51 research outputs found

    Anomalous electron heating effects on the E region ionosphere in TIEGCM

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    We have recently implemented a new module that includes both the anomalous electron heating and the electron‐neutral cooling rate correction associated with the Farley‐Buneman Instability (FBI) in the thermosphere‐ionosphere electrodynamics global circulation model (TIEGCM). This implementation provides, for the first time, a modeling capability to describe macroscopic effects of the FBI on the ionosphere and thermosphere in the context of a first‐principle, self‐consistent model. The added heating sources primarily operate between 100 and 130 km altitude, and their magnitudes often exceed auroral precipitation heating in the TIEGCM. The induced changes in E region electron temperature in the auroral oval and polar cap by the FBI are remarkable with a maximum Te approaching 2200 K. This is about 4 times larger than the TIEGCM run without FBI heating. This investigation demonstrates how researchers can add the important effects of the FBI to magnetosphere‐ionosphere‐thermosphere models and simulators.NNX14Al13G - NASA GCR; NASA LWS; NNX14AE06G; NNX15AB83G; NNX12AJ54G - NASA HGI; ACI-1053575 - National Science Foundatio

    Early prediction of survival after open surgical repair of ruptured abdominal aortic aneurysms

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    Background: Scoring models are widely established in the intensive care unit (ICU). However, the importance in patients with ruptured abdominal aortic aneurysm (RAAA) remains unclear. Our aim was to analyze scoring systems as predictors of survival in patients undergoing open surgical repair (OSR) for RAAA. Methods: This is a retrospective study in critically ill patients in a surgical ICU at a university hospital. Sixty-eight patients with RAAA were treated between February 2005 and June 2013. Serial measurements of Sequential Organ Failure Assessment score (SOFA), Simplified Acute Physiology Score II (SAPS II) and Simplified Therapeutic Intervention Scoring System-28 (TISS-28) were evaluated with respect to in-hospital mortality. Eleven patients had to be excluded from this study because 6 underwent endovascular repair and 5 died before they could be admitted to the ICU. Results: All patients underwent OSR. The initial, highest, and mean of SOFA and SAPS II scores correlated significant with in-hospital mortality. In contrast, TISS-28 was inferior and showed a smaller area under the receiver operating curve. The cut-off point for SOFA showed the best performance in terms of sensitivity and specificity. An initial SOFA score below 9 predicted an in-hospital mortality of 16.2% (95% CI, 4.3–28.1) and a score above 9 predicted an in-hospital mortality of 73.7% (95% CI, 53.8–93.5, p 45), the in-hospital mortality rate was 85.7% (95% CI, 67.4–100, p < 0.01) versus 31.6% (95% CI, 10.7–52.5, p = 0.01) when it decreased. On multiple regression analysis, only the mean of the SOFA score showed a significant predictive capacity with regards to mortality (odds ratio 1.77; 95% CI, 1.19–2.64; p < 0.01). Conclusion: SOFA and SAPS II scores were able to predict in-hospital mortality in RAAA within 48 h after OSR. According to cut-off points, an increase or decrease in SOFA and SAPS II scores improved sensitivity and specificity

    The collateral caval shunt as an alternative to classical shunt procedures in patients with recurrent duodenal varices and extrahepatic portal vein thrombosis

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    Upper gastrointestinal bleeding episodes from variceal structures are severe complications in patients with portal hypertension. Endoscopic sclerotherapy and variceal ligation are the treatment options preferred for upper variceal bleeding owing to extrahepatic portal hypertension due to portal vein thrombosis (PVT). Recurrent duodenal variceal bleeding in non-cirrhotic patients with diffuse porto-splenic vein thrombosis and subsequent portal cavernous transformation represent a clinical challenge if classic shunt surgery is not possible or suitable. In this study, we represent a case of recurrent bleeding of duodenal varices in a non-cirrhotic patient with cavernous transformation of the portal vein that was successfully treated with a collateral caval shunt operation

    Comparison of predictive estimates of high‐latitude electrodynamics with observations of global‐scale Birkeland currents

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    Two of the geomagnetic storms for the Space Weather Prediction Center Geospace Environment Modeling challenge occurred after data were first acquired by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE). We compare Birkeland currents from AMPERE with predictions from four models for the 4–5 April 2010 and 5–6 August 2011 storms. The four models are the Weimer (2005b) field‐aligned current statistical model, the Lyon‐Fedder‐Mobarry magnetohydrodynamic (MHD) simulation, the Open Global Geospace Circulation Model MHD simulation, and the Space Weather Modeling Framework MHD simulation. The MHD simulations were run as described in Pulkkinen et al. (2013) and the results obtained from the Community Coordinated Modeling Center. The total radial Birkeland current, ITotal, and the distribution of radial current density, Jr, for all models are compared with AMPERE results. While the total currents are well correlated, the quantitative agreement varies considerably. The Jr distributions reveal discrepancies between the models and observations related to the latitude distribution, morphologies, and lack of nightside current systems in the models. The results motivate enhancing the simulations first by increasing the simulation resolution and then by examining the relative merits of implementing more sophisticated ionospheric conductance models, including ionospheric outflows or other omitted physical processes. Some aspects of the system, including substorm timing and location, may remain challenging to simulate, implying a continuing need for real‐time specification.Key PointsPresents the first comparison between observed field‐aligned currents and models previously evaluated for space weather operational useThe model and observed integrated currents are well correlated, but the ratio between them ranges from 1/3 to 3The 2‐D current densities are weakly correlated with observations implying significant areas for improvements in the modelsPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136469/1/swe20415_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136469/2/swe20415.pd

    On-line monitoring and controlling of cell apoptosis in mammalian cell culture processes using dielectric spectroscopy

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    We investigate a method to control critical quality attributes and apply Process Analytical Technology (PAT) via online dielectric spectroscopy (DS) feedback. This system has been intensively explored and successfully implemented in GMP manufacturing processes at Biogen. The present bioreactor application however, is basic and only allows the prediction of biomass. To further enhance the cell culture process robustness, we investigated the feasibility of using the full-spectrum dielectric spectroscopy scanning function to detect dielectric property changes in the cells associated with shifts in cell health and/or metabolism. In this proof of concept study, we used several CHO cell processes to demonstrate that DS probes can be used to not only measure the biomass but also reflect the cell’s physiological state changes (e.g. cell apoptosis). The results showed that one or more of the key parameters of delta capacitance (De), critical frequency (fc), and Cole-Cole Alpha (a) from the multi-frequency scanning data could reflect the cell’s early apoptosis induced by chemical treatment, nutrient depletion, or shear stress, which were seen earlier than that obtained from off-line methods (e.g. trypan blue exclusion). In some cases, by responding to the earlier detection, the cell apoptosis was reversed in time and the batch was saved. This enables a potential application, transferrable across programs, of full-spectrum dielectric spectroscopy for earlier detection of physiological changes, allowing for timelier bioreactor process adjustments. In addition, the feasibility of the application of multifrequency scanning in cGMP process for monitoring and control was also explored in this study

    The value of hepatic resection in metastasic renal cancer in the era of Tyrosinkinase Inhibitor Therapy

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    Background: The value of liver-directed therapy (LDT) in patients with metastasic renal cell carcinoma (MRCC) is still an active field of research, particularly in the era of tyrosinkinase inhibitor (TKI) therapy. Methods: The records of 35 patients with MRCC undergoing LDT of metastasic liver lesions between 1992 and 2015 were retrospectively analyzed. Immediate postoperative TKI was given in a subgroup of patients after LDT for metastasic lesions. Uni- and multivariate models were applied to assess overall survival (OS), progression-free survival (PFS) and disease-free survival (DFS). Results: Following primary tumor (renal cell cancer) resection and LDT, respectively, median OS was better for a total of 16 patients (41 %) receiving immediate postoperative TKI with 151 and 98 months, when compared to patients without TKI therapy with 61 (p = 0.003) and 40 months (p = 0.032). Immediate postoperative TKI was associated with better median PFS (47 months versus 19 months; p = 0.023), whereas in DFS only a trend was observed (51 months versus 19 months; p = 0.110). Conclusions: LDT should be considered as a suitable additive tool in the era of TKI therapy of MRCC to the liver. In this context, postoperative TKI therapy seems to be associated with better OS and PFS, but not DFS

    TIE2-expressing monocytes and M2-polarized macrophages impact survival and correlate with angiogenesis in adenocarcinoma of the pancreas

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    Introduction: M2-polarized tumor-associated macrophages (TAMs) and TIE2- expressing monocytes (TEMs) are associated with angiogenesis and have been identified as a potential prognostic marker in several solid tumors, including hepatobiliary malignancies. However, little is known regarding their influence on tumor progression and patient survival in pancreatic ductal adenocarcinoma (PDAC). Results: Patients with tumors characterized by the presence of CD163+ TAMs or TEMs in TCA or TIF, respectively, showed a significantly decreased 1-, 3- and 5-year overall and recurrence-free survival compared to patients without CD163+ TAMs or TEMs (all ρ < 0.05). Patients with TEMs in TCA showed a higher incidence of tumor recurrence (ρ < 0.05). Furthermore, the presence of CD163+ TAMs was associated with a higher tumor MVD (ρ < 0.05). Conclusions: Presence of M2-polarized TAMs and TEMs is associated with a decreased overall and recurrence-free survival of patients with PDAC. Materials and methods: The localization and density of CD163+ M2-polarized TAMs and TEMs were quantified in the tumor central area (TCA) and tumor-infiltrating front (TIF) in human PDAC tissue (n = 106) and correlated to clinicopathological characteristics, tumor recurrence rates and patient survival. In parallel, tumor microvascular density (MVD) and the density of angiopoietin-positive tumor cells were quantified. Statistical analysis was performed using SPSS software
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