278 research outputs found

    Analysis of body calcium (regional changes in body calcium by in vivo neutron activation analysis)

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    The effect of space flight on urine and fecal calcium loss was documented during the three long-term Skylab flights. Neutron activation analysis was used to determine regional calcium loss. Various designs for regional analysis were investigated

    Interplay between geometry and flow distribution in an airway tree

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    Uniform fluid flow distribution in a symmetric volume can be realized through a symmetric branched tree. It is shown here, however, that the flow partitioning can be highly sensitive to deviations from exact symmetry if inertial effects are present. This is found by direct numerical simulation of the Navier-Stokes equations in a 3D tree geometry. The flow asymmetry is quantified and found to depend on the Reynolds number. Moreover, for a given Reynolds number, we show that the flow distribution depends on the aspect ratio of the branching elements as well as their angular arrangement. Our results indicate that physiological variability should be severely restricted in order to ensure uniform fluid distribution in a tree. This study suggests that any non-uniformity in the air flow distribution in human lungs should be influenced by the respiratory conditions, rest or hard exercise

    Systems-Level Comparison of Host-Responses Elicited by Avian H5N1 and Seasonal H1N1 Influenza Viruses in Primary Human Macrophages

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    Human disease caused by highly pathogenic avian influenza (HPAI) H5N1 can lead to a rapidly progressive viral pneumonia leading to acute respiratory distress syndrome. There is increasing evidence from clinical, animal models and in vitro data, which suggests a role for virus-induced cytokine dysregulation in contributing to the pathogenesis of human H5N1 disease. The key target cells for the virus in the lung are the alveolar epithelium and alveolar macrophages, and we have shown that, compared to seasonal human influenza viruses, equivalent infecting doses of H5N1 viruses markedly up-regulate pro-inflammatory cytokines in both primary cell types in vitro. Whether this H5N1-induced dysregulation of host responses is driven by qualitative (i.e activation of unique host pathways in response to H5N1) or quantitative differences between seasonal influenza viruses is unclear. Here we used microarrays to analyze and compare the gene expression profiles in primary human macrophages at 1, 3, and 6 h after infection with H5N1 virus or low-pathogenic seasonal influenza A (H1N1) virus. We found that host responses to both viruses are qualitatively similar with the activation of nearly identical biological processes and pathways. However, in comparison to seasonal H1N1 virus, H5N1 infection elicits a quantitatively stronger host inflammatory response including type I interferon (IFN) and tumor necrosis factor (TNF)-α genes. A network-based analysis suggests that the synergy between IFN-β and TNF-α results in an enhanced and sustained IFN and pro-inflammatory cytokine response at the early stage of viral infection that may contribute to the viral pathogenesis and this is of relevance to the design of novel therapeutic strategies for H5N1 induced respiratory disease

    Direkter Nachweis der renalen Hyperämie nach intravenöser Injektion von Fursemid beim Hund

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    The effect of intravenous furosemide (1 mg/kg) body weight on the clearance of sodium-para-aminohippurate ( C PAH ) and on renal blood flow (electromagnetic flowmeter) was investigated under Nembutal anesthesia in 6 mongrel dogs. Renal blood flow, after a slight decrease, 20–30 sec after the Furosemide injection, increased rapidly and attained a mean value of +30.0% ( p <0.001) within the first 10 min. During the second 10 min, the increase averaged +23.1% ( p <0.0025) and dropped to +10.6% ( p <0.05) in the third 10 min period. The C PAH showed a similar pattern with mean increases of 24.8% ( p <0.05), 13.0% ( p <0.05) and +6.9% respectively. In 2 dogs, electromagnetic flowmeters were implanted on the renal artery and the same studies peformed without anesthesia. Again renal blood flow and C PAH increased in a similar way to that seen in the previous study, although the increase was slightly more pronounced. We conclude that the observed increase of C PAH in dogs after furosemide reflects a real increase of renal plasma flow and is not merely due to a washout effect. Bei 6 Bastard-Hunden wurde unter Nembutal-Narkose die Wirkung von Fursemid (1,0 mg/kg) Körpergewicht, i.v. injiziert auf die Natrium-Paraaminohippurat-Clearance ( C PAH ) und auf die renale Durchblutung, gemessen mit einem elektromagnetischen Durchflußmesser, untersucht. Die Nierendurchblutung nahm, nach einer wenige Sekunden dauernden leichten Abnahme, regelmäßig zu. Die größte Zunahme, im Mittel +30% ( p <0,001) trat innerhalb der ersten 10 min nach Fursemid auf. In den zweiten 10 min sank die mittlere Zunahme auf +23,1% ( p <0,0025), in den folgenden 10 min auf +10,6% ( p <0,05) ab. Die entsprechenden Werte für die C PAH lauten +24,8% ( p <0,05), +13,0% ( p <0,05) und +6,9% ( p <0,05). Um die Wirkung der Barbiturat-Narkose auszuschalten, wurden bei 2 Hunden mit implantierten elektromagnetischen Druckmessern dieselben Meßgrößen nach Fursemid in derselben Dosierung untersucht. Die Zunahme der Nierendurchblutung und der C PAH tritt auch unter diesen Bedingungen, sogar noch etwas ausgesprochener, auf. Wir schließen aus unseren Befunden daß die nach Fursemid beim Hund auftretende Zunahme der C PAH einer Zunahme der renalen Plasmadurchströmung, resp. der Nierendurchblutung entspricht und nicht auf einem „Auswasch“-Effekt beruht.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46305/1/210_2004_Article_BF00537179.pd

    Avalanches in Breakdown and Fracture Processes

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    We investigate the breakdown of disordered networks under the action of an increasing external---mechanical or electrical---force. We perform a mean-field analysis and estimate scaling exponents for the approach to the instability. By simulating two-dimensional models of electric breakdown and fracture we observe that the breakdown is preceded by avalanche events. The avalanches can be described by scaling laws, and the estimated values of the exponents are consistent with those found in mean-field theory. The breakdown point is characterized by a discontinuity in the macroscopic properties of the material, such as conductivity or elasticity, indicative of a first order transition. The scaling laws suggest an analogy with the behavior expected in spinodal nucleation.Comment: 15 pages, 12 figures, submitted to Phys. Rev. E, corrected typo in authors name, no changes to the pape

    A validated integrated clinical and molecular glioblastoma long-term survival-predictive nomogram.

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    Background: Glioblastoma (GBM) is the most common primary malignant brain tumor in adulthood. Despite multimodality treatments, including maximal safe resection followed by irradiation and chemotherapy, the median overall survival times range from 14 to 16 months. However, a small subset of GBM patients live beyond 5 years and are thus considered long-term survivors. Methods: A retrospective analysis of the clinical, radiographic, and molecular features of patients with newly diagnosed primary GBM who underwent treatment at The University of Texas MD Anderson Cancer Center was conducted. Eighty patients had sufficient quantity and quality of tissue available for next-generation sequencing and immunohistochemical analysis. Factors associated with survival time were identified using proportional odds ordinal regression. We constructed a survival-predictive nomogram using a forward stepwise model that we subsequently validated using The Cancer Genome Atlas. Results: Univariate analysis revealed 3 pivotal genetic alterations associated with GBM survival: both high tumor mutational burden ( Conclusions: Our newly devised long-term surviva

    How self-organized criticality works: A unified mean-field picture

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    We present a unified mean-field theory, based on the single site approximation to the master-equation, for stochastic self-organized critical models. In particular, we analyze in detail the properties of sandpile and forest-fire (FF) models. In analogy with other non-equilibrium critical phenomena, we identify the order parameter with the density of ``active'' sites and the control parameters with the driving rates. Depending on the values of the control parameters, the system is shown to reach a subcritical (absorbing) or super-critical (active) stationary state. Criticality is analyzed in terms of the singularities of the zero-field susceptibility. In the limit of vanishing control parameters, the stationary state displays scaling characteristic of self-organized criticality (SOC). We show that this limit corresponds to the breakdown of space-time locality in the dynamical rules of the models. We define a complete set of critical exponents, describing the scaling of order parameter, response functions, susceptibility and correlation length in the subcritical and supercritical states. In the subcritical state, the response of the system to small perturbations takes place in avalanches. We analyze their scaling behavior in relation with branching processes. In sandpile models because of conservation laws, a critical exponents subset displays mean-field values (ν=1/2\nu=1/2 and γ=1\gamma = 1) in any dimensions. We treat bulk and boundary dissipation and introduce a new critical exponent relating dissipation and finite size effects. We present numerical simulations that confirm our results. In the case of the forest-fire model, our approach can distinguish between different regimes (SOC-FF and deterministic FF) studied in the literature and determine the full spectrum of critical exponents.Comment: 21 RevTex pages, 3 figures, submitted to Phys. Rev.

    Do aluminium-based phosphate binders continue to have a role in contemporary nephrology practice?

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    Background: Aluminium-containing phosphate binders have long been used for treatment of hyperphosphatemia in dialysis patients. Their safety became controversial in the early 1980's after reports of aluminium related neurological and bone disease began to appear. Available historical evidence however, suggests that neurological toxicity may have primarily been caused by excessive exposure to aluminium in dialysis fluid, rather than aluminium-containing oral phosphate binders. Limited evidence suggests that aluminium bone disease may also be on the decline in the era of aluminium removal from dialysis fluid, even with continued use of aluminium binders

    Comparison of Two Quantitative Methods of Discerning Airspace Enlargement in Smoke-Exposed Mice

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    In this work, we compare two methods for evaluating and quantifying pulmonary airspace enlargement in a mouse model of chronic cigarette smoke exposure. Standard stereological sample preparation, sectioning, and imaging of mouse lung tissues were performed for semi-automated acquisition of mean linear intercept (Lm) data. After completion of the Lm measurements, D2, a metric of airspace enlargement, was measured in a blinded manner on the same lung images using a fully automated technique developed in-house. An analysis of variance (ANOVA) shows that although Lm was able to separate the smoke-exposed and control groups with statistical significance (p = 0.034), D2 was better able to differentiate the groups (p<0.001) and did so without any overlap between the control and smoke-exposed individual animal data. In addition, the fully automated implementation of D2 represented a time savings of at least 24x over semi-automated Lm measurements. Although D2 does not provide 3D stereological metrics of airspace dimensions as Lm does, results show that it has higher sensitivity and specificity for detecting the subtle airspace enlargement one would expect to find in mild or early stage emphysema. Therefore, D2 may serve as a more accurate screening measure for detecting early lung disease than Lm

    What is a smart device? - a conceptualisation within the paradigm of the internet of things

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    The Internet of Things (IoT) is an interconnected network of objects which range from simple sensors to smartphones and tablets; it is a relatively novel paradigm that has been rapidly gaining ground in the scenario of modern wireless telecommunications with an expected growth of 25 to 50 billion of connected devices for 2020 Due to the recent rise of this paradigm, authors across the literature use inconsistent terms to address the devices present in the IoT, such as mobile device, smart device, mobile technologies or mobile smart device. Based on the existing literature, this paper chooses the term smart device as a starting point towards the development of an appropriate definition for the devices present in the IoT. This investigation aims at exploring the concept and main features of smart devices as well as their role in the IoT. This paper follows a systematic approach for reviewing compendium of literature to explore the current research in this field. It has been identified smart devices as the primary objects interconnected in the network of IoT, having an essential role in this paradigm. The developed concept for defining smart device is based on three main features, namely context-awareness, autonomy and device connectivity. Other features such as mobility and userinteraction were highly mentioned in the literature, but were not considered because of the nature of the IoT as a network mainly oriented to device-to-device connectivity whether they are mobile or not and whether they interact with people or not. What emerges from this paper is a concept which can be used to homogenise the terminology used on further research in the Field of digitalisation and smart technologies
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