965 resultados para DISPERSIVE SHOCK-WAVES
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In 2009 Switzerland, for long an apparent beacon of European toleration and neutrality, voted to ban the erection of minarets. Internal religious matters are normally dealt with at the regional or local level – not at the level of the Swiss national parliament, although the state does seek to ensure good order and peaceful relations between different faith communities. Indeed, the freedom of these communities to believe and function publicly is enshrined in law. However, as a matter of national policy, now constitutionally embedded, one religious group, the Muslim group, is not permitted to build their distinctive religious edifice, the minaret. Switzerland may have joined the rest of Europe with respect to engaging the challenge of Islamic presence to European identity and values, but the rejection of a symbol of the presence of one faith – in this case, Islamic – by a society that is otherwise predominantly secular, pluralist, and of Christian heritage, poses significant concerns. How and why did this happen? What are the implications? This paper will discuss some of the issues involved, concluding the ban is by no means irreversible. Tolerant neutrality may yet again be a leitmotif of Swiss culture and not just of foreign policy.
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Byrd Glacier has one of the largest ice catchment areas in Antarctica, delivers more ice to the Ross Ice Shelf than any other ice stream, and is the fastest of these ice streams. A force balance, combined with a mass balance, demonstrates that stream flow in Byrd Glacier is transitional from sheet flow in East Antarctica to shelf flow in the Ross Ice Shelf. The longitudinal pulling stress, calculated along an ice flowband from the force balance, is linked to variations of ice thickness, to the ratio of the basal water pressure to the ice overburden pressure where Byrd Glacier is grounded, and is reduced by an ice-shelf buttressing stress where Byrd Glacier is floating. Longitudinal tension peaks at pressure-ratio maxima in grounded ice and close to minima in the ratio of the pulling stress to the buttressing stress in floating ice. The longitudinal spacing of these tension peaks is rather uniform and, for grounded ice, the peaks occur at maxima in surface slope that have no clear relation to the bed slope. This implies that the maxima in surface slope constitute a "wave train" that is related to regular variations in ice-bed coupling, not primarily to bed topography. It is unclear whether these surface "waves" are "standing waves" or are migrating either upslope or downslope, possibly causing the grounding line to either retreat or advance. Deciding which is the case will require obtaining bed topography in the map plane, a new map of surface topography, and more sophisticated modeling that includes ice flow linked to subglacial hydrology in the map plane.
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Cerebral electrical activity is highly nonstationary because the brain reacts to ever changing external stimuli and continuously monitors internal control circuits. However, a large amount of energy is spent to maintain remarkably stationary activity patterns and functional inter-relations between different brain regions. Here we examine linear EEG correlations in the peri-ictal transition of focal onset seizures, which are typically understood to be manifestations of dramatically changing inter-relations. Contrary to expectations we find stable correlation patterns with a high similarity across different patients and different frequency bands. This skeleton of spatial correlations may be interpreted as a signature of standing waves of electrical brain activity constituting a dynamical ground state. Such a state could promote the formation of spatiotemporal neuronal assemblies and may be important for the integration of information stemming from different local circuits of the functional brain network.
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Introduction: The re sponse of crop plants ex posed on drought or heat shock is related to de crease in the synthesis of normal proteins, accompanied by increased translation of heat shock proteins (HSPs). Though drought and heat stress have been studied individually, little is known about their combined effect on plants. Methods: The wheat (Triticum aestivum L.) varieties (Katya-tolerant, Sadovo or Mladka-susceptible) were potted in soil. Eight-day-old plants were ex posed to with drawing water for seven days. Heat shock was realized in growth chamber at 40 °C for 6h. A combination of drought and heat shock was per formed by subjecting drought-stressed plants to heat shock treatment. Expression of HSPs in the first leaf of wheat varieties was analyzed by SDS electrophoresis and immunoblotting. Polyclonal antibodies against HSP20, HSP60, HSP110 and mononclonal antibodies against HSP70 were used to distinguish the mentioned HSPs. Results: The leaf relative water content (RWC), which indicated the level of plant dehydration decreased significantly (34 %) under drought stressed conditions The electrolyte leakage of ions (EL), representing the level of the cell membrane stability in creased mark edly (68 %), especially under combination of drought and heat. Maximum EL was ob served in drought susceptible varieties Sadovo and Mladka. Drought and heat shock combination in the wheat plants resulted in the induction of specific HSPs. Conclusions: Our results demonstrate that the response of the wheat plants to a combination of drought and heat stress is different from the response of plants to each of these stresses applied separately. Induction of synergetic effect on HSP expression in case of combination between drought and heat was discussed in the case of two contrasting wheat varieties.
Impact of epinephrine and norepinephrine on two dynamic indices in a porcine hemorrhagic shock model
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Abstract BACKGROUND: Pulse pressure variations (PPVs) and stroke volume variations (SVVs) are dynamic indices for predicting fluid responsiveness in intensive care unit patients. These hemodynamic markers underscore Frank-Starling law by which volume expansion increases cardiac output (CO). The aim of the present study was to evaluate the impact of the administration of catecholamines on PPV, SVV, and inferior vena cava flow (IVCF). METHODS: In this prospective, physiologic, animal study, hemodynamic parameters were measured in deeply sedated and mechanically ventilated pigs. Systemic hemodynamic and pressure-volume loops obtained by inferior vena cava occlusion were recorded. Measurements were collected during two conditions, that is, normovolemia and hypovolemia, generated by blood removal to obtain a mean arterial pressure value lower than 60 mm Hg. At each condition, CO, IVCF, SVV, and PPV were assessed by catheters and flow meters. Data were compared between the conditions normovolemia and hypovolemia before and after intravenous administrations of norepinephrine and epinephrine using a nonparametric Wilcoxon test. RESULTS: Eight pigs were anesthetized, mechanically ventilated, and equipped. Both norepinephrine and epinephrine significantly increased IVCF and decreased PPV and SVV, regardless of volemic conditions (p < 0.05). However, epinephrine was also able to significantly increase CO regardless of volemic conditions. CONCLUSION: The present study demonstrates that intravenous administrations of norepinephrine and epinephrine increase IVCF, whatever the volemic conditions are. The concomitant decreases in PPV and SVV corroborate the fact that catecholamine administration recruits unstressed blood volume. In this regard, understanding a decrease in PPV and SVV values, after catecholamine administration, as an obvious indication of a restored volemia could be an outright misinterpretation.
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BACKGROUND Psoriasis is a chronic inflammatory skin disease and various stress factors mediate inflammation. Heat shock protein (HSP) 90 plays an important role in cell survival; cytokine signaling, such as interleukin-17 receptor signaling; and immune responses. OBJECTIVE We sought to elucidate protein expression and distribution of HSP90 in psoriasis. METHODS HSP90 expression and its cellular source were analyzed on normal-appearing, nonlesional, lesional, and ustekinumab-treated psoriatic skin using immunohistochemistry and double immunofluorescence. RESULTS HSP90α, the inducible isoform of HSP90, was significantly up-regulated in epidermal keratinocytes and mast cells of lesional skin and down-regulated after ustekinumab therapy. LIMITATIONS There was a limited sample size. CONCLUSIONS HSP90 from keratinocytes and mast cells is a key regulator of psoriatic inflammation and HSP90 inhibitors may represent a novel therapeutic approach to the disease.
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The hadronic light-by-light contribution to the anomalous magnetic moment of the muon was recently analyzed in the framework of dispersion theory, providing a systematic formalism where all input quantities are expressed in terms of on-shell form factors and scattering amplitudes that are in principle accessible in experiment. We briefly review the main ideas behind this framework and discuss the various experimental ingredients needed for the evaluation of one- and two-pion intermediate states. In particular, we identify processes that in the absence of data for doubly-virtual pion–photon interactions can help constrain parameters in the dispersive reconstruction of the relevant input quantities, the pion transition form factor and the helicity partial waves for γ⁎γ⁎→ππ.
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The largest uncertainties in the Standard Model calculation of the anomalous magnetic moment of the muon (ɡ − 2)μ come from hadronic contributions. In particular, it can be expected that in a few years the subleading hadronic light-by-light (HLbL) contribution will dominate the theory uncertainty. We present a dispersive description of the HLbL tensor. This new, model-independent approach opens up an avenue towards a data-driven determination of the HLbL contribution to the (ɡ − 2)μ.
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A recently proposed dispersive approach to hadronic light-by-light is described.
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We analyze the pion transition form factor using dispersion theory. We calculate the singly-virtual form factor in the time-like region based on data for the e+e−→3π cross section, generalizing previous studies on ω,ϕ→3π decays and γπ→ππ scattering, and verify our result by comparing to e+e−→π0γ data. We perform the analytic continuation to the space-like region, predicting the poorly-constrained space-like transition form factor below 1GeV, and extract the slope of the form factor at vanishing momentum transfer aπ=(30.7±0.6)×10−3. We derive the dispersive formalism necessary for the extension of these results to the doubly-virtual case, as required for the pion-pole contribution to hadronic light-by-light scattering in the anomalous magnetic moment of the muon.
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BACKGROUND In patients with cardiogenic shock, data on the comparative safety and efficacy of drug-eluting stents (DESs) vs. bare metal stents (BMSs) are lacking. We sought to assess the performance of DESs compared with BMSs among patients with cardiogenic shock undergoing percutaneous coronary intervention (PCI). METHODS Out of 236 patients with acute coronary syndromes complicated by cardiogenic shock, 203 were included in the final analysis. The primary endpoint included death, and the secondary endpoint of major adverse cardiac and cerebrovascular events (MACCEs) included the composite of death, myocardial infarction, any repeat revascularization and stroke. Patients were followed for a minimum of 30 days and up to 4 years. As stent assignment was not random, we performed a propensity score analysis to minimize potential bias. RESULTS Among patients treated with DESs, there was a lower risk of the primary and secondary endpoints compared with BMSs at 30 days (29 vs. 56%, P < 0.001; 34 vs. 58%, P = 0.001, respectively) and during long-term follow-up [hazard ratio 0.43, 95% confidence interval (CI) 0.29-0.65, P < 0.001; hazard ratio 0.49, 95% CI 0.34-0.71, P < 0.001, respectively]. After propensity score adjustment, all-cause mortality was reduced among patients treated with DESs compared with BMSs both at 30 days [adjusted odds ratio (OR) 0.26, 95% CI 0.11-0.62; P = 0.002] and during long-term follow-up (adjusted hazard ratio 0.40, 95% CI 0.22-0.72; P = 0.002). The rate of MACCE was lower among patients treated with DESs compared with those treated with BMSs at 30 days (adjusted OR 0.42, 95% CI 0.19-0.95; P = 0.036). The difference in MACCEs between devices approached significance during long-term follow-up (adjusted hazard ratio 0.60, 95% CI 0.34-1.01; P = 0.052). CONCLUSION DESs appear to be associated with improved clinical outcomes, including a reduction in all-cause mortality compared with BMSs among patients undergoing PCI for cardiogenic shock, possibly because of a pacification of the infarct-related artery by anti-inflammatory drug. The results of this observational study require confirmation in an appropriately powered randomized trial.
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We present a numerical study of electromagnetic wave transport in disordered quasi-one-dimensional waveguides at terahertz frequencies. Finite element method calculations of terahertz wave propagation within LiNbO3 waveguides with randomly arranged air-filled circular scatterers exhibit an onset of Anderson localization at experimentally accessible length scales. Results for the average transmission as a function of waveguide length and scatterer density demonstrate a clear crossover from diffusive to localized transport regime. In addition, we find that transmission fluctuations grow dramatically when crossing into the localized regime. Our numerical results are in good quantitative agreement with theory over a wide range of experimentally accessible parameters both in the diffusive and localized regime opening the path towards experimental observation of terahertz wave localization.
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PURPOSE The molecular chaperone heat shock protein 90 (HSP90) plays an important role in several types of tumors also participating in the modulation of the activity of receptor tyrosine kinases activity such as members of the Her family. We evaluated the significance of HSP90 and Her2 expression in colon cancer. METHODS HSP90 and Her2 expression was determined by immunohistochemistry and by fluorescence in situ hybridization (FISH) on 355 primary resected colon carcinomas. Results were correlated with pathologic features (Union for International Cancer Control (UICC) pTNM category, tumor localisation, tumor differentiation), additional molecular genetic characteristics (BRAF, KRAS mutational status, mismatch repair genes (MMR)), and survival. RESULTS HSP90 immunoreactivity was observed in various degrees. Fifty-one cases (14 %) were positive for Her2 (score 2+ and 3+) with 16/43 cases with Her2 2+ staining pattern showing amplification of Her2 determined by FISH. There was a significant correlation between high HSP90 expression and Her2 overexpression (p = 0.011). High HSP90 expression was associated with earlier tumor stages (p = 0.019), absence of lymph node (p = 0.006), and absence of distant metastases (p = 0.001). Patients with high tumoral HSP90 levels had a better survival (p = 0.032), but this was not independent from other prognostic relevant pathologic parameters. Her2 expression was not associated with any of the investigated histopathological, molecular, or clinical parameters. CONCLUSIONS High HSP90 levels are reflecting lower malignant potential in colon cancer. Her2 positivity can be observed in a small number of cases. Targeting HSP90 and/or Her2 may be an alternative therapeutic approach in colon cancer in a subset of patients.