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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.
Correlations between abnormalities of morphological details and DNA fragmentation in human sperm
Nguyen, Hiep Tuyet Thi,Dang, Hong Nhan Thi,Nguyen, Thai Thanh Thi,Nguyen, Trung Van,Dang, Thuan Cong,Nguyen, Quoc Huy Vu,Le, Minh Tam The Korean Society for Reproductive Medicine 2022 Clinical and Experimental Reproductive Medicine Vol.49 No.1
Objective: As the associations of sperm DNA fragmentation with morphology have not been examined in detail, this study aimed to investigate the relationship between abnormalities of morphological details and DNA integrity in human sperm. Methods: In this cross-sectional study, men from infertile couples were enrolled at Hue Center for Reproductive Endocrinology and Infertility, Vietnam. Conventional semen parameters, including morphological details, were analyzed following the World Health Organization 2010 criteria. Sperm DNA fragmentation was evaluated using a sperm chromatin dispersion assay. The relationships and correlations between semen parameters, sperm morphology, and the type of halosperm and the DNA fragmentation index (DFI) were analyzed. Results: Among 130 men in infertile couples, statistically significant differences were not found in the sperm halo type between the normal and abnormal sperm morphology groups. The percentage of round-head spermatozoa was higher in the DFI >15% group (16.98%±12.50%) than in the DFI ≤15% group (13.13% ±8.82%), higher values for amorphous heads were found in the DFI >15% group, and lower values for tapered heads were observed in the DFI ≤15% group; however, these differences were not statistically significant. Small-halo sperm and the DFI were positively correlated with round-head sperm (r=0.243, p=0.005 and r=0.197, p=0.025, respectively). Conclusion: The rate of general sperm morphological abnormalities in semen analysis was not related to sperm DNA integrity. However, round sperm heads were closely associated with sperm DNA fragmentation.
Advanced Magnetic Materials Produced by Using Rapid Quenching Technology
Nguyen Hoang Nghi,Nguyen Van Dung,Trinh Thi Thanh Nga,Bui Thi Khanh Nhung,Mai Thanh Tung,Nguyen Huu Tinh,Hoang Nhat Hieu,Bui Xuan Chien,Nguyen Thi Hong Tam 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.6
Amorphous alloys produced by using a rapid quenching technique are considered to be a precursor for producing nanosized and multiphase structures by precipitation (the top-down method). By using this technique, several new magnetic materials with different magnetic properties based on different physical mechanisms have been manufactured and investigated. Three new magnetic materials, a nanocrystalline soft magnetic material, a soft-hard permanent magnet and a Me-3d granular alloy with a GMR effect, what were prepared under local conditions, are presented and discussed in the experimental point of view. Amorphous alloys produced by using a rapid quenching technique are considered to be a precursor for producing nanosized and multiphase structures by precipitation (the top-down method). By using this technique, several new magnetic materials with different magnetic properties based on different physical mechanisms have been manufactured and investigated. Three new magnetic materials, a nanocrystalline soft magnetic material, a soft-hard permanent magnet and a Me-3d granular alloy with a GMR effect, what were prepared under local conditions, are presented and discussed in the experimental point of view.
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.
Enhancement of natural killer cell functions by HongJam
Nguyen Thi Thanh Tam,Phan Trinh Yen Binh,Yoo Hee Kim,Young Ho Koh 한국응용곤충학회 2023 한국응용곤충학회 학술대회논문집 Vol.2023 No.10
Immunity is largely divided into innate immunity and adaptive immunity. We conducted a study using HongJam extract to confirm its innate immunity-enhancing effect. Our data using Natural Killer (NK) cells, which play an important role in innate immunity, confirmed that HongJam extract promotes the proliferation of NK cells and also enhances the function of NK cells to attack and destroy cancer cells. (Grant No. PJ017024022023)
Nhung Thanh Thi Truong,Tam Huu Nguyen,Bao Kim Doan,Le-Thu T. Nguyen,Tam Hoang Luu,Chau Duc Tran,Thiet Quoc Nguyen,Ha Tran Nguyen 한국고분자학회 2021 Macromolecular Research Vol.29 No.11
In this research, three organic photocatalysts, 4-(4H-dithieno[3,2-b:2',3'- d]pyrrol-4-yl)-N,N-diphenylaniline, 4-(pyren-1-yl)-4H-dithieno[3,2-b:2',3'-d]pyrrole and 4-(6b,10-dihydroperylen-3-yl)-4H-dithieno[3,2-b:2',3'-d]pyrrole have been successfully synthesized through C-N coupling reactions. The chemical structures and the optical properties of the obtained organic photocatalysts have been characterized via 1H NMR,13C NMR, elemental analysis, and UV-Vis spectroscopy. Next, these dithieno[3,2-b:2′,3′-d]pyrrole-based photocatalysts have been used for the polymerization of methyl methacrylate, 2-(dimethylamino)ethyl methacrylate and tert-butyl methacrylate monomers under 365 nm UV irradiation, resulting in (meth)acrylate polymers with controlled molecular weights and low polydispersity indexes.
Analyzing the Purity of Carbon Nanotubes by Using Different Methods
Ngo Thi Thanh Tam,Nguyen Xuan Nghia,Nguyen The Quynh,Phan Hong Khoi,Phan Ngoc Minh 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5
The purity of carbon nanotubes (CNTs) was evaluated by using a variety of methods: X-ray diraction, Raman spectroscopy, thermogravimetric analysis and energy dispersive X-ray uores- cence spectroscopy. X-ray diffraction, Raman spectroscopy and thermogravimetric analysis were used for a qualitative evaluation of impurities and energy dispersive X-ray uorescence spectroscopy was utilized for a quantitative determination. All experimental results evaluating the purity ob- tained from these techniques are consistent with each other for CNT samples with different degrees of purity. The purity of the CNT samples was found to be greatly increased when they were annealed in air or in vacuum. The contributions of Si-related, crystalline carbon, non-crystalline carbon and Fe and Ni components are discussed. The purity of carbon nanotubes (CNTs) was evaluated by using a variety of methods: X-ray diraction, Raman spectroscopy, thermogravimetric analysis and energy dispersive X-ray uores- cence spectroscopy. X-ray diffraction, Raman spectroscopy and thermogravimetric analysis were used for a qualitative evaluation of impurities and energy dispersive X-ray uorescence spectroscopy was utilized for a quantitative determination. All experimental results evaluating the purity ob- tained from these techniques are consistent with each other for CNT samples with different degrees of purity. The purity of the CNT samples was found to be greatly increased when they were annealed in air or in vacuum. The contributions of Si-related, crystalline carbon, non-crystalline carbon and Fe and Ni components are discussed.
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.