Yujeong Lee

Histologic diagnosis based on forceps biopsy is not adequate for determining endoscopic treatment of gastric adenomatous lesions.

BACKGROUND AND STUDY AIMSnControversy persists around the treatment of gastric low-grade dysplasia (LGD). The aim of this study was to investigate possible indications for the endoscopic resection of gastric LGD through analysis of the histologic discrepancies between specimens of gastric LGD obtained by forceps biopsy and by endoscopic mucosal resection (EMR), and of their clinicopathologic characteristics.nnnPATIENTS AND METHODSnThe study involved 293 gastric LGD that were histologically proven on the basis of forceps biopsy in Severance Hospital between January 2004 and December 2007. Twenty cases were regularly followed up, and the remaining 273 were resected by EMR. We performed univariate and multivariate analyses of clinical and endoscopic characteristics including lesion size, number of biopsy fragments, and endoscopic appearance, in order to analyze the factors affecting histologic discrepancies.nnnRESULTSnOf the 273 lesions resected by EMR, 207 (75.8 %) showed concordant histology, whereas for 51 (18.7 %) the histology was upgraded after endoscopic resection. Lesion size, absence of whitish discoloration, and the presence of spontaneous bleeding were found by univariate analysis to be statistically significant factors predicting an upgraded histology after EMR ( P = 0.026, P < 0.001, and P = 0.025, respectively). Multivariate analysis also showed absence of whitish discoloration to be a statistically significant factor influencing histologic discrepancies ( P = 0.001, odds ratio 5.29, 95 % confidence interval 1.95 - 14.37). Perforation and bleeding rates associated with EMR for LGD were 0.7 % and 6.2 %, respectively. Twenty patients who did not undergo EMR were followed up for a mean of 22 months, and 3 were revealed to have adenocarcinoma and 1 high-grade dysplasia on the latest histologic exam.nnnCONCLUSIONSnWe should consider endoscopic resection for gastric LGD that are 2 cm or more in size and do not have whitish discoloration.

Flexible and highly efficient perovskite solar cells with a large active area incorporating cobalt-doped poly(3-hexylthiophene) for enhanced open-circuit voltage

Poly(3-hexylthiophene) (P3HT) is a promising p-type polymer to optimize the architecture, charge transfer, and environmental stability in electronic devices. Therefore, it can be a suitable material for a hole transporting layer in lead halide perovskite solar cells (PSCs). However, the mismatch of band alignment with perovskites suppresses efficient charge extraction and transfer. This results in the significant loss of open-circuit voltage (Voc) and resultant device performance deterioration. Therefore, modifying the energy level is essential to improve band alignment with perovskites. Here, a cobalt complex, tris(2-(1H-pyrazol-1-yl)pyridine) cobalt(II) di[bis(trifluoromethane)sulfonimide] (Co(II)-TFSI) is used as a p-dopant in P3HT. This enhances the conductivity and leads to a downward shift of the energy levels. The efficient charge extraction and transfer from perovskite considerably improves the device performance, resulting in a power conversion efficiency (PCE) of 16.28% and Voc of 1.061 V. Moreover, a flexible device incorporating Co-P3HT exhibits impressive 11.84% PCE and mechanical stability up to 600 bending cycles. And the flexible Co-P3HT device shows better air stability than the Li-doped P3HT (Li-P3HT) device for 40 days. These results suggest that Co(II)-TFSI is an alternative to Li salts to realize high performance in PSCs incorporating polythiophene derivatives.

Epitaxially Grown Ferroelectric PVDF-TrFE Film on Shape-Tailored Semiconducting Rubrene Single Crystal

Epitaxial crystallization of thin poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) films is important for the full utilization of their ferroelectric properties. Epitaxy can offer a route for maximizing the degree of crystallinity with the effective orientation of the crystals with respect to the electric field. Despite various approaches for the epitaxial control of the crystalline structure of PVDF-TrFE, its epitaxy on a semiconductor is yet to be accomplished. Herein, the epitaxial growth of PVDF-TrFE crystals on a single-crystalline organic semiconductor rubrene grown via physical vapor deposition is presented. The epitaxy results in polymer crystals globally ordered with specific crystal orientations dictated by the epitaxial relation between the polymer and rubrene crystal. The lattice matching between the c-axis of PVDF-TrFE crystals and the (210) plane of orthorhombic rubrene crystals develops two degenerate crystal orientations of the PVDF-TrFE crystalline lamellae aligned nearly perpendicular to each other. Thin PVDF-TrFE films with epitaxially grown crystals are incorporated into metal/ferroelectric polymer/metal and metal/ferroelectric polymer/semiconductor/metal capacitors, which exhibit excellent nonvolatile polarization and capacitance behavior, respectively. Furthermore, combined with a printing technique for micropatterning rubrene single crystals, the epitaxy of a PVDF-TrFE film is formed selectively on the patterned rubrene with characteristic epitaxial crystal orientation over a large area.

Surface functionalized nanostructures: Via position registered supramolecular polymer assembly

Versatile control of cylindrical nanostructures formed by supramolecular assembly of end-functionalized polymer blends is demonstrated not only in their orientation over large areas but also in their surface chemical functionalities. Two binary blends consisting of supramolecular analogues of diblock copolymers with complementary end-sulfonated and aminated groups are investigated, viz., mono-end-functionalized polymers of (i) one-end-sulfonated polystyrene (SPS) and one-end-aminated poly(butadiene) (APBD) and (ii) one end-aminated polystyrene (APS) and one end-sulfonated poly(butadiene) (SPBD). The orientation of the cylinders with respect to the substrate surface depends on the solvent annealing time; either hexagonally ordered vertical cylinders or in-plane ones are readily obtained by controlling the solvent annealing time. Selective chemical etching of one of the polymers provides four different chemically modified nanostructures, viz., hexagonally ordered cylindrical holes and cylindrical posts with either sulfonate or amine surface functional groups. Additional supramolecular assembly is successfully achieved by solution coating either polymers or organic dyes that complementarily interact with the functional groups on the nanostructures. Furthermore, the supramolecularly assembled nanostructures are controlled by confining them to topographically pre-patterned Si substrates with pattern geometries of various shapes and sizes to produce globally ordered vertical or in-plane cylinders with chemical functionalities on their surfaces.

P20.01: The influence of large uterine myoma on pregnancy outcome

Objectives: Uterine myomas are benign disease observed in 2 to 3% of all normal pregnancies. The aim of this study is to assess the influence of large uterine myomas on obstetric outcome. Methods: Sixty nine pregnant women with large uterine myoma (8 cm or greater) identified by second trimester ultrasound scans (Accuvix XQ, Medison Co., Seoul, Korea) who delivered at Yonsei University Health System between January 2005 and March 2011 were enrolled. If more than one myoma was detected, the largest one was considered to be representative. The number, size, position, and location of the uterine myomas and the perinatal complications were analyzed. Results: The women were 33.1 ± 3.9 years of age and delivered infants, weighing 3098 ± 600 g at 36.6 ± 5.6 weeks of gestation. Intrauterine fetal deaths at second trimester were noted in two cases. Three pregnancies terminated between 16 and 20 weeks due to preterm premature rupture of membranes, incompetent cervix, and intrauterine fetal death resulted in postpartum hemorrhage caused by retaind placenta. Acute pain localized at myoma site requiring analgesics occurred in 9 (13%) of the women at 17–22 weeks. The fibroids located at uterine fundus were highly associated with the pain symptom (P < 0.05). Preterm labor showed in 12 (17.4%) cases, 50% of which led to preterm delivery. A Cesarean section was performed in 65% of the pregnancies with vertical uterine incision in 11% thereof. Intraoperative bleeding amount was 726 ± 289 ml. The size of the fibroids remained unchanged during pregnancy in most cases. Conclusions: Large uterine myoma may cause abdominal pain, preterm delivery, high rate of cesarean section, intrauterine fetal death and postpartum hemorrhage. However, the neonatal outcome was not adversely affected by large myoma during pregnancy.