pH-Dependence of the Optical Bio-sensor Based on DNA-carbon Nanotube

In 2006, Daniel A. Heller et al. [1] demonstrated that carbon nanotubes (CNNTs) wrapped with DNA can be placed inside living cells and detect trace amounts of harmful contaminants using near infrared light. This discovery could lead to new types of optical sensors and biomarkers at the sub cellular level. The working principle of this optical bio-sensor from DNA and CNNTs can be explained by a simple theoretical model which was introduced in [3]. In this paper, the pH-dependence of DNA and the pH-dependence of solution around CNNTs are shown by using data analysis method. By substituting them into the same model, the pH-dependence of DNA-wrapped CNNTs was elicited in this paper. The range of parameters for workable conditions of this bio-sensor was indicated that the solution should have pH from 6 to 9 and the concentration of ions should be more than a critical value. These results are according to the experimental data and the deduction about pH and salt concentration in solution. They are very useful as using such a new bio-sensor like this in living environment

Van Der Waals and Casimir Interactions of Some Graphene, Material Plate and CNTs Systems

The Van der Waals and Casimir interactions between graphene and a material plate are studied by using the Lifshitz theory and approximate expressions for the free energy and force. The reflection properties of electromagnetic oscillations on graphene are governed by specific boundary conditions imposed on the infinitely thin positively charged plasma sheet, carrying a continuous fluid with some mass and charge density. The obtained formulas are applied to the cases of a graphene interacting with Au plate. We calculated also the Casimir interaction between carbon nanotube single wall and Au plate. The comparision with other recently obtained theoretical results are made and the generalizations to more complicated carbon nanostructures are discussed

Assessment of aflatoxin B1 contamination in rice and maize

Introduction: Aflatoxins B1 are among the most common poisonous mycotoxins produced by certain fungi that harm animals and crops. Mycotoxins can cause a variety of adverse health effects and pose a serious health threat to humans. The Maximum Residue Limits of aflatoxin B1 in processed cereals and ingredients are 2 parts per billion (ppb) and 5 ppb, respectively. Objectives: To evaluate the status of aflatoxin B 1 contamination in rice, corn and staple food produced in Ha Giang province compared with the maximum permitted levels. Methods: A total of 210 rice and maize samples were analyzed to quantify the level of aflatoxin B1. Analysis of mycotoxins was conducted by High Performance Liquid Chromatography using a fluorescence detector. Results: It was found that rice, rice products, maize, and maize products had a mean aflatoxin B1 content of 1.79 ppb, 2.55 ppb, 2.19 ppb, and 6.35 ppb, respectively. The results also showed that 71.9% of samples were contaminated with mycotoxins, and 14.28% of samples exceeded the maximum allowable limit. Conclusion: The concentration of aflatoxin B1 in 14.28% of the samples are over permissible limits by nationwide regulations

In silico analysis of hypermethylation in CpGislands of UCHL1 gene’s promoter in nasopharyngeal carcinoma

Background and Objective: The methylation of Ubiquitin C-Terminal Hydrolase L1 (UCHL1) gene has been reported in many human cancers including nasopharyngeal carcinoma (NPC). In Vietnam, the methylation of UCHL1 gene’s promoter in NPC has not been demonstrated yet. In this study, a systematic literature revision was carried out to summarize the current evidences about the frequencies of UCHL-1 gene’s promoter methylation in NPC for further application in Vietnamese population. Methods: A systematic literature analysis was conducted based on the comprehensive studies. Moreover, many bioinformatic tools such as Methprimer, TFsearch, IDT OligoAnalyzer 3.1 were used to predict the CpG islands, transcriptional factors, and to pick up the MSP (Methylation-Specific PCR) primers. Results: Total of three previous studies were summarized and accessed for eligibility from literature research. As the results, the average weight methylated frequencies were 72.4% and 13.0% for NPC and non-cancerous samples, respectively. The significant association between UCHL-1 promoter methylation and NPC with the OR of 10.459 (95% CI = 4.915 – 22.254, p < 0.001) and RR of 4.117 (95% CI = 1.958 – 6.645, p < 0.0001) based on the random effects model, was observed. Moreover, we were successful in predicting the CpG islands as well as identifying transcriptional factor binding sites which served as “hot spot” for ideal primer pick up and located in gene promoter. Conclusion: The methylation of UCHL-1 gene promoter was significantly associated and contributed to NPC developmentin which it could be further applied in evaluation of UCHL-1 gene promoter status in Vietnamese population

Evaluation of EBNA-1 (epstein-barr virus nuclear antigen-1) gene prevalence in nasopharyngeal carcinoma in Vietnamese patients

This study examined the presence of Epstein-Barr virus (EBV) in nasopharyngeal carcinoma (NPC) based on the detection of EBNA-1 (Epstein-Barr virus nuclear antigen-1) by Polymerase Chain Reaction (PCR), in Vietnamese population. Firstly, we systematically analyzed the mean of percentage weighted of the presence of EBNA-1 in previous relevant studies. Experimentally, 31 nasopharyngeal cancer biopsies and 20 healthy samples were enrolled in current to evaluate the frequency of candidate genes. As the results, the frequency of EBNA-1 was 77.42%, whereas, none of any cases of healthy samples were found to positive to target gene. The p value < 0.05 (p = 0.0001) showed that it was significant correlation between the presence of this candidate gene and nasopharyngeal cancer. Moreover, a high odds ratio (OR) and relative risk (RR) of candidate gene, (OR = 68.16, RR = 2.41) were calculated. Therefore, the detection of EBNA-1, which performed by PCR, could serve as a good supplement to early diagnosis and prognosis of NPC in Vietnamese population