Allometry of the mammalian intracellular pulmonary surfactant system

2010 ◽  
Vol 109 (6) ◽  
pp. 1662-1669 ◽  
Author(s):  
André Wirkes ◽  
Kristina Jung ◽  
Matthias Ochs ◽  
Christian Mühlfeld
Keyword(s):  
Surface Area ◽  
Pulmonary Surfactant ◽  
Human Lung ◽  
Mammalian Species ◽  
Weighted Mean ◽  
Electron Microscopic ◽  
Alveolar Epithelial ◽  
Interspecific Variations ◽  
Mean Size ◽  
The Mean

Alveolar epithelial (AE) surface area is closely correlated with body mass (BM) in mammals. The AE is covered by a surfactant layer produced by alveolar epithelial type II (AE2) cells. We hypothesized that the total number of AE2 cells and the volume of intracellular surfactant-storing lamellar bodies (Lb) are correlated with BM with a similar slope as AE surface area. We used light and electron microscopic stereology to estimate the number and mean volume of AE2 cells and the total volume of Lb in 12 mammalian species ranging from 2 to 3 g (Etruscan shrew) to 400–500 kg (horse) BM. The mean size of Lb was evaluated using the volume-weighted mean volume and the volume-to-surface ratio of Lb. The mean volume of AE2 cells was 500–600 μm3 in most species, but was higher in Etruscan shrew, guinea pig, and human lung. The mean volume of Lb per AE2 cell was 80–100 μm3 in most species, with the same exceptions as above. However, the total number of AE2 cells and the total volume of Lb were closely correlated with BM and exhibited an allometric relationship similar to the slope of AE surface area. The mean size of Lb was similar in all investigated species. In conclusion, the mean volume of AE2 cells and their Lb are independent of BM but show some interspecific variations. The adaptation of the intracellular surfactant pool size to BM is obtained by the variation of the number of AE2 cells in the lung.

scholarly journals Mechanical ventilation-induced alterations of intracellular surfactant pool and blood–gas barrier in healthy and pre-injured lungs

2020 ◽  
Author(s):  
Jeanne-Marie Krischer ◽  
Karolin Albert ◽  
Alexander Pfaffenroth ◽  
Elena Lopez-Rodriguez ◽  
Clemens Ruppert ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Blood Gas ◽  
Control Groups ◽  
Gas Barrier ◽  
Alveolar Epithelial ◽  
Alveolar Surfactant ◽  
Healthy Control ◽  
Mean Size ◽  
The Mean ◽  
Injury Progression

AbstractMechanical ventilation triggers the manifestation of lung injury and pre-injured lungs are more susceptible. Ventilation-induced abnormalities of alveolar surfactant are involved in injury progression. The effects of mechanical ventilation on the surfactant system might be different in healthy compared to pre-injured lungs. In the present study, we investigated the effects of different positive end-expiratory pressure (PEEP) ventilations on the structure of the blood–gas barrier, the ultrastructure of alveolar epithelial type II (AE2) cells and the intracellular surfactant pool (= lamellar bodies, LB). Rats were randomized into bleomycin-pre-injured or healthy control groups. One day later, rats were either not ventilated, or ventilated with PEEP = 1 or 5 cmH2O and a tidal volume of 10 ml/kg bodyweight for 3 h. Left lungs were subjected to design-based stereology, right lungs to measurements of surfactant proteins (SP−) B and C expression. In pre-injured lungs without ventilation, the expression of SP-C was reduced by bleomycin; while, there were fewer and larger LB compared to healthy lungs. PEEP = 1 cmH2O ventilation of bleomycin-injured lungs was linked with the thickest blood–gas barrier due to increased septal interstitial volumes. In healthy lungs, increasing PEEP levels reduced mean AE2 cell size and volume of LB per AE2 cell; while in pre-injured lungs, volumes of AE2 cells and LB per cell remained stable across PEEPs. Instead, in pre-injured lungs, increasing PEEP levels increased the number and decreased the mean size of LB. In conclusion, mechanical ventilation-induced alterations in LB ultrastructure differ between healthy and pre-injured lungs. PEEP = 1 cmH2O but not PEEP = 5 cmH2O ventilation aggravated septal interstitial abnormalities after bleomycin challenge.

The effects of population density and food surface area on body weight of Acheta domesticus (L.) (Orthoptera: Gryllidae)

1977 ◽  
Vol 55 (12) ◽  
pp. 2004-2010 ◽  
Author(s):  
Patricia S. Tennis ◽  
Joseph F. Koonce ◽  
Mitsuo Teraguchi
Keyword(s):  
Body Weight ◽  
Population Density ◽  
Emerging Adults ◽  
Surface Area ◽  
Development Time ◽  
Acheta Domesticus ◽  
Initial Population ◽  
Nymphal Development ◽  
Mean Size ◽  
The Mean

Experiments were performed to determine the effects of population density and food surface area on individual size (wet weight) of the house cricket, Acheta domesticus (L.). Three initial population densities (50, 200, and 400 hoppers per microcosm) were used to study the effects of population density, three food surface areas (one, two, and three petri dishes, 9.0 cm in diameter) were used to assess the effects of food surface area, and each treatment was replicated with three populations. Mortality increased and individual weight (at 53 days) decreased with increasing density. Both percentage survivorship and mean body weight increased with increasing food surface area. In both sets of experiments the mean size of emerging adults (0–24 h) decreased with increasing nymphal development time, and nymphal development time increased with increasing density and decreasing food surface area. On a daily comparison the mean size of emerging adults of both sexes decreased with increasing density, and the mean size of females increased with decreasing food surface area.

Optimization of the multichamber crystallizer

1979 ◽  
Vol 44 (4) ◽  
pp. 1239-1245 ◽  
Author(s):  
Jaroslav Nývlt ◽  
Luděk Provazník
Keyword(s):  
Mathematical Model ◽  
Surface Area ◽  
Temperature Difference ◽  
Large Temperature ◽  
Optimization Criteria ◽  
Temperature Distributions ◽  
Crystallization Surface ◽  
Mean Size ◽  
The Mean ◽  
Glauber Salt

Mathematical model of the multichamber crystallizer is proposed and is solved for various combinations of temperature distributions among individual chambers. Results of a series of calculations have demonstrated that the most important factors are the temperatures in the first two chambers of the crystallizer while sufficient crystallization surface area in other chambers suffices for reduction of supersaturation even at a large temperature difference. Optimization of the five-chamber crystallizer with the mean size of product crystals chosen as the optimization criteria is then performed for constants corresponding to crystallization of Glauber salt.

scholarly journals Linking Fibrotic Remodeling and Ultrastructural Alterations of Alveolar Epithelial Cells after Deletion of Nedd4-2

2021 ◽  
Vol 22 (14) ◽  
pp. 7607
Author(s):  
Theresa A. Engelmann ◽  
Lars Knudsen ◽  
Dominik H. W. Leitz ◽  
Julia Duerr ◽  
Michael F. Beers ◽  
...  
Keyword(s):  
Surface Area ◽  
Alveolar Epithelium ◽  
Cell Ultrastructure ◽  
Alveolar Epithelial Cells ◽  
Electron Microscopic Level ◽  
Type I ◽  
Electron Microscopic ◽  
Septal Wall ◽  
Ultrastructural Alterations ◽  
Alveolar Epithelial

Our previous study showed that in adult mice, conditional Nedd4-2-deficiency in club and alveolar epithelial type II (AE2) cells results in impaired mucociliary clearance, accumulation of Muc5b and progressive, terminal pulmonary fibrosis within 16 weeks. In the present study, we investigated ultrastructural alterations of the alveolar epithelium in relation to interstitial remodeling in alveolar septa as a function of disease progression. Two, eight and twelve weeks after induction of Nedd4-2 knockout, lungs were fixed and subjected to design-based stereological investigation at the light and electron microscopic level. Quantitative data did not show any abnormalities until 8 weeks compared to controls. At 12 weeks, however, volume of septal wall tissue increased while volume of acinar airspace and alveolar surface area significantly decreased. Volume and surface area of alveolar epithelial type I cells were reduced, which could not be compensated by a corresponding increase of AE2 cells. The volume of collagen fibrils in septal walls increased and was linked with an increase in blood–gas barrier thickness. A high correlation between parameters reflecting interstitial remodeling and abnormal AE2 cell ultrastructure could be established. Taken together, abnormal regeneration of the alveolar epithelium is correlated with interstitial septal wall remodeling.

Batch Precipitation of Lead Iodide

1994 ◽  
Vol 59 (6) ◽  
pp. 1301-1304
Author(s):  
Jaroslav Nývlt ◽  
Stanislav Žáček
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Crystal Size ◽  
Lead Nitrate ◽  
Lead Iodide ◽  
Constant Rate ◽  
Mean Size ◽  
The Mean

Lead iodide was precipitated by a procedure in which an aqueous solution of potassium iodide at a concentration of 0.03, 0.10 or 0.20 mol l-1 was stirred while an aqueous solution of lead nitrate at one-half concentration was added at a constant rate. The mean size of the PbI2 crystals was determined by evaluating the particle size distribution, which was measured sedimentometrically. The dependence of the mean crystal size on the duration of the experiment exhibited a minimum for any of the concentrations applied. The reason for this is discussed.

scholarly journals Effects of topical gel formulation of Ficus carica latex on cutaneous leishmaniasis induced by Leishmania major in BALB/c mice

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Ali Pouryousef ◽  
Erfan Eslami ◽  
Sepehr Shahriarirad ◽  
Sina Zoghi ◽  
Mehdi Emami ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Murine Model ◽  
Leishmania Major ◽  
Considerable Effect ◽  
Ficus Carica ◽  
Control Group ◽  
Topical Gel ◽  
The Third ◽  
Mean Size ◽  
The Mean

Abstract Objectives The current study aimed to evaluate the effects of Ficus carica latex on the treatment of cutaneous leishmaniasis (CL), induced by Leishmania major. A 5% topical gel with F. carica latex was prepared. BALB/c mice were infected by inoculation of amastigotes form of L. major. Thirty BALB/c mice were divided into five groups, where the first group was treated daily, the second group twice per day, and the third group every other day with the 5% topical gel, for 3 weeks. The sizes of the lesions were measured before and during the course of treatment. Results Although the mean size of lesions in the mice group treated with the 5% F. carica gel, especially in the group receiving daily treatment, was less than the mean size of the lesions in the control group, yet, the differences was not statistically significant (p > 0.05). The findings of the current study demonstrated that the 5% F. carica latex with a 3-week course of treatment had no considerable effect in recovery or control of CL induced by L. major in the murine model. Using higher concentration of F. carica latex and with longer treatment lengths may increase its efficacy in the treatment of CL.

scholarly journals New Methodology for Computing the Aircraft’s Position Based on the PPP Method in GPS and GLONASS Systems

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2525
Author(s):  
Kamil Krasuski ◽  
Damian Wierzbicki
Keyword(s):  
Linear Combination ◽  
Research Method ◽  
High Efficiency ◽  
Satellite System ◽  
Weighting Scheme ◽  
Measurement Technology ◽  
Dual Frequency ◽  
Weighted Mean ◽  
Mean Error ◽  
The Mean

In the field of air navigation, there is a constant pursuit for new navigation solutions for precise GNSS (Global Navigation Satellite System) positioning of aircraft. This study aims to present the results of research on the development of a new method for improving the performance of PPP (Precise Point Positioning) positioning in the GPS (Global Positioning System) and GLONASS (Globalnaja Nawigacionnaja Sputnikovaya Sistema) systems for air navigation. The research method is based on a linear combination of individual position solutions from the GPS and GLONASS systems. The paper shows a computational scheme based on the linear combination for geocentric XYZ coordinates of an aircraft. The algorithm of the new research method uses the weighted mean method to determine the resultant aircraft position. The research method was tested on GPS and GLONASS kinematic data from an airborne experiment carried out with a Seneca Piper PA34-200T aircraft at the Mielec airport. A dual-frequency dual-system GPS/GLONASS receiver was placed on-board the plane, which made it possible to record GNSS observations, which were then used to calculate the aircraft’s position in CSRS-PPP software. The calculated XYZ position coordinates from the CSRS-PPP software were then used in the weighted mean model’s developed optimization algorithm. The measurement weights are a function of the number of GPS and GLONASS satellites and the inverse of the mean error square. The obtained coordinates of aircraft from the research model were verified with the RTK-OTF solution. As a result of the research, the presented solution’s accuracy is better by 11–87% for the model with a weighting scheme as a function of the inverse of the mean error square. Moreover, using the XYZ position from the RTKLIB program, the research method’s accuracy increases from 45% to 82% for the model with a weighting scheme as a function of the inverse of the square of mean error. The developed method demonstrates high efficiency for improving the performance of GPS and GLONASS solutions for the PPP measurement technology in air navigation.

scholarly journals Mudrock Microstructure: A Technique for Distinguishing between Deep-Water Fine-Grained Sediments

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 653
Author(s):  
Shereef Bankole ◽  
Dorrik Stow ◽  
Zeinab Smillie ◽  
Jim Buckman ◽  
Helen Lever
Keyword(s):  
Grain Size ◽  
Deep Water ◽  
Sedimentary Facies ◽  
X Ray Diffraction ◽  
Weak Current ◽  
Large Area ◽  
Fine Grained ◽  
Mean Size ◽  
The Mean ◽  
Water Facies

Distinguishing among deep-water sedimentary facies has been a difficult task. This is possibly due to the process continuum in deep water, in which sediments occur in complex associations. The lack of definite sedimentological features among the different facies between hemipelagites and contourites presented a great challenge. In this study, we present detailed mudrock characteristics of the three main deep-water facies based on sedimentological characteristics, laser diffraction granulometry, high-resolution, large area scanning electron microscopy (SEM), and the synchrotron X-ray diffraction technique. Our results show that the deep-water microstructure is mainly process controlled, and that the controlling factor on their grain size is much more complex than previously envisaged. Retarding current velocity, as well as the lower carrying capacity of the current, has an impact on the mean size and sorting for the contourite and turbidite facies, whereas hemipelagite grain size is impacted by the natural heterogeneity of the system caused by bioturbation. Based on the microfabric analysis, there is a disparate pattern observed among the sedimentary facies; turbidites are generally bedding parallel due to strong currents resulting in shear flow, contourites are random to semi-random as they are impacted by a weak current, while hemipelagites are random to oblique since they are impacted by bioturbation.

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