The composition of amphibole phenocrysts in Neogene mafic volcanic rocks from the Puna plateau: Insights on the evolution of hydrous back-arc magmas

In typical Andean arc magmas, amphibole appears as a phenocryst phase only after considerable differentiation. However, some near-primitive volcanic rocks (high-Mg andesites and basalts) from monogenetic centers in the Puna plateau of Argentina also contain amphibole phenocrysts, implying special conditions of hydrous magma generation in this back-arc setting. This study documents typical examples from Southern and Northern Puna regions and uses the major and trace-element compositions of amphibole to constrain a petrogenetic model for the hydrous magmas. There are significant differences in the nature of amphiboles and their host lavas depending on location of the volcanic centers in the Southern and the Northern Puna regions. In the Southern Puna, basaltic andesitic lavas have Sr/Y values >40 and amphiboles show skeletal forms and occur in an assemblage with olivine and pyroxene. The amphibole compositions are relatively Al- and Ti-poor compared to the Northern Puna. Thermobarometry indicates amphibole crystallization temperatures of 960–1000 °C at moderate pressure (1000 °C) and pressures (6–8 kbar). Furthermore, the chemical composition of amphibole phenocrysts in the Northern Puna Campo Negro center suggests an alkaline affinity of the parental magmas which, together with radiogenic isotope data from earlier studies, indicates a significant contribution of the enriched lithosphere in the magma source. The new data collectively suggest high pressure evolution of hydrous magmas in the Southern Puna, whereas the Northern Puna magmas underwent more differentiation at higher levels in the crust. This contrast in the evolution history of magmas below both regions can be connected with their position relative to partial melting zones in the mid-upper crust, which are larger and longer-lived in the north than in the south, thus favoring a slower ascent of magmas in that region.Fil: Maro, Guadalupe. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Trumbull, Robert. German Research Centre for Geosciences; AlemaniaFil: Caffe, Pablo Jorge. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jofré, Cynthia Betina. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Filipovich, Ruben Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Frick, Daniel A.. German Research Centre for Geosciences; Alemani

Natural killer cell dysfunction is a distinguishing feature of systemic onset juvenile rheumatoid arthritis and macrophage activation syndrome

Macrophage activation syndrome (MAS) has been reported in association with many rheumatic diseases, most commonly in systemic juvenile rheumatoid arthritis (sJRA). Clinically, MAS is similar to hemophagocytic lymphohistiocytosis (HLH), a genetic disorder with absent or depressed natural killer (NK) function. We have previously reported that, as in HLH, patients with MAS have profoundly decreased NK activity, suggesting that this abnormality might be relevant to the pathogenesis of the syndrome. Here we examined the extent of NK dysfunction across the spectrum of diseases that comprise juvenile rheumatoid arthritis (JRA). Peripheral blood mononuclear cells (PBMC) were collected from patients with pauciarticular (n = 4), polyarticular (n = 16), and systemic (n = 20) forms of JRA. NK cytolytic activity was measured after co-incubation of PBMC with the NK-sensitive K562 cell line. NK cells (CD56(+)/T cell receptor [TCR]-αβ(-)), NK T cells (CD56(+)/TCR-αβ(+)), and CD8(+ )T cells were also assessed for perforin and granzyme B expression by flow cytometry. Overall, NK cytolytic activity was significantly lower in patients with sJRA than in other JRA patients and controls. In a subgroup of patients with predominantly sJRA, NK cell activity was profoundly decreased: in 10 of 20 patients with sJRA and in only 1 of 20 patients with other JRA, levels of NK activity were below two standard deviations of pediatric controls (P = 0.002). Some decrease in perforin expression in NK cells and cytotoxic T lymphocytes was seen in patients within each of the JRA groups with no statistically significant differences. There was a profound decrease in the proportion of circulating CD56(bright )NK cells in three sJRA patients, a pattern similar to that previously observed in MAS and HLH. In conclusion, a subgroup of patients with JRA who have not yet had an episode of MAS showed decreased NK function and an absence of circulating CD56(bright )population, similar to the abnormalities observed in patients with MAS and HLH. This phenomenon was particularly common in the systemic form of JRA, a clinical entity strongly associated with MAS

МЕТОДИКА СИНТЕЗА КВАЗИДВУХПОЛОСОВЫХ СОГЛАСУЮЩИХ УСТРОЙСТВ

The article presents some findings on the potential of analytical methods for the synthesis of broadband matching circuits for solving nontrivial circuit engeneering problems. Nontriviality shows itself in the technique for the assignment of the frequency response model (approximation) for the broadband synthesis in cellular communication, when double-band antennas are essential. The frequency response model appears as the result of frequency transformation, which yields in the assignment of both bands at the very first stage of the synthesis. The bands’width and isolation between them may be controlled independently, which is the essential part of the frequency transformation. Such way offrequency response assignment allows the potential of the method, which is always restricted by a load, to find broader application. In these conditions the frequency response turns to a quasi-double and asymmetrical one due to finite isolation between bands. We also present the general approach to the synthesis, which incorporates both the frequency transformation and novel synthesis technique. The modified frequency transformation can be applied to all types oftraditional approximations of arbitrary orders in synthesizing broadband frequency-selective matching devices. The distinctive feature of this technique is in the use of generalized Darlington’s synthesis for solving the problems of broadband matching of resistances in a lumped element basis with the application of frequency reponses obtained through modified frequency transformation. We have also estimated the efficiency of the developed technique by comparison with the known results.В статье представлены результаты исследования потенциальных возможностей аналитических методов синтеза широкополосных согласующих устройств для решения некоторых нестандартных схемотехнических задач. Нестандартность проявляется в способе задания частотной характеристики при синтезе цепи согласования в таких системах, как сотовая связь, когда необходимо обеспечить работу антенны в двух диапазонах. Способ задания частотной характеристики заключается в использовании частотного преобразования, которое дает возможность на начальном этапе синтеза задавать полосы пропускания диапазонов. Существенными особенностями является возможность независимого управления полосами пропускания диапазонов в процессе синтеза и величиной их изоляции. Такой способ задания частотной характеристики позволяет в большей степени использовать потенциальные характеристики метода согласования, всегда ограниченные сопротивлением нагрузки. Частотная характеристика в этих условиях становится квазидвухполосовой и имеет асимметрию, обусловленную конечной изоляцией диапазонов. Выработана и представлена общая концепция подхода к синтезу, которая включает разработку как модифицированного частотного преобразования, так и новой методики синтеза согласующей цепи. Полученное в результате исследований модифицированное частотное преобразование можно применять для всех видов классических аппроксимирующих функций произвольного порядка, используемых в задачах синтеза широкополосных частотно-избирательных согласующих устройств. Особенность методики заключается в использовании обобщенного метода Дарлингтона для задач широкополосного согласования сопротивлений в сосредоточенном элементном базисе с применением частотных характеристик, полученных при помощи модифицированного преобразования частоты. Также произведена оценка эффективности разработанной методики путем сравнения с известными результатами

Согласование патч-антенны с кросс-поляризацией для геолокации

The article presents the study results of the possibilities of expanding the working frequency band of a patch antenna, due to the broadband matching. As a systematic approach, a generalized Darlington method is proposed using flexible approximating functions with increased variable properties. These properties are necessary for the solvability of the system of restrictions on the agreement limits. The results of synthesis by the generalized Darlington method using flexible approximations provide a matching band of 10 %, but have an increased sensitivity of the values of concentrated elements. A synthesis technique in a distributed element basis is also presented. In the synthesis of a matching chain on distributed elements, the Richards transform for homogeneous microstrip lines is used. A comparison of theoretical and experimental results of antenna matching is presented. Synthesis on distributed elements provided a 17 % band with a minimum number of matching elements. The synthesis technique in the distributed element basis can be used to match a wide class of vibrator and slot antennas, the dimensions of which are multiples of a wavelength quarter. В статье представлены результаты исследования возможностей расширения рабочей полосы частот патч-антенны за счет широкополосного согласования. В качестве системного подхода предлагается обобщенный метод Дарлингтона с использованием гибких аппроксимирующих функций, обладающих повышенными вариативными свойствами. Эти свойства необходимы для разрешимости системы ограничений на пределы согласования. Результаты синтеза по обобщенному методу Дарлингтона с применением гибких аппроксимаций обеспечивают полосу согласования 10 %, однако имеют повышенную чувствительность номиналов сосредоточенных элементов. Также представлена методика синтеза в распределенном элементном базисе. В синтезе согласующей цепи на распределенных элементах использовано преобразование Ричардса для однородных микрополосковых линий. Представлено сравнение теоретических и экспериментальных результатов согласования антенны. Синтез на распределенных элементах обеспечил полосу 17 % при минимальном количестве согласующих элементов. Методика синтеза в распределенном элементном базисе может использоваться для согласования широкого класса вибраторных и щелевых антенн, размеры которых кратны четверти длины волны.

Immunomagnetic t-lymphocyte depletion (ITLD) of rat bone marrow using OX-19 monoclonal antibody

Graft versus host disease (GVHD) may be abrogated and host survival prolonged by in vitro depletion of T lymphocytes from bone marrow (BM) prior to allotransplantation. Using a mouse anti-rat pan T-lymphocyte monoclonal antibody (0×19) bound to monosized, magnetic, polymer beads, T lymphocytes were removed in vitro from normal bone marrow. The removal of the T lymphocytes was confirmed by flow cytometry. Injection of the T-lymphocyte-depleted bone marrow into fully allogeneic rats prevents the induction of GVHD and prolongs host survival. A highly efficient technique of T-lymphocyte depletion using rat bone marrow is described. It involves the binding of OX-19, a MoAb directed against all rat thy-mocytes and mature peripheral T lymphocytes, to monosized, magnetic polymer spheres. Magnetic separation of T lymphocytes after mixing the allogeneic bone marrow with the bead/OX-19 complex provides for a simple, rapid depletion of T lymphocytes from the bone marrow. In vitro studies using flow cytometry and the prevention of GVHD in a fully allogeneic rat bone marrow model have been used to demonstrate the effectiveness of the depletion procedure. © 1989 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted