791 research outputs found

    Computational modelling identifies impact of subtle anatomical variation on skeletal muscle local calcium dynamics

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    Calcium is the main regulator of skeletal muscle metabolic activity. The question has been addressed whether the highly structured spatial organization of sites of Ca2+ release, uptake and action in skeletal muscle substantially impacts the dynamics of cytosolic Ca2+ handling and thereby the physiology of the cell. Hereto, the spatiotemporal dynamics of the free calcium distribution in a fast-twitch muscle sarcomere was studied using a reaction-diffusion computational model. The model was based on the model of Baylor and Hollingworth (J Gen Physiol. 1998 112:297–316), but was adapted to handle local calcium dynamics in mouse EDL fast twitch muscle at 35C. Furthermore, the Ca2+ mass balance was closed by adding a mathematical representation of the sarcoplasmic reticulum. Experimental calcium time courses (high time resolution, but spatially averaged) obtained under physiological conditions (35C, 125 Hz stimulation frequency) were used for model validation. The model showed that subtle changes in sarcomere microstructure influenced the local calcium concentration. Furthermore, local calcium concentration sensed by mitochondria was higher than average calcium concentration and also above the activation constant of the mitochondria, whereas the local concentration was not. Furthermore, the free Ca2+ concentration was higher at the positions with troponin C than without troponin C

    Identifying and Investigating Intrusive Scanning Patterns by Visualizing Network Telescope Traffic in a 3-D Scatter-plot

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    Detecting and investigating intrusive Internet activity is an ever-present challenge for network administrators and security researchers. Network monitoring can generate large, unmanageable amounts of log data, which further complicates distinguishing between illegitimate and legiti-mate traffic. Considering the above issue, this article has two aims. First, it describes an investigative methodology for network monitoring and traffic review; and second, it discusses results from applying this meth-od. The method entails a combination of network telescope traffic cap-ture and visualisation. Observing traffic from the perspective of a dedi-cated sensor network reduces the volume of data and alleviates the concern of confusing malicious traffic with legitimate traffic. Compliment-ing this, visual analysis facilitates the rapid review and correlation of events, thereby utilizing human intelligence in the identification of scan-ning patterns. To demonstrate the proposed method, several months of network telescope traffic is captured and analysed with a tailor made 3D scatter-plot visualisation. As the results show, the visualisation saliently conveys anomalous patterns, and further analysis reveals that these patterns are indicative of covert network probing activity. By incorporat-ing visual analysis with traditional approaches, such as textual log re-view and the use of an intrusion detection system, this research contrib-utes improved insight into network scanning incidents

    Identifying user preferences for a digital educational solution for young seniors with diabetes

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    The Eindhoven Diabetes Education Simulator project was initiated to develop an educational solution that helps diabetes patients understand and learn more about their diabetes. This article describes the identification of user preferences for the development of such solutions. Young seniors (aged 50-65 years) with type 2 diabetes were chosen as the target group because they are likely to have more affinity with digital devices than older people and because 88% of the Dutch diabetes population is > 50 years of age. Data about the target group were gathered through literature research and interviews. The literature research covered data about their device use and education preferences. To gain insight into the daily life of diabetes patients and current diabetes education processes, 20 diabetes patients and 10 medical experts were interviewed. The interviews were analyzed using affinity diagrams. Those diagrams, together with the literature data, formed the basis for two personas and corresponding customer journey maps. Literature showed that diabetes prevalence is inversely correlated to educational level. Computer and device use is relatively low within the target group, but is growing. The interviews showed that young seniors like to play board, card, and computer games, with others or alone. Family and loved ones play an important role in their lives. Medical experts are crucial in the diabetes education of young senior diabetes patients. These findings are translated into a list of design aspects that can be used for creating educational solutions

    Inetvis: a graphical aid for the detection and visualisation of network scans

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    This paper presents an investigative analysis of network scans and scan detection algorithms. Visualisation is employed to review network telescope traffic and identify incidents of scan activity. Some of the identified phenomena appear to be novel forms of host discovery. The scan detection algorithms of Snort and Bro are critiqued by comparing the visualised scans with alert output. Where human assessment disa-grees with the alert output, explanations are sought after by analysing the detection algorithms. The algorithms of the Snort and Bro intrusion detection systems are based on counting unique connection attempts to destination addresses and ports. For Snort, notable false positive and false negative cases result due to a grossly oversimplified method of counting unique destination addresses and ports

    Towards automatic pulmonary nodule management in lung cancer screening with deep learning

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    The introduction of lung cancer screening programs will produce an unprecedented amount of chest CT scans in the near future, which radiologists will have to read in order to decide on a patient follow-up strategy. According to the current guidelines, the workup of screen-detected nodules strongly relies on nodule size and nodule type. In this paper, we present a deep learning system based on multi-stream multi-scale convolutional networks, which automatically classifies all nodule types relevant for nodule workup. The system processes raw CT data containing a nodule without the need for any additional information such as nodule segmentation or nodule size and learns a representation of 3D data by analyzing an arbitrary number of 2D views of a given nodule. The deep learning system was trained with data from the Italian MILD screening trial and validated on an independent set of data from the Danish DLCST screening trial. We analyze the advantage of processing nodules at multiple scales with a multi-stream convolutional network architecture, and we show that the proposed deep learning system achieves performance at classifying nodule type that surpasses the one of classical machine learning approaches and is within the inter-observer variability among four experienced human observers.Comment: Published on Scientific Report

    Smart shops: a survey of products, claimed effects and medical-toxicological relevance

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    During the last few years the use of herbal drugs of abuse, so-called 'smart products' and eco-drugs has increased. Many of these products have psychoactive effects. The variety of smart products sold in the so-called smart shops is enormous and this is still a growing market. The increased availability of these products and the continuing appearance of new products on the market, has led to increased awareness of the possible negative health aspects associated with the use of these products. At present, the Dutch Inspectorate for Health Protection, Commodities and Veterinary Public Health is testing the activities of these smart shops and the products for adherence to the regulations. This document, prepared by the National Poisons Control Centre (NVIC) of the National Institute of Public Health and the Environment (RIVM), serves as a practical aid to the Inspectorate in evaluating the various smart products. Four important groups of smart products can be discerned: the energizers, relaxing herbs, aphrodisiacs and products with hallucinogenic properties. For each of these groups the following items are described: the various product appearances, usage, the (desired) effects of the product according to smart shop information brochures, a description of the original plants (most of these products are derived from plants), the active ingredients in the product, and to the best of our knowledge, the pharmacology and medical toxicology of these ingredients and products. Further monitoring of the use of these smart products and the health effects they cause, should make clear to which specific group of smart products most attention should be paid from a medical point of view.Het gebruik van zogenaamde smartproducts en eco-drugs neemt de laatste jaren steeds meer toe. Het aanbod van producten die in de smartshops worden verkocht is zeer divers. Veel van de aangeboden middelen hebben psychoactieve effecten. Bovendien is het een uiterst dynamische markt, waar regelmatig nieuwe producten ontwikkeld en verkocht worden. Door deze groeiende markt wordt ook van overheidswege aandacht besteed aan de gezondheids- en maatschappelijke risico's van het gebruik en de verkoop van deze middelen. In het huidige beleid ten aanzien van deze middelen ligt de nadruk op gezondheidsbescherming met behulp van voorlichting, monitoring en onderzoek. In dit kader toetst in 1999 de Inspectie Gezondheidsbescherming, Waren en Veterinaire Zaken de activiteiten van smartshops en andere verkooppunten, alsmede de verhandelde waar, aan de warenwettelijke kaders. Zonodig wordt nieuwe jurisprudentie opgebouwd. Dit rapport, geschreven op verzoek van en in samenwerking met de Inspectie Gezondheidsbescherming, Waren en Veterinaire Zaken dient de Inspectie tot een praktisch hulpmiddel bij het evalueren van de vele verschillende producten die op de markt aanwezig zijn. Op grond van het belangrijkste beoogde effect dat deze middelen na gebruik zouden verschaffen, zijn de producten ingedeeld in een van de vier te onderscheiden functionele groepen, te weten de "energizers", "relaxing herbs", "afrodisiaca" en "hallucinogene producten". Per product(-groep) worden besproken: de verschillende productvoorkomens en wijze van gebruik, het in de smartshop gepropageerde doel van gebruik, de plantaardige herkomst van het product, en de samenstellende verbindingen met voor zover bekend hun farmacologische werkingsmechanismen en toxiciteit. Daarbij is gebruik gemaakt van de humaan medisch-toxicologische kennis zoals die op dit moment voorhanden is. Verdere monitoring naar de effecten van het gebruik zal inzichtelijk moeten maken naar welke productgroepen vanuit medisch oogpunt in de toekomst de meeste aandacht zal moeten uitgaan

    Ekstrak Virgin Coconut Oil Sebagai Sumber Pangan Fungsional

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    Virgin Coconut Oil (VCO) merupakan salah satu jenis minyak nabati yang dapat bermanfaat dari aspek medis dan nutrisi karena dapat mencegah dan membantu mengobati penyakit tertentu serta dapat mempermudah proses pencernaan makanan dan penyerapan gizi. VCO dapat bertindak sebagai antioksidan dan antifotooksidan yang disebabkan oleh kandungan komponen minor (mikronutrien). Tujuan penelitian ini adalah mengekstrak komponen minor VCO menjadi produk untuk pangan fungsional yang mampu berperan sebagai antioksidan dan mengetahui peran VCO sebagai antiradikal bebas secara in vitro. Penelitian ini menggunakan metode eksperimental dengan 3 tahap yaitu: 1. Ekstraksi VCO menggunakan pelarut etanol dan metanol, 2. Pengujian penangkapan radikal bebas ekstrak VCO secara in vitro dengan metode 1,1-difenil-2-pikrilhidrazil (DPPH), 3. Identifikasi dan pengujian komponen kimia pada ekstrak VCO, identifikasi dan pengujian komponen minor pada ekstrak VCO dengan menggunakan High Performance Liquid Chromatography (HPLC). Hasil penelitian ini menunjukkan bahwa rendemen ekstrak VCO semakin tinggi dengan semakin tingginya persentase pelarut, ekstraksi dengan menggunakan etanol menghasilkan rendemen ekstrak yang lebih tinggi dibanding dengan menggunakan metanol. Aktivitas antioksidan dan kandungan total tokoferol dari ekstrak VCO semakin tinggi dengan semakin tingginya persentase pelarut yang digunakan. Salah satu senyawa tokoferol yang terdapat dalam VCO adalah -tokoferol. Berdasarkan analisa statistik menunjukkan bahwa etanol dan metanol menghasilkan sifat kimia ekstrak yang relatif sama, sehingga dapat direkomendasikan bahwa untuk mengekstraksi komponen minor dari VCO dapat menggunakan etanol karena di samping aman dari aspek kesehatan juga dapat menghasilkan rendemen ekstrak yang lebih tinggi

    In Silico Analysis Identifies Intestinal Transit as a Key Determinant of Systemic Bile Acid Metabolism

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    Bile acids fulfill a variety of metabolic functions including regulation of glucose and lipid metabolism. Since changes of bile acid metabolism accompany obesity, Type 2 Diabetes Mellitus and bariatric surgery, there is great interest in their role in metabolic health. Here, we developed a mathematical model of systemic bile acid metabolism, and subsequently performed in silico analyses to gain quantitative insight into the factors determining plasma bile acid measurements. Intestinal transit was found to have a surprisingly central role in plasma bile acid appearance, as was evidenced by both the necessity of detailed intestinal transit functions for a physiological description of bile acid metabolism as well as the importance of the intestinal transit parameters in determining plasma measurements. The central role of intestinal transit is further highlighted by the dependency of the early phase of the dynamic response of plasma bile acids after a meal to intestinal propulsion
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