ABSTRACT
Purpose@#The aim of this study was to investigate the oncologic safety and identify potential candidates for proximal gastrectomy (PG) in upper third advanced gastric cancer (AGC) and esophagogastric junction (EGJ) cancers. @*Materials and Methods@#Among 5,665 patients who underwent gastrectomy for gastric adenocarcinoma between January 2011 and December 2017, 327 patients who underwent total gastrectomy with standard lymph node (LN) dissection for upper third AGC and Siewert type II EGJ cancers were enrolled. We analyzed the correlation between the metastatic rates of distal LNs (No. 4d, 5, 6, and 12a) around the lower part of the stomach and the clinicopathological characteristics. We identified subgroups with no metastasis to the distal LNs. @*Results@#The metastatic rate of distal LNs in proximal AGC and Siewert type II EGJ cancers was 7.0% (23 of 327 patients). On multivariate analysis, pathological T stage (P=0.001), tumor size (P=0.043), and middle third invasion (P=0.003) were significantly associated with distal LN metastases. Pathological ‘T2 stage’ (n=88), or ‘T3 stage with ≤5 cm tumor size’ (n=87) showed no metastasis in distal LNs, regardless of middle third invasion. Pathological T3 stage with tumor size > 5 cm (n=61) and T4 stage (n=91) had metastasis in the distal LNs. @*Conclusions@#In the upper third AGC and Siewert type II EGJ cancer, pathological T2 and small-sized T3 stage groups are possible candidates for PG in cases without distal LN metastasis. Further validation studies are required for clinical application.
ABSTRACT
Mt. Paektu (also known as Changbaishan) is an enigmatic volcano on the border between the Democratic People's Republic of Korea (DPRK) and China. Despite being responsible for one of the largest eruptions in history, comparatively little is known about its magmatic evolution, geochronology, or underlying structure. We present receiver function results from an unprecedented seismic deployment in the DPRK. These are the first estimates of the crustal structure on the DPRK side of the volcano and, indeed, for anywhere beneath the DPRK. The crust 60 km from the volcano has a thickness of 35 km and a bulk V P/V S of 1.76, similar to that of the Sino-Korean craton. The V P/V S ratio increases ~20 km from the volcano, rising to >1.87 directly beneath the volcano. This shows that a large region of the crust has been modified by magmatism associated with the volcanism. Such high values of V P/V S suggest that partial melt is present in the crust beneath Mt. Paektu. This region of melt represents a potential source for magmas erupted in the last few thousand years and may be associated with an episode of volcanic unrest observed between 2002 and 2005.
Subject(s)
Volcanic Eruptions , Democratic People's Republic of Korea , Disasters , History, Ancient , HumansABSTRACT
Inverse opal (IO) films of tin dioxide (SnO2) were fabricated on polystyrene (PS) beads (diameter=350 nm (±20 nm) with a spin coating method. To compensate for the large band gap (Eg=3.8 eV), a thin TiO2 shell was deposited on the SnO2-IO films with atomic layer deposition (ALD), which produced shells with thicknesses of 10-40 nm. The morphological changes and crystalline properties of the SnO2 and TiO2-coated SnO2 (herein after referred to as TiO2/SnO2) IO films were investigated with field-emission scanning electron microscopy and X-ray diffraction, respectively. The photoelectrochemical (PEC) behavior of the samples was tested in a 0.1 M KOH solution under 1 sun illumination (100 mW/cm2 with an AM 1.5 filter). The highest PEC performance was obtained with the TiO2(10 nm)/SnO2 IO films, which produced a photocurrent density (Jsc) of 4.67 mA/cm2 at 0.5 V (vs NHE) and was sequentially followed by the TiO2(20 nm)/SnO2-IO, TiO2(30 nm)/SnO2-IO, TiO2 (40 nm)/SnO2-IO and SnO2 IO films. Overall, the thin TiO2 shell covered on the SnO2-IO core enhanced Jsc by 3 orders of magnitude, which in turn the PEC activity. This is mainly ascribed to the extremely low charge-transfer resistance (Rct) in the photoelectrode/electrolyte and at the TiO2/SnO2 interface, as well as the contribution of the photoactive TiO2 layer, which has an Eg of 3.2 eV. Moreover, to improve the electrical conductivity of the core SnO2 IO film, the films were doped with 10 mol % of F. The F- doped films were labeled as the FTO IO film. The Rct of the FTO-IO films decreased because of the improved electronic conductivity, enhancing the PEC performance of the TiO2(10 nm)/FTO-IO films by approximately 20%. The core-shell nanowire mesh nanoarchitecture is therefore suggested to provide an insight for designing the peculiar structure based on the material's properties and the engineering of their band gap energy for highly efficient PEC performance.
