Search

Gear skiving is a state-of-the-art technique for machining internal gears with high efficiency. Numerical simulation method being able to analyze the eccentricity error e of cutter is critical to the understanding on the formation of surface roughness in skiving process. In this work, we proposed a novel Z-map-based numerical model to calculate the surface of gear flanks with eccentricity errors up to 9 μm. Correlation between eccentricity error and gear flank profile was clarified by numerical simulation and supported by experimental verification. The results show that the eccentricity error imposed a low-frequency motion during the generation of scallop height, leading to a surface roughness with a maximal error about four times that of the theoretical roughness. The e-induced scallop height became the majority factor account for variation of surface roughness when e exceeds 1.4 and 2.3 μm for feed rates of 0.4 and 0.8 mm/rev, respectively. The experimental result further supported the capability of proposed simulation model in providing detail surface features of gear flanks in skiving process.

A versatile photocatalyst-excimer-lamp hybrid unit for both air- and water-purification at practical scale was investigated. The unit consisted of a xenon filled quartz tube (20 mm i.d. × 300 mm length) and TiO2 nanoparticles-modified Ti-mesh sheet (TMiP™). Emission at 172 nm from a xenon excimer ( Xe 2 ∗ ) was able to produce reactive species by direct photolysis of water or air. At the same time, the emission was able to excite TiO2 on TMiP surface. Therefore, the unit decomposes organic contaminants by synergy of photocatalysis and photolysis. Air- and water-purification efficiency of the unit was examined by high concentration of acetaldehyde and phenol decomposition test, respectively. The disinfection activity of the units for waterborne pathogens was also investigated. For comparison, the purification units using excimer-lamp alone or UV lamps with TMiP and/or ozone treatment were evaluated in the same methods. The photocatalyst-excimer-lamp hybrid unit was able to decompose acetaldehyde and phenol effectively, compared with the other units. On the other hand, disinfection activity of the unit for waterborne pathogens was strongly affected by the kind of the waterborne pathogens. The difference of efficiency between organic pollutants and waterborne pathogens by the unit may be due to the molecular or bacterial size and the surface composition of bacteria and viruses, critical wavelength for disinfection, and the permeation ability of the outer wall of bacterial cells or virus particles for reactive species. Taken together, the photocatalyst-excimer-lamp hybrid unit has wide potentials for environmental purification by the synergy of photocatalysis and photolysis. These results would be attractive to develop a practical environmental purification system such as sewage water treatment.

O,N,O-tridentate ligands 2-H2 based on a 2,6-substituted pyridine structure and their dichlorotitanium complexes 3 were synthesized and structurally characterized. The complexes have five-coordinated, trigonal bipyramidal structure, in which one chlorine atom was located at trans-position to the nitrogen atom of the pyridine ring and the other was at cis-position. NMR spectroscopy indicated their fluxional structure in solution. The complexes showed low to modest catalytic activity for ethylene polymerization in the presence of methylaluminoxane (MAO) as a co-catalyst.

Background It is often difficult to insert a long intestinal tube in the small bowel of patients with bowel obstruction, and it often results in long procedure time and severe patient distress. Objective To assess the usefulness of the ropeway method by using a guidewire placed with the assistance of transnasal ultrathin endoscopy in long-tube insertion for patients with bowel obstruction. Design Prospective, randomized, controlled, single-center study. Patients and Interventions Thirty-four consecutive patients with bowel obstruction requiring decompression participated in the study and were randomized to the insertion of a long tube with the ropeway method (ILTR) group (ie, insertion along an endoscopically placed guidewire that was passed through only the distal 4 cm of the tube) or insertion by a conventional method group (C group). Main Outcome Measurements The time required for the procedure (main), success rate, x-ray exposure time, and intensity of patient distress measured with a visual analog scale of 1 to 5 (better to worse). Results The mean (± standard deviation) duration of the procedure in the successful cases in the ILTR group and the C group was 16.1 ± 5.6 minutes and 26.4 ± 13.8 minutes, respectively ( P = .010). The success rate was 100% in the ILTR group and 88% in the C group ( P = .48). The mean (± standard deviation) x-ray exposure time and intensity of patient distress were, respectively, 16.4 ± 8.7 minutes and 33.2 ± 12.3 minutes ( P P = .016). Limitations Single-center study and small sample size to evaluate overall safety. Conclusions Long-tube insertion for bowel obstruction with the ropeway method facilitated by transnasal ultrathin endoscopy was superior to conventional fluoroscopic placement with regard to overall procedure success, time required, and patient comfort.

The complete nucleotide sequence of dipeptidyl aminopeptidase IV (DAP IV) from Pseudomonas sp. WO24 was determined. Nucleotide sequence analysis revealed an open reading frame of 2238 bp, which was assigned to dap4 by N-terminal and internal amino acid sequences previously reported. The predicted amino acid sequence of DAP IV contains a serine protease Gly-X-Ser-X-Gly-Gly consensus motif and displays extensive homology to DAP IVs and the homologous proteins from eukaryotes and bacteria, belonging to the prolyl oligopeptidase family S9. In Pseudomonas sp. WO24, DAP IV is expressed as 82 and 84-kDa isoforms, having two Met, Met-1 and Met-12, in its N-terminal sequence. Met-1 of DAP IV was mutated to Gly and Met-12 was mutated to Ile, and we overexpressed the two mutated genes in Escherichia coli and obtained the recombinant 82 and 84-kDa proteins from the periplasm and the cytoplasm, respectively, suggesting that the 82 and 84-kDa isoforms are derived from the same gene and localize to different compartments in the cell. We developed purification steps for activting a large amount of 84-kDa isoform protein that will be useful for producing protein for crystallographic studies.

A 74-year-old woman complaining of abdominal pain and fever was referred to our department. Her levels of liver enzymes and serum amylase were within normal ranges. CA19-9 and gastrin were elevated: 121.1 U/mL (normal 37.0 U/mL) and 1100 pg/mL (normal 201 pg/mL), respectively. MRCP demonstrated the pancreatic duct and bile tract to be normal. Magnetic resonance imaging revealed a small mass lesion in the pancreatic tail, showing an isointensity with T1-weighted imaging, a high intensity with T2-weighted imaging, and a remarkably high signal on diffusion-weighted imaging. CT showed a small mass lesion with a clear border and slight enhancement (Fig. 1). EUS revealed a low echoic mass 9 mm in diameter with a homogeneous internal structure in the pancreatic tail without abnormalities in the pancreatic and bile ducts (Fig. 2). Endoscopic retrograde pancreatography showed no stricture

Background: The prognosis of gallbladder carcinoma is dismal and relates to the depth of invasion as expressed by the T factor in TNM staging. We evaluated the utility of endoscopic ultrasound (EUS) in the diagnosis of the depth of invasion of gallbladder cancer. Methods: Thirty-nine patients who underwent both EUS and surgery were included in this study. The EUS images were classified according to the relation between tumor echo pattern and gallbladder-wall structure, and the resulting types were compared with depth of invasion as determined histologically. Based on the results, a set of diagnostic criteria is proposed. Results: The EUS images were classified into four categories. Type A is a pedunculated mass with a fine-nodular surface and intact neighboring wall. Type B is a broad-based mass with an irregular surface and intact outer hyperechoic layer of the adjacent wall. In type C, the outer hyperechoic layer is irregular due to a mass echo, whereas, in type D, the outer hyperechoic layer is disrupted by a mass echo. Each of the four categories of EUS images correlated well with the histologic depth of invasion. Conclusion: EUS is useful in the T staging of gallbladder cancer.

Background: The prevalence of biliopancreatic disorders is high in patients with periampullary diverticula. However, endoscopic retrograde cholangiopancreatography (ERCP) in patients with the papilla deep inside duodenal diverticula is difficult. Methods: Two patients were included in this study, each with the papilla deep inside a diverticulum and in whom an initial ERCP was unsuccessful. A biopsy forceps to pinch the duodenal mucosa distal to the papilla and pull the papilla out of the diverticulum and a cannula were inserted into the working channel of a duodenoscope together (the two-devices-in-one-channel method). With coordination of the two instruments, cannulation of the bile duct was attempted. Results: In both patients ERCP was successful using this procedure and no complications followed. Conclusions: The two-devices-in-one-channel method is useful when performing ERCP in patients with the papilla inside juxtapapillary diverticula.

pearance of the lesions, and their involvement of the mesenteric peritoneum. Perhaps Ogden, one of the first to recognize the pathology, in the study by Ogden et al. 12 described it best-"The gross appearance of the involved mesentary is at first confusing, but, once seen, the picture is not easily forgotten, and gross diagnosis is not difficult the second time." Biopsy, however, is necessary to rule out malignancy and to verify the diagnosis. As the bowel itself is not biopsied and the samples are taken under direct vision, there should be little risk of bowel perforation. A 3-mm lancet-shaped biopsy forceps is helpful in obtaining tangential biopsies. This further lowers the risk of perforation. Tru-Cut biopsy needles should not be used in this setting. Multiple biopsies of the affected area are required for accurate histologic diagnosis. This should not be difficult as the mesentary in retractile mesenteritis is typically rock hard and mobile. In the authors' experience, the root ofthe mesentary is accessible laparoscopically in greater than 90% of cases. To access this area, second puncture sites are required to retract and visually expose the appropriate areas. Access is further enhanced with use of a tilt table. The advantages of a laparoscopic diagnosis are multiple. The procedure is performed under local anesthesia, negating the potential problems of general anesthesia. The morbidity of exploratory laparotomy, including pain and adhesions, are avoided with lapa

Background: Some patients with autoimmune pancreatitis (AIP) suffer from disease progression during follow-up with no medication or from relapse after steroid treatment. Aim: To elucidate the proportion of patients with AIP showing disease progression or relapse and its predictive factors. Patients: Thirty-eight patients with AIP based on HISORt criteria from 1988 to 2010 were included in this study. Results: Of the 38 patients, 10 with histologically confirmed AIP after resection were followed-up conservatively with no medication. One patient (10%) developed relapse of AIP in the remnant pancreas. Of the other 28 patients, 14 were followed up without surgery or medication (median follow-up period: 1525 days), 2 of which (14.3%) showed disease progression and received steroid treatment. The remaining 14 patients received steroid treatment (initial dose: 30-60 mg/day) because of symptoms, and all of them achieved remission. In 7 of these 14 patients, steroid treatment was stopped (period to discontinuance of the treatment: 23-1366 days), and 4 of these 7 (57.1%) developed relapse (period to relapse: 19-737 days). The remaining 7 patients received maintenance treatment with low-dose steroid (period of maintenance treatment: 155-2749 days), 1 of which (14.3%) developed relapse after 265 days from initial steroid administration. Sex, age, diabetes mellitus (DM), icterus, serum IgG4 level, diffuse pancreatic swelling, other organ involvement (OOI), steroid treatment, and maintenance treatment with low-dose steroid were investigated with univariate analysis in 30 patients of AIP who had been followed up for more than 6 months to evaluate the predictive factors for disease progression or relapse, the results being as follows: male (p=0.623, OR: 1.1, 95%CI: 0.2-7.5), age less than 70 y.o. at onset (p=0.004), icterus (p=0.288, OR: 3.3, 95%CI: 0.3-32.3), DM (p=0.659, OR: 1.0, 95%CI: 0.2-5.0), serum IgG4 level >500 mg/dl (p=0.651, OR: 1.1, 95%CI: 0.28.1), diffuse pancreatic swelling (p=0.223, OR: 2.9, 95%CI: 0.5-16.4), OOI (p=0.541, OR: 1.4, 95%CI: 0.2-9.2), steroid treatment (p=0.195, OR: 2.9, 95%CI: 0.6-15.6) and maintenance treatment with low-dose steroid (p=0.480, OR: 2.1, 95%CI: 0.2-20.8). Multivariate analysis including age, diffuse pancreatic swelling and steroid treatment, which showed p

Su1438 Efficacy and Safety of a Newly Developed Fully Covered Biliary Metallic Stent in Comparison With the Partially Covered WallFlex Biliary RX Stent for Unresectable Malignant Biliary Stricture Takahisa Ogawa, Kei Ito, Naotaka Fujita, Yutaka Noda, Go Kobayashi, Takashi Obana, Jun Horaguchi, Shinsuke Koshita, Yoshihide Kanno Department of Gastroenterology, Sendai City Medical Center, Sendai, Japan Background and aim: Endoscopic self-expandable metallic stent (SEMS) placement is widely accepted as a palliative therapy in patients with unresectable malignant biliary stricture. Although a covered SEMS has been reported to have a longer stent patency than an uncovered SEMS, complications such as stent migration and kinking of the bile duct can occur after deployment. A newly developed fully covered biliary metallic stent (ZEOSTENT Covered (ZEO), Zeon Medical Inc., Tokyo, Japan) which has an uneven outer surface, a low shortening ratio, and a low axial force might reduce such complications. The aim of this study was to evaluate the efficacy and safety of this new covered biliary stent in comparison with the partially covered WallFlex Biliary RX Stent (Wall) (Boston Scientific, Co., Ltd., Natic, MA, USA). Patients and methods: Between March 2010 and November 2010, endoscopic placement of a ZEO was performed in 24 patients (mean age, 77 10 yrs; 10 males, 14 females) with unresectable malignant biliary stricture. Fifteen patients had pancreatic cancer, 4 had bile duct cancer, 2 had gallbladder cancer, 2 had ampullary cancer and 1 had lymph node metastases from other cancers. Main outcome measurements were success rate of the procedure, early complications, late complications, and stent patency. Early complications were defined as those which occurred within 3 days after stent placement. Such data were compared with those of 24 patients (mean age, 75 12 yrs; 13 males, 11 females) who had undergone endoscopic placement of a Wall between April 2009 and July 2010. Results: Mean follow-up duration of the ZEO group and the Wall group were 77 days and 124 days, respectively (P 0.024). Stent placement was successful and improvement of jaundice was obtained in all patients of both groups. ZEO and Wall were transpapillarily placed in 18 and 22 patients, respectively. Transduodenal and transgastric stent placement utilizing the endosonography-guided biliary drainage route was performed in 5 and 2 patients, respectively. Early complications occurred in 1 patient in the ZEO group (pancreatitis, 1) and in 4 in the Wall group (pancreatitis, 3; cholecystitis,1) (P 0.17). Late complications occurred in 5 patients of the ZEO group (stent occlusion, 4; stent migration, 1; cholecystitis, 1) and in 6 of the Wall group (stent occlusion, 1; stent migration, 2; cholecystitis, 3; cholangitis without stent occlusion, 1) (P 1.00). In 3 cases of the ZEO group, tumor ingrowth occurred due to breakage of the cover, whereas there were no such cases in the Wall group. Mean stent patency duration of the ZEO group and the Wall group were 243 days and 382 days, respectively (P 0.20). Conclusion: The short-term efficacy and safety of ZEO were comparable with those of Wall. However, improvement of the cover of the ZEO is indispensable for prevention of tumor ingrowth.

AIM: To evaluate the efficacy of the microscanner (MS) in diagnosing the depth of submucosal invasion in early colorectal cancer. PATIENTS: One hundred seventy-four patients with colorectal cancers including 80 protruding lesions (mucosal cancer (m) 41, submucosal cancer (sm) 39) and 94 superficial lesions (m, 41; sm, 52). METHODS: The diagnostic accuracy of depth of invasion in early colorectal cancer by MS was analyzed. The MS diagnosis was made based on the extent of a tumor echo into the third hyperechoic layer of the bowel wall which is considered to be the submucosa. Carcinomas which showed involvement of the submucosal layer were divided into two groups according to the histological degree of invasion: sm1, a group in which the depth of invasion was 1/3 of the submucosal layer or less; sm2-3, a group in which the depth of invasion of the submucosa was over 1/3. The MS diagnosis was compared with the histological diagnosis of the depth of invasion in each lesion. RESULTS: 1) Visualization of the lesion by MS was possible in 87% (152/174) of the lesions, i.e., 81% in protruding lesions and 92% in superficial lesions. 2) The accuracy of MS in diagnosing the depth of invasion in all lesions, in protruding lesions, and in superficial lesions was 93%, 88%, and 95%, respectively. 3) Diagnostic accuracy of MS as to the degree of submucosal invasion was 91% in m and sm1 cancer and 96% in sm2-3 cancer. CONCLUSIONS: MS is useful for the diagnosis of the depth of invasion in early colorectal cancers. Improvement of the accuracy in diagnosing protruding lesions is required.