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Does conventional freezing affect sperm DNA fragmentation?
Le, Minh Tam,Nguyen, Thai Thanh Thi,Nguyen, Tung Thanh,Nguyen, Trung Van,Nguyen, Tam An Thi,Nguyen, Quoc Huy Vu,Cao, Thanh Ngoc The Korean Society for Reproductive Medicine 2019 Clinical and Experimental Reproductive Medicine Vol.46 No.2
Objective: Sperm cryopreservation has been widely used in assisted reproductive technology, as it offers great potential for the treatment of some types of male infertility. However, cryopreservation may result in changes in membrane lipid composition and acrosome status, as well as reductions in sperm motility and viability. This study aimed to evaluate sperm DNA fragmentation damage caused by conventional freezing using the sperm chromatin dispersion test. Methods: In total, 120 fresh human semen samples were frozen by conventional methods, using SpermFreeze Solution as a cryoprotectant. Routine semen analysis and a Halosperm test (using the Halosperm kit) were performed on each sample before freezing and after thawing. Semen parameters and sperm DNA fragmentation were compared between these groups. Results: There was a significant decrease in sperm progressive motility, viability, and normal morphology after conventional freezing (32.78%, 79.58%, and 3.87% vs. 16%, 55.99%, and 2.55%, respectively). The sperm head, midpiece, and tail defect rate increased slightly after freezing. Furthermore, the DNA fragmentation index (DFI) was significantly higher after thawing than before freezing (19.21% prior to freezing vs. 22.23% after thawing). Significant increases in the DFI after cryopreservation were observed in samples with both normal and abnormal motility and morphology, as well as in those with normal viability. Conclusion: Conventional freezing seems to damage some sperm parameters, in particular causing a reduction in sperm DNA integrity.
The Adoption of Risk Based Audit Approach in the Independent Audit Firms: A Study of Case of Vietnam
LE, Thi Tam,NGUYEN, Thi Mai Anh Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.2
This study was conducted to examine how independent audit firms in Vietnam understand and use risk based audit approach (RBAA) in audit practice. To answer the research questions, the researchers used primary and secondary data collected from 2018 to 2019. The results from the interview survey showed that audit firms were aware of the advantages of adopting RBAA. However, RBAA is practiced to a moderate extent by audit firms in Vietnam. Big 4 audit firms use RBAA more popularly than Non-Big 4 audit firms. The causes of the difference are the disadvantages of adopting RBAA and client's characteristics such as relevant guideline, audit fees, auditors' knowledge and experience. Besides, the study investigated factors impacting on the RBAA adoption by distributing a questionnaire to 246 auditors of 126 audit firms in Vietnam. A set of statistical appropriate methods where used through SPSS software version 22.0. The results indicated that there were six factors influencing RBAA adoption including: Auditor's ability, Technological development, Audit fees, auditors' motivation, Audit time and client's risk. Of which, auditor's ability and technological development are factors that have the most significant and positive impacts on the adoption of RBAA. Additional implications were argued in the final section of this study.
Le, Minh Tam,Nguyen, Thi Tam An,Nguyen, Thi Thai Thanh,Nguyen, Van Trung,Le, Dinh Duong,Nguyen, Vu Quoc Huy,Cao, Ngoc Thanh,Aints, Alar,Salumets, Andres The Korean Society for Reproductive Medicine 2018 Clinical and Experimental Reproductive Medicine Vol.45 No.3
Objective: In frozen and thawed embryos, the zona pellucida (ZP) can be damaged due to hardening. Laser-assisted hatching (LAH) of embryos can increase the pregnancy rate. This study compared thinning and drilling of the ZP before frozen embryo transfer (FET). Methods: Patients were randomly allocated into two groups for LAH using thinning or drilling on day 2 after thawing. Twenty-five percent of the ZP circumference and 50% of the ZP thickness was removed in the thinning group, and a hole $40{\mu}m$ in diameter was made in the drilling group. Results: A total of 171 in vitro fertilization/intracytoplasmic sperm injection FET cycles, including 85 cycles with drilling LAH and 86 cycles with thinning LAH, were carried out. The thinning group had a similar ${\beta}$-human chorionic gonadotropin-positive rate (38.4% vs. 29.4%), implantation rate (16.5% vs. 14.4%), clinical pregnancy rate (36.0% vs. 25.9%), miscarriage rate (5.8% vs. 2.4%), ongoing pregnancy rate (30.2% vs. 23.5%), and multiple pregnancy rate (7.0% vs. 10.6%) to the drilling LAH group. There were no significant differences in pregnancy outcomes between subgroups defined based on age (older or younger than 35 years) or ZP thickness (greater or less than $17{\mu}m$) according to the LAH method. Conclusion: The present study demonstrated that partial ZP thinning or drilling resulted in similar outcomes in implantation and pregnancy rates using thawed embryos, irrespective of women's age or ZP thickness.
Determinants of Operational Self-Sustainability of Microfinance Institutions in Vietnam
LE, Thanh Tam,DAO, Lan Phuong,DO, Ngoc Mai,TRUONG, Thi Hoai Linh,NGUYEN, Thi Thuy Duong,TRAN, Chung Thuy Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.10
The purpose of this paper is to investigate the determinants of the Operational Self-Sustainability (OSS) of Vietnamese microfinance institutions (MFIs). This research uses both qualitative and quantitative research methods: (i) qualitative research was via in-depth interviews with ten microfinance practitioners, policymakers and researchers; (ii) quantitative research was conducted by using panel data of 34 MFIs in the period 2011-2015 with binary logistics and OLS regressions. Results are as follows: (i) MFIs' OSS in Vietnam are mainly determined by five key factors: portfolio at risk (PAR>30), capital structure, gross loan portfolio, scope of activities and legal form; (ii) OSS are most affected by legal status (social organizations have better OSS than formal MFIs or programs/projects), location (MFIs focus in one province have higher OSS than working nationwide or just in one district), capital structure (MFIs with more equity proportion have higher OSS); (iii) surprisingly, average loan size per borrower and age of MFIs do not have statistically significant correlation with OSS. The key recommendations are: (i) MFIs should focus on its professionality and increase its equity; (ii) related stakeholders such as State Bank of Vietnam should promote the enabling ecosystem for microfinance development to enhance poverty reduction and economic development.
Green and low-cost preparation of CIGSe thin film by a nanocrystals ink based spin-coating method
Trang Thi Thuy Le,Nam Le,Mohan Reddy Pallavolu,전윤창,정동섭,Babu Pejjai,Vasudeva Reddy Minnam Reddy,Nguyen Tam Nguyen Truong,박진호 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.12
An “ink” solution based process, using spin-coating technique, followed by annealing in selenium environment with different temperature programs was utilized to prepare CIGSe thin films. Herein, the CuIn0.7Ga0.3Se2 nanocrystals were synthesized using ethanol - a “green” solvent. Three different solvents: 2-propanol, 2-methoxyethanol, and their 2:1 mixture (v/v ratio), were investigated as a dispersion medium for the as-synthesized CIGSe nanocrystals to form a stable ink solution. The last one- a mixture of 2-propanol:2-methoxyethanol=2:1 (v/v), was found to be the most suitable. Furthermore, the influences of various annealing modes on the CIGSe grain size and density in the resulting film were also studied. The as-prepared CIGSe thin film was around 1µm thick and possessed a tetragonal structure. A newly developed cheaper and “greener” non-vacuum process was applied successfully from the synthesis of nanocrystals to the formation of ink solution, and produced high quality thin films; this opens a new route to the cost-competitive commercialization of CIGSe thin film solar cells.
Luong Thi Tham,Nguyen Thi Hong Tham,Nguyen Tien Dat,Le Van Toan,Pham Thi Hong Trang,Ho Thanh-Tam,Nguyen Ngoc-Loi 한국미생물·생명공학회 2024 Journal of microbiology and biotechnology Vol.34 No.1
The widespread application of triazole fungicides (TFs) in agricultural practices can result in the considerable accumulation of active compound residues in the soil and a subsequent negative impact on the soil microbiota and crop health. In this study, we isolated three TF-degrading bacterial strains from contaminated agricultural soils and identified them as Klebsiella sp., Pseudomonas sp., and Citrobacter sp. based on analysis of morphological characteristics and 16S rRNA gene sequences. The strains used three common TFs, namely hexaconazole, difenoconazole, and propiconazole, as their only sources of carbon and energy for growth in a liquid mineral salt medium, with high concentrations (~ 500 mg/l) of each TF. In addition to the ability to degrade fungicides, the isolates also exhibited plant growth-promoting characteristics, such as nitrogen fixation, indole acetic acid production, phosphate dissolution, and cellulose degradation. The synergistic combination of three bacterial isolates significantly improved plant growth and development with an increased survival rate (57%), and achieved TF degradation ranging from 85.83 to 96.59% at a concentration of approximately 50 mg/kg of each TF within 45 days in the soil-plant system. Based on these findings, the three strains and their microbial consortium show promise for application in biofertilizers, to improve soil health and facilitate optimal plant growth.
Nguyen Thi Thuy,Phuong Dinh Tam,Mai Anh Tuan,Anh-Tuan Le,Le Thi Tam,Vu Van Thu,Nguyen Van Hieu,Nguyen Duc Chien 한국물리학회 2012 Current Applied Physics Vol.12 No.6
The present paper introduces a facile and cost-effective route for the direct dispersion of multi-walled carbon nanotubes (MWCNTs) in DNA solution. Their application in detecting Escherichia coli O157:H7using DNA biosensorwas demonstrated. The dispersion state of theMWCNTswas characterized via UVeVis spectroscopy, transmission electron microscopy, and field emission scanning electron microscopy. The interaction between DNA sequence and the MWCNTs was investigated using Raman spectroscopy and Fourier transform infrared spectroscopy. As-obtainedMWCNT solutionwas used in the preparation of DNA sensor. Results revealed that the developed DNA sensor can detect a DNA target as low as 1 nM in a buffer solution. The sensitivity of the DNA sensor reached approximately 0.19 nM/mV. The effect of dispersion parameters, including pH values, DNA concentration, ion strength, and sonication time, on sensor response was also studied. TheDNA sensor can respondwell to 120 min of sonication time, a pH value of 9, and 20 mM of DNA sequence concentration. The results of the present study showed a potential application of the DNA sensor in the detection of Escherichia coli O157:H7.
Minh Tam Le,Hiep Tuyet Thi Nguyen,Trung Van Nguyen,Thai Thanh Thi Nguyen,Hong Nhan Thi Dang,Thuan Cong Dang,Quoc Huy Vu Nguyen The Korean Society for Reproductive Medicine 2023 Clinical and Experimental Reproductive Medicine Vol.50 No.2
Objective: This study aimed to compare the efficacy of physiological intracytoplasmic sperm injection (PICSI) and intracytoplasmic sperm injection (ICSI) in terms of the fertilization rate and embryo quality using sibling oocyte cycles. Methods: This prospective, cross-sectional study collected data from 76 couples who underwent their first cycle at the Hue Center for Reproductive Endocrinology and Infertility, Vietnam, between May 2019 and November 2021. The inclusion criteria were cycles with at least eight oocytes and a sperm concentration of 5×10<sup>6</sup>/mL. Sperm parameters, sperm DNA fragmentation (SDF), fertilization, and the quality of cleavage-stage embryos on day 2 and blastocysts on day 5 were examined. Results: From 76 ICSI cycles, 1,196 metaphase II (MII) oocytes were retrieved, half of which were randomly allocated to either the PICSI (n=592) or ICSI (n=604) treatment group. The results showed no significant difference between the two groups in terms of fertilization (72.80% vs. 75.33%, p=0.32), day 2 cleavage rate (95.13% vs. 96.04%, p=0.51), blastulation rate (52.68% vs. 57.89%), and high-quality blastocyst rate (26.10% vs. 31.13%, p=0.13). However, in cases where SDF was low, 59 cycles consisting of 913 MII oocytes produced a considerably higher blastulation rate with PICSI than with ICSI (50.49% vs. 35.65%, p=0.00). There were no significant differences between the pregnancy outcomes of the PICSI and ICSI embryo groups following embryo transfer. Conclusion: Using variable sperm quality provided no benefit for PICSI versus ICSI in terms of embryo outcomes. When SDF is low, PICSI appears to be able to produce more blastocysts.
Determinants Influencing Tax Compliance: The Case of Vietnam
NGUYEN, Thi Thuy Du'o'ng,PHAM, Thi My Linh,LE, Thanh Tam,TRUONG, Thi Hoai Linh,TRAN, Manh Dung Korea Distribution Science Association 2020 The Journal of Asian Finance, Economics and Busine Vol.7 No.2
The purpose of this paper is to ascertain the key factors affecting tax compliance among Vietnamese firms in Vietnam. We employ both qualitative and quantitative research methods. Qualitative research has been carried out through focus group discussions with ten chief accountants and tax officers. Quantitative research has been conducted through interviews with 200 firms (chief accountants or financial directors) in Vietnam. Analysis of the model includes the following stages: (i) Cronbach's test for reliability of the scale, (ii) exploratory factor analysis (EFA), (iii) confirmatory factor analysis (CFA), and (iv) structural equation model (SEM). The results of the research show that voluntary tax compliance is directly affected by the three factors of audit probability, corporate reputation and business ownership. The probability of audit and severity of sanctions have the strongest impact on tax compliance. Therefore, the tax authorities need to strengthen the inspection of tax declarations, tax payments and tax refunds of firms. The paper confirms that enforced tax compliance is directly affected by the three factors of audit probability, sanction severity and social norms. Voluntary compliance and compulsory compliance have an effect on tax compliance, though voluntary compliance has a more powerful impact.