scholarly journals Three-Dimensional Structure and Disposition of the Air Conducting and Gas Exchange Conduits of the Avian Lung: The Domestic Duck (Cairina moschata)

ISRN Anatomy ◽  
2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
A. N. Makanya ◽  
B. M. Kavoi ◽  
V. Djonov

The anatomy of the domestic duck lung was studied macroscopically, by casting and by light, transmission, and scanning electron microscopy. The lung had four categories of secondary bronchi (SB), namely, the medioventral (MV, 4-5), laterodorsal (LD, 6–10), lateroventral (LV, 2–4), and posterior secondary bronchi (PO, 36–44). The neopulmonic parabronchi formed an intricate feltwork on the ventral third of the lung and inosculated those from the other SB. The lung parenchyma was organized into cylindrical parabronchi separated by thin septa containing blood vessels. Atria were shallow and well-fortified by epithelial ridges reinforced by smooth muscle bundles and gave rise to 2–6 elongate infundibulae. Air capillaries arose either directly from the atria or from infundibulae and were tubular or globular in shape with thin interconnecting branches. The newly described spatial disposition of the conducting air conduits closely resembles that of the chicken. This remarkable similarity between the categories, numbers, and 3D arrangement of the SB in the duck and chicken points to a convergence in function-oriented design. To illuminate airflow dynamics in the avian lung, precise directions of airflow in the various categories of SB and parabronchi need to be characterized.

2014 ◽  
Vol 70 (11) ◽  
pp. 1054-1056 ◽  
Author(s):  
Qiang Li ◽  
Hui-Ting Wang

A new cadmium dicyanamide complex, poly[tetramethylphosphonium [μ-chlorido-di-μ-dicyanamido-κ4N1:N5-cadmium(II)]], [(CH3)4P][Cd(NCNCN)2Cl], was synthesized by the reaction of tetramethylphosphonium chloride, cadmium nitrate tetrahydrate and sodium dicyanamide in aqueous solution. In the crystal structure, each CdIIatom is octahedrally coordinated by four terminal N atoms from four anionic dicyanamide (dca) ligands and by two chloride ligands. The dicyanamide ligands play two different roles in the building up of the structure; one role results in the formation of [Cd(dca)Cl]2building blocks, while the other links the building blocks into a three-dimensional structure. The anionic framework exhibits a solvent-accessible void of 673.8 Å3, amounting to 47.44% of the total unit-cell volume. The cavities in the network are occupied by pairs of tetramethylphosphonium cations.


IUCrData ◽  
2019 ◽  
Vol 4 (8) ◽  
Author(s):  
Patrick Butler

The title tetranuclear stannoxane, [Sn4(C6H5)8(C6H4NO3)4O2]·1.5CHCl3·solvent, crystallized with two independent complex molecules, A and B, in the asymmetric unit together with 1.5 molecules of chloroform. There is also a region of disordered electron density, which was corrected for using the SQUEEZE routine [Spek (2015). Acta Cryst. C71, 9–18]. The oxo-tin core of each complex is in a planar `ladder' arrangement and each Sn atom is fivefold SnO3C2 coordinated, with one tin centre having an almost perfect square-pyramidal coordination geometry, while the other three Sn centres have distorted shapes. In the crystal, the complex molecules are arranged in layers, composed of A or B complexes, lying parallel to the bc plane. The complex molecules are linked by a number of C—H...O hydrogen bonds within the layers and between the layers, forming a supramolecular three-dimensional structure.


1988 ◽  
Vol 89 (2) ◽  
pp. 243-252
Author(s):  
L.M. Stoilov ◽  
J.S. Zlatanova ◽  
A.P. Vassileva ◽  
M.G. Ivanchenko ◽  
C.P. Krachmarov ◽  
...  

Plant nuclei have been studied with respect to the three-dimensional structure of DNA. Nucleoids derived from nuclei by non-ionic detergent and high salt treatment were analysed by sedimentation in a series of sucrose gradients containing increasing amounts of the intercalating agent ethidium bromide. In addition the nucleoid sedimentation behaviour was investigated following gamma irradiation. The results show that plant DNA is supercoiled, as is the DNA from the other eukaryotes studied, and contains approximately the same concentration of superhelical turns but probably relatively fewer DNA superhelical loops. The plant nuclear populations in all cases studied give rise to two distinct nucleoid bands. These have been characterized by electron microscopy and by their DNA and protein content. The possible origin of the two bands is discussed.


2009 ◽  
Vol 65 (3) ◽  
pp. m118-m120
Author(s):  
Olha Sereda ◽  
Helen Stoeckli-Evans

The title coordination polymer, [Cd3Co2(CN)12(C2H8N2)4]n, has an infinite two-dimensional network structure. The asymmetric unit is composed of two crystallographically independent CdIIatoms, one of which is located on a twofold rotation axis. There are two independent ethylenediamine (en) ligands, one of which bis-chelates to the Cd atom that sits in a general position, while the other bridges this Cd atom to that sitting on the twofold axis. The Cd atom located on the twofold rotation axis is linked to four equivalent CoIIIatomsviacyanide bridges, while the Cd atom that sits in a general position is connected to three equivalent CoIIIatomsviacyanide bridges. In this way, a series of trinuclear, tetranuclear and pentanuclear macrocycles are linked to form a two-dimensional network structure lying parallel to thebcplane. In the crystal structure, these two-dimensional networks are linkedviaN—H...N hydrogen bonds involving an en NH2H atom and a cyanide N atom, leading to the formation of a three-dimensional structure. This coordination polymer is only the second example involving a cyanometallate where the en ligand is present in both chelating and bridging coordination modes.


Biologia ◽  
2009 ◽  
Vol 64 (6) ◽  
Author(s):  
Paulína Gálfiová ◽  
Ivan Varga ◽  
Martin Kopáni ◽  
Peter Michalka ◽  
Jana Michalková ◽  
...  

AbstractThe representation of microcirculation can be approached in several ways. One of the possibilities is to represent the endothelium (endothelial or sinus lining cells) and their basement membrane on the basis of detecting the known components and the expression of the surface antigenes by the methods of immuno-, enzyme- or lectino-histochemical analysis, or by staining or impregnation histological methods. The other possibility is the examination of samples by transmission and scanning electron microscopy. For three-dimensional demonstration corrosion casts techniques or laser scanning confocal microscopy can be used. In this paper we describe the survey of immuno-, enzyme- and lectino-histochemical characteristics of selected components of microcirculation and our own results of its demonstration in human spleen.


Author(s):  
Runqing Ou ◽  
Robert J. Samuels ◽  
Rosario A. Gerhardt

In this paper the influence of anisotropic molecular structure on the three dimensional electrical properties of both poly(phenylene vinylene), (PPV), and polyaniline, (PANI) oriented films is investigated. The anisotropic structure of the stretched PPV and PANI EB films were examined using a modified waveguide coupler while three dimensional impedance spectroscopy measurements were made using specially designed test fixtures that allowed the in-plane as well as the through-plane impedance to be measured. The unstretched PANI EB film has a random orientation and one-way stretching leads to a uniaxial structure. The unstretched PPV film, on the other hand, was found to have a highly planar structure and oneway stretching converts the planar structure to a uniaxial structure. Impedance measurements were made on PANI after it was doped with HCl while PPV films were measured in the undoped state. For HCl-doped PANI films, the conductivity along the stretch direction was found to increase with orientation. For undoped PPV films, the conductivity through the film thickness direction decreased with increasing orientation. For both polymers, the in-plane conductivity was significantly greater than the through-plane conductivity.


2015 ◽  
Vol 1744 ◽  
pp. 235-240 ◽  
Author(s):  
Jukka Kuva ◽  
Mikko Voutilainen ◽  
Antero Lindberg ◽  
Joni Parkkonen ◽  
Marja Siitari-Kauppi ◽  
...  

ABSTRACTIn order to better understand the micrometer-scale structure of rock and its transport properties which arise from it, seven monomineral samples from two sites (Olkiluoto and Sievi, Finland) were studied with micro- and nanotomography and scanning electron microscopy. From the veined gneiss of Olkiluoto we studied biotite, potassium feldspar, plagioclase (composition of oligoclase) and cordierite, and from Sievi tonalite biotite and two grains of plagioclase (albite). These minerals were the main minerals of these samples. Samples were carefully separated and selected using heavy liquid separation and stereomicroscopy, their three dimensional structure was imaged using X-ray tomography, and their precise mineral composition was determined using scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDS). The micrometer-scale mineral structure of these samples was observed together with their pores and fissures, and alteration effects were identified whenever applicable. Nanotomography combined with SEM analysis was concluded to be a good tool for analyzing effects of alteration in monomineral samples.


Sign in / Sign up

Export Citation Format

Share Document