Noise enhancement due to quantum coherence in coupled quantum dots

We show that the intriguing observation of noise enhancement in the charge transport through two vertically coupled quantum dots can be explained by the interplay of quantum coherence and strong Coulomb blockade. We demonstrate that this novel mechanism for super-Poissonian charge transfer is very sensitive to decoherence caused by electron-phonon scattering as inferred from the measured temperature dependence.Comment: 4 pages, 3 figures, corrected version (Figs.2 and 3

Shot noise in resonant tunneling through a zero-dimensional state with a complex energy spectrum

We investigate the noise properties of a GaAs/AlGaAs resonant tunneling structure at bias voltages where the current characteristic is determined by single electron tunneling. We discuss the suppression of the shot noise in the framework of a coupled two-state system. For large bias voltages we observed super-Poissonian shot noise up to values of the Fano factor $\alpha \approx 10$.Comment: 4 pages, 4 figures, accepted for Phys. Rev.

Novel application of low pH-dependent fluorescent dyes to examine colitis

<p>Abstract</p> <p>Background</p> <p>Endoscopy capable of fluorescence observation provides histological information on gastrointestinal lesions. We explored the novel application of low pH-dependent fluorescent dyes for fluorescence observation of crypt structure and inflammatory cell infiltration in the colon.</p> <p>Methods</p> <p>Low pH-dependent fluorescent dyes were applied to the colonic mucosa of normal mice for observation under fluorescence stereomicroscopy system. We also examined mouse models of colitis, which were induced by trinitrobenzenesulfonic acid, dextran sulfate sodium or interleukin-10 deficiency.</p> <p>Results</p> <p>Topical application of low pH-dependent fluorescent dyes revealed crypts as ring-shaped fluorescent stains by visualizing the mucin granules of goblet cells. Because of the minimal fluorescence intensity of the low pH-dependent fluorescent dyes in phosphate-buffered saline, it was not necessary to wash the mucosa before the fluorescence observation. 4-Nitro-7-piperazino-2,1,3-benzoxadiazole (NBD-PZ) was quicker to achieve complete staining (three minutes) than LysoSensor Green DND-153 and DND-189 (20 minutes). In each type of colitis, NBD-PZ revealed the destruction of the crypts as the disappearance of the ring-shaped fluorescent stains and the infiltration of inflammatory cells as the aggregation of punctate fluorescent stains through visualization of lysosomes.</p> <p>Conclusions</p> <p>Low pH-dependent fluorescent dyes, especially NBD-PZ, are suitable for topical application to the colonic mucosa and have characteristics that allow for the histological examination of colitis.</p

Endomicroscopic and transcriptomic analysis of impaired barrier function and malabsorption in environmental enteropathy

Introduction: Environmental enteropathy (EE) is associated with growth failure, micronutrient malabsorption and impaired responses to oral vaccines. We set out to define cellular mechanisms of impaired barrier function in EE and explore protective mechanisms. Methods: We studied 49 adults with environmental enteropathy in Lusaka, Zambia using confocal laser endomicroscopy (CLE); histology, immunohistochemistry and mRNA sequencing of small intestinal biopsies; and correlated these with plasma lipopolysaccharide (LPS) and a zinc uptake test. Results: CLE images (median 134 for each study) showed virtually ubiquitous small intestinal damage. Epithelial defects, imaged by histology and claudin 4 immunostaining, were predominantly seen at the tips of villi and corresponded with leakage imaged in vivo by CLE. In multivariate analysis, circulating log-transformed LPS was correlated with cell shedding events (β = 0.83; P = 0.035) and with serum glucagon-like peptide-2 (β = -0.13; P = 0.007). Zinc uptake from a test dose of 25mg was attenuated in 30/47 (64%) individuals and in multivariate analysis was reduced by HIV, but positively correlated with GLP-2 (β = 2.72; P = 0.03). There was a U-shaped relationship between circulating LPS and villus surface area. Transcriptomic analysis identified 23 differentially expressed genes in severe enteropathy, including protective peptides and proteins. Conclusions: Confocal endomicroscopy, claudin 4 immunostaining and histology identify epithelial defects which are probably sites of bacterial translocation, in the presence of which increased epithelial surface area increases the burden of translocation. GLP 2 and other protective peptides may play an important role in mucosal protection in EE

Endoscopic anterior fundoplication with the Medigus Ultrasonic Surgical Endostapler (MUSE™) for gastroesophageal reflux disease: 6-month results from a multi-center prospective trial

BACKGROUND: Both long-term proton pump inhibitor (PPI) use and surgical fundoplication have potential drawbacks as treatments for chronic gastroesophageal reflux disease (GERD). This multi-center, prospective study evaluated the clinical experiences of 69 patients who received an alternative treatment: endoscopic anterior fundoplication with a video- and ultrasound-guided transoral surgical stapler. METHODS: Patients with well-categorized GERD were enrolled at six international sites. Efficacy data was compared at baseline and at 6 months post-procedure. The primary endpoint was a ≥ 50 % improvement in GERD health-related quality of life (HRQL) score. Secondary endpoints were elimination or ≥ 50 % reduction in dose of PPI medication and reduction of total acid exposure on esophageal pH probe monitoring. A safety evaluation was performed at time 0 and weeks 1, 4, 12, and 6 months. RESULTS: 66 patients completed follow-up. Six months after the procedure, the GERD-HRQL score improved by >50 % off PPI in 73 % (48/66) of patients (95 % CI 60-83 %). Forty-two patients (64.6 %) were no longer using daily PPI medication. Of the 23 patients who continued to take PPI following the procedure, 13 (56.5 %) reported a ≥ 50 % reduction in dose. The mean percent of total time with esophageal pH <4.0 decreased from baseline to 6 months (P < 0.001). Common adverse events were peri-operative chest discomfort and sore throat. Two severe adverse events requiring intervention occurred in the first 24 subjects, no further esophageal injury or leaks were reported in the remaining 48 enrolled subjects. CONCLUSIONS: The initial 6-month data reported in this study demonstrate safety and efficacy of this endoscopic plication device. Early experience with the device necessitated procedure and device changes to improve safety, with improved results in the later portion of the study. Continued assessment of durability and safety are ongoing in a three-year follow-up study of this patient group

Confocal laser endomicroscopy is a new imaging modality for recognition of intramucosal bacteria in inflammatory bowel disease in vivo

Interaction of bacteria with the immune system within the intestinal mucosa plays a key role in the pathogenesis of inflammatory bowel disease (IBD). The aim of the current study was to develop a fluorescein-aided confocal laser endomicroscopy (CLE) method to visualise intramucosal enteric bacteria in vivo and to determine the involved mucosal area in the colon and ileum in patients with ulcerative colitis (UC) and Crohn's disease (CD)

Hallstatt miners consumed blue cheese and beer during the Iron Age and retained a non-Westernized gut microbiome until the Baroque period

21openInternationalInternational coauthor/editorWe subjected human paleofeces dating from the Bronze Age to the Baroque period (18th century AD) to in-depth microscopic, metagenomic, and proteomic analyses. The paleofeces were preserved in the underground salt mines of the UNESCO World Heritage site of Hallstatt in Austria. This allowed us to reconstruct the diet of the former population and gain insights into their ancient gut microbiome composition. Our dietary survey identified bran and glumes of different cereals as some of the most prevalent plant fragments. This highly fibrous, carbohydrate-rich diet was supplemented with proteins from broad beans and occasionally with fruits, nuts, or animal food products. Due to these traditional dietary habits, all ancient miners up to the Baroque period have gut microbiome structures akin to modern non-Westernized individuals whose diets are also mainly composed of unprocessed foods and fresh fruits and vegetables. This may indicate a shift in the gut community composition of modern Westernized populations due to quite recent dietary and lifestyle changes. When we extended our microbial survey to fungi present in the paleofeces, in one of the Iron Age samples, we observed a high abundance of Penicillium roqueforti and Saccharomyces cerevisiae DNA. Genome-wide analysis indicates that both fungi were involved in food fermentation and provides the first molecular evidence for blue cheese and beer consumption in Iron Age Europe.openMaixner, Frank; Sarhan, Mohamed S; Huang, Kun D; Tett, Adrian; Schoenafinger, Alexander; Zingale, Stefania; Blanco-Míguez, Aitor; Manghi, Paolo; Cemper-Kiesslich, Jan; Rosendahl, Wilfried; Kusebauch, Ulrike; Morrone, Seamus R; Hoopmann, Michael R; Rota-Stabelli, Omar; Rattei, Thomas; Moritz, Robert L; Oeggl, Klaus; Segata, Nicola; Zink, Albert; Reschreiter, Hans; Kowarik, KerstinMaixner, F.; Sarhan, M.S.; Huang, K.D.; Tett, A.; Schoenafinger, A.; Zingale, S.; Blanco-Míguez, A.; Manghi, P.; Cemper-Kiesslich, J.; Rosendahl, W.; Kusebauch, U.; Morrone, S.R.; Hoopmann, M.R.; Rota-Stabelli, O.; Rattei, T.; Moritz, R.L.; Oeggl, K.; Segata, N.; Zink, A.; Reschreiter, H.; Kowarik, K

To Biopsy or Not to Biopsy: Evaluation of a Large German Cohort of Patients with Abnormal Liver Tests of Unknown Etiology

Background and Aims: Despite increasingly sensitive and accurate blood tests to detect liver disease, liver biopsy remains very useful in patients with atypical clinical features and abnormal liver tests of unknown etiology. The aim was to determine those elevated laboratory liver parameters that cause the clinician to order a biopsy, and whether laboratory tests are associated with pathological findings on histology. Methods: 504 patients with unclear hepatopathy, admitted to the outpatient clinic of a university hospital between 2007 and 2010, were analyzed with respect to laboratory results, clinical data, and the results of liver biopsies. Results: Aspartate aminotransferase (AST) and glutamate dehydrogenase (GLDH) levels above the normal range significantly increased the likelihood of recommending a liver biopsy by 81% [OR with 95% CI 1.81 (1.21-2.71), p = 0.004] and 159% [OR with 95% CI 2.59 (1.70-3.93), p < 0.001], respectively. AST values above normal were associated with fibrosis (63 vs. 40% for normal AST, p = 0.010). Elevated ferritin levels pointed to a higher incidence of steatosis (48 vs. 10% for normal ferritin, p < 0.001) and inflammation (87 vs. 62% for normal ferritin, p = 0.004). Conclusions: Our results indicate that elevated AST and GLDH were associated with a greater likelihood of recommending liver biopsy. Elevated AST and ferritin levels were associated with steatosis, inflammation and fibrosis on liver biopsies. Thus, AST and ferritin may be useful non-invasive predictors of liver pathology in patients with unclear hepatopathy