Regional lymph node recurrence without intragastric lesions after curative endoscopic resection of early gastric cancer meeting the absolute indications of endoscopic resection: A case report.

RATIONALE: With the increase of gastric cancer surveillance and endoscopic resection techniques, the number of endoscopic resections being performed for the treatment of early gastric cancer in East Asian countries has been increasing. Previously, endoscopic resection has been limited to only differentiated type intramucosal cancers which had a diameter ≤2.0 cm, provided there was no evidence of ulceration and lymphovascular invasion, known as absolute indications. And recently, indications for endoscopic resection have been expanded to include even more cases. PATIENT CONCERNS: A 57-year-old female, who had undergone curative endoscopic submucosal dissection for early gastric cancer under the absolute indications for endoscopic resection 5 years prior, was referred to the department of general surgery with metastatic perigastric lymph nodes without intragastric lesions. DIAGNOSIS: Computed tomography scan revealed the presence of a few enlarged lymph nodes at the distal part of the lesser curvature of the stomach. And positron emission tomography scan further revealed the presence of two hypermetabolic lymph nodes near the common hepatic artery, suggestive of metastatic lymph nodes. INTERVENTIONS: Laparoscopic distal gastrectomy and Roux-en-Y gastrojejunostomy with D2 lymph node dissection were performed. OUTCOMES: Final pathology report revealed the absence of any residual carcinoma in the stomach. However lymphovascular invasion of omental fat, and 3 out of 29 perigastric lymph nodes harvested had metastatic adenocarcinoma. LESSONS: The case demonstrates that regional lymph node recurrence without intragastric lesions after curative resection of early gastric cancer meeting the absolute indications for endoscopic resection is possible even 5 years after resection of the primary lesion.

A conducting atomic force microscopy study of conducting filament nanobits in the epitaxial NiO thin film prepared precisely controlled by the oxidation time of the single crystalline Ni substrates.

We report on the formation of conducting filament (CF) nanodots and the resistive random access memory (RRAM) characteristics of epitaxial NiO thin films with good crystallinity obtained by oxidation of the single crystal Ni substrates. The thickness of the epitaxial NiO thin films with good crystallinity was precisely controlled by the oxidation time. The local current mapping using conducting atomic force microscope (CAFM) showed that the NiO thin films had uniform resistance without conducting defects inside. In particular, it was confirmed that CF nanodots with a diameter of several nanometers in the 5-nm-thick NiO thin film and the storage density of about 16.7 Tbit/in2 was achieved by arranging the CF nanodots.

Ferroelectric properties and piezoresponse force micoroscopy study of Bi3TaTiO9 thin films.

We investigate the ferroelectric properties and crystal structures of Bi3TaTiO9 (BTTO) thin films deposited on single-crystal Nb-doped (100) SrTiO3 substrates via pulsed laser deposition. The BTTO films exhibited either a (001)-epitaxial crystalline structure or a mixed a- and c-oriented polycrystalline structure depending on the substrate temperature. The ferroelectric polarization and piezoelectric coefficient of the mixed a- and c-oriented film were larger than those of the (001)-epitaxial film because its polar axis was perpendicular to the c-axis. Vertical and lateral piezoresponse force microscopy studies indicate that the ferroelectric domains of the (001)-epitaxial film were all parallel to the in-plane orientation, whereas the mixed a- and c-oriented film comprised both square grains with in-plane-oriented ferroelectric domains and longish grains with ferroelectric domains out of orientation with the plane.

Effects of a Nb nanopin electrode on the resistive random-access memory switching characteristics of NiO thin films.

We report the effects of bottom electrode shapes on resistive random-access memory (RRAM) devices composed of Nb (bottom electrode)/NiO (dielectric)/Nb (top electrode) structures. By adopting a nano-fabrication process using an anodic aluminum oxide (AAO) nanotemplate, a well-aligned Nb nanopin array bottom electrode was formed on the surface of a Si substrate. For comparison, a Nb thin film was employed as a different type of bottom electrode. Then, a NiO thin film dielectric was prepared on both the Nb bottom electrodes via a spin coating method, followed by Nb sputtering for the Nb top electrode. Both the RRAM devices with Nb nanopin and thin film bottom electrodes exhibited typical unipolar resistive switching behavior. However, a lower SET/RESET voltage was observed for the Nb nanopin electrode compared to the Nb thin film electrode by virtue of an enhanced electric field induced by the nanopin-shaped electrode. More significantly, on the basis of endurance and retention characteristics, the Nb nanopin electrode played a key role in minimizing the dispersion of the low- and high-resistance state currents and the variation in the SET/RESET voltage by developing more-concise conducting filaments in the conducting path. Therefore, we foresee that this approach can provide an insight into the optimal design of RRAM devices.

Short-wavelength infrared photodetector on Si employing strain-induced growth of very tall InAs nanowire arrays.

One-dimensional crystal growth enables the epitaxial integration of III-V compound semiconductors onto a silicon (Si) substrate despite significant lattice mismatch. Here, we report a short-wavelength infrared (SWIR, 1.4-3 µm) photodetector that employs InAs nanowires (NWs) grown on Si. The wafer-scale epitaxial InAs NWs form on the Si substrate without a metal catalyst or pattern assistance; thus, the growth is free of metal-atom-induced contaminations, and is also cost-effective. InAs NW arrays with an average height of 50 µm provide excellent anti-reflective and light trapping properties over a wide wavelength range. The photodetector exhibits a peak detectivity of 1.9 × 10(8) cm · Hz(1/2)/W for the SWIR band at 77 K and operates at temperatures as high as 220 K. The SWIR photodetector on the Si platform demonstrated in this study is promising for future low-cost optical sensors and Si photonics.

Structural and optical properties of the In(x)Ga(1-x)As nanowires grown on SiO2 via vapor-liquid-solid method.

We report the crystal growth of the In(x)Ga(1-x)As nanowires (NWs) on SiO2 substrate using metal organic chemical vapor deposition. Au nanoparticles which are disintegrated from thin Au film have been used as a catalyst for the vapor-liquid-solid growth. Electron microscopy characterization is performed to investigate the structural properties of the In(x)Ga(1-x)As NW. The In(x)Ga(1-x)As NW grown under an optimal condition has a single-crystal wurtzite structure without any misfit dislocation or stacking fault. Strong room temperature photoluminescence peaks are observed from In(x)Ga(1-x)As NWs passivated by GaAs. Very low light reflectance is measured at the NW surface in the wavelength range from 250 to 1200 nm. The single crystal In(x)Ga(1-x)As NWs are applicable to the various electrical and optical devices.

Can we predict postoperative pancreatic leakage after pancreaticoduodenectomy using preoperative fecal elastase-1 level?

INTRODUCTION: The measurement of fecal elastas-1 in stools is a sensitive and relatively inexpensive noninvasive test. The aim of this study was to study fecal elastase levels in patients who develop pancreatic leakage after pancreaticoduodenectomy (PD) to determine if fecal elastase level can be used to predict patients at high risk for pancreatic leakage after PD. METHODS: Pancreatic function was considered normal when fecal elastase-1 concentration exceeded 200 µg/g feces and moderately or severely insufficient when fecal elastas-1 concentration was less than 200 µg/g feces. RESULTS: Of 123 patients who underwent PD, 67 (54.5%) showed fecal elastase-1 levels less than 200 µg/g, indicating moderate or severe pancreatic insufficiency. Pancreas texture, pathology origin, and level of γ-glutamyl transferase (r-GT) were significantly correlated with fecal elastas-1 level. On univariate analysis, the incidence of pancreatic leakage was significantly greater in the group with normal fecal elastase-1 level (≥200 µg/g), pathologic origin (bile duct/ampulla/duodenum), and soft pancreas texture. In multivariate analysis, normal fecal elastase-1 level (≥200 µg/g) and soft pancreatic texture were identified as independent factors for pancreatic leakage. CONCLUSIONS: Fecal elastase-1 is the most simple and objective method for predicting pancreatic leakage after PD.

Drainage volume after pancreaticoduodenectomy is a warning sign of chyle leakage that inversely correlates with a diagnosis of pancreatic fistula.

BACKGROUND: Chyle leakage is a rare complication of pancreaticoduodenectomy (PD), and its association with pancreatic fistula has not been established. The aim of this study was to (1) evaluate the incidence, management, and risk factors of chyle leakage after PD; (2) determine if there is a relation between chyle leakage and diagnosis of pancreatic fistula; and (3) predict chyle leakage with drainage volume early. METHODS: A total of 222 patients underwent PD or pylorus-preserving PD. We used the clinical database registry system of the Gangnam Severance Hospital, Yonsei University Health System to establish a retrospective cohort with clinicopathologic data. RESULTS: Altogether, 24 patients (10.8 %) developed chyle leakage. Chyle leakage was identified at a median 5 days after surgery and a mean 2 days after enteral intake. The mean drain triglyceride level was 315 mg/dl. Early enteral intake was independently associated with chyle leakage. Chyle leakage was inversely correlated with a diagnosis of pancreatic fistula with marginal significance (odds ratio 0.27; 95 % confidence interval 0.66-1.09). The receiver operating characteristic curve of the volume on postoperative day 4 demonstrated an area under the curve of 0.740 (p = 0.0001). Drainage >335 ml indicated possible chyle leakage. CONCLUSIONS: Chyle leakage after PD is associated with early enteral intake. It was inversely correlated with a diagnosis of pancreatic fistula because of the dilution effect of drainage volume on the concentration of drained amylase. Because early diagnosis helps with appropriate management, prediction/suspicion of chyle leakage based on drainage volume may be useful.