A research on the performance of down-flow hanging sponge (DHS) reactor treating domestic wastewater

The aim of this study was to evaluate the performance of a down-flow hanging sponge (DHS) system in treating domestic wastewater. A pilot-scale of DHS system with a capacity of 60 L was designed and fabricated from polyvinyl chloride (PVC). The dimensions of DHS system are 1.5 m in height and square surface with 0.2 m in width, consists of three identical segments connected vertically in series. Each segment was filled by polyurethane sphere containing sponge. The total area of sponge and polyurethane sphere was 3,300 m2 m-3, density at 150 kg m-3, void ratio at 90%. DHS system was operated at ambient temperature within 82 days and stepwise increased of organic f rate from 0.5 to 1 and 1.5 kg COD m-3 d-1. The results showed that, this system performed well throughout the operational period and achieve the maximum removal of COD, BOD5, NH4+-N, and TN as 80%, 83%, 65% and 60%. The effluent of wastewater from DHS system achieved the requirement for National technical regulation on domestic wastewater of Vietnam type B QCVN 14:2008/BTNMT. In conclusion, the performance of DHS system indicated a high potential for application in removing organic matter and converting nitrogen ammonia to nitrogen nitrate, however it did not perform well for the removal of total nitrogen, it is necessary to study further by providing an anoxic zone in the system to enhance the treatment of nutrient in wastewater

Adopting the Hirschman–Herfindahl Index to estimate the financial sustainability of Vietnamese public universities

Over several decades, the Vietnamese government has increasingly cut its investment in the public higher education system and has also introduced a cost-sharing mechanism. Under this scheme, Vietnamese public universities have been seeking other sources of revenue. Despite the bold emphasis on the need for revenue diversification in higher education in Vietnam, there is little empirical evidence of the status quo of Vietnamese public higher education finance. The purpose of this paper was to fill this research gap by using the Hirschman–Herfindahl Index to estimate the degree of financial diversity in 51 public universities in Vietnam between 2015 and 2017. Our findings revealed that all institutions in this study were unsustainable due to their weak financial diversity. Suggestions for policy makers and university leaders that may enhance financial sustainability include the adoption of performance-based financial allocations and the implementation of capacity-building programs for universities with regard to fund-raising and entrepreneurship skills

Seasonal Prediction of Surface Air Temperature across Vietnam Using the Regional Climate Model Version 4.2 (RegCM4.2)

To investigate the ability of dynamical seasonal climate predictions for Vietnam, the RegCM4.2 is employed to perform seasonal prediction of 2 m mean (T2m), maximum (Tx), and minimum (Tn) air temperature for the period from January 2012 to November 2013 by downscaling the NCEP Climate Forecast System (CFS) data. For model bias correction, the model and observed climatology is constructed using the CFS reanalysis and observed temperatures over Vietnam for the period 1980–2010, respectively. The RegCM4.2 forecast is run four times per month from the current month up to the next six months. A model ensemble prediction initialized from the current month is computed from the mean of the four runs within the month. The results showed that, without any bias correction (CTL), the RegCM4.2 forecast has very little or no skill in both tercile and value predictions. With bias correction (BAS), model predictions show improved skill. The experiment in which the results from the BAS experiment are further successively adjusted (SUC) with model bias at one-month lead time of the previous run showed further improvement compared to CTL and BAS. Skill scores of the tercile probability forecasts were found to exceed 0.3 for most of the target months

A modern purification by accelerated solvent extraction and centrifugal partition chromatography and biological evaluation of capsaicin from Capsicum chinense

A special alkaloid compound known as capsaicin, which can only be found in the fruit of the Capsicum plant, was isolated and tested for its anti-inflammatory activity. The purpose of this work is to establish a simple and quick approach for capsaicin purification utilizing centrifugal partition chromatography (CPC) as well as an effective method - accelerated solvent extraction (ASE), for extracting capsaicin from Capsicum chinense. After purification, capsaicin was validated by HPLC-DAD at 281 nm to be > 90% purity. The in vivo anti-inflammatory activity of the isolated capsaicin was also investigated, and the IC50 value of the capsaicin was determined to be 57.61 µg/mL. The current work emphasizes how an ASE and CPC system may combine to extract high-purity capsaicin from Capsicum chinense, which have the anti-inflammatory activity, as we evaluated in the experiment

Evaluating the initial result of transanal and transvaginal NOTES for colorectal cancer

Objective: Natural Orifice Transluminal Endoscopic Surgery (NOTES) is an important evolution in minimally invasive surgery (MIS) nowaday. This paper presents the techniques and early results of the pure transanal and transvaginal laparoscopies (NOTES) used for the treatment of colorectal cancer. Material and method: Prospective studies were conducted at Hue Central Hospital, Vietnam. Patients: From December 2013 to September 2015, 22 cololorectal cancer patients (18 rectum, 3 sigmoid tumors and 1 descending colon), adenocarcinoma, T≤ T3N1M0. Methods: The patients were placed in lithotomy and Trendelenburg positions, and the lone-star retractor was placed in the anus (rectum cancer) or vagina (sigmoid cancer). The surgical cavity was then inflated with CO 2 and set at 12 mm/Hg. Dissection was continued until inside of the abdominal cavity (transanal technique). After that, the rectum was pushed into the abdominal cavity. The IMA and IMV were divided (TME included) in both techniques. After finishing dissection, the specimens were pulled out through the anus or vagina to prepare anastomosis. Coloanal and colorectal anastomosis were either hand-sewn (6 cases) or sealed with EEA staplers (16 cases). Results: 2 patients needed one more 5 mm umbilical port in RLQ, 2 patients needed two 5 mm trocars (post radiation hemorrhage, and urethral perforation). One patient converted to open and 1 patient converted to the HYBRID-NOTES procedure. The operation time was 258±40 (190-300) minutes. All patients required minimal analgesia. Bowel movement returned on the first day to 16 patients (average: two days, maximum: three days). The hospital stay was 7±2.8 (4-14) days. Kirwan classification (sphincter function) was very good (stage I: 18). Conclusions: Pure transanal and transvaginal laparoscopies for the treatment of colorectal cancer are feasible and safe. We believe that this is the first pure transvaginal laparoscopy (NOTES) for human in the world. A multicentric study in a large numbers of patients and a long follow-up is necessary

Evaluation of the Luminex xTAG Respiratory Viral Panel FAST v2 assay for detection of multiple respiratory viral pathogens in nasal and throat swabs in Vietnam.

BACKGROUND: Acute respiratory infections (ARI) are among the leading causes of hospitalization in children ≤5 years old. Rapid diagnostics of viral pathogens is essential to avoid unnecessary antibiotic treatment, thereby slowing down antibiotic-resistance. We evaluated the diagnostic performance of the Luminex xTAG Respiratory Viral Panel FAST v2 against viral specific PCR as reference assays for ARI in Vietnam. METHODS: Four hundred and forty two nose and throat swabs were collected in viral transport medium, and were tested with Luminex xTAG Respiratory Viral Panel FAST v2. Multiplex RT-PCR and single RT-PCR were used as references.    Results: Overall, viral pathogens were detected in a total count of 270/294 (91.8%, 95% CI 88.1-94.7) by the Luminex among reference assays, whilst 112/6336 (1.8%, 95% CI, 1.4-2.1) of pathogens were detected by the Luminex, but not by reference assays. Frequency of pathogens detected by Luminex and reference assays was 379 and 292, respectively. The diagnostic yield was 66.7% (295/442, 95%CI 62.1-71.1%) for the Luminex assay and 54.1% (239/442, 95% CI, 49.3-58.8%) for reference assays. The Luminex kit had higher yields for all viruses except influenza B virus, respiratory syncytial virus, and human bocavirus. High agreements between both methods [mean (range): 0.91 (0.83-1.00)] were found for 10/15 viral agents. CONCLUSIONS: The Luminex assay is a high throughput multiplex platform for rapid detection of common viral pathogens causing ARI. Although the current high cost may prevent Luminex assays from being widely used, especially in limited resource settings where ARI are felt most, its introduction in clinical diagnostics may help reduce unnecessary use of antibiotic prescription

The 80-year development of Vietnam mathematical research: Preliminary insights from the SciMath database on mathematicians, their works and their networks

Starting with the first international publication of Le Van Thiem (Lê Văn Thiêm) in 1947, modern mathematics in Vietnam is a longstanding research field. However, what is known about its development usually comes from discrete essays such as anecdotes or interviews of renowned mathematicians. We introduce SciMath—a database on publications of Vietnamese mathematicians. To ensure this database covers as many publications as possible, data entries are manually collected from scientists’ publication records, journals’ websites, universities, and research institutions. Collected data went through various verification steps to ensure data quality and minimize errors. At the time of this report, the database covered 8372 publications, profiles of 1566 Vietnamese, and 1492 foreign authors since 1947. We found a growing capability in mathematics research in Vietnam in various aspects: scientific output, publications on influential journals, or collaboration. The database and preliminary results were presented to the Scientific Council of Vietnam Institute for Advanced Study in Mathematics (VIASM) on November 13th, 2020

Craniometrics reveal "two layers" of prehistoric human dispersal in eastern Eurasia

This cranio-morphometric study emphasizes a "two-layer model" for eastern Eurasian anatomically modern human (AMH) populations, based on large datasets of 89 population samples including findings directly from ancient archaeological contexts. Results suggest that an initial "first layer" of AMH had related closely to ancestral Andaman, Australian, Papuan, and Jomon groups who likely entered this region via the Southeast Asian landmass, prior to 65–50 kya. A later "second layer" shared strong cranial affinities with Siberians, implying a Northeast Asian source, evidenced by 9 kya in central China and then followed by expansions of descendant groups into Southeast Asia after 4 kya. These two populations shared limited initial exchange, and the second layer grew at a faster rate and in greater numbers, linked with contexts of farming that may have supported increased population densities. Clear dichotomization between the two layers implies a temporally deep divergence of distinct migration routes for AMH through both southern and northern Eurasia

Provenance, routing and weathering history of heavy minerals from coastal placer deposits of southern Vietnam

Heavy mineral rich sands along the coastal margin of southern Vietnam often contain commercial deposits of ilmenite and zircon but their origin is unknown. A multi-method approach based on petrology, geochemistry and detrital zircon geochronology was used to define the provenance and transport history of these mainly Quaternary sands. A trend of progressive enrichment of ilmenite TiO2 content, from north to south, was observed. This reflects increased levels of weathering attributed to a wider coastal margin and shelf in the south combined with a succession of erosion and reburial events associated with interstadial and interglacial sea-level changes. Weathering took place during lowstands. Detrital zircon U-Pb age signatures collected from 25 major river outlets along the coast of Vietnam helped to locate potential sand sources. Prominent age groups spanning 90-120 Ma and 220-250 Ma with a minor group at 400-500 Ma are present in all of the detrital zircon U-Pb age distributions of contemporary beach sands and Quaternary coastal dune placer deposits. Proterozoic grains are also present but constitute < 10% of dated grains. The main source terrain for the placer sands is southern Vietnam where there are widespread outcrops of Mesozoic magmatic rocks. Detrital zircon U-Pb age signatures from river sands that drain this area are identical to zircon age distributions in placer sands. River sands from northern Vietnam, the Mekong and its delta contain abundant Paleozoic and Proterozoic zircons, which are largely absent from the placer sands, and so are ruled out as primary sources