Cesium Doping for Performance Improvement of Lead(II)-acetate-Based Perovskite Solar Cells.

Lead(II)-acetate (Pb(Ac)2) is a promising lead source for the preparation of organolead trihalide perovskite materials, which avoids the use of inconvenient anti-solvent treatment. In this study, we investigated the effect of cesium doping on the performance of Pb(Ac)2-based perovskite solar cells (PSCs). We demonstrate that the quality of the CH3NH3PbI3 perovskite film was improved with increased crystallinity and reduced pinholes by doping the perovskite with 5 mol% cesium. As a result, the power conversion efficiency (PCE) of the PSCs was improved from 14.1% to 15.57% (on average), which was mainly induced by the significant enhancements in short-circuit current density and fill factor. A PCE of 18.02% was achieved for the champion device of cesium-doped Pb(Ac)2-based PSCs with negligible hysteresis and a stable output. Our results indicate that cesium doping is an effective approach for improving the performance of Pb(Ac)2-based PSCs.

The effect of metformin on the recurrence of colorectal adenoma in diabetic patients with previous colorectal adenoma.

PURPOSE: Existing studies suggest that metformin lowers the risk and mortality of colorectal cancer. However, the effect of metformin on the suppression and prevention of colorectal adenomas is not clear. The aim of this study was to evaluate the effect of metformin on the recurrence of colorectal adenoma in diabetic patients with previous colorectal adenoma. METHODS: Among 423 diabetic patients who underwent surveillance colonoscopy after resection of colorectal adenoma between 2005 and 2011, 257 patients were retrospectively reviewed. The patients were divided into two groups: one group comprising 106 patients who took metformin and another group comprising 151 patients who did not take metformin. The clinical characteristics, colorectal adenoma recurrence, and valuable factors for adenoma recurrence were analyzed. RESULTS: At surveillance colonoscopy after colonoscopic polypectomy for adenoma, 38 patients (35.8%) exhibited colorectal adenoma among 106 patients who took metformin, compared with 85 patients (56.3%) with colorectal adenoma among 151 patients who did not take metformin (odds ratio 0.434, 95% confidence interval 0.260-0.723, P = 0.001). Multivariate Cox analysis showed that metformin was associated with decreased recurrence of colorectal adenoma (hazard ratio 0.572, 95% confidence interval 0.385-0.852, P = 0.006) in diabetic patients with previous colorectal adenoma. The cumulative probability of colorectal adenoma recurrence was significantly lower in the metformin group than in the non-metformin group (P = 0.001). CONCLUSION: Metformin use in diabetic patients with previous colorectal adenoma is associated with a lower risk of colorectal adenoma recurrence.

[A case of Dieulafoy lesion of the jejunum presented with massive hemorrhage].

The Dieulafoy lesion is a rare cause of severe gastrointestinal hemorrhage. Although it may occur anywhere in the gastrointestinal tract, the lesion is most commonly located in the stomach, and the small bowel is an extremely uncommon site. Since Dieulafoy lesion in the small bowel is difficult to access by endoscopy, it seems impossible to diagnose and treat by initial endoscopy unlike the lesions in stomach. We experienced a case of Dieulafoy lesion of jejunum with massive hemorrhage in 54-year-old male. Active jejunal bleeding was shown by computed tomography scan and mesenteric angiography. Partial resection of the jejunum was performed. Final pathologic finding revealed Dieulafoy lesion of the jejunum.

Transition zone defect associated with the response to proton pump inhibitor treatment in patients with globus sensation.

BACKGROUND AND AIM: Few data describing short-term proton pump inhibitor (PPI) treatment in patients with globus sensation exist. The aim of this study was to evaluate the use of high-resolution manometry (HRM) for predicting the response to PPI treatment in patients with globus sensation. METHOD: A total of 41 patients with globus sensation were treated with PPIs for 4 weeks and were classified as positive and negative responders. HRM topographical plots were analyzed for relevant manometric parameters. In addition, clinical and HRM data of 20 patients with typical gastroesophageal reflux disease (GERD) not presenting globus symptom were analyzed. RESULTS: Of the 41 patients, 19 (46%) were clinically diagnosed with GERD. The proportion of patients with favorable symptomatic improvement was higher in patients with GERD than in those without reflux (P=0.046). Positive and negative responders to PPI treatment did not differ in upper esophageal sphincter and proximal esophageal contraction. In globus patients with GERD, the temporal and spatial dimension of the transitional zone were greater among negative responders than among PPI-positive responders (P=0.010 and P=0.011). Regarding GERD patients without globus, there was no significant difference in transition zone defect according to PPI responsiveness. By receiver operating characteristic curve analysis, 2.1 cm and 1.1 s were found to be the spatial and temporal transitional zone dimensions that best differentiated positive and negative responders. CONCLUSION: In patients with GERD-related globus, there were larger transition zone defect in the negative responders compared with the PPI-positive responders.

Ganoderma lucidum ethanol extract inhibits the inflammatory response by suppressing the NF-κB and toll-like receptor pathways in lipopolysaccharide-stimulated BV2 microglial cells.

Ganoderma lucidum is a traditional Oriental medicine that has been widely used as a tonic to promote longevity and health in Korea and other Asian countries. Although a great deal of work has been carried out on the therapeutic potential of this mushroom, the pharmacological mechanisms of its anti-inflammatory actions remain unclear. In this study, we evaluated the inhibitory effects of G. lucidum ethanol extract (EGL) on the production of inflammatory mediators and cytokines in lipopolysaccharide (LPS)-stimulated murine BV2 microglia. We also investigated the effects of EGL on the LPS-induced activation of nuclear factor kappaB (NF-κB) and upregulation of toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88). Elevated levels of nitric oxide (NO), prostaglandin E(2) (PGE(2)) and pro-inflammatory cytokine production were detected in BV2 microglia following LPS stimulation. We identifed that EGL significantly inhibits the excessive production of NO, PGE(2) and pro-inflammatory cytokines, including interleukin (IL)-1ß and tumor necrosis factor-α in a concentration-dependent manner without causing cytotoxicity. In addition, EGL suppressed NF-κB translocation and transcriptional activity by blocking IκB degradation and inhibiting TLR4 and MyD88 expression in LPS-stimulated BV2 cells. Our results indicate that the inhibitory effects of EGL on LPS-stimulated inflammatory responses in BV2 microglia are associated with the suppression of the NF-κB and TLR signaling pathways. Therefore, EGL may be useful in the treatment of neurodegenerative diseases by inhibiting inflammatory mediator responses in activated microglia.

Prediction of esophageal variceal bleeding in B-viral liver cirrhosis using the P2/MS noninvasive index based on complete blood counts.

BACKGROUND/AIM: Periodic endoscopy for esophageal varices (EVs) and prophylactic treatment of high-risk EVs, i.e., medium/large EVs, small EVs with the red-color sign or decompensation, are recommended in cirrhotic patients. We assessed the cumulative risks for future EV bleeding using the following simple P2/MS index: (platelet count)2/[monocyte fraction (%) × segmented neutrophil fraction (%)]. METHODS: We enrolled 475 consecutive B-viral cirrhosis patients for 4 years, none of whom experienced EV bleeding. All underwent laboratory work-ups, endoscopy and ultrasonography. Those with EV bleeding took a nonselective ß-blocker as prophylaxis. The major endpoint was the first occurrence of EV bleeding, analyzed using the Kaplan-Meier and Cox regression methods. RESULTS: Among patients with EV bleeding (n = 131), 25 experienced their first EV bleeding during follow-up. To differentiate the risk for EV bleeding, we divided them into two subgroups according to their P2/MS value (subgroup 1: P2/MS ≥9 and subgroup 2: P2/MS <9). The risk was significantly higher in subgroup 2 (p = 0.029). From multivariate analysis, a lower P2/MS (p = 0.040) remained a significant predictor for EV bleeding along with large varix size (p = 0.015), red-color sign (p = 0.041) and Child-Pugh classification B/C (p = 0.001). In subgroup 1, the risk for EV bleeding was similar to that of patients with low-risk EVs (p = 0.164). CONCLUSIONS: The P2/MS is a reliable predictor for the risk of EV bleeding among patients with EV bleeding. According to risk stratification, different prophylactic treatments should be considered for the subgroup with a P2/MS <9.

Protective effects of chitosan oligosaccharide on paraquat-induced nephrotoxicity in rats.

We investigated the apoptotic pathway during paraquat (PQ)-induced nephrotoxicity as well as renoprotective effects of chitosan oligosaccharide (COS) in male Sprague-Dawley rats because increasing evidences suggest that antioxidants may prevent PQ-induced apoptosis. Animals were pretreated with normal saline or COS (500 mg/kg, p.o.) 3 days before PQ (60 mg/kg, i.p.) administration, and were sacrificed at scheduled times after PQ administration. Rats administered PQ showed increased serum PQ concentrations, blood urea nitrogen, and creatinine levels in a time-dependent manner and creatinine clearance was decreased compared with control rats. All of these parameters were reversed significantly by COS pretreatment. After the PQ injection, cell deaths occurred in the proximal renal tubules with increased APE, PUMA, and cleaved caspase-3 expression, while APE and cleaved caspase-3 were immunolocalized mainly in the proximal tubules of control kidneys. COS-pretreated rat kidneys showed increased expression of the above parameters before PQ injection. APE and cleaved caspase-3 were immunolocalized ubiquitously in the renal cortex of COS-pretreated rats until 24h after the PQ injection. These results showed that PQ-induced nephrotoxicity may be caused by apoptosis in rat kidneys and that COS could protect kidneys from PQ-induced toxicity in association with the basal higher level of APE.