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Essential oils isolated from leaves, twigs, fruit bark and seeds of Michelia tonkinensis collected in Muong Nhe Nature Reserve, Dien Bien province were obtained by hydrodistillation with yields of 1.5, 0.42, 0.16 and 4.6% respectively (v/w on dry weight basis). After analysis through GC, GC-MS and 13C NMR, 30, 34, 31 and 13 compounds (representing 96.4%, 96.8%, 97.1% and 99.9% of the whole composition, respectively) were identified in the leave, twig, fruit bark and seed essential oils. The main components were limonene (43.2%) and germacrene D (32.7%) in the leaf oil; limonene (67.1%) and germacrene D (10.4%) in the twig oil; limonene (66%) in the fruit bark oil; and safrole (90%) in the seed oil. Essential oils from the leaves and twigs showed strong inhibition against Staphyloccocus aureus. The fruit bark essential oil exhibited greater antibacterial potential against all 3 tested microorganisms (S. aureus, Escherichia coli and Candida albicans). The essential oil from seed displayed weak antibacterial activity against the three tested microorganisms. [ABSTRACT FROM AUTHOR]

Keteleeria davidiana (C.E.Bertrand) Beissn. is a species of conifer native to southern China, Laos and Vietnam. The species has been listed as vulnerable in Vietnam. Essential oil samples have been isolated from leaves, twigs and wood, and their compositions investigated for the first time by combination of chromatographic and spectroscopic techniques [GC-FID, GC-MS and13C NMR]. The composition of leaf essential oil was dominated by α-pinene (28.1%), β-pinene (15.8%) and (E)-β-caryophyllene (13.8%). Twig essential oil contained mainly α-pinene (37.9%) and β-pinene (24.7%) accompanied by (E)-β-caryophyllene (8.3%) and β-phellandrene (7.5%). Lastly, α-pinene (27.9%), α-terpineol (20.3%) and (E)-β-caryophyllene (20.8%) were predominant in wood essential oil. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the result of gamma knife radiosurgery (GKRS) for drug-resistant primary trigeminal neuralgia (TN). Methods: Patients who were diagnosed with drug-resistant primary TN were treated with GKRS at the Nuclear Medicine and Oncology Center, Bach Mai Hospital from January 2015 to June 2020. Using the pain rating scale of the Barrow Neurological Institute (BNI), follow-ups and evaluations were conducted at 1 month, 3 months, 6 months, and 9 month, and 1, 2 years, 3 years, and 5 years after radiosurgery. Comparisons of pain levels was performed before and after radiosurgery according to the BNI scale. Results: From January 2015 to June 2020, 33 patients were treated with GKS. There were 23 female patients and 10 male patients; the average age was 61.9. The average onset time of disease was 4.42 years. Among all patients, 84.8% of patients were relieved from pain and 78.8% were pain-free without medication. The mean time for pain relief was 3 months and was not related to the dose of GKS (<80 Gy and >80 Gy). The efficacy of pain relief is not related to blood vessel contact with the trigeminal nerve, the dose of GKS, and the onset of disease. The rate of recurrence after the first pain relief was low (14.3%). Conclusions: Gamma knife is an effective method for the treatment of primary drug-resistant TN, especially in elderly patients with underlying medical conditions. The analgesic effect does not depend on the presence of nerve-vascular conflict. [ABSTRACT FROM AUTHOR]

This paper presents the results of the first observation of airborne trace elements using Barbula Indica moss in Hai Phong city, one of the two largest seaport cities in Vietnam. A total of 39 moss samples were collected at 39 different locations in January 2020 in Hai Phong. Neutron activation analysis method was used to analyze the concentration of 36 chemical elements in the collected moss samples and the obtained data were compared with the data obtained in other regions of Vietnam, China and Europe. The level of chemical elemental contamination in the air of Hai Phong was categorized and the possible sources of pollutant emissions were identified by applying principal component analysis. [ABSTRACT FROM AUTHOR]

In Vietnam, a lack of evidence about the unexpected antibodies hinders the capabilities to prepare the necessary resources and personnel for treating patients with blood disorders. This study aimed to measure the rates of different unexpected antibodies in patients having blood orders in Vietnam. Study design and methods: A cross-sectional study was conducted at the National Institute of Hematology - Blood Transfusion, Vietnam on 5608 patients with blood disorders. Information was obtained from the medical records, blood transfusion forms, screening test forms. The prevalence rate of unexpected antibodies in patients with haematological disorders was 9.3%. The most prevalent occurrence was the presence of an atypical antibody type, accounting for 61% of patients. The co-occurrence of this atypical antibody type and other types of antibodies was also observed, with the respective occurrence rates of 23.9%, 10.1%, 3.8%, and 1.2% for the combination of two, three, four, and five unexpected antibody types. The presence of one type of unexpected antibody was predominant, namely anti-E, accounting for the highest proportion (32.9%), followed by anti-Mia (18.4%). Among the 125 patients, the most frequently observed combination of abnormal antibodies was anti-E with anti-c (14.3%) and anti-E with anti-Mia (3.4%). Among the cohort of 53 patients exhibiting three types of unexpected antibodies, the most prevalent combination observed was anti-c, anti-E, and anti-Mia (5.7%). This study revealed a prevalence rate of 9.3% in the presence of unexpected antibodies in patients with blood disorders. The occurrence of individual unexpected antibodies surpasses that of coordinated antibodies • 9.3% of patients with blood disorders had unexpected antibodies. • Anti-E and anti-Mia were predominant unexpected antibodies. • The most frequently observed combination was anti-E with anti-c and anti-E with anti-Mia. [ABSTRACT FROM AUTHOR]

This study investigated the chronology of heterogeneous, multilayered, and overlapped architectures by combining experiments with computer simulations of thermoluminescence (TL) dating. We proposed a heterogeneous and multilayered model based on the cylindrical configuration for both excavated and buried status. The obtained results indicated that our model was able to determine the chronology of architectures having multilayered and overlapped structures, which differs from those obtained using the conventional spherical and homogeneous model from ten to several hundred years. Our proposed model also explicitly exhibited the significant contributions of excavation, destruction, and radiation shielding to the accurate determination of chronology. Application of the proposed model to the Oc Eo archaeological site in Vietnam suggested that the actual chronologies of four investigated architectures should be around AD 615–953, whereas the homogeneous model predicted their chronologies of about one to several decades older. In particular, our study provided the first scientific evidence for the formation of an overlapped architecture in an architectural assembly at the Oc Eo site, namely there was an (older) architecture constructed around AD 794 and lasted for about 159 years before being destroyed, probably by the kingdom's historical upheavals. Since then, another (younger) architecture was built on top of the older one's foundation. Our findings, which are also in good agreement with the radiocarbon dating using accelerator mass spectrometry (AMS), are crucial for archaeology as they provide solid evidences for the historical argumentations associated to the mysterious ancient Funan kingdom that spread across many countries in Southeast Asia, including Southern Vietnam. They also open a new research approach towards re-dating the chronologies of controversial complex architectures, which can change our understanding on the history of many nations in the world. • A heterogeneous and multilayered model with cylindrical configuration was proposed. • Computer simulation combined with field and laboratory experiments were conducted. • Chronologies of multilayered and overlapped architectures were precisely determined. • Chronologies of two overlapped structures in a single architecture were distinguished. [ABSTRACT FROM AUTHOR]

In order to investigate the temporal and spatial variations of 14 physical and chemical surface water parameters in the Nhue and Day sub-river systems of Vietnam, surface water samples were taken from 43 sampling sites during the dry and rainy seasons in 2007. The results were statistically examined by Mann-Whitney U-test and hierarchical cluster analysis. The results show that water quality of the Day River was significantly improved during the rainy season while this was not the case of the Nhue River. However, the river water did not meet the Vietnamese surface water quality standards for dissolved oxygen (DO), biological oxygen demand (BOD(5)), chemical oxygen demand (COD), nutrients, total coliform, and fecal coliform. This implies that the health of local communities using untreated river water for drinking purposes as well as irrigation of vegetables may be at risk. Forty-three sampling sites were grouped into four main clusters on the basis of water quality characteristics with particular reference to geographic location and land use and revealed the contamination levels from anthropogenic sources.