549 research outputs found
Effect of Vacuum on Venous Drainage: an Experimental Evaluation on Pediatric Venous Cannulas and Tubing Systems.
Introduction: To observe how vacuum assisted venous drainage (VAVD) may influence the flow in a cardiopulmonary bypass circuit with different size of venous lines and cannulas.
Methods: The experimental circuit was assembled to represent the cardiopulmonary bypass circuit routinely used during cardiac surgery. Wall suction was applied directly, modulated and measured into the venous reservoir. The blood flow was measured with a flow-meter positioned on the venous line. The circuit prime volume was replaced with group O date expired re-suspended red cells and Plasmalyte 148 to a hematocrit of 28% to 30%.
Results: In an open circuit with gravity siphon venous drain, angled cannulae drain more than straight ones regardless the amount of suction applied to the venous line (16 Fr straight cannula (S) drains 90 ml/min less than a 16 Fr angled (A) with a siphon gravity). The same flow can be obtained with lower cannula size and higher suction (i.e. 12 A with and -30 mmHg). Tables have been created to list how the flow varies according to the size of the cannulas, the size of the venous tubes, and the amount of suction applied to the system.
Conclusions: Vacuum assisted venous drainage allows the use of smaller cannulae and venous lines to maintain a good venous return, which is very useful during minimally invasive approaches. The present study should be considered as a preliminary attempt to create a scientific-based starting point for a uniform the use of VAVD.
Keywords: cardio-pulmonary bypass; experimental study; vacuum assisted drainage
An extensive photometric study of the Blazhko RR Lyrae star RZ Lyr
The analysis of recent, extended multicolour CCD and archive photoelectric,
photographic and visual observations has revealed several important properties
of RZ Lyr, an RRab-type variable exhibiting large-amplitude Blazhko modulation.
On the time-base of \sim110 yr, a strict anticorrelation between the pulsation
and modulation period changes is established. The light curve of RZ Lyr shows a
remarkable bump on the descending branch in the small-amplitude phase of the
modulation, similarly to the light curves of bump Cepheids. We speculate that
the stellar structure temporally suits a 4:1 resonance between the periods of
the fundamental and one of the higher-order radial modes in this modulation
phase. The light-curve variation of RZ Lyr can be correctly fitted with a
two-modulation-component solution; the 121 d period of the main modulation is
nearly but not exactly four times longer than the period of the secondary
modulation component. Using the inverse photometric method, the variations in
the pulsation-averaged values of the physical parameters in different phases of
both modulation components are determined.Comment: 15 pages, 14 figures, 8 tables. Published in MNRAS, 2012. [v3]: Only
change: title correcte
Effect of preoperative pulmonary hemodynamic and cardiopulmonary bypass on lung function in children with congenital heart disease
In children with congenital heart disease (CHD), pulmonary blood flow (Qp) contributes to alterations of pulmonary mechanics and gas exchange, while cardiopulmonary bypass (CPB) induces lung edema. We aimed to determine the effect of hemodynamics on lung function and lung epithelial lining fluid (ELF) biomarkers in biventricular CHD children undergoing CPB. CHD children were classified as high Qp (n = 43) and low Qp (n = 17), according to preoperative cardiac morphology and arterial oxygen saturation. We measured ELF surfactant protein B (SP-B) and myeloperoxidase activity (MPO) as indexes of lung inflammation and ELF albumin as index of alveolar capillary leak in tracheal aspirate (TA) samples collected before surgery and in 6 hourly intervals within 24 h after surgery. At the same time points, we recorded dynamic compliance and oxygenation index (OI). The same biomarkers were measured in TA samples collected from 16 infants with no cardiorespiratory diseases at the time of endotracheal intubation for elective surgery. Preoperative ELF biomarkers in CHD children were significantly increased than those found in controls. In the high Qp, ELF MPO and SP-B peaked 6 h after surgery and tended to decrease afterward, while they tended to increase within the first 24 h in the low Qp. ELF albumin peaked 6 h after surgery and decreased afterwards in both CHD groups. Dynamic compliance/kg and OI significantly improved after surgery only in the High Qp. Conclusion: In CHD children, lung mechanics, OI, and ELF biomarkers were significantly affected by CPB, according to the preoperative pulmonary hemodynamics.What is Known:• Congenital heart disease children, before cardiopulmonary run, exhibit changes in respiratory mechanics, gas exchange, and lung inflammatory biomarkers that are related to the preoperative pulmonary hemodynamics.• Cardiopulmonary bypass induces alteration of lung function and epithelial lining fluid biomarkers according to preoperative hemodynamics.What is New:• Our findings can help to identify children with congenital heart disease at high risk of postoperative lung injury who may benefit of tailored intensive care strategies, such as non-invasive ventilation techniques, fluid management, and anti-inflammatory drugs that can improve cardiopulmonary interaction in the perioperative period
Abiotic stress response of near-isogenic spring durum wheat lines under different sowing densities
A detailed study was made of changes in the plant development, morphology, physiology and yield biology of near-isogenic lines of spring durum wheat sown in the field with different plant densities in two consecutive years (2013–2014). An analysis was made of the drought tolerance of isogenic lines selected for yield QTLs (QYld.idw-2B and QYld.idw-3B), and the presence of QTL effects was examined in spring sowings. Comparisons were made of the traits of the isogenic pairs QYld.idw-3B++ and QYld.idw-3B−− both within and between the pairs. Changes in the polyamine content, antioxidant enzyme activity, chlorophyll content of the flag leaf and the normalized difference vegetation index (NDVI) of the plot were monitored in response to drought stress, and the relationship between these components and the yield was analyzed. In the case of moderate stress, differences between the NIL++ and NIL−− pairs appeared in the early dough stage, indicating that the QYld.idw-3B++ QTL region was able to maintain photosynthetic activity for a longer period, resulting in greater grain number and grain weight at the end of the growing period. The chlorophyll content of the flag leaf in phenophases Z77 and Z83 was significantly correlated with the grain number and grain weight of the main spike. The grain yield was greatly influenced by the treatment, while the genotype had a significant effect on the thousand-kernel weight and on the grain number and grain weight of the main spike. When the lines were compared in the non-irrigated treatment, significantly more grains and significantly higher grain weight were observed in the main spike in NIL++ lines, confirming the theory that the higher yields of the QYld.idw-3B++ lines when sown in spring and exposed to drought stress could be attributed to the positive effect of the “Kofa” QTL on chromosome 3B
Protective continuous ventilation strategy during cardiopulmonary bypass in children undergoing surgery for congenital heart disease: a prospective study
OBJECTIVES: The aim of this study was to evaluate if a 'protective' (low-tidal/low-frequency) ventilation strategy can shorten the postoperative ventilation time and minimize acute lung injury in children with congenital heart disease (CHD) undergoing repair with cardiopulmonary bypass (CPB). METHODS: This is a single-centre prospective, interventional study, including children with CHD under the age of 5 years, undergoing open-heart surgery with a CPB >60 min, in hypothermia, haemodynamically stable, and without evident genetic abnormalities. Assist-control ventilation (tidal volume of 4 ml/kg, 10 breaths/min, positive end-expiratory pressure 5 cmH2O and FiO2 0.21) was applied in a cohort of patients during CPB. We compared clinical outcomes and in fully ventilated versus non-ventilated (control) patients. Propensity score was used to weigh ventilated and control groups to correct for the effect of other confounding clinical variables. Clinical and ventilation parameters and lung inflammatory biomarkers in tracheal aspirates were measured. The primary outcome was the postoperative intubation time of more or less than 48 h. RESULTS: We included 140 children (53 ventilated, 87 non-ventilated) with different CHD. There were no deaths or adverse events in ventilated patients. Using a weighted generalized linear model, we found no sufficient evidence for an effect of intraoperative ventilation on postoperative intubation time [estimate 0.13 (95% confidence interval, -0.08; 0.35), P = 0.22]. CONCLUSIONS: Continuous low-tidal/low-frequency mechanical ventilation during CPB is safe and harmless. However, no significant advantages were found when compared to non-ventilated patients in terms of postoperative ventilation time
Decellularized cryopreserved human pericardium: a validation study towards tissue bank practice
Pericardial patches are currently used as reconstructive material in cardiac surgery for surgical treatment of cardiac septal defects. Autologous pericardial patches, either treated with glutaraldehyde or not, can be used as an alternative to synthetic materials or xenograft in congenital septal defects repair. The availability of an allogenic decellularized pericardium could reduce complication during and after surgery and could be a valid alternative. Decellularization of allogenic tissues aims at reducing the immunogenic reaction that might trigger inflammation and tissue calcification over time. The ideal graft for congenital heart disease repair should be biocompatible, mechanically resistant, non-immunogenic, and should have the ability to growth with the patients. The aim of the present study is the evaluation of the efficacy of a new decellularization protocol of homologous pericardium, even after cryopreservation. The technique has proven to be suitable as a tissue bank procedure and highly successful in the removal of cells and nucleic acids content, but also in the preservation of collagen and biomechanical properties of the human pericardium
Germinação in vitro e viabilidade polínica em Passifloras silvestres.
Os programas de melhoramento genético em Passiflora utilizam, em sua maioria, as espécies silvestres como fontes de resistência a doenças. Porém, novo enfoque vem sendo dado para sua utilização como plantas ornamentais. O objetivo do trabalho foi identificar o meio adequado para a germinação in vitro de pólen de seis espécies silvestres de maracujazeiro bem como examinar a viabilidade do pólen por meio do uso do corante 2,3,5-cloreto de trifeniltetrazólio (TTC) e do lugol. O meio de cultura contendo 0,03% de Ca(NO3).4H2O, 0,02% de Mg(SO4) . 7H2O, 0,01% de KNO3, 0,01% de H3BO3, 15% de sacarose, solidificado com 0,8% de ágar e pH ajustado para 7,0, proporcionou maior percentual de grãos de pólen germinados. O corante TTC e o lugol, superestimou a viabilidade de pólen, já que todos os acessos apresentaram índice de viabilidade alto, quando comparado aos resultados obtidos in vitro
Extensive Spectroscopy and Photometry of the Type IIP Supernova 2013ej
We present extensive optical (, , and open CCD) and
near-infrared () photometry for the very nearby Type IIP SN ~2013ej
extending from +1 to +461 days after shock breakout, estimated to be MJD
. Substantial time series ultraviolet and optical spectroscopy
obtained from +8 to +135 days are also presented. Considering well-observed SNe
IIP from the literature, we derive bolometric calibrations from
and unfiltered measurements that potentially reach 2\% precision with a
color-dependent correction. We observe moderately strong Si II
as early as +8 days. The photospheric velocity () is
determined by modeling the spectra in the vicinity of Fe II
whenever observed, and interpolating at photometric epochs based on a
semianalytic method. This gives km s at +50
days. We also observe spectral homogeneity of ultraviolet spectra at +10--12
days for SNe IIP, while variations are evident a week after explosion. Using
the expanding photosphere method, from combined analysis of SN 2013ej and SN
2002ap, we estimate the distance to the host galaxy to be
Mpc, consistent with distance estimates from other methods. Photometric and
spectroscopic analysis during the plateau phase, which we estimated to be
days long, yields an explosion energy of
ergs, a final pre-explosion progenitor mass of ~M and a
radius of ~R. We observe a broken exponential profile beyond
+120 days, with a break point at + days. Measurements beyond this
break time yield a Ni mass of ~M.Comment: 29 pages, 23 figures, 15 tables, Published in The Astrophisical
Journa
The Konkoly Blazhko Survey: Is light-curve modulation a common property of RRab stars?
A systematic survey to establish the true incidence rate of the Blazhko
modulation among short-period, fundamental-mode, Galactic field RR Lyrae stars
has been accomplished. The Konkoly Blazhko Survey (KBS) was initiated in 2004.
Since then more than 750 nights of observation have been devoted to this
project. A sample of 30 RRab stars was extensively observed, and light-curve
modulation was detected in 14 cases. The 47% occurrence rate of the modulation
is much larger than any previous estimate. The significant increase of the
detected incidence rate is mostly due to the discovery of small-amplitude
modulation. Half of the Blazhko variables in our sample show modulation with so
small amplitude that definitely have been missed in the previous surveys. We
have found that the modulation can be very unstable in some cases, e.g. RY Com
showed regular modulation only during one part of the observations while during
two seasons it had stable light curve with abrupt, small changes in the
pulsation amplitude. This type of light-curve variability is also hard to
detect in other Survey's data. The larger frequency of the light-curve
modulation of RRab stars makes it even more important to find the still lacking
explanation of the Blazhko phenomenon. The validity of the [Fe/H](P,phi_{31})
relation using the mean light curves of Blazhko variables is checked in our
sample. We have found that the formula gives accurate result for
small-modulation-amplitude Blazhko stars, and this is also the case for
large-modulation-amplitude stars if the light curve has complete phase
coverage. However, if the data of large-modulation-amplitude Blazhko stars are
not extended enough (e.g. < 500 data points from < 15 nights), the formula may
give false result due to the distorted shape of the mean light curve used.Comment: Accepted for publication in MNRAS, 14 pages, 7 Figure
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