Isolation and identification of triterpenoid compounds from Couroupita guianensis Aubl.

In this report, the extracts from the fruit and leaves of Couroupita guianensis were isolated using chromatographic methods and investigated for chemical composition. Four triterpenoid compounds were isolated and identified as betulinic acid, oleanolic acid, β-amyrin and friedelin. Their chemical structures were interpreted based on modern spectra such as MS, NMR and compared with previously published spectral data

Design and Fabrication of Side channel Photonic Crystal Fiber

International audienc

Research and training partnership to assist policy and capacity building in improving food safety in Vietnam

This paper evaluated the implementation of an initiative for promoting risk-based approaches to improve food safety management in Vietnam. A Taskforce of Risk Assessment for Food Safety (Taskforce) was formed and consisted of researchers working on risk assessment and food safety, and representatives of the related ministries of Health and of Agriculture. We used the OECD Development Assistance Committee Evaluation Criteria as a framework for assessing the impact of the Taskforce with five evaluation areas – relevance, effectiveness, efficiency, impact and sustainability. They analysed current food safety policies, identified key constraints and opportunities, and conducted action research and capacity building to address these challenges in food safety. Stakeholder workshops helped determine priority food safety issues and activities. A series of hands-on training based on real-world case studies were organized and risk assessment curricula were developed and taught at universities to promote sustainability. Practical guidelines, text books, a special edition and policy briefs were published. The Taskforce provided technical support to a national food safety assessment commissioned by the World Bank and evidence for development partners. The Taskforce was institutionalized by a national university to have a formal role in implementing its activities. In conclusion, the Taskforce has brought experts in Vietnam to work together on prioritized topics of food safety risk assessment, assisted and informed ministries in implementing risk-based approaches for food safety management. It can be recommended as a way of institutionalising risk-based methods in countries new to the approach

New naphthalene derivative from the leaves of <i>Cassia grandis</i> L.

<p><i>Cassia grandis</i> is used for the treatment of skin disorders, back pain, aches, etc. in Vietnamese traditional medicine. In this paper, phytochemicals of the leaves were investigated. A new naphthalene derivative (<b>1</b>, cassgranon D) and, seven known compounds rutin (<b>2</b>), afzelin (<b>3</b>), quercitrin (<b>4</b>), epicatechin (<b>5</b>), (-)-epiafzelechin (<b>6</b>), isoquercitrin (<b>7</b>) and aloe emodin (<b>8</b>) were isolated from the ethyl acetate and methanol extracts. Their structures were elucidated by spectral evidences (UV, IR, MS, ¹H, ¹³C, DEPT, HSQC and HMBC NMR), as well as by comparing with published data.</p

Multiplex RT Real-Time PCR Based on Target Failure to Detect and Identify Different Variants of SARS-CoV-2: A Feasible Method That Can Be Applied in Clinical Laboratories

Shortly after its emergence, Omicron and its sub-variants have quickly replaced the Delta variant during the current COVID-19 outbreaks in Vietnam and around the world. To enable the rapid and timely detection of existing and future variants for epidemiological surveillance and diagnostic applications, a robust, economical real-time PCR method that can specifically and sensitively detect and identify multiple different circulating variants is needed. The principle of target- failure (TF) real-time PCR is simple. If a target contains a deletion mutation, then there is a mismatch with the primer or probe, and the real-time PCR will fail to amplify the target. In this study, we designed and evaluated a novel multiplex RT real-time PCR (MPL RT-rPCR) based on the principle of target failure to detect and identify different variants of SARS-CoV-2 directly from the nasopharyngeal swabs collected from COVID-19 suspected cases. The primers and probes were designed based on the specific deletion mutations of current circulating variants. To evaluate the results from the MPL RT-rPCR, this study also designed nine pairs of primers for amplifying and sequencing of nine fragments from the S gene containing mutations of known variants. We demonstrated that (i) our MPL RT-rPCR was able to accurately detect multiple variants that existed in a single sample; (ii) the limit of detection of the MPL RT-rPCR in the detection of the variants ranged from 1 to 10 copies for Omicron BA.2 and BA.5, and from 10 to 100 copies for Delta, Omicron BA.1, recombination of BA.1 and BA.2, and BA.4; (iii) between January and September 2022, Omicron BA.1 emerged and co-existed with the Delta variant during the early period, both of which were rapidly replaced by Omicron BA.2, and this was followed by Omicron BA.5 as the dominant variant toward the later period. Our results showed that SARS-CoV-2 variants rapidly evolved within a short period of time, proving the importance of a robust, economical, and easy-to-access method not just for epidemiological surveillance but also for diagnoses around the world where SARS-CoV-2 variants remain the WHO’s highest health concern. Our highly sensitive and specific MPL RT-rPCR is considered suitable for further implementation in many laboratories, especially in developing countries