Enhancement of the giant magnetoimpedance effect and its magnetic response in ion-irradiated magnetic amorphous ribbons

Le, A.T.,Hoa, N.Q.,Tam, P.D.,Park, D.G.,Phan, M.H.,Srikanth, H.,Yu, S.C. Elsevier 2010 Materials science and engineering B. Advanced Func Vol.166 No.1

The influences of N and Xe ion irradiation on the giant magnetoimpedance (GMI) effect and its magnetic response in Co<SUB>69</SUB>Fe<SUB>4.5</SUB>Al<SUB>1.5</SUB>Si<SUB>10</SUB>B<SUB>15</SUB> amorphous ribbons were systematically investigated. A large enhancement of the GMI effect and its magnetic response were achieved in N and Xe ion-irradiated amorphous ribbons. At a frequency of 3MHz, the GMI ratio and magnetic response for an N-ion-irradiated amorphous ribbon respectively reached the highest values of 130% and 13%/Oe, while for a non-irradiated amorphous ribbon they were only about 53% and 8%/Oe. The enhancement of the GMI effect and magnetic response in the ion-irradiated amorphous ribbons resulted from the enhancement of the permeability due to rotational magnetization. Our studies indicate that low energy ion irradiation is useful for improving the magnetic softness, GMI and magnetic response of amorphous alloys, which is of practical importance for the development of high-performance magnetic sensors.

The reproduction potentials of four entomopathogenic nematode strains related to cost-effective production for biological control

Chau Nguyen N.,Anh Le T.,Vu Nguyen H.,Phuc Hoang K. 한국응용곤충학회 2022 Journal of Asia-Pacific Entomology Vol.25 No.2

Bioassays to evaluate the mortality, virulence and reproduction potentials of four indigenous EPN strains, SPQ16, S-BM12, H-KT3987 and H-CB3452 on insect larvae of mealworm (Tenebrio molitor) and greater wax moth (Galleria mellonella) revealed the highest mortality rates of two insect larvae at the highest inoculation dose of 100 IJs to range from 89 to 100 percent and 94.3–100 percent at 48 h after inoculation, respectively. Virulence was high for all nematode strains, with LC 50 values between 29.6 and 47.3 IJs/insect host. The highest IJ yields were different between nematode strains and insect host, from 66.8 × 10 3 IJs (S-PQ16) to 118.6 × 10 3 IJs (HKT3987) on T. molitor, and from 54.2 × 10 3 IJs (S-BM12) to 163.3 × 10 3 IJs (H-KT3987) on G. mellonella. The culturing cost in terms of food expenditure for rearing insect larvae varied between insect larvae and nematode strains, from 6.76 to 26.63 USD per billion IJs for nematode strains cultured on T. molitor larvae and from 3.54 to 7.81 USD per billion IJs for nematode strains cultured on G. mellonella larvae. The full cost for a nematode product of 2.5 × 10 9 IJs per hectare, produced through in vivo mass culturing, of the most efficient nematode strain, H-KT3987, was 191.3 USD, slightly cheaper than 199.4 USD for the same nematode product produced through in vitro mass culturing.

Mixed-Metal Zeolitic Imidazolate Frameworks and their Selective Capture of Wet Carbon Dioxide over Methane

Nguyen, Nhung T. T.,Lo, Tien N. H.,Kim, Jaheon,Nguyen, Huong T. D.,Le, Toan B.,Cordova, Kyle E.,Furukawa, Hiroyasu American Chemical Society 2016 Inorganic Chemistry Vol.55 No.12

<P>A presynthesized, square planar copper imidazole complex, [Cu(imidazole)(4)](NO3)(2), was utilized as a precursor in the synthesis of a new series of zeolitic imidazolate frameworks, termed ZIF-202, -203, and -204. The structures of all three members were solved by single-crystal X-ray diffraction analysis, which revealed ZIF-203 and -204 having successfully integrated square planar units within the backbones of their respective frameworks. As a result of this unit, the structures of both ZIF-203 and -204 were found to adopt unprecedented three-dimensional nets, namely, ntn and thl, respectively. One member of this series, ZIF-204, was demonstrated to be highly porous, exhibit exceptional stability in water, and selectively capture CO2 over CH4 under both dry and wet conditions without any loss in performance over three cycles. Remarkably, the regeneration of ZIF-204 was performed under the mild conditions of flowing a pure N-2 gas through the material at ambient temperature.</P>

Steroid Components of Marine-Derived Fungal Strain Penicillium levitum N33.2 and Their Biological Activities

Chi K. Hoang,Cuong H. Le,Dat T. Nguyen,Hang T. N. Tran,Chinh V. Luu,Huong M. Le,Ha T. H. Tran 한국균학회 2023 Mycobiology Vol.51 No.4

Genus Penicillium comprising the most important and extensively studied fungi has beenwell-known as a rich source of secondary metabolites. Our study aimed to analyze andinvestigate biological activities, including in vitro anti-cancer, anti-inflammatory and anti-diabeticproperties, of metabolites from a marine-derived fungus belonging to P. levitum. Thechemical compounds in the culture broth of P. levitum strain N33.2 were extracted withethyl acetate. Followingly, chemical analysis of the extract leaded to the isolation of threeergostane-type steroid components, namely cerevisterol (1), ergosterol peroxide (2), and(3b,5a,22E)-ergosta-6,8(14),22-triene-3,5-diol (3). Among these, (3) was the most potent cytotoxicagainst human cancer cell lines Hep-G2, A549 and MCF-7 with IC50 values of 2.89,18.51, and 16.47 mg/mL, respectively, while the compound (1) showed no significant effectagainst tested cancer cells. Anti-inflammatory properties of purified compounds were evaluatedbased on NO-production in LPS-induced murine RAW264.7 macrophages. As a result,tested compounds performed diverse inhibitory effects on NO production by the macrophages,with the most significant inhibition rate of 81.37 ± 1.35% at 25 mg/mL by the compound(2). Interestingly, compounds (2) and (3) exhibited inhibitory activities againstpancreatic lipase and a-glucosidase enzymes in vitro assays. Our study brought out newdata concerning the chemical properties and biological activities of isolated steroids from aP. levitum fungus.

Tuning of the Curie Temperature in La1-xSrxMn1-yTiyO₃

N. X. Phuc,N. T. Hieu,N. T. H. Le,D. H. Manh,N. A. Tuan,L. V. Hong,L. T. C. Tuong 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.5

Magnetic nanoparticles of La₁-xSrxMn₁-yTiyO₃ were prepared by using a sol-gel method, followed by annealing at various elevated temperatures. We found that the Curie temperature of the manganite nanoparticles could easily be tuned (from TC ~ 90 ℃ down to ~20 ℃) by substitution of nonmagnetic Ti⁴+ ions (from y = 0 to 7 %) for Mn. A comparison showed that the titanium substitution approach had advantages such as the phase transition being sharper and the magnetization remaining higher than in the case of the earlier known way of TC reduction by decreasing the Sr content from the optimal value of x = 0.3. The new features seem to make La1..xSrxMn₁..yTiyO₃ nanoparticles promising for hyperthermia application. Magnetic nanoparticles of La₁-xSrxMn₁-yTiyO₃ were prepared by using a sol-gel method, followed by annealing at various elevated temperatures. We found that the Curie temperature of the manganite nanoparticles could easily be tuned (from TC ~ 90 ℃ down to ~20 ℃) by substitution of nonmagnetic Ti⁴+ ions (from y = 0 to 7 %) for Mn. A comparison showed that the titanium substitution approach had advantages such as the phase transition being sharper and the magnetization remaining higher than in the case of the earlier known way of TC reduction by decreasing the Sr content from the optimal value of x = 0.3. The new features seem to make La1..xSrxMn₁..yTiyO₃ nanoparticles promising for hyperthermia application.

High-performance liquid chromatography method development for the quality control of Ginkgonis Semen

Le, V.N.H.,Lee, W.,Kim, Y.H.,Chae, G.H.,Chin, Y.W.,Kim, K.T.,Kang, J.S. Elsevier ; King Saud University 2017 Arabian Journal of Chemistry Vol.10 No.6

<P>Ginkgonis Semen (GS) is the seed of Ginkgo biloba Linne and a valuable material for herbal medicines and functional foods in China, Japan and Korea. The main bio-compounds of GS are GA, GB and GC like the leaves. There are many studies for the analysis of ginkgolides in the leaves or leaves extract of G. biloba because the leaves extract is a valuable material in pharmaceutical industries. However, there is no efficient analytical method for the quality control of GS based on the quantitation of ginkgolides because of matrix effect induced by different chemical composition. So, there are no content criteria of GS in Pharmacopoeia of Korea, Japan and China until now. This study aimed to develop HPLC method using ginkgolides based on the quantitation of GA, GB and GC for the quality control of GS with the optimization of sample preparation to enhance the analytical sensitivity and reproducibility. At first, defatting process using petroleum ether and liquid-liquid extraction were applied for sample preparation to remove matrix effect. The HPLC-ELSD method was developed with the mobile phase of a 0.5% aqueous acetic acid and methanol-acetonitrile solution (1: 1 ratio) under gradient conditions. GA, GB and GC contents in GS were different between Korea and China. The mean quantity of Korean samples was 4.85 +/- 2.33 lg/g GA, 48.38 +/- 5.10 lg/g GB, and 37.83 +/- 7.64 lg/g GC. Those contents of Chinese samples were higher than Korean samples as 9.39 +/- 2.51 lg/g GA, 123.59 +/- 26.24 lg/g GB and 53.39 +/- 4.97 lg/g GC. It indicated that the discrimination of GS between Korea and China could be achieved by marker compound contents. Furthermore, the geographical discrimination of GS between Korea and China was confirmed by PCA using the quantitative data of marker compounds. By statistical analysis, the calculated content criteria of GS by regression method were 2.35 lg/g of GA, 29.20 lg/g of GB, and 27.75 lg/g of GC, based on dry weight. Thus, our HPLC method shows potential toward the development of a universal quality control methodology to quantify GS quality and origin. (C) 2016 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University.</P>

COLLOQUIA / CO1-5 : COMPLETE GENE ORDER AND NUCLEOTIDE SEQUENCE OF THE MITOCHONDRIAL GENOMES OF HUMAN SCHISTOSOMES

(T . H . Le),(D . Blair),(P . Humair),(T . Littlewood),(N . Campbell),(D . P . McManus) 한국생화학분자생물학회 (구 한국생화학회) 1999 6th IUBMB SEOUL CONFERENCE Vol.- No.-

Regulatory effect of hydroquinone-tetraethylene glycol conjugates on zebrafish pigmentation

Le, H.T.,Hong, B.N.,Lee, Y.R.,Cheon, J.H.,Kang, T.H.,Kim, T.W. Pergamon Press 2016 Bioorganic & medicinal chemistry letters Vol.26 No.2

We synthesized two hydroquinone-tetraethylene glycol conjugates (HQ-TGs) and investigated their logP, photophysical stability, and redox chemical stability. HQ-TGs are a little more hydrophilic than hydroquinone (HQ) and show an enhanced photophysical and redox chemical stability compared with HQ. In addition we studied the effect of HQ-TGs on cell viability and on zebrafish pigmentation. MTT assay in HF-16 cells showed HQ-TGs are less cytotoxic than HQ. The phenotype-based image analysis of zebrafish larvae suggests that HQ-TGs suppress the pigmentation of zebrafish in a dose-dependent manner. The comparative experiments on stability, cytotoxicity, and zebrafish pigmentation between HQ and HQ-TGs suggest that mono tetraethylene glycol-functionalization of HQ is an alternative solution to overcome the adverse effect of HQ.

Molecular characterization of serotype A foot-and-mouth disease viruses circulating in Vietnam in 2009

Le, V.P.,Nguyen, T.,Lee, K.N.,Ko, Y.J.,Lee, H.S.,Nguyen, V.C.,Mai, T.D.,Do, T.H.,Kim, S.M.,Cho, I.S.,Park, J.H. Elsevier Scientific Pub. Co 2010 Veterinary microbiology Vol.144 No.1

Foot-and-mouth disease (FMD) is a major cause of endemic outbreaks in Vietnam in recent years. In this work, six serotype A foot-and-mouth disease viruses (FMDV), collected from endemic outbreaks during January and February of 2009 in four different provinces in Vietnam, were genetically characterized for their complete genome sequences. Genetic analysis based on the complete viral genome sequence indicated that they were closely related to each other and shared 99.0-99.8% amino acid (aa) identity. Genetic and deduced aa analysis of the capsid coding gene VP1 showed that the six Vietnamese strains were all classified into the genotype IX from a total of 10 major genotypes worldwide, sharing 98.1-100% aa identity each other. They were most closely related to the type A strains recently isolated in Laos (A/LAO/36/2003, A/LAO/½006, A/LAO/6/2006, A/LAO/7/2006, and A/LAO/8/2006), Thailand (A/TAI/2/1997 and A/TAI/118/1987), and Malaysia (A/MAY/2/2002), sharing 88.3-95.5% nucleotide (nt) identities. In contrast, Vietnamese type A strains showed low nt identities with the two old type A FMDVs, isolated in 1960 in Thailand (a15thailand iso43) and in 1975 in the Philippines (aphilippines iso50), ranging from 77.3 to 80.9% nt identity. A multiple alignment based on the deduced amino acid sequences of the capsid VP1 coding gene of type A FMDV revealed three amino acid substitutions between Vietnamese strains and the strains of other Southeast Asian countries (Laos, Thailand, Malaysia, and the Philippines). Alanine was replaced by valine at residue 24, asparagine by arginine at residue 85, and serine by threonine at residue 196. Furthermore, type A FMDV strains recently isolated in Vietnam, Laos, Thailand, and Malaysia all have one amino acid deletion at residue 140 of the capsid VP1 protein compared with the two old type A FMDV strains from Thailand and the Philippines as well as most other type A representatives worldwide. This article is the first to report on the comprehensive genetic characterization of type A FMDV circulating in Vietnam.

Differential expression of ginsenoside biosynthesis-related genes at an early developmental stage of Panax vietnamensis

Ly H. Luu,Pham Hang L. B.,Huynh Hue T. T.,Nguyen Linh N.,Vu Trinh T.,Le Hien T. T. 한국식물생명공학회 2022 Plant biotechnology reports Vol.16 No.2

Panax vietnamensis Ha et Grushv., an important medicinal plant in Vietnam, consists of several valuable ginsenosides. Compared to other Panax species, molecular and in silico studies concerning its transcriptomes and ginsenoside biosyn- thesis-related genes are still lacking. In this study, the transcriptomes of 1-year-old leaves and roots of P. vietnamensis were sequenced and analyzed using the Illumina system. The expression of the selected ginsenoside biosynthesis-related genes was confirmed using real-time PCR. In total, 42,724, 41,564, and 43,021 unigenes were assembled for leaves, roots, and leaf and root tissues, respectively. More than 60% of the unigenes from both tissues were functionally annotated using at least one database from the Kyoto encyclopedia of genes and genomes, Pfam, gene ontology, the National Center for Biotechnol- ogy Information (NCBI) non-redundant protein sequence database, and the evolutionary genealogy of genes. Furthermore, the expression of the predominant transcripts in each cDNA library was analyzed and identified. In addition, 457 unigenes encoding the enzymes involved in ginsenoside biosynthesis were identified. Most genes encoding enzymes related to ginse- noside biosynthesis via both MVA and non-MVA pathways are indicated. Quantitative PCR analysis showed that β-amyrin synthase (β-AS), cytochrome P450 (CYP716A53v2, CYP716A52v2), and UDP-glycosyl transferase (UGT74AE2) were highly expressed, more so in the roots than in the leaves. Our results may answer the question of how genes are expressed and whether ginsenosides are produced and accumulated in the first growing year of P. vietnamensis leaves and roots. This first comprehensive transcriptome data of 1-year-old leaves and roots of P. vietnamensis is useful for further investigation of gin- seng development, biosynthesis, major secondary metabolite pathways, and related gene expression in different tissues and developmental stages. Data also provide useful information for improving ginseng biosynthesis using biotechnology tools.