29 research outputs found

    How does a biopsy of endoscopically normal terminal ileum contribute to the diagnosis? Which patients should undergo biopsy?

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    Background: Terminal ileum endoscopy and biopsy are the diagnostic tools of diseases attacking the ileum. However, abnormal histological findings can be found in endoscopically normal terminal ileum.Objective: This study was performed to evaluate the histopathological results of biopsies from endoscopically normal terminal ileum in order to determine pre-procedure clinical and laboratory factors predicting abnormal histopathological results, if any.Methods: A total of 297 patients who underwent colonoscopy and terminal ileum biopsy and had normal terminal ileum or a few aphthous ulcers in the terminal ileum together with completely normal colon mucosa were included in the study. The patients were grouped into two arms as normal cases and cases with aphthous ulcers. Histopathological and pre-procedural laboratory results of patients were analyzed according to their indications.Results: The terminal ileum was endoscopically normal in 200 patients, and 97 patients had aphthous ulcers. Chronic ileitis rate was present in 5.5% of those with endoscopically normal terminal ileum and in 39.2% of the patients with aphthous ulcers. In both groups, the highest rate of chronic ileitis was detected in the patients with known inflammatory bowel disease (IBD) (15.4 and 50%, respectively), anemia (9.5 and 43.5%, respectively), and in the patients having chronic diarrhea together with abdominal pain (7.7 and 44.8%, respectively). We found that the sensitivity of mean platelet volume for predicting chronic ileitis was 87% and the specificity was 45% at a cut-off value lower than 9.35 fl.Conclusion: In anemia indication or chronic diarrhea together with abdominal pain, the frequency of aphthous ulcers detected by ileoscopy and the frequency of chronic ileitis detected histopathologically despite a normal-appearing ileum were elevated.Keywords: Terminal ileum; ileoscopy; chronic ileitis; inflammatory bowel diseas

    Anti-cancer effects and mechanism of actions of aspirin analogues in the treatment of glioma cancer

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    INTRODUCTION: In the past 25 years only modest advancements in glioma treatment have been made, with patient prognosis and median survival time following diagnosis only increasing from 3 to 7 months. A substantial body of clinical and preclinical evidence has suggested a role for aspirin in the treatment of cancer with multiple mechanisms of action proposed including COX 2 inhibition, down regulation of EGFR expression, and NF-κB signaling affecting Bcl-2 expression. However, with serious side effects such as stroke and gastrointestinal bleeding, aspirin analogues with improved potency and side effect profiles are being developed. METHOD: Effects on cell viability following 24 hr incubation of four aspirin derivatives (PN508, 517, 526 and 529) were compared to cisplatin, aspirin and di-aspirin in four glioma cell lines (U87 MG, SVG P12, GOS – 3, and 1321N1), using the PrestoBlue assay, establishing IC50 and examining the time course of drug effects. RESULTS: All compounds were found to decrease cell viability in a concentration and time dependant manner. Significantly, the analogue PN517 (IC50 2mM) showed approximately a twofold increase in potency when compared to aspirin (3.7mM) and cisplatin (4.3mM) in U87 cells, with similar increased potency in SVG P12 cells. Other analogues demonstrated similar potency to aspirin and cisplatin. CONCLUSION: These results support the further development and characterization of novel NSAID derivatives for the treatment of glioma

    Population genomics of post-glacial western Eurasia.

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    Western Eurasia witnessed several large-scale human migrations during the Holocene <sup>1-5</sup> . Here, to investigate the cross-continental effects of these migrations, we shotgun-sequenced 317 genomes-mainly from the Mesolithic and Neolithic periods-from across northern and western Eurasia. These were imputed alongside published data to obtain diploid genotypes from more than 1,600 ancient humans. Our analyses revealed a 'great divide' genomic boundary extending from the Black Sea to the Baltic. Mesolithic hunter-gatherers were highly genetically differentiated east and west of this zone, and the effect of the neolithization was equally disparate. Large-scale ancestry shifts occurred in the west as farming was introduced, including near-total replacement of hunter-gatherers in many areas, whereas no substantial ancestry shifts happened east of the zone during the same period. Similarly, relatedness decreased in the west from the Neolithic transition onwards, whereas, east of the Urals, relatedness remained high until around 4,000 BP, consistent with the persistence of localized groups of hunter-gatherers. The boundary dissolved when Yamnaya-related ancestry spread across western Eurasia around 5,000 BP, resulting in a second major turnover that reached most parts of Europe within a 1,000-year span. The genetic origin and fate of the Yamnaya have remained elusive, but we show that hunter-gatherers from the Middle Don region contributed ancestry to them. Yamnaya groups later admixed with individuals associated with the Globular Amphora culture before expanding into Europe. Similar turnovers occurred in western Siberia, where we report new genomic data from a 'Neolithic steppe' cline spanning the Siberian forest steppe to Lake Baikal. These prehistoric migrations had profound and lasting effects on the genetic diversity of Eurasian populations

    Publisher Correction: Population genomics of post-glacial western Eurasia.

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    Nonlinear model selection for PARMA processes using RJMCMC

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    Many prediction studies using real life measurements such as wind speed, power, electricity load and rainfall utilize linear autoregressive moving average (ARMA) based models due to their simplicity and general character. However, most of the real life applications exhibit nonlinear character and modelling them with linear time series may become problematic. Among nonlinear ARMA models, polynomial ARMA (PARMA) models belong to the class of linear-in-the-parameters. In this paper, we propose a reversible jump Markov chain Monte Carlo (RJMCMC) based complete model estimation method which estimates PARMA models with all their parameters including the nonlinearity degree. The proposed method is unique in the manner of estimating the nonlinearity degree and all other model orders and model coefficients at the same time. Moreover, in this paper, RJMCMC has been examined in an anomalous way by performing transitions between linear and nonlinear model spaces

    Long term wind speed prediction with polynomial autoregressive model

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    Wind energy is one of the preferred energy generation methods because wind is an important renewable energy source. Prediction of wind speed in a time period, is important due to the one-to-one relationship between wind speed and wind power. Due to the nonlinear character of the wind speed data, nonlinear methods are known to produce better results compared to linear time series methods like Autoregressive (AR), Autoregressive Moving Average (ARMA) in predicting in a period longer than 12 hours. A method is proposed to apply a 48-hour ahead wind speed prediction by using the past wind speed measurements of the Çeşme Peninsula. We proposed to model wind speed data with a Polynomial AR (PAR) model. Coefficients of the models are estimated via linear Least Squares (LS) method and up to 48 hours ahead wind speed prediction is calculated for different models. In conclusion, a better performance is observed for higher than 12-hour ahead wind speed predictions of wind speed data which is modelled with PAR model, than AR and ARMA models

    Chitosan-Polyoxometalate Nanocomposites: Synthesis, Characterization and Application as Antimicrobial Agents

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    Polyoxometalates (POMs) were used, together with chitosan (CS), to obtain hybrid nanoaggregates. Three representative POMs were efficiently assembled into nanoparticles of few hundred nm diameter, featuring entangled ribbons substructure. In order to establish suitable preparation and stability conditions, the assemblies were characterized in solution by UV-Vis spectroscopy, dynamic light scattering and ζ-potential. The nanoparticles were tested against E. coli (106 CFU/ml) in aqueous solution, showing a synergic activity of the heteropolyacid H5PMo10V2O40 and CS. For such components, a highly porous and antibacterial film was obtained upon lyophilisation of the colloidal mixture. © 2014 Springer Science+Business Media New York

    Scale-Model And Simulation-Based Assessments For Design Alternatives Of Daylight Redirecting Systems In A Side-Lighting Educational Room

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    Daylight has been proven to have positive effects on well-being, comfort and performance of occupants in buildings; it specifically increases learning performance in educational buildings. Side-lighting from one direction leads to unbalanced and insufficient illuminance, especially in large and deep spaces. A design studio at the Izmir Institute of Technology (IZTECH) in Urla, Turkey, has been chosen as an example of a space in such a context. Its geometrical attributes has taken to be the baseline. First, four daylight redirecting systems are applied on its 1/15 scale model to understand and compare their redirection behavior visually. Second, measurements on the scale model are taken to compare the daylight illuminance distributions. Third, to assess the overall performance in the sunny climate, illuminance and luminance maps for photorealistic visualization are calculated in monthly steps over one year. For efficient calculation of the time-steps to be considered, the daylight coefficient method has been applied. Though light ducts are found to be effective for high sun angles, in summer and equinoxes; very low illuminance in entire space make them fail in winter. Light shelves are determined to be the most convenient ones for this space, since they provided sufficient, uniform and high illuminance in equinoxes and winter.Gün ışığının, bina kullanıcılarının refahı, konforu ve performansı üzerinde pozitif etkisi olduğu kanıtlanmıştır. Günışığı, özellikle, eğitim yapılarında öğrenme performansını da artıran bir etmendir. Tek yönlü yan aydınlatma, özellikle geniş ve derin hacimlerde, aydınlık düzeyinin dengesiz ve yetersiz olmasına yol açar. Bu bağlamda, İzmir Yüksek Teknoloji Enstitüsü (İYTE)’nde (Urla-Türkiye) bir tasarım stüdyosu, örnek olarak seçilmiştir. Geometrik özellikleri temel alınmıştır. İlk olarak, dört farklı ışık yönlendirme sistemi, ışık yönlendirme davranışlarının görsel olarak anlaşılması ve birbirleriyle karşılaştırılması için, 1/15 ölçekli makette uygulanmıştır. İkinci olarak, günışığı aydınlık düzeyi dağılımlarını karşılaştırabilmek için makette ölçümler yapılmıştır. Üçüncü olarak, performansın güneşli bir iklimde değerlendirilmesi amacıyla, aydınlık düzeyi ve fotogerçekçi görselleştirme adına parıltı dağılımları, tüm yıl boyunca aylık olarak hesaplanmıştır. Verimliliklerin istenilen zamanlarda hesaplanabilmesi için günışığı katsayısı yöntemi uygulanmıştır. Güneş açılarının yüksek olduğu durumlar için ışık bacalarının daha etkin olduğu bulunmuş; buna karşın, kışın tüm hacimdeki aydınlık düzeyi çok düşük olduğundan bu sistemler başarısız olmuştur. Işık rafları ise bu hacim için en uygun sistem olarak belirlenmiştir; çünkü bu sistemler, ekinoks ve yaz dönemlerinde aydınlık düzeyini yeterli bir şekilde, düzgün dağılımlı ve yüksek olarak sağlamıştır
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