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Shin SW, Cho JE, Lee HM, Park JS, Kang SJ. Photoresponses of InSnGaO and InGaZnO thin-film transistors. RSC Adv 2016. [DOI: 10.1039/c6ra17896k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
ITGO TFT were fabricated to study the photoresponses of indium-based oxide semiconductors. We found that the increased amount and low electron binding energy of indium can improve the recovery time of ITGO TFTs.
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Kim A, Lee M, Han S, Kang SJ, Song K. Raman Spectroscopic Studies of Doped Graphene. POLYMER KOREA 2015. [DOI: 10.7317/pk.2015.39.6.956] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Shin SW, Lee KH, Park JS, Kang SJ. Highly Transparent, Visible-Light Photodetector Based on Oxide Semiconductors and Quantum Dots. ACS APPLIED MATERIALS & INTERFACES 2015; 7:19666-71. [PMID: 26293387 DOI: 10.1021/acsami.5b04683] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Highly transparent phototransistors that can detect visible light have been fabricated by combining indium-gallium-zinc oxide (IGZO) and quantum dots (QDs). A wide-band-gap IGZO film was used as a transparent semiconducting channel, while small-band-gap QDs were adopted to absorb and convert visible light to an electrical signal. Typical IGZO thin-film transistors (TFTs) did not show a photocurrent with illumination of visible light. However, IGZO TFTs decorated with QDs showed enhanced photocurrent upon exposure to visible light. The device showed a responsivity of 1.35×10(4) A/W and an external quantum efficiency of 2.59×10(4) under illumination by a 635 nm laser. The origin of the increased photocurrent in the visible light was the small band gap of the QDs combined with the transparent IGZO films. Therefore, transparent phototransistors based on IGZO and QDs were fabricated and characterized in detail. The result is relevant for the development of highly transparent photodetectors that can detect visible light.
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Lee YK, Lee TS, Song IH, Jeong HY, Kang SJ, Kim MW, Ryu SH, Jung IH, Kim JS, Park YS. Inhibition of pulmonary cancer progression by epidermal growth factor receptor-targeted transfection with Bcl-2 and survivin siRNAs. Cancer Gene Ther 2015; 22:335-43. [DOI: 10.1038/cgt.2015.18] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/26/2015] [Accepted: 02/27/2015] [Indexed: 01/20/2023]
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Cha MJ, Kim SM, Kang SJ, Seo JH, Walker B. Improved performance in flexible organic solar cells via optimization of highly transparent silver grid/graphene electrodes. RSC Adv 2015. [DOI: 10.1039/c5ra10838a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Organic solar cells were fabricated on polyethylene terephthalate (PET) substrates using hybrid silver grid/graphene films as transparent conducting electrodes and the effect of the silver grid dimensions was characterized.
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Sung HH, Choo SH, Ko M, Kang SJ, Chae MR, Kam SC, Han DH, So I, Lee SW. Increased expression of TRPC4 channels associated with erectile dysfunction in diabetes. Andrology 2014; 2:550-8. [PMID: 24782410 DOI: 10.1111/j.2047-2927.2014.00214.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 03/09/2014] [Accepted: 03/15/2014] [Indexed: 11/27/2022]
Abstract
In recent reports, an association between altered TRPC channel function and the development of various diabetic complications has drawn the attention of many investigators. The aim of this study was to investigate the expression of TRPC4 channels of corpus smooth muscle (CSM) cells in diabetes, and to evaluate the association between erectile dysfunction (ED) and altered TRPC4 channel function. The expression of TRPC4 in the penile tissue of human, normal and diabetic rat was investigated using RT-PCR, western blotting and immunohistochemistry (IHC). In vivo gene transfer of dominant negative (DN) TRPC4 into the CSM of rat was conducted. In vivo pelvic nerve stimulation was performed to measure erectile function. Expression of TRPC1, TRPC3, TRPC4 and TRPC6 in human and rat CSM tissues was confirmed by RT-PCR, western blot and IHC. In the diabetic rat, the expression levels of mRNA and protein of the TRPC4, and TRPC6 were significantly increased compared to control rats (p < 0.05). The change in TRPC4 expression in the diabetic rats was higher than those of the other TRPC subunits (p < 0.05). The IHC showed that only TRPC4 expression had a higher intensity in the diabetes compared to normal rats (p < 0.05). Gene transfection with TRPC4(DN) into the diabetic rats restored erectile function to levels similar to that of normal controls. Gene expression of TRPC4(DN) in CSM tissue was confirmed by RT-PCR 2 weeks after transfection. This study demonstrated that TRPC4 channel expression increased in the penile CSM cells of diabetic rats. The down-regulation of TRPC4 with DN form restored erectile function in the diabetic rats. The alteration of TRPC4 channel is one of pathophysiology of ED and could be a target for drug development for ED.
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Kim YS, Kang SJ, Kim JW, Cho HR, Moon SB, Kim KY, Lee HS, Han CH, Ku SK, Lee YJ. Effects of Polycan, a β-glucan, on experimental periodontitis and alveolar bone loss in Sprague-Dawley rats. J Periodontal Res 2012; 47:800-10. [PMID: 22780690 DOI: 10.1111/j.1600-0765.2012.01502.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND OBJECTIVE Polycan is a promising candidate for the treatment of periodontal disease. This study was undertaken to examine whether Polycan, a type of β-glucan, has a protective effect on ligature-induced experimental periodontitis and related alveolar bone loss in Sprague-Dawley rats. MATERIAL AND METHODS Polycan was orally administered, daily, for 10 d, at 21.25, 42.5 or 85 mg/kg, beginning 1 d after ligation. Changes in body weight and alveolar bone loss were monitored, and the anti-inflammatory effects of Polycan were determined by measuring the levels of myeloperoxidase (MPO), interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) in gingival tissue. We also evaluated inducible nitric oxide synthase (iNOS) activity and malondialdehyde (MDA) concentrations as a measure of the antioxidant effect. RESULTS Ligature placement led to a marked decrease in body weight, increased alveolar bone loss and increased concentrations of MPO, IL-1β, TNF-α and MDA, as well as increased iNOS activity and inflammatory cell infiltration and decreased collagen-fiber content. Histological examination revealed increases in the number and activity of osteoclast cells, decreases in alveolar bone volume and elevated percentages of osteclasts on the alveolar bone surface. Daily oral treatment with 42.5 or 85 mg/kg of Polycan for 10 d led to significant, dose-dependent inhibition of the effect of ligature placement. CONCLUSION Taken together, these results suggest that 10 d of oral treatment with Polycan effectively inhibits ligature placement-induced periodontitis and related alveolar bone loss via an antioxidant effect.
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Kim JE, Choi KH, Kang SJ, Seo EJ, Park CK, Cho BK, Kang H. Angiosarcoma mimicking cutis verticis gyrata. Clin Exp Dermatol 2011; 36:806-8. [PMID: 21507034 DOI: 10.1111/j.1365-2230.2011.04059.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kang JH, Choi NK, Kang SJ, Yang SY, Ko HM, Jung JY, Kim MS, Koh JT, Kim WJ, Oh WM, Kim BY, Kim SH. Alendronate affects cartilage resorption by regulating vascular endothelial growth factor expression in rats. Anat Rec (Hoboken) 2010; 293:786-93. [PMID: 20432372 DOI: 10.1002/ar.21092] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study was performed to determine effects of alendronate on the tibial proximal epiphyseal cartilage undergoing endochondral ossification and the expression of vascular endothelial growth factor (VEGF) from the cartilage. Alendronate was injected subcutaneously every other day in postnatal Day 1 Sprague Dawley rats. The rats were sacrificed 3, 5, 7, and 10 days after the first injection. The effect of alendronate treatment for 10 days was demonstrated from the morphological change that the area of the secondary ossification center in the epiphysis was significantly smaller in the alendronate group than that in the control group (P < 0.05). Strong immunoreactivity to VEGF was observed in the hypertrophied chondrocytes and some proliferating chondrocytes in the epiphyseal cartilage at postnatal Day 5 and was decreased after the alendronate treatment for 5 days. Immunoreactivity was observed in not only hypertrophied cells but also the peripheral cartilaginous matrix adjacent to the vascular canals invading into the central portion of the cartilage at postnatal Day 7. This reactivity was also reduced considerably by the alendronate treatment for 7 days. The level of VEGF expression was reduced by the alendronate treatment at both the transcription and translation levels. However, the transcriptional level of the flt-1 and flk-1 receptors was relatively unaltered by the treatment. These results suggest that VEGF expression is required for vascular invasion into the developing cartilage and alendronate can affect its resorption by downregulating VEGF expression.
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Kim YK, Chin JH, Kang SJ, Jun IG, Song JG, Jeong SM, Park JY, Hwang GS. Association between central venous pressure and blood loss during hepatic resection in 984 living donors. Acta Anaesthesiol Scand 2009; 53:601-6. [PMID: 19419353 DOI: 10.1111/j.1399-6576.2009.01920.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Although low central venous pressure (CVP) anesthesia has been used to minimize blood loss during hepatectomy, the efficacy of this technique remains controversial. We therefore assessed the association between blood loss and CVP during hepatic resection, and examined significant determinants associated with intraoperative hemorrhage during hepatectomy in living donors. METHODS Between April 2004 and April 2008, 984 living donors who underwent a hepatic resection were assessed retrospectively. Univariate and multivariate analyses were performed to explore the relationships between intraoperative blood loss and several variables including CVP. RESULTS The mean intraoperative blood loss was 691.3 +/- 365.5 ml. Only four donors required packed red blood cell transfusions (mean, 1.5 U). The mean duration of hepatic resection was 92.1 +/- 26.3 min. The mean, maximum, and minimum values of CVP measured during hepatectomy were 4.6 +/- 1.7, 5.3 +/- 1.8, and 4.0 +/- 1.8 mmHg, respectively, and were not significantly correlated with intraoperative blood loss. On multivariate analysis, predictors of hemorrhage were liver fatty change, gender, and body weight, but none of the mean CVP, surgeons, anesthesiologists, anesthesia duration, resected liver volume, hepatectomy type, systolic blood pressure, heart rate, or body temperature were significant. CONCLUSIONS CVP during hepatic resection was not associated with intraoperative blood loss in living liver donors, suggesting that CVP may not be an important factor in predicting blood loss during hepatectomy in healthy subjects.
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Singh SR, Grossniklaus HE, Kang SJ, Edelhauser HF, Ambati BK, Kompella UB. Intravenous transferrin, RGD peptide and dual-targeted nanoparticles enhance anti-VEGF intraceptor gene delivery to laser-induced CNV. Gene Ther 2009; 16:645-59. [PMID: 19194480 DOI: 10.1038/gt.2008.185] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Choroidal neovascularization (CNV) leads to loss of vision in age-related macular degeneration (AMD), the leading cause of blindness in adult population over 50 years old. In this study, we developed intravenously administered, nanoparticulate, targeted nonviral retinal gene delivery systems for the management of CNV. CNV was induced in Brown Norway rats using a 532 nm laser. We engineered transferrin, arginine-glycine-aspartic acid (RGD) peptide or dual-functionalized poly-(lactide-co-glycolide) nanoparticles to target delivery of anti-vascular endothelial growth factor (VEGF) intraceptor plasmid to CNV lesions. Anti-VEGF intraceptor is the only intracellularly acting VEGF inhibitory modality. The results of the study show that nanoparticles allow targeted delivery to the neovascular eye but not the control eye on intravenous administration. Functionalizing the nanoparticle surface with transferrin, a linear RGD peptide or both increased the retinal delivery of nanoparticles and subsequently the intraceptor gene expression in retinal vascular endothelial cells, photoreceptor outer segments and retinal pigment epithelial cells when compared to nonfunctionalized nanoparticles. Most significantly, the CNV areas were significantly smaller in rats treated with functionalized nanoparticles as compared to the ones treated with vehicle or nonfunctionalized nanoparticles. Thus, surface-functionalized nanoparticles allow targeted gene delivery to the neovascular eye on intravenous administration and inhibit the progression of laser-induced CNV in a rodent model.
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Moon SY, Lee BH, Seo SW, Kang SJ, Na DL. Slow vertical saccades in the frontotemporal dementia with motor neuron disease. J Neurol 2008; 255:1337-43. [PMID: 18825435 DOI: 10.1007/s00415-008-0890-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Revised: 12/10/2007] [Accepted: 02/01/2008] [Indexed: 02/02/2023]
Abstract
BACKGROUND Ocular motor abnormalities play an important role in differential diagnoses of Pick complex diseases. OBJECTIVES We evaluated how frequently supranuclear vertical saccadic impairment was observed in patients with frontotemporal dementia with motor neuron disease (FTD-MND). In addition, we tried to characterize their vertical saccadic abnormalities. MATERIALS AND METHODS Eleven patients with FTD-MND were recruited. Supranuclear vertical saccadic impairment on gross examination was defined as slow saccades with or without reduction in the final amplitude of the movement accompanied by intact oculocephalic reflex. We also recorded their saccades in 6 out of 11 patients using 2-dimensional videooculography (VOG). We measured the amplitude and peak velocity of each saccade. RESULTS On bedside examination, supranuclear vertical saccadic impairment was observed in 9 of 11 patients. One of the two remaining patients could not be evaluated due to poor cooperation and the other showed normal saccades. Five of nine patients with ocular abnormalities and one patient with normal saccade on gross examination underwent the VOG studies. The results showed that all the five patients with gross ocular abnormalities, compared with age-matched controls, had slowing of vertical saccades. Three out of five patients also showed slowing even in the large horizontal saccades. CONCLUSIONS Our results showed that slow vertical saccades are common in FTDMND. FTD-MND could be another disease that affects vertical gaze among Pick complex disease. Future pathologic studies are needed to confirm the involvement of the burst neurons in the dorsal midbrain in patients with FTDMND.
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Khan MA, Lee HJ, Lee WS, Kim HS, Ki KS, Hur TY, Suh GH, Kang SJ, Choi YJ. Structural growth, rumen development, and metabolic and immune responses of Holstein male calves fed milk through step-down and conventional methods. J Dairy Sci 2007; 90:3376-87. [PMID: 17582123 DOI: 10.3168/jds.2007-0104] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Structural growth, feed consumption, rumen development, metabolic response, and immune response were studied in Holstein calves fed milk through either a conventional method or a step-down (STEP) method. In the conventional method, calves (n = 20) were fed colostrum and then milk at a rate of 10% of their BW for the entire period of 44 d. In the STEP method, calves (n = 20) were given colostrum and then milk at a rate of 20% of their BW for 23 d, which was reduced (between d 24 to 28) to 10% of their BW for the remaining 16 d. The calves on both methods were weaned gradually by diluting milk with water between d 45 and 49. After weaning, feed consumption, structural growth, and body weight gain were monitored until calves were 63 d of age. At d 63, twelve calves (6/treatment) were euthanized and rumen papillae length, papillae width, rumen wall thickness, and emptied forestomach weight were recorded. At wk 4, 7, and 9, ruminal contents were collected to enumerate rumen metabolites. The STEP-fed calves consumed a greater amount of milk than conventionally fed calves during the pre-STEP (d 1 to 28), post-STEP (d 29 to 49), and preweaning (d 1 to 49) periods. Consumption of starter and hay was greater during the pre-STEP period and lesser during the post-STEP and postweaning (d 50 to 63) periods in calves on the conventional method than on the STEP method. Body weight gain and structural growth measurements of calves were greater on the STEP method than on the conventional method. A hypophagic condition caused by greater milk consumption depressed solid feed intake of STEP-fed calves during the pre-STEP period, and a hyperphagic response caused by a reduced nutrient supply from milk triggered their consumption of solid feed during the post-STEP and postweaning periods. Ruminal pH and concentrations of ammonia, total volatile fatty acids, acetate, propionate, butyrate, and plasma beta-hydroxybutyrate were higher in calves on the STEP method and at weaning and postweaning (d 63) were lower in calves on the conventional method. Emptied weight of the forestomach, rumen wall thickness, papillae length, papillae width, and papillae concentration were higher in calves on the STEP method than in those on the conventional method. Blood glucose was lower, and blood urea nitrogen and beta-hydroxybutyrate at weaning and postweaning were higher in STEP-fed calves. Serum IgG, IgA, and triglycerides for 1, 2, and 3 wk of age were higher in calves on the STEP method than in those on the conventional method. In conclusion, greater feed consumption, BW gain, and structural growth, and a more metabolically and physically developed rumen were observed in calves on the STEP method than in those on the conventional method.
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Kang SJ, Kocabas C, Kim HS, Cao Q, Meitl MA, Khang DY, Rogers JA. Printed multilayer superstructures of aligned single-walled carbon nanotubes for electronic applications. NANO LETTERS 2007; 7:3343-8. [PMID: 17935374 DOI: 10.1021/nl071596s] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We developed means to form multilayer superstructures of large collections of single-walled carbon nanotubes (SWNTs) configured in horizontally aligned arrays, random networks, and complex geometries of arrays and networks on a wide range of substrates. The approach involves guided growth of SWNTs on crystalline and amorphous substrates followed by sequential, multiple step transfer of the resulting collections of tubes to target substrates, such as high-k thin dielectrics on silicon wafers, transparent plates of glass, cylindrical tubes and other curved surfaces, and thin, flexible sheets of plastic. Electrical measurements on dense, bilayer superstructures, including crossbars, random networks, and aligned arrays on networks of SWNTs reveal some important characteristics of representative systems. These and other layouts of SWNTs might find applications not only in electronics but also in areas such as optoelectronics, sensors, nanomechanical systems, and microfluidics.
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Park JU, Hardy M, Kang SJ, Barton K, Adair K, Mukhopadhyay DK, Lee CY, Strano MS, Alleyne AG, Georgiadis JG, Ferreira PM, Rogers JA. High-resolution electrohydrodynamic jet printing. NATURE MATERIALS 2007; 6:782-9. [PMID: 17676047 DOI: 10.1038/nmat1974] [Citation(s) in RCA: 481] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Accepted: 06/21/2007] [Indexed: 05/16/2023]
Abstract
Efforts to adapt and extend graphic arts printing techniques for demanding device applications in electronics, biotechnology and microelectromechanical systems have grown rapidly in recent years. Here, we describe the use of electrohydrodynamically induced fluid flows through fine microcapillary nozzles for jet printing of patterns and functional devices with submicrometre resolution. Key aspects of the physics of this approach, which has some features in common with related but comparatively low-resolution techniques for graphic arts, are revealed through direct high-speed imaging of the droplet formation processes. Printing of complex patterns of inks, ranging from insulating and conducting polymers, to solution suspensions of silicon nanoparticles and rods, to single-walled carbon nanotubes, using integrated computer-controlled printer systems illustrates some of the capabilities. High-resolution printed metal interconnects, electrodes and probing pads for representative circuit patterns and functional transistors with critical dimensions as small as 1 mum demonstrate potential applications in printed electronics.
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Kang SJ, Schmack I, Benson HE, Grossniklaus HE. Histopathological findings in postmortem eyes after photodynamic therapy for choroidal neovascularisation in age-related macular degeneration: report of two cases. Br J Ophthalmol 2007; 91:1602-6. [PMID: 17567659 PMCID: PMC2095496 DOI: 10.1136/bjo.2007.121830] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND To report the histopathological findings after photodynamic therapy (PDT) in eyes obtained postmortem with choroidal neovascularisation (CNV) secondary to age-related macular degeneration (AMD). METHODS Two eyes were obtained postmortem from two patients with CNV secondary to AMD. Both of the patients had been treated with PDT. Serial sections through the posterior poles were obtained and stained with haematoxylin-eosin, periodic acid-Schiff, Masson trichrome or phosphotungstic acid haematoxylin (PTAH). Two-dimensional reconstructions were prepared and compared with fluorescein angiograms. RESULTS The interval between PDT and death was 3 months and 17 months in each patient, respectively. Light-microscopic examination showed that CNV enveloped with retinal pigment epithelium (RPE) in both eyes. The average size of the CNV was 550 x 280 microm. One eye had combined (subRPE/subretinal) growth pattern CNV, and the other eye had both type I (subRPE) and combined growth pattern CNV. All specimens contained fibrous proliferation and patent vascular channels within the CNV, and there was no thrombus formation within the vascular channels. No apparent abnormalities in the choroid were observed by light microscopy. CONCLUSIONS Although involution with fibrous tissue proliferation occurred, PDT did not result in permanent occlusion of the vascular channels in the CNV. Our findings indicate that PDT may accelerate involution of CNV, thus limiting its size and preserving photoreceptors.
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Kocabas C, Pimparkar N, Yesilyurt O, Kang SJ, Alam MA, Rogers JA. Experimental and theoretical studies of transport through large scale, partially aligned arrays of single-walled carbon nanotubes in thin film type transistors. NANO LETTERS 2007; 7:1195-202. [PMID: 17394371 DOI: 10.1021/nl062907m] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Gate-modulated transport through partially aligned films of single-walled carbon nanotubes (SWNTs) in thin film type transistor structures are studied experimentally and theoretically. Measurements are reported on SWNTs grown by chemical vapor deposition with systematically varying degrees of alignment and coverage in transistors with a range of channel lengths and orientations perpendicular and parallel to the direction of alignment. A first principles stick-percolation-based transport model provides a simple, yet quantitative framework to interpret the sometimes counterintuitive transport parameters measured in these devices. The results highlight, for example, the dramatic influence of small degrees of SWNT misalignment on transistor performance and imply that coverage and alignment are correlated phenomena and therefore should be simultaneously optimized. The transport characteristics reflect heterogeneity in the underlying anisotropic metal-semiconductor stick-percolating network and cannot be reproduced by classical transport models.
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Kang SJ, Kim SH, Liu P, Jovel E, Towers GHN. Antibacterial activities of some mosses including Hylocomium splendens from South Western British Columbia. Fitoterapia 2007; 78:373-6. [PMID: 17553633 DOI: 10.1016/j.fitote.2007.03.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Accepted: 03/05/2007] [Indexed: 11/17/2022]
Abstract
The antibacterial activity of methanol extracts of ten moss species and fractions prepared from 80% methanol extract of Hylocomium splendens were evaluated by disk diffusion method. Nine moss species showed antibacterial activity against Gram (+) bacteria, in particular H. splendens and its ethyl acetate fractions showed stronger activity. Enhancement of antibacterial activity against Staphylococci by UV-A light irradiation was demonstrated in the extracts of Bartramia pomiformis, Ceratodon purpureus and Neckera douglasii.
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Tomkinson GR, Olds TS, Kang SJ, Kim DY. Secular Trends in the Aerobic Fitness Test Performance and Body Mass Index of Korean Children and Adolescents (1968 - 2000). Int J Sports Med 2007; 28:314-20. [PMID: 17024618 DOI: 10.1055/s-2006-924357] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
There is increasing evidence that the aerobic fitness performance of children is declining, at least in developed countries. To see if there was evidence of similar trends in a non-Western country, this study analysed data on 6-18-year-old Koreans tested between 1968 and 2000 using distance runs ranging from 600 to 1200 m. All existing data on the results of children's aerobic fitness tests in Korea were collated. In addition to six individual studies, very large datasets were available from the Korean Ministries of Education, and the Ministry of Culture and Tourism. Data on a total of 22,127,265 6-18-year-old children were available in the form of group means and standard deviations. Data were collated for each age x sex x test group, and performances were expressed as percentages of the fitted values for the year 1992 to standardise across tests, ages and sexes. All age x sex x test groups were then combined, and curves were fitted using weighted regression. A two-linear segment model best described the pattern of change (r = 0.83, p < 0.001). There was a relatively slow decline (0.26 % per year) in the aerobic performance of Korean children between 1968 and 1984. After 1984, however, there was a steep decline in performance, averaging 0.80 % per year. The rate of decline was greater in boys, younger children and children from outside the capital Seoul. Changes in running performance showed a similar pattern to changes in estimated body mass index. Compared to other countries, there has been a sharp decline in Korean children's performance on tests of aerobic fitness, which has been concurrent with increases in estimated body mass index.
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Kang SJ, Kocabas C, Ozel T, Shim M, Pimparkar N, Alam MA, Rotkin SV, Rogers JA. High-performance electronics using dense, perfectly aligned arrays of single-walled carbon nanotubes. NATURE NANOTECHNOLOGY 2007; 2:230-6. [PMID: 18654268 DOI: 10.1038/nnano.2007.77] [Citation(s) in RCA: 385] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2006] [Accepted: 02/23/2007] [Indexed: 05/17/2023]
Abstract
Single-walled carbon nanotubes (SWNTs) have many exceptional electronic properties. Realizing the full potential of SWNTs in realistic electronic systems requires a scalable approach to device and circuit integration. We report the use of dense, perfectly aligned arrays of long, perfectly linear SWNTs as an effective thin-film semiconductor suitable for integration into transistors and other classes of electronic devices. The large number of SWNTs enable excellent device-level performance characteristics and good device-to-device uniformity, even with SWNTs that are electronically heterogeneous. Measurements on p- and n-channel transistors that involve as many as approximately 2,100 SWNTs reveal device-level mobilities and scaled transconductances approaching approximately 1,000 cm(2) V(-1) s(-1) and approximately 3,000 S m(-1), respectively, and with current outputs of up to approximately 1 A in devices that use interdigitated electrodes. PMOS and CMOS logic gates and mechanically flexible transistors on plastic provide examples of devices that can be formed with this approach. Collectively, these results may represent a route to large-scale integrated nanotube electronics.
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Seo JH, Kim CY, Kang SJ, Yoo KH, Whang CN, Moewes A, Chang GS. Electronic structure of NPB and BCP molecules probed by x-ray emission spectroscopy. J Chem Phys 2007; 126:064706. [PMID: 17313237 DOI: 10.1063/1.2464086] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Soft x-ray absorption and emission spectroscopies have been employed to investigate the electronic structure and chemical bonding of two prototypical molecules, N,N(')-bis-(1-naphthyl)-N,N(')-diphenyl-1,1(')-biphenyl-4,4(')-diamine (NPB) and bathocuproine (BCP), which are frequently chosen because of their hole-transporting and hole-blocking properties, respectively. The resulting resonant C Kalpha x-ray emission spectra of these materials reveal different spectral features depending on the resonant excitation energy. According to the N absorption and emission spectra, the contribution of N atoms to the highest occupied and lowest unoccupied molecular orbitals is different for in NPB and in BCP. Detailed knowledge of these materials will allow tailoring charge transport properties of organic devices in order to develop high performance organic light-emitting diodes and photovoltaic cells.
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Ahn JH, Kim HS, Lee KJ, Jeon S, Kang SJ, Sun Y, Nuzzo RG, Rogers JA. Heterogeneous three-dimensional electronics by use of printed semiconductor nanomaterials. Science 2006; 314:1754-7. [PMID: 17170298 DOI: 10.1126/science.1132394] [Citation(s) in RCA: 290] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We developed a simple approach to combine broad classes of dissimilar materials into heterogeneously integrated electronic systems with two- or three-dimensional layouts. The process begins with the synthesis of different semiconductor nanomaterials, such as single-walled carbon nanotubes and single-crystal micro- and nanoscale wires and ribbons of gallium nitride, silicon, and gallium arsenide on separate substrates. Repeated application of an additive, transfer printing process that uses soft stamps with these substrates as donors, followed by device and interconnect formation, yields high-performance heterogeneously integrated electronics that incorporate any combination of semiconductor nanomaterials on rigid or flexible device substrates. This versatile methodology can produce a wide range of unusual electronic systems that would be impossible to achieve with other techniques.
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Han SA, Chun H, Park CM, Kang SJ, Kim SH, Sohn D, Yun SH, Lee WY. Prognostic Significance of β-catenin in Colorectal Cancer with Liver Metastasis. Clin Oncol (R Coll Radiol) 2006; 18:761-7. [PMID: 17168211 DOI: 10.1016/j.clon.2006.08.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
AIMS A decreased expression of beta-catenin has been known to be associated with tumour metastasis. The prognostic value of beta-catenin expression in colorectal cancer (CRC) patients with liver metastasis was evaluated. MATERIALS AND METHODS Seventy patients who underwent curative resection for CRC with liver metastasis were included. Tissue samples from normal colon mucosa, primary CRC and metastatic liver lesions were prepared in tissue microarrays, and were stained by immunohistochemistry with beta-catenin antibody. The beta-catenin expression of primary CRC tissues and metastatic liver tissues was analysed. RESULTS A high expression of beta-catenin (score > 6) was observed in 42.0% and 21.9% of primary colorectal tissues and metastatic liver tissues, respectively. The beta-catenin expression in metastatic liver tissues was significantly lower than in primary CRC tissues (P = 0.022). The patients were classified into two groups according to the difference in the beta-catenin expression score between the primary CRC and the liver metastasis. Group A was defined as patients showing a remarkably decreased expression of beta-catenin in their metastatic liver tissue and group B was defined as patients showing a maintained or increased beta-catenin expression in their metastatic liver tissue in comparison with their primary CRC. The overall survival and disease-free survival rates were better in group B than in group A, and this was statistically significant (P = 0.02, P = 0.002). CONCLUSION The decreased expression of beta-catenin in a metastatic liver lesion may be a poor prognostic marker in CRC with liver metastasis and further investigation is necessary.
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Jeong Y, Park KC, Cho SS, Kim EJ, Kang SJ, Kim SE, Kang E, Na DL. Pattern of glucose hypometabolism in frontotemporal dementia with motor neuron disease. Neurology 2005; 64:734-6. [PMID: 15728305 DOI: 10.1212/01.wnl.0000152047.58767.9d] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Frontotemporal dementia (FTD) often coexists with motor neuron disease (MND). To characterize glucose hypometabolism in patients with FTD with MND (FTD/MND), the authors compared the glucose metabolism of 8 patients with FTD/MND with that of 29 patients with FTD. All of the patients with FTD/MND showed glucose hypometabolism only in the frontal area, whereas most patients with FTD had hypometabolism in the frontal and temporal areas. FTD/MND also showed a more symmetric pattern of glucose hypometabolism than FTD.
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Jeong Y, Song YM, Chung PW, Kim EJ, Kang SJ, Kim JM, Cho SS, Kim SE, Byun HS, Na DL. Correlation of ventricular asymmetry with metabolic asymmetry in frontotemporal dementia. J Neuroradiol 2005; 32:247-54. [PMID: 16237363 DOI: 10.1016/s0150-9861(05)83145-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND PURPOSE The clinical presentation of frontotemporal dementia (FTD) is often asymmetrical in terms of both its clinical features and atrophy on MRI. Asymmetry in the lateral ventricle size on structural neuroimaging in FTD patients may have clinical significance. However, this has not been systematically investigated yet. This study compares the ventricular asymmetry seen on MRI with that of the asymmetric glucose metabolism using FDG-PET in patients with FTD. METHODS Nineteen FTD patients who underwent both brain MRI and FDG-PET were retrospectively selected. As control groups, 23 and 11 age and sex-matched healthy normal subjects underwent either brain MRI or FDG-PET, respectively. The ventricular asymmetry index (VAI) was obtained in two ways: by visual rating (VAI-V) and by measuring the lateral ventricular volumes (VAI-ROI). The hemispheric asymmetry of the glucose metabolism on FDG-PET (MAI) was assessed in three ways: 1) by visual rating (MAI-V), 2) by counting the FDG activity of each hemisphere on normalized and smoothed PET images (MAI-ROI) and 3) by counting the number of voxels with significant hypometabolism based on statistical parametric mapping results (MAI-SPM). RESULTS The VAIs on MRI (VAI-V and VAI-ROI) were highly correlated, as were the MAIs (MAI-V, MAI-ROI, and MAI-SPM) on FDG-PET. More importantly, the VAIs on MRI and the MAIs on FDG-PET showed high correlation. CONCLUSIONS Ventricular asymmetry in FTD patients was common (78.9%) and there was a high correlation between the ventricular structural asymmetry and the hemispheric metabolic asymmetry. Therefore, it would be reasonable to interpret that the hemisphere with larger ventricle on MRI in FTD patients is undergoing a more active degenerative process.
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