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Recent breakthroughs in the sintering of aluminium alloys under nitrogen have opened the way for the in-situ fabrication of Al-AlN composites in a controllable and reproducible fashion over a wide range of volume fractions of AlN. This work reviews the fundamentals for the in-situ fabrication of the Al-AlN composites from metal powders and highlights their technical potential for niche applications because of their excellent resistance to cavitation erosion in water and their unusually low friction coefficient under oil lubrication.

In order to improve and evaluate the wear behavior of the sintered magnesium materials under dry sliding conditions, the effect of carbon nanotubes (CNTs) and Mg2Si/MgO compounds, which were reinforcements of the sintered material, on the friction coefficient and wear loss under dry conditions was discussed. One of the raw materials was amorphous and porous silica particles originated from rice husks, which were coated with CNTs and contained nanotubes in the pores. The in situ synthesis of Mg2Si and MgO via deoxidization and oxidation reaction occurred from the elemental mixture of pure magnesium and CNT-SiO2 composite particles via the spark plasma sintering process. The friction coefficient of the composite material was low and stable because of no adhesion and stick-slip phenomenon in contacting with the SUS304 stainless steel ball as a counter material. The wear rate of sintered magnesium materials decreases in increasing the content of CNTs and Mg2Si. The friction coefficient was proportional to the total wear loss of magnesium materials. These results were due to both of the defensive by hard Mg2Si dispersoids and self-lubricant effect by network nanotubes on the sliding surface.

By using the solid-state reaction of rice husk silica particles with magnesium powder, P/M magnesium based composites dispersed with the magnesium silicide (Mg2Si) and magnesium oxide (MgO) were fabricated. High-purity silica particles were originated from rice husks, one of the major agricultural wastes, via the citric acid leaching treatment and combustion in air. The effects of the silica particle characteristics such as size, crystalline and porous structures, on the reactivity of silica and magnesium to synthesize Mg2Si intermetallics were discussed. As the results by DTA and XRD analysis, finer silica particles were more effective for the solid-state reaction at low temperature due to the increase of their surface area contacted with magnesium powder. Amorphous silica was also more useful for this reaction than the crystalline one. The reactivity of rice husk silica was superior to that of the conventional mineral silica particles not only because of its amorphous structure but also the larger specific surface area due to their pore structures. In the case of the green compact of the elemental mixture of silica particles and Mg powder, the silica particle size was not effective on the reactivity because the coarse particles were fractured into fine ones by cold compaction. The distribution of Mg2Si intermetallics of magnesium powder composites consolidated by SPS process was investigated by XRD and SEM-EDS analysis. When the sintering temperature was over the exothermic temperature of the mixture in the DTA profile, the synthesis of Mg2Si completely occurred during sintering. The sinterability of the elemental mixture powder was improved when employing the amorphous rice husk silica particles. The density and hardness of their composites sintered over the ignition temperature of the DTA profile were remarkably high because of the good densification by the high reactivity and the distribution of Mg2Si hard compounds.

The cavitation erosion resistance of P/M aluminum alloy sintered composite with AlN dispersoids, prepared via the in situ synthesis and the conventional premixing process, was evaluated by using a magnetostrictive-vibration type equipment. In situ synthesized AlN particles were effective for the improvement of the erosion resistance of the composite because of their good bonding with the aluminum matrix. The additive AlN by the premixing process were easily detached from the specimen surface due to the insufficient coherence with the matrix, and caused the poor resistance. The cavitation resistance also depended on the porosity of the sintered composite. The continuously opened pores accelerated the wear phenomena by the cavitation due to the high pressure attack on the primary particle boundaries of sintered materials in the collapse of the bubbles.

A powder metallurgy (P/M) titanium matrix composite (TMC) reinforced with low cost carbon black was prepared by spark plasma sintering (SPS) and hot extrusion. Carbon black particles were added for the in situ formation of TiC dispersoids during the SPS process. Two kinds of titanium (Ti) powders, sponge and fine Ti, were coated with carbon black particles via a wet process using a zwitterionic solution containing carbon black spheres. The distribution of the particles on the Ti powder surface before the consolidation process was imaged using scanning electron microscopy (SEM). We evaluated the microstructure and mechanical properties of extruded pure Ti matrix composites reinforced with TiC particles. The morphology and distribution of the in situ TiC phases were investigated using optical microscopy and SEM with the help of an EDS analyzer. The mechanical properties of these composites were remarkably improved by adding a small amount of carbon black at 0:07� 0:16 mass%. The increases in the yield stress of the extruded sponge and fine TMC were 70.0 and 291 MPa, while the tensile strength increases were 67 and 231 MPa, respectively, compared to those of extruded pure Ti with no reinforcement. Finally, the fractured surfaces of TMC specimens after tensile testing were observed. The benefits of the wet process and the use of carbon black additives are discussed in detail. [doi:10.2320/matertrans.MA200906]

The environmentally benign, harmless to human, and economically effective process to produce high-purity amorphous SiO2 materials from rice husks has been established by using a carboxylic acid leaching, not the conventional strong acids. TG-DTA measurement and GCMS analysis indicated that the leaching was effective for the hydrolysis of celluloses and hemicelluloses contained in rice husks at 473–873 K, which produced the same results in using the conventional sulfuric acid. In particular, the formation of furfurals and levoglucosans occurred via the hydrolysis at 473 K and 673 K, respectively, when using rice husks leached by citric acid solutions. The metallic impurities could be also removed from the husks via a chelate reaction between carboxyl groups (–COOH) and the metal elements. Concerning the burning conditions of rice husks after the acid leaching, it was necessary to supply a suitable amount of air to completely combust organics; for example, it required air supplement of 50 mL/min or more. High-purity amorphous silica materials with 99 wt% or more were prepared from rice husks by applying the citric acid leaching treatment and burning process at 1073 K in air.

A method for practical preparation of pinacolborane from borane-diethylaniline and pinacol was newly developed. Aromatic C–H borylation of arenes with pinacolborane or bis(pinacolato)diboron catalyzed by 1/2[Ir(OMe)(COD)]2-(4,4′-di-tert-butyl-2,2′-bipyridine) at 25 °C in hexane to give arylboronic esters was directly followed by cross-coupling with aromatic bromides at 60 °C in the presence of PdCl2(dppf) (3.0 mol %) and K3PO4 in DMF. This one-pot, two-step procedure provided a variety of unsymmetrical biaryls in high yields.

Characteristics of 60Cu-40Zn brass powder compacts and their extruded materials were investigated. In 60Cu-40Zn brass powder billets consolidated by spark sintering, no vaporization of zinc occurred, and sintered billets with a high density over 99.9 % were obtained. These billets also had high tensile strength and elongation as well as cast brass ingots with the same composition. By the conditions of spark sintering; pressure of 40 MPa, temperature of 1053 K, sintering time of 1.8 ks, the extruded material of 60Cu-40Zn brass powder had an elongation over 50 %. Deformability for collapse test of the pipe extruded specimens also was high by spark sintering because of increasing α phase in extruded materials.

Microstructural and electrical properties of Cu-chromium alloy (Cu-Cr) dispersed with vapor-grown carbon fiber (VGCF) prepared by powder metallurgy (P/M) process have been investigated. Cu-0.7 mass% Cr pre-alloyed powder (Cu-Cr) made by water atomization process was used as raw materials, which contained solid solute Cr elements in Cu matrix. The alloy powder coated with un-bundled VGCF by using oil coating process was consolidated at 1223 K in vacuum by spark plasma sintering, and then extruded at 1073 K. The extruded Cu-Cr alloy (monolithic alloy) had 209.3 MPa YS and 80.4 IACS% conductivity. The extruded Cu-Cr with 0.1 mass% VGCF composites revealed a small decrease of YS compared to the monolithic Cu-Cr alloy. On the other hand, the composite had a higher electrical conductivity than that of the monolithic alloy. For example, Cu-Cr with 0.1 mass% VGCF composite sintered for 5 h showed 182.7 MPa YS and 89.7 IACS% conductivity. In the case of Cu-Cr with VGCFs composites, the Cr concentration was observed around VGCF by SEM-EDS analysis, where Cr23C6 compounds were detected by TEM observation. The amount of Cr solid solution in the matrix of the Cu-Cr composites alloy was about 50% compared to the monolithic Cu-Cr sintered alloy, and resulted in the remarkable increment of the electrical conductivity., {"references":["A. Lee, N. Grant. Properties of Two High Strength, High Temperature,\nHigh Conductivity Cu Base Alloys. Materials Science and Engineering,\n60, 213-223 (1983).","N. Khandoker et al. \"Tensile Strength of Spinnable Multiwall Carbon\nNanotubes\", Procedia Engineering, 10, 2572-2578 (2011).","S. Xie et al., \"Mechanical and Physical Properties on Carbon Nanotube\",\nJournal of Physics and Chemistry of Solids, 61, 1153-1158 (2000).","K. Kondoh et al., \"Microstructural and Mechanical Analysis of Carbon\nNanotube Reinforced Magnesium Alloy Powder Composites\", Materials\nScience & Engineering A, 527, 4103-4108 (2010).","S. Li et al., \"Powder Metallurgy Ti-TiC Metal Matrix Composites\nPrepared by In-situ Reactive Processing of Ti-VGCFs System\", Carbon,\n61, 216-228 (2013).","Y. Shimizu et al., \"Multi-Walled Carbon Nanotube-Reinforced\nMagnesium Alloy Composites\", Scripta Materialia, 58, 267-270 (2008).","D. Laughlin, J. Cahn, \"Spinodal Decomposition in Age Hardening\nCu-Titanium Alloys\", Acta Materialia, 23, 329-339 (1975).","A. Poter, A. Thompson, \"On the Mechanism of Precipitation\nStrengthening in Cu-Ti Alloys\", Scripta Materialia, 18, 1185-1188\n(1984).","K. Maki et al., \"Solid-solution Cu alloys with high strength and high\nelectrical conductivity\", Scripta Materialia, 68 (2013), 777-780.\n[10] S. Nagarjuna et al., \"Effect of Prior Cold Work on Mechanical Properties,\nElectrical Conductivity and Microstructure of Aged Cu-Ti Alloys\",\nJournal of Materials Science, 34, 2929-2942 (1999).\n[11] S. Nagarjuna et al., \"On the Variation of Mechanical Properties with\nSolute Content in Cu-Ti Alloys\", Materials Science and Engineering A,\n259, 34-42 (1999).\n[12] S. Semboshi et al., \"Microstructural Evolution of Cu-1 at % Ti Alloy aged\nin a Hydrogen Atmosphere and Its Relation with the Electrical\nConductivity\", Ultramicroscopy, 109, 593-598 (2009).\n[13] S. Suzuki et al., \"Electrical and Thermal Conductivities in Quenched and\nAged High-Purity Cu-Ti Alloys\", Scripta Materialia, 48, 431-435 (2003).\n[14] T. Oku et al., \"Effects of Titanium Addition on the Microstructure of\nCarbon/Cu Composite Materials\", Solid State Communications, 141,\n132-135 (2007).\n[15] H. Imai et al., \"Microstructural and Electrical Properties of Cu-titanium\nAlloy Dispersed with Carbon Nanotubes via Powder Metallurgy\nProcess\", Materials Transactions, 55, 3, 522-527, (2014).\n[16] H. Imai et al., \"Effect of Chromium Precipitation on Machinability of\nSintered Brass Alloys Dispersed with Graphite Particles\", Materials\nTransactions, 52, 7, 1426-1430, (2011).\n[17] M.S. Dresselhaus et al., \"Raman Spectroscopy of Carbon Nanotubes,\"\nPhysics Reports, 409, 47-99, (2005).\n[18] M. Small et al. \"Calculation and evaluation of the Gibbs energies of\nformation of Cr3C2, Cr7C3, and Cr23C6\", Metallurgical and Materials\nTransaction A, 12, 1389-1396, (1981)."]}

Background and Aims Balloon enteroscopy–assisted ERCP has provided a marked improvement in the success rate of reaching the papilla and consecutive ERCP procedures in patients with surgically altered anatomy in the Roux-en-Y reconstruction setting. However, limited data are available on the outcome of balloon enteroscopy–assisted ERCP in patients with Roux-en-Y anatomy who have naive papillae. We retrospectively evaluated the feasibility of balloon enteroscopy–assisted ERCP in Roux-en-Y reconstruction after total or subtotal gastrectomy (RYG) with native papillae. Methods We performed 123 ERCP procedures in 109 patients with RYG. Among these patients, 90 consecutive ERCPs in 90 patients with native papillae were included. When selective biliary cannulation failed, the double-guidewire technique, the precut technique, or the rendezvous technique were performed as advanced cannulation methods. Results The overall success rate of reaching the papilla was 93.5% (115/123). The total procedure success rate was 88.1% (96/109). The adverse event rate was 7.3% (8/109). The success rate of the standard cannulation of the intact papilla was 67.8% (61/90). The final cannulation success rate was 95.6% (86/90) by using advanced cannulation methods. Conclusions Standard cannulation of the intact papilla in RYG cases remains challenging and uncertain. The use of various advanced cannulation methods improves the deep cannulation rate. Once selective cannulation succeeds, the treatment success rate is very high.

In this experiment, TILOP-45 commercially pure titanium powder was mixed with vapor grown carbon fibers (VGCF) to form a 200 g 0.5 wt. % VGCF solution. After adding 0.15 grams of cle-safe oil, a rocking mill shook the sample at 60.0 Hz for 2 hours, resulting in satisfactory dispersion of VGCF on the titanium powder surface. The powder solution was compacted by spark plasma sintering (SPS) and hot extruded. The SPS temperature was set to either 800 °C or 1,000 °C and the pressure to 35 kN. Using an extrusion ratio of 13:1 and ram speed of 3 mm/s, the titanium billet, preheated to either 800 °C or 1,000 °C, was deformed to a 10 mm diameter rod. All four permutations of SPS and extrusion temperatures were tested. Microstructure, grain size, hardness, and oxygen/nitrogen/carbon content were observed. Also, a UTS experiment was done followed by SEM observations of the fractured surfaces.

Introduction: Biliary stricture can occur following surgeries of the biliary tract and can cause biliary congestion and cholangitis. Recently, fully covered self-expandable metal stent (FCSEMS) has been utilized for postoperative hilar and anastomotic strictures that have conventionally been considered difficult to treat. On the other hand, there is no solid evidence regarding optimal metal stent placement period. Method: Retrospective review of patients treated for postoperative benign biliary stricture using a FCSEMS at our hospital between 2013 and 2015. Results: We performed a total of 14 metal stent placements for 12 patients with postoperative benign biliary stricture. In all the patients, the metal stents were placed endoscopically and removed safely after the placement. The mean duration of stent placement was 47.9 days (28-144), and there was no retrograde cholangitis observed during metal stent placement. Following metal stent removal, the stricture improved in 9 patients. Recurrence developed in 3 patients, recurring bile duct stones in 2 patients, and cholangitis in 1 patient. Adverse events included post-ERCP pancreatitis in 2 patients, which was alleviated by stent removal the following day and conservative treatment in 1 patient, and conservative treatment only in the other patient. Distal stent migration was observed in 2 patients. Conclusion: The present results suggest that stricture improvement can be expected in a shorter period by metal stent placement in patients with refractory postoperative biliary stricture. In patients with bile duct stones, lithectomy can be safely and effectively performed following metal stent expansion; however, further studies are required.

Hydroboration of terminal and internal alkenes with N,N′,N″-trimethyl- and N,N′,N″-triethylborazine was carried out at 50 °C in the presence of a rhodium(I) catalyst. Addition of dppb or DPEphos (1 equiv.) to RhH(CO)(PPh3)3 gave the best catalyst for hydroboration of ethylene at 50 °C, resulting in a quantitative yield of B,B′,B″-triethyl-N,N′,N″-trimethylborazine. On the other hand, a complex prepared from (t-Bu)3P (4 equiv.) and [Rh(coe)2Cl]2 gave the best yield for hydroboration of terminal or internal alkenes.

Innovative reuse process of rice husks (RH), being one of the representative agricultural wastes, has been developed to fabricate magnesium composites by solid-state reaction to form magnesium silicide (Mg2Si) reinforcements, having high hardness and Young’s modulus. From a view point of the biomass energy, rice husks, including about 70 mass% organics, could be effectively used as environmentally benign fuels to supply electric power or biomass ethanol. Considering that the most of the rice husk wastes after absorbing organics is SiO2, the solidstate synthesis of Mg2Si compounds by reaction of SiO2 with magnesium was suggested in this study. First of all, the effect of the acid washing treatment to remove organics of rice husks on the crystallization of amorphous SiO2 was evaluated by TG-DTA and XRD analysis. The carbon content of 0.05% in the wastes was drastically reduced by using acid-washed rice husks, compared to that of non acid-washed ones (0.19%). When employing the wastes with and without the acid washing treatment, the crystallization temperature is about 1273 and 1073 K, respectively. The latter showed the lower crystallization temperature because the reaction of the alkaline contents, such as K, P, and Ca, with SiO2 during heating caused to decrease the SiO2 melting point. Rice husk wastes burned at 1273 K after the acid treatment was mixed with AZ31 magnesium alloy powder to fabricate the magnesium composites including Mg2Si dispersoids. Microscope observation and XRD analysis indicated that the amorphous SiO2 included the wastes was more effective to promote Mg2Si formation.

This study evaluated the clinical use of serum metabolomics to discriminate malignant cancers including pancreatic cancer (PC) from malignant diseases, such as biliary tract cancer (BTC), intraductal papillary mucinous carcinoma (IPMC), and various benign pancreaticobiliary diseases. Capillary electrophoresismass spectrometry was used to analyze charged metabolites. We repeatedly analyzed serum samples (n = 41) of different storage durations to identify metabolites showing high quantitative reproducibility, and subsequently analyzed all samples (n = 140). Overall, 189 metabolites were quantified and 66 metabolites had a 20% coefficient of variation and, of these, 24 metabolites showed significant differences among control, benign, and malignant groups (p < 0.05; Steel–Dwass test). Four multiple logistic regression models (MLR) were developed and one MLR model clearly discriminated all disease patients from healthy controls with an area under receiver operating characteristic curve (AUC) of 0.970 (95% confidential interval (CI), 0.946–0.994, p < 0.0001). Another model to discriminate PC from BTC and IPMC yielded AUC = 0.831 (95% CI, 0.650–1.01, p = 0.0020) with higher accuracy compared with tumor markers including carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), pancreatic cancer-associated antigen (DUPAN2) and s-pancreas-1 antigen (SPAN1). Changes in metabolomic profiles might be used to screen for malignant cancers as well as to differentiate between PC and other malignant diseases.

The mechanical behavior of the non-aged and the aged Al–Mg–Si alloy composites reinforced with CNTs was evaluated with tensile test and Vickers hardness test. The composites showed higher mechanical strength than the pristine Al alloy before the aging, although exhibiting lower mechanical strength after the aging. The aging treatment was ineffective to strengthen the Al–Mg–Si alloy composites reinforced with CNTs. EDS elemental mapping clarified the Mg and O concentration around CNTs. The reduction of Al oxide species formed around CNTs facilitated the Mg concentration. Due to the Mg consumption around CNTs, Mg elements in Al matrix decreased, and resulted in the incomplete matrix strengthening after the aging.

Endoscopic ultrasonography (EUS)-guided transgastric and transduodenal drainage of a pancreatic pseudocyst (PP) has become a standard and safe procedure for nonsurgical treatment. However, there are only four reports on transjejunal drainage of PP in a patient with or without altered anatomy. Herein, we report a case of EUS-guided transjejunal PP drainage in a patient with previous Roux-en-Y reconstruction. A 58-year-old man, who had previously undergone total gastrectomy with Roux-en-Y, was admitted to another hospital because of fever, abdominal pain, nausea and vomiting. Computed tomography showed a 22 cm PP. Then, EUS-guided transjejunal PP drainage was carried out. Twenty-three days after the procedure and 3 days after the patient started eating, the hematemesis was seen. Emergency endoscopy showed bleeding around a transjejunal fistula. A 6-Fr nasocystic catheter was placed into the cyst again for lavage and hemostasis as tamponade. After 1 more month, a computed tomography scan showed complete resolution of the PP with the stent still in place.

Wire-guided cannulation has become a common biliary cannulation technique worldwide. Different guidewires with various tip shapes and materials have been reportedly used for wire-guided cannulation. However, there are apparently no studies reporting changes in the biliary cannulation rate according to the type of guidewire used. We evaluated the effectiveness of the J-tip guidewire for biliary cannulation. We conducted a prospective, multicenter, controlled study involving patients with a native papilla who required biliary cannulation. We allocated the patients to the J-tip guidewire or angled-tip guidewire groups (groups J and A, respectively). If biliary cannulation was not achieved within 10 min, the GW was changed and cannulation was continued. Groups J and A consisted of 66 and 65 enrolled patients, respectively. The biliary cannulation rate with a single guidewire for the first 10 min was 84.8 % (56/66) for group J and 80.0 % (52/65) for group A. The final success rate for biliary cannulation was 100 % in both groups. The mean times necessary for biliary cannulation were 285.8 and 267.6 s in group J and group A, respectively. The incidence rates of complications (i.e., all mild pancreatitis) were 3.0 % (2/66) and 6.2 % (4/65) in group J and group A, respectively. The mean amylase concentrations were 168.0 and 297.7 IU/L in group J and group A, respectively. There were no significant differences in any results between both groups. The biliary cannulation rate of the J-tip guidewire was not significantly different from those of standard guidewires.

Background There are currently no dedicated plastic stents for EUS-guided hepaticogastrostomy (EUS-HGS). Objective We prospectively evaluated the feasibility and the technical and functional success rates of our newly designed plastic stent for EUS-HGS. Design Prospective preliminary feasibility study. Setting A tertiary-care referral center. Patients Twenty-three consecutive patients were treated. The reasons for requiring EUS-HGS were periampullary tumor invasion (n = 9), altered anatomy (n = 7), failed duodenal intubation (n = 3), and previous ERCP failure (n = 4). Interventions An 8F single-pigtail plastic stent with 4 flanges was placed for EUS-HGS. Main Outcome Measurements Technical success, clinical success, and adverse events according to the American Society for Gastrointestinal Endoscopy lexicon. Results All stents were successfully deployed without procedural adverse events (100% technical success rate). Bleeding from the punctured gastric wall occurred in 1 patient 3 days postoperatively. We exchanged the plastic stent for a fully covered self-expandable metal stent. A mild adverse event of self-limited abdominal pain occurred in 3 patients. Treatment success was achieved in all patients. The occlusion rate was 13.7% (3/22) during the median follow-up period (5.0 months, range 0.5-12.5 months). The median duration of stent patency was 4.0 months (range 0.5-9.0 months). There was no stent migration or dislocation during the follow-up period. Limitations Small number of patients and lack of a control group. Conclusions This newly designed single-pigtail plastic stent dedicated for EUS-HGS was technically feasible and can possibly be used for highly selected patients with advanced malignancy or benign stricture. (Trial Registration: http://www.umin.ac.jp/english/: UMIN000012993.)

To evaluate the safety and clinical application of high-intensity focused ultrasound (HIFU) therapy for unresectable pancreatic cancer (PC).Thirty PC patients (16 cases in stage III and 14 cases in stage IV) with visualized pancreatic tumors were admitted for HIFU therapy as an optional local therapy in addition to systemic chemotherapy or chemoradiotherapy. Informed consent was obtained. This study began at the end of 2008 and was approved by the ethics committee of our hospital [Institutional Review Board (IRB): 890]. The HIFU device used was the FEP-BY02 (Yuande Bio-Medical Engineering, Beijing, China).The mean tumor size after HIFU therapy changed to 30.9 ± 1.7 mm from 31.7 ± 1.7 mm at pre-therapy. There were no significant changes in tumor size, mean number of treatment sessions (2.7 ± 0.1 mm), or mean total treatment time (2.4 ± 0.1 h). The rate of symptom relief effect was 66.7%. The effectiveness of primary lesion treatment was as follows: complete response, 0; partial response, 4; stable disease, 22; progressive disease, 4. Treatment after HIFU therapy included 2 operations, 24 chemotherapy treatments, and 4 best supportive care treatments. Adverse events occurred in 10% of cases, namely pseudocyst formation in 2 cases and mild pancreatitis development in 1. However, no severe adverse events occurred in this study.We suggest that HIFU therapy is safe and has the potential to be a new method of combination therapy for PC.

Endoscopic sphincterotomy (ES) combined with large balloon dilation (ESLBD) can be useful for extracting large and multiple bile duct stones. Although there are many studies on the feasibility and short-term outcome, there are few reports about mid- to long-term outcome after ESLBD. The aim of our study is to prospectively evaluate the mid-term outcome of ESLBD.One hundred eighty-three patients who underwent ESLBD between November 2006 and May 2012 were included. The patients were followed up periodically after the procedure until April 2013. Papillary dilation was performed at the time of initial ES or prior ES. Early and late adverse events and stone recurrence were evaluated in this study.The patients' mean age was 76.6 ± 10.7 years. Surgically altered anatomy was present: Billroth I gastrectomy (2), Billroth II gastrectomy (13), and gastrectomy with Roux-en Y reconstruction (18). Seventy-eight (42.6%) patients had periampullary diverticulum. Prior ES had been performed in 40 (21.9%) patients. The mean follow-up period was 43.5 ± 19.7 months (range 11-78). Eight (4.4%) patients had stone recurrence. There was rare stone recurrence after initial ESLBD treatment and native gastrointestinal anatomy. Univariate and multivariate analyses showed that prior ES and previous history of stone recurrence were predictive of stone recurrence (P 0.001).At mid-term outcome, ESLBD is associated with a low rate of recurrent bile duct stones, although long-term follow up is needed.

Background There are currently no prospective, controlled trials of endoscopic transpapillary gallbladder drainage in patients with acute cholecystitis. Objective We evaluated the technical success rate and efficacy of endoscopic transpapillary gallbladder drainage by using either endoscopic nasogallbladder drainage (ENGBD) or endoscopic gallbladder stenting (EGBS) for patients with acute cholecystitis. Design Randomized, controlled study. Setting Tertiary-care referral centers. Patients Seventy-three consecutive patients with acute cholecystitis were randomized. Interventions ENGBD by using a 5F or 7F tube (n = 37) or EGBS (n = 36) by using a 7F stent. Main Outcome and Measurements Technical success, clinical success, adverse events, and procedure-related pain score. Results The overall technical success rates in the ENGBD and EGBS groups were 91.9% and 86.1%, respectively ( P > .05). The mean procedure times of ENGBD and EGBS were 20.3 ± 12.1 and 22.2 ± 14.5 minutes, respectively ( P > .05). The overall clinical success rates by per protocol analysis were 94.1% and 90.3% in the ENGBD and EGBS groups, respectively, whereas the rates by intention-to-treat analysis were 86.5% and 77.8%, respectively ( P > .05). Moderate adverse events were observed in the ENGBD (n = 2) and EGBS (n = 1) groups. The mean visual analog score of postprocedure pain in the ENGBD group was significantly higher than that in the EGBS group (1.3 ± 1.1 vs 0.4 ± 0.8, respectively; P Limitations Small sample size and the participation of multiple endoscopists who may have different levels of experience in endoscopic transpapillary gallbladder drainage. Conclusions Both ENGBD and EGBS appear to be suitable for the treatment of acute cholecystitis in patients who are poor candidates for emergency cholecystectomy. (Clinical trial registration number: UMIN000012316.)

Magnesium is easy to be corroded because it has small standard electrode potential (SEP). In magnesium alloys, the corrosion resistance of dispersoids hasn’t yet evaluated quantitatively as the SEP of dispersoids wasn’t almost investigated. This study surveyed the surface potential difference (SPD) between α-Mg in AZ91D magnesium alloy and the dispersoids in that alloy by using Scanning Kelvin Probe Force Microscope (SKPFM). The corrosion resistance was evaluated and correlated with SPD, where this measured SPD represents the difference of work function between α-Mg and the dispersoid. At this experiment, it was obtained that the difference of SEP generally increases as the SPD increases. The good correlation between difference of SEP and SPD was obtained. The SPD between α-Mg and Mg17Al12 or Al6Mn in AZ91D Mg alloy is measured. In addition, in order to obtain the reference of SPD, the area of α-Mg only and the interface area between Fe and α-Mg were respectively scanned. The result shows that Mg17Al12 has small SPD to α-Mg and that the SPD between Mg17Al12 and α-Mg is mostly the same as that in α-Mg. Therefore, Mg17Al12 is considered of no effect on corrosion. On the other hand, Al6Mn degrades corrosion resistance because the SPD between Al6Mn and α-Mg is as large as that between Fe and α-Mg.

Recently, several endoscopists have described the usefulness of the endoscopic ultrasonography (EUS)-guided, single transluminal gateway technique (SGT) using transmural placement of single or multiple plastic stents or metal stents for a pancreatic pseudocyst (PC) and walled-off necrosis (WON). Moreover, the uses of the multiple transluminal gateway technique (MTGT) and single transluminal gateway transcystic multiple drainages (SGTMD) for complicated pancreatic walled-off necrosis have recently been reported. The aim of this study is to evaluate retrospectively the feasibility and efficacy of endotherapy for the treatment of complicated PC and WON cases.Eighty-nine patients with a PC (n = 14) and WON (n = 75) were treated under EUS guidance.In a total of 89 cases using SGT in combination with MTGT or SGTMD, the present study showed a technical success rate of 100 %, a final clinical success rate of 97.8 %, an adverse event during procedure rate of 0 %, an early adverse event rate of 12.4 %, and a mortality rate of 2.2 %.Even complicated WON cases can be treated using combination endotherapies, although a surgical approach as well as a percutaneous approach should be considered in the cases refractory to endoscopic therapies.

Pancreatic duct stones are a common complication of chronic pancreatitis. We describe successful endoscopic removal of a large pancreatic duct stone using large-balloon dilation in combination with pancreatic sphincterotomy. A 63-year-old woman was admitted for endoscopic treatment of acute on chronic pancreatitis with diabetes and epigastric pain with liver dysfunction due to a large impacted stone within the distal main pancreatic duct. Endoscopic pancreatic sphincterotomy was carried out using a wire-guided pull-type sphincterotome. Although we could carry out a relatively large incision, the stone could not be extracted. We therefore carried out papillary dilation using a large balloon (diameter 12 to 15 mm) to make room alongside the stone. A 10 × 20-mm white pancreatic duct stone was extracted during the process of pulling a dilating balloon into the working channel of the endoscope. Eventually, the second stone was removed without any procedure-related complication.

One of the chitinase genes of Alteromonas sp. strain O-7, the chitinase C-encoding gene ( chiC ), was cloned, and the nucleotide sequence was determined. An open reading frame coded for a protein of 430 amino acids with a predicted molecular mass of 46,680 Da. Alignment of the deduced amino acid sequence demonstrated that ChiC contained three functional domains, the N-terminal domain, a fibronectin type III-like domain, and a catalytic domain. The N-terminal domain (59 amino acids) was similar to that found in the C-terminal extension of ChiA (50 amino acids) of this strain and furthermore showed significant sequence homology to the regions found in several chitinases and cellulases. Thus, to evaluate the role of the domain, we constructed the hybrid gene that directs the synthesis of the fusion protein with glutathione S -transferase activity. Both the fusion protein and the N-terminal domain itself bound to chitin, indicating that the N-terminal domain of ChiC constitutes an independent chitin-binding domain.

To evaluate the usefulness of real-time virtual sonography (RVS) in biliary and pancreatic diseases.This study included 15 patients with biliary and pancreatic diseases. RVS can be used to observe an ultrasound image in real time by merging the ultrasound image with a multiplanar reconstruction computed tomography (CT) image, using pre-scanned CT volume data. The ultrasound used was EUB-8500 with a convex probe EUP-C514. The RVS images were evaluated based on 3 levels, namely, excellent, good and poor, by the displacement in position.By combining the objectivity of CT with free scanning using RVS, it was possible to easily interpret the relationship between lesions and the surrounding organs as well as the position of vascular structures. The resulting evaluation levels of the RVS images were 12 excellent (pancreatic cancer, bile duct cancer, cholecystolithiasis and cholangiocellular carcinoma) and 3 good (pancreatic cancer and gallbladder cancer). Compared with conventional B-mode ultrasonography and CT, RVS images achieved a rate of 80% superior visualization and 20% better visualization.RVS has potential usefulness in objective visualization and diagnosis in the field of biliary and pancreatic diseases.

Pancreatic duct guidewire placement (P-GW) techniques include both the injection cannulation technique with a contrast medium and wire-guided cannulation without contrast injection for selective biliary cannulation; the latter is the so-called "double-guidewire technique" (D-GW). The aim of this study was to compare the outcomes between P-GW and D-GW for biliary cannulation.The procedures for biliary cannulation with a naïve papilla were performed in a total of 363 cases. We divided the patients chronologically, according to the time period during which the procedures were performed, into two groups: group A, P-GW performed from March 2008 to June 2009; and group B, D-GW performed from July 2009 to December 2010. The success rates and complication rates were evaluated in each group.Biliary cannulation was successful in 31 (81.6%) patients in the P-GW group and 34 patients (82.9%) in the D-GW group. The onsets of postendoscopic retrograde cholangiopancreatography pancreatitis (PEP) occurred in the P-GW and D-GW groups were four (10.5%) and three (7.3%) patients, respectively, and all were mild cases (P = 0.616). The frequency of hyperamylasemia and the serum amylase level tended to be lower in the D-GW group than in the P-GW group (P = 0.213). There was a statistically significant difference on the onsets of PEP in the GW and non-GW groups (P = 0.04, 8.9% and 1.1%, respectively).Both the D-GW and P-GW techniques were equally effective for difficult biliary cannulation. Furthermore, the complication rates, including PEP, were similar in both techniques. A prospective randomized trial is warranted.

Background. Recent diagnostic imaging tests contribute to improving the diagnosis of pancreatobiliary cancers. However, it is not practical to perform these tests for all patients as screening. Thus, less-invasive and simple screening tests are still required. A method to detect the IgG antibody induced in serum against the p53 protein accumulating due to p53 gene mutation, as a biomarker, was developed around 1990.Method. 35 patients with pancreatic cancer, 12 patients with biliary tract cancer, and 31 patients with benign pancreatobiliary diseases were entered into this study. Measurement of serum anti-p53 antibody was conducted in all patients. In addition, the rate of p53 protein overexpression was examined in those cases that could be examined pathologically.Result. Among all patients in the pancreatic cancer and biliary tract cancer groups, there was no patient with serum anti-p53 antibody positive value that exceeded the standard value. The rate of p53 protein overexpression was 48.0% in the patients with pancreatobiliary cancers and 0% in the benign pancreatobiliary diseases group.Conclusion. Serum anti-p53 antibody measurement does not contribute to the diagnosis of pancreatobiliary cancers. Instead, traditional p53 immunostaining still appears to be valuable in combination with standard procedures.

Various approaches to biliary drainage, especially endoscopic ultrasonography (EUS)-guided drainage, have become commonly used as an alternative method for biliary decompression for malignant biliary obstruction. Occasionally, however, duodenal obstruction and non-dilated intrahepatic bile duct impede conventional EUS-guided biliary drainage. Herein, we describe a case of cholecystogastrostomy successfully carried out using a newly developed fully covered lumen-apposing self-expandable metallic stent (SEMS). EUS-guided cholecystogastrostomy should be considered an option for biliary decompression. This is a particularly ideal alternative if the patient has duodenal strictures with or without a duodenal metal stent and a non-dilated intrahepatic bile duct, which suggests the impossibility of choledochoduodenostomy and hepaticogastrostomy. Furthermore, the newly developed fully covered lumen-apposing SEMS seems ideal for EUS-guided cholecystoenterostomy.

Background/aims Recently, controllable biopsy forceps (MTW, D°sseldorf, Germany) have been developed. This biopsy forceps were 90° adjustable. In the present study, the feasibility and efficacy of the controllable biopsy forceps were compared with those of conventional biopsy forceps in patients with biliary tract disease. Methodology A total of 27 patients with biliary tract lesions were enrolled. We evaluated the procedure time, the sample tissue size and the diagnostic accuracy. In addition, the physicians performing the procedure rated their impressions about operability into 3 classes: excellent, fair and poor. Results The sensitivity in distinguishing benign from malignant lesions was 71.4% (15/21) for the 90° adjustable type and 66.7% (14/21) for the conventional type. The accuracy rate was 77.8% (21/27) for the 90° adjustable type and 74.0% (20/27) for the conventional type. In terms of operability as rated by each physician, the 'excellent' rate was given more frequently to the 90° adjustable type 25.9% than for the conventional type 11.1% (p=0.047). Conclusions This preliminary study showed that controllable biopsy forceps compared to conventional type biopsy forceps, despite a larger diameter, enables biopsy in a similar procedure time and its ease of use was rated better.

To evaluate the efficacy and safety of endoscopic removal and trimming of self-expandable metallic stents (SEMS).All SEMS had been placed for distal biliary strictures. Twenty-seven endoscopic procedures were performed in 19 patients in whom SEMS (one uncovered and 18 covered) removal had been attempted, and 8 patients in whom stent trimming using argon plasma coagulation (APC) had been attempted at Tokyo Medical University Hospital. The APC settings were: voltage 60-80 W and gas flow at 1.5 L/min.The mean stent indwelling period for all patients in whom stent removal had been attempted was 113.7 ± 77.6 d (range, 8-280 d). Of the 19 patients in whom removal of the SEMS had been attempted, the procedure was successful in 14 (73.7%) without procedure-related adverse events. The indwelling period in the stent removable group was shorter than that in the unremovable group (94.9 ± 71.5 d vs 166.2 ± 76.2 d, P = 0.08). Stent trimming was successful for all patients with one minor adverse event consisting of self-limited hemorrhage. Trimming time ranged from 11 to 16 min.Although further investigations on larger numbers of cases are necessary to accumulate evidence, the present data suggested that stent removal and stent trimming is feasible and effective for stent-related complications.

Endoscopic ultrasonography (EUS)-guided transgastric and transduodenal drainage of a pancreatic pseudocyst (PP) has become a standard and safe procedure for nonsurgical treatment. However, there are only four reports on transjejunal drainage of PP in a patient with or without altered anatomy. Herein, we report a case of EUS-guided transjejunal PP drainage in a patient with previous Roux-en-Y reconstruction. A 58-year-old man, who had previously undergone total gastrectomy with Roux-en-Y, was admitted to another hospital because of fever, abdominal pain, nausea and vomiting. Computed tomography showed a 22 cm PP. Then, EUS-guided transjejunal PP drainage was carried out. Twenty-three days after the procedure and 3 days after the patient started eating, the hematemesis was seen. Emergency endoscopy showed bleeding around a transjejunal fistula. A 6-Fr nasocystic catheter was placed into the cyst again for lavage and hemostasis as tamponade. After 1 more month, a computed tomography scan showed complete resolution of the PP with the stent still in place.

EUS-guided pancreatic duct (PD) stent placement is always challenging. Apart from EUS-guided biliary drainage, it may be more difficult to dilate the needle tract unless a cautery dilator is used because penetration of the parenchyma of the pancreas by the dilation catheter alone is an arduous task. Herein, we describe a successful case in which a Soehendra stent retrieval device (SSD; Cook Endoscopy, Winston-Salem, NC, USA) was very effective in dilating the needle tract without a cautery dilator in a patient who had undergone a Whipple resection. A 68-year-old man underwent a Whipple resection 4 years before the procedure and had recurrent pancreatitis. Therefore, we performed EUS-guided pancreatic duct (PD) stent placement (Video, available online at www.giejournal.org). A 22-gauge needle was punctured into the PD (1.5 mm in diameter), and a 0.018-inch stiff guidewire was advanced into the jejunum. Next, we used a 4F tapered catheter to dilate the needle tract. However, the catheter did not advance into the PD. Therefore, we used an SSD to dilate the tract. Finally, the SSD was advanced into the PD (Fig. 1), and a transgastric 7F PD stent was placed across the pancreatojejunostomy after both the needle tract and the pancreatojejunostomy site were dilated by using a 4-mm dilating balloon, without any adverse events. After the stent placement, the patient had no symptoms until 3 months after the procedure when we exchanged the stent with a new stent, as scheduled. At that time

Pancreatic duct stones are a common complication of chronic pancreatitis. We describe successful endoscopic removal of a large pancreatic duct stone using large-balloon dilation in combination with pancreatic sphincterotomy. A 63-year-old woman was admitted for endoscopic treatment of acute on chronic pancreatitis with diabetes and epigastric pain with liver dysfunction due to a large impacted stone within the distal main pancreatic duct. Endoscopic pancreatic sphincterotomy was carried out using a wire-guided pull-type sphincterotome. Although we could carry out a relatively large incision, the stone could not be extracted. We therefore carried out papillary dilation using a large balloon (diameter 12 to 15 mm) to make room alongside the stone. A 10 × 20-mm white pancreatic duct stone was extracted during the process of pulling a dilating balloon into the working channel of the endoscope. Eventually, the second stone was removed without any procedure-related complication.