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971.
972.
Benjamin Proshek Lindsay A. Crawford Corey S. Davis Sylvie Desjardins Allison E. Henderson Felix A. H. Sperling 《Journal of Insect Conservation》2013,17(1):155-170
Like many species, the Mormon Metalmark butterfly (Apodemia mormo) has been given conservation ranking in Canada based on limited data. This species is widespread across western North America, but has only two populations in Canada: an “endangered” population in the Similkameen valley of British Columbia, and a “threatened” population in Grasslands National Park (GNP) in Saskatchewan. Here we present genetic data from 1498 base pairs of the cytochrome oxidase I gene sequence and six novel microsatellite loci in order to assess (1) whether the two populations are related, (2) the degree to which they are genetically diverse and demographically stable, and (3) what their relationships are to the nearest unranked populations of A. mormo across the Canada-United States border. Our principal conclusion is that the two populations are not closely related genetically. We also found that the British Columbia population is genetically depauperate and, with the exception of the nearest neighboring populations across the border, not recently genetically connected to other populations in the Pacific Northwest. In comparison, the Saskatchewan population is genetically diverse, and gene flow occurs with several other eastern populations. Population structure was not detected within either the British Columbia or the Saskatchewan populations. This research supports the prior conservation rankings of both populations and provides new insight that will help to inform future management decisions for the Canadian populations of this charismatic butterfly. 相似文献
973.
974.
975.
A closed set of reduced equations describing low-frequency nonlinear flute magnetohydrodynamic (MHD) convection and the resulting nondiffusive processes of particle and energy transport in a weakly collisional cylindrical plasma with an anisotropic pressure is derived. The Chew-Goldberger-Low anisotropic magnetohydrodynamics is used as the basic dynamic model, because this model is applicable to describing flute convection in a cylindrical plasma column even in the low-frequency limit. The reduced set of equations was derived using the method of adiabatic separation of fast and slow motions. It is shown that the structure of the adiabatic transformation and the corresponding velocity field are identical to those obtained earlier in the isotropic MHD model. However, the derived heat transfer equations differ drastically from the isotropic pressure model. In particular, they indicate a tendency toward maintaining different radial profiles of the longitudinal and transverse pressures. 相似文献
976.
Electrical discharges that burn inside an electrolyte bulk and have challenging practical applications are presented. The data on electrophysical and spectral properties of an underwater end-face discharge allowed suggesting the scenario of the discharge origination and development. It includes three stages: bubble growth, a quiet discharge, and an active discharge stage. 相似文献
977.
The reflection of a test electromagnetic pulse from the plasma formed as a result of tunnel ionization of atoms in the field of a circularly polarized high-power radiation pulse is analyzed using the kinetic approach to describe electron motion. It is shown that the reflected pulse is significantly amplified due to the development of Weibel instability. The amplification efficiency is determined by the maximum value of the instability growth rate, which depends on the degree of anisotropy of the photoelectron distribution function. 相似文献
978.
I. V. Sorokina D. S. Baev N. A. Zhukova T. G. Tolstikova A. N. Antimonova N. I. Petrenko E. E. Shults I. A. Grigor’ev 《Russian Journal of Bioorganic Chemistry》2013,39(6):668-670
Betulonic acid amides containing the nitroxyl radical moiety exert an anticholestatic effect in mice. The introduction of piperidine nitroxide moiety into the lupane core increases its hepatoprotective activity. Oral administration of the piperidine nitroxide derivative in a dose of 50 mg/kg does not stimulate transplanted tumor growth and increases lifespan in mice. 相似文献
979.
N. R. Kuznetsova E. V. Svirshchevskaya N. S. Sitnikov L. Abodo H. Sutorius J. Zapke J. Velder P. Thomopoulou H. Oschkinat A. Prokop H. -G. Schmalz A. Yu. Fedorov E. L. Vodovozova 《Russian Journal of Bioorganic Chemistry》2013,39(5):543-552
Colchicine site binders—blockers of tubulin polymerization—are potential antimitotic agents for anticancer therapy. To reduce their systemic toxicity and improve biodistribution, encapsulation in nanosized liposomes may be employed. Liposomes present a convenient means for preparation of injectable for-mulations of hydrophobic compounds, however colchicine as such is known to leak through the lipid bilayer. In this study, newly synthesized triazole-containing analogues of colchicine and allocolchicine, and their palmitic and oleic esters (lipophilic prodrugs) were tested for anti-proliferative activity and apoptosis-inducing potential. In contrast to colchicine conjugates, whose activities ranged with those of colchicine, allocolchicine derivatives exhibited drastically lower effects and were discarded. Liposomes of about 100 nm in diameter composed of egg phosphatidylcholine-yeast phosphatidylinositol-palmitic or oleic prodrug, 8: 1: 1, by mol, were prepared by standard extrusion technique and tested in a panel of four human tumor cell lines. Liposome formulations preserved the biological activities of the parent colchicinoid the most towards human epithelial tumor cells. Moreover, liposomal form of the oleoyl bearing colchicinoid inhibited cell proliferation more efficiently than free lipophilic prodrug. Due to substantial loading capacity of the liposomes, the dispersions contain sufficient concentration of the active agent to test wide dose range in experiments on systemic administration to animals. 相似文献
980.
We found a new non-native haplotype of Phragmites australis in North America that provides convincing evidence for multiple introductions of this highly invasive reed from Europe. Prior to our detection of this new non-native haplotype, invasion of North America by this reed grass was thought to be limited to a single cp-DNA haplotype–haplotype M. However, we found two sites colonized by haplotype L1 in Quebec, Canada, a haplotype native to northern Europe, Great Britain and Romania. Because the invasion of North America by P. australis is ongoing, and because there is evidence for intra- and inter-specific hybridization and increased fecundity resulting from outcrossing, more attention should be paid to genetic differences and associated vigor of populations of introduced Phragmites across North America. 相似文献