scholarly journals Confinement Related Phenomena in MoS 2 Tubular Structures Grown from Vapour Phase

Author(s):  
Maja Remskar ◽  
Andreas K. Hüttel ◽  
Tatiana V. Shubina ◽  
Alan Seabaugh ◽  
Sara Fathipour ◽  
...  
Author(s):  
G. D. Gagne ◽  
M. F. Miller ◽  
D. A. Peterson

Experimental infection of chimpanzees with non-A, non-B hepatitis (NANB) or with delta agent hepatitis results in the appearance of characteristic cytoplasmic alterations in the hepatocytes. These alterations include spongelike inclusions (Type I), attached convoluted membranes (Type II), tubular structures (Type III), and microtubular aggregates (Type IV) (Fig. 1). Type I, II and III structures are, by association, believed to be derived from endoplasmic reticulum and may be morphogenetically related. Type IV structures are generally observed free in the cytoplasm but sometimes in the vicinity of type III structures. It is not known whether these structures are somehow involved in the replication and/or assembly of the putative NANB virus or whether they are simply nonspecific responses to cellular injury. When treated with uranyl acetate, type I, II and III structures stain intensely as if they might contain nucleic acids. If these structures do correspond to intermediates in the replication of a virus, one might expect them to contain DNA or RNA and the present study was undertaken to explore this possibility.


Author(s):  
C. N. Sun ◽  
J. J. Ghidoni

Endothelial cells in longitudinal and cross sections of aortas from 3 randomly selected “normal” mongrel dogs were studied by electron microscopy. Segments of aorta were distended with cold cacodylate buffered 5% glutaraldehyde for 10 minutes prior to being cut into small, well oriented tissue blocks. After an additional 1-1/2 hour period in glutaraldehyde, the tissue blocks were well rinsed in buffer and post-fixed in OsO4. After dehydration they were embedded in a mixture of Maraglas, D.E.R. 732, and DDSA.Aldehyde fixation preserves the filamentous and tubular structures (300 Å and less) for adequate demonstration and study. The functional significance of filaments and microtubules has been recently discussed by Buckley and Porter; the precise roles of these cytoplasmic components remains problematic. Endothelial cells in canine aortas contained an abundance of both types of structures.


Author(s):  
J. A. Nowell ◽  
J. Pangborn ◽  
W. S. Tyler

Leonardo da Vinci in the 16th century, used injection replica techniques to study internal surfaces of the cerebral ventricles. Developments in replicating media have made it possible for modern morphologists to examine injection replicas of lung and kidney with the scanning electron microscope (SEM). Deeply concave surfaces and interrelationships to tubular structures are difficult to examine with the SEM. Injection replicas convert concavities to convexities and tubes to rods, overcoming these difficulties.Batson's plastic was injected into the renal artery of a horse kidney. Latex was injected into the pulmonary artery and cementex in the trachea of a cat. Following polymerization the tissues were removed by digestion in concentrated HCl. Slices of dog kidney were aldehyde fixed by immersion. Rat lung was aldehyde fixed by perfusion via the trachea at 30 cm H2O. Pieces of tissue 10 x 10 x 2 mm were critical point dried using CO2. Selected areas of replicas and tissues were coated with silver and gold and examined with the SEM.


Author(s):  
Matias Pardo ◽  
Malcolm Slifkin ◽  
Leonard Merkow ◽  
Marie Sanchez

The simian adenoviruses SV20, SV30 and SA7 have been found to be oncogenic in the Syrian hamster. The growth characteristics and replicative cycle of these viruses in tissue culture therefore appeared appropriate to investigate. Cesium chloride purified simian adenovirus with an infectivity titer of 100 TCID50, was inoculated into monolayers of LLC-MK2 cells. Cells were fixed in osmium tetroxide and embedded for ultrastructural studies at 1, 3, 6, 9, 18, 24, 48, 72, 120 and 192 hours post-infection.At the first hour post-infection, virus particles were adsorbed to the plasmalemma and found within the peripheral cytoplasm of many LLC-MK2 cells (Fig. 1). Although the first detection of infectious virus occurred at 14 hours and infectivity titers did not reach a maximum until 30 hours, intranuclear virus particles were observed by 3 hours in typical adenovirus crystalline array (Fig. 2) by means of electron microscopy. These typical honeycomb arrayed virus particles at 3 hours provided evidence of significant replication in approximately 5 percent of tissue culture cells examined. Simultaneously, a classical nuclear inclusion manifested by peripheral condensation of nuclear chromatin was evident by light microscopy. As early at 6 to 9 hours, unusual intranuclear concentric membranes formed “tubes” which contained linear arranged virus particles (Fig. 3). In transverse or tangential sections, these “tubes” appeared cochlear-like in shape. In longitudinal section, these intranuclear tubular structures contained individual virus particles at various stages of maturation in a linear arranged order. This arrangement resembled “peas in a pod”.


Author(s):  
A. Carlsson ◽  
J.-O. Malm ◽  
A. Gustafsson

In this study a quantum well/quantum wire (QW/QWR) structure grown on a grating of V-grooves has been characterized by a technique related to chemical lattice imaging. This technique makes it possible to extract quantitative information from high resolution images.The QW/QWR structure was grown on a GaAs substrate patterned with a grating of V-grooves. The growth rate was approximately three monolayers per second without growth interruption at the interfaces. On this substrate a barrier of nominally Al0.35 Ga0.65 As was deposited to a thickness of approximately 300 nm using metalorganic vapour phase epitaxy . On top of the Al0.35Ga0.65As barrier a 3.5 nm GaAs quantum well was deposited and to conclude the structure an additional approximate 300 nm Al0.35Ga0.65 As was deposited. The GaAs QW deposited in this manner turns out to be significantly thicker at the bottom of the grooves giving a QWR running along the grooves. During the growth of the barriers an approximately 30 nm wide Ga-rich region is formed at the bottom of the grooves giving a Ga-rich stripe extending from the bottom of each groove to the surface.


Planta Medica ◽  
2007 ◽  
Vol 73 (09) ◽  
Author(s):  
L Nedorostova ◽  
P Kloucek ◽  
M Stolcova ◽  
L Kokoska

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