In Situ Derived Hybrid Carbon Molecular Sieve Membranes with Tailored Ultramicroporosity for Efficient Gas Separation.

Fine control of ultramicroporosity (<7 Å) in carbon molecular sieve (CMS) membranes is highly desirable for challenging gas separation processes. Here, a versatile approach is proposed to fabricate hybrid CMS (HCMS) membranes with unique textural properties as well as tunable ultramicroporosity. The HCMS membranes are formed by pyrolysis of a polymer nanocomposite precursor containing metal-organic frameworks (MOFs) as a carbonizable nanoporous filler. The MOF-derived carbonaceous phase displays good compatibility with the polymer-derived carbon matrix due to the homogeneity of the two carbon phases, substantially enhancing the mechanical robustness of the resultant HCMS membranes. Detailed structural analyses reveal that the in situ pyrolysis of embedded MOFs induces more densified and interconnected carbon structures in HCMS membranes compared to those in conventional CMS membranes, leading to bimodal and narrow pore size distributions in the ultramicroporous region. Eventually, the HCMS membranes exhibit far superior gas separation performances with a strong size-sieving ability than the conventional polymers and CMS membranes, especially for closely sized gas pairs (Δd < 0.5 Å) including CO2 /CH4 and C3 H6 /C3 H8 separations. More importantly, the developed HCMS material is successfully prepared into a thin-film composite (TFC) membrane (≈1 µm), demonstrating its practical feasibility for use in industrial mixed-gas operation conditions.

Defect Engineering in Metal-Organic Frameworks Towards Advanced Mixed Matrix Membranes for Efficient Propylene/Propane Separation.

Highly permselective and durable membrane materials have been sought for energy-efficient C3 H6 /C3 H8 separation. Mixed-matrix membranes (MMMs) comprising a polymer matrix and metal-organic frameworks (MOFs) are promising candidates for this application; however, rational matching of filler-matrix is challenging and their separation performances need to be further improved. Here, we propose a novel strategy of "defect engineering" in MOFs as an additional degree of freedom to design advanced MMMs. MMMs incorporated with defect-engineered MOFs exhibit exceptionally high C3 H6 permeability and maintained C3 H6 /C3 H8 selectivity, especially with enhanced stability under industrial mixed-gas conditions. The gas transport, sorption, and material characterizations reveal that the defect sites in MOFs provide the resulting MMMs with not only ultrafast diffusion pathways but also favorable C3 H6 sorption by forming complexation with unsaturated open metal sites, confirmed by in situ FT-IR studies. Most importantly, the concept is also valid for different polymer matrices and gas pairs, demonstrating its versatile potential in other fields.

Visceral adiposity is associated with an increased risk of functional dyspepsia.

BACKGROUND: The relationship between visceral adiposity and the incidence of functional dyspepsia (FD) has not yet been studied. The purpose of the present study is to evaluate the association between visceral adiposity and the risk of FD. METHODS: This is a case-control study that compares the abdominal adipose tissue area between subjects with FD and control subjects without FD, who underwent abdomen computerized tomography (CT) for health examinations in a tertiary center. Retrospectively, a telephone survey was conducted to diagnose FD using the Rome III criteria. We measured various indices of obesity including body mass index (BMI), waist circumference (WC), visceral adipose tissue (VAT) area, subcutaneous adipose tissue (SAT) area and the VAT/SAT ratio in order to evaluate the association between FD and abdominal adiposity. KEY RESULTS: A total of 363 subjects were included in the present study. FD was diagnosed in 90 subjects (24.8%). In the univariate analysis, WC, VAT area, TAT area, VAT/SAT ratio, and the presence of erosive esophagitis were significantly higher in the FD group than in the non-FD group. In the multivariate analysis, a higher VAT area (odds ratio (OR), 3.76; 95% confidence interval (CI), 1.24-11.40; highest quartile vs lowest quartile, p = 0.019) and VAT/SAT ratio (OR, 2.35; 95% CI, 1.27-4.32; highest quartile vs lowest quartile, p = 0.006) were independently associated with a risk of FD. CONCLUSION AND INFERENCES: Visceral adiposity as measured by the VAT area and VAT/SAT ratio is associated with an increased risk of FD.

Visceral Obesity Is Associated with Gallbladder Polyps.

BACKGROUND/AIMS: Gallbladder polyps (GBP) are a common clinical finding and may possess malignant potential. We conducted this study to determine whether visceral obesity is a risk factor for GBP. METHODS: We retrospectively reviewed records of subjects who received both ultrasonography and computed tomography with measurements of the areas of visceral adipose tissue and total adipose tissue (TAT) on the same day as health checkups. RESULTS: Ninety-three of 1,615 subjects (5.8%) had GBP and were compared with 186 age- and sex-matched controls. VAT (odds ratio [OR], 2.941; 95% confidence interval [CI], 1.325 to 6.529; p=0.008 for the highest quartile vs. the lowest quartile) and TAT (OR, 3.568; 95% CI, 1.625 to 7.833; p=0.002 for the highest quartile vs. the lowest quartile) were independent risk factors together with hypertension (OR, 2.512; 95% CI, 1.381 to 4.569; p=0.003), diabetes mellitus (OR, 2.942; 95% CI, 1.061 to 8.158; p=0.038), hepatitis B virus positivity (OR, 3.548; 95% CI, 1.295 to 9.716; p=0.014), and a higher level of total cholesterol (OR, 2.232; 95% CI, 1.043 to 4.778; p=0.039 for. CONCLUSIONS: Visceral obesity measured by VAT and TAT was associated with GBP irrespective of body mass index or waist circumference.

Behavior of Small, Asymptomatic, Nonfunctioning Pancreatic Neuroendocrine Tumors (NF-PNETs).

Small nonfunctioning pancreatic neuroendocrine tumors (NF-PNETs) usually exhibit minimal or no growth over many years. However, there is a controversy regarding the optimal management of incidentally discovered, small NF-PNETs. This study aimed to gain insights into tumor behavior and potential strategies for clinical management.We retrospectively reviewed a total of 202 patients with a suspected PNET (size 2 cm or smaller) at Samsung Medical Center from January 1, 1995 to April 30, 2012. Among these patients, 72 patients were excluded and 145 patients were enrolled in our study. Patients were included if the size of the tumor was ≤2 cm without familial syndrome, radiographic evidence of local invasion or metastases.Among the 145 patients, 76 patients (52.4%) had pathologically confirmed PNETs. Eleven (14.5%) and 3 (3.9%) of these 76 patients were diagnosed with NET G2 and G3, respectively. PNETs measuring 1.5 cm or more in size had a higher probability of being classified as NET G2 or G3 compared with PNETs measuring <1.5 cm (P = 0.03). Older age (≥55 years) and a meaningful tumor growth (≥20% or ≥5 mm) were significantly associated with NET G2 or G3 (P < 0.05).Older age (≥55 years), larger tumor size (≥1.5 cm), and a meaningful tumor growth (≥20% or ≥5 mm) were associated with NET G2 or G3. Intensive follow-up could be an acceptable approach in small (especially <1.5 cm), asymptomatic, NF-PNETs.

Comparison of endoscopic retrograde cholangiopancreatography with papillary biopsy and endoscopic ultrasound-guided pancreatic biopsy in the diagnosis of autoimmune pancreatitis.

BACKGROUND: International consensus diagnostic criteria (ICDC) have been proposed for the diagnostic criteria and algorithm of autoimmune pancreatitis (AIP). Although endoscopy is important in the diagnosis of AIP, practical patterns of its usage vary considerably worldwide. This study aimed to compare endoscopic retrograde cholangiopancreatography (ERCP) with papillary biopsy and endoscopic ultrasound (EUS)-guided pancreatic biopsy for diagnosing AIP using ICDC. METHODS: We retrospectively reviewed and classified 165 Korean patients diagnosed by Korean criteria from June 2007 to October 2013. Among them, 61 patients underwent ERCP with duodenal papillary biopsy (group A) and 62 patients underwent EUS-guided pancreatic biopsy (group B). We analyzed the diagnostic criteria and levels of each criterion, and type of AIP before and after endoscopic procedures. RESULTS: ERCP with papillary biopsy increased the diagnostic sensitivity from 65.6% (40/61) to 95.1% (58/61) (P < 0.01). EUS-guided pancreatic biopsy increased the diagnostic sensitivity from 50.0% (27/62) to 88.7% (55/62) (P < 0.01). The increases of diagnostic sensitivity in two endoscopic methods were not different statistically. In diagnosing definite AIP, EUS-guided pancreatic biopsy was more useful than ERCP with papilla biopsy (sensitivity; 79.0% vs. 65.6%, P < 0.01). EUS-guided pancreatic biopsy was helpful to classify type 1 and type 2 AIP in some patients. Procedure-related complication (mild pancreatitis) developed in one patient (1.6%) in group A and two patients (3.2%) in group B. ERCP with papillary biopsy was less expensive than EUS-guided pancreatic biopsy. CONCLUSIONS: Both ERCP with papillary biopsy and EUS-guided pancreatic biopsy are safe and play important roles in diagnosing AIP according to the ICDC.

Degradation of multi-DNAPLs by a UV/persulphate/ethanol system with the additional injection of a base solution.

This study was conducted to investigate the inhibited influences on and solution to the degradation of four types of dense non-aqueous phase liquids (DNAPLs) (i.e. perchloroethylene [PCE], trichloroethylene [TCE], chloroform [CF], and carbon tetrachloride [CT]) all at the same instance in groundwater (GW). Degradations of DNAPLs in de-ionized water (DW) and GW were carried out by applying an ultraviolet radiation-activated persulphate (UV/PS) system. PCE and TCE were degraded by over 90% and CT was only degraded by 25% in both DW and GW. However, CF was degraded by over 90% in DW, while it was only degraded by 50% in GW. First of all, degradations with an inorganic anion (either Cl- or HCO3-) indicated that the lower degradation of CF in GW was caused by the existence of the chloride ion. Moreover, the low CF degradation in GW was overcome by the additional injection of a base solution (sodium hydroxide [NaOH]) into the UV/PS system. The results showed that PCE, TCE, and CF were degraded by over 90%, respectively, when a molar ratio of [base]0:[PS]0 was larger than 0.5:1, but CT was still not effectively degraded in the UV/PS system. To achieve effective CT degradation, UV/PS with the ethanol (EtOH) system was evaluated and it was found that it degraded CT over 90%. However, at this time, CF was not effectively degraded in the UV/PS/EtOH system. Finally, degradations of DNAPLs in the UV/PS/EtOH system with the additional injection of a base solution were conducted and it showed that multi-DNAPLs were degraded by over 90%, respectively, when the molar ratio of [PS]0:[EtOH]0:[base]0 was 1:1:3.

Role of SpyGlass peroral cholangioscopy in the evaluation of indeterminate biliary lesions.

BACKGROUND: Accurate diagnosis of indeterminate biliary lesions is essential for treatment planning. The currently available techniques have some limitations in evaluating indeterminate biliary lesions. SpyGlass single-operator peroral cholangioscopy system has been developed to overcome these limitations. AIM: The aim of this retrospective study was to evaluate the diagnostic accuracy of SpyGlass visual assessment and SpyBite biopsy in patients with indeterminate biliary lesions. METHODS: We conducted a retrospective analysis of data from 36 patients with indeterminate biliary strictures or filling defects who had inconclusive results on the cross-sectional imaging study from September 2010 to October 2013. Four patients were excluded because of the presence of a metastatic mass and an ampulla of Vater cancer. RESULTS: Thirty-two patients (19 men, mean age 63.7 years) with indeterminate biliary lesions underwent SpyGlass cholangioscopy. The cholangioscopy procedure with SpyGlass was technically successful in all of the cases except for one case because of the intraprocedural breakage of the SpyGlass optic probe (96.8%, 31/32). The biopsy specimens from nineteen patients were obtained using SpyBite forceps. The sensitivity, specificity, and overall accuracy of SpyGlass visual assessment and SpyBite biopsy for the diagnosis of malignancy were 100% (21/21) and 64.2% (9/14), 90% (9/10) and 100% (5/5), and 96.7% (30/31) and 73.6% (14/19), respectively. Procedure-related complications were noted in three cases; postsphincterotomy bleeding in one case and mild pancreatitis in two cases. CONCLUSIONS: SpyGlass cholangioscopy with SpyBite biopsy is highly accurate and safe for differentiating malignant lesions from benign lesions in patients with indeterminate biliary lesions.

Primary mucosa-associated lymphoid tissue lymphoma of the esophagus, manifesting as a submucosal tumor.

We report a case of primary mucosa-associated lymphoid tissue (MALT) lymphoma in the esophagus that manifested as a large submucosal tumor (SMT). Primary esophageal lymphoma is very rare, occurring in less than 1% of all patients with gastrointestinal lymphoma. Only a few cases of MALT lymphoma in the esophagus have been reported in the English literature. A 53-year-old man was referred to Dongguk University Ilsan Hospital (Goyang, Korea) in July 2012 for further evaluation and treatment of an esophageal SMT. Endoscopy showed a cylindrically elongated submucosal mass with normal overlying mucosa in the mid esophagus, 25-30 cm from the incisor teeth. He underwent surgery to confirm the diagnosis. Pathologic findings showed diffuse small atypical lymphoid cells which were stained with Bcl-2, CD20, but not with CD3, CD5, CD23, Bcl-6, or cyclin D1. These cells showed a positive monoclonal band for immunoglobulin heavy chain gene rearrangement. Based on the pathological, immunohistochemical, and molecular biological features, the esophageal mass was diagnosed as extranodal marginal zone B-cell lymphoma of the MALT type.

Vegetarianism as a protective factor for reflux esophagitis: a retrospective, cross-sectional study between Buddhist priests and general population.

BACKGROUND/AIMS: Several risk factors for reflux esophagitis, such as smoking, alcohol consumption, obesity, and metabolic syndrome, are recognized. But vegetarianism as a protective factor for reflux esophagitis has not been reported. The aim of this study is to elucidate the protective effect of vegetarianism for reflux esophagitis. METHODS: This is a cross-sectional study that compared the prevalence of reflux esophagitis of 148 Buddhist priests, who are obligatory vegetarians with that of age- and sex-matched controls who underwent health checkups in a health promotion center. RESULTS: The prevalence of reflux esophagitis was higher in the control group than in the Buddhist priest group (21.6 vs 12.2 %). Weight, body mass index, waist circumference, waist-to-hip ratio, and abdominal adipose tissue area were higher and high density lipoprotein (HDL) cholesterol and total cholesterol were lower in the Buddhist priest group. The prevalence of metabolic syndrome was higher in the Buddhist priest group than the control group (30.4 vs 17.6 %). In univariate analysis, male sex (odds ratio [OR] = 3.325; 95 % confidence interval [CI], 1.659-6.666), current smoking (OR = 3.37; 95 % CI, 1.439-7.881), alcohol consumption (OR = 2.75; 95 % CI, 1.375-5.481), waist circumference (OR = 1.99; 95 % CI, 1.062-3.739), negative for Helicobacter pylori IgG antibody (OR = 1.89; 95 % CI, 1.018-3.491) and non-vegetarianism (OR = 1.99; 95 % CI, 1.062-3.739) were associated with reflux esophagitis. According to multivariate analysis, male sex (OR = 3.44; 95 % CI, 1.698-6.970), non-vegetarianism (OR = 2.08; 95 % CI, 1.086-3.974) and negative H. pylori IgG antibody (OR = 1.96; 95 % CI, 1.039-3.712) were significantly associated with reflux esophagitis. CONCLUSIONS: A non-vegetarian diet is associated with reflux esophagitis.