Microscopic Airway Reopening Through Cascades of Plugs Ruptures

2009 ◽  
Author(s):  
M. Baudoin ◽  
Y. Song ◽  
C. N. Baroud ◽  
P. Manneville
Keyword(s):  
Flow Resistance ◽  
First Generation ◽  
Human Lung ◽  
Careful Analysis ◽  
Initial Distribution ◽  
Width Ratio ◽  
Airway Reopening ◽  
Successive Generations ◽  
Binary Network ◽  
Lung Airways

The inner surface of lung airways is covered by a thin layer of mucus whose thickness is usually about 2 or 3% of the total radius of the duct. However certain diseases like asthma, chronic bronchitis or allergies can induce a hypersecretion of mucus, leading to the formation of liquid plugs which occlude the airways. These plugs can considerably alter the distribution of air during the breathing cycle. It is therefore fundamental to understand the propagation of air in the presence of such plugs and in particular airway reopening. Some studies have been performed on real lungs but there was no visualization of the airways, and only information at the entrance was reported. The purpose of this experimental work is to create a synthetic network, reproducing only the main features of the lung airways, to visualize and understand the physics of airway reopening. The human lung is made of about 24 generations with diameters ranging from about 2 cm for the trachea to 100 μm for the smallest ones. As a consequence, the physics is very different for the first and the last generations. The present work focuses on the last micrometric generations for which inertia and gravity can be neglected (small Reynolds and Bond numbers). For this purpose a binary network made of PDMS was designed and fabricated. It is composed of 6 generations with a width of 700 μm for the first generation and a width ratio of 0.8 between the branches of successive generations. A random initial distribution of plugs is inserted inside this network by using syringe pumps and finally some air is introduced inside the airways. The reopening of the network takes place through a series of cascades of plugs ruptures. A single cascade can be explained by a simple model, based on the flow resistance of the plugs and the liquid deposited on the walls. The correlation between successive cascades is extracted from a careful analysis of the data. This study improves considerably our understanding of cascades of plug ruptures, which might be valuable to enhance the treatment of such diseases.

Branching pattern of airways and air spaces of a single human terminal bronchiole

1975 ◽  
Vol 38 (6) ◽  
pp. 983-989 ◽  
Author(s):  
J. E. Hansen ◽  
E. P. Ampaya ◽  
G. H. Bryant ◽  
J. J. Navin
Keyword(s):  
Young Adult ◽  
Polyurethane Foam ◽  
First Generation ◽  
Human Lung ◽  
Branching Pattern ◽  
Serial Sections ◽  
Adult Human ◽  
Three Generations ◽  
Terminal Bronchiole ◽  
Adult Human Lung

A polyurethane-foam enlarged reconstruction was made from serial sections of a portion of young adult human lung parenchyman. Study of the progeny of a terminal bronchiole disclosed three generations of respiratory bronchioles and an irregular branching pattern of eight generations of alveolar ducts. Sacs and alveoli arose from the lateral and distal aspects of all generations of ducts. There were an average of 3.5 alveoli per sac. Considering the terminal bronchiole as the first generation branch of the acinus, over 60 per cent of the alveoli counted and predicted were members of the 10–12th generations. The acinus contained one terminal bronchiole and approximately 14 respiratory bronchioles, 1,200–1,500 ducts, 2,500–4,500 sacs, and 14,000–20,000 alveoli.

Temperature-Growth Relations and Genetic Diversity of A2 Mating-Type Isolates of Phytophthora cinnamomi in Australia

1974 ◽  
Vol 22 (2) ◽  
pp. 231 ◽  
Author(s):  
CJ Shepherd ◽  
BH Pratt
Keyword(s):  
Growth Rate ◽  
First Generation ◽  
Phytophthora Cinnamomi ◽  
Phytophthora Species ◽  
Temperature Growth ◽  
Field Isolates ◽  
Place Of Origin ◽  
Successive Generations ◽  
Cardinal Temperatures ◽  
Range Of Values

Determinations of cardinal temperatures for growth on various media of 50 Australian isolates of Phytophthova cinnamomi showed that growth did not occur outside the range 5-35°C. The range of temperatures at which growth optima occurred varied according to the isolate and medium used and encompassed the whole range of values reported by overseas authors. Growth rates of 361 isolates on corn meal agar at 25°C varied within the range 4.7-10.5 mm/day. There was no correlation between optimum temperature and whether isolates were slow- or fastgrowing or their place of origin. Fast-growing isolates (6-11 mm/day) were obtained from all States, but slower-growing isolates (<6 mm/day) were obtained only from southern and western regions of Australia. Populations from different regions of Australia exhibited different growth rate parameters. The variability of mycelial isolates in culture was studied by examining differences in growth rate among replicated parent, single-zoospore, single-zoosporangium and single terminal-hyphal isolates. Extensive variation was found among first generation single-zoospore progenies of field isolates, with lesser variation among progeny of single zoosporangia, terminal hyphal cultures and second and third generation zoospore derivatives. The origin of this variation is discussed and it is suggested that field isolates are heterokaryotic, since zoospores proved to be predominantly uninucleate. When various Phytophthora species were incubated at temperatures above those at which growth was possible and then returned to 25°C, their subsequent ability to resume growth depended on the particular time-temperature combination used. Considerable variation of response was found among a number of isolates of P. cinnamomi and, following the establishment of single zoospore isolates, the potential variability of field isolates was shown to persist through successive generations of zoospore propagation. It is suggested that a cytoplasmic mechanism of inheritance may be responsible for this variation.

Reassessing the Generational Disparity in Immigrant Offending: A Within-family Comparison of Involvement in Crime

2019 ◽  
Vol 56 (6) ◽  
pp. 851-887 ◽  
Author(s):  
Bianca E. Bersani ◽  
Adam W. Pittman
Keyword(s):  
First Generation ◽  
Second Generation ◽  
Well Being ◽  
Foreign Born ◽  
Data Set ◽  
The Difference ◽  
Successive Generations ◽  
Offending Patterns ◽  
High Degree ◽  
Parent Child

Objective:This study reassesses the generational disparity in immigrant offending. Patterns and predictors of offending are compared using traditional peer-based models and an alternative within-family (parent–child dyad) model.Method:The National Longitudinal Survey of Youth (1979; NLSY79) and NLSY-Child and Young Adult (NLSY_CYA) data are merged to create an intergenerational data set to compare generational disparities in immigrant offending across peers and within families. Differences in self-reported offending (prevalence and variety) by immigrant generation are assessed using a combination of descriptive analyses (χ2and analysis of variance) and regression models.Results:While NLSY_CYA children generally are at a greater risk of offending compared with the NLSY79 mothers, the difference in offending is greatest between first-generation mom and second-generation child dyads. Disparities in offending are driven in large part by exceedingly low levels of offending among first-generation immigrants.Conclusion:Although the factors driving an increase in offending between parent–child generations are not unique to immigrants, they are amplified in immigrant families. Whereas the second generation is remarkably similar to their U.S.-born counterparts in terms of their involvement in crime, suggesting a high degree of swift integration, the greater involvement in crime among the children of immigrants compared to their foreign-born mothers suggests a decline in well-being across successive generations.

Birthcoat–adult fleece relationship: a study of kemp succession in a coarse wool breed of sheep

1979 ◽  
Vol 92 (2) ◽  
pp. 427-436 ◽  
Author(s):  
R. A. Guirgis ◽  
H. M. H. El Gabbas ◽  
E. S. E. Galal ◽  
K. E. Ghoneim
Keyword(s):  
Fibre Type ◽  
First Generation ◽  
General Trend ◽  
Early Stage ◽  
Present Material ◽  
Saddle Type ◽  
Early Survival ◽  
Successive Generations ◽  
Shoulder Position ◽  
Staple Length

SummaryThe birthcoat of coarse wool Barki lambs was investigated at the age of 1–1·5 months. Lambs were covered when they were 2 months old to study kemp succession, and some other adult fleece traits, at the age of 16 months in relation to the birthcoat fibre type arrays. Samples were taken from three dorsal and three lateral positions. The average halo hair grade was 5·45% and the coarse fibre type array, plateau, contributed 64·7% of the birthcoat arrays, the rest were of the less coarse, saddle, type. Halo hair grade and fibre type arrays showed an antero-posterior gradient, increasing in score and coarseness posteriorly.All halo hairs, 41·9% of super sickles and 22·6% of hairy tip curly tip fibres were shed as first generation kemp (G1 Curly tip and histerotrich fibres shed the least and they contributed the majority of the total persistent fibres. When pre-curly tip fibres increased in the birthcoat samples, that was followed by more kemp in the adult fleece.The average G1% kemp was 4·43. Kemp decreased in subsequent generations, values were 34·50 and 8·37 for G2/G1% and G1/%, respectively. G1%, and G2/G1% kemp showed a general trend of an increase towards posterior positions; the shoulder position was an exception to that.Coarse birthcoat fibre type arrays, plateau, were followed by more kemp in G1% and in successive generations than were the less coarse, saddle, arrays. High values of G2/G1% kemp were followed by significantly high G3/G1% kemp. Within animals, there was a significant correlation (P < 0·01) between halo hair grade and G1% kemp.Staple length showed a tendency to increase towards posterior positions and females showed slightly longer staples than those of males. A slight trend of decrease in staple length was observed following the less coarse array, saddle, as compared with that which followed the coarse array, plateau.For selection against kemp at an early stage, though birthcoat halo hair grade was positively correlated with G1% kemp, a high halo hair grade is essential for the lamb's early survival, hence fibre type arrays should be considered in selection. Less coarse birthcoat arrays, saddle in the present material, and a high, within array, curly tip: pre-curly tip ratio would be preferrable.

scholarly journals Luther i den moderna lutherdomens tjänst

2022 ◽  
Vol 97 (4) ◽  
Author(s):  
Leif Svensson
Keyword(s):  
Nineteenth Century ◽  
First Generation ◽  
Modern Society ◽  
Careful Analysis ◽  
Considerable Distance ◽  
High Regard

There are plenty of misconceptions about how the Luther Renais­sance in Sweden relates to Albrecht Ritschl and nineteenth-century German Luther research. This article sheds new light on the importance of Ritschl's groundbreaking Luther interpretation to the first generation of the Swedish Luther Renaissance, as represented by its leading voices – Einar Billing and Nathan Söderblom. I demonstrate that there are substantial similarities between how Ritschl, Billing, and Söderblom approach and make use of Luther's thought. They all combine a careful analysis of Luther's theology with an interest in understanding his role in history. And despite their high regard of Luther as the great Protestant reformer, Ritschl, Billing, and Söderblom at times show a considerable distance to his thinking. It is also evident that they found solutions to contemporary questions and challenges in Luther's writings. Their constructive use of Luther is, I further argue, closely related to a positive reception of histor­ical criticism and an ambition to make Lutheranism relevant to modern society. This to a large extent explains why Ritschl, Billing, and Söderblom have a freer attitude towards Luther than many of their Lutheran col­leagues, and also why they emphasize those aspects of his theology that they consider especially fruitful for modern society.

scholarly journals Modelling Hygroscopic Particle Growth in Human Lung Airways

1997 ◽  
Vol 41 (inhaled particles VIII) ◽  
pp. 60-64 ◽  
Author(s):  
G. M. Schum ◽  
R. F. Phalen
Keyword(s):  
Human Lung ◽  
Particle Growth ◽  
Lung Airways

scholarly journals Quality deterioration of mass reared offsprings of Bracon hebetor in successive generations

2016 ◽  
Vol 13 (2) ◽  
pp. 1-12
Author(s):  
MS Alam ◽  
MZ Alam ◽  
SN Alam ◽  
MRU Miah ◽  
MIH Mian ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Significant Variation ◽  
First Generation ◽  
Galleria Mellonella ◽  
Progeny Production ◽  
Bracon Hebetor ◽  
Sixth Generation ◽  
Male Sex ◽  
Successive Generations ◽  
Wax Moth

A study was undertaken to determine the generation-wise parasitizing efficiency of mass reared Bracon hebetor on wax moth (Galleria mellonella). Two experiments were conducted to achieve the objectives. In the first experiment, the host larvae and parasitoid were released in the field micro plot during first generation and reared in the laboratory in subsequent generations. In another experiment, all generations were developed in the laboratory. In the first experiment, generation showed significant variation on sex ratio of adult progeny production. The male sex ratio increased with the range of 62.89 to 74.58% and female sex ratio declined ranging from 39 to 25% with the advancement of generations. The percent parasitization and adult progeny production was not influenced appreciably with the progress of generation. In the second experiment parasitization and adult progeny production did not vary significantly in successive generations. However there was a decreasing trend in parasitization from 95 to 55% by Bracon hebetor and adult progeny production by 47.5 to 15.5 adultsfemale-110 larvae-1 over generation. The sex ratio of adult progeny was significantly influenced by inbreed generation in laboratory reared population. Female decrease in sex ratio from first to sixth generation was 39.25 to 16.88%.SAARC J. Agri., 13(2): 1-12 (2015)

Dynamic flow in a realistic model of the upper human lung airways

2007 ◽  
Vol 43 (2-3) ◽  
pp. 411-423 ◽  
Author(s):  
Katrin Adler ◽  
Christoph Brücker
Keyword(s):  
Human Lung ◽  
Realistic Model ◽  
Dynamic Flow ◽  
Lung Airways

Hybridization between Invasive Populations of Dalmatian Toadflax (Linaria dalmatica) and Yellow Toadflax (Linaria vulgaris)

2009 ◽  
Vol 2 (4) ◽  
pp. 369-378 ◽  
Author(s):  
Sarah M. Ward ◽  
Caren E. Fleischmann ◽  
Marie F. Turner ◽  
Sharlene E. Sing
Keyword(s):  
First Generation ◽  
Seed Morphology ◽  
Width Ratio ◽  
Putative Hybrid ◽  
Phenotypic Traits ◽  
Parent Species ◽  
Linaria Dalmatica ◽  
Yellow Toadflax ◽  
Hybrid Plants ◽  
Dalmatian Toadflax

AbstractAlthough there is evidence that interspecific hybridization can initiate invasion by nonnative plants, there are few documented examples of novel hybridization events between introduced plant species already exhibiting invasive behavior. We conducted morphometric and molecular analyses of toadflax plants with intermediate morphology found at two sites in Montana, which were co-invaded by yellow toadflax and Dalmatian toadflax. Field-collected putative hybrid plants had intermediate morphometric scores (mean 0.47, on a scale of 0.0 = indistinguishable from Dalmatian toadflax to 1.0 = indistinguishable from yellow toadflax) for a suite of phenotypic traits that differentiate the parent species (leaf length : width ratio, growth form, seed morphology, inflorescence type, and ventral petal shape). Inter-simple sequence repeat (ISSR) analysis of a subset of these putative hybrids revealed combinations of species-diagnostic bands, confirming the presence of DNA from both parent species. Controlled interspecific hand-pollinations generated viable first generation (F1) hybrid plants that also had intermediate morphometric scores (mean 0.46) and a mix of species-diagnostic ISSR bands from both parents. The hand-generated F1hybrids crossed readily with both parent species to produce viable first generation backcrossed (BC1) plants. Our results confirm that hybridization is occurring between invasive populations of yellow toadflax and Dalmatian toadflax, and that the hybrid progeny are viable and fertile. This example of hybridization between alien congeners is of concern as the parent taxa are already known to be highly invasive. Further research is needed to assess the invasive potential of hybrid toadflax populations, and the likelihood of introgressive trait transfer between the parent species.

Static analysis of hydrostatic conical bearings using flow resistance network method

2014 ◽  
Vol 66 (3) ◽  
pp. 411-423 ◽  
Author(s):  
Shun-Te Hsiao ◽  
Yuan Kang ◽  
Shyh-Ming Jong ◽  
Hsing-Han Lee ◽  
De-Xing Peng ◽  
...  
Keyword(s):  
Flow Resistance ◽  
Load Capacity ◽  
Design Parameters ◽  
Width Ratio ◽  
Static Stiffness ◽  
Content Type ◽  
Single Action ◽  
Network Method ◽  
Conical Bearing ◽  
Land Width

Purpose – This paper aims to study the static characteristics of the hydrostatic conical journal bearings by utilizing single-action membrane restrictors to compensate the working pressures of recesses. Design/methodology/approach – The flow resistance network method is used to analyze the influences of load capacity and static stiffness of bearing with the design parameters, including the number of recesses, radial eccentricity ratio, axial displacement ratio, restriction constant, membrane compliance, length-diameter ratio, circumferential land width ratio, axial land width ratio and half of cone angle. Findings – This study shows the infinite stiffness of the oil produced in the first and second recesses while single-action membrane restriction constant of 2 and 3, respectively, as well as in the fourth recess while single-action membrane restriction constant of 0.01 and 0.1, respectively. Research limitations/implications – This article provides the hydrostatic conical bearings in static and unbiased states for analyses of design parameters. The analyses ignore dynamic pressure effect and do not use the Reynolds equation, and assuming that each oil recesses pressure is constant. Practical implications – The influences of the design parameters including the number of recesses, membrane restriction, membrane compliance, length-diameter ratio, half of con-angle, circumferential land width ratio, and axial land width ratio are discussed to the load capacity and static stiffness of conical bearing. Originality/value – Based on the characteristics of the conical bearing through analysis, this article suggests the front bearing with hard membrane restrictor (capillary) and the back bearing with soft membrane restrictor are the most appropriate for axial stiffness.

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