The educational system across the world had drastically been affected due to the pandemic outbreak of COVID-19. In this circumstance, Teaching and learning shifted from traditional way which involves face-to-face interaction among teachers and students physically in a classroom, to online learning either synchronously or asynchronously. Therefore, the aim of this study is to monitor the level of students’ perception towards online learning during the ongoing COVID-19 pandemic situation. The study adopted the way of quantitative approach by conducting a survey which was collected via a standardized online questionnaire. Data collected from 699 respondents were analyzed using SPSS 23 software. In spite of having been failed to get theoretical and practical experience as well as expected results, majority of the respondents had positive perceptions towards online learning and accepted this as the new method of learning with online application tools. The outcomes of the study will facilitate educational institutions and policy makers to take this online learning process to the next level in a prospective way. Keywords: Online Learning, COVID-19, Pandemic, Bangladesh.

Dengue is one of the major mosquito-borne diseases that still threaten humans and kill countless people. It is caused by a positive-stranded RNA virus that included the family of Flaviviridae. Dengue fever is an exquisite feverish viral disease dispatched by Aedes mosquitoes' sting, posing any one of the four dengue viral serotypes. This virus transmits through a vertical transmission way using a full unique system. Unfortunately, there is no still effective developed vaccine to eradicate this disease. Computational methods were used in this work to build and we suggest a multi-epitope vaccination for the dengue virus in Asia. This work employed different immunoinformatics and bioinformatics databases to predict powerful epitopes on the dengue virus envelope protein utilizing in silico techniques. We identified a total of 14 epitopes from the target envelope protein by evaluating their ability to induce both innate and acquired immunity via T and B lymphocyte-mediated reactions. Epitope conservation was taken into account because Dengue virus is an RNA virus, and all selected epitopes were 100% conserved. Antigenicity of the final multi-epitope vaccine component was 0.7055. Disulfide engineering was conducted at an area of high mobility to improve vaccine protein stability. In addition, codon adaptation and in silico cloning were used to guarantee that the planned subunit vaccine in E. coli was expressed at a greater level. Lastly, a molecular docking and simulation analysis was carried out for the vaccination protein and the TLR-4 receptor in order to assess the binding free energy and stability of the combination for this reason, the suggested in silico vaccine has to be tested for safety and immunogenicity in order to guarantee an active immunity against the Dengue virus.

is known as toothache plant belongs to the family of Asteraceae. It is treated as a medicinal remedy like tuberculosis, illness, cough, rheumatism, and illness. This study was concentrated on the antioxidant, cytotoxic, antimicrobial & thrombolytic activities of methanol extract of leaves using in vitro model. The antioxidant activity was estimated as trolox equivalent antioxidant capacity utilizing the DPPH and reducing power tests. The plant extract was tested for its cytotoxic action using a brine shrimp lethality bioassay, thrombolytic activity using clot disruption, and antibacterial activity using a disc diffusion assay technique against four distinct gram-positive also gram-negative bacteria. ICvalue of standard ascorbic acid for DPPH was 7.8µg/ml and the IC50 of the methanol extract of leaves was 198.34µg/ml that was moderate effect at all compare with ascorbic acid. Thrombolytic assay of Streptokinase as a positive control showed 88.49% where the extract shows 18.69% lytic activity shows the assay. In this study, the sample of LC results of cytotoxicity assay was 1.431 µg/mL which can be treated as less activity. Moreover, the extracts showed low to moderate antibacterial activity against both gram-negative and gram-positive bacterial stains (zone of inhibition-10-26 mm). Vibrio Mimicus bacteria stains exhibited the highest level of activity, with a range of 23 for the diameter of the growth inhibition zone. The current review shows leaf extracts of may be used as a source of antioxidant and thrombolytic activity, as well as a significant source of antibacterial and anticancer substances. Further research is required to evaluate in-vivo the pharmacological activity of leaves in order to identify the essential metabolites and potential mechanisms.

Acemella oleracea is known as toothache plant belongs to the family of Asteraceae. It is treated as a medicinal remedy like tuberculosis, illness, cough, rheumatism, and illness. This study was concentrated on the antioxidant, cytotoxic, antimicrobial & thrombolytic activities of methanol extract of Acmella oleracea leaves using in vitro model. The antioxidant activity was estimated as trolox equivalent antioxidant capacity utilizing the DPPH and reducing power tests. The plant extract was tested for its cytotoxic action using a brine shrimp lethality bioassay, thrombolytic activity using clot disruption, and antibacterial activity using a disc diffusion assay technique against four distinct gram-positive and gram-negative bacteria. IC50 value of standard ascorbic acid for DPPH was 7.8µg/ml and the IC50 of the methanol extract of Acmella oleracea leaves was 198.34µg/ml that was moderate effect at all compare with ascorbic acid. Thrombolytic assay of Streptokinase as a positive control showed 88.49% where the extract shows 18.69% lytic activity shows the assay. In this study, the sample of LC50 results of cytotoxicity assay was 1.431 µg/mL which can be treated as less activity. Moreover, the extracts showed low to moderate antibacterial activity against both gram-negative and gram-positive bacterial stains (zone of inhibition-10-26 mm). Vibrio Mimicus bacteria stains exhibited the highest level of activity, with a range of 23 for the diameter of the growth inhibition zone. The current review shows leaf extracts of Acmella oleracea may be used as a source of antioxidant and thrombolytic activity, as well as a significant source of antibacterial and anticancer substances. Further research is required to evaluate in-vivo the pharmacological activity of Acmella oleracea leaves in order to identify the essential metabolites and potential mechanisms.