Sulfur doped FeNC catalysts derived from Dual-Ligand zeolitic imidazolate framework for the oxygen reduction reaction.

Iron-nitrogen-carbon (FeNC) catalysts derived from zeolitic-imidazolate frameworks (ZIFs) are worldwide accepted to be the most promising candidates for the oxygen reduction reaction (ORR), but the insufficient stability, the low FeNx exposure and poor density restrict their ORR activity. Here, we demonstrate a strategy to synthesize FeNx sites embedded in a micro/mesoporous N, S co-doped graphitic carbon (FeNC/MUS) by tuning the ligand linkers via the addition of 2-undecylimidazole as a co-ligand in ZIF precursors, and optimizing the electronic structure of Fe center by an in-situ addition of thiourea molecules as sulfur (S) source. 2-undecylimidazole offered an open porous structure to incorporate more FeNx, while the S-doping increased the density of FeNx. Besides, 2-undeclyimidazole cooperatively with S-doping caused favorable changes into the catalyst structure, particularly improved the exposure and density of FeNx sites and doubled the Brunauer-Emmetter-Teller surface area to 1132 m2 g-1 contrasted to the pristine FeNC/M (544 m2 g-1). FeNC/MUS displayed an accelerated ORR activity with a higher half-wave potential of 0.86 V (vs. reversible hydrogen electrode (RHE)) than that of Pt/C (0.84 V) in addition of a longer durability with a 11 % of activity decay after 30000 s in alkaline media. This work offers a new insight to design optimal ZIFs precursor and a facile electron withdrawing S-doping strategy for efficient electrocatalysis.

Mechanical colon cleansing for screening colonoscopy: A randomized controlled trial.

OBJECTIVE: Effective screening colonoscopy depends on the quality of colon preparation. This study aimed to compare pulsed irrigation evacuation (PIE), polyethylene glycol (PEG) and sodium phosphate colon preparations. METHODS: Outpatients at a VA hospital were randomized using sealed envelopes. Preparations consisted of polyethylene glycol 4L, Fleet sodium phosphate 90 mL with four to six glasses water twice daily and 296 mL of magnesium citrate in the evening with PIE prior to colonoscopy. Colon cleansing was assessed blindly using a five-point scale: 0 (very poor) to 4 (excellent). RESULTS: Altogether 391 patients participated in the study (129 in the PEG group, 127 in the sodium phosphate and 135 in the PIE group), with a mean age of 62 years, of whom 75% were men. PIE and sodium phosphate were superior to PEG: median cleansing scored 4 (excellent) versus 3 with PEG (P < 0.01). Inadequate preparations were more common with PEG than PIE (18% vs 5%) (P < 0.01). Side-effects included vomiting: 37% in the sodium phosphate group versus 5% in the PEG and 2% in the PIE groups (P < 0.01). The three preparations were judged intolerable in ≤ 5%. CONCLUSIONS: PIE and sodium phosphate are superior to PEG for colon preparations. PIE is the preferred preparation for those at high risk of unsatisfactory preparations or with unsatisfactory traditional preparations.

Trends in endoscopic retrograde cholangiopancreatography in children within the United States, 2000-2009.

We investigated the volume of endoscopic retrograde cholangiopancreatographies (ERCPs) performed in hospitalized children in the United States using a nationwide healthcare administrative database for the years 2000 to 2009. A total of 22,153 cases of ERCP were identified: 6372 diagnostic and 17,314 therapeutic (1533 cases were recorded as undergoing both types during a single hospitalization). The number of ERCPs increased from 5337 to 6733 per year; diagnostic ERCPs decreased 43% and therapeutic increased 69% (significant decreasing trends for diagnostic and increasing for therapeutic ERCPs, P<0.001 for each analysis). Our results define a recent increase in the use of therapeutic ERCPs in hospitalized children.

Endoscopic ultrasound-guided fine-needle aspiration with on-site cytopathology versus core biopsy: a comparison of both techniques performed at the same endoscopic session.

BACKGROUND: Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) with bedside cytopathology is the gold standard for assessment of pancreatic, subepithelial, and other lesions in close proximity to the gastrointestinal tract, but it is time-consuming, has certain diagnostic limitations, and bedside cytopathology is not widely available. AIMS: The goal of this study is to compare the diagnostic yield of EUS-guided FNA with on-site cytopathology and EUS-guided core biopsy. METHODS: Twenty-six patients with gastrointestinal mass lesions requiring biopsy at a tertiary medical center were included in this retrospective analysis of a prospective cohort. Two core biopsies were taken using a 22 gauge needle followed by FNA guided by a bedside cytopathologist at the same endoscopic session. The diagnostic yield and test characteristics of EUS core biopsy and EUS FNA with bedside cytopathology were examined. RESULTS: The mean number of passes was 3.2 for FNA, and the mean procedure time was 39.4 minutes. The final diagnosis was malignant in 92.3 %. Sensitivity and specificity were 83 % and 100 %, respectively, for FNA, and 91.7 % and 100 %, respectively, for core biopsy. Diagnostic accuracy was 92.3 % for FNA and 84.6 % for core biopsy. The two approaches were in agreement in 88.4 % with a kappa statistic of 0.66 (95 % confidence interval 0.33 - 0.99). CONCLUSIONS: An approach using two passes with a core biopsy needle is comparable to the current gold standard of FNA with bedside cytopathology. The performance of two core biopsies is time-efficient and could represent a good alternative to FNA with bedside cytopathology.

Capsule endoscopy for screening for short-segment Barrett's esophagus.

BACKGROUND: The rise in the incidence of esophageal adenocarcinoma has led to the development of new methods to screen for the precursor lesion, Barrett's esophagus. AIM: To evaluate the potential role of esophageal capsule endoscopy in identifying the presence of short-segment Barrett's esophagus. METHODS: Patients with biopsy-proven short-segment Barrett's esophagus underwent esophageal capsule endoscopy. The images were reviewed by two expert observers with no knowledge of the purpose of the study. The data collected included transit time, quality of image, presence or absence of Z-line, Schatzki's ring, hiatal hernia, and Barrett's esophagus (long or short, definite or suspected). RESULTS: Twenty patients were studied; in 18, the capsule passed into the stomach. Barrett's esophagus was identified or suspected in eight cases (44%) by one observer and three (16%) by the second (P= 0.14). Although the Z-line was seen in the 18 cases that were qualified by both observers, there was an agreement in only six cases as to whether it was regular or irregular. Erosive gastroesophageal reflux disease (GERD) was scored as present in three and absent in six patients by both readers. Nonexisting feline esophagus, varices, and distal esophageal stricture were suspected in one patient each. CONCLUSIONS: Esophageal capsule endoscopy had a high interobserver variability and a low yield for short-segment Barrett's esophagus. Esophageal capsule endoscopy cannot be recommended for screening for short-segment Barrett's esophagus.

Approach to the patient who has suspected acute bacterial cholangitis.

Table 4 gives summary recommendations concerning the major decisions that are related to the diagnosis and management of suspected acute bacterial cholangitis. All of these decisions have to be made within the context of disease severity, degree of diagnostic uncertainty, and associated comorbidity. Although these recommendations are based on evidence, there are few randomized controlled trials. Antibiotics that cover gram negatives and anaerobes, along with fluid and electrolyte correction, frequently stabilize the patient. Imaging studies frequently confirm the diagnosis and identify the location and etiology of the obstruction. With or without a definitive diagnosis, ERCP or PTC can be done emergently to establish drainage to control sepsis. Although endoscopic and percutaneous drainage techniques have lower morbidity and mortality than does emergent surgical decompression, optimal management of this potentially life-threatening condition requires close cooperation between the gastroenterologist, radiologist, and surgeon.