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排序方式: 共有450条查询结果,搜索用时 31 毫秒
441.
442.
Serge Utevsky Nataliya Kovalenko Karyna Doroshenko Laima Petrauskienė Vyacheslav Klymenko 《Systematic parasitology》2009,74(2):95-102
Karyological preparations were made from the testisacs of three medicinal leech species Hirudo medicinalis Linnaeus, 1758, H. verbana Carena, 1820 and H. orientalis Utevsky & Trontelj, 2005
. The samples originated from different populations in Azerbaijan, Kazakhstan, Russian Federation, Ukraine and Uzbekistan.
The chromosome numbers were determined both from mitotic and meiotic stages of spermatogenesis using the propionic haematoxylin
staining technique. All three species were found to have different haploid chromosome numbers: H. medicinalis 14, H. verbana 13 and H. orientalis 12, thus corroborating the validity of these taxa. The chromosomes can be classified as meta-, submetacentric and acrocentric.
The chromosome numbers obtained are similar to that of the related species Haemopis sanguisuga (Linnaeus, 1758), which has 13 pairs. 相似文献
443.
444.
Nataliya R. Rovnyagina Gleb S. Budylin Pavel V. Dyakonov Yuri M. Efremov Marina M. Lipina Yuliya R. Goncharuk Emirkhan E. Murdalov David A. Pogosyan Denis A. Davydov Alexander A. Korneev Natalia B. Serejnikova Karen A. Mikaelyan Stanislav A. Evlashin Vladimir A. Lazarev Alexey V. Lychagin Peter S. Timashev Evgeny A. Shirshin 《Journal of biophotonics》2023,16(3):e202200149
Osteoarthritis (OA) is one of the most common joint diseases worldwide. Unfortunately, clinical methods lack the ability to detect OA in the early stages. Timely detection of the knee joint degradation at the level of tissue changes can prevent its progressive damage. Here, diffuse reflectance spectroscopy (DRS) in the NIR range was used to obtain optical markers of the cartilage damage grades and to assess its mechanical properties. It was observed that the water content obtained by DRS strongly correlates with the cartilage thickness (R = .82) and viscoelastic relaxation time (R = .7). Moreover, the spectral parameters, including water content (OH-band), protein content (CH-band), and scattering parameters allowed for discrimination between the cartilage damage grades (10−4 < P ≤ 10−3). The developed approach may become a valuable addition to arthroscopy, helping to identify lesions at the microscopic level in the early stages of OA and complement the surgical analysis. 相似文献
445.
446.
Elevated congenital anomaly rates and incorporated cesium‐137 in the Polissia region of Ukraine
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447.
448.
The increasing concentrations of ambient ozone observed during recent decades in many industrial and rural regions of the world present hazard for vegetation and human health. The problem of protection of sensitive vegetation from ozone damage could be ameliorated by replacement of sensitive biotypes with more tolerant ones as well as by application of chemical protectants. However, application of synthetic protectants will pollute the environment and agricultural production and may also have dose-dependent toxicity to vegetation. Therefore, it is urgent to develop alternative, environmentally antiozonants, for example, compounds based on natural plant antioxidants. In this article the literature has been reviewed in search of works relating to the potential of natural plant antioxidants that might serve to protect sensitive vegetation from ozone damage. The following groups of antioxidants have been discussed: (i) ascorbic acid and its derivatives, (ii) phytohormones, (iii) flavonoids, and (iv) polyamines. The physiological aspects of their protective effect on ozone-sensitive crops have been considered. Possible phytotoxicity resulting from their application in the field has been discussed. The issues needing further studies have been outlined. 相似文献
449.
S. A. Goncharuk A. A. Shulga Ya. S. Ermolyuk P. K. Kuzmichev V. A. Sobol E. V. Bocharov V. V. Chupin A. S. Arseniev M. P. Kirpichnikov 《Biochemistry. Biokhimii?a》2009,74(12):1344-1349
An efficient method is described for production of membrane protein KCNE3 and its isotope labeled derivatives (15N-, 15N-/13C-) in amounts sufficient for structural-functional investigations. The purified protein preparation within different detergent
micelles was characterized using dynamic light scattering, CD spectroscopy, and NMR spectroscopy. It is shown that within
DPC/LDAO micelles the protein is in monomeric form and acquires mainly α-helical conformation. The existence of cross-peaks
for all glycines of the 15N-HSQC NMR spectra as well as relatively small line widths (∼20 Hz) confirm the high quality of the preparation and the possibility
of obtaining structural-dynamic information on KCNE3 by high resolution heteronuclear NMR spectroscopy. 相似文献
450.
Luciana G. Naso Evelina G. Ferrer Nataliya Butenko Isabel Cavaco Luis Lezama Teófilo Rojo Susana B. Etcheverry Patricia A. M. Williams 《Journal of biological inorganic chemistry》2011,16(4):653-668
A new complex of the oxovanadium(IV) cation with the flavolignan silibinin has been synthesized and characterized. Vanadium
compounds show interesting biological and pharmacological properties and some of them display antitumoral actions. Flavonoids
are part of a larger group of antioxidant compounds called polyphenols which may inhibit the proliferation and growth of cancer
cells. The antioxidant and antitumoral effects of silibinin and its oxovanadium(IV) complex were investigated. Silibinin acted
as a very strong antioxidant and its complexation with oxovanadium(IV) improved this behavior. Besides, the generation of
reactive oxygen species (ROS) by this compound was favored in tumoral (UMR106) cells and correlated with the deleterious behavior
in the proliferation of this cell line. Conversely, silibinin did not exert any effect on the proliferation of normal osteoblasts
(MC3T3E1). The cytotoxic action and ROS generation of the oxovanadium(IV) complex was more effective in tumoral cells. This
behavior was not consistent with cleaving DNA of plasmid DNA pA1 because no significant cleaving activity was observed in
both cases. These results suggest that the main deleterious mechanisms may take place through cytotoxic effects more than
genotoxic actions. A comparison with our own findings on the behavior of other flavonoids and their vanadyl(IV) complex has
also been performed. 相似文献