Collagen and elastin fibers in human pulmonary alveolar walls

1988 ◽  
Vol 64 (4) ◽  
pp. 1659-1675 ◽  
Author(s):  
S. S. Sobin ◽  
Y. C. Fung ◽  
H. M. Tremer
Keyword(s):  
Transpulmonary Pressure ◽  
Collagen Fibers ◽  
Capillary Blood ◽  
Fiber Bundles ◽  
Cube Root ◽  
Inflation Pressure ◽  
Frequency Distributions ◽  
Normal Distributions ◽  
Statistical Frequency ◽  
The Mean

The morphology and morphometric data of collagen and elastin fibers in the pulmonary alveolar walls are presented. Specimens were obtained from postmortem lungs quick-frozen at specified transpulmonary pressures. Collagen was stained by silver, and elastin was stained by orcein. Photomicrographs were composed by computer. Young lungs typically show small collagen fibers that radiate from the "posts," whereas larger fiber bundles traverse the septum irrespective of capillary blood vessels. In older lungs, rings of collagen around the posts appear enlarged. Elastin bundles do not show obvious variation in pattern with age and inflation pressure. Statistical frequency distributions of the fiber width and curvature are both skewed, but the square root of the width and the cube root of the curvature have approximate normal distributions. Typically, for young lungs at transpulmonary pressure of 4 cmH2O, the mean of (width)1/2 (in micron1/2) for collagen fibers is 0.952 +/- 0.242 (SD), that of (curvature)1/3 (in micron-1/3) is 0.349 +/- 0.094. The corresponding values for elastin are 0.986 +/- 0.255 and 0.395 +/- 0.094.

An analysis of pressure-volume characteristics of the lungs

1964 ◽  
Vol 19 (1) ◽  
pp. 97-104 ◽  
Author(s):  
Eduardo Salazar ◽  
John H. Knowles
Keyword(s):  
Transpulmonary Pressure ◽  
Normal Subjects ◽  
Mean Value ◽  
Inflation Pressure ◽  
Inspiratory Capacity ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
The Mean ◽  
Volume Characteristics ◽  
Pulmonary Volume

By analysis of the retractive forces of the lungs it was found that the pressure-volume characteristics of the lungs may be expressed by an exponential function. The curve described by such expression could be fitted to the experimental data obtained in 20 normal subjects. A half-inflation pressure (h) was defined which makes possible the evaluation of the retractive forces of the lungs by a measurement independent of lung size and accounting for known curvilinearity. H is a useful index of the stiffness of the organ and it is defined as the increase in transpulmonary pressure necessary to inflate the lungs halfway to the maximal pulmonary volume from any resting level. The mean value of h for the group was 7.58 ± 2.53 cm H2O. The half-inflation pressure is independent of the level of measurement within the inspiratory capacity and it does not vary with or depend on the size of the lungs. It may therefore be a more useful expression of the retractive forces of the lungs than compliance. pulmonary retractive forces; lung stiffness; compliance half-inflation pressure and lung size; VC and half-inflation pressure; FRC and half-inflation pressure; new expression for compliance; pressure-volume curve Submitted on March 4, 1963

scholarly journals Growth and population biology of the sand-bubbler crab Scopimera crabricauda Alcock 1900 (Brachyura: Dotillidae) from the Persian Gulf, Iran

2021 ◽  
Vol 82 (1) ◽  
Author(s):  
Sana Sharifian ◽  
Vahid Malekzadeh ◽  
Ehsan Kamrani ◽  
Mohsen Safaie
Keyword(s):  
Persian Gulf ◽  
Population Biology ◽  
Slow Growth ◽  
Carapace Width ◽  
Population Data ◽  
Natural Mortality ◽  
Frequency Distributions ◽  
Iranian Coast ◽  
The Mean ◽  
The Persian Gulf

Abstract Background Dotillid crabs are introduced as one common dwellers of sandy shores. We studied the ecology and growth of the sand bubbler crab Scopimera crabricauda Alcock, 1900, in the Persian Gulf, Iran. Crabs were sampled monthly by excavating nine quadrats at three intertidal levels during spring low tides from January 2016 to January 2017. Results Population data show unimodal size-frequency distributions in both sexes. The Von Bertalanffy function was calculated at CWt = 8.76 [1 − exp (− 0.56 (t + 0.39))], CWt = 7.90 [1 − exp (− 0.59 (t + 0.40))] and CWt = 9.35 [1 − exp (− 0.57 (t + 0.41))] for males, females, and both sexes, respectively. The life span appeared to be 5.35, 5.07, and 5.26 years for males, females, and both sexes, respectively. The cohorts were identified as two age continuous groups, with the mean model carapace width 5.39 and 7.11 mm for both sexes. The natural mortality (M) coefficients stood at 1.72 for males, 1.83 for females, and 1.76 years−1 for both sexes, respectively. The overall sex ratio (1:0.4) was significantly different from the expected 1:1 proportion with male-biased. Recruitment occurred with the highest number of annual pulse once a year during the summer. Conclusions The results, which show slow growth, emphasize the necessity of proper management for the survival of the stock of S. crabricauda on the Iranian coast of the Persian Gulf.

Reference points for the length-based indicator Lmax5% for use in the assessment of data-limited stocks

2019 ◽  
Vol 76 (7) ◽  
pp. 2125-2139 ◽  
Author(s):  
Tanja Miethe ◽  
Yves Reecht ◽  
Helen Dobby
Keyword(s):  
Life Histories ◽  
Stock Assessment ◽  
Reference Points ◽  
Length Frequency ◽  
Frequency Distributions ◽  
Simulation Tools ◽  
Spawning Potential Ratio ◽  
The Mean ◽  
Commercial Sources ◽  
Length Frequency Data

Abstract In the absence of abundance indices from scientific surveys or commercial sources, reliable length frequency data from sampled commercial catches can be used to provide an indirect assessment of fishing mortality. Length-based indicators are simple metrics which describe length frequency distributions. The length-based indicator Lmax5%, the mean length of the largest 5% of individuals in the catch, combined with appropriately selected reference points, can be used to evaluate the presence of very large individuals in the catch and hence determine exploitation level. Using analytical per-recruit models, we derive reference points consistent with a spawning potential ratio of 40%. The reference points depend on the life history parameters for natural mortality, maturity, and growth (M, Lmat, L∞, k, CVL∞). Using available simulation tools, we investigate the sensitivity of the reference points to errors in these parameters and explore the usefulness of particular reference points for management purposes for stocks with different life histories. The proposed reference points are robust to uncertainty in length at first capture, Lc, and take into account the maturation schedule of a species. For those stocks with high M/k ratios (>1), Lmax5%, combined with the appropriate reference point, can be used to provide a data-limited stock assessment.

scholarly journals Evaluating the Sensitivity and Efficacy of Fungicides with Different Modes of Action Against Botryosphaeria dothidea

Plant Disease ◽  
2018 ◽  
Vol 102 (9) ◽  
pp. 1785-1793 ◽  
Author(s):  
Yingying Song ◽  
Lili Li ◽  
Chao Li ◽  
Zengbin Lu ◽  
Xingyuan Men ◽  
...  
Keyword(s):  
Field Trials ◽  
Apple Fruit ◽  
Effective Concentration ◽  
Botryosphaeria Dothidea ◽  
Control Efficacy ◽  
Frequency Distributions ◽  
Considerable Potential ◽  
Ring Rot ◽  
Fungal Plant Pathogen ◽  
The Mean

Botryosphaeria dothidea, the causal agent of apple ring rot, is an important fungal plant pathogen that can cause serious reductions in crop yield, and fungicides still play a crucial role in management. In the present study, the sensitivity of B. dothidea to fludioxonil, fluazinam, and pyrisoxazole was assessed in 162 isolates. Moreover, the protective and curative activity of the three fungicides on detached apple fruit as well as the control efficacy in the field were determined. The results showed that the mean 50% effective concentration (EC50) values (± standard deviation) were 0.01 ± 0.008, 0.04 ± 0.03, and 0.02 ± 0.01 μg ml−1, with individual EC50 values of 0.002 to 0.05, 0.003 to 0.19, and 0.005 to 0.26 μg ml−1 for fludioxonil, fluazinam, and pyrisoxazole, respectively. In addition, the frequency distributions of EC50 values were both unimodal curves. However, significant correlations (P < 0.05) were found between fludioxonil and iprodione, between fluazinam and iprodione, as well as between pyrisoxazole and difenoconazole. In field trials conducted during 2016 and 2017, the control efficacy ranged from 75.91 to 87.41% when fludioxonil was applied at 100 to 150 mg active ingredient (a.i.) kg−1, 81.90 to 85.13% when fluazinam was applied at 400 mg a.i. kg−1, and 77.43 to 80.97% when pyrisoxazole was applied at 400 mg a.i. kg−1. The control efficacy of the fungicides in storage was higher than 60%, with the exception of fluazinam. These results demonstrated that fludioxonil, fluazinam, and pyrisoxazole have considerable potential to control apple ring rot.

scholarly journals How to Distinguish Languages and Dialects

2020 ◽  
Vol 45 (4) ◽  
pp. 823-831 ◽  
Author(s):  
Søren Wichmann
Keyword(s):  
Temporal Distance ◽  
Strong Tendency ◽  
Data Sets ◽  
Language Group ◽  
Lexical Information ◽  
Normal Distributions ◽  
Mixture Of Normal Distributions ◽  
The Mean ◽  
One To One

The terms “language” and “dialect” are ingrained, but linguists nevertheless tend to agree that it is impossible to apply a non-arbitrary distinction such that two speech varieties can be identified as either distinct languages or two dialects of one and the same language. A database of lexical information for more than 7,500 speech varieties, however, unveils a strong tendency for linguistic distances to be bimodally distributed. For a given language group the linguistic distances pertaining to either cluster can be teased apart, identifying a mixture of normal distributions within the data and then separating them fitting curves and finding the point where they cross. The thresholds identified are remarkably consistent across data sets, qualifying their mean as a universal criterion for distinguishing between language and dialect pairs. The mean of the thresholds identified translates into a temporal distance of around one to one-and-a-half millennia (1,075–1,635 years).

scholarly journals EFFECTS OF PHYSICAL TRAINING ON THE MYOCARDIUM OF FEMALE LDL KNOCKOUT OVARIECTOMIZED MICE

2017 ◽  
Vol 23 (6) ◽  
pp. 441-445
Author(s):  
Ledimar Brianezi ◽  
Mara Rubia Marques ◽  
Clever Gomes Cardoso ◽  
Maria Luiza de Jesus Miranda ◽  
Fernando Luiz Affonso Fonseca ◽  
...  
Keyword(s):  
Physical Training ◽  
Volume Density ◽  
Collagen Fibers ◽  
Nuclear Volume ◽  
Control Group ◽  
Cross Sectional ◽  
Training Time ◽  
Aerobic Activity ◽  
Ovariectomized Mice ◽  
The Mean

ABSTRACT Introduction: The emergence of coronary heart disease increases with menopause, physical inactivity and with dyslipidemia. It is known that physical training promotes the improvement of cardiovascular functions. Objective: The purpose of this study was to investigate the effects of aerobic physical training on the left ventricle in female LDL knockout ovariectomized mice. Methods: Thirty animals were divided into 6 groups (n=5), namely, sedentary non-ovariectomized control; sedentary ovariectomized control; trained ovariectomized control; sedentary non-ovariectomized; sedentary ovariectomized; and trained ovariectomized. We analyzed the mean nuclear volume parameters, the cross sectional area of the myocytes, the apparent density of the capillaries, interstitium, myocytes and collagen fibers. Results: The results show that for the density of the number of nuclei, the physical activity decreased to values close to the ovariectomized control group. Regarding the mean nuclear volume and the average area of myocytes, training and ovariectomy promoted the elevation of these values but hypercholesterolemia was lower. the volume density of myocytes, hypercholesterolemia showed an increase of these values as well as the training. There was no change in the volumetric density of the capillaries and the density of collagen fibers. The training caused the decrease in the density of the interstitial volume, and the hypercholesterolemia changed to a smaller one than the control group. Conclusion: We concluded that the moderate aerobic activity or the training time used in our study were not sufficient to generate significant alterations in the hypercholesterolemic group.

scholarly journals Morphoquantitative study of the submucous plexus (of Meissner) of the jejunum-ileum of young and old guinea pigs

2011 ◽  
Vol 69 (1) ◽  
pp. 85-90 ◽  
Author(s):  
Marcelo César Zanesco ◽  
Romeu Rodrigues de Souza
Keyword(s):  
Small Intestine ◽  
Guinea Pigs ◽  
Age Groups ◽  
Collagen Fibers ◽  
Submucous Plexus ◽  
The Mean ◽  
Electronic Microscope

OBJECTIVE: To study the aging of submucous plexus of the small intestine (jejunum-ileum) of the guinea pigs from the quantitative, structural and ultrastructural perspective. METHOD: Chemical preparations of membrane of the jejunum-ileum of old and young animals with the use of light and electronic microscope. RESULTS: The ganglia of young animals presented between 1 and 56 neurons and the old animals presented from 1 to 30 neurons. The mean density of the ganglia by cm² in the young jejunum-ileum was of 551±36.89 and in the old one 413±11.86. The density of the neurons was 5011±291.11 neurons/cm² average in young animals and 2918±120.70 neurons/cm² in the old ones. The size of the neurons varied in both age groups. The collagen fibers in the ganglia of old animals they were condensed. Degenerated mitochondrias in the interior of the cell were frequent in the old animals. CONCLUSION: In submucous plexus of the jejunum-ileum there is a loss of 38% of the neurons with aging.

The use of frequency distributions in an attempt to detect host mortality induced by infections of diplostomatid metacercariae

Parasitology ◽  
1984 ◽  
Vol 89 (2) ◽  
pp. 209-220 ◽  
Author(s):  
C. R. Kennedy
Keyword(s):  
Small Sample Size ◽  
Parasite Burden ◽  
Fish Host ◽  
Small Sample ◽  
Host Age ◽  
Parasite Abundance ◽  
Frequency Distributions ◽  
Host Mortality ◽  
The Mean ◽  
Over Dispersion

SummaryFollowing recent suggestions that a peaked host age–parasite abundance curve, concomitant with a decline in the degree of dispersion of parasites in the older age classes of hosts, can provide evidence of parasite-induced host mortality, the changes in mean abundance and over-dispersion of metacercarial stages of Diplostomum spathaceum, D. gasterostei, Tylodelphys clavata and T. podicipina in relation to fish age were studied in a field locality. The mean parasite burden of D. spathaceum, D. gasterostei and T. clavata increased with host age and the maximum mean burden was found in the oldest hosts. The variance to mean ratio also increased in D. gasterostei, but decreased in the oldest hosts in D. spathaceum and T. clavata. It is concluded that this decrease could be due to parasite-induced host mortality but could equally be due to death of parasites within the host or to changes in infection rate or could be a reflection of the small sample size of the oldest fish. The mean burden of T. podicipina declined gradually with host age, but the variance to mean ratio remained constant and it is concluded that this could be explained by death of the parasites within the host. None of these data or data from other localities provided clear and unambiguous evidence of host mortality induced by heavy infections of any of the four species, although they are consistent with such mortality and do not refute such a possibility. It is concluded that it may be just as difficult to detect and unequivocally demonstrate parasite-induced host mortality in metacercarial digenean–fish host systems as in any other parasite–host systems.

The common origin of family and non-family asteroids: Implications for meteorites and NEAs

2018 ◽  
Vol 14 (S345) ◽  
pp. 281-282
Author(s):  
Stanley F. Dermott ◽  
Dan Li ◽  
Apostolos A. Christou
Keyword(s):  
Hierarchical Clustering ◽  
Common Origin ◽  
Clustering Method ◽  
Main Belt ◽  
Frequency Distributions ◽  
Size Frequency ◽  
The Family ◽  
The Common ◽  
The Mean ◽  
Asteroid Families

AbstractThe observed size-frequency distributions (SFDs) of the five major asteroid families in the Inner Main Belt (IMB), defined by Nesvorný (2015) using the Hierarchical Clustering Method (Zappala et al. 1990), are distinctly different and deviate significantly from the linear log-log relation described by Dohnanyi (1969). The existence of these differences in the SFDs, and the fact that the precursor bodies of the major families have distinctly different eccentricities and inclinations, provides an explanation for the observations that the mean sizes of both the family and the non-family asteroids are correlated with their mean proper eccentricities and anti-correlated with their mean proper inclinations. We deduce from this, and from the fact that the SFDs of the family and the non-family asteroids are almost identical, that the family and most of the non-family asteroids in the IMB have a common origin (Dermott et al. 2018).

Fractional changes in lung capillary blood volume and oxygen saturation during the cardiac cycle in rabbits

1997 ◽  
Vol 82 (5) ◽  
pp. 1668-1676 ◽  
Author(s):  
George P. Topulos ◽  
Nina R. Lipsky ◽  
John L. Lehr ◽  
Rick A. Rogers ◽  
James P. Butler
Keyword(s):  
Oxygen Saturation ◽  
Blood Volume ◽  
Lung Volume ◽  
Cardiac Cycle ◽  
Systemic Blood Pressure ◽  
Capillary Blood ◽  
Fractional Change ◽  
Pulmonary Capillary ◽  
Capillary Blood Volume ◽  
The Mean

Topulos, George P., Nina R. Lipsky, John L. Lehr, Rick A. Rogers, and James P. Butler. Fractional changes in lung capillary blood volume and oxygen saturation during the cardiac cycle in rabbits. J. Appl. Physiol. 82(5): 1668–1676, 1997.—Changes in local pulmonary capillary blood volume (Vc) and oxygen saturation (S) have been difficult to measure in live animals. By utilizing the differences in absorption of light at two wavelengths (650 and 800 nm), we estimated the fractional change in Vc and S during the course of the cardiac cycle in eight anesthetized, ventilated rabbits at low and high lung volumes. Observations were made of the pattern of diffusely backscattered light, from an ∼1-cm3 volume of lung illuminated with a point source placed on the pleural surface through a thoracotomy. At low lung volume, the fractional change in Vc was ∼13%, the change in S was ∼4.6%, and the mean S was close to 77%. The fluctuations in Vc and S lagged behind peak systemic blood pressure by about one-fifth and three-fifths of a cycle, respectively. At high lung volume, there were no important fluctuations in Vc or S, and the mean S was ∼82%. These results are consistent with fluctuations in pulmonary capillary pressure and gas exchange over the cardiac cycle, and with decreasing capillary compliance with increasing lung volume.

Sign in / Sign up

Export Citation Format

Share Document