Vietnam Journal of Science, Technology and Engineering

3-16

Authors: Sum Nguyen

Let Pk the graded polynomial algebra F2[x1,x2,...,xk] with the degree of each generation x1 being 1, where F2 denote the prime field of two elements, and let GLk be the general linear group ober F2 which acts regularly on Pk. We stydy the algebraic transfer contructed by Singer [[1] using the technique of the Prtersin hit problem. This subspace of F2x.aPk consisting of all the GLk-invariant classes of degree d. In this paper, by using the results on the Peterson hit problem we prevent the proof of the fact that the Singer algebraic transfer is an isomorphism for k<=3. This result has been proved by Singer in [1] for k<=2 and by Boardman in [2] for k=3. We show that the forth Singer tranfer is also an isomorphism in certain internal degrees. This results is new and it is different from the ones Bruner, Ha and Hung [3], Chon and Ha [4], Ha [5], Hung and Quynh [6], Nam [7].

23-27

Authors: Hung Viet Pham*, Thi Kim Trang Pham, Viet Nga Dao

Arsenic contamination in groundwater and its effect on human health has been a growing concern over recent decades. Some of the most severe incidents occurred in South and Southeast Asia, including the Red river delta, Vietnam. The highest concentration of arsenic found in the Red river delta was 810 μg/L, 16 times higher than the standard guidelines given by WHO for levels of arsenic concentration in groundwater (50 μg/L). However, the contamination levels were not uniform in the whole area. The arsenic levels might be affected by natural factors such as the characteristics of the aquifer, the chemical composition of groundwater and by human activities such as the exploitation of groundwater in the urban and industrial areas or irrigation in rural areas. Due to the complex mobilisation of arsenic in sediment and groundwater, questions remain about arsenic distribution, which are yet to be answered and are in need of further study.

38-41

Authors: Sang Ngoc Nguyen*, Viet Quoc Tran, Quang Van Vu

Idiopathic nephrotic syndrome (INS) is a major manifestation of chronic idiopathic glomerulonephritis and a common disease in children. The cause and pathogenesis of the disease have not been clarified so far. The treatment is usually a long-term process, from a few months to several years, even decades, including the period of hospitalisation, outpatient treatment period and follow-up period after treatment. The INS patients are negatively affected by the disease and its treatment process. The aim of this study is to assess the health-related quality of life (QOL) of children with INS according to clinical types in Haiphong Children’s Hospital. Object: Describe some factors related to the QOL of children with INS. Subjects:71 patients diagnosed with INS, who are being monitored and treated at Haiphong Children’s Hospital from 10/2015 to 05/2016. Methods: Prospective studies, descriptive cross-sectional. QOL of the patients is assessed by the PedsQL 4.0 scale; the higher score shows that the lower QOL. Results: The general QOL score of children with INS (21.24±13.91) was higher than normal children (16.98±10.20). Children with steroid-resistant INS have a higher score (31.62±14.32) than children with steroid-dependent (20.57±9.08) and responsive INS (14.58±6.83). The QOL score of children with one of the symptoms Cushing’s face, hirsutism or acne are significantly higher than children without the corresponding symptoms. Children who finished their treatment had a lower score (15.47±7.42) than children being treated (21.33±10.23). The average QOL score has a linear correlation with the duration of INS. Conclusion: The general QOL of children with INS substantially declined compared with that of healthy children. The QOL of children with steroid-dependent and resistant INS is lower than that of the children with steroid-responsive type. The QOL of children with one of the symptoms Cushing’s face, hirsutism or acne is significantly lower than that of children without the corresponding symptoms. The QOL of children who completed treatment is higher than the group being treated. The longer the duration of treatment, the more the children’s QOL declined

46-49

Authors: Thi Ngoc Lan Nguyen, Huu Quan Nguyen, Thi Hanh Nguyen, Thi Mai Thu Lo, Hoang Mau Chu*

Jewels of Opar (Talinum paniculatum) is a herbaceous plant known for its highly medicinal value. This medicinal plant is listed in the Red List of Vietnam’s medicinal plants and in the handbook of Vietnam’s medicinal plants, both documents warranting its necessity for protection. Jewels of Opar contains bioactive substances such as phytosterols, saponins, flavonoids, tannins, steroids, and many other inorganic substances. Jewels of Opar plants collected in Thanh Hoa, Vietnam, are tree-like herbs, their green trunks grows straight up and then branch out. The shapes of the leaves vary; they are generally oval or ovate-oblong in shape, with wavy veins. The flowers of this tree have five reddish purple wings, two sepals, more than ten stamens, and a spherical ovary. Both the fruits and their seeds are small and black. Tuberous roots are cylindrical with many small roots, and the tubers themselves are sweet and spicy. Internal transcribed spacer (ITS) region isolated from T. paniculatum plants in Thanh Hoa, Vietnam is 643 bp in length. Based on the nucleotide sequences of the ITS region and using the basic local alignment search tool (BLAST) in theNational Center for Biotechnology Information (NCBI), the Jewels of Opar samples collected in Thanh Hoa, Vietnam were determined to belong to T. paniculatum species, Talinumgenus, Portulacaceae.

68-72

Authors: Thi Thu Do*, Thi Hien Hoang, Thi Anh Thu Do*, Quang Ngan Pham, Hong Thai Giang, Ha Trung Bui, Trung Tran, Truong Giang Ho

In this research, we present the ZnO nanorods synthesized through the simple route of the hydrothermal method. The ZnO nanorods were developed through the application of only zinc acetate Zn(CH3COO)2 and ammonia solution, NH4OH, in the hydrothermal process at 1500C for 10 hours. The size of the ZnO nanorods was defined as approximately 300 nm in diameter and 1-2 μm in length. The fabrication of sensors was achieved through drop-coating of synthesized ZnO nanorods on Al2O3 substrates integrated with Au electrodes. Subsequent to the process of sintering done at 500oC for different durations, ZnO nanorod-based sensors were investigated when exposed to NO2 gas (1.5, 2.5, and 5 ppm) at room temperature under continuous UV-LED (385 nm) illumination. The correlation between NO2gas sensing performance and the optical property of the ZnO nanorods is discussed in detail. Herein, the defect concentration, particularly `in the surface region of the ZnO nanorods could be modified through sintering, and this indicates its importance in the reduction of response-recovery times and enhancement of high sensitivity to NO2 gas.

83-89

Authors: Van Khiem Mai*, Truong Minh Ha, Quang Nam Pham

The ability of simulation on large-scale global circulation, as well as temperature and rainfall over Vietnam area with different sea surface temperature (SST) boundary conditions by the Conformal-Cubic Atmospheric Model (CCAM) is presented in this paper. CCAM is a global circulation model, which may be used in the variable resolution mode to function as a regional climate model. That is, the model may be integrated with high horizontal resolution over the area of interest, with the resolution gradually decreasing as one moved away from the area of interest. The results show that model has well predicted large global circulation all over the global compared to Climate Forecast System (CFS) analysis data, two experiment of CCAM model were not too different with CFS model. For detailed forecasts in Vietnam region, the CCAM model will capture surface temperature compared to observed data with correlation coefficient above 0.85. Forecast temperature of CCAM tends to be lower than observed data, but the magnitude of error is not so much. Comparing the two experiments, forecast skill of CCAM_IRI is slightly better than CCAM_CFS. For rainfall, CCAM generally tends to forecast rainfall higher than observation data in summer and lower in winter. The predictive skill of rainfall in short lead times is better than others and skill of CCAM_CFS is significantly better than CCAM_IRI