AIM:To evaluate the therapeutic usefulness and safety of endoscopic resection in patients with gastric ectopic pancreas.METHODS:A total of eight patients with ectopic pancreas were included.All of them underwent endos...AIM:To evaluate the therapeutic usefulness and safety of endoscopic resection in patients with gastric ectopic pancreas.METHODS:A total of eight patients with ectopic pancreas were included.All of them underwent endoscopic ultrasonography before endoscopic resection.Endo-scopic resection was performed by two methods:endo-scopic mucosal resection(EMR)by the injection-and-cut technique or endoscopic mucosal dissection(ESD).RESULTS:We planned to perform EMR in all eight cases but EMR was successful in only four cases.In the other four cases,saline spread into surrounding normal tissues and the lesions becameattened,which made it impossible to remove them by EMR.Inthose four cases,we performed ESD and removed the lesions without any complications.CONCLUSION:If conventional EMR is difficult to remove gastric ectopic pancreas,ESD is a feasible alternative method for successful removal.展开更多
The carbon(C) and nitrogen(N) storage capabilities of Pinus densiflora in six different stand ages(10,27,30,32,44,and 71 years old) were investigated in Korea.Thirty sample trees were destructively harvested and 12 we...The carbon(C) and nitrogen(N) storage capabilities of Pinus densiflora in six different stand ages(10,27,30,32,44,and 71 years old) were investigated in Korea.Thirty sample trees were destructively harvested and 12 were excavated.Samples from the above and belowground tree components,coarse woody debris(CWD),forest floor,and mineral soil(0-30 cm) were collected.Tree biomass was highest in the 71-year-old stand(202.8 t ha-1) and lowest in the 10-year-old stand(18.4 t ha-1).C and N storage in the mineral soil was higher in the 71-year-old stand than in the other stands,mainly due to higher soil C and N concentrations.Consequently,the total ecosystem C and N storage(tree+forest floor+CWD+soil) was positively correlated with stand age:increasing from a minimum in the 10 year old stand(18.8 t C ha-1 and 1.3 t N ha-1) to a maximum in the 71-year-old stand(201.4 t C ha-1 and 8.5 t N ha-1).The total ecosystem C storage showed a similar sigmoidal pattern to that of tree C storage as a function of the age-sequence,while N storage in the CWD,forest floor and mineral soil showed no significant temporal trends.Our results provide important insights that will increase our understanding of C and N storage in P.densiflora stands and our ability to predict changes according to stand age in the region.展开更多
Energy and environmental issues presently attract a great deal of scientific attention. Recently, two-dimensional MXenes and MXene-based nanomaterials have attracted increasing interest because of their unique propert...Energy and environmental issues presently attract a great deal of scientific attention. Recently, two-dimensional MXenes and MXene-based nanomaterials have attracted increasing interest because of their unique properties (e.g., remarkable safety, a very large interlayer spacing, environmental flexibility, a large surface area, and thermal conductivity). In 2011, multilayered MXenes (Ti3C2Tx, a new family of two-dimensional (2D) materials) produced by etching an A layer from a MAX phase of Ti3AlC2, were first described by researchers at Drexel University. The term “MXene” was coined to distinguish this new family of 2D materials from graphene, and applies to both the original MAX phases and MXenes fabricated from them. We present a comprehensive review of recent studies on energy and environmental applications of MXene and MXene-based nanomaterials, including energy conversion and storage, adsorption, membrane, photocatalysis, and antimicrobial. Future research needs are discussed briefly with current challenges that must be overcome before we completely understand the extraordinary properties of MXene and MXene-based nanomaterials.展开更多
Rectal cancer is a common cancer and a major cause of mortality in Western countries. Accurate staging is essential for determining the optimal treatment strategies and planning appropriate surgical procedures to cont...Rectal cancer is a common cancer and a major cause of mortality in Western countries. Accurate staging is essential for determining the optimal treatment strategies and planning appropriate surgical procedures to control rectal cancer. Endorectal ultrasonography (EUS) is suitable for assessing the extent of tumor invasion, particularly in early-stage or superficial rectal cancer cases. In advanced cases with distant metastases, computed tomography (CT) is the primary approach used to evaluate the disease. Magnetic resonance imaging (MRI) is often used to assess preoperative staging and the circumferential resection margin involvement, which assists in evaluating a patient’s risk of recurrence and their optimal therapeutic strategy. Positron emission tomography (PET)-CT may be useful in detecting occult synchronous tumors or metastases at the time of initial presentation. Restaging after neoadjuvant chemoradiotherapy (CRT) remains a challenge with all modalities because it is difficult to reliably differentiate between the tumor mass and other radiation-induced changes in the images. EUS does not appear to have a useful role in post-therapeutic response assessments. Although CT is most commonly used to evaluate treatment responses, its utility for identifying and following-up metastatic lesions is limited. Preoperative high-resolution MRI in combination with diffusion-weighted imaging, and/or PET-CT could provide valuable prognostic information for rectal cancer patients with locally advanced disease receiving preoperative CRT. Based on these results, we conclude that a combination of multimodal imaging methods should be used to precisely assess the restaging of rectal cancer following CRT.展开更多
This paper addresses the design of a biomimetic fish robot actuated by piezoeeramic actuators and the effect of artificial caudal fins on the fish robot＇s performance. The limited bending displacement produced by a l...This paper addresses the design of a biomimetic fish robot actuated by piezoeeramic actuators and the effect of artificial caudal fins on the fish robot＇s performance. The limited bending displacement produced by a lightweight piezocomposite actuator was amplified and transformed into a large tail beat motion by means of a linkage system. Caudal fins that mimic the shape of a mackerel fin were fabricated for the purpose of examining the effect of caudal fm characteristics on thrust production at an operating frequency range. The thickness distribution of a real mackerel＇s fin was measured and used to design artificial caudal fins. The thrust performance of the biomimetic fish robot propelled by fins of various thicknesses was examined in terms of the Strouhal number, the Froude number, the Reynolds number, and the power consumption. For the same fm area and aspect ratio, an artificial caudal fin with a distributed thickness shows the best forward speed and the least power consumption.展开更多
AIM:There is some evidence of functional superiority of colonic J-pouch over straight coloanal anastomosis (CM) in ultralow anterior resection (ULAR) or intersphincteric resection. On the assumption that colonic J-pou...AIM:There is some evidence of functional superiority of colonic J-pouch over straight coloanal anastomosis (CM) in ultralow anterior resection (ULAR) or intersphincteric resection. On the assumption that colonic J-pouch anal anastomosis is superior to straight CM in ULAR with upper sphincter excision (USE: excision of the upper part of the internal sphincter) for low-lying rectal cancer, we compare functional outcome of colonic J-pouch vsthe straight CM. METHODS: Fifty patients of one hundred and thirty-three rectal cancer patients in whom lower margin of the tumors were located between 3 and 5 cm from the anal verge received ULAR including USE from September 1998 to January 2002. Patients were randomized for reconstruction using either a straight (n = 26) or a colonic J-pouch anastomosis (n = 24) with a temporary diverting-loop ileostomy. All patients were followed-up prospectively by a standardized questionnaire [Fecal Inco-ntinence Severity Index (FISI) scores and Fecal Incontinence Quality of Life (FIQL) scales]. RESULTS: We found that, compared to straight anastomosis patients, the frequency of defecation was significantly lower in J-pouch anastomosis patients for 10 mo after ileostomy takedown. The FISI scores and FIQL scales were significantly better in J-pouch patients than in straight patients at both 3 and 12 mo after ileostomy takedown. Furthermore, we found that FISI scores highly correlated with FIQL scales. CONCLUSION: This study indicates that colonic J-pouch anal anastomosis decreases the severity of fecal incontinence and improves the quality of life for 10 mo after ileostomy takedown in patients undergoing ULAR with USE for low-lying rectal cancer.展开更多
BACKGROUND Despite advancements in operative technique and improvements in postoperative managements,postoperative pancreatic fistula(POPF)is a life-threatening complication following pancreatoduodenectomy(PD).There a...BACKGROUND Despite advancements in operative technique and improvements in postoperative managements,postoperative pancreatic fistula(POPF)is a life-threatening complication following pancreatoduodenectomy(PD).There are some reports to predict POPF preoperatively or intraoperatively,but the accuracy of those is questionable.Artificial intelligence(AI)technology is being actively used in the medical field,but few studies have reported applying it to outcomes after PD.AIM To develop a risk prediction platform for POPF using an AI model.METHODS Medical records were reviewed from 1769 patients at Samsung Medical Center who underwent PD from 2007 to 2016.A total of 38 variables were inserted into AI-driven algorithms.The algorithms tested to make the risk prediction platform were random forest(RF)and a neural network(NN)with or without recursive feature elimination(RFE).The median imputation method was used for missing values.The area under the curve(AUC)was calculated to examine the discriminative power of algorithm for POPF prediction.RESULTS The number of POPFs was 221(12.5%)according to the International Study Group of Pancreatic Fistula definition 2016.After median imputation,AUCs using 38 variables were 0.68±0.02 with RF and 0.71±0.02 with NN.The maximal AUC using NN with RFE was 0.74.Sixteen risk factors for POPF were identified by AI algorithm:Pancreatic duct diameter,body mass index,preoperative serum albumin,lipase level,amount of intraoperative fluid infusion,age,platelet count,extrapancreatic location of tumor,combined venous resection,co-existing pancreatitis,neoadjuvant radiotherapy,American Society of Anesthesiologists’score,sex,soft texture of the pancreas,underlying heart disease,and preoperative endoscopic biliary decompression.We developed a web-based POPF prediction platform,and this application is freely available at http://popfrisk.smchbp.org.CONCLUSION This study is the first to predict POPF with multiple risk factors using AI.This platform is reliable(AUC 0.74),so it could be used to select展开更多
AIM:To compare outcomes from radiofrequency ablation(RFA) and hepatectomy for treatment of colorectal liver metastasis(CRLM).METHODS:From January 2000 to December 2009,408 patients underwent curative intent treatment ...AIM:To compare outcomes from radiofrequency ablation(RFA) and hepatectomy for treatment of colorectal liver metastasis(CRLM).METHODS:From January 2000 to December 2009,408 patients underwent curative intent treatment for CRLM.We excluded patients using the criteria:size of CRLM > 3 cm,number of CRLM ≥ 5,percutaneous RFA,follow-up period < 12 mo,double primary cancer,or treatment with both RFA and hepatectomy.We matched 51 patients who underwent RFA with 102 patients who underwent hepatectomy by propensity scores.RESULTS:The median follow-up period was 45 mo(range,12 mo to 158 mo).Hepatic recurrence was more frequent in the RFA than the hepatectomy group(P = 0.021) although extrahepatic recurrence curves were similar(P = 0.716).Survival curves of hepatectomy group were better than that of RFA for multiple,large(> 2 cm) CRLM(P = 0.034).However,survival curves were similar for single or small(≤ 2 cm) CRLM(P = 0.714,P = 0.740).CONCLUSION:Hepatectomy is better than RFA for the treatment of CRLM.However,RFA might be suitable for selected patients with single,small(≤ 2 cm) CRLM.展开更多
AIM: To evaluate the ultrasonog raphy (EUS) features of gastric gastrointestinal stromal tumors (GISTs) as compared with gastric leiomyomas and then to determine the EUS features that could predict malignant GISTs.MET...AIM: To evaluate the ultrasonog raphy (EUS) features of gastric gastrointestinal stromal tumors (GISTs) as compared with gastric leiomyomas and then to determine the EUS features that could predict malignant GISTs.METHODS: We evaluated the endoscopic EUS features in 53 patients with gastric mesenchymal tumors conf irmed by histopathologic diagnosis. The GISTs were classif ied into benign and malignant groups according to the histological risk classif ication.RESULTS: Immunohistochemical analyses demon-strated 7 leiomyomas and 46 GISTs. Inhomogenicity, hyperechogenic spots, a marginal halo and higher echogenicity as compared with the surrounding muscle layer appeared more frequently in the GISTs than in the leiomyomas (P < 0.05). The presence of at least two of these four features had a sensitivity of 89.1% and a specifi city of 85.7% for predicting GISTs. Except for tumor size and irregularity of the border, most of the EUS features were not helpful for predicting the malignant potential of GISTs. On multivariate analysis, only the maximal diameter of the GISTs was an independent predictor. The optimal size for predicting malignant GISTs was 35 mm. The sensitivity and specificity using this value were 92.3% and 78.8%, respectively.CONCLUSION: EUS may help to differentiate gastric GISTs from gastric leiomyomas. Once GISTs are suspected, surgery should be considered if the size is greater than 3.5 cm.展开更多
AIM:To review the clinical course and the management of pseudoaneurysms post-pancreaticoduodenectomy.METHODS: Medical records of 907 patients who underwent pancreaticoduodenectomies from January 1995 to May 2007 were ...AIM:To review the clinical course and the management of pseudoaneurysms post-pancreaticoduodenectomy.METHODS: Medical records of 907 patients who underwent pancreaticoduodenectomies from January 1995 to May 2007 were evaluated retrospectively. The clinical course, management strategy, and outcome of ruptured pseudoaneurysms cases were analyzed.RESULTS: Twenty-seven (3.0%) of 907 cases had post-operative hemorrhage from ruptured pseudoan-eurysms. Pancreatic fistula was evident in 12 (44%) cases. Sentinel ble...展开更多
Nanoporous silicon is a promising anode material for high energy density batteries due to its high cycling stability and high tap density compared to other nanostructured anode materials.However,the high cost of synth...Nanoporous silicon is a promising anode material for high energy density batteries due to its high cycling stability and high tap density compared to other nanostructured anode materials.However,the high cost of synthesis and low yield of nanoporous silicon limit its practical application.Here,we develop a scalable,low-cost top-down process of controlled oxidation of Mg2Si in the air,followed by HCl removal of MgO to generate nanoporous silicon without the use of HF.By controlling the synthesis conditions,the oxygen content,grain size and yield of the porous silicon are simultaneously optimized from commercial standpoints.In situ environmental transmission electron microscopy reveals the reaction mechanism;the Mg2Si microparticle reacts with O2 to form MgO and Si,while preventing SiO2 formation.Owing to the low oxygen content and microscale secondary structure,the nanoporous silicon delivers a higher initial reversible capacity and initial Coulombic efficiency compared to commercial Si nanoparticles(3,033 mAh/g vs.2,418 mAh/g,84.3%vs.73.1%).Synthesis is highly scalable,and a yield of 90.4%is achieved for the porous Si nanostructure with the capability to make an excess of 10 g per batch.Our synthetic nanoporous silicon is promising for practical applications in next generation lithium-ion batteries.展开更多
AIM: To ascertain clinical outcome and complications of self-expandable metal stents for endoscopic palliation of patients with malignant obstruction of the gastrointestinal (GI) tract. METHODS: A retrospective review...AIM: To ascertain clinical outcome and complications of self-expandable metal stents for endoscopic palliation of patients with malignant obstruction of the gastrointestinal (GI) tract. METHODS: A retrospective review was performed throughout August 2000 to June 2005 of 53 patients with gastric outlet obstruction caused by stomach cancer. All patients had symptomatic obstruction including nausea, vomiting, and decreased oral intake. All received self-expandable metallic stents. RESULTS: Stent implantation was successful in all 53 (100%) patients. Relief of obstructive symptoms was achieved in 43 (81.1%) patients. No immediate stent-related complications were noted. Seventeen patients had recurrent obstruction (tumor ingrowth in 14 patients, tumor overgrowth in 1 patient, and partial distal stent migration in 2 patients). The mean survival was 145 d. Median stent patency time was 187 d. CONCLUSION: Endoscopic placement of self-expandable metallic stents is a safe and effective treatment for the palliation of patients with inoperable malignant gastric outlet obstruction caused by stomach cancer.展开更多
AIM:To investigate the relationship between Helicobacter pylori(H.pylori) seropositivity and the presence of microalbuminuria.METHODS:Between December 2003 and February 2010,asymptomatic individuals who visited the Se...AIM:To investigate the relationship between Helicobacter pylori(H.pylori) seropositivity and the presence of microalbuminuria.METHODS:Between December 2003 and February 2010,asymptomatic individuals who visited the Seoul National University Healthcare System Gangnam Center for a routine check-up and underwent tests for H.pylori immunoglobulin G antibodies and urinary albumin to creatinine ratio(UACR) were included.All study subjects completed a structured questionnaire,anthropometric measurements and laboratory tests.Anti-H.pylori immunoglobulin G was identified using an enzyme-linked immunosorbent assay kit.A random single-void urine sample,collected using a clean-catch technique,was obtained to determine the UACR.The presence of microalbuminuria was defined as a UACR from 30 to 300 μg/mg.The presence of diabetes mellitus(DM) was defined as either a fasting serum glucose level greater than or equal to 126 mg/dL or taking anti-diabetic medication.Multiple logistic regression analysis was performed to identify the risk factors.The dependent variable was microalbuminuria,and the independent variables were the other study variables.RESULTS:A total of 2716 subjects(male,71.8%;mean age,54.9 years) were included.Among them,224 subjects(8.2%) had microalbuminuria and 324 subjects(11.9%) had been diagnosed with DM.Subjects with microalbuminuria had a significantly higher H.pylori seropositivity rate than subjects without microalbuminuria(60.7% vs 52.8%,P = 0.024).Multivariate analysis after adjustment for age,body mass index(BMI),waist circumference,and glucose and triglyceride levels showed that H.pylori seropositivity was significantly associated with microalbuminuria [odds ratio(OR),1.40,95% CI,1.05-1.89,P = 0.024].After the data were stratified into cohorts by glucose levels(≤ 100 mg/dL,100 mg/dL < glucose < 126 mg/dL,and ≥ 126 mg/dL or history of DM),H.pylori seropositivity was found to be significantly associated with microalbuminuria in diabetic subjects after adjusting for age,BMI and serum creatinine level(展开更多
Carbazole moiety-based 2PACz([2-(9H-carbazol-9-yl)ethyl]phosphonic acid)self-assembled monolayers(SAMs)are excellent hole-selective contact(HSC)materials with abilities to excel the charge-transferdynamics of perovski...Carbazole moiety-based 2PACz([2-(9H-carbazol-9-yl)ethyl]phosphonic acid)self-assembled monolayers(SAMs)are excellent hole-selective contact(HSC)materials with abilities to excel the charge-transferdynamics of perovskite solar cells(PSCs).Herein,we report a facile but powerful method to functionalize the surface of 2PACz-SAM,by which reproducible,highly stable,high-efficiency wide-bandgap PSCs can be obtained.The 2PACz surface treatment with various donor number solvents improves assembly of 2PACz-SAM and leave residual surface-bound solvent molecules on 2PACz-SAM,which increases perovskite grain size,retards halide segregation,and accelerates hole extraction.The surface functionalization achieves a high power conversion efficiency(PCE)of 17.62%for a single-junction wide-bandgap(~1.77 e V)PSC.We also demonstrate a monolithic all-perovskite tandem solar cell using surfaceengineered HSC,showing high PCE of 24.66%with large open-circuit voltage of 2.008 V and high fillfactor of 81.45%.Our results suggest this simple approach can further improve the tandem device,when coupled with a high-performance narrow-bandgap sub-cell.展开更多
OBJECTIVE:To investigate the optimal timing and underlying mechanism of electroacupuncture(EA)at Baihui(GV 20)and Dazhui(GV 14)for improved long-term functional recovery after focal cerebral ischemia in a photothrombo...OBJECTIVE:To investigate the optimal timing and underlying mechanism of electroacupuncture(EA)at Baihui(GV 20)and Dazhui(GV 14)for improved long-term functional recovery after focal cerebral ischemia in a photothrombotic stroke mouse model.METHODS:Totally 50 adult male C57 BL/6 J mice were assigned into 5 groups:(a)the control group,sham-operated mice(n=10);(b)the vehicle group,focal cerebral ischemia induction without EA(n=10);(c)the acute EA group,mice received EA immediately post-ischemia,followed by once-daily treatments for 7 consecutive days(n=10);(d)the subacute EA group,mice received EA 4 days post-ischemia,followed by once-daily treatments for 7 consecutive days(n=10);(e)the delayed EA group.EA stimulation(2 Hz,2 V for 20 min)was applied to acupuncture points(acupoints),Baihui(GV 20)and Dazhui(GV 14),once a day for 7 consecutive days beginning immediately(acute treatment),4 d(subacute treatment)and 10 d(delayed treatment)after focal cerebral ischemia in C57 BL/6 J mice.Behavioral assessments were conducted 21 and 28 d post-ischemia and histopathological analyses were performed 28 days post-ischemia.RESULTS:The subacute EA treatment at Baihui(GV20)and Dazhui(GV 14)significantly improved functional recovery compared to the vehicle group 28 d after ischemic brain injury,although brain atrophy was not reduced.The number of Neu N+and Neu N+/Brd U+cells as well as GFAP intensity in the ipsilateral cortex were significantly increased in the subacute group compared to the vehicle group 28 d post-ischemia.We concluded that EA stimulation 4 d post-ischemia(subacute treatment)enhanced neurogenesis and astrogliosis,likely contributing to long-term functional recovery following focal cerebral ischemia.CONCLUSION:Our findings suggest that the timing of the EA therapy at Baihui(GV 20)and Dazhui(GV 14)determines the therapeutic effects in mice with focal cerebral ischemia induced by photothrombotic occlusion.展开更多
The morphology and electronic structure of a Li4Ti5012 anode are known to determine its electrical and electrochemical properties in lithium rechargeable batteries. Ag-Li4Ti5012 nanofibers have been rationally designe...The morphology and electronic structure of a Li4Ti5012 anode are known to determine its electrical and electrochemical properties in lithium rechargeable batteries. Ag-Li4Ti5012 nanofibers have been rationally designed and synthesized by an electrospinning technique to meet the requirements of one-dimensional （1D） morphology and superior electrical conductivity. Herein, we have found that the 1D Ag-Li4Ti5012 nanofibers show enhanced specific capacity, rate capability, and cycling stability compared to bare Li4Ti5012 nanofibers, due to the Ag nanoparticles （〈5 nm）, which are mainly distributed at interfaces between Li4Ti5O12 primary particles. This structural morphology gives rise to 20% higher rate capability than bare Li4Ti5O12 nanofibers by facilitating the charge transfer kinetics. Our findings provide an effective way to improve the electrochemical performance of Li4Ti5O12 anodes for lithium rechargeable batteries.展开更多
Standard triple therapy, consisting of a proton pump inhibitor, plus amoxicillin and clarithromycin, has been the most commonly used first-line treatment regimen for Helicobacter pylori (H. pylori) eradication for man...Standard triple therapy, consisting of a proton pump inhibitor, plus amoxicillin and clarithromycin, has been the most commonly used first-line treatment regimen for Helicobacter pylori (H. pylori) eradication for many years worldwide. However, as a result of increased resistance to antibiotics, H. pylori eradication rates with use of standard triple therapy have been declining and recently reached < 80% in many countries. Several new strategies to enhance the eradication rate of H. pylori have been studied. Currently, among the alternative first-line eradication regimens, concomitant and hybrid regimens have shown excellent results and could be the optimal treatment option. Although clinical usefulness of rescue therapy for patients in whom eradication of H. pylori with non-bismuth quadruple regimen has failed is unclear, levofloxacin-based quadruple therapy has shown promise as a rescue treatment. The choice of third-line therapy depends on factors such as the local pattern of antibiotic resistance, drug availability, and previous treatment. We hope that a simple method for detection of antibiotic susceptibility using polymerase chain reaction would be a possible alternative to administration of “tailored treatment” in the era of increasing prevalence of antimicrobial resistance.展开更多
AIM:To analyze the clinicopathologic characteristics of surgically resected gastric lymphoma patients. METHODS:We retrospectively analyzed 57 surgically resected gastric lymphoma patients,dividing them into 2 subgroup...AIM:To analyze the clinicopathologic characteristics of surgically resected gastric lymphoma patients. METHODS:We retrospectively analyzed 57 surgically resected gastric lymphoma patients,dividing them into 2 subgroups:Low grade MALToma (the LG group),High grade MALToma and Diffuse large B cell lymphoma (the HG group). RESULTS:The numbers of patients were:20 in the LG group, 37 in the HG group.The diagnostic rate of gastroscopy was 34.8% at primary diagnosis and 50% including differential diagnoses.The positive rates of Hpyloriwere similar between the 2 groups (68% vs77%).Multiple lesions were found in 19.3%.The proportion of mucosal and submucosal lesions was 80.0%(16/20) in the LG group,and 24.3%(9/37) in the HG group (P<0.001).Lymph node invasion rates were 10.5%(2/19) in the LG group and 44.1%(15/34) in the HG group (P=0.031).The numbers of recurred patients were none in the LG group,and 8 in the HG group.By univariant analysis,group (P=0.024) and TNM stage (stage Ⅰ,Ⅱ vs stages Ⅲ,Ⅳ,P=0.002) were found to be the significant risk factors.There was a tendency of higher recurrence rate in the subtotal gastrectomy group than in the total gastrectomy group (P=0.50). CONCLUSION:The HG groups had a more advanced stage and a higher recurrence rate than the LG group.Although there was no difference between subtotal and total gastrectomies,more careful assessments of multiplicities and radical resections with lymph node dissections seem to be needed because of multiplicity and LN invasion even in LG group.展开更多
Overall, this paper explains the related information about VTOL and trend of this technology worldwide. Also, it comes up with the distinction among VTOL and helicopter and fixed wing aircraft. This paper concentrates...Overall, this paper explains the related information about VTOL and trend of this technology worldwide. Also, it comes up with the distinction among VTOL and helicopter and fixed wing aircraft. This paper concentrates on domestic and international drones that utilize VTOL technology. Also, this paper gives the explanation about VTOL’s performance and object. Furthermore, this paper predicts the future of VTOL and which area this technology going to be used.展开更多
基金Supported by Pusan National University Research Grant for two years
文摘AIM:To evaluate the therapeutic usefulness and safety of endoscopic resection in patients with gastric ectopic pancreas.METHODS:A total of eight patients with ectopic pancreas were included.All of them underwent endoscopic ultrasonography before endoscopic resection.Endo-scopic resection was performed by two methods:endo-scopic mucosal resection(EMR)by the injection-and-cut technique or endoscopic mucosal dissection(ESD).RESULTS:We planned to perform EMR in all eight cases but EMR was successful in only four cases.In the other four cases,saline spread into surrounding normal tissues and the lesions becameattened,which made it impossible to remove them by EMR.Inthose four cases,we performed ESD and removed the lesions without any complications.CONCLUSION:If conventional EMR is difficult to remove gastric ectopic pancreas,ESD is a feasible alternative method for successful removal.
基金supported by research grants from the Korea Forest Research Institute (Grant No. S110708L0101111W)National Research Foundation of Korea (Grant Nos. R01-2006-000-10863-0 and A307-K001)
文摘The carbon(C) and nitrogen(N) storage capabilities of Pinus densiflora in six different stand ages(10,27,30,32,44,and 71 years old) were investigated in Korea.Thirty sample trees were destructively harvested and 12 were excavated.Samples from the above and belowground tree components,coarse woody debris(CWD),forest floor,and mineral soil(0-30 cm) were collected.Tree biomass was highest in the 71-year-old stand(202.8 t ha-1) and lowest in the 10-year-old stand(18.4 t ha-1).C and N storage in the mineral soil was higher in the 71-year-old stand than in the other stands,mainly due to higher soil C and N concentrations.Consequently,the total ecosystem C and N storage(tree+forest floor+CWD+soil) was positively correlated with stand age:increasing from a minimum in the 10 year old stand(18.8 t C ha-1 and 1.3 t N ha-1) to a maximum in the 71-year-old stand(201.4 t C ha-1 and 8.5 t N ha-1).The total ecosystem C storage showed a similar sigmoidal pattern to that of tree C storage as a function of the age-sequence,while N storage in the CWD,forest floor and mineral soil showed no significant temporal trends.Our results provide important insights that will increase our understanding of C and N storage in P.densiflora stands and our ability to predict changes according to stand age in the region.
文摘Energy and environmental issues presently attract a great deal of scientific attention. Recently, two-dimensional MXenes and MXene-based nanomaterials have attracted increasing interest because of their unique properties (e.g., remarkable safety, a very large interlayer spacing, environmental flexibility, a large surface area, and thermal conductivity). In 2011, multilayered MXenes (Ti3C2Tx, a new family of two-dimensional (2D) materials) produced by etching an A layer from a MAX phase of Ti3AlC2, were first described by researchers at Drexel University. The term “MXene” was coined to distinguish this new family of 2D materials from graphene, and applies to both the original MAX phases and MXenes fabricated from them. We present a comprehensive review of recent studies on energy and environmental applications of MXene and MXene-based nanomaterials, including energy conversion and storage, adsorption, membrane, photocatalysis, and antimicrobial. Future research needs are discussed briefly with current challenges that must be overcome before we completely understand the extraordinary properties of MXene and MXene-based nanomaterials.
基金Supported by A grant(CRI 13041-22)of the Chonnam National University Hospital Research Institute of Clinical Medicine
文摘Rectal cancer is a common cancer and a major cause of mortality in Western countries. Accurate staging is essential for determining the optimal treatment strategies and planning appropriate surgical procedures to control rectal cancer. Endorectal ultrasonography (EUS) is suitable for assessing the extent of tumor invasion, particularly in early-stage or superficial rectal cancer cases. In advanced cases with distant metastases, computed tomography (CT) is the primary approach used to evaluate the disease. Magnetic resonance imaging (MRI) is often used to assess preoperative staging and the circumferential resection margin involvement, which assists in evaluating a patient’s risk of recurrence and their optimal therapeutic strategy. Positron emission tomography (PET)-CT may be useful in detecting occult synchronous tumors or metastases at the time of initial presentation. Restaging after neoadjuvant chemoradiotherapy (CRT) remains a challenge with all modalities because it is difficult to reliably differentiate between the tumor mass and other radiation-induced changes in the images. EUS does not appear to have a useful role in post-therapeutic response assessments. Although CT is most commonly used to evaluate treatment responses, its utility for identifying and following-up metastatic lesions is limited. Preoperative high-resolution MRI in combination with diffusion-weighted imaging, and/or PET-CT could provide valuable prognostic information for rectal cancer patients with locally advanced disease receiving preoperative CRT. Based on these results, we conclude that a combination of multimodal imaging methods should be used to precisely assess the restaging of rectal cancer following CRT.
文摘This paper addresses the design of a biomimetic fish robot actuated by piezoeeramic actuators and the effect of artificial caudal fins on the fish robot＇s performance. The limited bending displacement produced by a lightweight piezocomposite actuator was amplified and transformed into a large tail beat motion by means of a linkage system. Caudal fins that mimic the shape of a mackerel fin were fabricated for the purpose of examining the effect of caudal fm characteristics on thrust production at an operating frequency range. The thickness distribution of a real mackerel＇s fin was measured and used to design artificial caudal fins. The thrust performance of the biomimetic fish robot propelled by fins of various thicknesses was examined in terms of the Strouhal number, the Froude number, the Reynolds number, and the power consumption. For the same fm area and aspect ratio, an artificial caudal fin with a distributed thickness shows the best forward speed and the least power consumption.
文摘AIM:There is some evidence of functional superiority of colonic J-pouch over straight coloanal anastomosis (CM) in ultralow anterior resection (ULAR) or intersphincteric resection. On the assumption that colonic J-pouch anal anastomosis is superior to straight CM in ULAR with upper sphincter excision (USE: excision of the upper part of the internal sphincter) for low-lying rectal cancer, we compare functional outcome of colonic J-pouch vsthe straight CM. METHODS: Fifty patients of one hundred and thirty-three rectal cancer patients in whom lower margin of the tumors were located between 3 and 5 cm from the anal verge received ULAR including USE from September 1998 to January 2002. Patients were randomized for reconstruction using either a straight (n = 26) or a colonic J-pouch anastomosis (n = 24) with a temporary diverting-loop ileostomy. All patients were followed-up prospectively by a standardized questionnaire [Fecal Inco-ntinence Severity Index (FISI) scores and Fecal Incontinence Quality of Life (FIQL) scales]. RESULTS: We found that, compared to straight anastomosis patients, the frequency of defecation was significantly lower in J-pouch anastomosis patients for 10 mo after ileostomy takedown. The FISI scores and FIQL scales were significantly better in J-pouch patients than in straight patients at both 3 and 12 mo after ileostomy takedown. Furthermore, we found that FISI scores highly correlated with FIQL scales. CONCLUSION: This study indicates that colonic J-pouch anal anastomosis decreases the severity of fecal incontinence and improves the quality of life for 10 mo after ileostomy takedown in patients undergoing ULAR with USE for low-lying rectal cancer.
基金Supported by the National Research Foundation of Korea grant funded by the Korea government(Ministry of Science and ICT),No.NRF-2019R1F1A1042156and the Bio&Medical Technology Development Program,No.NRF-2017M3A9E1064784.
文摘BACKGROUND Despite advancements in operative technique and improvements in postoperative managements,postoperative pancreatic fistula(POPF)is a life-threatening complication following pancreatoduodenectomy(PD).There are some reports to predict POPF preoperatively or intraoperatively,but the accuracy of those is questionable.Artificial intelligence(AI)technology is being actively used in the medical field,but few studies have reported applying it to outcomes after PD.AIM To develop a risk prediction platform for POPF using an AI model.METHODS Medical records were reviewed from 1769 patients at Samsung Medical Center who underwent PD from 2007 to 2016.A total of 38 variables were inserted into AI-driven algorithms.The algorithms tested to make the risk prediction platform were random forest(RF)and a neural network(NN)with or without recursive feature elimination(RFE).The median imputation method was used for missing values.The area under the curve(AUC)was calculated to examine the discriminative power of algorithm for POPF prediction.RESULTS The number of POPFs was 221(12.5%)according to the International Study Group of Pancreatic Fistula definition 2016.After median imputation,AUCs using 38 variables were 0.68±0.02 with RF and 0.71±0.02 with NN.The maximal AUC using NN with RFE was 0.74.Sixteen risk factors for POPF were identified by AI algorithm:Pancreatic duct diameter,body mass index,preoperative serum albumin,lipase level,amount of intraoperative fluid infusion,age,platelet count,extrapancreatic location of tumor,combined venous resection,co-existing pancreatitis,neoadjuvant radiotherapy,American Society of Anesthesiologists’score,sex,soft texture of the pancreas,underlying heart disease,and preoperative endoscopic biliary decompression.We developed a web-based POPF prediction platform,and this application is freely available at http://popfrisk.smchbp.org.CONCLUSION This study is the first to predict POPF with multiple risk factors using AI.This platform is reliable(AUC 0.74),so it could be used to select
文摘AIM:To compare outcomes from radiofrequency ablation(RFA) and hepatectomy for treatment of colorectal liver metastasis(CRLM).METHODS:From January 2000 to December 2009,408 patients underwent curative intent treatment for CRLM.We excluded patients using the criteria:size of CRLM > 3 cm,number of CRLM ≥ 5,percutaneous RFA,follow-up period < 12 mo,double primary cancer,or treatment with both RFA and hepatectomy.We matched 51 patients who underwent RFA with 102 patients who underwent hepatectomy by propensity scores.RESULTS:The median follow-up period was 45 mo(range,12 mo to 158 mo).Hepatic recurrence was more frequent in the RFA than the hepatectomy group(P = 0.021) although extrahepatic recurrence curves were similar(P = 0.716).Survival curves of hepatectomy group were better than that of RFA for multiple,large(> 2 cm) CRLM(P = 0.034).However,survival curves were similar for single or small(≤ 2 cm) CRLM(P = 0.714,P = 0.740).CONCLUSION:Hepatectomy is better than RFA for the treatment of CRLM.However,RFA might be suitable for selected patients with single,small(≤ 2 cm) CRLM.
基金Supported by A Medical Research Institute Grant (2008-1)Pusan National University and a grant from the National R&D Program for Cancer Control, Ministry for Health, Welfare and Family affairs, Republic of Korea (0920050)
文摘AIM: To evaluate the ultrasonog raphy (EUS) features of gastric gastrointestinal stromal tumors (GISTs) as compared with gastric leiomyomas and then to determine the EUS features that could predict malignant GISTs.METHODS: We evaluated the endoscopic EUS features in 53 patients with gastric mesenchymal tumors conf irmed by histopathologic diagnosis. The GISTs were classif ied into benign and malignant groups according to the histological risk classif ication.RESULTS: Immunohistochemical analyses demon-strated 7 leiomyomas and 46 GISTs. Inhomogenicity, hyperechogenic spots, a marginal halo and higher echogenicity as compared with the surrounding muscle layer appeared more frequently in the GISTs than in the leiomyomas (P < 0.05). The presence of at least two of these four features had a sensitivity of 89.1% and a specifi city of 85.7% for predicting GISTs. Except for tumor size and irregularity of the border, most of the EUS features were not helpful for predicting the malignant potential of GISTs. On multivariate analysis, only the maximal diameter of the GISTs was an independent predictor. The optimal size for predicting malignant GISTs was 35 mm. The sensitivity and specificity using this value were 92.3% and 78.8%, respectively.CONCLUSION: EUS may help to differentiate gastric GISTs from gastric leiomyomas. Once GISTs are suspected, surgery should be considered if the size is greater than 3.5 cm.
基金Supported by Grants from IN-SUNG Foundation for Medical Research (C-A9-810-1)
文摘AIM:To review the clinical course and the management of pseudoaneurysms post-pancreaticoduodenectomy.METHODS: Medical records of 907 patients who underwent pancreaticoduodenectomies from January 1995 to May 2007 were evaluated retrospectively. The clinical course, management strategy, and outcome of ruptured pseudoaneurysms cases were analyzed.RESULTS: Twenty-seven (3.0%) of 907 cases had post-operative hemorrhage from ruptured pseudoan-eurysms. Pancreatic fistula was evident in 12 (44%) cases. Sentinel ble...
基金This work was supported by Samsung SDI.Part of this work was performed at the Stanford Nano Shared Facilities(SNSF)Stanford Nanofabrication Facility(SNF).
文摘Nanoporous silicon is a promising anode material for high energy density batteries due to its high cycling stability and high tap density compared to other nanostructured anode materials.However,the high cost of synthesis and low yield of nanoporous silicon limit its practical application.Here,we develop a scalable,low-cost top-down process of controlled oxidation of Mg2Si in the air,followed by HCl removal of MgO to generate nanoporous silicon without the use of HF.By controlling the synthesis conditions,the oxygen content,grain size and yield of the porous silicon are simultaneously optimized from commercial standpoints.In situ environmental transmission electron microscopy reveals the reaction mechanism;the Mg2Si microparticle reacts with O2 to form MgO and Si,while preventing SiO2 formation.Owing to the low oxygen content and microscale secondary structure,the nanoporous silicon delivers a higher initial reversible capacity and initial Coulombic efficiency compared to commercial Si nanoparticles(3,033 mAh/g vs.2,418 mAh/g,84.3%vs.73.1%).Synthesis is highly scalable,and a yield of 90.4%is achieved for the porous Si nanostructure with the capability to make an excess of 10 g per batch.Our synthetic nanoporous silicon is promising for practical applications in next generation lithium-ion batteries.
文摘AIM: To ascertain clinical outcome and complications of self-expandable metal stents for endoscopic palliation of patients with malignant obstruction of the gastrointestinal (GI) tract. METHODS: A retrospective review was performed throughout August 2000 to June 2005 of 53 patients with gastric outlet obstruction caused by stomach cancer. All patients had symptomatic obstruction including nausea, vomiting, and decreased oral intake. All received self-expandable metallic stents. RESULTS: Stent implantation was successful in all 53 (100%) patients. Relief of obstructive symptoms was achieved in 43 (81.1%) patients. No immediate stent-related complications were noted. Seventeen patients had recurrent obstruction (tumor ingrowth in 14 patients, tumor overgrowth in 1 patient, and partial distal stent migration in 2 patients). The mean survival was 145 d. Median stent patency time was 187 d. CONCLUSION: Endoscopic placement of self-expandable metallic stents is a safe and effective treatment for the palliation of patients with inoperable malignant gastric outlet obstruction caused by stomach cancer.
文摘AIM:To investigate the relationship between Helicobacter pylori(H.pylori) seropositivity and the presence of microalbuminuria.METHODS:Between December 2003 and February 2010,asymptomatic individuals who visited the Seoul National University Healthcare System Gangnam Center for a routine check-up and underwent tests for H.pylori immunoglobulin G antibodies and urinary albumin to creatinine ratio(UACR) were included.All study subjects completed a structured questionnaire,anthropometric measurements and laboratory tests.Anti-H.pylori immunoglobulin G was identified using an enzyme-linked immunosorbent assay kit.A random single-void urine sample,collected using a clean-catch technique,was obtained to determine the UACR.The presence of microalbuminuria was defined as a UACR from 30 to 300 μg/mg.The presence of diabetes mellitus(DM) was defined as either a fasting serum glucose level greater than or equal to 126 mg/dL or taking anti-diabetic medication.Multiple logistic regression analysis was performed to identify the risk factors.The dependent variable was microalbuminuria,and the independent variables were the other study variables.RESULTS:A total of 2716 subjects(male,71.8%;mean age,54.9 years) were included.Among them,224 subjects(8.2%) had microalbuminuria and 324 subjects(11.9%) had been diagnosed with DM.Subjects with microalbuminuria had a significantly higher H.pylori seropositivity rate than subjects without microalbuminuria(60.7% vs 52.8%,P = 0.024).Multivariate analysis after adjustment for age,body mass index(BMI),waist circumference,and glucose and triglyceride levels showed that H.pylori seropositivity was significantly associated with microalbuminuria [odds ratio(OR),1.40,95% CI,1.05-1.89,P = 0.024].After the data were stratified into cohorts by glucose levels(≤ 100 mg/dL,100 mg/dL < glucose < 126 mg/dL,and ≥ 126 mg/dL or history of DM),H.pylori seropositivity was found to be significantly associated with microalbuminuria in diabetic subjects after adjusting for age,BMI and serum creatinine level(
基金supported by the National Research Foundation of Korea (NRF)the Ministry of Science,ICT (2022M3J1A1085285,2019R1A2C1084010,and 2022R1A2C2006532)the Korea Electric Power Corporation (R20XO02-1)。
文摘Carbazole moiety-based 2PACz([2-(9H-carbazol-9-yl)ethyl]phosphonic acid)self-assembled monolayers(SAMs)are excellent hole-selective contact(HSC)materials with abilities to excel the charge-transferdynamics of perovskite solar cells(PSCs).Herein,we report a facile but powerful method to functionalize the surface of 2PACz-SAM,by which reproducible,highly stable,high-efficiency wide-bandgap PSCs can be obtained.The 2PACz surface treatment with various donor number solvents improves assembly of 2PACz-SAM and leave residual surface-bound solvent molecules on 2PACz-SAM,which increases perovskite grain size,retards halide segregation,and accelerates hole extraction.The surface functionalization achieves a high power conversion efficiency(PCE)of 17.62%for a single-junction wide-bandgap(~1.77 e V)PSC.We also demonstrate a monolithic all-perovskite tandem solar cell using surfaceengineered HSC,showing high PCE of 24.66%with large open-circuit voltage of 2.008 V and high fillfactor of 81.45%.Our results suggest this simple approach can further improve the tandem device,when coupled with a high-performance narrow-bandgap sub-cell.
基金Supported by a 2-Year Research Grant of Pusan National University
文摘OBJECTIVE:To investigate the optimal timing and underlying mechanism of electroacupuncture(EA)at Baihui(GV 20)and Dazhui(GV 14)for improved long-term functional recovery after focal cerebral ischemia in a photothrombotic stroke mouse model.METHODS:Totally 50 adult male C57 BL/6 J mice were assigned into 5 groups:(a)the control group,sham-operated mice(n=10);(b)the vehicle group,focal cerebral ischemia induction without EA(n=10);(c)the acute EA group,mice received EA immediately post-ischemia,followed by once-daily treatments for 7 consecutive days(n=10);(d)the subacute EA group,mice received EA 4 days post-ischemia,followed by once-daily treatments for 7 consecutive days(n=10);(e)the delayed EA group.EA stimulation(2 Hz,2 V for 20 min)was applied to acupuncture points(acupoints),Baihui(GV 20)and Dazhui(GV 14),once a day for 7 consecutive days beginning immediately(acute treatment),4 d(subacute treatment)and 10 d(delayed treatment)after focal cerebral ischemia in C57 BL/6 J mice.Behavioral assessments were conducted 21 and 28 d post-ischemia and histopathological analyses were performed 28 days post-ischemia.RESULTS:The subacute EA treatment at Baihui(GV20)and Dazhui(GV 14)significantly improved functional recovery compared to the vehicle group 28 d after ischemic brain injury,although brain atrophy was not reduced.The number of Neu N+and Neu N+/Brd U+cells as well as GFAP intensity in the ipsilateral cortex were significantly increased in the subacute group compared to the vehicle group 28 d post-ischemia.We concluded that EA stimulation 4 d post-ischemia(subacute treatment)enhanced neurogenesis and astrogliosis,likely contributing to long-term functional recovery following focal cerebral ischemia.CONCLUSION:Our findings suggest that the timing of the EA therapy at Baihui(GV 20)and Dazhui(GV 14)determines the therapeutic effects in mice with focal cerebral ischemia induced by photothrombotic occlusion.
文摘The morphology and electronic structure of a Li4Ti5012 anode are known to determine its electrical and electrochemical properties in lithium rechargeable batteries. Ag-Li4Ti5012 nanofibers have been rationally designed and synthesized by an electrospinning technique to meet the requirements of one-dimensional （1D） morphology and superior electrical conductivity. Herein, we have found that the 1D Ag-Li4Ti5012 nanofibers show enhanced specific capacity, rate capability, and cycling stability compared to bare Li4Ti5012 nanofibers, due to the Ag nanoparticles （〈5 nm）, which are mainly distributed at interfaces between Li4Ti5O12 primary particles. This structural morphology gives rise to 20% higher rate capability than bare Li4Ti5O12 nanofibers by facilitating the charge transfer kinetics. Our findings provide an effective way to improve the electrochemical performance of Li4Ti5O12 anodes for lithium rechargeable batteries.
文摘Standard triple therapy, consisting of a proton pump inhibitor, plus amoxicillin and clarithromycin, has been the most commonly used first-line treatment regimen for Helicobacter pylori (H. pylori) eradication for many years worldwide. However, as a result of increased resistance to antibiotics, H. pylori eradication rates with use of standard triple therapy have been declining and recently reached < 80% in many countries. Several new strategies to enhance the eradication rate of H. pylori have been studied. Currently, among the alternative first-line eradication regimens, concomitant and hybrid regimens have shown excellent results and could be the optimal treatment option. Although clinical usefulness of rescue therapy for patients in whom eradication of H. pylori with non-bismuth quadruple regimen has failed is unclear, levofloxacin-based quadruple therapy has shown promise as a rescue treatment. The choice of third-line therapy depends on factors such as the local pattern of antibiotic resistance, drug availability, and previous treatment. We hope that a simple method for detection of antibiotic susceptibility using polymerase chain reaction would be a possible alternative to administration of “tailored treatment” in the era of increasing prevalence of antimicrobial resistance.
文摘AIM:To analyze the clinicopathologic characteristics of surgically resected gastric lymphoma patients. METHODS:We retrospectively analyzed 57 surgically resected gastric lymphoma patients,dividing them into 2 subgroups:Low grade MALToma (the LG group),High grade MALToma and Diffuse large B cell lymphoma (the HG group). RESULTS:The numbers of patients were:20 in the LG group, 37 in the HG group.The diagnostic rate of gastroscopy was 34.8% at primary diagnosis and 50% including differential diagnoses.The positive rates of Hpyloriwere similar between the 2 groups (68% vs77%).Multiple lesions were found in 19.3%.The proportion of mucosal and submucosal lesions was 80.0%(16/20) in the LG group,and 24.3%(9/37) in the HG group (P<0.001).Lymph node invasion rates were 10.5%(2/19) in the LG group and 44.1%(15/34) in the HG group (P=0.031).The numbers of recurred patients were none in the LG group,and 8 in the HG group.By univariant analysis,group (P=0.024) and TNM stage (stage Ⅰ,Ⅱ vs stages Ⅲ,Ⅳ,P=0.002) were found to be the significant risk factors.There was a tendency of higher recurrence rate in the subtotal gastrectomy group than in the total gastrectomy group (P=0.50). CONCLUSION:The HG groups had a more advanced stage and a higher recurrence rate than the LG group.Although there was no difference between subtotal and total gastrectomies,more careful assessments of multiplicities and radical resections with lymph node dissections seem to be needed because of multiplicity and LN invasion even in LG group.
文摘Overall, this paper explains the related information about VTOL and trend of this technology worldwide. Also, it comes up with the distinction among VTOL and helicopter and fixed wing aircraft. This paper concentrates on domestic and international drones that utilize VTOL technology. Also, this paper gives the explanation about VTOL’s performance and object. Furthermore, this paper predicts the future of VTOL and which area this technology going to be used.
