepCore and the entire IceCube detector respectively. The>TeV results include both a fast-response analysis conducted by IceCube in real-time with timewindows of T0 − 1 to T0 + 2 hours and T0 ± 1 day around the time of GRB 221009A, as well asan offline analysis with 3 new time windows up to a time window of T0 − 1 to T0 + 14 days, thelongest time period we consider. The combination of observations by IceCube covers 9 ordersof magnitude in neutrino energy, from MeV to PeV, placing upper limits across the range forpredicted neutrino emission.
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| 4. |
- Arora, Neha, et al.
(författare)
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NMR-Based Metabolomic Approach To Elucidate the Differential Cellular Responses during Mitigation of Arsenic(III, V) in a Green Microalga
- 2018
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Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 3:9, s. 11847-11856
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Tidskriftsartikel (refereegranskat)abstract
- Nuclear magnetic resonance (NMR)-based metabolomic approach is a high-throughput fingerprinting technique that allows a rapid snapshot of metabolites without any prior knowledge of the organism. To demonstrate the applicability of NMR-based metabolomics in the field of microalgal-based bioremediation, novel freshwater microalga Scenedesmus sp. IITRIND2 that showed hypertolerance to As(III, V) was chosen for evaluating the metabolic perturbations during arsenic stress in both its oxidation states As(III) and As(V). Using NMR spectroscopy, we were able to identify and quantify an array of ∼45 metabolites, including amino acids, sugars, organic acids, phosphagens, osmolytes, nucleotides, etc. The NMR metabolomic experiments were complemented with various biophysical techniques to establish that the microalga tolerated the arsenic stress using a complex interplay of metabolites. The two different arsenic states distinctly influenced the microalgal cellular mechanisms due to their altered physicochemical properties. Eighteen differentially identified metabolites related to bioremediation of arsenic were then correlated to the major metabolic pathways to delineate the variable stress responses of microalga in the presence of As(III, V).
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| 5. |
- Garg, K B, et al.
(författare)
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A comparative study of oxygen loss on in situ heating in PrMnO3 and BaMnO3
- 2011
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Ingår i: International Journal of Modern Physics B. - 0217-9792. ; 25:9, s. 1235-1250
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Tidskriftsartikel (refereegranskat)abstract
- We have thoroughly investigated the Oxygen loss in PrMnO3 and BaMnO3 the end members of the AMnO(3) system, on in situ heating in a reducing at This was done to drive some oxygen out from them and thus possibly alter the valence of the Mn cation. Sample characterization was done through X-ray diffraction and SEM measurements. The core-level photoemission point to oxygen loss from only BaMnO3 changing some of Mn4+ to Mn3+ in it, transfer of some spectral weight to the highly localized Fehrenbacher-Rice states and an increased Mn 3d-O 2p hybridization. Magnetization measurements show that at low temperatures, the samples depict a canted antiferromagnetic ordering.
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| 6. |
- Jena, Anjan Kumar, et al.
(författare)
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Strain-mediated ferromagnetism and low-field magnetic reversal in Co doped monolayer WS2
- 2022
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Strain-mediated magnetism in 2D materials and dilute magnetic semiconductors hold multifunctional applications for future nano-electronics. Herein, First principles calculations are employed to study the influence of biaxial strain on the magnetic properties of Co-doped monolayer WS2. The non-magnetic WS2 shows ferromagnetic signature upon Co doping due to spin polarization, which is further improved at low compressive (-2 %) and tensile (+2 %) strains. From the PDOS and spin density analysis, the opposite magnetic ordering is found to be favourable under the application of compressive and tensile strains. The double exchange interaction and p-d hybridization mechanisms make Co-doped WS2 a potential host for magnetism. More importantly, the competition between exchange and crystal field splittings, i.e. (Delta(ex) > Delta(cfs)), of the Co-atom play pivotal roles in deciding the values of the magnetic moments under applied strain. Micromagnetic simulation reveals, the ferromagnetic behavior calculated from DFT exhibits low-field magnetic reversal (190 Oe). Moreover, the spins of Co-doped WS2 are slightly tilted from the easy axis orientations showing slanted ferromagnetic hysteresis loop. The ferromagnetic nature of Co-doped WS2 suppresses beyond +/- 2 strain, which is reflected in terms of decrease in the coercivity in the micromagnetic simulation. The understanding of low-field magnetic reversal and spin orientations in Co-doped WS2 may pave the way for next-generation spintronics and straintronics applications.
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| 7. |
- Kumar, Vinay, et al.
(författare)
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Bioengineering of biowaste to recover bioproducts and bioenergy: A circular economy approach towards sustainable zero-waste environment
- 2023
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 319
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Tidskriftsartikel (refereegranskat)abstract
- The inevitable need for waste valorisation and management has revolutionized the way in which the waste is visualised as a potential biorefinery for various product development rather than offensive trash. Biowaste has emerged as a potential feedstock to produce several value-added products. Bioenergy generation is one of the potential applications originating from the valorisation of biowaste. Bioenergy production requires analysis and optimization of various parameters such as biowaste composition and conversion potential to develop innovative and sustainable technologies for most effective utilization of biowaste with enhanced bioenergy production. In this context, feedstocks, such as food, agriculture, beverage, and municipal solid waste act as promising resources to produce renewable energy. Similarly, the concept of microbial fuel cells employing biowaste has clearly gained research focus in the past few decades. Despite of these potential benefits, the area of bioenergy generation still is in infancy and requires more interdisciplinary research to be sustainable alternatives. This review is aimed at analysing the bioconversion potential of biowaste to renewable energy. The possibility of valorising underutilized biowaste substrates is elaborately presented. In addition, the application and efficiency of microbial fuel cells in utilizing biowaste are described in detail taking into consideration of its great scope. Furthermore, the review addresses the significance bioreactor development for energy production along with major challenges and future prospects in bioenergy production. Based on this review it can be concluded that bioenergy production utilizing biowaste can clearly open new avenues in the field of waste valorisation and energy research. Systematic and strategic developments considering the techno economic feasibilities of this excellent energy generation process will make them a true sustainable alternative for conventional energy sources.
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| 8. |
- Mallik, Sameer Kumar, et al.
(författare)
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Transition metal substituted MoS2/WS2 van der Waals heterostructure for realization of dilute magnetic semiconductors
- 2022
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Ingår i: Journal of Magnetism and Magnetic Materials. - : Elsevier. - 0304-8853 .- 1873-4766. ; 560
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Tidskriftsartikel (refereegranskat)abstract
- Atomically thin doped two dimensional (2D) layered materials manifest excellent magnetic features beneficial to the potential applications in spintronics. With the implementation of extensive first principles calculations, we demonstrate the MS2 (M = Mo, W) monolayers, as well as their van der Waals (vdW) hetero-bilayers as promising candidates for the successful realization of 2D dilute magnetic semiconductors with the incorporation of Mn and Co dopants. Under various pairwise doping configurations at different host atom sites, we report the electronic properties modifications induced change in magnetic exchange interactions. The magnetic coupling among the dopant pairs can be tuned between FM and AFM orderings via suitable doping adjustments. The developed interlayer exchange coupling between the vdW layers leads to strong and long-ranged ferromagnetic interactions which unleash robust magnetic moments with stable doping configurations. Our findings address the novel magnetic behavior of the layered vdW heterostructures and may further guide the future experimental efforts for the possible applications in modern electronics and nanoscale magnetic storage devices.
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| 9. |
- Poley, L., et al.
(författare)
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The ABC130 barrel module prototyping programme for the ATLAS strip tracker
- 2020
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Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 15:9
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Tidskriftsartikel (refereegranskat)abstract
- For the Phase-II Upgrade of the ATLAS Detector [1], its Inner Detector, consisting of silicon pixel, silicon strip and transition radiation sub-detectors, will be replaced with an all new 100% silicon tracker, composed of a pixel tracker at inner radii and a strip tracker at outer radii. The future ATLAS strip tracker will include 11,000 silicon sensor modules in the central region (barrel) and 7,000 modules in the forward region (end-caps), which are foreseen to be constructed over a period of 3.5 years. The construction of each module consists of a series of assembly and quality control steps, which were engineered to be identical for all production sites. In order to develop the tooling and procedures for assembly and testing of these modules, two series of major prototyping programs were conducted: an early program using readout chips designed using a 250 nm fabrication process (ABCN-250) [2, 3] and a subsequent program using a follow-up chip set made using 130 nm processing (ABC130 and HCC130 chips). This second generation of readout chips was used for an extensive prototyping program that produced around 100 barrel-type modules and contributed significantly to the development of the final module layout. This paper gives an overview of the components used in ABC130 barrel modules, their assembly procedure and findings resulting from their tests.
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| 10. |
- Sahoo, Sandhyarani, et al.
(författare)
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Electric Field-Modulated Charge Transfer in Geometrically Tailored MoX2/WX2 (X = S, Se) Heterostructures
- 2021
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 125:40, s. 22360-22369
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Tidskriftsartikel (refereegranskat)abstract
- Light-induced interlayer charge transfer in staggered-type heterostructures (HSs) in transition-metal dichalcogenides provides the opportunity to improve the performance of optoelectronic applications. Herein, we employ density functional theory to investigate the vertical electric-field-controlled interlayer charge transfer in stacked MoX2/WX2 (X=S, Se) HSs. Upon application of electric field from -3 to 3 V/nm, we observe the band-alignment transition, band inversion, and offset variations in these HSs. Furthermore, these electric fields are found to modulate charge localization/delocalization across the layers, which provides insight into charge transfer. The positive electric field is supposed to localize the charges in WS2, whereas the charges are localized in MoS2 at negative electric field. Based on charge localization/delocalization, our study suggests that the interlayer hole transfer upon MoS2 photoexcitation can be suppressed at higher positive electric fields, whereas electron transfer can be blocked by excitation of WS2. In contrast, negative electric fields (of -3 V/nm) can induce interlayer hole and electron transfer. Owing to the tunability of interlayer charge transfer by means of a vertical electric field, our findings bear paramount importance in modulating electron-hole recombination and charge-transfer time, which is beneficial for future optoelectronic devices.
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