• Journal of Environmental Health Sciences
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• v.22 no.1
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• pp.36-44
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• 1996

A comparison was made of two detection methods(UV absorbence detection and fluorescence detection with pre-column derivatization, with trifluoroacetic acid) coupled with HPLC for the simultaneous determination of aflatoxin $B_1, B_2, G_1$ and $G_2$. A good separation of the four aflatoxins was achieved on a reversed-phase $C_{18}$ column (30 cm x 3.9 mm) with methanol-acetonitrile-water(20+20+60) for absorbence detection or acetonitrile-water(25+75) for fluorescence detection at the flow rate of 1.0 ml/min. The calibration graphs were linear over the ranges 100 ppb-1 ppm for $B_1/G_1$ and 30~300 ppb for $B_2/G_1$ with absorbence detection, and 1~500 ppb for $B_1/G_1$ and 0.3~150 ppb for $B_2/G_2$ with fluorescence detection. The correlation coefficients were greater than 0.94 and 0.99 for absorbance detection and for fluorescence detection, respectively. The detection limit was 100 ng for $B_1/G_1$ and 30 ng for $B_2/G_2$ with absorbence detection, and 1 ng for $B_1/G_1$ and 0.3 ng for $B_2/G_2$ with fluorescence detection. Recovery rates of aflatoxin $B_1, B_2, G_1$ and $G_2$ added to yeast-extract sucrose broth medium were 66.6%, 59.4%, 67.5% and 59.2%, respectively, for absorbence detection and 82.9%, 71.5%, 80.0% and 69.3%, respectively, for fluorescence detection. The four aflatoxins in culture medium were quantitatively detected by the two methods. The aflatoxins in the rice sample were not detected the absorbence detection method, but were below 10 ppb using the fluorescence detection method. Analysis of aflatoxins by both the absorbence and fluorescence methods coupled with HPLC showed acceptable linearity and good recovery. The absorbence detection was less timeconsuming and safer for treatment. The fluorescence detection was more elective and sensitive though elevated $B_1$ and $G_1$ contents were determined from the TFA-induced conversion of $B_1$ to $B_{2a}$ and $G_1$ to $G_{2a}$.

• Journal of applied mathematics & informatics
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• v.25 no.1_2
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• pp.383-388
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• 2007

A (g, f)-factor F of a graph G is Called a Hamiltonian (g, f)-factor if F contains a Hamiltonian cycle. The binding number of G is defined by $bind(G)\;=\;{min}\;\{\;{\frac{{\mid}N_GX{\mid}}{{\mid}X{\mid}}}\;{\mid}\;{\emptyset}\;{\neq}\;X\;{\subset}\;V(G)},\;{N_G(X)\;{\neq}\;V(G)}\;\}$. Let G be a connected graph, and let a and b be integers such that $4\;{\leq}\;a\;<\;b$. Let g, f be positive integer-valued functions defined on V(G) such that $a\;{\leq}\;g(x)\;<\;f(x)\;{\leq}\;b$ for every $x\;{\in}\;V(G)$. In this paper, it is proved that if $bind(G)\;{\geq}\;{\frac{(a+b-5)(n-1)}{(a-2)n-3(a+b-5)},}\;{\nu}(G)\;{\geq}\;{\frac{(a+b-5)^2}{a-2}}$ and for any nonempty independent subset X of V(G), ${\mid}\;N_{G}(X)\;{\mid}\;{\geq}\;{\frac{(b-3)n+(2a+2b-9){\mid}X{\mid}}{a+b-5}}$, then G has a Hamiltonian (g, f)-factor.

• Journal of Food Hygiene and Safety
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• v.13 no.1
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• pp.41-46
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• 1998

A postcolumn derivatization method was tried for the simultaneous determination of four major aflatoxins ($B_1,\;B_2,\;G_1,\;and\;G_2$) by high-performance liquid chromatography with fluorescence detection. As compared with a previous precolumn derivatization method, it was found that the postcolumn derivatization combined with an electrochemical cell (Kobra cell) was less time-consuming, safer, improved the sensitivity and selectivity, and provided good recoveries for aflatoxin $B_1$ (88.9%) and $G_1$ (100.5%). This method showed linearity from 10~100 ppb for aflatoxin $B_1\;and\;G_1$, and from 3~30 ppb for aflatoxin $B_2\;and\;G_2$. However, aflatoxin Bz and Gz were not detected satisfactorily although they showed good resolution.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.569-574
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• 1999

One hundred and ninety seven corn samples, which collected from each local province in Korea between 1995 and 1996, were analyzed for fumonisin $B_1\;(FB_1)$ and $B_2\;(FB_2)$ contamination using fluometric HPLC. $FB_1$ and $FB_2$ were detected in 143 (72.6%) and 128 (62.4%) samples from 197 samples at the concentrations ranging from 0 to $224.2\;{\mu}g/g$ for $FB_1$ and from 0 to $60.0\;{\mu}g/g$ for $FB_2$, respectively. The total fumonisin levels analyzed from 143 samples were 15.4, 37.5 and 14% for concentrations below $10\;{\mu}g/g$, above $10\;{\mu}g/g$ and above $30\;{\mu}g/g$, respectively. The total fumonisin levels containing above $10\;{\mu}g/g$ were detected the highest concentration with 53.2% in samples collected from Kangwon, and followed by Kyeongki (45.0%), Cheonbuk (40.0%), Chungbuk (26.9%) and Kyeongbuk (11.1%). The total fumonisin level containing above $10\;{\mu}g/g$ in samples collected in 1996 was higher than that in 1995. Both fumonisin $B_1$ and $B_2$ from samples collected in 1995 were detected higher than that in 1996 and $FB_1$ was detected the highest level in samples collected from Kyeongki province and followed by Kangwon, Cheonbuk, Chungbuk and Kyeogbuk (11.1%). Also, similar results were observed in $FB_2$.

• Bulletin of the Korean Mathematical Society
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• v.58 no.1
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• pp.31-46
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• 2021

Let a and b be positive integers, and let V (G), ��(G), and ��2(G) be the vertex set of a graph G, the minimum degree of G, and the minimum degree sum of two non-adjacent vertices in V (G), respectively. An even [a, b]-factor of a graph G is a spanning subgraph H such that for every vertex v ∈ V (G), dH(v) is even and a ≤ dH(v) ≤ b, where dH(v) is the degree of v in H. Matsuda conjectured that if G is an n-vertex 2-edge-connected graph such that $n{\geq}2a+b+{\frac{a^2-3a}{b}}-2$, ��(G) ≥ a, and ${\sigma}_2(G){\geq}{\frac{2an}{a+b}}$, then G has an even [a, b]-factor. In this paper, we provide counterexamples, which are highly connected. Furthermore, we give sharp sufficient conditions for a graph to have an even [a, b]-factor. For even an, we conjecture a lower bound for the largest eigenvalue in an n-vertex graph to have an [a, b]-factor.

• Journal of Microbiology and Biotechnology
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• v.11 no.3
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• pp.482-490
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• 2001

The gene for glycoprotein B (gB2) of HSV-2-strain G was subcloned, sequenced, recombinated into the lacZ-HcNPV, expressed in insect cells, and compared with the homologous gene of other HSV-2 strains. The ORF of the gB2 gene was 2,715 bp. The overall nucleotide sequence homology of te gB2 gene compared ith that of the two previously reported HSV-2 strains appeared to be over 98%. A recombinant virus named Baculo-gB2 protein in insect cells. The recombination was confirmed by a PCR and the expression was demonstrated by radio immunoprecipitation. Insect cells infected with the Baculo-gB2 virus synthesized and processed gB2 with approximately 120 kDa in the cells, and then secreted it into the culture media, where it reacted with a nomoclonal antibody to gB2. The gB2 polypeptide contained two main hydrophobic regions (a signal sequence from 1 to 23 amino acid residues, and a membrane anchor sequence from aa 745 to 798), eight N-glycosylation sites evenly distributed, and was rich in alanine (11.2%). Antibodies to this recombinant protein that were raised in mice recognized the viral gB2 and neutralized the infectivity of the HSV-2 in vitro. There results show that the gB2 protein was successfully porduced in insect cells and could be used to raise a protective neutralizing antibody. Accordingly, this particular recombinant protein may be useful in the development of a subunit vaccine.

• Journal of the Korean Applied Science and Technology
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• v.36 no.4
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• pp.1119-1127
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• 2019

This study analyzes the content of niacin, B1, and B2, which are among the water-soluble vitamin B group, in cultivars of the commonly consumed agricultural products of apples, peaches, nectarines and strawberries to compare content differences and to use results as base material for the Korean Food Composition Table. While the vitamin B1 content of apples according to different cultivars was found to be within the ranges of 0.063-0.208 mg/100g, and the content of vitamin B2 was found to be within the value ranges of 0.006-0.031 mg/100g, no niacin was found. The vitamin B1 content of peaches and nectarines according to different cultivars was found to be within the value ranges of 0.014-0.276 mg/100g, the content of vitamin B2 was found to be within he value ranges of 0.019-0.042 mg/100g, and niacin content was found to be within the value ranges of 0.298-1.096 mg/100g. The vitamin B1 content of strawberries according to cultivars was found to be within the value ranges of 0.112-0.394 mg/100g, the content of vitamin B2 was found to within the value ranges of 0.001-0.027 mg/100g, and niacin content was found to be within the value ranges of 0.388-0.809 mg/100g. Therefore, when nutrient composition analysis databases for the fruits of apples, peaches, and strawberries are constructed, cultivar factors must be put into consideration. In addition, differences can be found according to fruit harvest times, cultivation methods, and environmental factors, so related additional is needed.

• Management & Information Systems Review
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• v.21
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• pp.99-114
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• 2007

According as Internet based EC(Electronic Commerce) has been activated, More requirements for exchanging digital documents are being proposed in B2B(Business to Business) and B2G(Business to Government) environments. However, the documents can not be processed automatically, because the structures of documents in each site(companies, central/local governments) do not match. Therefore, W3C(World Wide Web Consortium) has proposed XML(eXtensible Markup Language) DTD(Document Type Declaration) technology to support structuring documents. The XML DTD technology can support interoperability between EC sites. And, XML DTD based documents can be processed automatically in every sites. They will improve efficiency of services in B2B and B2G environments. In this paper, we propose interoperable DTD architecture and IDEP(Interoperable DTD Exchange Protocol) protocol which supports searching DTDs and exchanging DTDs. This technology can popularize DTDs and digital documents.

• Journal of Food Hygiene and Safety
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• v.32 no.4
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• pp.267-274
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• 2017

This paper deals with the natural occurrence of total aflatoxins ($B_1$, $B_2$, $G_1$, and $G_2$) in commercial herbs for food and medicine. To monitor aflatoxins in commercial herbs for food and medicine not included in the specifications of Food Code, a total of 62 samples of 6 different herbs (Bombycis Corpus, Glycyrrhizae Radix et Rhizoma, Menthae Herba, Nelumbinis Semen, Polygalae Radix, Zizyphi Semen) were collected from Yangnyeong market in Seoul, Korea. The samples were treated by the immunoaffinity column clean-up method and quantified by high performance liquid chromatography (HPLC) with on-line post column photochemical derivatization (PHRED) and fluorescence detection (FLD). The analytical method for aflatoxins was validated by accuracy, precision and detection limits. The method showed recovery values in the 86.9~114.0% range and the values of percent coefficient of variaton (CV%) in the 0.9~9.8% range. The limits of detection (LOD) and quantitation (LOQ) in herb were ranged from 0.020 to $0.363{\mu}g/kg$ and from 0.059 to $1.101{\mu}g/kg$, respectively. Of 62 samples analyzed, 6 semens (the original form of 2 Nelumbinis Semen and 2 Zizyphi Semen, the powder of 1 Nelumbinis Semen and 1 Zizyphi Semen) were aflatoxin positive. Aflatoxins $B_1$ or $B_2$ were detected in all positive samples, and the presence of aflatoxins $G_1$ and $G_2$ were not detected. The amount of total aflatoxins ($B_1$, $B_2$, $G_1$, and $G_2$) in the powder and original form of Nelumbinis Semen and Zizyphi Semen were observed around $ND{\sim}21.8{\mu}g/kg$, which is not regulated presently in Korea. The 56 samples presented levels below the limits of detection and quantitation.

• Journal of applied mathematics & informatics
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• v.28 no.1_2
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• pp.325-331
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• 2010

Let a and b be nonnegative integers with 2 $\leq$ a < b, and let G be a Hamiltonian graph of order n with n > $\frac{(a+b-5)(a+b-3)}{b-2}$. An [a, b]-factor F of G is called a Hamiltonian [a, b]-factor if F contains a Hamiltonian cycle. In this paper, it is proved that G has a Hamiltonian [a, b]-factor if $\delta(G)\;\geq\;\frac{(a-1)n+a+b-3)}{a+b-3}$ and $\delta(G)$ > $\frac{(a-2)n+2{\alpha}(G)-1)}{a+b-4}$.