Prognostic roles of leptin-signaling proteins, PD-L1, and tumor-infiltrating lymphocytes in surgically-resected biliary tract cancers.

BACKGROUND: Biliary tract cancers are rare, with a poor patient prognosis. Leptin and programmed death-ligand 1 (PD-L1) influence CD8+ and forkhead box P3 (FOXP3)+ lymphocytes, and thus, cancer cell growth. We aimed to define the prognostic implications of these variables and the clinicopathological features of biliary tract cancers. METHODS: Immunohistochemistry for leptin signaling-related proteins (leptin, leptin receptor, pSTAT3, extracellular-regulated kinase, mammalian target of rapamycin), PD-L1, CD8, and FOXP3 and in situ hybridization for Epstein-Barr virus-encoded small RNAs were performed in 147 cases of surgically-resected biliary tract cancers. RESULTS: Immune cell PD-L1-positivity, tumor size < 3 cm, adjuvant chemotherapy, no recurrence, and early-stage tumors were correlated with better 5-year survival in the tumoral PD-L1(-) and leptin(-) subgroups, and extrahepatic cholangiocarcinoma through multivariate analysis (all p < 0.05). Immune cell PD-L1 and adjuvant chemotherapy lost its prognostic significance in the tumoral PD-L1+ and leptin+ subgroups. CONCLUSIONS: The prognostic implication of the variables may depend upon tumoral protein expression and the anatomical site. Immune cell PD-L1-positivity and the administration of adjuvant chemotherapy may indicate the favorable survival of patients with surgically-resected biliary tract cancers, specifically, in the tumoral PD-L1(-) or tumor leptin(-) subgroups and extrahepatic cholangiocarcinoma. PD-L1- or leptin-targeted therapy combined with conventional chemotherapy may benefit the tumoral PD-L1+ or leptin+ subgroups.

The herbal formula KH-204 is protective against erectile dysfunction by minimizing oxidative stress and improving lipid profiles in a rat model of erectile dysfunction induced by hypercholesterolaemia.

BACKGROUND: Hypercholesterolaemia (HC) is a major risk factor for ischemic heart disease and is also known to be a risk factor for erectile dysfunction (ED). ED caused by HC is thought to be related to HC-induced oxidative stress damage in the vascular endothelium and erectile tissue. KH-204 is an herbal formula with a strong antioxidant effect. We evaluated the effects of KH-204 on erectile function in a rat model of HC-induced ED. METHODS: Male Sprague-Dawley rats (6 weeks old) were divided into normal control, high-fat and cholesterol diet (HFC), and HFC with KH-204 treatment (HFC + KH) groups (n = 12 each). Normal control group rats were fed normal chow diet. HFC and HFC + KH group rats were fed high-fat and cholesterol diets and treated with or without daily oral doses of KH-204 for 12 weeks. Subsequently, intracavernous pressure (ICP) and mean arterial pressure (MAP) were measured, and lipid profiles, expression of endothelial (eNOS) and neuronal (nNOS) nitric oxide synthase, oxidative stress (8-hydroxy-2-deoxyguanosine), and ratio of smooth muscle cells and collagen fibres were evaluated in the serum and corpora tissue. RESULTS: Compared to the HFC group, the HFC + KH group showed statistically significant increases in peak ICP and ICP/MAP ratio, expression of eNOS and nNOS, and ratio of smooth muscle cells and collagen fibres (p < 0.05). The HFC + KH group also showed statistically significant decreases in oxidative stress (p < 0.05). Further the lipid profiles of this group were ameliorated compared to those of the HFC group (p < 0.05). CONCLUSIONS: The current study shows that the antioxidant and hypolipidemic effects of KH-204 are effective in ameliorating ED by restoring endothelial dysfunction and suggests that KH-204 may be a potential therapeutic agent for ED by correcting the fundamental cause of ED.

Comparison of Surgical Outcomes of Robot-Assisted and Laparoscopy-Assisted Pylorus-Preserving Gastrectomy for Gastric Cancer: A Propensity Score Matching Analysis.

BACKGROUND: The three-dimensional view and articulating devices in robot system might have a benefit performing the delicate procedure of pylorus-preserving gastrectomy. This study was conducted to evaluate the feasibility and safety of robot-assisted pylorus-preserving gastrectomy (RAPPG) and to compare the perioperative outcomes and oncologic safety between RAPPG and laparoscopy-assisted pylorus-preserving gastrectomy (LAPPG) for middle-third early gastric cancer. METHODS: Between June 2008 and December 2013, we retrospectively collected data of 68 patients with RAPPG and propensity score matched 68 patients with LAPPG for the treatment of early gastric cancer at Seoul National University Hospital. The covariates for propensity score matching were: age, sex, American Society of Anesthesiologists score, body mass index, and operators. Clinicopathologic characteristics and surgical outcomes were compared between the two groups. RESULTS: All RAPPG cases were performed successfully without open or laparoscopic conversion. Patient demographics and perioperative outcomes did not differ between the two groups except in operation time (258.3 vs. 193.9 min; P < 0.001). There was no significant difference in complication rates between the two groups (19.1 vs. 22.1 %; P = 0.671). The mean number of examined lymph nodes (33.4 vs. 36.5; P = 0.153), and the mean number of lymph nodes at each station was not different between the two groups. CONCLUSIONS: RAPPG can be a safe treatment option for middle-third early gastric cancer in terms of surgical complications and oncologic outcomes. However, RAPPG has no benefit over LAPPG in this study.

A new surgical technique for concealed penis using an advanced musculocutaneous scrotal flap.

BACKGROUND: Until recently, no single, universally accepted surgical method has existed for all types of concealed penis repairs. We describe a new surgical technique for repairing concealed penis by using an advanced musculocutaneous scrotal flap. METHODS: From January 2010 to June 2014, we evaluated 12 patients (12-40 years old) with concealed penises who were surgically treated with an advanced musculocutaneous scrotal flap technique after degloving through a ventral approach. All the patients were scheduled for regular follow-up at 6, 12, and 24 weeks postoperatively. The satisfaction grade for penile size, morphology, and voiding status were evaluated using a questionnaire preoperatively and at all of the follow-ups. Information regarding complications was obtained during the postoperative hospital stay and at all follow-ups. RESULTS: The patients' satisfaction grades, which included the penile size, morphology, and voiding status, improved postoperatively compared to those preoperatively. All patients had penile lymphedema postoperatively; however, this disappeared within 6 weeks. There were no complications such as skin necrosis and contracture, voiding difficulty, or erectile dysfunction. CONCLUSIONS: Our advanced musculocutaneous scrotal flap technique for concealed penis repair is technically easy and safe. In addition, it provides a good cosmetic appearance, functional outcomes and excellent postoperative satisfaction grades. Lastly, it seems applicable in any type of concealed penis, including cases in which the ventral skin defect is difficult to cover.

Primary mucinous cystadenocarcinoma of the renal pelvis misdiagnosed as ureteropelvic junction stenosis with renal pelvis stone: a case report and literature review.

BACKGROUND: Primary mucinous adenocarcinoma of the renal pelvis is extremely rare, with only ~100 cases reported till now. Its presumed pathogenesis includes glandular metaplasia of the urothelium of the calyces and the pelvis and malignant transformation of the metaplasia. Unfortunately, it has no characteristic symptoms or radiological features. We report a case of primary mucinous adenocarcinoma of the renal pelvis misdiagnosed as ureteropelvic junction stenosis with a renal pelvis stone. CASE PRESENTATION: A 50-year-old man presented with discomfort in his right flank after a fall. A physical examination was normal except mild costovertebral angle tenderness on the right side. The results of most laboratory tests were within normal limits. Plain radiography of the kidneys, ureter, and urinary bladder showed a large radio-opaque mass in the right kidney. Abdominal computed tomography showed a hyperdense mass with 2.62 × 5.70 cm size in the right renal pelvis and severe hydronephrosis and cortical thinning. Diuretic-enhanced 99mTc DTPA renal scanning showed that the relative function of the right versus the left kidney was 20 versus 80 %. On the basis of the imaging findings, kidney dysfunction due to ureteropelvic junction stenosis with a large stone was initially diagnosed. However, the drained urine volume was almost zero, and gelatinous material was aspirated when percutaneous nephrostomy was performed for decompression of hydronephrosis. Although the cytopathology of gelatinous material was negative for malignancy, we could not rule out other disease, such as hidden malignancies of the kidney. We therefore performed radical nephrectomy, and pathological examination of the kidney uncovered a mucinous cystadenocarcinoma in the renal pelvis. A bone scan and positron emission tomography showed no evidence of other malignancies, metastasis, or remnant cancer. The patient has been well, without evidence of tumour recurrence or metastasis, for 20 months after surgery. CONCLUSIONS: Primary mucinous adenocarcinomas of the renal pelvis are extremely rare, and most are diagnosed via post-operative analysis of resected specimens. Although preoperative diagnosis is difficult, urologists should consider the possibility of primary mucinous adenocarcinoma in patients with severe hydronephrosis accompanied by renal stones and chronic inflammation.

Laparoscopy-assisted pylorus-preserving gastrectomy is better than laparoscopy-assisted distal gastrectomy for middle-third early gastric cancer.

OBJECTIVE: The purpose of this study is to compare the surgical, oncologic safety and the nutritional, functional benefit of laparoscopy-assisted pylorus-preserving gastrectomy (LAPPG) with laparoscopy-assisted distal gastrectomy (LADG) for middle-third early gastric cancers (EGC). BACKGROUND: Of those patients with middle-third EGC, it is still difficult to determine which procedure is better between LADG and LAPPG despite alleged advantages of LAPPG. METHODS: For middle-third EGC, a retrospective analysis was performed comparing those who underwent LADG and those who underwent LAPPG. To evaluate surgical and oncologic safety, clinicopathologic differences including the postoperative morbidity, the pattern of lymph node metastasis and recurrence were analyzed. Postoperative protein, albumin, quantification of abdominal fat area using abdomen computed tomography, and the incidence of postoperative gallstone were compared for the evaluation of functional advantages. RESULTS: The overall postoperative morbidity rate was similar between LADG (n = 176) and LAPPG (n = 116). Delayed gastric emptying was less frequent in LADG than in LAPPG (1.7% vs 7.8%); however, the rates of all the other complications were significantly higher in LADG than in LAPPG (17.0% vs 7.8%). The number of examined lymph nodes and metastatic lymph nodes at each lymph node station was not significantly different and 3-year recurrence-free survival rates were also similar between LADG and LAPPG (98.8% vs 98.2%). Decreases in serum protein and albumin in postoperative 1 to 6 months and abdominal fat area in postoperative 1 year were significantly greater in LADG than in LAPPG. The 3-year cumulative incidence of gallstone was significantly higher in LADG than in LAPPG (6.5% vs 0.0%). CONCLUSIONS: For middle-third EGC, LAPPG can be considered as a better treatment option than LADG in terms of nutritional advantage and lower incidence of gallstone.

Effector Function Characteristics of Exhausted CD8+ T-cell in Microsatellite Stable and Unstable Gastric Cancer.

Purpose: Gastric cancer exhibits molecular heterogeneity, with the microsatellite instability high (MSI-H) subtype drawing attention for its distinct features. Despite a higher survival rate, MSI-H gastric cancer lack significant benefits from conventional chemotherapy. The immune checkpoint inhibitors (ICIs), presents a potential avenue, but a deeper understanding of the tumor immune microenvironment of MSI-H gastric cancer is essential. Materials and Methods: We explored the molecular characteristics of CD8+ T cell subtypes in three MSI-H and three microsatellite stable (MSS) gastric cancer samples using single-cell RNA sequencing and spatial transcriptome analysis. Results: In MSI-H gastric cancer, significantly higher proportions of effector memory T cell (Tem), exhausted T cell (Tex), proliferative exhausted T cell (pTex), and proliferative T cell were observed, while MSS gastric cancer exhibited significantly higher proportions of mucosal-associated invariant T (MAIT) cell and NKT cell. In MSI-H gastric cancer, Tex and pTex exhibited a significant upregulation of the exhaustion marker LAG3, as well as elevated expression of effector function markers such as IFNG, GZMB, GZMH, and GZMK, compared to those in MSS gastric cancer. The IFN-γ signaling pathway of Tex and pTex was retained compared to those of MSS gastric cancer. The spatial transcriptome analysis demonstrates the IFN-γ signaling pathway between neighboring Tex and malignant cell, showcasing a significantly elevated interaction in MSI-H gastric cancer. Conclusion: Our study reveals novel finding indicating that IFN-γ signaling pathway is retained in Tex and pTex of MSI-H gastric cancer, offering a comprehensive perspective for future investigations into immunotherapy for gastric cancer.

Outcomes of surgery aiming at curative resection in good responder to induction chemotherapy for gastric cancer with distant metastases.

BACKGROUND: The aim of this study is to analyze the outcome of surgery with curative intent in good responder to induction chemotherapy for gastric cancer with distant metastases (M1 gastric cancer). MATERIALS AND METHODS: We reviewed M1 gastric cancer patients in whom radiologic evaluation suggests disappearance of metastatic lesion after chemotherapy and received operation from January 2000 to December 2009. Clinicopathologic variables and oncologic outcomes were evaluated. RESULTS: Of the 34 patients who underwent surgery with curative intent after chemotherapy, overall R0 resection rate was 76.5% (26/34). R0 resection rate was 88.0% (22/25) in initial one metastatic site and 44.4% (4/9) in two metastatic sites (P = 0.017). Postoperative morbidity and mortality rate were 14.7% and 0%. Recurrence rate was 61.5% (16/26) after R0 resection. Median survival was 22.9 and 7.8 months according to R0 versus non-R0 resection (P = 0.033). After R0 resection, 3-year overall survival was 51.7% in ypN0-2 stage group. CONCLUSION: The present study provides evidence that in patients with M1 gastric cancer which confined to one site who respond well to induction chemotherapy, a higher rate of R0 resection and longer survival can be expected. A multicenter cohort study is needed to explore this concept further.

Impact of perioperative hemoglobin levels on postoperative outcomes in gastric cancer surgery.

BACKGROUND: The aim of this study was to evaluate the association of postoperative blood transfusion and anemia with postoperative outcomes in gastric cancer surgery. METHODS: We enrolled 588 patients who had undergone curative resection for gastric cancer. Input variables for risk assessment consisted of 3 categories: patient demographics, surgical and pathological factors, and anemia-related factors. Postoperative outcomes included 30-day morbidity and mortality. Univariate and multivariate analyses were performed to identify risk factors influencing postoperative complications. RESULTS: The rate of total complications was 19.0%. Comorbidity, lowest hemoglobin (Hb) level from the operative day up to postoperative day 7 (LOW-Hb), the percentage of drop in Hb level on postoperative day 2 (POD2-Hb change), and postoperative transfusion were independent risk factors in the multivariate analysis, with LOW-Hb and postoperative transfusion found to be the most significant factors. When LOW-Hb was ≥9.0 g/dL, postoperative complications were higher in the transfused group than in the non-transfused group (60.0 vs. 14.2%, respectively, p = 0.024), but when LOW-Hb was <9.0 g/dL, postoperative complications were not different between the 2 groups (44.6 vs. 37.5%, p = 0.525). CONCLUSION: The lowest postoperative Hb level and postoperative transfusion were the most significant risk factors for postoperative complications in gastric cancer surgery.

Changes of neuregulin-1 (NRG-1) expression in a rat model of overactive bladder induced by partial urethral obstruction: is NRG-1 a new biomarker of overactive bladder?

BACKGROUND: To determine whether neuregulin-1(NRG-1) is a potential new biomarker of overactive bladder (OAB) induced by partial urethral obstruction in a rat model of OAB and to evaluate the urothelium as a therapeutic target of OAB. METHODS: Female Sprague-Dawley rats were separated into three 20-animal groups: normal, OAB, and 5-hydroxymethyl tolterodine (5-HMT)-treated OAB. In the OAB and OAB + 5-HMT groups, the urethra of each animal was partially obstructed; the OAB + 5-HMT group received intravenous 5-HMT for 3 weeks. At the conclusion of the 5-HMT dosing, the rats in each group underwent cystometrography, and the bladders were histologically evaluated. The expression of brain derived-neurotrophic factor (BDNF) and NRG-1 were evaluated in the urothelium. RESULTS: Compared with the control group, the OAB group showed a markedly increased bladder weight and a significant decrease in the micturition interval and volume; rats in the OAB + 5-HMT group showed decreased bladder weights and an improved micturition interval and volume. BDNF and NRG-1 were expressed at significantly higher levels in the OAB group, and were significantly reduced in the OAB + 5-HMT group compared with the control group. CONCLUSIONS: The study suggests that NRG-1 is a potential new biomarker of OAB; the urothelium might be a therapeutic target for OAB treatment.

A rare case of primary malignant small cell carcinoma combined with urothelial cell carcinoma in the ureter.

BACKGROUND: Extrapulmonary small cell carcinomas have been reported in a variety of organs, and their incidence in the genitourinary tract is second only to that in the gastrointestinal tract. To date, however, only a few cases of small cell carcinoma of the ureter have been reported. Because the extreme rarity of this type of carcinoma, its clinical behaviour, diagnostic methods, and effective treatment modalities have not yet been determined. CASE PRESENTATION: A 59-year-old man presented with a 1-month history of painless gross haematuria. Urine cytopathology revealed a urothelial carcinoma and computed tomography revealed left hydronephroureterosis with a distal ureteral stone and a mildly enhanced fungating mass just below the stone-impacted site. The preoperative TNM stage was T2N0M0. The patient underwent simultaneous diagnostic ureterorenoscopy and left laparoscopic nephroureterectomy with bladder cuff resection. Gross examination showed a 3.5 × 3.0 × 0.8 cm white, partly yellow mass in the left distal ureter. Light microscopy showed a small cell carcinoma, overlaid on a urothelial carcinoma in situ, invading the ureter and external lateral resection margins. The small cell carcinoma was diffusely positive for neuron-specific enolase, and exhibited focal positivity for CD 56, synaptophysin, chromogranin and cytokeratin 20. The patient was treated with adjuvant chemotherapy, consisting of cisplatin and etoposide, and radiation therapy, and has been well, without evidence of tumour recurrence or metastasis in the 10 months after surgery. CONCLUSION: Small cell carcinoma of the ureter is rare. Although its clinical behaviour and diagnostic modalities have not been determined and it has yet to be diagnosed immunohistopathologically, multimodality treatment including surgery, chemotherapy and radiotherapy may improve patient survival.

Should adenocarcinoma of the esophagogastric junction be classified as esophageal cancer? A comparative analysis according to the seventh AJCC TNM classification.

OBJECTIVE: The aim of this study was to evaluate the adequacy of esophageal classification for adenocarcinoma of the esophagogastric junction (AEJ) of the seventh American Joint Committee on Cancer (AJCC) TNM classification. BACKGROUND: The seventh AJCC TNM classification proposed the new classification for AEJ as a part of esophageal cancer depending on the esophagogastric junction (EGJ) involvement. However, there are still many controversies over the classification system for AEJ. METHODS: A review of pathologic reports and photographic findings at Seoul National University Hospital from 2003 to 2009 identified 4524 patients with single, primary adenocarcinoma of the EGJ (n = 497) and other regions of the stomach (GC, n = 4027) who underwent an operation with curative intent. We analyzed the clinicopathologic features and postoperative prognosis of AEJ using the Siewert classification and the seventh AJCC TNM classification. RESULTS: There was no Siewert type I (AEJ I) in this study. The prognosis of AEJ was similar to that of GC. There was no difference in clinicopathologic features between AEJ II and AEJ III. Even though AEJ extending into the EGJ (AEJe) showed more advanced pathologic features than AEJ not extending into the EGJ (AEJg), the prognosis of AEJe and AEJg was not significantly different when stratified by T stage. Compared with the classification of gastric cancer applied for AEJ, esophageal classification for AEJ from the seventh AJCC TNM classification showed a loss of distinctiveness at each TNM stage. CONCLUSIONS: To evaluate the postoperative prognosis of AEJ within the stomach, AEJ II and AEJ III should be considered a part of gastric cancer irrespective of EGJ involvement.

The value of palliative gastrectomy in gastric cancer with distant metastasis.

PURPOSE: The purpose of this study was to examine the value of surgical resection and to find prognostic factors for metastatic gastric cancer. METHODS: Clinicopathological data of 257 cM1 gastric cancer patients who underwent an operation at Seoul National University Hospital from January 1999 to December 2004 were reviewed. Patients were grouped into the resection (RS, n=165) and nonresection groups (NR, n=92). To evaluate whether there was any selection bias, patients were stratified according to chemotherapy and preoperative CT findings were compared. RESULTS: There were no significant differences in clinicopathologic features and preoperative CT findings between the RS and NR groups. For chemotherapy, the RS group had a survival benefit (median survival; 12.7 vs. 11.2 months, p=0.0107). In the subanalysis, there was a survival benefit to the RS group when metastasis was confined to one site (14 vs. 9.7 months, p=0.04). In patients with no chemotherapy, the RS group had no benefit (p=0.151). In univariate and multivariate analyses, resection (p=0.001), chemotherapy (p<0.001), the number of organs with metastatic lesions (p=0.003), and elective operation (p<0.001) were significant prognostic factors. CONCLUSIONS: This retrospective study suggests that surgical resection in metastatic gastric cancer may improve survival when combined with chemotherapy, especially when metastasis is confined to one site.

Effects of anthocyanin extracted from black soybean seed coat on spermatogenesis in a rat varicocele-induced model.

Varicocele is the most common cause of primary male infertility and is associated with oxidative stress. The aim of the present study was to investigate the effects of anthocyanin on a rat model of varicocele. Twenty-four male rats were divided into four experimental groups: a normal control group, a varicocele-induced control group and two varicocele-induced groups treated with either 40 or 80mgkg(-1), p.o., anthocyanin for 4 weeks. Varicocele was induced by the partial obstruction of the left renal vein. After 8 weeks, the testes and epididymides from rats in all groups were removed, weighed and subjected to histological examination and semen analysis. Apoptosis in the testes was determined by terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL) and oxidative stress was assessed by measuring 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels. Although no significant differences in sperm counts were observed among the groups, anthocyanin treatment of the varicocele-induced groups resulted in significantly increased testes weight, sperm motility and spermatogenic cell density (P<0.05). Anthocyanin treatment also significantly decreased apoptotic body count and 8-OHdG concentrations (P<0.05). We suggest that the antioxidant effect of anthocyanin prevented the damage caused by varicocele-induced reactive oxygen species.

Acute bacterial prostatitis: how to prevent and manage chronic infection?

We conducted a retrospective analysis of acute bacterial prostatitis (ABP) to evaluate the factors of progressing to chronic infection and chronic pelvic pain syndrome IIIa (CPPS IIIa) from ABP. The clinical records of 480 cases compatible with a confirmed diagnosis of ABP from five urological centers between 2001 and 2010 were reviewed. We defined chronic infection (CI) as a progression to chronic bacterial prostatitis (II), epididymo-orchitis, and showing persistent pyuria and bacteriuria after treatment of ABP in admission periods when followed up at 3 months or more. Results were analyzed according to two categories: category I, developed to CI (group A, n = 49) versus recovered without CI or CPPS IIIa (group C, n = 385); and category II, developed to CPPS IIIa (group B, n = 46) versus recovered without CI or CPPS IIIa (group C, n = 385). Of the 480 ABP patients, 10.2% (49/480) progressed to CI and 9.6% (46/480) progressed to CPPS IIIa. The frequency of CI was 11.3% (49/434) and that of CPPS IIIa was 10.7% (46/431). The factors that affected progression to CI were diabetes, prior manipulation, not doing cystostomy, and urethral catheterization (P < 0.05). The factors that affected progression to CPPS IIIa were the same as CI, but prostate volume was included in the CPPS IIIa group (P < 0.05). The identification and characterization of these factors may accelerate the development of preventive, diagnostic, and therapeutic strategies for the treatment of CI and CPPS IIIa from ABP.

Adaptive double-sided fluidic lens of polydimethylsiloxane membranes of matching thickness.

A fluidic lens with double-sided polydimethylsiloxane membranes of different thicknesses that complement each other to reduce spherical aberration was fabricated. It is operated with magnetic repulsion induced by the current in the voice coil. The optical power of the proposed lens was observed to be considerably higher compared to that of a typical convex glass lens. The focal lengths of rays passing through the optical axis and the edge of the lens was measured and compared with the simulation data. The spherical aberration of the proposed lens was observed to be negligibly small compared to that of a plano-convex lens.

Nonvolatile-memory characteristics of SiC nanocrystals with variable oxide thickness and crested tunnel barriers.

The electrical characteristics of SiC nanocrystal nonvolatile-memory devices with variable oxide and crested tunnel barriers consisting of a SiO2/Si3N4/SiO2 (ONO) and a Si3N4/SiO2/Si3N4 (NON) layer, respectively, were investigated. The equivalent oxide thickness of the ONO and NON tunnel barriers were about 5.6 nm and 5.2 nm, respectively. When the +/- 13 V bias voltage was applied for 500 ms, the threshold voltage shifts of the SiC-nanocrystal-embedded memory devices with ONO and NON tunnel barriers were about 2.4 V. The operation speeds of the memories with ONO and NON tunnel barriers under the +/- 10 V applied pulse bias were approximately 5 and 20 ms, respectively. The field sensitivity of the ONO tunnel barrier was higher than that of the NON tunnel barrier during electron injection. The tunneling efficiency during the programming/erasing processes could be improved by the engineered tunnel barrier layer. Therefore, the SiC-nanocrystal-embedded memory device with an ONO tunnel barrier can be applied to nonvolatile-memory devices.

Thermal stability of metal-silicide nanocrystal nonvolatile memory with barrier engineered tunnel layers.

WSi2 nanocrystal nonvolatile memory devices were fabricated with a silicon oxide-nitride-oxide (SiO2: 2 nm/Si3N4:2 nm/SiO2:3 nm) tunnel layer. WSi2 nanocrystals of 2.5 nm diameters and a density of 3.6 x 10(12) cm(-2) were formed using radio frequency magnetron sputtering and annealing processes. The WSi2 nanocrystal nonvolatile memory device exhibited strong thermal stability during writing/erasing operations at temperatures up to 125 degrees C. When the writing/erasing voltages were applied at +10 V/-10 V for 500 ms, the memory window of the initial approximately 2.6 V decreased by approximately 1.1 V at 25 degrees C and 0.4 V at 125 degrees C after 10(4) sec, respectively. These results show that WSi2 nanocrystals with barrier-engineered tunnel layers are possible for application in nonvolatile memory devices.

In2O3 nanocrystal memory with the barrier engineered tunnel layer.

In2O3 nanocrystal memories with barrier-engineered tunnel layers were fabricated on a p-type Si substrate. The structure and thickness of the barrier-engineered tunnel layers were SiO2/Si3N4/SiO2 (ONO) and 2/2/3 nm, respectively. The equivalent oxide thickness of the ONO tunnel layers was 5.64 nm. The average size and density of the In2O3 nanocrystals after the reaction between BPDA-PDA polyimide and the In thin film were about 8 nm and 4 x 10(11) cm(-2), respectively. The electrons were charged from the channel of the memory device to the quantum well of the In2O3 nanocrystal through the ONO tunnel layer via Fowler-Nordheim tunneling. The memory window was about 1.4 V when the program and erase conditions of the In2O3 nanocrystal memory device were 12 V for 1 s and -15 V for 200 ms.

Laparoscopy-assisted distal gastrectomy compared to open distal gastrectomy in early gastric cancer.

BACKGROUND: This study aimed to evaluate the feasibility of laparoscopy-assisted distal gastrectomy (LADG) in early gastric cancer (EGC) with special interest in a learning curve effect. METHODS: The clinical outcomes of EGC patients who underwent LADG (n = 100) and sex-, age- and body mass index- (BMI) matched EGC patients who underwent open distal gastrectomy (ODG; n = 100) were compared retrospectively. In addition, the outcomes between the early (n = 50) and late LADG group (n = 50) were compared. RESULTS: The mean number of retrieved lymph nodes was significantly smaller in the LADG group than in the ODG group (29.3 vs. 36.4, p < 0.001). The operative time of the LADG group was significantly longer than in the ODG group (249.1 vs. 152.9 min, p < 0.001). The complication rates were comparable between both groups (14 vs. 13%, p = 0.84). No cancer-related death was observed in either group. Between early and late LADG groups, the operative time was shorter (p < 0.001) and the number of retrieved lymph nodes was higher (p = 0.016) in the late group. CONCLUSIONS: LADG seems to be a safe and feasible procedure in treating EGC, as it shows comparable outcomes with ODG. The potential disadvantages of LADG, such as longer operation time and smaller number of retrieved lymph nodes, diminished after overcoming the learning curve.