173 research outputs found
Modelling of heat transfer process in condensing unit with titanium alloy tubes
One of the most important units of heat transfer equipment of a nuclear power plant is the condenser. Currently, at the nuclear stations of concern “Rosenergoatom” work is actively underway to replace the tubes of copper containing alloys to various steels or titanium alloys. Also, active work is underway on modernization of heat-exchange equipment of operating units. It is necessary to make the modelling of the parameters of condenser, to ensure that after the upgrade, the unit will continue operating normally. For this purpose, was created the model of module of tube bundle of condenser unit of K-33160 with tubes of titanium alloy. The modelling process is based on the equation of heat balance. In this work were modelled condenser of NPP of K-33160 with WWER-1000 reactor and the tubes of a titanium alloy VT0-1. The calculation was carried out for three presented methods and the error was less than 2%
Continuous monitoring of blood clotting during hemodialysis, and cardiopulmonary bypass „MonHem”
Dużym problemem u chorych leczonych hemodializami bądź krążeniem pozaustrojowym jest właściwa optymalizacja krzepliwości krwi przy stosowanej heparynizacji (czas aPTT). Krzepliwość ta w krótkim czasie może znacznie się zmienić w trakcie zabiegów, a jej dokładna natychmiastowa ocena jest w wielu sytuacjach bardzo utrudniona lub wręcz niemożliwa. Nadmierna heparynizacja u takich chorych może być zarówno niebezpieczna (możliwość krwawień), jak i niewystarczająca (niebezpieczeństwo wykrzepiania krwi w drenach i stosowanej aparaturze). Naprzeciw tym problemom wychodzi polsko-niemiecki projekt badawczy „MonHem” składający się z dwóch podstawowych części: pierwsza obejmuje opracowanie koncepcji i jej sprawdzenie na modelu doświadczalnym, druga natomiast polega na konstrukcji prototypów urządzeń mogących służyć do dynamicznej oceny krzepliwości krwi w czasie zabiegów, popartej doświadczeniami na zwierzętach. Autorzy wierzą, że w wypadku pomyślnej realizacji tego projektu poprawi się bezpieczeństwo pacjentów leczonych tymi metodami.The aim of this study was to create a design and then construction of prototypes allowing for dynamic assessment of coagulation function by continuous monitoring of the activated partial tromboplastin time (a-PTT), or blood clotting time in patients treated with hemodialysis or connected to cardiopulmonary bypass. We believe that the introduction of such a diagnostic method in the case of the successful implementation enhanced safety to patients treated with those methods, by reducing the risk of complications associated with an inappropriate heparinisation these patients in the form of a blood clot in the course of treatment due to an insufficient supply of heparin, or excessive or unexpected bleeding using an overdose of drug
Time course of redox potential and antioxidant capacity in patients undergoing cardiac surgery
Impella and IABP for high-risk PCI: a systematic review and meta-analysis
Aims: A systematic literature review (SLR) and meta-analysis was undertaken to compare health outcomes associated with the use of Impella and intra-aortic balloon pump (IABP) in patients undergoing high-risk percutaneous coronary intervention (HR PCI). Methods and results: A SLR of published randomised and non-randomised studies from Sep 1999-2019 (20 years) was undertaken through a search of MEDLINE®, Web of Science, Cochrane Library, and Scopus. Forward and backward citation searching was conducted using Google Scholar and supplemented with a search of the grey literature. For studies which met the inclusion criteria, data extracted included respondent characteristics, study design, and the reporting of mortality, myocardial infarction, complication rates, and other clinical outcomes. A comparison of clinical outcomes was synthesized using a meta-analysis and a random-effects model was fitted to account for heterogeneity between studies. Small study effect, including publication bias, was tested using funnel plots and Egger's test. Meta-analyses of patient subgroups were also conducted where data permitted. Of 638 titles and abstracts screened, 22 studies met the study inclusion criteria. Studies tended to report superior health outcomes for patients who received Impella compared to IABP in terms of lower mortality, major bleeding, vascular complications, revascularisation, stroke/transient ischaemic attack, renal complications, and major adverse cardiovascular events (MACE)/major adverse cardiovascular and cerebrovascular events (MACCE). Although funnel plots were not always found to be symmetrical, no evidence of publication bias (with the exception of the IABP pooled MACE/MACCE (p=0.033) outcome) was found with the Egger's test (p>0.05). Conclusions: The results of our SLR and meta-analysis indicate that Impella is associated with superior health outcomes when compared to IABP in terms of mortality, major bleeding, vascular complications, revascularisation, stroke/ transient ischaemic attack, renal complications, and MACE/MACCE. Further research is needed to explore the conclusions regarding the presence of publication bias with the IABP pooled MACE/MACCE outcome. Moreover, further studies and/ or real-world data (RWD) are needed to confirm and identify the optimal approach for patients undergoing HR PCI in clinical practice. This will enable the aforementioned patients to gain maximal health status by using available resources
Error estimation in multitemporal InSAR deformation time series, with application to Lanzarote, Canary Islands
Interferometric Synthetic Aperture Radar (InSAR) is a reliable technique for measuring crustal deformation. However, despite its long application in geophysical problems, its error estimation has been largely overlooked. Currently, the largest problem with InSAR is still the atmospheric propagation errors, which is why multitemporal interferometric techniques have been successfully developed using a series of interferograms. However, none of the standard multitemporal interferometric techniques, namely PS or SB (Persistent Scatterers and Small Baselines, respectively) provide an estimate of their precision. Here, we present a method to compute reliable estimates of the precision of the deformation time series. We implement it for the SB multitemporal interferometric technique (a favorable technique for natural terrains, the most usual target of geophysical applications). We describe the method that uses a properly weighted scheme that allows us to compute estimates for all interferogram pixels, enhanced by a Montecarlo resampling technique that properly propagates the interferogram errors (variance-covariances) into the unknown parameters (estimated errors for the displacements). We apply the multitemporal error estimation method to Lanzarote Island (Canary Islands), where no active magmatic activity has been reported in the last decades. We detect deformation around Timanfaya volcano (lengthening of line-of-sight ∼ subsidence), where the last eruption in 1730–1736 occurred. Deformation closely follows the surface temperature anomalies indicating that magma crystallization (cooling and contraction) of the 300-year shallow magmatic body under Timanfaya volcano is still ongoing.Peer reviewe
Erratum to: Does percutaneous dilatational tracheostomy increase the incidence of sternal wound infection - a single center retrospective of 4100 cases
Speckle tracking echography allows sonographic assessment of diaphragmatic loading
Introduction: Assessment of diaphragm function should ideally be assessed using magnetic twitch pressure or esophageal and gastric balloons. Conventional sonographic techniques as thickness and fractional thickening (FT), only provide limited insight in diaphragm function. Speckle tracking echocardiography allows reliable quantification of muscle function by tracking of grey patterns and their motion; strain as parameter of muscle deformation and strain rate as deformation velocity. Aim: To investigate whether speckle tracking can quantify loading of the diaphragm, superior to FT. Methods: 13 healthy volunteers underwent an inspiratory loading protocol with recording of transdiaphragmatic pressure (Pdi) and diaphragm electromyography (EMGdi). Inspiratory loading of 0 to 30% of maximal inspiratory pressure was applied in random order for 5 minutes per applied load. Diaphragmatic sonography was performed using a 2-4 MHz linear phased array transducer positioned at the right-lateral thoracic wall in the anterior axillary line longitudinal to the body axis. Ultrasound recordings of the diaphragm were made at the marked location during 10 seconds. Results: Increased inspiratory loading increased Pdi and EMGdi. Sonographic markers of contractility increased with incremental loading. Pdi correlated with strain (r=0.75; p=0.000) and strain rate (r=0.77; p=0.000). Contrarily, FT was not correlated with Pdi. Conclusion: Speckle tracking of the diaphragm can detect changes in diaphragmatic loading up to 30% of maximal inspiratory pressure. It might be a valuable tool to detect changes in loading in specific patient categories, including patients with acute respiratory failure and ventilated ICU patients
Exogenous Administration of Recombinant MIF at Physiological Concentrations Failed to Attenuate Infarct Size in a Langendorff Perfused Isolated Mouse Heart Model
Benefits of ultra-fast-track anesthesia in left ventricular assist device implantation: a retrospective, propensity score matched cohort study of a four-year single center experience
Cardiomyocyte Specific Ablation of p53 Is Not Sufficient to Block Doxorubicin Induced Cardiac Fibrosis and Associated Cytoskeletal Changes
Doxorubicin (Dox) is an anthracycline used to effectively treat several forms of cancer. Unfortunately, the use of Dox is limited due to its association with cardiovascular complications which are manifested as acute and chronic cardiotoxicity. The pathophysiological mechanism of Dox induced cardiotoxicity appears to involve increased expression of the tumor suppressor protein p53 in cardiomyocytes, followed by cellular apoptosis. It is not known whether downregulation of p53 expression in cardiomyocytes would result in decreased rates of myocardial fibrosis which occurs in response to cardiomyocyte loss. Further, it is not known whether Dox can induce perivascular necrosis and associated fibrosis in the heart. In this study we measured the effects of acute Dox treatment on myocardial and perivascular apoptosis and fibrosis in a conditional knockout (CKO) mouse model system which harbours inactive p53 alleles specifically in cardiomyocytes. CKO mice treated with a single dose of Dox (20 mg/kg), did not display lower levels of myocardial apoptosis or reactive oxygen and nitrogen species (ROS/RNS) compared to control mice with intact p53 alleles. Interestingly, CKO mice also displayed higher levels of interstitial and perivascular fibrosis compared to controls 3 or 7 days after Dox treatment. Additionally, the decrease in levels of the microtubule protein α-tubulin, which occurs in response to Dox treatment, was not prevented in CKO mice. Overall, these results indicate that selective loss of p53 in cardiomyocytes is not sufficient to prevent Dox induced myocardial ROS/RNS generation, apoptosis, interstitial fibrosis and perivascular fibrosis. Further, these results support a role for p53 independent apoptotic pathways leading to Dox induced myocardial damage and highlight the importance of vascular lesions in Dox induced cardiotoxicity
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