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.
One important goal for any developing country is to establish and provide electric power for its citizens; an endeavor initiated by the Government of Bangladesh many years ago. Renewable energy is a ...key component for development and Bangladesh has already made significant strides in reaching most of the country's population; both in Urban and Rural areas. The renewable energy projects initiated by the Government are helping Private sector, Non-Government Organizations (NGOs), and Micro-Finance institutions expand the solar energy program, both in terms of Sustainability and Commercial viability. These projects are increasing awareness among consumers and suppliers of the benefits and the correct use of solar home systems. The study, therefore, investigates whether solar business industry should implement a common strategy to position itself in all over the country. The Authors outline the benefits of using solar energy and the possibilities regarding solar energy system in Bangladesh as well as the problems relating to this sector.
Data was collected via questionnaire on a systematic random basis. The results indicate significant business potentials of the solar energy sector. As perception towards renewable energy product is being measured in terms of convenience, country made perception and as a whole it will enhance the comfort of the society to some extent but also it will contribute in the economy if proper sales and service is given to the consumers. The authors recommend the initiation of motivational awareness by policy developers of Bangladesh, for the achievement of sustainable growth in the production of renewable energy.
Species substitution, the use of a low value fish in place of a high value fish, is the biggest problem in international trade and the leading cause of fraud in the fisheries arena sector. Current ...DNA barcoding systems have partly solved this problem but also failed in many instances to amplify PCR targets from highly processed products because of the degradation of a longer barcode marker (~650bp). In the present study, a novel mini barcode marker (295bp) was developed to discriminate fish species in raw and processed states forms. The barcode primers were cross-tested against 33 fish species and 15 other animal species and found to be universal for all the tested fish varieties. When 20 commercial fish products of five different categories were screened, all commercial fish sample yielded positive bands for the novel fish barcode. PCR product was sequenced to retrieve the species IDs that reflected 55% (11/20) of Malaysian fish products were mislabeled.
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•Novel COI mini barcode (295bp) to authenticate fish species.•It was validated against 33 fish and 15 non-fish species.•It is suitable to be used as a universal fish positive control under mixed matrices.•The screening of 22 Malaysian fish products revealed 55% fraud labelling.
•To illustrate numerically a High Sensitivity D Shaped Dual Core Photonic Crystal Fiber SPR Biosensor modeling employing gold coat.•To investigate Sensing characteristics with the modal analysis ...based finite element method (FEM) incorporating COMSOL multiphysics software.
In this paper, an enhanced performance of dual core D-shape photonic crystal fiber utilizing surface plasmon resonance (DD-PCF-SPR) based sensor is numerically proposed and analyzed. The thickness of gold and pitch parameter are optimized to 30 nm and 1.9 um, respectively, which ensures superior sensor performance. It is revealed; at optimized geometrical parameter, the offered sensor displays a supreme wavelength sensitivity of 8000 nm/RIU, wavelength resolution of 1.25 × 10−5 RIU, a supreme amplitude sensitivity of 700 RIU−1, amplitude resolution 1.7857 × 10−5 RIU and a figure of merit (FoM) of 138 RIU−1 due to the analyte refractive index changing from 1.47 RIU to 1.48 RIU. The identifying features are investigated using modal analysis based finite element method (FEM) incorporating COMSOL commercial software. Finally, a relative review is executed comparing amplitude sensitivity, resolution and wavelength sensitivity of the offered sensor with previously reported sensors. As high sensitivity, simple structure, and tremendous linear polynomial characteristics, the offered sensor will be a talented candidate for the detection of various biochemical and biological samples (DNA, mRNA, proteins, sugar).
•To illustrate a High Sensitivity circular Shaped Hollow Core Photonic Crystal Fiber.•The proposed structure is demonstrated consisting of all circular air holes with an external coating of Silver ...(Ag) and sensing layer.•To investigate Sensing characteristics with the modal analysis.•To obtain that the maximum amplitude and wavelength sensitivity.
This article numerically offers and analyses a hollow core circular shaped photonic crystal fiber-based surface plasmon resonance (CH-PCF-SPR) biosensor. The biosensor sensitivity is analyzed with applying a mode solver built finite element method (FEM) incorporating multi-physics software “COMSOL”. A nano film of silver is coated as sensing layer on the external surface for easy sensing and more practical realization. The biosensor unveils the highest wavelength sensitivity valued 21000 nm/RIU and amplitude sensitivity valued 2456 RIU−1, and corresponding wavelength resolution of 4.76 × 10−6 RIU and amplitude resolution of 4.07 × 10−6 RIU, respectively, using wavelength interrogation technique (WIT) and technique of amplitude interrogation (AIT), in detecting effective refractive index range 1.33 RIU and 1.42 RIU. Besides, the consequence of changing structural parameters like – pitch, diameter of air hole, various plasmonic metals and silver (Ag) layer thickness are also resulted in results section. The sensitivity of the offered sensor is analyzed to examine the means of spectral loss depth, resolution and amplitude sensitivity. In arrears to the modest scheme, highly sensitive and resolution nature, the offered design can be precisely applied in detection of bio molecular analytes
In this paper, an extremely birefringent PCF based on a modified decagonal (MD-PCF) arrangement is studied for broadband compensation covering the S-, C- and L-communication bands wavelength ranging ...from 1460 to 1625 nm. It is made known in theory that it is conceivable to attain negative dispersion coefficient about − 448 to − 835 ps/nm/km covering S-, C- and L-communication bands as well as a relative dispersion slope near to single mode fiber (SMF) of 0.0036 nm
. On the basis of simulation results incorporating finite-element method based COMSOL multiphysics software, birefringence is obtained as high as 1.7 × 10
, which is definately greater than conventional step-index fiber (SIF) and circular air- holes PCF so far. We also discuss the characteristics of chromatic dispersion, effective area and confinement loss of the designed PCF.
Multifilamentary Bi 2 Sr 2 CaCu 2 O x (Bi-2212) wire made by the powder-in-tube technique is the only high-temperature superconductor made in the round shape preferred by magnet builders. The ...critical current density ( J C ) of Bi-2212 round wire was improved significantly by the development of overpressure heat treatment in the past few years. Bi-2212 wire is commercially available in multiple architectures and kilometer-long pieces and is a very promising conductor for very high-field NMR and accelerator magnets. We studied the effects of precursor powder and heat treatment conditions on the superconducting properties and microstructure of recent Bi-2212 wires. Short samples of recent wire with optimized overpressure processing showed J C (4.2 K, 15 T) = 6640 A/mm 2 and J C (4.2 K, 30 T) = 4670 A/mm 2 , which correspond to engineering critical current densities J E (4.2 K, 15 T) = 1320 A/mm 2 and J E (4.2 K, 30 T) = 930 A/mm 2 .
Gelatin is widely used in many confectionery products such as gummy, candies, pastilles and marshmallows. However, the acceptance of gelatin in consumer goods largely depends on its animal origins. ...The main sources of gelatin are pig, cow and fish collagens that have differential acceptance in Halal, Kosher and Hindu foods. Currently, several simplex and duplex PCR assays are available for the determination of gelatin origins but those methods are not only time-consuming and costly but also cannot reveal all information in a single assay platform. For the first time, we documented here a tetraplex PCR assay involving eukaryotic, fish, bovine, and porcine control for the simultaneous detection of these species by a single, easy and reliable approach. The assay was optimized under pure and mixed gelatin matrices and validated by PCR product sequencing. Finally, 38 halal branded confectionery items were screened and 33, 2 and 3 of them yielded positive bands for bovine, porcine and eukaryotes, respectively. The detection limit was 0.1 to 0.001 ng DNA extracted from pure and mixed gelatins. The study is potentially useful in monitoring and certifying halal, kosher and vegetarian issues in processed foods, pharmaceuticals and cosmetics.
•Universal fish primers and multiplex PCR for bovine, porcine, and fish gelatine.•The detection limit was from 0.1 to 0.001 ng of DNA for pure and mixed gelatine.•Screening results of 38 confectionary items from Malaysian markets.
Shigellosis, caused by Shigella species, is a major public health problem in Bangladesh. To determine the prevalence and distribution of different Shigella species, we analyzed 10,827 Shigella ...isolates from patients between 2001 and 2011. S. flexneri was the predominant species isolated throughout the period. However, the prevalence of S. flexneri decreased from 65.7% in 2001 to 47% in 2011, whereas the prevalence of S. sonnei increased from 7.2% in 2001 to 25% in 2011. S. boydii and S. dysenteriae accounted for 17.3% and 7.7% of the isolates respectively throughout the period. Of 200 randomly selected S. sonnei isolates for extensive characterization, biotype g strains were predominant (95%) followed by biotype a (5%). Resistance to commonly used antibiotics including trimethoprim-sulfamethoxazole, nalidixic acid, ciprofloxacin, mecillinam and ampicillin was 89.5%, 86.5%, 17%, 10.5%, and 9.5%, respectively. All isolates were susceptible to ceftriaxone, cefotaxime, ceftazidime and imipenem. Ninety-eight percent of the strains had integrons belonging to class 1, 2 or both. The class 1 integron contained only dfrA5 gene, whereas among class 2 integron, 16% contained dhfrAI-sat1-aadA1-orfX gene cassettes and 84% harbored dhfrA1-sat2 gene cassettes. Plasmids of ∼5, ∼1.8 and ∼1.4 MDa in size were found in 92% of the strains, whereas only 33% of the strains carried the 120 MDa plasmid. PFGE analysis showed that strains having different integron patterns belonged to different clusters. These results show a changing trend in the prevalence of Shigella species with the emergence of multidrug resistant S. sonnei. Although S. flexneri continues to be the predominant species albeit with reduced prevalence, S. sonnei has emerged as the second most prevalent species replacing the earlier dominance by S. boydii and S. dysenteriae in Bangladesh.
Zinc ferrite samples were prepared by two different routes which are chemical co-precipitation and standard solid state double sintering method. Structural properties of ZnFe2O4 were determined, and ...initial particle size was found as 5 nm in the samples prepared by chemical co-precipitation technique. The XRD patterns showed the single phase of ZnFe2O4 spinel structure and confirmed by the lattice parameter and the unmixed hkl values for both the synthesis techniques. M-H curves at room temperature showed superparamagnetic nature of the samples sintered from 200°C to 600°C, synthesized by chemical co-precipitation technique. The Mössbauer analysis at room temperature showed a doublet which is the signature of superparamagnetic nature, and it is in agreement with the acquired M-H curves. The magnetization of ZnFe2O4 synthesized by chemical co-precipitation method was found higher than the magnetization of ZnFe2O4 synthesized by the solid-state double sintering method in the sintering temperature from 1100°C to 1300°C.
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