Last few decades, viruses are a real menace to human safety. Therefore, the rapid identification of viruses should be one of the best ways to prevent an outbreak and important implications for ...medical healthcare. The recent outbreak of coronavirus disease (COVID-19) is an infectious disease caused by a newly discovered coronavirus which belongs to the single-stranded, positive-strand RNA viruses. The pandemic dimension spread of COVID-19 poses a severe threat to the health and lives of seven billion people worldwide. There is a growing urgency worldwide to establish a point-of-care device for the rapid detection of COVID-19 to prevent subsequent secondary spread. Therefore, the need for sensitive, selective, and rapid diagnostic devices plays a vital role in selecting appropriate treatments and to prevent the epidemics. During the last decade, electrochemical biosensors have emerged as reliable analytical devices and represent a new promising tool for the detection of different pathogenic viruses. This review summarizes the state of the art of different virus detection with currently available electrochemical detection methods. Moreover, this review discusses different fabrication techniques, detection principles, and applications of various virus biosensors. Future research also looks at the use of electrochemical biosensors regarding a potential detection kit for the rapid identification of the COVID-19.
•Electrochemical biosensing platform helps to early diagnosis of pathogenic viruses.•Different electrochemical transduction system strategies are explained.•We covered more than 125 recent research articles on virus biosensors.•The advantages of each biosensor for COVID-19 detection are highlighted.•The advantages, drawbacks, and future perspectives of biosensors are discussed.
Abstract
Unconventional superconductors often feature competing orders, small superfluid density, and nodal electronic pairing. While unusual superconductivity has been proposed in the kagome metals
...A
V
3
Sb
5
, key spectroscopic evidence has remained elusive. Here we utilize pressure-tuned and ultra-low temperature muon spin spectroscopy to uncover the unconventional nature of superconductivity in RbV
3
Sb
5
and KV
3
Sb
5
. At ambient pressure, we observed time-reversal symmetry breaking charge order below
$${T}_{{{\rm{1}}}^{*}\simeq$$
T
1
*
≃
110 K in RbV
3
Sb
5
with an additional transition at
$${T}_{{{\rm{2}}}^{*}\simeq$$
T
2
*
≃
50 K. Remarkably, the superconducting state displays a nodal energy gap and a reduced superfluid density, which can be attributed to the competition with the charge order. Upon applying pressure, the charge-order transitions are suppressed, the superfluid density increases, and the superconducting state progressively evolves from nodal to nodeless. Once optimal superconductivity is achieved, we find a superconducting pairing state that is not only fully gapped, but also spontaneously breaks time-reversal symmetry. Our results point to unprecedented tunable nodal kagome superconductivity competing with time-reversal symmetry-breaking charge order and offer unique insights into the nature of the pairing state.
Eggplant or brinjal (Solanum melongena) is a popular vegetable grown throughout Asia where it is attacked by brinjal fruit and shoot borer (BFSB) (Leucinodes orbonalis). Yield losses in Bangladesh ...have been reported up to 86% and farmers rely primarily on frequent insecticide applications to reduce injury. Bangladesh has developed and released four brinjal varieties producing Cry1Ac (Bt brinjal) and is the first country to do so. We report on the first replicated field trials comparing four Bt brinjal varieties to their non-Bt isolines, with and without standard insecticide spray regimes. Results of the two-year study (2016-17) indicated Bt varieties had increased fruit production and minimal BFSB fruit infestation compared with their respective non-Bt isolines. Fruit infestation for Bt varieties varied from 0-2.27% in 2016, 0% in 2017, and was not significantly affected by the spray regime in either year. In contrast, fruit infestation in non-Bt lines reached 36.70% in 2016 and 45.51% in 2017, even with weekly spraying. An economic analysis revealed that all Bt lines had higher gross returns than their non-Bt isolines. The non-sprayed non-Bt isolines resulted in negative returns in most cases. Maximum fruit yield was obtained from sprayed plots compared to non-sprayed plots, indicating that other insects such as whiteflies, thrips and mites can reduce plant vigor and subsequent fruit weight. Statistically similar densities of non-target arthropods, including beneficial arthropods, were generally observed in both Bt and non-Bt varieties. An additional trial that focused on a single Bt variety and its isoline provided similar results on infestation levels, with and without sprays, and similarly demonstrated higher gross returns and no significant effects on non-target arthropods. Together, these studies indicate that the four Bt brinjal lines are extremely effective at controlling BFSB in Bangladesh without affecting other arthropods, and provide greater economic returns than their non-Bt isolines.
We present a systematic study of Re solute transport energetics in W using density functional theory calculations. The study focuses on substitutional solute diffusion in the presence of dislocation ...strain fields as a first step toward capturing the essential physics of solid solution hardening/softening in W-Re alloys. We calculate the heat of solution, the vacancy formation energy and the solute migration energy as functions of both hydrostatic and shear strains. Our results show that the vacancy formation energy scales with hydrostatic deformation, whereas it decreases with increasing shear strain. The migration energy decreases with hydrostatic deformation, whereas it displays path-length-dependent behavior under shear deformation. In addition, we compute the binding energies of an Re solute atom to the cores of screw and edge dislocations, and find the binding energy to be highest in the tensile lobe of the edge core. Finally, we obtain the dilatational stress due to a solute atom as a function of distance. Our calculations are then used to parameterize the jump rate of Re atoms in W as a function of the underlying stress state.
Analysis of convection driven by spatial periodic heating shows a wealth of responses due to Prandtl number dependence. The primary convection is delineated by the heating wavenumber and the ...secondary convection is characterized by the critical wavenumber established by an instability process. The resulting two-wavenumber dynamical system involves spatial parametric resonance leading to the wavenumber lock-in and the Rayleigh–Bénard (RB) instability producing unlocked states. Heating conditions leading to the co-existence of both types of states have been identified. Transition from the locked to the unlocked states produces states with a wide range of wavelengths and diverse patterns of movement. The possible secondary states are driven by a competition between the RB mechanism and the spatial parametric resonance. The relative strengths of these mechanisms change with Prandtl number $Pr$ resulting in four types of system responses. In the type A response occurring for $Pr>0.4$, parametric resonance dominates for the heating wavenumber $\alpha < 4.5$ resulting in the pattern lock-in between the primary and secondary convections whereas RB occurs for $\alpha > 10$. There is a wealth of possible convection patterns in the in-between zone where a small change of $\alpha$ results in a major change of flow pattern. In the type B response, which occurs for $0.19< Pr< 0.4$, the RB effect dominates eliminating the lock-in. The type C response, which occurs for $0.08 < Pr< 0.19$, is similar to type A but stronger spatial modulation extends the range of dominance of parametric resonance up to $\alpha =7$ while the RB effect dominates for $\alpha >10$ as in the type A response. A wealth of possible patterns occurs in the transition zone ($7<\alpha <10$). In the type D response, which occurs for $Pr<0.08$, the strong spatial modulation results in the formation of two separate critical stability curves, one resulting from the dominance of the spatial parametric resonance leading to the lock-in effect, and the other one corresponding to the dominance of the RB effect producing unlocked states. No continuous transition between both states can occur. Conditions where both distinct states can arise simultaneously were identified. Morphing between different patterns of secondary convection may occur in response to small changes in the heating pattern in types A and C, while such processes are not possible in types B and D.
In this experiment, a highly effective electrochemical sensor based on a molecularly imprinted polymer has been developed for ultrasensitive detection of dimetridazole. The sensor was made by ...incorporating of dimetridazole as a template molecule during the electropolymerization of poly-arginine on a glassy carbon electrode. The modified electrode GCE/P-Arg@MIP was characterized by voltammetric and microscopic techniques. Differential pulse voltammetry method was used to detect target analyte under the optimum condition. The DPV response to dimetridazole was linear at 0.1 × 10−9 to 10 × 10−6 mol L−1 (R2 = 0.996), with a method detection limit (S/N = 3) of 0.1 × 10−9 mol L−1. Moreover, the proposed sensor shows satisfactory recovery ranges for the determination dimetridazole in commercially available egg, milk and honey samples.
Display omitted
•Highly effective electrochemical MIP sensor developed for ultrasensitive detection of dimetridazole.•GCE/P-Arg@MIP electrode was fabricated via electrochemical deposition technique.•The proposed sensor exhibited a wide linear detection range with an LOD of 0.1 nM.•The GCE/P-Arg@MIP sensor was applied to detect analyte in egg, milk and honey.
Pumping using thermal waves Hossain, M.Z.; Floryan, J.M.
Journal of fluid mechanics,
07/2023, Letnik:
966
Journal Article
Recenzirano
Odprti dostop
It is shown that thermal waves applied on the bounding surface of a horizontal slot generate a pumping effect. Reynolds stress developed by the change in the flow field due to the thermal inertia ...associated with the penetration of the wave into the fluid interior drives the net fluid movement in the horizontal direction. The induced flow rate increases with the wave speed, but excessive wave speed reduces it as convection becomes limited only in the near-wall area. The excessive increase of the wavelength and its excessive decrease reduce the flow rate. An increase in the wave amplitude increases the flow rate with a saturation limiting its growth. Judicious selection of the wave speed and wavelength of a thermal wave provides a means for optimizing the wave-induced pumping. The magnitude of the pumping increases with a reduction of Prandtl number.
Genetic diversity of Nipah virus in Bangladesh Rahman, M.Z.; Islam, M.M.; Hossain, M.E. ...
International journal of infectious diseases,
January 2021, 2021-Jan, 2021-01-00, 20210101, 2021-01-01, Letnik:
102
Journal Article
Recenzirano
Odprti dostop
•The study added information about the genetic diversity and molecular characterization of Nipah virus (NiV) strains, both from bats and humans in Bangladesh.•This study provides molecular and ...methodological information for the early detection of NiV in the environmental samples to assess its epidemic potential in humans. It will also help in understanding the ecology of NiV.•The study revealed that the strains of NiV have been continuously evolving and NiV-BD genotype diverged from its ancestral during 1995 and formed two sublineages, NiV-BD 1 and 2. The occurrence of any particular sublineage of NiV strains was not limited to a specific outbreak region.
Nipah virus (NiV) infection, often fatal in humans, is primarily transmitted in Bangladesh through the consumption of date palm sap contaminated by Pteropus bats. Person-to-person transmission is also common and increases the concern of large outbreaks. This study aimed to characterize the molecular epidemiology, phylogenetic relationship, and the evolution of the nucleocapsid gene (N gene) of NiV.
We conducted molecular detection, genetic characterization, and Bayesian time-scale evolution analyses of NiV using pooled Pteropid bat roost urine samples from an outbreak area in 2012 and archived RNA samples from NiV case patients identified during 2012–2018 in Bangladesh.
NiV-RNA was detected in 19% (38/456) of bat roost urine samples and among them; nine N gene sequences were recovered. We also retrieved sequences from 53% (21 out of 39) of archived RNA samples from patients. Phylogenetic analysis revealed that all Bangladeshi strains belonged to NiV-BD genotype and had an evolutionary rate of 4.64 × 10−4 substitutions/site/year. The analyses suggested that the strains of NiV-BD genotype diverged during 1995 and formed two sublineages.
This analysis provides further evidence that the NiV strains of the Malaysian and Bangladesh genotypes diverged recently and continue to evolve. More extensive surveillance of NiV in bats and human will be helpful to explore strain diversity and virulence potential to infect humans through direct or person-to-person virus transmission.
Effective toughness of heterogeneous media Hossain, M.Z.; Hsueh, C.-J.; Bourdin, B. ...
Journal of the mechanics and physics of solids,
11/2014, Letnik:
71
Journal Article
Recenzirano
We propose a versatile approach to computing the effective toughness of heterogeneous media. This approach focusses on the material property independent of the details of the boundary condition. The ...key idea is what we call a surfing boundary condition, where a steadily propagating crack opening displacement is applied as a boundary condition to a large domain while the crack set is allowed to evolve as it chooses. The approach is verified and used to study examples in brittle fracture. We demonstrate that effective toughness is different from effective or weighted surface area of the crack set. Furthermore, we demonstrate that elastic heterogeneity can have a profound effect on fracture toughness: it can be a significant toughening mechanism and it can lead to toughness asymmetry wherein the toughness depends not only on the direction but also on the sense of propagation. The role of length-scale is also discussed.
Although high carbon martensitic steels are well known for their industrial utility in high abrasion and extreme operating environments, due to their hardness and strength, the compressive stability ...of their retained austenite, and the implications for the steels' performance and potential uses, is not well understood. This article describes the first investigation at both the macro and nano scale of the compressive stability of retained austenite in high carbon martensitic steel. Using a combination of standard compression testing, X-ray diffraction, optical microstructure, electron backscattering diffraction imaging, electron probe micro-analysis, nano-indentation and micro-indentation measurements, we determined the mechanical stability of retained austenite and martensite in high carbon steel under compressive stress and identified the phase transformation mechanism, from the macro to the nano level. We found at the early stage of plastic deformation hexagonal close-packed (HCP) martensite formation dominates, while higher compression loads trigger body-centred tetragonal (BCT) martensite formation. The combination of this phase transformation and strain hardening led to an increase in the hardness of high carbon steel of around 30%. This comprehensive characterisation of stress induced phase transformation could enable the precise control of the microstructures of high carbon martensitic steels, and hence their properties.
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