The study reports major and trace element compositions of olivine in lamprophyre and related nephelinite dykes with well documented petrography and geochemistry from two areas in the Kola Alkaline ...Carbonatitic Province (KACP), Kandalaksha and Turij Mys. Variously zoned or homogeneous olivine (Fo82–88) occurs as phenocrysts, antecrysts and a groundmass phase in damtjernites, monchiquites and melanephelinites. Most olivine lies on two modelled Ni-Mg# trends formed via fractional crystallization for two distinct melt compositions, the higher Ni melt for Kandalaksha and the lower Ni, more evolved melt for Turij Mys. Contents of V and Sc in olivine indicate lower fO2 at QFM in the Kandalaksha melt and a 1 log unit higher fO2 in the Turij Mys melt. Trace element contents of olivine cannot constrain the mantle source for the parent melt because of its evolved, non-primary character indicated by low Mg# of the bulk rock(0.5–0.64) and olivine (0.81–0.87), and high Ca (1665–5325 ppm) and Mn (1193–2610 ppm) of the olivine. The study reaches this conclusion by comparing compositions of experimental mantle partial melts and their olivine with compositions of lamprophyres and lamprophyric olivine. Primary melts parental to KACP lamprophyres fractionated 24–26% of Fo89 before an ascent and crystallization of the lamprophyres in the lower crust. An analysis of global data for magmatic olivine in lamprophyres and kimberlites suggest the similarity of their initial primary melts followed by a diverging evolution. Trends of correlated Ni-Mg# in lamprophyres is controlled by olivine fractionation, unlike olivine kimberlite trends of the widely varying Ni at a constant Mg#. Globally, major and trace element chemistry of lamprophyre olivine resembles olivine from alkaline ultramafic massifs with carbonatites.
•Trace element compositions of olivine in ultramafic lamprophyres is controlled by fractional crystallization.•Primary melts parental to the studied KACP lamprophyres fractionated 24-26% Fo89•Olivine compositions of KACP lamprophyres indicate evolved character of the melts.•Identical initial primary melt compositions for kimberlites and lamprophyres•Lamprophyre melts are hypabyssal analogues of melts parental to alkaline ultramafic massifs with carbonatites
—Perovskite crystals from the ore-bearing olivinite and phoscorite of the Kugda massif were analyzed by LA-ICP-MS. Age obtained for the alkaline rocks of the Kugda massif is 257 ± 6 Ma. This implies ...that the Kugda massif was formed simultaneously with the Siberian flood basalts and Guli Massif (250 ± 9 Ma), which is the largest and highly differentiated pluton in the Maymecha–Kotuy Province. The simultaneous formation of the melilite-bearing Kugda Complex, Siberian flood basalts, and Guli Massif suggests the possible genetic relation of these rocks.
In current clinical practice the diagnosis of amnestic-mild cognitive impairment (a-MCI) is made on the basis of a patient’s Mini-Mental State Examination (MMSE) and the Alzheimer’s Disease ...Assessment Scale-Cognitive Subscale (ADAS-Cog), which have a high degree of subjectivity and do not give a complete picture of the patient’s health status. We have evaluated the effectiveness of a diagnostic index based on the activity of blood plasma butyrylcholinesterase (BChE) to confirm or refute the a-MCI diagnosis. The study involved 69 people: 36 patients diagnosed with a-MCI and 33 healthy volunteers. The a-MCI was diagnosed when the scores were less than 28 points on the MMSE and more than 2 points on the ADAS-Cog scales. Collection of blood and plasma separation from patients of both groups has been performed in a hospital setting. The activity of BChE forms was analysed by Ellman’s method combined with inhibitor analysis. The data on the activity of the atypical and minor forms of BChE were used to calculate an index correlating with the a-MCI diagnosis. Diagnostic intervals characteristic of patients with a-MCI and healthy volunteers have been determined. Comparison of the distribution of indicators of the calculated index by diagnosis categories was carried out using the χ-square test with Yates’ correction of the SPSS 22 (Statistical Package for the Social Sciences) software. The results of the study showed that diagnostics based on the ratio index of the activities of atypical and minor isoforms of BChE is not inferior to the standard diagnostic scales in terms of the sensitivity and specificity, and at the same time is a promising, minimally invasive, fast and cost-effective method for laboratory confirmation of the a-MCI diagnosis. The calculated diagnostic index proposed in this article is based on laboratory studies of the activity of atypical and minor isoforms of BChE in the blood plasma of patients with a preliminary diagnosis of a-MCI, which for the first time makes it possible to confirm the diagnosis by a laboratory method, avoiding subjectivity.
T cell costimulation by B7 molecules plays an important role in the regulation of alloimmune responses. Although both B7-1 and B7-2 bind CD28 and CTLA-4 on T cells, the role of B7-1 and B7-2 ...signaling through CTLA-4 in regulating alloimmune responses is incompletely understood. To address this question, we transplanted CD28-deficient mice with fully allogeneic vascularized cardiac allografts and studied the effect of selective blockade of B7-1 or B7-2. These mice reject their grafts by a mechanism that involves both CD4(+) and CD8(+) T cells. Blockade of CTLA-4 or B7-1 significantly accelerated graft rejection. In contrast, B7-2 blockade significantly prolonged allograft survival and, unexpectedly, reversed the acceleration of graft rejection caused by CTLA-4 blockade. Furthermore, B7-2 blockade prolonged graft survival in recipients that were both CD28 and CTLA-4 deficient. Our data indicate that B7-1 is the dominant ligand for CTLA-4-mediated down-regulation of alloimmune responses in vivo and suggest that B7-2 has an additional receptor other than CD28 and CTLA-4 to provide a positive costimulatory signal for T cells.
We studied the regularities of distribution of siderophile elements, including platinum group elements (PGE), in rock and in sulfides from Archean (2814 ± 51 Ma) peridotites collected in a fragment ...of deformed dike within the Bug granulite complex, Ukrainian Shield. In comparison with the primitive mantle, the studied rocks are enriched in Rh, Pd, Ni, Fe, and Co, and are characterized by low concentrations of other PGE. Sulfides are represented by a high-temperature variety of pentlandite and a small amount of chalcopyrite, with an inhomogeneous PGE distribution in them. Pd/Ir ratio typical of superchondrite is revealed for rocks and some sulfides. It is supposed that enrichment in Pd was not resulted from fractionation, but was rather related to mantle metasomatism. Saturation of the melt with sulfides and liquation process were favored by contamination of harzburgite with the host gneissic enderbite and fractionation of olivine. Solid sulfide solutions formed from sulfide melts at temperatures close to the crystallization temperature of magnesium phlogopite from a silicate melt.
The follicle-associated epithelium (FAE) of Peyer's patches (PPs) transports antigens and microorganisms into mucosal lymphoid tissues where they are captured by subepithelial dendritic cells (DCs). ...Feeding of cholera toxin (CT) induced migration of subepithelial DCs to interfollicular T-cell areas within 24 h. This study investigated short-term effects of CT, Escherichia coli heat-labile toxin, and non-toxic derivatives on DC migration. CT or CTB injected into ligated intestinal loops induced significant increase in CD11c+ DCs within the FAE within 90 min. In mice fed CT intragastrically, DC numbers in the FAE increased by 1 h, were maximal by 2 h, declined between 8 and 12 h, and were reversed by 24 h. Feeding of native LT, recombinant CTB, dibutyryl cyclic AMP, and to a lesser extent mutated CT(E29H) or mutated LT(R192G) had the same effect. Thus, both A and B subunits of enterotoxins, presumably acting through distinct signaling pathways, may promote capture of incoming antigens and pathogens by PP DCs.
Currently, one of the most pressing concerns of labor psychology and healthcare is emotional burnout in healthcare professionals. During the COVID- 19 pandemic this condition has become very ...significant due to it takes a lot of physical, phychoemotional and ethical commitment of medical personnel. Emotional burnout is a syndrome that derives from chronic stress and leads to the depletion of personal, emotional, and energy resources of a person in the professional life. It is an dynamic sequential process and relevant to stress stages (the alarm stage, the resistance stage and the exhaustion stage). There are many various factors inducing the burnout syndrome: social, political, economic, bureaucratic, etc. In the process of studying this phenomenon, different models of emotional burnout were proposed. The most famous model is the three-part model of burnout by С. Maslach, which includes emotional exhaustion, depersonalization and a decrease in personal achievements. In Russia V. V. Boyko has been studying the burout phenomenon. There are three main stages of emotional burnout (alarm, resistance and exhaustion), which have a close connection to stress stages; each stage has a specific combination of symptoms. According to a number of authors, burnout syndrome is closely related to empathy, therefore, it is necessary to study the relationship between the level of empathy and the degree of emotional burnout in healthcare professionals for planning further psychological support for the prevention of this syndrome.
Perovskite crystals from ore-bearing olivinite and phoscorite of Kugda Massif were analyzed by LA-ICP-MS. Age obtained for alkaline rocks of Kugda Massif is 2576 Ma. It means that Kugda massif was ...formed simultaneously with the Siberian flood basalts and Guli Massif (2509 Ma) which is the largest pluton in the Maymecha-Kotuy Province and is highly differentiated. The melilite-bearing Kugda Complex was formed synchronously with Siberian Trapps and Guli Massif, which suggests that these rocks might be genetically related.
The phenomenon of tolerance to noninherited maternal Ags (NIMA) is poorly understood. To analyze the NIMA effect C57BL/6 (H-2(b/b)) males were mated with B6D2F(1) (H-2(b/d)) females, whereby 50% of ...the offspring are H-2(b/b) mice that have been exposed to maternal H-2(d) alloantigens. Controls were H-2(b/b) offspring of C57BL/6 mothers, either inbred C57BL/6 mice or F(1) backcross mice from breedings with H-2(b/d) fathers. We found that 57% of the H-2(b/b) offspring of semiallogeneic (H-2(b/d)) mothers accepted fully allogeneic DBA/2 (H-2(d/d)) heart grafts for >180 days, while similar transplants were all rejected by day 11 in controls (p < 0.0004). Foster nursing studies showed that both oral and in utero exposure to NIMA are required for this tolerogenic effect. An effect of NIMA was also found to extend the survival of skin grafts from a semiallogeneic donor (p < 0.02). Pretransplant analysis of splenocytes showed a 40-90% reduction of IL-2-, IL-5-, and IFN-gamma-producing T cells responding to H-2(d)-expressing APC in NIMA(d)-exposed vs control mice. Injection of pregnant BALB/c-dm2 (H-2L(d)-negative) female mice i.v. with H-2L(d)(61-80) peptide profoundly suppressed the offspring's indirect pathway alloreactive CD4(+) T cell response to H-2L(d). These results suggest that the natural exposure of the fetus and newborn to maternal cells and/or soluble MHC Ags suppresses NIMA-allospecific T cells of the offspring, predisposing to organ transplant tolerance in adult mice.
Geological, tectonic, and mineralogical peculiarities of the deposit. The FedorovoPanskii massif is located in the central part of the Kola Peninsula and from the geomorphological point of view is ...represented by an elongated (>80 km) and narrow (36 km) mountain ridge of northwestern orientation. The intrusion occurs in the zone of the northern contact between volcanogenicsedimentary rocks of the Imandra Varzugskaya Paleoproterozoic paleoriftogenic struc ture represented by greenstone formations of the Rizhgubskaya and Seidorechevskaya Suites and for mations of the Precambrian basement represented by young alkaline granite and ancient (Mesoarchean) plagiogneissgranite.
PDF
