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Biomimetic mineralization of vertical N-doped carbon nanotubes
Lee, Won Jun,Lee, Duck Hyun,Han, Tae Hee,Lee, Sun Hwa,Moon, Hyoung-Seok,Lee, Jin Ah,Kim, Sang Ouk Royal Society of Chemistry 2011 Chemical communications Vol.47 No.1
<P>Biomimetic mineralization of vertical N-doped carbon nanotubes is demonstrated as a straightforward route for carbon-based mineral nanocomposites. The N-doped sites along the carbon nanotube backbone play the role of nucleation sites for mineralization.</P> <P>Graphic Abstract</P><P>The N-doped sites along the carbon nanotube backbone play the role of nucleation sites for biomimetic mineralization. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0cc04237d'> </P>
Antioxidant Activities and Determination of Phenolic Acids from Leaves of Perilla frutescens
Lee, Jin-Hwan,Kang, Nam-Suk,Ha, Tae-Joung,Ko, Jong-Min,Han, Won-Young,Suh, Duck-Yong,Park, Ki-Hun,Baek, In-Youl The Korean Society for Applied Biological Chemistr 2006 Journal of Applied Biological Chemistry (J. Appl. Vol.49 No.1
Two catecholic phenolic acids (1 and 2) obtained from 80% methanolic extract of Perilla frutescens var. frutescens leaves through chromatography showed strong DPPH (1: $IC_{50}$ = 15.5 ${\mu}M$, 2: $IC_{50}$ = 11.7 ${\mu}M$) and ABTS (1: $IC_{50}$ = 5.5 ${\mu}M$, 2: $IC_{50}$ = 4.6 ${\mu}M$) radicals scavenging abilities. Antioxidant compounds contents of 1 and 2 as determined by $C_{18}$ reversed phase HPLC coupled with diode-array detector were 2.98 and 2.26 mg/g, respectively.
Lee, Hyo-Kyoung,Yeo, Hee-Kyoung,Park, Duck-Hee,Jeon, Seung-Won Korean Chemical Society 2003 Bulletin of the Korean Chemical Society Vol.24 No.12
Azo-functionalized calix[4]arenes as ionophores for chloride-selective electrode, 5,11,17,23-Tetra-tert-butyl-25,27-bis[(N,N-dimethyl-aniline-azo-phenylthioureido)ethyl]oxy-26,28-dihydroxycalix[4]arene (4a) and 5,11,17,23-Tetra-tert-butyl-25,27-bis[(N,N-dimethyl-aniline-azo-phenylthioureido)ethyl]oxy-26,28-dimethoxycalix[4]arene (4b) were synthesized. The PVC membrane electrode based on azo-functionalized calix[4]arene 4a with o-NPOE exhibits a linear stable response over a wide concentration range ($1.5{\times}10^{-4}-1.0{\times}10^{-1}$) with a slope of -52.0 mV/decade and a detection limit of log[$Cl^-$] = -4.02. This ionophore-based membrane exhibited improved selectivity for chloride anion compared with classical Hofmeister series.
Duck Min Seo,Sang Min Lee,Park Ji Won,Min-Jeong Kim,Ha Hong Il,Sun-Young Park,이관섭 대한초음파의학회 2023 ULTRASONOGRAPHY Vol.42 No.2
Purpose: This retrospective study aimed to determine the number of times the ultrasound-guided attenuation parameter (UGAP) should be measured during the evaluation of hepatic steatosis. Methods: Patients with suspected nonalcoholic fatty liver disease who underwent two UGAP repetition protocols (six-repetition [UGAP_6] and 12-repetition [UGAP_12]) and measurement of the controlled attenuation parameter (CAP) using transient elastography between October 2020 and June 2021 were enrolled. The mean attenuation coefficient (AC), interquartile range (IQR)/median, and coefficient of variance (CV) of the two repetition protocols were compared using the paired t test. Moreover, the diagnostic performances of UGAP_6 and UGAP_12 were compared using the area under the receiver operating characteristic (AUROC) curve, considering the CAP value as a reference standard. Results: The study included 160 patients (100 men; mean age, 50.9 years). There were no significant differences between UGAP_6 and UGAP_12 (0.731±0.116 dB/cm/MHz vs. 0.734±0.113 dB/cm/MHz, P=0.156) and mean CV (7.6±0.3% vs. 8.0±0.3%, P=0.062). However, the mean IQR/median of UGAP_6 was significantly lower than that of UGAP_12 (8.9%±6.0% vs. 9.8%±5.2%, P=0.012). In diagnosing the hepatic steatosis stage, UGAP_6 and UGAP_12 yielded comparable AUROCs (≥S1, 0.908 vs. 0.897, P=0.466; ≥S2, 0.883 vs. 0.897, P=0.126; S3, 0.832 vs. 0.834, P=0.799). Conclusion: UGAP had high diagnostic performance in diagnosing hepatic steatosis, regardless of the number of repetitions (six repetitions vs. 12 repetitions), with maintained reliability. Therefore, six UGAP measurements seem sufficient for evaluating hepatic steatosis using UGAP.
Vacuum Packaging Technology of AC-PDP using Direct-Joint Method
Lee, Duck-Jung,Lee, Yun-Hi,Moon, Gwon-Jin,Kim, Jun-Dong,Choi, Won-Do,Lee, Sang-Geun,Jang, Jin,Ju, Byeong-Kwon The Korean Infomation Display Society 2001 Journal of information display Vol.2 No.4
We suggested new PDP packaging technology using the direct joint method, which does not need an exhausting hole and tube. The advantages of this method are simple process, short process time and time panel package. To packaging, we drew the seal line of glass frit by dispenser followed by forming the lump, which provide pumping-out path during the packaging process. And, we have performed a pretreatment of glass frit to reduce the out-gases. After which, both front and rear glass plates were aligned and loaded into vacuum packaging chamber. The 4-inch monochrome AC-PDP was successfully packaged and fully emitted with brightness of 1000 $cd/m^2$. Also, glass frit properties for pretreatment condition was investigated by AES and SEM analyses.
A novel mutation in the DAX1 gene in a newborn with adrenal hypoplasia congenita in Korea
Lee, Juyeen,Kim, Won Duck,Kim, Hae Sook,Lee, Eun Kyung,Park, Hyung Doo Korean Society of Medical Genetics and Genomics 2017 대한의학유전학회지 Vol.14 No.1
Adrenal hypoplasia congenita (AHC) is a rare cause of adrenal insufficiency during neonatal period. Mutations in the gene coding for DAX1 cause X-linked adrenal hypoplasia. Most affected patients are shown to have salt wasting and hyperpigmentation on the skin during the neonatal period and require intensive medical care. In addition, it is usually associated with hypogonadotropic hypogonadism in adolescence. The DAX1 gene is expressed in the adrenal cortex, pituitary gland, hypothalamus, testis, and ovary. We report on a patient with genetically confirmed AHC whose initial clinical presentations were consistent with congenital adrenal hyperplasia. A point mutation in the DAX1 gene identified in this report resulted in a truncated DAX1 protein. Our patient was diagnosed with AHC.
Highly efficient vertical growth of wall-number-selected, N-doped carbon nanotube arrays.
Lee, Duck Hyun,Lee, Won Jong,Kim, Sang Ouk American Chemical Society 2009 NANO LETTERS Vol.9 No.4
<P>We demonstrate a straightforward approach for rapid growth of wall-number selected, N-doped CNT arrays. Highly uniform nanopatterned iron catalyst arrays were prepared by tilted deposition through block copolymer nanotemplates. PECVD growth of CNTs from the nanopatterned catalysts in an NH(3) environment generated vertical N-doped CNTs with a fine-tunability of their carbon wall numbers. The optimized growth conditions produced 52 microm long N-doped CNTs within 1 min. Owing to N-doping, the wall-number selected CNTs including DWNTs and TWNTs demonstrated enhanced electro-conductivity and chemical functionality. This remarkably fast growth of highly uniform N-doped CNTs, whose material properties and chemical functionalizability are reinforced by N-doping, offers a new area of large-scale nanofabrication, potentially useful for diverse nanodevices.</P>
Won-Seog Chong,Young-Soo Lee,Young-Jin Kang,Duck-Hyung Lee,Jae-Chun Ryu,Hye Sook Yun-Choi,Ki-Churl Chang 대한생리학회-대한약리학회 1998 The Korean Journal of Physiology & Pharmacology Vol.2 No.3
<P> Tetrahydroisoquinoline (THI) alkaloids can be considered as cyclized derivatives of simple phenylethylamines. Many of them, especially with 6,7-disubstitution, demonstrate a relatively high affinity for catecholamines. Present study examines the pharmacological action of limited series of THI, using rats isolated atria and aorta. In addition, a [<SUP>3</SUP>H] prazosin displacement binding study with THI compounds was performed, using rat brain homogenates to investigate whether these probes have -adrenoceptor affinity. We also compared the vascular relaxation potency of these probes with dobutamine. YS 49, YS 51, higenamine and dobutamine, concentration-dependently, relaxed endothelium-denuded rat thoracic aorta precontracted with phenylephrine (PE, 0.1 ㄍM) in which pEC<SUB>50</SUB> were 5.56⁑0.32 and 5.55⁑0.21, 5.99⁑1.16 and 5.57⁑0.34, respectively. These probes except higenamine also relaxed KCl (65.4 mM)-contracted aorta. In isolated rat atria, all THIs and dobutamine increased heart rate and contractile force. In the presence of propranolol, the concentration response curves of YS 49 and YS 51 shifted to the right and resulted in pA<SUB>2</SUB> values of 8.07⁑0.84 and 7.93⁑0.11, respectively. The slope of each compound was not deviated from unity, indicating that these chemicals are highly competitive at the cardiac -adrenoceptors. YS 49, YS 51, and higenamine showed -adrenoceptor affinity in rat brain, in which the dissociation constant (K<SUB>i</SUB>) was 2.75, 2.81, and 1.02 ㄍM, respectively. It is concluded, therefore, that THI alkaloids have weak affinity to <SUB>1</SUB>-adrenoceptors in rat aorta and brain, respectively, while these probes show relatively high affinity for cardiac -adrenoceptors. Thus, these chemicals may be useful in the treatment of congestive heart failure.
Antioxidant Effects of Isoflavones from the Stem Bark of Cudrania tricuspidata
Lee, Jin-Hwan,Lee, Byong-Won,Kim, Jin-Hyo,Seo, Woo-Duck,Jang, Ki-Chang,Park, Ki-Hun The Korean Society for Applied Biological Chemistr 2005 Journal of Applied Biological Chemistry (J. Appl. Vol.48 No.4
Isoflavones 4'-O-methylalpinumisoflavone (1) and 5, 7, 4'-trihydroxy-6,8-diprenylisoflavone (2) were isolated from stem bark of Cudrania tricuspidata (Carr.) Bureau. These compounds were the first reported from this plant. Antioxidant activities 1 and 2 were evaluated by measuring their ability to scavenge DPPH and ABTS radicals. Diprenylisoflavone 2 showed strong scavenging activity against ABTS ($IC_{50}\;=\;16.3\;{\mu}M$), three-fold higher compared to genistein, which do not possess prenylated group which indicates strong scavenging activity against ABTS radical of isoflavone 2 was due to prenyl group.