Activated carbon adsorbate loading at equilibrium (ω*) as a function of initial mercury concentration (c0), temperature and oxygen partial pressure. Symbols: experimental results; lines: model ...results.◊ pO2=99.3kPa, □ pO2=20.8kPa, ○ pO2=4.9kPa, + pO2=0kPa (100% N2). Display omitted
•We studied Hg0 adsorption on activated carbon in different O2/N2 streams.•The experiments led to the determination of the breakthrough curves for fixed bed.•The influence of oxygen during pre-treatment and during adsorption is studied.•Experiments showed that O2 in the gas phase increases the adsorption capacity.•Oxygen has a twofold effect, increasing active sites and modifying carbon surface.
The main purpose of this paper is the study of elemental mercury adsorption phenomena on a commercially available activated carbon in different oxygen/nitrogen streams. A laboratory-scale apparatus with a fixed bed was used to adsorb elemental mercury vapors in an oxygen/nitrogen stream (synthetic gas). Temperature was varied from 90 to 150°C. The inlet gas stream was a nitrogen/oxygen mixture with oxygen partial pressures varying from 4.9 to 99.3kPa, in this gas stream elemental mercury vapors was added spanning the mercury concentration from 0.3 to 3mg/m3. A commercial activated carbon (Darco G60 from BDH) was utilized as sorbent.
The experiments led to the determination of the breakthrough curves for the fixed bed. Saturation data allow determining the adsorption isotherms for the temperatures tested, at the different oxygen partial pressures investigated. Experiments showed that the presence of oxygen in the gas phase increases the adsorption capacity of the sorbent and the higher the oxygen concentration the higher the adsorption capacity; however an unusual trend of the adsorption capacity as a function of the temperature was observed, suggesting the occurrence of different phenomena. In order to explain this trend a set of ad hoc experiments was realized pre-treating the carbon in oxygen/nitrogen gas phase and performing the adsorption of mercury in a nitrogen gas phase. These experiments allow the definition of a new model that accounts for the phenomena occurring during mercury adsorption in gas phase containing oxygen. Eventually, the model results well fit the experimental findings.
Children with uncontrolled asthma are less tolerant to exercise due to ventilatory limitation, exercise-induced bronchoconstriction (EIB), or physical deconditioning. The contribution of these ...factors in children with controlled mild-to-moderate asthma is unknown.
To explore the underlying mechanisms of reduced exercise capacity in children with controlled mild-to-moderate asthma.
This was a cross-sectional study of 45 children and adolescents (age 8-18 years) with controlled mild-to-moderate asthma (asthma control test score 21-25) and 61 age-matched healthy controls. All participants completed a physical activity questionnaire and performed spirometry and cardiopulmonary exercise testing (CPET; maximal incremental protocol). Spirometric indices and CPET parameters were compared between the two groups. The effect of EIB (FEV
decrease >10% post CPET), ventilatory limitation and physical deconditioning on maximum oxygen uptake (O
peak), was assessed by multivariable linear regression.
62.2% of children with asthma and 29.5% of controls (P = 0.002) were categorized as inactive. Reduced exercise capacity (O
peak <80%) was noted in 53.3% of asthmatics and 16.4% of controls (P < 0.001). EIB was documented in 11.1% of participants with asthma. Physical deconditioning was noted in 37.8% of children with asthma and in 14.8% of controls (P = 0.013). Physical deconditioning emerged as the only significant determinant of O
peak, irrespective of asthma diagnosis, body mass index, ventilatory limitation and EIB.
Children with controlled mild-to-moderate asthma are less tolerant to strenuous exercise than their healthy peers. The decreased exercise capacity in this population should mainly be attributed to physical deconditioning, while the contribution of ventilatory limitation and EIB is rather small.
Abstract Background Increased incidence of congenital heart disease (CHD) has been reported in the offspring of monochorionic twin gestations. Assisted reproductive technology (ART), which is related ...to increased rates of twinning, has also been associated with higher risk of birth defects. We studied the incidence of CHD in a cohort of twins to clarify the contribution of type of conception and chorionicity. Methods Data concerning 874 live-born twins of which at least one was admitted in our Neonatal Unit during 1995–2012 were analysed. Forty-five % (N = 197) of the gestations resulted from ART (in vitro fertilisation or intracytoplasmic sperm insertion). Results In the ART group 32/389 (8.2%) had CHD compared to 21/485 (4.3%) infants conceived naturally (OR 1.90, 95%CI 1.08–3.34, p = 0.024). Spontaneous-conception gestations had higher incidence of monochorionic placentation (47/245 versus 4/197, p < 0.001), and included younger mothers (29.1 ± 5.2 versus 33.9 ± 5.5 years, p < 0.001) who had higher parity (median 2 range 1–7 versus 1 Pinborg (2005), Blondel and Kaminski (2002), Knopman et al. (2014), Kyvik and Derom (2006) ; p < 0.001). Multivariable logistic regression analysis showed that ART (OR 2.60, 95% CI 1.24–5.45) and monochorionicity (OR 3.49, 95% CI 1.57–7.77) were significant determinants of CHD, independently of maternal age, parity, and the gender of the offspring. Conclusions We confirmed that monochorionic twins have increased risk of CHD and we documented a higher incidence of CHD in ART twins independently of chorionicity. We suggest improvement of echocardiographic skills of health care professionals involved in prenatal screening and foetal cardiology referral of ART dichorionic twins with suspicious findings at screening, in addition to all monochorionic gestations.
The early postnatal cardiovascular consequences of intrauterine growth restriction (IUGR) have not been completely elucidated. This study aimed to evaluate the effect of IUGR on neonatal myocardial ...function and cardiovascular adaptation to extrauterine life.
Conventional and tissue Doppler echocardiographic parameters were compared on the second and fifth postnatal day between 30 IUGR and 30 appropriate-for-gestational age (AGA) neonates.
IUGR neonates presented relative interventricular septum (IVS) hypertrophy (IVS to left ventricular (LV) posterior wall diastolic ratio: median IUGR-AGA difference of 0.05 (interquartile range: 0.04-0.06); P = 0.020), relative LV dilatation (wall thickness to end-diastolic LV dimension difference of 0.12 (0.06-0.16); P = 0.012), and increased left myocardial performance index (MPI difference of 0.19 (0.05-0.28); P = 0.012). Repeated measurements ANOVA revealed a different pattern of change in LV stroke volume (LVSV; P < 0.001), LV cardiac output (LVCO; P < 0.001), MPI (P < 0.001), and heart rate (HR; P = 0.025) between AGA and IUGR infants. From the second to the fifth postnatal day, AGA neonates presented a decrease in MPI and HR with an increase in LVSV and LVCO. IUGR neonates failed to achieve similar changes in MPI, HR, and LVSV, whereas their LVCO decreased.
IUGR neonates present changes in cardiac morphology and subclinical myocardial dysfunction, which may result in an altered pattern of cardiovascular adaptation to extrauterine life.
Preeclampsia Emerging as a Risk Factor of Cardiovascular Disease in Women Chourdakis, Emmanouil; Oikonomou, Nikos; Fouzas, Sotirios ...
High blood pressure & cardiovascular prevention : the official journal of the Italian Society of Hypertension,
03/2021, Letnik:
28, Številka:
2
Journal Article
Recenzirano
The objective of this literature review was to explore the long-term cardiovascular effects of preeclampsia in women. The primary goal was to determine which organs were most commonly affected in ...this population. Although it was previously believed that preeclampsia is cured after the delivery of the fetus and the placenta current evidence supports an association between preeclampsia and cardiovascular disease later in life, many years after the manifestation of this hypertensive pregnancy related disorder. Therefore preeclampsia may be emerging as a novel cardiovascular risk factor for women, which requires long-term follow up.
Pre-eclampsia is a known risk factor for long-term cardiovascular complications. Osteoprotegerin (OPG) and the receptor activator of nuclear factor κB ligand (RANKL) have been implicated in the ...pathogenesis of cardiovascular disease. The OPG-RANKL axis function is also altered in pregnant women with pre-eclampsia, but there is lack of data regarding OPG and RANKL concentrations in their neonates.
To examine the effects of early-onset pre-eclampsia on OPG and RANKL serum concentrations at birth, taking into account the influence of various perinatal factors.
OPG and RANKL serum concentrations were measured in 28 premature newborns of mothers with early onset pre-eclampsia, and in 28 preterm and 28 full-term neonates of normotensive mothers (control groups).
Neonates of pre-eclamptic mothers had higher OPG and lower RANKL levels compared to both control groups (Kruskal-Wallis P < 0.0001 and P = 0.014, respectively). Regression analysis showed that pre-eclampsia (P < 0.0001), birth weight z-score (P = 0.048) and antenatal steroid administration (P = 0.034) were significant determinants of OPG levels. Multivariable regression analysis also showed that pre-eclampsia was an independent predictor of increased diastolic and mean blood pressure in these neonates.
Early-onset pre-eclampsia affects OPG concentrations at birth and is an independent predictor of increased blood pressure in the offspring. Our findings suggest that altered OPG-RANKL axis function may be one of the mechanisms of cardiovascular ‘programming’ in fetuses exposed to pre-eclampsia.
•OPGRANKL have been implicated in the pathogenesis of cardiovascular disease•Serum OPG and OPG/RANKL are higher in newborns exposed to early-onset pre-eclampsia•Pre-eclampsia is an independent predictor of high blood pressure in the offspring•OPG may be involved in the cardiovascular ‘programming’ of pre-eclamptic fetuses
To the Editor,
The incidence of congenital heart disease is fairly high in neonates with heart murmurs, ranging from 22% to 86% across studies (1). Therefore, low threshold of referral is recommended ...in this patient population. A cardiac murmur is identified in approximately 2% of routine neonatal examinations (2). The absence of a murmur does not preclude congenital heart disease. Indeed, more than half of the neonates with congenital heart disease diagnosed in infancy are missed on routine neonatal examination and more than one third are missed at the 6th-week examination (3).
As cloud computing evolves, it is becoming more and more apparent that the future of this industry lies in interconnected cloud systems where resources will be provided by multiple “Cloud” providers ...instead of just one. In this way, the hosts of services that are cloud-based will have access to even larger resource pools while at the same time increasing their scalability and availability by diversifying both their computing resources and the geographical locations where those resources operate from. Furthermore the increased competition between the cloud providers in conjunction with the commoditization of hardware has already led to large decreases in the cost of cloud computing and this trend is bound to continue in the future. Scientific focus in cloud computing is also headed this way with more studies on the efficient allocation of resources and effective distribution of computing tasks between those resources. This study evaluates the use of meta-heuristic optimization algorithms in the scheduling of bag-of-tasks applications in a heterogeneous cloud of clouds. The study of both local and globally arriving jobs has been considered along with the introduction of sporadically arriving critical jobs. Simulation results show that the use of these meta-heuristics can provide significant benefits in costs and performance.
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