scholarly journals Cytotype distribution at a diploid-tetraploid contact zone inChamerion(Epilobium)angustifolium(Onagraceae)

1998 ◽  
Vol 85 (12) ◽  
pp. 1688-1694 ◽  
Author(s):  
Brian C. Husband ◽  
Douglas W. Schemske
Keyword(s):  
Contact Zone ◽  
Epilobium Angustifolium ◽  
Cytotype Distribution

scholarly journals Cytotype distribution at a diploid–hexaploid contact zone in Aster amellus (Asteraceae)

2012 ◽  
Vol 110 (5) ◽  
pp. 1047-1055 ◽  
Author(s):  
S. Castro ◽  
J. Loureiro ◽  
T. Procházka ◽  
Z. Münzbergová
Keyword(s):  
Contact Zone ◽  
Cytotype Distribution

scholarly journals Cytotype distribution patterns, ecological differentiation, and genetic structure in a diploid-tetraploid contact zone ofCardamine amara

2015 ◽  
Vol 102 (8) ◽  
pp. 1380-1395 ◽  
Author(s):  
Judita Zozomová-Lihová ◽  
Iva Malánová-Krásná ◽  
Petr Vít ◽  
Tomáš Urfus ◽  
Dušan Senko ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Contact Zone ◽  
Distribution Patterns ◽  
Ecological Differentiation ◽  
Cytotype Distribution

Resolution of Channels in the Exine by Translocation of Colloidal Iron

1971 ◽  
Vol 29 ◽  
pp. 352-353
Author(s):  
John R. Rowley
Keyword(s):  
Phosphate Buffer ◽  
Pollen Development ◽  
Osmium Tetroxide ◽  
Pollen Grains ◽  
Deionized Water ◽  
Colloidal Iron ◽  
Fixed Material ◽  
Epilobium Angustifolium ◽  
Untreated Material ◽  
Microspore Mitosis

The morphology of the exine of many pollen grains, at the time of flowering, is such that one can suppose that transport of substances through the exine occurred during pollen development. Holes or channels, microscopic to submicroscopic, are described for a large number of grains. An inner part of the exine of Epilobium angustifolium L. and E. montanum L., which may be referred to as the endexine, has irregularly shaped channels early in pollen development although by microspore mitosis there is no indication of such channeling in chemically fixed material. The nucleus in microspores used in the experiment reported here was in prophase of microspore mitosis and the endexine, while lamellated in untreated grains, did not contain irregularly shaped channels. Untreated material from the same part of the inflorescence as iron treated stamens was examined following fixation with 0.1M glutaraldehyde in cacodylate-HCl buffer at pH 6.9 (315 milliosmoles) for 24 hrs, 4% formaldehyde in phosphate buffer at pH 7.2 (1,300 milliosmoles) for 12 hrs, 1% glutaraldehyde mixed with 0.1% osmium tetroxide for 20 min, osmium tetroxide in deionized water for 2 hrs and 1% glutaraldehyde mixed with 4% formaldehyde in 0.1M cacodylate-HCl buffer at pH 6.9 for two hrs.

Antioxidant and antimicrobial activity of willow herb (Epilobium angustifolium L.)

Planta Medica ◽  
2008 ◽  
Vol 74 (09) ◽  
Author(s):  
I Kosalec ◽  
M Zovko ◽  
K Sankovic ◽  
D Kremer ◽  
S Pepeljnjak
Keyword(s):  
Antimicrobial Activity ◽  
Epilobium Angustifolium ◽  
Antioxidant And Antimicrobial Activity

Tire Treadwear — A Comprehensive Evaluation of the Factors: Generic Type, Aspect Ratio, Tread Pattern, and Tread Composition Part IV: Laboratory Measurement of Mechanical Properties and Mechanical Actions of Tires Relating to Treadwear

1986 ◽  
Vol 14 (4) ◽  
pp. 264-291
Author(s):  
K. L. Oblizajek ◽  
A. G. Veith
Keyword(s):  
Mechanical Properties ◽  
Shear Stress ◽  
Contact Zone ◽  
Flexural Rigidity ◽  
Comprehensive Evaluation ◽  
Shear Stiffness ◽  
Shear Stresses ◽  
Lateral Shear ◽  
Band Bending ◽  
Tread Rubber

Abstract Treadwear is explained by specific mechanical properties and actions of tires. Rubber shear stresses in the contact zone between the tire and the road become large at large slip angles. When normal stresses are insufficient to prevent sliding at the rear of the footprint, wear occurs at a rate that depends on test severity. Two experimental approaches are described to relate treadwear to tire characteristics. The first uses transducers imbedded in a simulated road surface to obtain direct measurements of contact stresses on the loaded, freely-rolling, steered tires. The second approach is developed with the aid of a simple carcass, tread-band, tread-rubber tire model. Various tire structural configurations; characterized by carcass spring rate, edgewise flexural band stiffness, and tread rubber shear stiffness; are simulated and lateral shear stress response in the contact zone is determined. Tires featuring high band stiffness and low carcass stiffness generate lower lateral shear stress levels. Furthermore, coupling of tread-rubber stiffness and band flexural rigidity are important in determining level of shear stresses. Laboratory measurements with the described apparatus produced values of tread-band bending and carcass lateral stiffness for several tire constructions. Good correlation is shown between treadwear and a broad range of tire stiffness and test course severities.

Stibnite vein from Dębowina near Bardo (polish Sudetes)

2013 ◽  
Vol 2 (1) ◽  
pp. 28-33
Author(s):  
Piotr Kotula
Keyword(s):  
Contact Zone

Abstract In the contact zone of the Bardo Structure and Kłodzko-Złoty Stok Intrusion and Kłodzko Metamorphic, metasomatic orebearing quartz-carbonate veins rich in Sb, Zn, Cu, Ag, Au, Pb are present. In 1771 the mine ,,Reiche Silber Gluck” within stibnite vein was founded in Dębowina near Bardo. Its entrance was discovered again in 2007. The stibnite vein is mainly build of stibnite and sphalerite and of quartz and dolomite rich in Mn. Stibnite crystallizes as columnar or forming radiate centres and aciculars. Its crystals reach size to 2 mm. Sphalerite appears as individual anhedral and polymineralic grained concentrations reaching size to 2,5 mm. Earlier pyrite and arsenopyrite crystallized - they occur locally in this deposit. There were found also in the deposit tetrahedrite rich in Ag, what wasn't reported earlier in studies from the mine in Dębowina.

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