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1.
BMC Cardiovasc Disord ; 24(1): 580, 2024 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-39434009

RESUMO

BACKGROUND: Liver dysfunction is a known risk factor in the cardiovascular field. It specifically increases perioperative risk in patients undergoing coronary bypass surgery. Since percutaneous coronary intervention (PCI) is the much less invasive procedure for the treatment of coronary artery disease, we aimed to assess the relationship of liver dysfunction with outcomes in patients undergoing PCI. METHODS: Three libraries were searched (MEDLINE, Web of Science and The Cochrane Library). We performed a meta-analysis of all studies in patients who underwent PCI that provided information on the presence or absence of liver dysfunction. Primary outcome was short-term mortality. Secondary outcomes were major adverse cardio- and cerebrovascular events (MACCE), bleeding and acute kidney injury. Random-effects model was applied. RESULTS: Five studies were selected and the data from 10,710,317 patients were included in the final analysis. In comparison with the absence of liver dysfunction, patients with liver dysfunction were associated with higher short-term mortality (OR 2.97, 95%CI 1.23-7.18, p = 0.02), higher MACCE (OR 1.42, 95%CI 1.08-1.87, p = 0.01), and higher bleeding (OR 2.23, 95%CI 1.65-3.00, p < 0.01). There was no significant difference regarding acute kidney injury (OR 1.20, 95%CI 0.50-2.87, p = 0.69). CONCLUSIONS: The analysis suggests that liver dysfunction in patients undergoing PCI is independently associated with higher risk of short-term mortality and increased occurrence of MACCE and bleeding. However, there appears to be no association to acute kidney injury.


Assuntos
Doença da Artéria Coronariana , Hepatopatias , Intervenção Coronária Percutânea , Humanos , Intervenção Coronária Percutânea/efeitos adversos , Intervenção Coronária Percutânea/mortalidade , Fatores de Risco , Doença da Artéria Coronariana/mortalidade , Doença da Artéria Coronariana/terapia , Doença da Artéria Coronariana/fisiopatologia , Resultado do Tratamento , Medição de Risco , Hepatopatias/mortalidade , Hepatopatias/diagnóstico , Hepatopatias/fisiopatologia , Masculino , Fatores de Tempo , Feminino , Pessoa de Meia-Idade , Idoso , Injúria Renal Aguda/mortalidade , Injúria Renal Aguda/diagnóstico , Injúria Renal Aguda/etiologia , Injúria Renal Aguda/fisiopatologia , Hemorragia/mortalidade
2.
Artigo em Inglês | MEDLINE | ID: mdl-38781984

RESUMO

BACKGROUND: This study aimed to assess the influence of the model of end-stage liver disease without International Normalized Ratio (INR) (MELD-XI) score on outcomes after elective coronary artery bypass surgery (CABG) without (Off-Pump) or with (On-Pump) cardiopulmonary bypass. METHODS: We calculated MELD-XI (5.11 × ln serum bilirubin + 11.76 × ln serum creatinine in + 9.44) for 3,535 consecutive patients having undergone elective CABG between 2009 and 2020. A MELD-XI threshold was determined using the Youden Index based on receiver operating characteristics. Propensity score matching and logistic regression was performed to identify risk factors for inhospital mortality and Major Adverse Cardiac and Cerebrovascular Event (MACCE). RESULTS: Patients were 68 ± 10 years old (76% male). Average MELD-XI was 10.9 ± 3.25. The MELD-XI threshold was 11. Patients below this threshold had somewhat lower EuroSCORE II than those above (3.5 ± 4 vs. 4.1 ± 4.7, p < 0.01), but mortality was almost four times higher above the threshold (below 1.5% vs. above 6.2%, p < 0.001). Two-thirds of patients received Off-Pump CABG. There was a trend towards higher risk in Off-Pump patients. Mortality was numerically but not statistically different to On-Pump below the MELD XI threshold (1.3 vs. 2.2%, p = 0.34) and was significantly lower above the threshold (4.9 vs. 8.9%, p < 0.02). Off-Pump above the threshold was also associated with less low-output syndrome and fewer strokes. Equalizing baseline differences by propensity matching verified the significant mortality difference above the threshold. Multivariable regression analysis revealed MELD-XI, On-Pump, atrial fibrillation, and the De Ritis quotient (Aspartate aminotransferase (ASAT)/Alanine Aminotransferase (ALAT)) as independent predictors of mortality. CONCLUSION: Elective CABG patients with elevated MELD-XI scores are at increased risk for perioperative mortality and morbidity. This risk can be significantly mitigated by performing CABG Off-Pump.

3.
Langmuir ; 39(38): 13521-13533, 2023 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-37697862

RESUMO

Measurements of gas mixture adsorption equilibria at high pressures are important for assessing actual adsorbent selectivities but are often out of reach, given the challenging nature of the required experiments. Here, we report a high-pressure gravimetric binary gas adsorption equilibrium measurement system based on simultaneous gas density and mixture adsorption measurements in a single gas cell coupled to a magnetic-suspension balance. Compared to traditional techniques which rely on analytical measurements of gas composition, this approach does not require any sampling. Adsorption measurements of two gas mixtures (0.500 N2 + 0.500 CH4 and 0.400 N2 + 0.600 CO2, mole fraction) on a commercially available molecular sieve (NaY, sodium molecular sieve type Y) were carried out in the temperature range 282 to 325 K with a pressure up to 10 MPa. A prediction method for the gas mixture adsorption equilibria in a closed system using the ideal adsorbed solution theory (IAST) model was used to compare the experimental results. For binary mixtures of components with similar adsorption capacities (here N2 and CH4), the system can measure the adsorption equilibria at pressures higher than 1.0 MPa and the result agrees well with the IAST model prediction. For two gases with very different adsorption capacities, the uncertainty in the adsorption equilibrium measurement is much larger. The dominant uncertainty source is the gas density measurement, whose uncertainty could potentially be cut to half if the current titanium sinker is replaced with a sinker made of single-crystal silicon and with a larger volume.

4.
Eur J Pediatr ; 181(4): 1585-1596, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34950979

RESUMO

Expert recommendations for the management of tumor surveillance in children with a variety of cancer predisposition syndromes (CPS) are available. We aimed (1) at identifying and characterizing children who are affected by a CPS and (2) at comparing current practice and consensus recommendations of the American Association for Cancer Research workshop in 2016. We performed a database search in the hospital information system of the University Children's Hospital for CPS in children, adolescents, and young adults and complemented this by review of electronic patients' charts. Between January 1, 2017, and December 3, 2019, 272 patients with 41 different CPS entities were identified in 20 departments (144 [52.9%] male, 128 [47.1%] female, median age 9.1 years, range, 0.4-27.8). Three (1.1%) patients died of non-malignancy-associated complications of the CPS; 49 (18.0%) patients were diagnosed with malignancy and received regular follow-up. For 209 (95.0%) of the remaining 220 patients, surveillance recommendations were available: 30/220 (13.6%) patients received CPS consultations according to existing consensus recommendations, 22/220 (10.0%) institutional surveillance approaches were not complying with recommendations, 84/220 (38.2%) patients were seen for other reasons, and 84/220 (38.2%) were not routinely cared for. Adherence to recommendations differed extensively among CPS entities. CONCLUSION: The spectrum of CPS patients at our tertiary-care children's hospital is manifold. For most patients, awareness of cancer risk has to be enhanced and current practice needs to be adapted to consensus recommendations. Offering specialized CPS consultations and establishing education programs for patients, relatives, and physicians may increase adherence to recommendations. WHAT IS KNOWN: • A wide spectrum of rare syndromes manifesting in childhood is associated with an increased cancer risk. • For many of these syndromes, expert recommendations for management and tumor surveillance are available, although based on limited evidence. WHAT IS NEW: • Evaluating current practice, our data attest significant shortcomings in tumor surveillance of children and adolescents with CPS even in a tertiary-care children's hospital. • We clearly advocate a systematic and consistent integration of tumor surveillance into daily practice.


Assuntos
Neoplasias , Adolescente , Criança , Feminino , Predisposição Genética para Doença , Hospitais , Humanos , Masculino , Neoplasias/diagnóstico , Neoplasias/epidemiologia , Estudos Retrospectivos , Síndrome , Estados Unidos , Adulto Jovem
5.
Chemphyschem ; 19(6): 784-792, 2018 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-29267986

RESUMO

Accurate measurements of carbon monoxide's electrical properties were carried out at high pressure for the first time enabling stringent comparisons with theoretical values calculated ab initio. Dielectric permittivity measurements were conducted utilising a microwave re-entrant cavity resonator over the temperature range from (255 to 313) K and at pressures up to 8 MPa with a relative combined expanded uncertainty (k=2) less than or equal to 52 ppm. The new data enable carbon monoxide's molar polarizability to be correlated within 0.5 %, significantly improving upon existing literature data, which have a relative scatter of about 10 %. The measured molecular polarizability and electric dipole moment of carbon monoxide were determined to be 2.176×10-40  C2 m2 J-1 and 0.107 D. Literature values from ab initio calculations for these properties are within 0.28 % and 3.9 %, respectively, of the measured quantities. Moreover, our measurement of the electric dipole moment at finite temperature agrees within 2.2 % with the value derived from accurate spectroscopic measurements for the ground rovibrational state. The second dielectric virial coefficient of carbon monoxide was determined experimentally for the first time to be bϵ =(1.015±0.044) cm3 mol-1 , which compares reasonably with ab initio estimates.

6.
Int J Thermophys ; 45(5): 72, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38645609

RESUMO

A high-pressure vibrating tube densimeter, specified by the manufacturer for temperatures from (263 to 473) K at pressures up to 140 MPa, was tested at temperatures down to 100 K and from vacuum to pressures up to 10 MPa. To verify the functionality and overall performance under these conditions, the densimeter was calibrated with measurements under vacuum as well as methane and propane as reference fluids. The calibration range is T = (120 to 200) K at pressures from (2.0 to 10.0) MPa. To evaluate the recorded data, two established calibration models were used to describe the dependence of the densimeter's oscillation period on the investigated reference fluids' temperature, pressure, and density. The experiments showed that the vibrating tube densimeter is operational even at temperatures down to 100 K, but exhibits a shift of its vacuum resonance when subjected to thermal cycling at temperatures below 180 K. Accordingly, the calibration models were modified with respect to how the vacuum resonance is considered. Then, the determined calibration parameters reproduce the densities of the reference fluids within ± 0.10 kg·m-3 for the calibration model that performed better for the present study. Measurements on pure ethane and argon validate the calibration of the densimeter. Here, the densities are within (- 0.47 to 0.16) kg·m-3 of values calculated with the respective reference equation of state. The estimated combined expanded uncertainty (k = 2) in density for the validation measurements ranges from (0.52 to 1.13) kg·m-3 or is less than 0.1 % for liquid densities. Supplementary Information: The online version of this article (10.1007/s10765-024-03357-9) contains supplementary material, which is available to authorized users.

7.
Adv Sci (Weinh) ; 9(9): e2105477, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35072350

RESUMO

Functionalized porous materials could play a key role in improving the efficiency of gas separation processes as required by applications such as carbon capture and storage (CCS) and across the hydrogen value chain. Due to the large number of different functionalizations, new experimental approaches are needed to determine if an adsorbent is suitable for a specific separation task. Here, it is shown for the first time that Raman spectroscopy is an efficient tool to characterize the adsorption capacity and selectivity of translucent functionalized porous materials at high pressures, whereby translucence is the precondition to study mass transport inside of a material. As a proof of function, the performance of three silica ionogels to separate an equimolar (hydrogen + carbon dioxide) gas mixture is determined by both accurate gravimetric sorption measurements and Raman spectroscopy, with the observed consistency establishing the latter as a novel measurement technique for the determination of adsorption capacity. These results encourage the use of the spectroscopic approach as a rapid screening method for translucent porous materials, particularly since only very small amounts of sample are required.

8.
Thorac Cardiovasc Surg Rep ; 11(1): e17-e19, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35223366

RESUMO

We report the rare case of a 51-year-old patient with a 15 cm mediastinal rhabdomyosarcoma with blood supply from the left anterior descending artery presenting as a large mass including the pericardium with extensive contact to the epicardium compressing heart and left lung. The tumor was successfully removed through median sternotomy, blunt dissection from the heart and the left lung, resection of the infiltrated pericardium, and ligation of the tumor-feeding vessels using off-pump stabilizers. Histopathological examination revealed a spindle cell rhabdomyosarcoma with R0 resection. The postoperative course was uneventful, and patient is feeling well at 3-month follow-up.

9.
J Pediatr ; 157(2): 240-244.e1, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20400104

RESUMO

OBJECTIVE: To test the hypothesis that compared with controls, children with inflammatory bowel disease (IBD) exhibit differences in the relationships between gut microbiota and disease activity. STUDY DESIGN: Children and adolescents (n = 69; median age, 14 years) with IBD and 25 healthy controls (median age, 14 years) were recruited for the study. The disease activity was determined according to the Pediatric Ulcerative Colitis Activity Index or the Pediatric Crohn Disease Activity Index. Cell counts of 9 bacterial groups and species in the fecal microbiota were monitored by real-time polymerase chain reaction analysis. RESULTS: Although no major changes were observed in patients with ulcerative colitis, except for a decrease in bifidobacteria in the active state of IBD, children with active and inactive Crohn's disease (CD) had lower numbers of Faecalibacterium prausnitzii and bifidobacteria (P <.05), and patients with active CD had higher numbers of Escherichia coli (P <.05). CONCLUSIONS: The microbiota in children with CD is characterized by decreased numbers of F praunsitzii and increased numbers of E coli.


Assuntos
Colite Ulcerativa/microbiologia , Doença de Crohn/microbiologia , Doenças Inflamatórias Intestinais/microbiologia , Intestinos/microbiologia , Adolescente , Adulto , Estudos de Casos e Controles , Criança , Pré-Escolar , DNA Bacteriano/metabolismo , Escherichia coli/metabolismo , Humanos , Hibridização in Situ Fluorescente , Lactente , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Ruminococcus/metabolismo
10.
J Pediatr Gastroenterol Nutr ; 51(1): 103-5, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20453671

RESUMO

OBJECTIVE: : Development of the mucosal immune system is essential for controlling antigenic response. External factors are known to influence the immune system, such as breast-feeding or the mode of delivery. The aim of the present study was to investigate maturation of the enteric immune system. PATIENTS AND METHODS: : In stool samples of 59 preterm and term-born infants we measured the concentration of human beta-defensin 2 (HBD 2), an endogenous antimicrobial peptide, and tumor necrosis factor-alpha (TNF-alpha), a cytokine playing a central role in mucosal inflammation, by enzyme-linked immunosorbent assay. RESULTS: : Mode of delivery as well as nutrition (breast-feeding or formula) had no influence on the fecal concentration of HBD-2 or TNF-alpha, but there was a significant increase in the concentration of HBD-2 in correlation with gestational age. TNF-alpha showed no change in concentration. CONCLUSIONS: : Low fecal HBD-2 may be a risk factor in preterm infants to develop neonatal enteric disease, such as necrotizing enterocolitis.


Assuntos
Colo/imunologia , Fezes/química , Idade Gestacional , Recém-Nascido , Fator de Necrose Tumoral alfa/análise , beta-Defensinas/análise , Aleitamento Materno , Cesárea , Feminino , Humanos , Sistema Imunitário/crescimento & desenvolvimento , Fórmulas Infantis , Recém-Nascido Prematuro , Masculino , Gravidez
11.
Adsorption (Boston) ; 262020 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-39380578

RESUMO

A commercial gravimetric sorption analyzer, which is based on a magnetic-suspension balance, was significantly improved to reduce the uncertainty in adsorption measurements. In a previous paper, we investigated the force-transmission error (FTE) of the instrument's magnetic-suspension coupling, and we analysed the uncertainty of the density measurement. In the present paper, equations for the determination of the adsorption on porous and quasi non-porous materials are provided, where the FTE is taken into account, and a detailed uncertainty analysis is presented. The uncertainty analysis was applied to both the improved measurement system and a typical commercial gravimetric sorption analyzer. Adsorption test measurements were conducted with carbon dioxide along the T = 283 K isotherm at pressures up to the dew-point pressure using both a porous material (zeolite 13X) and a quasi non-porous material (solid metallic sinkers). The major uncertainty contributions for adsorption on the porous material were the mass and volume of the adsorbent sample and the assumption of the density of the adsorbed fluid; for the quasi non-porous material, the main contributions were the weighing values of the balance, the density of the investigated fluid in the gas phase, and the volume of the non-porous material. The influence of the FTE on the adsorption on the porous material was approximately 0.002 mmol·g-1, which was negligibly small; but the influence of the FTE was significant in the case of the quasi non-porous material, i.e., approximately 0.7 mmol·m-2 or about 22% of the adsorption capacity with the highest adsorption observed in this work (near the dew-point pressure). This indicates that the influence of the FTE increases significantly with decreasing adsorption capacity of the adsorbent sample.

12.
ACS Omega ; 5(19): 10704-10714, 2020 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-32455189

RESUMO

The doping of SiO2 and Fe2O3 into hydrochars that were produced by the hydrothermal carbonization of cellulose was studied with respect to its impact on the resulting surface characteristics and sorption behavior of CO2, CH4, and O2. During pyrolysis, the structural order of the Fe-doped char changed, as the fraction of highly ordered domains increased, which was not observed for the undoped and Si-doped chars. The Si doping had no apparent influence on the oxidation temperature of the hydrochar in contrast to the Fe-doped char where the oxidation temperature was reduced because of the catalytic effect of Fe. Both dopants reduced the micro-, meso- and macroporous surface areas of the chars, although the Fe-doped chars had larger meso- and macroporosity than the Si-doped char. However, the increased degree in the structural order of the carbon matrix of the Fe-doped char reduced its microporosity relative to the Si-doped char. The adsorption of CO2 and CH4 on the chars at temperatures between 273.15 and 423.15 K and at pressures up to 115 kPa was slightly inhibited by the Si doping but strongly suppressed by the Fe doping. For O2, however, the Si doping promoted the observed adsorption capacity, while Fe doping also showed an inhibiting effect.

13.
Sci Rep ; 7(1): 6185, 2017 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-28733575

RESUMO

Phase equilibria of fluid mixtures are important in numerous industrial applications and are, thus, a major focus of thermophysical property research. Improved data, particularly along the dew line, are needed to improve model predictions. Here we present experimental results utilizing highly accurate densimetry to quantify the effects of sorption and capillary condensation, which exert a distorting influence on measured properties near the dew line. We investigate the (pressure, density, temperature, composition) behaviour of binary (CH4 + C3H8) and (Ar + CO2) mixtures over the temperature range from (248.15 to 273.15) K starting at low pressures and increasing in pressure towards the dew point along isotherms. Three distinct regions are observed: (1) minor sorption effects in micropores at low pressures; (2) capillary condensation followed by wetting in macro-scale surface scratches beginning approximately 2% below the dew-point pressure; (3) bulk condensation. We hypothesize that the true dew point lies within the second region.

14.
Meas Sci Technol ; 28(12)2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-33404206

RESUMO

For the determination of dew-point densities and pressures of fluid mixtures, a new densimeter has been developed. The new apparatus is based on the well-established two-sinker density measurement principle with the additional capability of quantifying sorption effects. In the vicinity of the dew line, such effects cause a change in composition of the gas mixture under study, which can significantly distort accurate density measurements. The new experimental technique enables the accurate measurement of dew-point densities and pressures and the quantification of sorption effects at the same time.

15.
Eur J Cardiothorac Surg ; 29(2): 210-5, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16386921

RESUMO

OBJECTIVE: Primary graft dysfunction caused by ischemia-reperfusion injury is one of the most frequent causes of early morbidity and death after lung transplantation. We hypothesized that the perioperative management with aprotinin decreases the incidence of allograft reperfusion injury and dysfunction after clinical lung transplantation. METHODS: Lung transplant databases of two transplant centers were used to investigate the incidence of severe post-transplant reperfusion injury (PTRI). We examined data of 142 patients who underwent either single lung (81) or bilateral sequential lung (61) transplantation for COPD, idiopathic pulmonary fibrosis, cystic fibrosis, and miscellaneous lung disorders between 1997 and 2000. Thirty patients were excluded due to heart-lung transplantation or lung transplantation for Eisenmenger's disease, re-transplantation, rejection, or deviation from the standardized triple immunosuppression protocol. The data of remaining 112 patients (control group, 64% single lung, 36% sequential bilateral lung transplants) were compared to the prospectively collected data of 59 lung transplant patients over the last 5 years. All of these 59 patients were managed perioperatively with aprotinin infusion. In addition, Euro-Collins-aprotinin procurement solution (Apt-EC group) was used for 50 donor lungs (58% single lung, 42% sequential bilateral lung transplants). Aprotinin in combination with low-potassium dextran (LPD) flush solution (Apt-LPD group) was used for the procurement of 34 lungs (59% single lung, 41% sequential bilateral lung transplants). The International Society of Heart and Lung Transplantation (ISHLT) grade III injury score was used for the diagnosis of severe PTRI, which is based on a PaO(2)-FIO(2) ratio of less than 200 mmHg. RESULTS: Severe reperfusion injury grade III was observed in 18% of the control group. ECMO support was required in 25% of these patients. The associated mortality rate was 40%. Correlating factors for PTRI were donor age greater than 35 years (45%, p=0.01, mean age 38+/-8) and recipient pulmonary artery systolic pressure greater than 60 mmHg (48%, p<0.05). Lung graft ischemic times (231+/-14 min) and intraoperative techniques (cardiopulmonary bypass in 12%) were not associated with negative outcomes. Despite longer ischemic times (258+/-36 min and 317+/-85 min, respectively) and older donors (42+/-12 years and 46+/-12 years, respectively) in the aprotinin patient groups (Apt-EC and Apt-LPD group), the incidence of PTRI was markedly lower (6% and 9%, respectively). There was no mortality in the Apt-EC group and one patient died in the Apt-LPD group due to PTRI-induced graft failure. CONCLUSIONS: Severe PTRI increased short-term morbidity and mortality. The incidence of reperfusion injury was not dependent upon the duration of donor organ ischemia. The use of aprotinin in the perioperative patient management in lung transplantation had strong beneficial effects on the patient outcomes and decreased the incidence of post-transplant ischemia-reperfusion injury significantly.


Assuntos
Aprotinina/uso terapêutico , Pneumopatias/cirurgia , Transplante de Pulmão/métodos , Pulmão/irrigação sanguínea , Traumatismo por Reperfusão/prevenção & controle , Inibidores de Serina Proteinase/uso terapêutico , Adulto , Análise de Variância , Ponte Cardiopulmonar , Estudos de Casos e Controles , Feminino , Sobrevivência de Enxerto , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Transplante Homólogo
16.
J Chem Thermodyn ; 99: 105-115, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-28867827

RESUMO

We explore a novel method for determining the dew-point density and dew-point pressure of fluid mixtures and compare it to traditional methods. The (p, ρ, T, x) behavior of three (methane + propane) mixtures was investigated with a two-sinker magnetic suspension densimeter over the temperature range of (248.15 to 293.15) K; the measurements extended from low pressures into the two-phase region. The compositions of the gravimetrically prepared mixtures were (0.74977, 0.50688, and 0.26579) mole fraction methane. We analyzed isothermal data by: (1) a "traditional" analysis of the intersection of a virial fit of the (p vs. ρ) data in the single-phase region with a linear fit of the data in the two-phase region; and (2) an analysis of the adsorbed mass on the sinker surfaces. We compared these to a traditional isochoric experiment. We conclude that the "adsorbed mass" analysis of an isothermal experiment provides an accurate determination of the dew-point temperature, pressure, and density. However, a two-sinker densimeter is required.

18.
J Chem Thermodyn ; 99: 54-64, 2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27458321

RESUMO

The speed of sound of two (argon + carbon dioxide) mixtures was measured over the temperature range from (275 to 500) K with pressures up to 8 MPa utilizing a spherical acoustic resonator. The compositions of the gravimetrically prepared mixtures were (0.50104 and 0.74981) mole fraction carbon dioxide. The vibrational relaxation of pure carbon dioxide led to high sound absorption, which significantly impeded the sound-speed measurements on carbon dioxide and its mixtures; pre-condensation may have also affected the results for some measurements near the dew line. Thus, in contrast to the standard operating procedure for speed-of-sound measurements with a spherical resonator, non-radial resonances at lower frequencies were taken into account. Still, the data show a comparatively large scatter, and the usual repeatability of this general type of instrument could not be realized with the present measurements. Nonetheless, the average relative combined expanded uncertainty (k = 2) in speed of sound ranged from (0.042 to 0.056)% for both mixtures, with individual state-point uncertainties increasing to 0.1%. These uncertainties are adequate for our intended purpose of evaluating thermodynamic models. The results are compared to a Helmholtz energy equation of state for carbon capture and storage applications; relative deviations of (-0.64 to 0.08)% for the (0.49896 argon + 0.50104 carbon dioxide) mixture, and of (-1.52 to 0.77)% for the (0.25019 argon + 0.74981 carbon dioxide) mixture were observed.

19.
Eur J Cardiothorac Surg ; 50(4): 713-720, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26935407

RESUMO

OBJECTIVES: Aortic valve replacement (AVR) via minimally invasive surgery (MIS) may provide clinical benefits in patients with aortic valve disease. A new class of bioprosthetic valves that enable rapid deployment AVR (RDAVR) may facilitate MIS. We here report the 1-year results of a randomized, multicentre trial comparing the outcomes for MIS-RDAVR with those for conventional AVR via full sternotomy (FS) with a commercially available stented aortic bioprosthesis. METHODS: A total of 100 patients with aortic stenosis were enrolled in a prospective, multicentre, randomized comparison trial (CADENCE-MIS). Key exclusion criteria included AVR requiring concomitant procedures, ejection fraction of <25% and recent myocardial infarction or stroke. Patients were randomized to undergo MIS-RDAVR via upper hemisternotomy (EDWARDS INTUITY) or AVR via FS with a commercially available stented valve. Procedural, early and late clinical outcomes were assessed for both groups. Haemodynamic performance was evaluated by an echocardiography CoreLaboratory. RESULTS: Technical success was achieved in 94% of MIS-RDAVR patients. MIS-RDAVR was associated with significantly reduced cross-clamp times compared with FS (41.3 ± 20.3 vs 54.0 ± 20.3 min, P < 0.001). Clinical and functional outcomes were similar at 30 days and 1 year postoperatively for both groups. While both groups received a similarly sized implanted valve (22.9 ± 2.1 mm MIS-RDAVR vs 23.0 ± 2.1 mm FS-AVR; P = 0.91), MIS-RDAVR patients had significantly lower peak gradients 1 year postoperatively (16.9 ± 5.3 vs 21.9 ± 8.6 mmHg; P = 0.033) and a trend towards lower mean gradients (9.1 ± 2.9 vs 11.5 ± 4.3 mmHg; P = 0.082). In addition, MIS-RDAVR patients had a significantly larger effective orifice area 1 year postoperatively (1.9 ± 0.5 vs 1.7 ± 0.4 cm2; P = 0.047). Paravalvular leaks, however, were significantly more common in the MIS-RDAVR group (P = 0.027). CONCLUSIONS: MIS-RDAVR is associated with a significantly reduced cross-clamp time and better valvular haemodynamic function than FS-AVR. However, paravalvular leak rates are higher with MIS-RDAVR.


Assuntos
Estenose da Valva Aórtica/cirurgia , Implante de Prótese de Valva Cardíaca , Procedimentos Cirúrgicos Minimamente Invasivos , Idoso , Bioprótese , Feminino , Próteses Valvulares Cardíacas , Implante de Prótese de Valva Cardíaca/instrumentação , Implante de Prótese de Valva Cardíaca/métodos , Hemodinâmica , Humanos , Masculino , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Estudos Prospectivos
20.
Circulation ; 110(11 Suppl 1): II74-8, 2004 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-15364842

RESUMO

BACKGROUND: Standard stented aortic xenograft valves have not yet been compared regarding their hemodynamic function using a stratified intraoperative randomization protocol. METHODS AND RESULTS: 100 patients were prospectively included after intraoperative metric sizing of the decalcified aortic annulus. They received Mosaic (M) or Perimount (P) aortic valve replacement. Patient age was 73+/-5 years, 51 were female, and New York Heart Association (NYHA) functional class was 2.8+/-0.5. The 21-mm annulus group consisted of 5 (M)/7 (P) patients, the 23-mm annulus group of 20 (M)/20 (P), the 25-mm annulus group of 18 (M)/19 (P), and the 27-mm annulus group of 4 (M)/7 (P) patients, respectively. Hemodynamic function was evaluated using transthoracic echocardiography before discharge and at follow-up (438+/-352 days). Surgery was uncomplicated in all patients. Labeled valve sizes were 0.93 (M) and 1.05 (P) mm smaller than the annulus diameters (p=NS). In-hospital mortality was 5%, all nonvalve-related. Transvalvular blood flow velocities and transvalvular pressure gradients were significantly lower in the 25 P versus the 25 M group at baseline and in the 23 P and 25 P groups at follow-up. There was a significant regression of left ventricular mass index in all patients at follow-up. However, left ventricular mass regression was more pronounced after P aortic valve replacement. CONCLUSIONS: Labeled sizes of prosthetic heart valves implanted are smaller than the true aortic annulus. Both standard aortic xenografts compared in this prospectively randomized trial provide a sufficient hemodynamic and functional outcome.


Assuntos
Estenose da Valva Aórtica/cirurgia , Valva Aórtica/cirurgia , Bioprótese , Próteses Valvulares Cardíacas , Hemodinâmica , Stents , Idoso , Animais , Bioprótese/normas , Superfície Corporal , Calcinose/prevenção & controle , Bovinos , Materiais Revestidos Biocompatíveis , Morte Súbita Cardíaca/epidemiologia , Detergentes/administração & dosagem , Desenho de Equipamento , Feminino , Seguimentos , Próteses Valvulares Cardíacas/normas , Mortalidade Hospitalar , Humanos , Hipertrofia Ventricular Esquerda/etiologia , Hipertrofia Ventricular Esquerda/cirurgia , Infecções/epidemiologia , Masculino , Insuficiência de Múltiplos Órgãos/epidemiologia , Complicações Pós-Operatórias/epidemiologia , Estudos Prospectivos , Acidente Vascular Cerebral/epidemiologia , Tensoativos/administração & dosagem , Sus scrofa , Resultado do Tratamento
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