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221.
Subspecific relationships of the European beaverCastor fiber have been obscured by failure to follow the rules of the International Code of Zoological Nomenclature and remain an open
issue. Inconsequence in the use of subspecies names caused a nomenclatural as well as a taxonomic confusion. We discuss these
controversial and incorrect nomenclatural decisions, and recognize 9 nominal subspecies of European beaver, bearing 9 available
names:C. f. fiber Linnaeus, 1758,C. f. galliae Geoffroy, 1803, C. f. albicus Matschie, 1907,C. f. vistulanus Matschie, 1907,C. f. pohlei Serebrennikov, 1929,C. f. birulai Serebrennikov, 1929,C. f. tuvinicus Lavrov, 1969,C. f. belorussicus Lavrov, 1981, andC. f. orientoeuropaeus Lavrov, 1981. 相似文献
222.
223.
1. Bovine erythrocytes exposed to the action of an enzymic source of hyperoxide radicals (hypoxanthine + xanthine oxidase) exhibited hemolysis, which was prevented by the presence of hyperoxide dismutase. 2. Exposing bovine erythrocyte membranes to the source of hyperoxide radicals resulted in a decrease of (Mg2+ + Na+ + K+)ATPase activity which could be partially prevented by addition of hyperoxide dismutase. 3. The damage observed to erythrocyte membranes under the conditions applied is ascribed to toh formed in the Haber and Weiss reaction since a protection by OH scavengers was also observed. 相似文献
224.
Origins of Life and Evolution of Biospheres - Lethal radiation, low vacuum pressure and low temperatures – this is how space welcomes organisms. Crossing of immense interstellar distances... 相似文献
225.
226.
Hemoglobin can nitrate itself and other proteins. 总被引:4,自引:0,他引:4
Incubation of human hemoglobin with nitrite and hydrogen peroxide was found to induce autonitration and nitration of another protein (bovine serum albumin), as demonstrated by detection of nitrotyrosine residues in Western blots of separated membrane proteins. Inhibition of nitration by conversion of hemoglobin into the cyanmet form demonstrates that nitration is due to the pseudoperoxidase activity of hemoglobin. Incubation of whole erythrocytes with nitrite and hydrogen peroxide induces nitration of erythrocyte membrane proteins, much stronger when cellular catalase was inhibited with azide. These results suggest that hemoglobin and other hemoproteins may contribute to the tyrosine nitration in vivo. 相似文献
227.
The geometric and energetic characteristics of root surfaces of two wheat (Triticum L.) varieties, Al tolerant (Inia 66/16) and Al sensitive (Henika), were estimated from experimental water vapor adsorption–desorption data. Roots stressed for around 1 week at pH 4 without and with a toxic aluminium level (0.741 mol m–3) were studied at the tillering and shooting stages. Roots grown continuously at pH 7 were taken as control. The surface properties of the pH 4 stressed roots were apparently the same as those of the control roots whatever the root age. For the roots of both varieties, the surface area and total micropore volume increased markedly after aluminium treatment. The average micropore radius increased significantly for the sensitive wheat, whereas it increased only slightly for the resistant one. Under Al treatment the number of large pores increased while small pores were fewer for both plants, indicating a possible alteration of the build-up of root tissue. The root surface pores were fractal. The fractal dimension of the sensitive wheat roots decreased under Al treatment, whereas for the resistant wheat this remained apparently unchanged. The adsorption energy distribution functions had different shapes for the sensitive and the resistant wheat varieties: the sensitive variety had greater number of high energy adsorption centers, which implies that the root tolerance on Al stress may be connected with lower polarity of the surface. 相似文献
228.
229.
Artur Klepaczko Piotr Szczypiński Grzegorz Dwojakowski Micha? Strzelecki Andrzej Materka 《PloS one》2014,9(4)
With the development of medical imaging modalities and image processing algorithms, there arises a need for methods of their comprehensive quantitative evaluation. In particular, this concerns the algorithms for vessel tracking and segmentation in magnetic resonance angiography images. The problem can be approached by using synthetic images, where true geometry of vessels is known. This paper presents a framework for computer modeling of MRA imaging and the results of its validation. A new model incorporates blood flow simulation within MR signal computation kernel. The proposed solution is unique, especially with respect to the interface between flow and image formation processes. Furthermore it utilizes the concept of particle tracing. The particles reflect the flow of fluid they are immersed in and they are assigned magnetization vectors with temporal evolution controlled by MR physics. Such an approach ensures flexibility as the designed simulator is able to reconstruct flow profiles of any type. The proposed model is validated in a series of experiments with physical and digital flow phantoms. The synthesized 3D images contain various features (including artifacts) characteristic for the time-of-flight protocol and exhibit remarkable correlation with the data acquired in a real MR scanner. The obtained results support the primary goal of the conducted research, i.e. establishing a reference technique for a quantified validation of MR angiography image processing algorithms. 相似文献
230.
Lidia Poplawska-Szczyglowska Jan Walewski Barbara Pienkowska-Grela Grzegorz Rymkiewicz Olga Mioduszewska 《Cancer immunology, immunotherapy : CII》1999,16(1):65-68
A 68-year-old man presented with hemiparesis, lymphocytosis, and cerebral lesions on MRI. Flow cytometry of blood, bone marrow
and cerebrospinal fluid showed B-CLL lymphocytes with bright CD20 expression, slg, and absence of CD23 antigen. Fluorescencein situ hybridisation showed trisomy 12 in 50% of analysed peripheral mononuclear cells. The patient died 6 months after the diagnosis.
Rapidly progressive and fatal course of the disease was consistent with known bad prognostic significance of CD20 bright expression
and trisomy 12. 相似文献