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Kim, Yoon,Kim, Unyong,Kim, In Sook,Lee, Sung-Hack,Lee, Jaeick,Kim, Dong-Hyun,Yoo, Hye Hyun Informa UK Ltd. 2014 Xenobiotica Vol.44 No.7
<P>1. The absorption, distribution, metabolism and excretion of a novel dipeptidyl peptidase IV inhibitor, gemigliptin, were examined following single oral administration of <SUP>14</SUP>C-labeled gemigliptin to rats.</P><P>2. The <SUP>14</SUP>C-labeled gemigliptin was rapidly absorbed after oral administration, and its bioavailability was 95.2% (by total radioactivity). Distribution to specific tissues other than the digestive organs was not observed. Within 7 days after oral administration, 43.6% of the administered dose was excreted via urine and 41.2% was excreted via feces. Biliary excretion of the radioactivity was about 17.7% for the first 24 h. After oral administration of gemigliptin to rats, the <I>in vivo</I> metabolism of gemigliptin was investigated with bile, urine, feces, plasma and liver samples.</P><P>3. The major metabolic pathway was hydroxylation, and the major circulating metabolites were a dehydrated metabolite (LC15-0516) and hydroxylated metabolites (LC15-0635 and LC15-0636).</P>
Kim, Jin-Seong,Kim, Jae-Han,Lee, Wonho,Yu, Hojeong,Kim, Hyeong Jun,Song, Inho,Shin, Minkwan,Oh, Joon Hak,Jeong, Unyong,Kim, Taek-Soo,Kim, Bumjoon J. American Chemical Society 2015 Macromolecules Vol.48 No.13
<P>While the regioregularity (RR) of conjugated polymers is known to have a strong influence on their inherent properties, systematic study of the RR effect has been limited due to the lack of a synthetic methodology. Herein, we successfully produced a series of poly(3-hexylthiophene)s (P3HTs) having a wide range of RR from 64 to 98%. Incorporation of controlled amounts of head-to-head (H-H) coupled dimer in modified Grignard metathesis polymerization allows a facile tuning of the RR of the P3HTs with comparable molecular weight and low polydispersity. Then, we investigated the effect of RR on structural, electrical, and mechanical properties of P3HTs in which a higher content of H-H regio-defects, namely lower RR, systematically lowered the degree of crystallinity. Although high RR P3HT (98%) had higher charge carrier mobility (1.81 x 10(-1) cm(2) V-1 s(-1)), its strong crystallinity induced high brittleness and stiffness, resulting in device failure under a very small strain, as shown in tensile and bending tests. The tensile modulus was reduced significantly from 287 MPa (RR 98%) to 13 MPa (RR 64%), and also the RR 64% P3HT film had much better mechanical resilience with an order of magnitude higher elongation at break than that of the RR 98% polymer. Our findings suggest that the mechanical and electrical properties of conjugated polymers can be systematically tuned by controlling the RR to meet the purposes of various organic electronic applications, i.e., flexible portable devices vs high-performance panels.</P>
Hygroscopic Auxetic On-Skin Sensors for Easy-to-Handle Repeated Daily Use
Kim, Hyun Woo,Kim, Tae Yeong,Park, Hyung Keun,You, Insang,Kwak, Junghyeok,Kim, Jong Chan,Hwang, Heeseon,Kim, Hyoung Seop,Jeong, Unyong American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.46
<P>Despite the advance of on-skin sensors over the last decade, a sensor that solves simultaneously the critical issues for using in everyday life, such as stable performance in various environments, use over a long period of time, and repeated use by easy handling, has not yet been achieved. Here, we introduce an auxetic hygroscopic sensor that simultaneously meets all of the conditions. The auxetic structure with a negative Poisson’s ratio matches with deformation of the skin in ankles; hence, a conformal contact between the sensor and the skin could be maintained during repeated movements. Sweat was absorbed in the auxetic electrode made of a hydrogel pattern coated with Ag nanowires and evaporated quickly; such hygroscopic characteristic led to excellent breathability. An electrocardiogram sensor and a haptic device were fabricated according to the proposed design for a sensor electrode. The sensors provide stable detecting performance in various environments, such as exercising, submersion in water, exposure to concentrated salt water, and continuous wearing for long time (7 days). Also, the sensors could be manually attached repeatedly without degrading the performance. This study provides new structural insights for on-skin sensors and presents future research directions.</P> [FIG OMISSION]</BR>
Jin, Ming Ji,Kim, Unyong,Kim, In Sook,Kim, Yuri,Kim, Dong-Hyun,Han, Sang Beom,Kim, Dong-Hyun,Kwon, Oh-Seung,Yoo, Hye Hyun Taylor Francis 2010 Journal of toxicology and environmental health. Pa Vol.73 No.21
<P>Hesperidin is a biologically active flavanone glycoside occurring abundantly in citrus fruits. In the present study, effects of intestinal microflora on pharmacokinetics of hesperidin were investigated using a pseudo-germ-free rat model treated with antibiotics. After administration of hesperidin to rats, hesperetin, hesperetin glucuronides, and metabolites postulated to be eriodictyol, hemoeriodictyol, and their glucuronides were detected in urine while hesperetin glucuronide was predominantly found in plasma. The plasma concentration-time profile of hesperetin was compared between non-antibiotic-exposed and pseudo-germ-free rats administered this compound. The maximal concentration (C(max)) values of hesperetin in non-antibiotic-exposed and pseudo-germ-free rats were 0.58 and 0.20 관g/ml, respectively, and area under the curve (AUC) values were 6.3 and 2.8 관g-h/ml, respectively. Thus, systemic exposure as evidenced by AUC and C(max) was significantly higher in normal compared to pseudo-germ-free rats. Fecal 관-glucosidase activities of non-antibiotic-exposed and pseudo-germ-free rats were 0.21 and 0.11 nmol/min/mg, while fecal 관-rhamnosidase activities were 0.37 and 0.12 nmol/min/mg, respectively. The rate of hesperidin transformation to hesperetin was 6.9 and 2.9 nmol/min/g in fecal samples in non-antibiotic-exposed and pseudo-germ-free rats, respectively. Taken together, these results showed that pharmacokinetic differences between non-antibiotic-exposed and pseudo-germ-free rats may be attributed to differing hesperidin uptake, as well as alterations in metabolic activities of intestinal flora.</P>
Kim, Min Kyung,Yang, Dong-Hyug,Jung, Mihye,Jung, Eun Ha,Eom, Han Young,Suh, Joon Hyuk,Min, Jung Won,Kim, Unyong,Min, Hyeyoung,Kim, Jinwoong,Han, Sang Beom Elsevier 2011 Journal of chromatography A Vol.1218 No.37
<P><B>Abstract</B></P><P>Methods using high performance liquid chromatography with diode array detection (HPLC-DAD) and tandem mass spectrometry (HPLC–MS/MS) were developed and validated for the simultaneous determination of 5 chromones and 6 coumarins: prim-<I>O</I>-glucosylcimifugin (1), cimifugin (2), nodakenin (3), 4′-<I>O</I>-β-<SMALL>D</SMALL>-glucosyl-5-<I>O</I>-methylvisamminol (4), sec-<I>O</I>-glucosylhamaudol (5), psoralen (6), bergapten (7), imperatorin (8), phellopterin (9), 3′-<I>O</I>-angeloylhamaudol (10) and anomalin (11), in Radix Saposhnikoviae. The separation conditions for HPLC-DAD were optimized using an Ascentis Express C18 (4.6mm×100mm, 2.7μm particle size) fused-core column. The mobile phase was composed of 10% aqueous acetonitrile (A) and 90% acetonitrile (B) and the elution was performed under a gradient mode at a flow rate of 1.0mL/min. The detection wavelength was set at 300nm. The HPLC-DAD method yielded a base line separation of the 11 components in 50% methanol extract of Radix Saposhnikoviae with no interfering peaks detected. The HPLC-DAD method was validated in terms of linearity, accuracy and precision (intra- and inter-day), limit of quantification (LOQ), recovery, and robustness. Specific determination of the 11 components was also accomplished by a triple quadrupole tandem mass spectrometer equipped with an electrospray ionization (ESI) source. This HPLC–MS/MS method was also validated by determining the linearity, limit of quantification, accuracy, and precision. Quantification of the 11 components in 51 commercial Radix Saposhnikoviae samples was successfully performed using the developed HPLC-DAD method. The identity, batch-to-batch consistency, and authenticity of Radix Saposhnikoviae were successfully monitored by the proposed HPLC-DAD and HPLC–MS/MS methods.</P>
Highly Sensitive and Selective Analytical Platform for Non-human Sialic acid
Unyong Kim,Myung Jin Oh,Nari Seo,Jaekyung Ko,Hyun Joo An 한국당과학회 2018 한국당과학회 학술대회 Vol.2018 No.01
Glycosylation, which is susceptible to the biochemical environments, is one of the most important post translational modifications in eukaryotic proteins. Moreover, glycans are involved in many important biochemical events. Especially, sialic acids which are expressed as outer terminal units on all vetebrate are play fundamental roles in cell-to-cell and cell-to-microenvionment interactions. N-acetylneuraminic acid (NeuAc) and N-acetylglycolylneuraminic acid (NeuGc) are predominant sialic acids on most mammalian cells. Unlike other mammalian except chicken, human cannot biosynthesize the NeuGc due to irreversible mutation on gene CMAH encoding CMP-N-acetylneuraminic acid hydroxylase that convert CMP-NeuAc to CMP-NeuGc. When the NeuGc is metabolically incorporated into human tissue from dietary sources (especially red meat), the anti-NeuGc antibodies which leads immune response will be produced and circulated through blood. The evidence showed that the such anti-NeuGc antibodies may cause systemic inflammation and finally can promote tumor progression. Therefore, quantitation of the non-human sialic acid NeuGc in food and therapeutic glycoproteins is of high importance. Here, we introduce analytical methods for rapid and highly sensitive identification and quantitation of NeuGc in food contents containing non-human glycan epitope using LC-MS/MS.
( Unyong Kim ),( Sang Beom Han ),( Oh-seung Kwon ),( Hye Hyun Yoo ) 한국질량분석학회 2011 Mass spectrometry letters Vol.2 No.1
The purpose of this study is to investigate the in vitro metabolism of hesperetin, a bioflavonoid. Hesperetin was incubated with rat liver microsomes in the presence of NADPH and UDP-glucuronic acid for 30 min. The reaction mixture was analyzed by liquid chromatography-ion trap mass spectrometer and the chemical structures of hesperetin metabolites were characterzed based on their MS/MS spectra. As a result, a total of five metabolites were detected in rat liver microsomes. The metabolites were identified as a de-methylated metabolite (eriodictyol), two hesperetin glucuronides, and two eriodictyol glucuronides.