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Background. Nobiletin is a natural compound with anticancer activity; however, the mechanism is not clear. Methods. The inhibitory effect of nobiletin on non-small-cell lung cancer (NSCLC) cells was examined using soft agar, Transwell, and apoptosis analyses. Cancer stemness was measured by sphere assay. Genes and miRNAs regulated by nobiletin were identified by whole-genome sequencing. Protein levels were detected by western blot and immunofluorescence assays. Results. Nobiletin significantly inhibited NSCLC cell colony formation and sphere formation and induced apoptosis. Nobiletin upregulated negative regulators of WNT/β-catenin signaling, including NKD1, AXIN2, and WIF1, while it inhibited the expression of β-catenin and its downstream genes, including c-Myc, c-Jun, and cyclin D1. Furthermore, we identified that GN inhibits miR-15-5p expression in NSCLC cells and that NKD1, AXIN2, and WIF1 are the target genes of miR-15-5p. Conclusions. Nobiletin has a strong inhibitory effect on NSCLC, and nobiletin plays an anticancer role by inhibiting miR-15-5p/β-catenin signaling in NSCLC.

The purpose of this retrospective study was to compare the anastomotic complications after radical total gastrectomy using circular and linear stapler. A total of 121 consecutive patients who had undergone radical total gastrectomy at our hospital between 2010 and 2020 were enrolled. Postoperative complications were analyzed according to the baseline characteristics, surgical method, and type of anastomosis. The incidence of anastomotic stricture was significantly higher in the circular stapler group. Multivariate analyses showed that only the type of stapler used was significantly associated with anastomotic complications (odds ratio [OR] 0.11; 95% confidence interval [CI] 0.012–0.986; P = 0.049). The incidence of anastomotic complications, particularly stenosis, is reduced using a linear stapler. Therefore, such as stapler is more suitable for anastomosis after total gastrectomy during both laparoscopic and open surgeries.

Background: Hybrid appendectomy (HA) has the technical advantages of the excellent visual field provided by laparoscopic surgery and is fast and easy similar to open surgery. We aimed to compare th...

With continued technical advances in surgical instruments and growing expertise, several surgeons have performed laparoscopic pylorus preserving pancreaticoduodenectomy (L-PPPD) safely with good results, and the laparoscopic approach is being performed more frequently. We performed over 100 cases of L-PPPD and compared their outcomes to those of open PPPD (O-PPPD) using the large sample size. The aim of the present study was to evaluate the safety and feasibility of L-PPPD compared with O-PPPD. From September 2012 to June 2017, PPPD was performed for 217 patients at Yonsei University Severance Hospital by a single surgeon. Patients were divided into two groups: those who underwent O-PPPD (n = 113) and those who underwent L-PPPD (n = 104). We performed a 1:1 propensity score-matched (PSM) analysis and retrospectively analyzed the demographic and surgical outcomes. We also reviewed all previous studies of more than 100 cases. The L-PPPD group had lesser intraoperative blood loss than the O-PPPD group (548.1 ml vs. 244.7 ml; p

Purpose Recent studies have analyzed the short-term clinical outcomes of ndovascular management. However, the long-term outcomes are unknown. This study aimed to investigate clinical outcomes after endovascular management for ruptured pseudoaneurysm in patients after pancreaticoduodenectomy (PD). Methods The medical records of 2,783 patients who underwent PD were retrospectively reviewed at a single center. Of 62 patients who received intervention after pseudonaeurysm rupture, 57 patients (91.9%) experienced eventual success of hemostasis. The patients were composed as follows: (embolization only [EMB], n = 30), (stent-graft placement only [STENT], n = 19) and (both embolization and stent-graft placement simultaneously or different times [EMB + STENT], n = 8). Long-term complications were defined as events that occur more than 30 days after the last successful endovascular treatment. Results Among 57 patients, short-term stent-graft related complications developed in 3 patients (5.3%) and clinical complication developed in 18 patients (31.5%). Nine (15.8%) had long-term stent-graft related complications, which involved partial thrombosis in 5 cases, occlusion in 3 cases and migration in 1 case. Except for 1 death, the remaining 8 cases did not experience clinical complications. The stent graft primary patency rate was 88.9% after 1 month, 84.2% after 1 year, and 63.2% after 2 years. Of 57 patients, 30 days mortality occurred in 8 patients (14.0%). Conclusion After recovery from initial complication, most of patients did not experience fatal clinical complication during long-term follow-up. Endovascular management is an effective and safe management of pseudoaneurysm rupture after PD in terms of long-term safety.

Background To compare the number of lymph nodes (LNs) detected when using Carnoy's solution (CS) versus 10% neutral buffered formalin (NBF) to fix specimens after radical gastrectomy for gastric cancer. Patients and methods LNs were routinely detected using NBF until 2020, since then, for the fixation procedure, residual fat was fixed in CS for 24 hours and dissected again for the detection of further LNs. Of 143 specimens, 117 were included in the NBF group and 26 in the CS group. Results The mean numbers of LNs examined were 27.85±14.89 and 36.30±12.41 in the NBF and CS groups, respectively (p=0.008). The mean number of additional LNs detected using CS was 8.07±2.91, of which 0.38±1.02 were metastatic. Additional LNs were found in all patients of the CS group, and all were ≤3 mm. Of the 26 patients in the CS group, metastatic LNs were detected in four, disease in two of whom was up-staged. Conclusion CS is an appropriate alternative to NBF for the fixation of gastric cancer specimens, and more LNs were detected in the resected specimens fixed when using CS compared with NBF.

To compare the effectiveness of a custom-made skills simulator (CMSS) with the commercially available da VinciA randomized control study was conducted to determine the performance of participants after undergoing robotic surgical training. Total 64 students who had no previous experience with robotic surgery enrolled this study. After 5 min-introduction of robotic surgical system, the participants got random-assignment into two groups to perform either CMSS-or DVSS-exercises. After 15 min-practicing the corresponding simulator, task-execution performance and individual questionnaires were compared between participants trained with the CMSS and those trained with the DVSS.Regardless of simulator the participants used, the system understanding and manipulation ability of the participants was found to be higher than after completing the simulation-based robotic surgical training (p 0.05). However, there were no significant differences in terms of the required time to complete the tasks, and improvement of understanding the concept of robotic surgery, or surgical skill capacity between two groups (p 0.05).The training effectiveness of CMSS was not significantly different to DVSS. It can be synergetic tool to DVSS for novice trainees of robotic surgery to get accustomed to the robotic surgical system and to improve their basic robotic surgical skills.

With continued technical advances in surgical instruments and growing expertise, several surgeons have performed laparoscopic pylorus preserving pancreaticoduodenectomy (L-PPPD) safely with good results, and the laparoscopic approach is being performed more frequently. We performed over 100 cases of L-PPPD and compared their outcomes to those of open PPPD (O-PPPD) using the large sample size. The aim of the present study was to evaluate the safety and feasibility of L-PPPD compared with O-PPPD.From September 2012 to June 2017, PPPD was performed for 217 patients at Yonsei University Severance Hospital by a single surgeon. Patients were divided into two groups: those who underwent O-PPPD (n = 113) and those who underwent L-PPPD (n = 104). We performed a 1:1 propensity score-matched (PSM) analysis and retrospectively analyzed the demographic and surgical outcomes. We also reviewed all previous studies of more than 100 cases.The L-PPPD group had lesser intraoperative blood loss than the O-PPPD group (548.1 ml vs. 244.7 ml; p 0.001). Both groups showed similar rates of negative resection margins (99.1% vs. 96.2%; p = 0.196). Overall complication rates did not differ significantly between O-PPPD and L-PPPD (39.8% vs. 35.6%; p = 0.519). The clinically relevant postoperative pancreatic fistula (POPF) rates in the O-PPPD and L-PPPD groups were 18.8% and 13.5%, respectively (p = 0.311). There was no difference in 30- and 90-day mortality rates between the two groups (p = 0.479). Similar results were obtained after PSM analysis.L-PPPD can be a good alternative option for well-selected patients with periampullary lesions requiring PPPD.

Purpose This study compared the patency of the splenic vessels between laparoscopic and open spleen and splenic vessel-preserving distal pancreatectomy. Methods We retrospectively reviewed a database of 137 patients who underwent laparoscopic (n = 91) or open (n = 46) spleen and splenic vessel-preserving distal pancreatectomy at a single institute from 2001 through 2015. Splenic vessel patency was assessed by abdominal computed tomography and classified into three grades according to the degree of stenosis. Results The splenic artery patency rate was similar in both groups (97.8 vs. 95.7%, P = 0.779). Also, the splenic vein patency rate was not significantly different between the 2 groups (74.7% vs. 82.6%, P = 0.521). Postoperative wound complication was significantly lower in the laparoscopic group (19.8% vs. 28.3%, P = 0.006), and hospital stay was significantly shorter in the laparoscopic group (7 days vs. 9 days, P = 0.001) than in the open group. Median follow-up periods were 22 months (3.7-96.2 months) and 31.7 months (4-104 months) in the laparoscopic and open groups, respectively. Conclusion Laparoscopic distal pancreatectomy showed good splenic vessel patency as well as open distal pancreatectomy. For this reason, splenic vessel patency is not an obstacle in performing laparoscopic splenic vessel-preserving distal pancreatectomy.

This paper proposes a 3 kW single-phase bi-directional multi-level converter for energy storage applications. The proposed topology is based on the H-bridge structure with four switches connected to the DC-link. A simple phase opposition disposition PWM method that requires only one carrier signal is also suggested. The switching sequence to balance the capacitor voltage is considered. The topology can be extended to a nine-level converter or a three-phase system. The operating principle of the proposed converter is verified through a simulation and an experiment.

Pancreatic neuroendocrine tumors (PNETs) account for 1–2% of all pancreatic neoplasms. Nonfunctioning PNETs (NF-PNETs) account for 60–90% of all PNETs. Laparoscopic distal pancreatectomy (LDP) is becoming the treatment of choice for benign lesions in the body and tail of the pancreas. However, LDP has not yet been widely accepted as the gold standard for NF-PNETs. The purpose of this study is to evaluate the clinical and oncologic outcomes after laparoscopic versus open distal pancreatectomy (ODP) for NF-PNETs. Between April 1995 and September 2016, 94 patients with NF-PNETs underwent open or laparoscopic distal pancreatectomy at Samsung Medical Center. Patients were divided into two groups: those who underwent LDP and those who underwent ODP. Both groups were compared in terms of clinical and oncologic variables. LDP patients had a significantly shorter hospital stay compared with ODP patients, amounting to a mean difference of 2 days (p

서론 : 현재, 감시림프절 전이가 있는 유방암 환자의 표준 치료는 완전 액와림프절 박리이다. 그러나 유방암 환자의 40~60%는 감시림프절 이외의 나머지 액와림프절에 암 전이를 가지고 있지 않다. 이와 관련하여 많은 연구자들이 감시림프절이 양성인 환자의 비감시림프절 전이 유무를 측정하기 위한 예측 시스템을 개발하였다. 이 연구의 목적은 한림대학교 의과대학 한림성심병원의 환자군에서 각 예측 시스템이 적절히 이용될 수 있는지 알아보고자 하였다. 대상 및 방법 : 2005년부터 2009년까지 감시림프절 생검을 시행한 침습성 유방암 환자 279명을 대상으로 하였다. 단변량 및 다변량 로지스틱 회귀 분석을 이용하여 양성 감시림프절과 감시림프절에 관련된 인자를 정하였으며 감시림프절 전이를 예측하기 위해 MSKCC 노모그램과 비감시림프절과 관련된 5개 예측 모델을 사용하였다. 결과 : 다변량 분석에서 종양의 크기(p=0.004)와 림프혈관 침윤(p 결론 : 모든 예측체계가 본 연구대상 환자들에게 좋은 예측력을 보여주지는 못하여 평가 과정이 없이 예측체계를 사용하는 것은 위험하며 가능하다면 각 기관에 맞는 예측체계를 만드는 것이 좋을 것으로 생각된다.

Purpose: Laparoscopic appendectomy isused as a three port technique for appendectomy. In children, single port laparoscopic appendectomy is difficult because they have a small peritoneal cavity for manipulation of laparoscopic instruments. We performed transumbilical laparoscopic assisted single port appendectomy (hybrid appendectomy) in children. Methods: From March 2010 to July 2012, we performed transumbilical laparoscopic assisted single port appendectomy in 53 children. We made a vertical incision to the umbilicus approximately 1.5 cm, and a wound retractor (Applied Medical Resources Co., Ltd., Rancho Santa Margarita) was placed in the umbilical incision, and appendix exteriorized the extraperitoneum through the wound retractor. Appendectomy was performed conventionally. We had no conversion cases for laparotomy. Results: A total of 53 patients, 29 females and 24 males, with a mean age of 8.5±2.0 years were enrolled in this retrospective study. The mean operative time was 29.4±9.4 minutes. There was no occurrence of complication or mortality. BMI was 17.8±4.9 kg/m². And mean hospital stay was 3.2±1.0 days. Conclusion: In children, transumbilical single port laparoscopic appendectomy is technically difficult because they have a small peritoneal cavity. However, transumbilical laparoscopic assisted single port appendectomy (hybrid appendectomy) appearsto be a safe and effective technique for use in children, which allows for achievement of nearly scarless surgery.

This paper proposes a new dead time compensation method for a PWM inverter. Recently, PWM inverters are extensively used for industry applications, such as ac motor drives, distributed grid-connected systems and a static synchronous compensator (STATCOM). Nonlinear characteristics of the switch and the inverter dead time cause a current distortion and deterioration of power quality. The dominant harmonics in the output current are the and harmonics in the stationary frame, and the harmonics in the synchronous rotating frame. In this paper, a resonant controller which compensates the harmonics in the synchronous rotating frame is proposed. This method does not require any off-line experimental measurements, additional hardware and complicated mathematical computations. Furthermore, the proposed method is easy to implement and does not cause any stability problem.

Purpose Recent studies have suggested microscopic positive resection margin should be revised according to the presence of tumor cells within 1mm of the margin surface in resected specimens of pancreatic cancer. However, the clinical meaning of this revised margin status for R1 resection margin was not fully clarified. Methods From July 2012 to December 2014, the medical records of 194 consecutive patients who underwent pancreaticoduodenectomy for ductal adenocarcinoma of the pancreatic head were analyzed retrospectively. They were divided into 3 groups on margin status; revised microscopic negative margin (rR0) - tumor exists more than 1 mm from surgical margin, revised microscopic positive margin (rR1) - tumor present within less than 1 mm from surgical margin, classic microscopic positive margin (cR1) - tumor is exposed to surgical margin. Results There were 76 rR0 (39.2%), 100 rR1 (51.5%), and 18 cR1 (9.3%). There was significant difference in disease-free survival rates between cR1 vs. rR1 (8.4 months vs. 24.0 months, P = 0.013). Margin status correlated with local recurrence rate (17.1% in rR0, 26.0% in rR1, and 44.4% in cR1, P = 0.048). There is significant difference in recurrence at tumor bed (11.8% in rR0 vs. 23.0 in rR1, P = 0.050). Of rR1, adjuvant treatment was found to be an independent risk factor for local recurrence (hazard ratio, 0.297; 95% confidence interval, 0.127-0.693, P = 0.005). Conclusion Revised R1 resection margin (rR1) affects recurrence at the tumor bed. Adjuvant treatment significantly reduced local recurrence of rR1. Accordingly, adjuvant chemoradiation for rR1 group should be taken into account.

The extra-pulmonary small cell carcinoma is rare disease and most common site is the esophagus. The other sites are stomach, small and large intestine, pancreas, rectum, skin, cervix and larynx, etc. Primary small cell carcinoma of the esophagus is extremely rare with an incidence about 2% of ail esophageal cancer, and about 300 cases reported up till now in the literature. It is an aggressive tumor associated with a poor prognosis due to high rate of early distant metastasis. Almost all esophageal small cell carcinomas occur at the mid or lower esophagus but upper esophagus is rare, encountered for about 3% of all cases. In Korea, 3 cases were reported to locate at the upper esophagus. The optional management has not yet been established, and the role of the surgery has remained controversial. We reported a case of small cell carcinoma of the upper esophagus which underwent esophagectomy with curative intent as part of multimodality treatment.

This paper describes a detailed operation analysis, proposed dc side control strategy, and implementation of the BQ-ZSI (bidirectional quasi-Z-source inverter) for electric vehicle applications. The power flow can be bidirectional by connecting an active switch antiparallel with the diode in BQ-ZSI. The performance of the inverter under load variation can be improved by inserting an inner current control loop of the inductor in the QZSN side controller. Thus, a dedicated voltage controller with inductor current controller is designed to reject the disturbance and stabilize the dc-link voltage during a non-shoot through state. A 5-kW prototype has been built. Both simulation and experimental results are presented to verify the validity of the circuit and the effectiveness of the proposed control strategy.

A novel approach to prepare a polyimide nanofoam was explored by using a polyimide precursor grafted with a labile poly(propylene glycol) (PPG) oligomer. The PPG-grafted polyimide precursor, poly((amic acid)-co-(amic ester)), was synthesized via partial esterification of poly(amic acid) derived from pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA) with bromo-terminated poly(propylene glycol) in the presence of K2CO3 in hexamethylphosphoramide and N-methylpyrrolidone. The precursor polymer film was spin-coated onto a glass substrate, then imidized at 200 °C under nitrogen, and subsequently the PPG graft was decomposed by heating the film at 300 °C for 9 h in air, resulting in the PMDA/ODA polyimide nanofoam. The precursor polymers, polyimides and foamed polyimides were characterized by a variety of techniques including 1H-NMR spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The homogeneously distributed nano-sized pores of 20–40 nm were observed by transmission electron microscopy (TEM) of the foamed polyimide. Copyright © 2004 Society of Chemical Industry

This paper proposes a 3 kW single-phase bi-directional multi-level converter (MLC) for charging/discharging an electric vehicle. The proposed topology is based on an H-bridge structure with four switches connected to DC-link. Based on a POD (phase opposition disposition) modulation method, a PWM method which requires only one carrier signal is used. The switching sequence to balance the capacitor voltage is also considered. Operating principle of the proposed converter is verified through simulation and experiment.