The origin of iron oxide-apatite deposits is controversial. Silicate liquid immiscibility and separation of an iron-rich melt has been invoked, but Fe-Ca-P-rich and Si-poor melts similar in composition to the ore have never been observed in natural or synthetic magmatic systems. Here we report experiments on intermediate magmas that develop liquid immiscibility at 100 MPa, 1000-1040 °C, and oxygen fugacity conditions (fO) of ∆FMQ = 0.
View Article and Find Full Text PDFA majority of MRI procedures requiring intravascular injections of contrast agents are performed with paramagnetic chelates. Such products induce vascular signal enhancement and they are rapidly excreted by the kidneys. Unfortunately, each chelate is made of only one paramagnetic ion, which, taken individually, has a limited impact on the MRI signal.
View Article and Find Full Text PDFThree-way junctions in folded RNAs have been investigated both experimentally and computationally. The interest in their analysis stems from the fact that they have significantly been found to possess a functional role. In recent work, three-way junctions have been categorized into families depending on the relative lengths of the segments linking the three helices.
View Article and Find Full Text PDFThe highest content of hydroxyproline, hexuronic acids and hexoses was found in nonmetastatic tumor tissue Ca 755 of mice as compared with metastatic neoplasms carcinoma 3LL and melanoma B-16. Development of melanoma B-16 metastases involved the active lung stromal reaction, while carcinoma 3LL metastatic spreading did not cause any distinct connective tissue reactions in lungs. Non-toxic doses of drugs, operating via dissimilar mechanisms (cyclophosphane, trielin, parmidine), resulted in similar alterations of the connective tissue components studied in primary tumors of both carcinoma 3LL and melanoma B-16.
View Article and Find Full Text PDFThe fibrinolysis system components of the circulating blood plasma have been studied in experiments on C57Bl/6 mice in the dynamics of growth and metastasis of the Lewis lung carcinoma. It has been shown that a growth and metastasis of malignant tumours are accompanied by the fibrinolysis activity inhibition. Changes in the fibrinolysis processes are observed already on the 3rd day after tumour inoculation.
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