Disclosure of Environmental Information by Manufacturing Firms Listed on the Ho Chi Minh City Stock Exchange (HOSE)

Duong,Hoang Ngoc Khue,Nguyen,Thi Ngoc Oanh 한국유통과학회 2019 KODISA ICBE (International Conference on Business Vol.2019 No.-

This purpose of the study is to evaluate the level of the environmental information disclosures by manufacturing firms which practices the annual reports in accordance with the circular 155/BTC, circular on guidelines for information disclosure on securities market. A model including 16 indexes based on the Circular 155/BTC was used to measure the level of environmental information disclosure. The study has been conducted on the sample of 40 manufacturing firms listed on HOSE and 120 annual reports from year 2014 to 2016 have been used for the study. The findings show that (i) There was an increase in the level of environmental disclosures from 2014 to 2016, and (ii) The extent of environment information disclosure in 2016 is just under average (36.87%). Through the findings several implications are suggested to enhance the level of the environmental information disclosure of firms listed on HOSE.

Some characters of bacterial cellulases in goats' rumen elucidated by metagenomic DNA analysis and the role of fibronectin 3 module for endoglucanase function

Nguyen, Khanh Hoang Viet,Dao, Trong Khoa,Nguyen, Hong Duong,Nguyen, Khanh Hai,Nguyen, Thi Quy,Nguyen, Thuy Tien,Nguyen, Thi Mai Phuong,Truong, Nam Hai,Do, Thi Huyen Asian Australasian Association of Animal Productio 2021 Animal Bioscience Vol.34 No.5

Objective: Fibronectin 3 (FN3) and immunoglobulin like modules (Ig) are usually collocated beside modular cellulase catalytic domains. However, very few researches have investigated the role of these modules. In a previous study, we have sequenced and analyzed bacterial metagenomic DNA in Vietnamese goats' rumen and found that cellulase-producing bacteria and cellulase families were dominant. In this study, the properties of modular cellulases and the role of a FN3 in unique endoglucanase belonging to glycosyl hydorlase (GH) family 5 were determined. Methods: Based on Pfam analysis, the cellulases sequences containing FN3, Ig modules were extracted from 297 complete open reading frames (ORFs). The alkaline, thermostability, tertiary structure of deduced enzymes were predicted by AcalPred, TBI software, Phyre2 and Swiss models. Then, whole and truncated forms of a selected gene were expressed in Escherichia coli and purified by His-tag affinity column for assessment of FN3 ability to enhance enzyme activity, solubility and conformation. Results: From 297 complete ORFs coding for cellulases, 148 sequences containing FN3, Ig were identified. Mostly FN3 appeared in 90.9% beta-glucosidases belonging to glycosyl hydrolase family 3 (GH3) and situated downstream of catalytic domains. The Ig was found upstream of 100% endoglucanase GH9. Rarely FN3 was seen to be situated downstream of X domain and upstream of catalytic domain endoglucanase GH5. Whole enzyme (called XFN3GH5 based on modular structure) and truncate forms FN3, XFN3, FN3GH5, GH5 were cloned in pET22b (+) and pET22SUMO to be expressed in single and fusion forms with a small ubiquitin-related modifier partner (S). The FN3, SFN3 increased GH5 solubility in FN3GH5, SFN3GH5. The SFN3 partly served for GH5 conformation in SFN3GH5, increased modules interaction and enzyme-soluble substrate affinity to enhance SXFN3GH5, SFN3GH5 activities in mixtures. Both SFN3 and SXFN3 did not anchor enzyme on filter paper but exfoliate and separate cellulose chains on filter paper for enzyme hydrolysis. Conclusion: Based on these findings, the presence of FN3 module in certain cellulases was confirmed and it assisted for enzyme conformation and activity in both soluble and insoluble substrate.

A two-step design of experiments approach to investigate the simultaneous effects of ion-pairing and chemical enhancers to improve the permeability of lornoxicam in a topical hydrogel patch

Nguyen Huu-Manh,Duong The-Khang,Nguyen Van-Khuyen,Nguyen Thi-Khanh-Ly,Dong Thi-Hoang-Yen,Nguyen Canh-Hung,Tung Nguyen-Thach 한국약제학회 2024 Journal of Pharmaceutical Investigation Vol.54 No.2

Purpose A two-step experimental design was used to develop a lornoxicam (LOR)-loaded topical hydrogel patch. We specifically focused on the simultaneous effect of the ion pair formation agent (triethanolamine [TEA]) and the chemical enhancer (cremophor RH40 [RH40]) on flux and conducted physicochemical studies and skin physiology assessments to obtain further information. Methods Drug-in-adhesive patches were fabricated using a micrometer-adjustable film applicator. The applied Design of Experiments (DoE) approach consisted of the Fractional Factorial Resolution V + design and the Central Composite Face design established by the MODDE® 12.0 software. Molecular-level drug-excipient interactions were investigated using infrared (IR) and proton nuclear magnetic resonance (1H NMR) spectroscopy. The effects on skin physiological function was assessed using DermaLab Combo. Results DoE results revealed that TEA enhanced flux by 3.14-fold, whereas RH40 reduced it by 4.62-fold. The addition of RH40 resulted in the disappearance of the proton peak within the region of 12–13 ppm, suggesting competition for hydrogen bonding with LOR between TEA and RH40. The optimized formulation (4% TEA, 0% RH40, and 0.2% Al(OH)3) increased skin hydration by 6.20-fold. Opposing effects of TEA and RH40 on skin elasticity were observed. Conclusion Expected flux and adhesion strength for the optimized formulation were 7.18 μg·cm–2·h–1 and 11.79 mJ, respectively. Our understanding of the conflicting effects of TEA and RH40 has been advanced. The integrated use of the two-step DoE, physicochemical studies, and skin physiology assessments was proven to be effective in elucidating the simultaneous effects of different permeation-modifying strategies on patches, thus having substantial value for the successful execution of future research endeavors.

Composites derived from synthetic clay and carbon sphere: Preparation, characterization, and application for dye decontamination

Nguyen Duy Dat,Ton That Loc,Mai Thuan Trieu,Dong Thanh Nguyen,Khuong Quoc Nguyen,My Linh Nguyen,Anh Duy Duong Le,Hai Nguyen Tran 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.4

Two new composites from synthetic clay-like materials and carbon spheres were developed. Layered doubledhydroxides (LDH) were synthesized from the coprecipitation of Mg2+ and Al3+ ions. Spherical hydrochar (SH) wasprepared from pure glucose through hydrothermal carbonization at 190 oC. The composite LDH–SH was synthesizedthrough a simple hydrothermal method of the mixture of LDH and SH. Another composite, LDO-SB, was directly preparedthrough the carbonization of LDH-SH at 500 oC. Under such high temperature, LDH was converted to layereddoubled oxides (LDO), and SH was transferred to spherical biochar (SB). Those materials were characterized by chemicalstability, surface morphology and element composition, crystal structure, surface functional group, and texturalcharacteristic. They were applied for removing cationic dye (methylene blue; MB) and anionic dye (Congo red; CR)under different pH solutions. Three adsorption components—kinetics, isotherm, and thermodynamics—were conductedunder batch experimenters. Results demonstrated that the LDH or LDO particles were assembled on the surfaceof SH or SB, respectively. The surface area, total pore volume, and average pore width of LDH–SH and LDO-SBwere 58.5 and 198m2/g, 0.319 and 0.440 cm3/g, and 21.8 and 8.89 nm, respectively. The maximum adsorption capacityof the materials, calculated from the Langmuir model, at 30 oC for CR and MB dyes was 1589 and 78.6mg/g (LDOSB)and 499 and 226mg/g (LDH-SH), respectively. The composites exhibited a higher affinity to anionic than cationicdyes, which resulted from the great contribution of the clay-like materials. Therefore, they can serve as a promisingcomposite for the decolorization of wastewater.

Facile synthesis of ZnBi2O4-graphite composites as highly active visible-light photocatalyst for the mineralization of rhodamine B

Nguyen Thi Mai Tho,Bui The Huy,Dang Nguyen Nha Khanh,Ho Nguyen Nhat Ha,Vu Quang Huy,Ngo Thi Tuong Vy,Do Manh Huy,Duong Phuoc Dat,Nguyen Thi Kim Phuong 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.12

Novel highly active visible-light photocatalysts in the form of zinc bismuth oxide (ZnBi2O4) and graphite hybrid composites were prepared by coupling via a co-precipitation method followed by calcination at 450 oC. The asprepared ZnBi2O4-graphite hybrid composites were tested for the degradation of rhodamine B (RhB) solutions under visible-light irradiation. The existence of strong electronic coupling between the two components within the ZnBi2O4- graphite heterostructure suppressed the photogenerated recombination of electrons and holes to a remarkable extent. The prepared composite exhibited excellent photocatalytic activity, leading to more than 93% of RhB degradation at an initial concentration of 50mg·L1 with 1.0 g catalyst per liter in 150min. The excellent visible-light photocatalytic mineralization of ZnBi2O4-1.0graphite in comparison with pristine ZnBi2O4 could be attributed to synergetic effects, charge transfer between ZnBi2O4 and graphite, and the separation efficiency of the photogenerated electrons and holes. The photo-induced h+ and the superoxide anion were the major active species responsible for the photodegradation process. The results demonstrate the feasibility of ZnBi2O4-1.0graphite as a potential heterogeneous photocatalyst for environmental remediation.

Enhancing Charge Injection of PEDOT:PSS-based Organic Photovoltaics by Incorporation of N-doped Carbon Quantum Dots

Nguyen Duong Nguyen,김정규,이준영 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.2

The utilization of a nitrogen-doped carbon quantum dot (N-CQD)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) composite as a hole transport layer (HTL) in bulk heterojunction organic photovoltaic devices (OPVs) is demonstrated. Because of the electrostatic interaction between N-CQDs and the polymers, the reorientation of PEDOT chains and the interconnected structure of PEDOT-rich domains are readily formed. Consequently, the incorporation of N-CQD in PEDOT:PSS layer leads to a significant increase in electrical conductivity and smother surface. The power conversion efficiency (PCE) of the OPV device using N-CQDs/PEDOT:PSS as the HTL was 17% higher than the device with pristine PEDOT-PSS with/without oxidized carbon quantum dot (O-CQD) as the HTL with a VOC of 0.74 V, a JSC of 17.2 mA/cm², and a FF of 66.63%. Our results indicate that N-CQD could be a simple supplementation to PEDOT:PSS as the effective hole transport layer in OPV devices.

MBE growth and magnetic properties of epitaxial FeMn2O4 film on MgO(100)

Duong Van Thiet,Nguyen Thi Minh Hai,Nguyen Anh Phuong,Dang Duc Dung,Duong Anh Tuan,Nguyen Van Quang,Sunglae Cho 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.2

Antibiotic-Resistant Gram-negative Bacteria Carriage in Healthcare Workers Working in an Intensive Care Unit

Duong Bich Thuy,Duong Minh Cuong,Campbell James,Nguyen Van Minh Hoang,Nguyen Huu Hien,Bui Thi Bich Hanh,Nguyen Van Vinh Chau,McLaws Mary-Louise 대한감염학회 2021 Infection and Chemotherapy Vol.53 No.3

Little is known about antibiotic-resistant Gram-negative bacteria (GNB) intestinal carriage among healthcare workers (HCWs) in Vietnam. All HCWs at a tertiary intensive care units were asked to undertake weekly rectal swabs. Among 40 participants, 65% (26/40) carried extended spectrum β-lactamases (ESBL)/AmpC β-lactamase-producing Escherichia coli. Two HCWs colonized with ESBL/AmpC β-lactamase-producing Klebsiella pneumoniae. One HCW colonized with Acinetobacter baumannii. No one carried Pseudomonas spp.. A quarter (10/40) of HCWs were identified as persistent and frequent carriers. There is an urgent need to screen antibiotic-resistant GNB among HCWs and improve HCWs’ hand hygiene compliance to reduce the transmission of antibiotic-resistant GNB in the hospital.

Large Magnetocaloric Effect above 300 K and Magnetoresistance in (La0.5Pr0.5)1-xPbxMnO3 Perovskites

Nguyen Chau,Duong Thi Hanh,Bui Cong Tinh,Nguyen Hoang Luong,Nguyen Duc Tho,Nguyen Hoang Hai 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5

Perovskite compounds (La0.5Pr0.5)₁- xPbxMnO₃ (x = 0.1 - 0.5) with orthorhombic structure were prepared by using a solid-state reaction technique. In the studied samples, the spin-glass-like state occurs at low temperatures and the Curie temperature, Tc, increases from 170 K (x = 0.1) to 336 K (x = 0.5) because of a strong double exchange. The magnetic entropy change, │△Sm│, reached its largest value of 2.06 J/kg·K at △H = 13.5 kOe for the sample with x = 0.4 (Tc = 323 K). Due to the large │△Sm│ and high Tc, these materials are suggested for use as active magnetic refrigerants for magnetic refrigeration technology at temperatures above room temperature. While the conductivity of the samples with x = 0.1 and 0.2 exhibits only a semiconducting behavior over the whole measured temperature range, there is insulator-metallic phase transition on the R(T) curves of the samples with x = 0.3 - 0.5. The magnetoresistance of the samples was measured and large values for MR were found. Perovskite compounds (La0.5Pr0.5)₁- xPbxMnO₃ (x = 0.1 - 0.5) with orthorhombic structure were prepared by using a solid-state reaction technique. In the studied samples, the spin-glass-like state occurs at low temperatures and the Curie temperature, Tc, increases from 170 K (x = 0.1) to 336 K (x = 0.5) because of a strong double exchange. The magnetic entropy change, │△Sm│, reached its largest value of 2.06 J/kg·K at △H = 13.5 kOe for the sample with x = 0.4 (Tc = 323 K). Due to the large │△Sm│ and high Tc, these materials are suggested for use as active magnetic refrigerants for magnetic refrigeration technology at temperatures above room temperature. While the conductivity of the samples with x = 0.1 and 0.2 exhibits only a semiconducting behavior over the whole measured temperature range, there is insulator-metallic phase transition on the R(T) curves of the samples with x = 0.3 - 0.5. The magnetoresistance of the samples was measured and large values for MR were found.

Lanostane Triterpenoids from Ganoderma tropicum Collected in Vietnam and Their Nitroblue Tetrazolium Reductive Activity In Vitro

Nguyen Thi Duyen,Nguyen Minh Khoi,Phan Nguyen Truong Thang,Duong Minh Tan,Tran Viet Hung,Do Thi Ha 한국생약학회 2020 Natural Product Sciences Vol.26 No.4

A new compound, 3β-acetoxylanosta-7,9(11),24-triene-26-al (3), and seven known compounds (1 – 2 and 4 – 8) were isolated from Ganoderma tropicum (Jung.) Bres. collected in Tay Nguyen, Vietnam. The structures of these compounds were determined by one- and two-dimensional nuclear magnetic resonance spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and high-resolution ESI-MS, and by comparison with literature data. All of the isolated compounds were tested for nitroblue tetrazolium (NBT) reduction activity in Saccharomyces cerevisiae-stimulated RAW 246.7 cells. Among them, compounds 2 – 4 and 6 – 8 enhanced the NBT reduction in a dose-dependent manner.