Transformation Of Rust In The Presence Of Mangrove (Rhizophoru Apiculuta)Tannins And Phosphoric Acid.

The known hazardous effects of most synthetic corrosion inhibitors are reasons to search for safer and environmentally friendly natural products. The role of mangrove (Rhizaphora apiculata) tannins and phosphoric acid as rust converters by phaser transformation studies is evaluated

Determination of total phenol, condensed tannin and flavonoid contents and antioxidant activity of Uncaria gambirextracts

Uncaria  gambir,  a  well  known  Southeast  Asia  plant  have  been  previously used as an alternative medicine for treatment such as diarrheal, sore throat and spongy  gums.  Due  to  its  useful  properties,  in  this  study  we  have  analysed  the total  phenol,  condensed  tannin,  flavonoid  content  and  antioxidant  activity  of Uncaria  gambir in  three  different  solvent  extracts.  Characterization  and quantification analysis using Fourier Transform Infrared (FTIR) spectroscopy and reverse  phase-high  performance  liquid  chromatography  (RP-HPLC)  has confirmed  that  the  major  chemical  constituents  of  Uncaria  gambir are  mainly catechins.  It  was  revealed  that  the  ethyl  acetate  gambir  extract  gives  the highest  catechin  content  and  antioxidant  activity  compared  with  other  solvent extracts.Key words: Uncaria gambir, antioxidant activity, condensed tannin, flavonoid

The Usability of E-learning Platforms in Higher Education: A Systematic Mapping Study

The use of e-learning in higher education has increased significantly in recent years, which has led to several studies being conducted to investigate the usability of the platforms that support it. A variety of different usability evaluation methods and attributes have been used, and it has therefore become important to start reviewing this work in a systematic way to determine how the field has developed in the last 15 years. This paper describes a systematic mapping study that performed searches on five electronic libraries to identify usability issues and methods that have been used to evaluate e-learning platforms. Sixty-one papers were selected and analysed, with the majority of studies using a simple research design reliant on questionnaires. The usability attributes measured were mostly related to effectiveness, satisfaction, efficiency, and perceived ease of use. Furthermore, several research gaps have been identified and recommendations have been made for further work in the area of the usability of online learning

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

The effect of Tinospora crispa extracts as a natural mild steel corrosion inhibitor in 1 M HCl solution

The potential of Tinospora crispa extracts as a corrosion inhibitor of mild steel in 1 M HCl was determined using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy methods (EIS). Maximum inhibition was attained at the concentration of 800 and 1000 ppm for TCDW (T. crispa water extract) and TCAW (T. crispa acetone–water extract). The inhibition efficiencies of T. crispa extracts obtained from the impedance and polarization measurements were in good agreement where the maximum inhibition is around 70–80%. Potentiodynamic polarization measurement studies revealed that T. crispa extracts behave predominantly as an anodic inhibitor. The adsorption of T. crispa extracts was found to follow Langmuir’s adsorption model

Non-academic service quality: comparative analysis of students and faculty as users

The research focus was a non-academic service quality assessment within higher education. In particular, non-academic service quality perceptions of faculty and students were evaluated using a service profit chain. This enabled a comparison which helped understanding of non-academic service quality orientation from a key users' perspective. Data were collected using a self-completion questionnaire that was posted on Survey Monkey. A four point Likert scale without a mid-point was used to record respondent perceptions. In total 296 usable questionnaires (192 from students and 104 from faculty) were collected, representing a response rate of 17 percent. Key results indicated that on the whole service users (both faculty and students) were satisfied with non-academic services and this had a positive impact on their loyalty. However, in the case of students, there was a disconnect between loyalty and its 'productive' propagation to the external environment

Physicochemical of microcrystalline cellulose from oil palm fronds as potential methylene blue adsorbents

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