Tạp chí Phân tích Hóa, Lý và Sinh học

    The objective of this study were to compare the ability to detect V. cholerae and V.parahaemolyticus by conventional methods using TCBS (Thiosulfate Citrate Bile SaltsSucrose), CAV (CHROMagarTM Vibrio) medium and PCR method; and also to identify thepresence of virulence genes of V. cholerae, V. parahaemolyticus from fresh seafood by usingm-PCR technique. A total of 313 samples (126 from fillet fish, 52 from shrimp and 135 fromclam) were collected at Center of analytical services and experimentation in HCMC.PCRKeywords: Vibrio cholerae, Vibrio parahaemolyticus, virulence gene; fresh shrimp, fish filletand clam product.

In this study, the hydroxyapatite (HAP) nanoparticles were used as a reinforcement to improve the mechanical properties and thermal property for acrylic bone cements. Surface modification of origin HAP (oHAP) was performed by using solution method with vinyltrimethoxysilane coupling agent (VTMS). Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray (EDX) analysis revealed the presence of hydrolyzed VTMS on surface of modified HAP nanoparticles. Acrylic bone cements based on polymethylmethacrylate (PMMA) and origin HAP (oHAP) or modified HAP (mHAP) have been prepared and their properties have been investigated. The obtained results showed that mechanical properties of PMMA/mHAP bone cements were improved in comparison with those of PMMA/oHAP cements. With increasing oHAP content, tensile strength and flexural strength of PMMA/oHAP cements strongly decreased. On the contrary, tensile strength and flexural strength of PMMA/mHAP bone cements reached the highest values of 55.24 and 45.26 MPa at mHAP content of 5 wt.%, respectively. Thermal gravimetric analysis (TGA) showed that onset degradation temperature of PMMA/mHAP (10%) bone cement was lower than that of PMMA/oHAP (10%) bone cement, however, that of PMMA/mHAP (5%) bone cement was higher. Scanning electron microscopy (SEM) images confirmed that PMMA/oHAP and PMMA/mHAP bone cements exhibited multi-phase morphology with prepolymer, synthesized polymer, inorganic and pore phases. The mHAP particles dispersed regularly in the post synthesized PMMA matrix with size from 50 to 200 nm. This demonstrated the good effect of the modification of HAP by VTMS.

Vietnam is a major coffee exporter in the world with an estimated annual output of more than one million tons. From the production of green coffee, a large amount of defective green coffee beans arediscarded. The collection of these defective green coffee beans for medicinal purposes has made full use of natural resources, bringing great value in both economy and environment. The study was carried out with the following methods: Recovering of green coffee extract by impregnating in ethanol; Testing for antimicrobial activity; Syntheticing nano silver - green coffee AgNPs-GCB. The results showed that the high amount of extract obtained from discarded coffee beans reached 28.5-29.1%. Green coffee extract (GCB) has chlorogenic acid (CGA) reaching 6.7%, caffeine 2.7% and could be used in pharmaceutical chemicals and cosmetics. Green coffee extract, in addition to the known traditional medicinal effects, is also a biologically active substance, reducing sugar, a stable emulsifying support system in the production of nano-biomaterials to create nano-AgNPs-GCB for creating added value from waste for coffee production

    The investigation of pollution in the water wells of households living around the industry zone of Phu Hoi, Duc Trong District, Lam Dong Province has been carried out during the years of 2012-2013. The analytical result showed that the concentrations of As, Cd, Pb, Cu, Zn, Fe, Mn in samples of 15 water wells are lower than recommendation of QCVN 08:2008; however the contents of COD, BOD, Coliform, E.Coli in these sample are rather high, higher than that QCVN 08:2008 recommended.

    Pollution of heavy metals (such as Pb, Cd, ...) caused serious effects to theenvironment and human health. Through the survey of optimal conditions of AASmeasurement as well as factors effecting the CPE techniques such as time,temperature, speed centrifugal separation phase, reagent concentration,concentration of buffer solution, viscosity, surfactant, ... By combining technicalcloud point extraction (CPE) and method atomic absorption spectrometry (AAS) todetermine trace amounts of Pb, Cd in water. The recovery of metals is determinedafter the analysis process.Keywords: Cloud point extraction, atomic absorption spectrometry, Pb, Cd.1.

    Residues of Acrylamide (AA) in green tea and tea products were determined using liquid chromatography-tandem mass spectrometry to study their formation during green tea roasting process. Acrylamide (AA) has been found in various teas. This study was focussed on optimizing the roasting conditions using Central Composite Design (CCD) to produce superior quality tea products with low concentration of acrylamide. The roasting conditions used were temperatures in the range of of 120oC to 200oC and time ranging from 15 min to 40 min. Roasting conditions signifcantly (p

Trong quá trình sử dụng dầu diesel và nhiên liệu diesel sinh học, các vật liệu kim loại, hợp kim được dùng để sản xuất thùng nhiên liệu, đường ống, máy bơm, piston và các bộ phận khác của động cơ đốt sẽ có thể bị ăn mòn. Để khảo sát ảnh hưởng của nhiên liệu sinh học (BDF) với các kim loại, phổ biến nhất là đồng, hợp kim đồng, nhôm và hợp kim nhôm, thép và hợp kim thép không gỉ, nghiên cứu này đã tiến hành khảo sát sự hao tổn trọng lượng của một số vật liệu hợp kim khi tiếp xúc với các hỗn hợp hai loại nhiên liệu BDF và dầu mỏ khác nhau là B0 (dầu diesel), B5 (5% BDF trong dầu diesel), B10 (10% BDF trong dầu diesel), B20 (20% BDF trong dầu diesel) và B100 (100% BDF). Nhiệt độ thí nghiệm là40oC; thời gian tiếp xúc là 50 tuần. Sáu mẫu kim loại là Nhôm đúc (AC2A), Hợp kim nhôm (A2024P), Đồng (C1100P), Đồng kẽm 20% đồng thau (C2680P), Thép (JISG 3141) và Thép không gỉ (SUS 304). Kết quả cho thấy nhiên liệu diesel sinh học có tác dụng làm hao tổn trọng lượng kim loại nhiều hơn so với dầu diesel. Sự hao tổn trọng lượng này tỷ lệ theo thời gian ngâm tĩnh trong hỗn hợp nhiên liệu và tăng theo tỷ lệ phần trăm của nhiên liệu diesel sinh học. Tuy nhiên, sự hao tổn trọng lượng do nhiên liệu diesel sinh học gây ra không quá lớn. Kim loại bị ăn mòn nhiều nhất là đồng, tiếp theo là hợp kim đồng, nhôm, hợp kim nhôm, thép và hợp kim thép.

    The genetic polymorphisms of 15 autosomal short tandem repeat (STR) loci were analyzedfrom 110 unrelated healthy individuals of Khmer population living in Soc Trang Province ofVietnam using a multiplex PCR system which had been published in our recent researchresults. Separation of PCR products was carried out on the 3130 Genetic Analyzer (AppliedBiosystems, Foster City, CA, USA) together with Internal Lane Standard 600 (Promega,DG1071). Data were analyzed by GeneMapper® ID software v 3.2.1 (Applied Biosystems,Foster City, CA), according to the manufacturer's instructions. Allele frequencies andstatistical parameters for 15 studied loci (D3S1358, TH01, D21S11, D18S11, PentaE,D5S818, D13S313, D7S820, D16S359, CSF1PO, PentaD, vWA, D8S1179, TPOX and FGA)were calculated by EasyDNA_PopuData software which is developed by Wing K. Fung, Yue-Qing Hu and Hong Lee, The University of Hong Kong. The observed heterozygosity (OH)values of these 15 STR loci ranged from 0.600 (TPOX) to 0.864 (D18S51). The expectedheterozygosity (EH) ranged from 0.611 (TPOX) to 0.873 (FGA). The power of discrimination(PD) values were found ranging from 0.801 (TPOX) to 0.972 (FGA) and the probability ofexcluding (PE) a random man from paternity varies between 0.325 (TPOX) and 0.749 (PentaE). The p-value of the exact test under Hardy-Weinberg equilibrium of the locus (P1) was153determined to range from 0.115 (D21S11) to 0.985 (D18S51). The agreement with Hardy-Weinberg equilibrium (HWE) was confirmed for 15 studied loci (based on the χ2-test only).For the 15 this studied loci, the combined power of discrimination (CPD) and the combinedpower of exclusion (CPE) are 0,999999999999999995 and 0.9999991, respectively, provingsuitable for the forensic and paternity testing requirements of the Khmer population living inSoc Trang Province of Vietnam.Keywords: STR; Khmer population data; Genetic polymorphisms.

Bee honey is the most well-known and economically important. Honey has long been used as a home remedy to treat coughs and colds for children. Honey diversity is due to many diverse origins. Properties and compositions of bee honey depend strongly on the type of flowers the bees visited, season, on the climatic conditions in which the plants grow and treatment of beekeepers. The aim of this study was to classify honey samples in Vietnam using 1H-NMR data combined multivariate statistics (PCA, SIMCA, kNN, LDA and PLS-DA) methods. The similar results of origin classification of un-known eight honey samples by four multivariate statistics methods were obtained and proved the accurate applied methods. The results can help market managers and companies control the origin of honey samples in Vietnam.