Maternal nicotine exposure during gestation and lactation interferes with alveolar development in the neonatal lung

1998 ◽  
Vol 10 (3) ◽  
pp. 255 ◽  
Author(s):  
G. S. Maritz ◽  
H. Dennis
Keyword(s):  
Gas Exchange ◽  
Internal Surface ◽  
Nicotine Exposure ◽  
Internal Surface Area ◽  
Pregnant Rats ◽  
Nicotine Administration ◽  
Neonatal Lung ◽  
Pregnancy And Lactation ◽  
Radial Alveolar Count ◽  
Exposure During Pregnancy

The aim of this study was to investigate the effect of maternal nicotine exposure during pregnancy and lactation on the development of the lungs of the offspring as a gas- exchanger. Pregnant rats received nicotine (1 mg/kg body mass day–1) subcutaneously during gestation and lactation. Nicotine administration started one day after mating and lasted until weaning on post natal Day 21. The offspring were exposed to nicotine only via the placenta and the milk of the mother. The lung tissue of the neonates was collected on post natal Days 14, 21, 35 and 42 and prepared for morphometry. The results obtained show that maternal nicotine exposure suppressed alveolarisation in the lungs of the offspring, which resulted in a reduced internal surface area available for gas exchange. The radial alveolar count as well as the number of capillaries in the septa were also significantly lower than in the control animals. It is concluded that maternal nicotine exposure had an adverse effect on the development of the gas exchange region of the lungs of the offspring that persisted at least up to Day 42 after birth.

Effect of Nicotine Exposure During Pregnancy and Lactation on Maternal, Fetal, and Postnatal Rat IGF-II Profile

2009 ◽  
Vol 16 (9) ◽  
pp. 875-882 ◽  
Author(s):  
Andrée Gruslin ◽  
Carolyn E. Cesta ◽  
Michael Bell ◽  
Qing Qiu ◽  
Maria A. Petre ◽  
...  
Keyword(s):  
Nicotine Exposure ◽  
Pregnancy And Lactation ◽  
Exposure During Pregnancy

Influence of maternal nicotine exposure on neonatal rat oxidant–antioxidant system and effect of ascorbic acid supplementation

2008 ◽  
Vol 27 (10) ◽  
pp. 781-786 ◽  
Author(s):  
T Gunes ◽  
E Koklu ◽  
I Gunes ◽  
F Narin ◽  
SS Koklu
Keyword(s):  
Oxidative Stress ◽  
Ascorbic Acid ◽  
Birth Weight ◽  
Adverse Effects ◽  
Antioxidant System ◽  
Neonatal Rat ◽  
Nicotine Exposure ◽  
Pregnant Rats ◽  
Pregnancy And Lactation ◽  
Group 3

There have been a few studies that examined the oxidative stress effects of nicotine during pregnancy and lactation. We aimed to determine the adverse effects of maternal nicotine exposure during pregnancy and lactation on oxidant–antioxidant system, and to determine a protective effect of ascorbic acid (Asc). Gravid rats were assigned into four groups. In Group 1, pregnant rats received 6-mg/kg/day nicotine subcutaneously during pregnancy from 1 to 21 days of gestation and lactation (until postnatal day 21). Group 2 received nicotine and Asc for the same period. In Group 3, the rats received nicotine during lactation. Control pregnant rats (Group 4) received only saline subcutaneously. Serum malondialdehyde (MDA), myeloperoxidase (MPO), and superoxide dismutase (SOD) levels were determined at 21 days of age. Nicotine exposure decreased birth weight and pregnancy weight gain. MDA values of the rat pups exposed to nicotine in both Groups 1 and 2 were higher than those of control and Group 3. SOD and MPO values of the groups were similar. Mean birth weight and serum MDA levels of Groups 1 and 2 were similar. Nicotine exposure via placental transfer increases oxidative stress as manifested by an increase in MDA level. Asc supplementation does not prevent the adverse effects of maternal nicotine exposure.

What catalysis needs from the electron microscopist

1988 ◽  
Vol 46 ◽  
pp. 694-695
Author(s):  
Alexis T. Bell
Keyword(s):  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Catalyst Deactivation ◽  
Surface Composition ◽  
Internal Surface ◽  
Active Phase ◽  
Atomic Scale ◽  
Metal Catalyst ◽  
Internal Surface Area ◽  
Porous Support

Heterogeneous catalysts, used in industry for the production of fuels and chemicals, are microporous solids characterized by a high internal surface area. The catalyticly active sites may occur at the surface of the bulk solid or of small crystallites deposited on a porous support. An example of the former case would be a zeolite, and of the latter, a supported metal catalyst. Since the activity and selectivity of a catalyst are known to be a function of surface composition and structure, it is highly desirable to characterize catalyst surfaces with atomic scale resolution. Where the active phase is dispersed on a support, it is also important to know the dispersion of the deposited phase, as well as its structural and compositional uniformity, the latter characteristics being particularly important in the case of multicomponent catalysts. Knowledge of the pore size and shape is also important, since these can influence the transport of reactants and products through a catalyst and the dynamics of catalyst deactivation.

scholarly journals Heat-Up Performance of Catalyst Carriers—A Parameter Study and Thermodynamic Analysis

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 964
Author(s):  
Thomas Steiner ◽  
Daniel Neurauter ◽  
Peer Moewius ◽  
Christoph Pfeifer ◽  
Verena Schallhart ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Surface Area ◽  
Internal Surface ◽  
Installation Space ◽  
Parameter Study ◽  
Thin Wall ◽  
Primary Role ◽  
Internal Surface Area

This study investigates geometric parameters of commercially available or recently published models of catalyst substrates for passenger vehicles and provides a numerical evaluation of their influence on heat-up behavior. Parameters considered to have a significant impact on the thermal economy of a monolith are: internal surface area, heat transfer coefficient, and mass of the converter, as well as its heat capacity. During simulation experiments, it could be determined that the primary role is played by the mass of the monolith and its internal surface area, while the heat transfer coefficient only has a secondary role. Furthermore, an optimization loop was implemented, whereby the internal surface area of a commonly used substrate was chosen as a reference. The lengths of the thin wall and high cell density monoliths investigated were adapted consecutively to obtain the reference internal surface area. The results obtained by this optimization process contribute to improving the heat-up performance while simultaneously reducing the valuable installation space required.

Impingement/Effusion Cooling Wall Heat Transfer: Reduced Number of Impingement Jet Holes Relative to the Effusion Holes

2017 ◽  
Author(s):  
Abubakar M. El-Jummah ◽  
Ahmad Nazari ◽  
Gordon E. Andrews ◽  
John E. J. Staggs
Keyword(s):  
Heat Transfer ◽  
Internal Surface ◽  
Surface Flow ◽  
Electrical Heating ◽  
Wall Heat Transfer ◽  
Internal Wall ◽  
Suction Surface ◽  
Internal Surface Area ◽  
Impingement Jet ◽  
Effusion Hole

Internal wall heat transfer for impingement/effusion cooling was measured and predicted using conjugate heat transfer (CHT) computational fluid dynamics (CFD). The work was only concerned with the internal wall heat transfer and not with the effusion film cooling and there was no hot gas crossflow. Previous work had predicted impingement/effusion internal wall cooling with equal number of holes. The present work investigated a small number of impingement holes and a larger number of effusion holes. The aim was to see if the effusion holes acted as a suction surface to the impingement surface flow and thus enhanced the wall heat transfer. Hole ratios of 1/4, 1/9 and 1/25 were studied by varying the number of effusion holes for a fixed array of impingement holes and a fixed impingement gap, Z, of 8 mm. The Z/D for the impingement holes was 2.7. The impingement hole pitch, X, to diameter, D ratio X/D was 10.6 at a constant effusion hole X/D of 4.7 for all the configurations. The impingement holes were aligned on the midpoint of four effusion holes. The results were computed for a mass flux G from 0.1–0.94 kg/sm2bar for all n. This gave 26 separate CFD/CHT computations. Locally surface, X2, average heat transfer coefficient (HTC), hx, values were determined using the lumped capacitance method. Nimonic 75 metal walls with imbedded thermocouples were used to determine hx from the time constant in a transient cooling experiment following electrical heating to about 80°C. The CHT/CFD predictions showed good agreement with measured data and the highest number of effusion holes for the 1/25 hole ratio gave the highest h. However, comparison with the predicted and experimental results for equal number of impingement and effusion holes for the same Z, showed that there was little advantage of decreasing the number of impingement holes, apart from that of decreasing the Z/D significantly for the 1/15 hole ratio, which increased the heat transfer. The largest number of effusion holes had the highest heat transfer due to the greater internal surface area of the holes and their closer spacing. This was present irrespective of the number of impingement holes and there was no evidence of any benefit of the 25 effusion holes enhancing the single impingement jet heat transfer. For the lowest number of effusion hole there was predicted to be a small disadvantage of reducing the number of impingement jets.

scholarly journals Impact of Nanoparticle Consolidation on Charge Separation Efficiency in Anatase TiO2 Films

2021 ◽  
Vol 9 ◽  
Author(s):  
Karin Rettenmaier ◽  
Thomas Berger
Keyword(s):  
Thermal Annealing ◽  
Charge Separation ◽  
Separation Efficiency ◽  
Internal Surface ◽  
Processing Temperature ◽  
Cyclic Voltammograms ◽  
Internal Surface Area ◽  
Deep Traps ◽  
Charge Separation Efficiency ◽  
The Impact

Mesoporous films and electrodes were prepared from aqueous slurries of isolated anatase TiO2 nanoparticles. The resulting layers were annealed in air at temperatures 100°C ≤ T ≤ 450°C upon preservation of internal surface area, crystallite size and particle size. The impact of processing temperature on charge separation efficiency in nanoparticle electrodes was tracked via photocurrent measurements in the presence of methanol as a hole acceptor. Thermal annealing leads to an increase of the saturated photocurrent and thus of the charge separation efficiency at positive potentials. Furthermore, a shift of capacitive peaks in the cyclic voltammograms of the nanoparticle electrodes points to the modification of the energy of deep traps. Population of these traps triggers recombination possibly due to the action of local electrostatic fields attracting photogenerated holes. Consequently, photocurrents saturate at potentials, at which deep traps are mostly depopulated. Charge separation efficiency was furthermore investigated for nanoparticle films and was tracked via the decomposition of hydrogen peroxide. Our observations evidence an increase of charge separation efficiency upon thermal annealing. The effect of particle consolidation, which we associate with minute atomic rearrangements at particle/particle contacts, is attributed to the energetic modification of deep traps and corresponding modifications of charge transport and recombination, respectively.

scholarly journals Detection of cotinine in neonate meconium as a marker for nicotine exposure in utero

2004 ◽  
Vol 10 (1-2) ◽  
pp. 96-105
Author(s):  
N. A. Sherif ◽  
S. M. Kamel ◽  
O. S. Al Ashkar ◽  
O. A. Sharaki ◽  
E. A. Seif ◽  
...  
Keyword(s):  
Neonatal Period ◽  
Biological Marker ◽  
Maternity Hospital ◽  
Nicotine Exposure ◽  
Fetal Exposure ◽  
Tobacco Exposure ◽  
Cotinine Level ◽  
Salivary Cotinine ◽  
Pregnancy Urine ◽  
Exposure During Pregnancy

Neonate meconium cotinine level was evaluated as a marker of prenatal exposure to nicotine from tobacco smoking by mothers. Mothers admitted to a maternity hospital in Alexandria, Egypt, were divided into 3 groups:10 active smokers, 10 passive smokers and 10 with no tobacco exposure during pregnancy. Urine and saliva samples were collected from mothers and first-day meconium samples from their neonates. Mean maternal urinary cotinine levels, measured using radioimmunoassay, differed significantly between the 3 groups, as did mean salivary cotinine and mean cotinine levels in meconium. There was a significant positive correlation between cotinine levels in meconium and both maternal urinary and salivary cotinine levels. Meconium is an ideal biological marker for testing direct fetal exposure to tobacco smoke in the neonatal period

scholarly journals Plasma Catalysis: Distinguishing between Thermal and Chemical Effects

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 185 ◽  
Author(s):  
Guido Giammaria ◽  
Gerard van Rooij ◽  
Leon Lefferts
Keyword(s):  
Gas Phase ◽  
Surface Area ◽  
Thermal Effects ◽  
External Surface ◽  
Plasma Chemistry ◽  
Internal Surface ◽  
Plasma Power ◽  
External Surface Area ◽  
Internal Surface Area ◽  
Chemical Effects

The goal of this study is to develop a method to distinguish between plasma chemistry and thermal effects in a Dielectric Barrier Discharge nonequilibrium plasma containing a packed bed of porous particles. Decomposition of CaCO3 in Ar plasma is used as a model reaction and CaCO3 samples were prepared with different external surface area, via the particle size, as well as with different internal surface area, via pore morphology. Also, the effect of the CO2 in gas phase on the formation of products during plasma enhanced decomposition is measured. The internal surface area is not exposed to plasma and relates to thermal effect only, whereas both plasma and thermal effects occur at the external surface area. Decomposition rates were in our case found to be influenced by internal surface changes only and thermal decomposition is concluded to dominate. This is further supported by the slow response in the CO2 concentration at a timescale of typically 1 minute upon changes in discharge power. The thermal effect is estimated based on the kinetics of the CaCO3 decomposition, resulting in a temperature increase within 80 °C for plasma power from 0 to 6 W. In contrast, CO2 dissociation to CO and O2 is controlled by plasma chemistry as this reaction is thermodynamically impossible without plasma, in agreement with fast response within a few seconds of the CO concentration when changing plasma power. CO forms exclusively via consecutive dissociation of CO2 in the gas phase and not directly from CaCO3. In ongoing work, this methodology is used to distinguish between thermal effects and plasma–chemical effects in more reactive plasma, containing, e.g., H2.

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