Assessment of hemostatic ability of biomaterial based on chitosan andEclipta prostrataL. extract.

The biomaterials based on chitosan andEclipta prostrataL. extract have been prepared by microemulsion method and solution method (with and without sodium tripolyphosphate (STPP) as a cross-linking agent). The main component inEclipta prostrataL. extract is flavonoid groups. The structure of the chitosan/extract biomaterials was studied by infrared spectroscopy. The chitosan/extract biomaterial using STPP cross-linker appeared an absorption band at 1152 cm-1attributed to the vibrations of C-O-P bonds, which proved that chitosan has crosslinked with STPP. The morphology of the biomaterials was investigated by the dynamic light scattering technique and field emission scanning electron microscopy. The obtained results showed that the particle size of the chitosan/extract biomaterials prepared by microemulsion method and solution method with STPP ranged from 68.06 nm to 1484 nm, with an average particle size of 304.9-1019 nm. The microemulsion method produced biomaterials with much smaller average particle size than the solution method using cross-linkers. The hemostatic ability of the biomaterials was better than that of the control sample based on the time of blood clotting formation and glomerular aggregation ability. The sample with the ratio ofE. prostrataL. extract: chitosan of 1:30 had the lowest hemostasis time (6 min 46 s) and its glomerular aggregation rate after 5 min was 13.05%. This indicated that the biomaterials based on chitosan andE. prostrataL. extract are promising for application in biomedicine as hemostatic materials.

Antimicrobial resistance and molecular characterization of Escherichia coli isolated from bovine mastitis samples in Nghe An province, Vietnam.

Background and Aim: Vietnam's dairy sector is in its early phase of large-scale farming development. Therefore, mastitis in cows is always a concern to farm owners. This study aimed to determine the antimicrobial susceptibility, resistance, and virulence-related genes of Escherichia coli isolated from bovine mastitis in Nghe An province of Vietnam. Materials and Methods: Fifty E. coli strains were isolated from the clinical cases and subjected to this study. All isolates were tested for antimicrobial susceptibility by the disk-diffusion method, as described by the Clinical and Laboratory Standards Institute. Antimicrobial and virulence genes were confirmed by polymerase chain reaction with specific primers. Results: All isolates were resistant to lincomycin and sulfamethoxazole and sensitive to gentamicin, while other antimicrobials showed resistance from 2% to 90%. Multidrug resistance was confirmed in 46% of isolates, and none of them were identified as extended-spectrum beta-lactamase producers. From fifty strains tested for antimicrobial and virulence genes, six isolates harbored tetA, 6 tetB, 13 sul1, 15 sul2, 2 Intimin (eae), 1 iutA, and 3 stx2. Conclusion: Antimicrobial and multidrug resistances are the main virulence factors of E. coli isolated from bovine mastitis in Vietnam. The virulence genes encoding adhesion, siderophore, Shiga-toxin-producing, and antimicrobials resistant were first reported in Vietnam with low prevalence and contributed to the pathogenesis.

Synthesis and characterization of some novel polythiophene derivatives containing pyrazoline.

Eight polythiophene derivatives containing pyrazoline side groups were synthesized by a chemical oxidative coupling polymerization using FeCl3. The crystal structures of four monomers were determined which confirm the almost perpendicular orientation of the thiophene and pyrazoline rings, while the other substituents are more coplanar. Analyses of IR, 1H-NMR, Raman and UV-Vis spectra demonstrated that the suggested polymerization was successful to generate the synthesized polythiophenes with the expected structures. The morphology of the synthesized polythiophenes was studied by SEM. The different substituents attached to the 1- and 3-positions of the pyrazoline side chain led to differences in optical properties, electrical conductivity, and thermal stability of the synthesized polythiophenes. By adding a pyrazoline side chain to polythiophenes, some polymers achieve good solubility, electrical conductivity of about 1.3 × 10-6 S/cm, high fluorescence intensity (above 40,000 a.u.) at 505-550 nm and thermal stability up to 590°C in the air.

Partially-covered fractal induced turbulence on fins thermal dissipation.

The impacts of partially-covered fractal grids induced turbulence on the forced convective heat transfer across plate-fin heat sink at Reynolds number ReDh = 22.0 × 103 were numerically and experimentally investigated. Results showed that partially covered grids rendered a higher thermal dissipation performance, with partially-covered square fractal grid (PCSFG) registering an outstanding increase of 43% in Nusselt number relative to the no grid configuration. The analyzation via an in-house developed single particle tracking velocimetry (SPTV) system displayed the findings of unique "Turbulence Annulus" formation, which provided a small degree of predictivity in the periodic annulus oscillations. Further assessments on PCSFG revealed the preferred inter-fin flow dynamics of (i) high flow velocity, (ii) strong turbulence intensity, (iii) vigorous flow fluctuations, (iv) small turbulence length scale, and (v) heightened decelerated flow events. These features stemmed from the coupling effects of multilength-scale fractal bar thicknesses in generating a veracity of eddy sizes, and a vertical segmentation producing heightened mass flow rate while inducing favourable wake-flow structures to penetrate inter-fin regions. Teeming effects of such energetic eddies within plate-fin array unveiled a powerful vortex shedding effect, with PCSFG achieving fluctuation frequency f = 18.5 Hz close to an optimal magnitude. The coaction of such traits limits the growth of fin boundary layers, providing superior thermal transfer capabilities which benefits the community in developing for higher efficiency heat transfer systems.

First record of Eyndhovenia (Mesostigmata: Gamasina: Spinturnicidae) from Vietnam.

Eyndhovenia is one of the twelve genera of Spinturnicidae which are highly specialised parasites of bats. Previously known hosts of this genus comprised 17 species of Old World bats: Eptesicus serotinus, Hipposideros larvatus, Miniopterus schreibersi, Myotis blythi, M. emarginatus, Pipistrellus pipistrellus, P. gaisleri, Rhinolophus axillaris, R. blasii, R. clivosus, R. cornutus, R. euryale, R. ferrumequinum, R. hipposideros, R. megachyllus, R. mehelyi, R. rouxi. Within Asia, Eyndhovenia was only recorded from two countries, China and Thailand. Between 2018 and 2020, we conducted a series of bats surveys and recorded of this genus from intermediate horseshoe bat, Rhinolophus affinis, in Vietnam. The present study exhibits the new record in both parasitological and geographical aspects.

Evaluation of air quality in Sunway City, Selangor, Malaysia from a mobile monitoring campaign using air pollution micro-sensors.

Due to the increase of the human population and the rapid industrial growth in the past few decades, air quality monitoring is essential to assess the pollutant levels of an area. However, monitoring air quality in a high-density area like Sunway City, Selangor, Malaysia is challenging due to the limitation of the local monitoring network. To establish a comprehensive data for air pollution in Sunway City, a mobile monitoring campaign was employed around the city area with a duration of approximately 6 months, from September 2018 to March 2019. Measurements of air pollutants such as carbon dioxide (CO2) and nitrogen dioxide (NO2) were performed by using mobile air pollution sensors facilitated with a GPS device. In order to acquire a more in-depth understanding on traffic-related air pollution, the measurement period was divided into two different time blocks, which were morning hours (8 a.m.-12 p.m.) and afternoon hours (3 p.m.-7 p.m.). The data set was analysed by splitting Sunway City into different zones and routes to differentiate the conditions of each region. Meteorological variables such as ambient temperature, relative humidity, and wind speed were studied in line with the pollutant concentrations. The air quality in Sunway City was then compared with various air quality standards such as Malaysian Air Quality Standards and World Health Organisation (WHO) guidelines to understand the risk of exposure to air pollution by the residence in Sunway City.

Orchid epiphytes do not receive organic substances from living trees through fungi.

Numerous studies of terrestrial orchids have demonstrated widespread partial mycoheterotrophy, particularly the possibility of obtaining organic matter from surrounding trees through a common fungal network. Fungi are also widespread in epiphytic orchid roots, but there have been no attempts to determine if epiphytes accept organic matter from the living stems of their phorophytes. We hypothesise that such transfer does not exist because epiphytes and phorophytes harbour different fungal communities. To test this hypothesis, we tagged three short Randia sp. trees with 13C-enriched CO2 and examined 13C transfer from the phorophyte into the epiphytic orchids Grosourdya appendiculata, Dendrobium oligophyllum and Gastrochilus sp. in Cat Tien National Park, (South Vietnam, Cat Tien National Park, plot size approx. 1 ha). The coincidence of fungal sequences in the orchid roots and in the branches on which they grew was also examined. We did not detect 13C label moving from phorophytes to epiphytes. Using Illumina sequencing, 162 fungal operational taxonomic units (OTUs) were detected. The fungal communities were significantly different between the roots of epiphytes and branches of phorophytes, although no strict fungal specificity at the species level was found in either epiphytes or phorophytes.

Anticancer effects of saponin and saponin-phospholipid complex of Panax notoginseng grown in Vietnam

Objective: To evaluate the antitumor activity both in vitro and in vivo of saponin–phospholipid complex of Panax notoginseng. Methods: The in vitro cytotoxic effect of saponins extract and saponin–phospholipid complex against human lung cancer NCI-H460 and breast cancer cell lines BT474 was examined using MTS assay. For in vivo evaluation of antitumor potential, saponin and saponin–phospholipid complex were administered orally in rats induced mammary carcinogenesis by 7,12-dimethylbenz(a)anthracene, for 30 days. Results: Our data showed that saponin–phospholipid complex had stronger anticancer effect compared to saponin extract. The IC50 values of saponin–phospholipid complex and saponin extract for NCI-H460 cell lines were 28.47μg/mL and 47.97μg/mL, respectively and these values for BT474 cells were 53.18μg/mL and 86.24μg/mL, respectively. In vivo experiments, administration of saponin, saponin–phospholipid complex and paclitaxel (positive control) effectively suppressed 7,12-dimethylbenz(a) anthracene-induced breast cancer evidenced by a decrease in tumor volume, the reduction of lipid peroxidation level and increase in the body weight, and elevated the enzymatic antioxidant activities of su-peroxide dismutase, catalase, glutathione peroxidase in rat breast tissue. Conclusions: Our study suggests that saponin extract from Panax notoginseng and saponin–phospholipid complex have potential to prevent cancer, especially breast cancer.

Home delivery in Luong Son, Hoa Binh

Background: There are about 600.000 deaths related to pregnancy and delivery in the world every year. In Vietnam, the rate of maternal death is 165/100.00. The majority of maternity and new born deaths occurred in the first week after delivery, especially 24 hours after delivery. Objective: To investigate the status of delivery and various factors related to home delivery and propose recommendations to reduce the rate of home delivery in Luong Son, Hoa Binh. Subject and method: The cross sectional study using a structured questionnaire with women who gave birth in 2003 was conducted in two communes of Luong Son district. Result: The home delivery rate was high (31.5%) and only 36.1% women decided themselves where to deliver. The main reasons for home delivery was perception related to last home delivery was normal, therefore this delivery should be at home (53.8%). Among 108 women interviewed, only 72% gave birth with the assistance of health professionals and 28% delivered with none health professional assistance. The rate of obstetric complications and new born death was relatively high among those that had homebirths. Conclusion: In order to increase the delivery rate at health care facilities and with the assistance of health professionals, there is required the cooperation of stakeholders for improving infrastructure, economic development, health education for increasing awareness of people on safe delivery. The public should change their perception, custom and behavior toward homebirths. Besides, the health sector should better manage the maternal health care program, monitor the pregnant women, plan the delivery dates and advocate their families (husbands and parent in laws) to take the women to deliver at the health care facilities.

The roles of Village Health Works (VHWs) and the influencing factors

Background: VHWs play an important role in primary health care. The Chuongmy district, Hatay province had only 50% of VHWs compared to the national rate of 90%. \r\n', u'Objectives: This study aims to describe the current activities of VHWs in Chuongmy district and identify the related factors. \r\n', u'Subjects and methods: The study adopted the cross sectional design, combined qualitative and quantitative data collection techniques with VHWs and the leaders of local authority and health facilities. \r\n', u'Results: VHWs play an important role in implementing health programs and health care activities in the villages. Almost all tasks and functions of VHWs were carried out in the villages but with different rate and quality. The major activities that VHWs carried out were preventive medicine and treatment of common diseases. Nevertheless, the quality of many activities should be improved. The performance and stability of VHWs depend on different factors such as training, income, qualification, support monitoring and supervision of local authority and health sectors. \r\n', u'Conclusions: The local authority and health sectors should have policies to provide update training to VHWs, incentives to retain them to work and enhance the supportive supervision of VHWs activities. \r\n', u'

Microarthropod community structures (Oribatei and Collembola) in Tam Dao National Park, Vietnam.

A study on the microarthropod community with special reference to species diversity of Oribatid and Collembola communities (Microarthropoda: Oribatei and Collembola) in Tam Dao National Park of Vietnam, a subtropical evergreen broad leaf alpine forest, was undertaken with the aim to explain how they are related to forest decline, and whether they can be used as bioindicators of forest plant succession. The results have shown that microarthropod community structures, particularly species diversity of oribatid and collembolan communities, are related to forest decline. Therefore they can be used as bioindicators of forest plant succession. In Tam Dao National Park, there was an inverse relation between species diversity of the oribatid and Collembola communities. The species diversity of the oribatid community gradually decreased with forest decline whereas the species diversity of the Collembola community gradually increased.