СФЕРИЧЕСКИЕ МИКРОЧАСТИЦЫ ИЗ ЗОЛОТОРУДНЫХ КВАРЦЕВЫХ ЖИЛ ИРОКИНДИНСКОГО МЕСТОРОЖДЕНИЯ (ЗАПАДНОЕ ЗАБАЙКАЛЬЕ)

We have studied the material composition of ore microparticles extracted from gold concentrates of operating quartz vein No. 30 located in the Irokinda deposit, Western Transbaikalia. We consider the origin of such microparticles in connection with our observation data and the previously published structural and geological features revealed in formation of the ore field, as well as tectonophysical conditions of formation of many gold-bearing quartz veins, including vein No. 30.Gold-quartz veins, located in the allochthonous plate thrusted onto the Kelyano-Irokinda belt (Fig. 1), infill the NE-striking fault zones. E.A. Namolov conducted the tectonophysical analysis of the “elementary fracture – ore-bearing suture/joint” system, which provided a genetic explanation of the morphology of ore quartz veins (including vein No. 30) and conditions for formation of their host fault zones. Ore-bearing fractures are combinations of shear and cleavage cracks that occur in case of certain positions of the strain ellipsoid in conditions of horizontal compression. Due to repeated intra-mineralization displacements, the texture of the ores is strappy, and the quartz matrix of the veins contains numerous inclusions of host rocks.The spherical particles have zonal structures and consist of metal nodes and external continuous or discontinuous shells, which thickness ranges from 10 to 400 microns (Fig. 2, Fig. 3). The nodes are composed mainly of native Fe with admixtures of Fe, Mn, Al (Table), the contents of which are typically less than 1.0–1.5 wt %.Characteristic features of the mineral composition of shells of the spheroidal microparticles:– The widespread graphite matrix consisting of minerals of different classes, except for native;– Pyrite in the group of ore oxides of Fe, Mn, Cr, Ti;– A large group of carbonate minerals;– Feldspars and natrosilite among silicates;– The mineral with CaBr2 composition;– Mono-mineral quartz rims.The consequence of metamorphism, i.e. deformational or mechano-chemical transformations of rocks in Irokinda, as well as the autochthon (the rock bed of the Kelyano-Irokinda belt), is the gas-water (‘hydrothermal’) system capable of forming the spherical ore particles with low-temperature mineral rims.The main feature of the structure of the spherical microparticles in Irokinda is a sharp contrast of the crystallization conditions of the metal nodes and their rims. Similar conditions leading to formation of contrasting mineral associations, that are similar in compositions to the discussed spherules, are characteristic of the gas-water-lithoclastitic and gas-water stages of mud volcanoes. For these stages, we suggest the cavitation mechanism of formation of spherical metal particles of Fe, Fe–Cr and other compositions, which is accompanied by combustion (pyrogenic melt) and pyrolysis of hydrocarbon components of the fluid. This mechanism, with the exception of the origin of the melt (in this case, of the friction type) seems to most closely correspond to the actual data.  The spheroids are likely to have formed in the pre-ore stage of formation of the quartz veins.The high-temperature metal spherical microparticles revealed in our study can be regarded as specific indicators showing conditions in which the ore-forming system of the dynamo-metamorphic type was functioning to produce gold mineralization on the Irokinda deposit. The structure and composition of these microparticles differ from those of the microspherules from other gold deposits in Transbaikalia (black shale formation in Sukhoi Log, and low–sulphide gold–quartz ore formation in Pervenets), which also belong to the dynamogenic genetic type. However, the ore-forming systems of the compared deposits have two common factors that contribute to formation of spherical microparticles – high tectonic activity manifested by repeated (impulse-type) tectonic movements, and the associated unstable pressure conditions. The consequence of the latter is heterogenization of the gas-water fluid, which, in turn, leads to the cavitation and froth flotation mechanisms.Приведены результаты изучения вещественного состава рудных микрочастиц, извлеченных из золотосодержащих концентратов эксплуатируемой кварцевой жилы № 30 Ирокиндинского месторождения. Авторы попытались рассмотреть их происхождение в связи с опубликованными ранее результатами исследований структурно-геологических особенностей формирования рудного поля, а также тектонофизических условий образования многих золоторудных кварцевых жил, включая и жилу № 30, дополненных нашими наблюдениями.Золоторудные кварцевые жилы локализованы в аллохтонной пластине (рис. 1), надвинутой на Келяно-Ирокиндинский пояс. Они выполняют зоны разломов северо-восточного простирания. Е.А. Намолов с помощью тектонофизического анализа системы «элементарная трещина – рудовмещающий шов (разрыв)» дал генетическое объяснение морфологии рудных кварцевых жил (включая жилу № 30) и условиям формирования вмещающих их зон разломов. Было установлено, что рудовмещающие разрывы представляют собой сочетания трещин скола и отрыва, возникающие при определенных положениях эллипсоида деформации в обстановке одностороннего горизонтального сжатия. Неоднократные внутриминерализационные подвижки обусловили полосчатые текстуры руд и многочисленные включения вмещающих пород в кварцевом матриксе жил.Сферические частицы обладают зональным строением и состоят из металлических ядер и внешних сплошных или прерывистых оболочек, толщиной от 10 до 400 мкм (рис. 2, рис. 3). Ядра в основном сложены самородным Fe с примесью Fe, Mn, Al (таблица), содержания которых обычно не превышают 1.0–1.5 мас. %.Характерными особенностями минерального состава оболочек рассматриваемых сфероидных микрочастиц являются (таблица):– широкое распространение графитовой матрицы, включающей минералы различных классов, кроме самородных;– наличие пирита в группе рудных оксидов Fe, Mn, Cr, Ti;– присутствие большой группы карбонатных минералов;– наличие полевых шпатов и натросилита среди силикатов;– присутствие минерала состава CaBr2;– наличие мономинеральных кварцевых оторочек.Следствием динамометаморфизма, т.е. деформационного или механохимического преобразования пород Ирокиндинского шарьяжа, а также автохтона (толща пород Келяно-Ирокиндинского пояса), является образование газоводной («гидротермальной») системы, способной к формированию рудных сферических частиц с низкотемпературными минеральными каемками.Главная особенность строения сферических микрочастиц Ирокинды заключается в резком контрасте условий кристаллизации металлических ядер и их оторочек. Аналогичные условия, приводящие к образованию сходных по составу с рассматриваемыми сферулами контрастных минеральных ассоциаций, характеризуют газоводолитокластитовую и газоводную стадии формирования грязевых вулканов. Для этих стадий предложен кавитационный механизм образования металлических сферических частиц Fe, Fe-Cr и другого состава, сопровождающийся горением (пирогенный расплав) и пиролизом углеводородных компонентов флюида. Такой механизм, за исключением происхождения расплава (в нашем случае фрикционный), в наибольшей степени соответствует фактическим данным. Образование сфероидов осуществлялось, вероятно, в дорудную стадию формирования кварцевых жил.Обнаруженные и изученные высокотемпературные металлические сферические микрочастицы можно рассматривать как своеобразные индикаторы условий функционирования рудообразующей системы динамометаморфического типа, продуцирующей золоторудную минерализацию на Ирокиндинском месторождении. По строению и вещественному составу они сильно отличаются от микросферул шлаков других забайкальских золоторудных месторождений (Сухой Лог – черносланцевая и Первенец – малосульфидная золотокварцевая рудные формации), также принадлежащих к динамогенному генетическому типу. Однако рудообразующие системы сравниваемых месторождений объединяют два фактора, способствующие образованию сферических микрочастиц: высокая тектоническая активность, заключающаяся в неоднократном (импульсивном) проявлении тектонических подвижек, и иницируемые ею условия нестабильности режима давления. Следствием последнего является гетерогенизация газоводного флюида, в свою очередь обусловливающая появление механизмов кавитации и пенной флотации.

Quantum Entanglement in Nitrosyl Iron Complexes

Recent magnetic susceptibility measurements for polycrystalline samples of binuclear nitrosyl iron complexes [Fe_2(C_3H_3N_2S)_2(NO)_4] (I) and [Fe_2(SC_3H_5N_2)_2(NO)_4] (II), suggest that quantum-mechanical entanglement of the spin degrees of freedom exists in these compounds. Entanglement E exists below the temperature T_E that we have estimated for complexes I and II to be 80-90 and 110-120 K, respectively. Using an expression of entanglement in terms of magnetic susceptibility for a Heisenberg dimer, we find the temperature dependence of the entanglement for complex II. Having arisen at the temperature T_E, the entanglement increases monotonically with decreasing temperature and reaches 90-95% in this complex at T=25 K, when the subordinate effects are still small.Comment: 8 page

The transcriptional repressor protein NsrR senses nitric oxide directly via a [2Fe-2S] cluster

The regulatory protein NsrR, a member of the Rrf2 family of transcription repressors, is specifically dedicated to sensing nitric oxide (NO) in a variety of pathogenic and non-pathogenic bacteria. It has been proposed that NO directly modulates NsrR activity by interacting with a predicted [Fe-S] cluster in the NsrR protein, but no experimental evidence has been published to support this hypothesis. Here we report the purification of NsrR from the obligate aerobe Streptomyces coelicolor. We demonstrate using UV-visible, near UV CD and EPR spectroscopy that the protein contains an NO-sensitive [2Fe-2S] cluster when purified from E. coli. Upon exposure of NsrR to NO, the cluster is nitrosylated, which results in the loss of DNA binding activity as detected by bandshift assays. Removal of the [2Fe-2S] cluster to generate apo-NsrR also resulted in loss of DNA binding activity. This is the first demonstration that NsrR contains an NO-sensitive [2Fe-2S] cluster that is required for DNA binding activity

НАЛОЖЕННЫЕ ДЕФОРМАЦИИ ГЕРЦИНСКОГО ВРЕМЕНИ В СТРУКТУРЕ МЕСТОРОЖДЕНИЯ ГОЛЕЦ ВЫСОЧАЙШИЙ (БАЙКАЛО-ПАТОМСКИЙ ПОЯС), 40AR/39AR ДАННЫЕ

The paper presents the results of the detailed structural analysis and 40Ar/39Ar dating of the deformations in the Golets Vysochaishii deposit area. The geological and structural studies showed the folded-deformation sequence from large lying folds through axial-plane cleavage formation and cleavage to quartz-filled fractures. The 40Ar/39Ar dating of syntectonic sericite yielded the ages of two Hercynian tectonic impulses – 340 and 320 Ma. This stage is characterized by the earlier-known successive complication of the Early Paleozoic fold-nappe structure of the area. Analysis has been made on four samples taken from different sites and characterized by different sets of deformational structures. The 40Ar/39Ar age of 340 Ma reflects the formation of small-size folds as a result of interlayer sliding and sliding along the cleavage axial planes. The 40Ar/39Ar age of 320 Ma reflects the formation of discretely manifested crenulation cleavage and low-Au, low-sulfidation quartz veins oriented obliquely to the elements of bedding and axial-plane cleavage.В работе приведены результаты детального структурного анализа и изотопно-геохронологического 40Ar/39Ar датирования деформаций, проявленных на территории месторождения Голец Высочайший. В ходе выполнения геолого-структурных работ установлена последовательность проявления складчатых деформаций от крупных лежачих складок через формирование кливажа осевой поверхности и кренуляционного кливажа до разрывных нарушений, заполненных кварцевым материалом. С помощью 40Ar/39Ar датирования синтектонического серицита удалось установить возраст двух тектонических импульсов герцинского этапа – 340 и 320 млн лет. Этот этап характеризуется последовательным осложнением покровно-складчатой структуры района, сформированной на раннепалеозойском этапе, известном по литературным данным предшественников. Проанализированы четыре пробы, отобранные в различных местах и характеризующиеся различным набором деформационных структур. 40Ar/39Ar возраст 340 млн лет отражает формирование мелкой складчатости в результате межслоевых скольжений и скольжений по плоскостям кливажа осевой поверхности. 40Ar/39Ar возраст 320 млн лет отражает формирование дискретно проявленного кренуляционного кливажа и слабозолотоносных, малосульфидных кварцевых жил, занимающих секущее положение по отношению к элементам слоистости и кливажа осевой поверхности

Nonlocal interactions prevent collapse in negative scattering length Bose-Einstein gases

We study the effect of nonlocality on the collapse properties of a self-focusing Nonlinear Schr\"odinger system related to Bose-Einstein condensation problems. Using a combination of moment techniques, time dependent variational methods and numerical simulations we present evidences in support of the hypothesis that nonlocal attractively interacting condensates cannot collapse when the dominant interaction term is due to finite range interactions. Instead there apppear oscillations of the wave packet with a localized component whose size is of the order of the range of interactions. We discuss the implications of the results to collapse phenomena in negative scattering length Bose-Einstein condensates

On the quest for selective constraints shaping the expressivity of the genes casting retropseudogenes in human

<p>Abstract</p> <p>Background</p> <p>Pseudogenes, the nonfunctional homologues of functional genes are now coming to light as important resources regarding the study of human protein evolution. Processed pseudogenes arising by reverse transcription and reinsertion can provide molecular record on the dynamics and evolution of genomes. Researches on the progenitors of human processed pseudogenes delved out their highly expressed and evolutionarily conserved characters. They are reported to be short and GC-poor indicating their high efficiency for retrotransposition. In this article we focused on their high expressivity and explored the factors contributing for that and their relevance in the milieu of protein sequence evolution.</p> <p>Results</p> <p>We here, analyzed the high expressivity of these genes configuring processed or retropseudogenes by their immense connectivity in protein-protein interaction network, an inclination towards alternative splicing mechanism, a lower rate of mRNA disintegration and a slower evolutionary rate. While the unusual trend of the upraised disorder in contrast with the high expressivity of the proteins encoded by processed pseudogene ancestors is accredited by a predominance of hub-protein encoding genes, a high propensity of repeat sequence containing genes, elevated protein stability and the functional constraint to perform the transcription regulatory jobs. Linear regression analysis demonstrates mRNA decay rate and protein intrinsic disorder as the influential factors controlling the expressivity of these retropseudogene ancestors while the latter one is found to have the most significant regulatory power.</p> <p>Conclusions</p> <p>Our findings imply that, the affluence of disordered regions elevating the network attachment to be involved in important cellular assignments and the stability in transcriptional level are acting as the prevailing forces behind the high expressivity of the human genes configuring processed pseudogenes.</p

Diversification of Genes Encoding Granule-Bound Starch Synthase in Monocots and Dicots Is Marked by Multiple Genome-Wide Duplication Events

Starch is one of the major components of cereals, tubers, and fruits. Genes encoding granule-bound starch synthase (GBSS), which is responsible for amylose synthesis, have been extensively studied in cereals but little is known about them in fruits. Due to their low copy gene number, GBSS genes have been used to study plant phylogenetic and evolutionary relationships. In this study, GBSS genes have been isolated and characterized in three fruit trees, including apple, peach, and orange. Moreover, a comprehensive evolutionary study of GBSS genes has also been conducted between both monocots and eudicots. Results have revealed that genomic structures of GBSS genes in plants are conserved, suggesting they all have evolved from a common ancestor. In addition, the GBSS gene in an ancestral angiosperm must have undergone genome duplication ∼251 million years ago (MYA) to generate two families, GBSSI and GBSSII. Both GBSSI and GBSSII are found in monocots; however, GBSSI is absent in eudicots. The ancestral GBSSII must have undergone further divergence when monocots and eudicots split ∼165 MYA. This is consistent with expression profiles of GBSS genes, wherein these profiles are more similar to those of GBSSII in eudicots than to those of GBSSI genes in monocots. In dicots, GBSSII must have undergone further divergence when rosids and asterids split from each other ∼126 MYA. Taken together, these findings suggest that it is GBSSII rather than GBSSI of monocots that have orthologous relationships with GBSS genes of eudicots. Moreover, diversification of GBSS genes is mainly associated with genome-wide duplication events throughout the evolutionary course of history of monocots and eudicots

Coordinate and redox interactions of epinephrine with ferric and ferrous iron at physiological pH

Coordinate and redox interactions of epinephrine (Epi) with iron at physiological pH are essential for understanding two very different phenomena - the detrimental effects of chronic stress on the cardiovascular system and the cross-linking of catecholamine-rich biopolymers and frameworks. Here we show that Epi and Fe3+ form stable high-spin complexes in the 1:1 or 3:1 stoichiometry, depending on the Epi/Fe3+ concentration ratio (low or high). Oxygen atoms on the catechol ring represent the sites of coordinate bond formation within physiologically relevant bidentate 1:1 complex. Redox properties of Epi are slightly impacted by Fe3+. On the other hand, Epi and Fe2+ form a complex that acts as a strong reducing agent, which leads to the production of hydrogen peroxide via O-2 reduction, and to a facilitated formation of the Epi-Fe3+ complexes. Epi is not oxidized in this process, i.e. Fe2+ is not an electron shuttle, but the electron donor. Epi-catalyzed oxidation of Fe2+ represents a plausible chemical basis of stress-related damage to heart cells. In addition, our results support the previous findings on the interactions of catecholamine moieties in polymers with iron and provide a novel strategy for improving the efficiency of cross-linking.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3040