• Analytical Science and Technology
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• v.26 no.6
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• pp.353-356
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• 2013

A method on the determination of caffeine in beverage with acridiene orange-${\beta}$-cyclodextrin (CD) inclusion complex was developed. The conditions such as pH of the sample solution and concentration of acridine orange and ${\beta}$-CD were optimized to 12.0(${\pm}0.5$), $1.9{\times}10^{-6}M$ and $1.25{\times}10^{-3}M$, respectively. Under these optimum conditions, the calibration curve of caffeine was obtained over concentration range of $5{\times}10^{-5}{\sim}1.1{\times}10^{-3}M$. The detection limit was $1.0{\times}10^{-5}M$. The relative errors(%) in beverage samples were less than 5.0%.

• Journal of Industrial Technology
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• v.2
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• pp.3-11
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• 1982

Reliability analysis methods have been employed in this study to determine the safety index ${\beta}$ for flexure associated with reinforced concrete designs that are in accordance with current USD code of Korea. In reliability analysis, the mean first-order second-moment methods are employed. The following specific conclusions can be drawn from this study; 1) Levels of safety for reinforced concrete design, measured by ${\beta}$, vary from 2.8 to 3.8 in flexure depending on the limit state, the ratio of live load to dead load and the uncertainties. 2) Target reliability ${\beta}$ associated with reinforced concrete beams in flexure is assumed to be 3.5~4.0 in Korea. 3) Load factors and resistance factors in flexure associated with the current provisions contained in USD code generally seem to be too high. The writer concluded the factors as following; ${\phi}=0.8,\;{\gamma}_D=1.1\;{\gamma}_L=1.75$.

• Archives of Pharmacal Research
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• v.21 no.2
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• pp.217-222
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• 1998

A stereospecific HPLC method has been developed for the resolution of the enantiomers of salbutamol in human urine. After solid-phase extraction and derivatization with 2,3,4,6-tetra-O-acetyl-$\beta$-D-glucopyranosyl isothiocyanate, the diastereomeric derivatives were resolved (Rs=1.83) on $5{\mu}m$ octadecylsilan column using 35% acetonitrile in 0.05M ammonium acetate buffer (pH=6) as a mobile phase with electrochemical detection. The diastereomeric derivatives were formed within 30 min. The detection limit of each enantiomer was 20 ng/ml (S/N=3).

• Journal of the Korean Mathematical Society
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• v.32 no.2
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• pp.289-300
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• 1995

Every group G has a unique maximal normal locally nilpotent subgroup $\Phi(G)$, called the Hirsh-Plotkin radical of G [9]. If G is a group, we define the upper Hirsh-Plotkin series of G to be the ascending series $1 = R_0 \leq R_1 \leq \ldots$ in which $R_{\alpha+1}/R_\alpha = \{Phi(G/R_\alpha)$ for each ordinal $\alpha and R_\beta = \cup_{\alpha<\beta}R_\alpha$ for each limit ordinal $\beta$. If $R_r = G$ for some natural number r, then G is said to have locally nilpotent length r. $(LN)^r$ denotes the calss of groups of locally nilpotent length at most r.

• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.698-706
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• 2004

$\beta$-Lactam antibiotics such as penicillin G, amoxicillin, and ampicillin were determined by a potentiometric biosensor system which exploited penicillinase immobilized on Immobilon cellulose nitrate membrane and a flat-bottomed pH electrode-as the biological component and transducer. The optimum reaction buffer for maximum sensitivity was found as 2 mM of sodium phosphate buffer (pH 7.2). The detection limit of the biosensor could be extended to 1 $\mu{M}$ of the analytes by increasing the enzyme loading for immobilization to 100 units/$m\ell$. The model samples spiked with each of the standard penicillins were measured for their biosensor responses and HPLC peak area, resulting in the relative responses of 82.1-103.5% and 79.5-106.1% for the biosensor method along with HPLC analysis, respectively. This result showed a good precision of the current biosensor method for screening the penicillin compounds.

• Applied Biological Chemistry
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• v.34 no.1
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• pp.26-31
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• 1991

The physicochemical properties of starches from dry(Suwon 147) and moist type(Hwangmi) sweet potato were investigated and molecular structural properties of their amylopectins were also studied by gel chromatography. Suwon 147 starch bad lower swelling power and higher gelatinization temperature than Hwangmi starch. $\beta-Amylolysis\;limit(%)$ of Suwon 147 and Hwangmi amylopectin were 57.6% and 57.0%, respectively. Average unit chain length of amylopectins were 24.8 glucose units for Suwon 147 and 21.9 for Hwangmi. The elution profiles by Sephadex G-50 after debranched amylopectins of the two starches were similar but DPs of each peak were different.

• Molecules and Cells
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• v.23 no.3
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• pp.340-348
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• 2007

Although considerable effort has been devoted in the mass spectrometric analysis of phosphorylated peptides, successful identification of multi-phosphorylated peptides in enzymatically digested protein samples still remains challenging. The ionization behavior of multi-phosphorylated peptides appears to be somewhat different from that of mono- or di-phosphorylated peptides. In this study, we demonstrate increased sensitivity of detection of multi-phosphorylated peptides of beta casein without using phosphopeptide enrichment techniques. Proteinase K digestion alone increased the detection limit of beta casein multi-phosphorylated peptides in the LC-MS analysis almost 500 fold, compared to conventional trypsin digestion (~50 pmol). In order to understand this effect, various factors affecting the ionization of phosphopeptides were investigated. Unlike ionizations of phosphopeptides with minor modifications, those of multi-phosphorylated peptides appeared to be subject to effects such as selectively suppressed ionization by more ionizable peptides and decreased ionization efficiency by multi-phosphorylation. The enhanced detection limit of multi-phosphorylated peptides resulting from proteinase K digestion was validated using a complex protein sample, namely a lysate of HEK 293 cells. Compared to trypsin digestion, the numbers of phosphopeptides identified and modification sites per peptide were noticeably increased by proteinase K digestion. Non-specific proteases such as proteinase K and elastase have been used in the past to increase detection of phosphorylation sites but the effectiveness of proteinase K digestion for multi-phosphorylated peptides has not been reported.

• Archives of Pharmacal Research
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• v.25 no.6
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• pp.903-909
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• 2002

Research in the cytokine field has grown exponentially in recent years, and the validity of such studies relies heavily on the appropriate measurement of levels of cytokines in various biological samples. Transforming growth factor (TGF)-$\beta$, a hormonally active polypeptide found in normal and transformed tissue, is a potent regulator of cell growth and differentiation. The most widely used bioassay for TGF-$\beta$ is the inhibition of the proliferation of mink lung epithelial cells. Though detection of [$^3$H]thymidine incorporation is more sensitive than the MTT assay, it presents some disadvantages due to the safety and disposal problems associated with radioisotopes. In this study, we attempted to ascertain the experimental conditions which could be used for measuring the in vitro biological activity of TGF-$\beta$ in a safer and more sensitive way compared with the currently available methods. We compared the commonly used method, the MTT assay, to the XTT assay using different parameters including cell number, incubation time and the wave length used for detecting the product. We examined the anti-proliferative activities of TGF-$\beta$ in three different cell lines: Mv-1-Lu mink lung epithelial cells, MCF10A human breast epithelial cells and H-ras-transformed MCF10A cells. Herein, we present an experimental protocol which provides the most sensitive method of quantifying the biological activity of TGF-$\beta$, with a detection limit of as low as 10 pg/ml: Mv-1-Lu or H-ras MCF10A cells ($1{\times}10^5/well$) were incubated with TGF-$\beta$ at $37^{\circ}C$ in a humidified $CO_2$ incubator for 24 hr followed by XTT treatment and determination of absorbance at 450 or 490 nm. Our results may contribute to the establishment of an in vitro bioassay system, which could be used for the satisfactory quantitation of TGF-$\beta$.

• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.92-96
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• 1997

A Korean commercial sweet rice drink "Sikhye" showed sucrose, fructose, glucose, maltose, limit dextrin and various size of maltooligosaccharides in HPLC and TLC analysis. Commercial Sikhye was found to contain 0.09% of limit dextrin and 0.2% of rice residue. Limit dextrin in commercial Sikhye showed both signal of $\alpha$-1,4- and $\alpha$-1,6-glucosidic linkage with its estimation ratio of 15:1 by 1H-NMR analysis. This limit dextrin was hydrolyzed to produce various size of maltooligosaccarides with more longer chain than that of traditional Sikhye by pullulanase. Limit dextrin was digested wit enzymes(30units/ml) of $\alpha$-amylase, $\alpha$-glucosidase and glucoamylase from Aspergillus awamori, sweet potato $\beta$-amylase and human salivary $\alpha$-amylase at 37$^{\circ}C$ for 1 hour, respectively. Hydrolysis rates of these amylases on it were higher than in case of traditional sikhye. $\alpha$-Glucosidase plus human salivary $\alpha$-amylase hydrolyzed it to 61.3%. Hydrolysis rates of these amylases on rice residue were lower than that of traditional Sikye. These results suggest that limit dextrin in commercial Sikhye is less effective than isomaltooligosaccharides in traditional Sikhye as a growth factor for Bifidobacterium while rice residue in commercial Sikhye is more effective than that in traditional Sikhye as dietary fiber.ary fiber.

• Journal of Microbiology and Biotechnology
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• v.29 no.3
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• pp.357-366
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• 2019

We first confirmed the involvement of MalQ (4-${\alpha}$-glucanotransferase) in Escherichia coli glycogen breakdown by both in vitro and in vivo assays. In vivo tests of the knock-out mutant, ${\Delta}malQ$, showed that glycogen slowly decreased after the stationary phase compared to the wild-type strain, indicating the involvement of MalQ in glycogen degradation. In vitro assays incubated glycogen-mimic substrate, branched cyclodextrin (maltotetraosyl-${\beta}$-CD: G4-${\beta}$-CD) and glycogen phosphorylase (GlgP)-limit dextrin with a set of variable combinations of E. coli enzymes, including GlgX (debranching enzyme), MalP (maltodextrin phosphorylase), GlgP and MalQ. In the absence of GlgP, the reaction of MalP, GlgX and MalQ on substrates produced glucose-1-P (glc-1-P) 3-fold faster than without MalQ. The results revealed that MalQ led to disproportionate G4 released from GlgP-limit dextrin to another acceptor, G4, which is phosphorylated by MalP. In contrast, in the absence of MalP, the reaction of GlgX, GlgP and MalQ resulted in a 1.6-fold increased production of glc-1-P than without MalQ. The result indicated that the G4-branch chains of GlgP-limit dextrin are released by GlgX hydrolysis, and then MalQ transfers the resultant G4 either to another branch chain or another G4 that can immediately be phosphorylated into glc-1-P by GlgP. Thus, we propose a model of two possible MalQ-involved pathways in glycogen degradation. The operon structure of MalP-defecting enterobacteria strongly supports the involvement of MalQ and GlgP as alternative pathways in glycogen degradation.