Search

The paper describes Ca–Pb phosphates—pyromorphite and phosphohedyphane—from the oxidation zone of barite–lead (calcite–barite–galena) ores of the Ushkatyn-III deposit in Central Kazakhstan. Both minerals occur equally frequently within the deposit. Lead phosphates coexist with ore minerals unaltered in the subsurface setting (galena, pyrite, barite, calcite, rhodochrosite, chamosite, etc.), and minerals of highly oxidized ores (cerussite, montmorillonite, kaolinite, goethite, etc.). As the processes of supergene processes develop (during the transition from weakly to highly oxidized ores), the compositions of newly formed phosphates change regularly in the following consequence: phosphohedyphane → rhythmically zonal Ca–Pb phosphate → pyromorphite. At the same time, the habit of mineral crystals changes from dipyramidal-prismatic through elongated prismatic (barrel-shaped) to pinacoidal-prismatic (short-columnar). Crystallization of pyromorphite is possible already at very low contents of lead, phosphorus and chlorine in the solution. The main source of chlorine is groundwater; phosphorus is coming from the organic matter of the soil cover overlying ore-bearing deposits. The features of the chemical composition and crystal structure of Ca–Pb phosphates, as well as the nature of their assemblages, suggest the presence of a discontinuity in isomorphic miscibility in the following series: pyromorphite–phosphohedyphane and phosphohedyphane–chlorapatite. [ABSTRACT FROM AUTHOR]

The Ushkatyn-III deposit in Central Kazakhstan is a complex object that combines industrially significant deposits of (a) hydrothermal lead and barite ores, (b) hydrothermal-sedimentary iron and manganese ores, (c) supergene (oxidized) lead and barite ores. The mineralogy of the oxidation zone of barite–lead ores was studied. The non-oxidized hydrothermal barite–lead ores are almost entirely composed of calcite, barite, and galena; typical secondary minerals are quartz, pyrite, muscovite–phengite, potassic feldspar, albite, and fluorite; the most characteristic accessory minerals are hematite, sphalerite, chalcopyrite, chamosite, and apatite. Fe–Mn carbonates (rhodochrosite and Mn-rich siderite) occur sporadically in ores. The following processes occur in the oxidation zone: (1) dissolution of calcite; (2) replacement of galena by cerussite and lead phosphates (pyromorphite and phosphohedyphane); (3) formation of montmorillonite and kaolinite due to decomposition of feldspars, chamosite, and mica; and (4) formation of goethite due to the alteration of pyrite and, in part, hematite. Barite is stable in the oxidation zone but it was subject to local recrystallization and redistribution. The sequence of main mineralogical changes in ores was as follows: (1) assemblages of primary ores: calcite + barite + galena ± quartz ± pyrite ± hematite ± feldspars ± muscovite ± chamosite; (2) assemblages of weakly oxidized ores: calcite + barite + cerussite + pyromorphite (phosphohedyphane) + quartz ± galena ± pyrite ± hematite ± goethite ± muscovite ± chamosite ± montmorillonite; and (3) assemblages of highly oxidized ores: barite + cerussite + pyromorphite (phosphohedyphane) + quartz + montmorillonite + kaolinite ± galena ± hematite ± goethite ± muscovite. The bulk of the oxidation zone is composed of highly oxidized ores. Mn–Fe carbonates are less soluble than calcite. Therefore, at the early stages of the development of the oxidation zone, they occur in association with galena, barite, cerussite, phosphohedyphane, quartz, chamosite, and some other minerals. Rhodochrosite and Mn-rich siderite are completely replaced at late stages by oxides of tri- and tetravalent manganese. [ABSTRACT FROM AUTHOR]

The purpose of this work was to synthesize hexahydrate aluminum selenite Al2(SeO3)3⋅6H2O (analogous to the mineral alfredopetrovite) and study its solubility in water. Al2(SeO3)3⋅6H2O is synthesized from AlCl3 and Na2SeO3 solutions at room temperature and atmospheric pressure. The obtained samples were studied using powder diffractometry, infrared and Raman spectroscopy, energy-dispersive X-ray microanalysis, nuclear magnetic resonance spectroscopy, and complex thermal analysis. Solubility was determined by isothermal saturation in ampoules at 25°C. Solubility products were calculated using Geochemist's Workbench software package (GMB 9.0, SpecE8 program). As a result of the calculation, the average value logKsp[Al2(SeO3)3⋅6H2O] = –28.3 ± 0.5 was obtained. An Eh–pH diagram is constructed for the Al–Se–H2O system, which was used to analyze the stability of alfredopetrovite in near-surface conditions. [ABSTRACT FROM AUTHOR]

Physicochemical properties and vertical distribution patterns of clay minerals in the weakly differentiated permafrost-affected soils of the Kolyma Lowland have been studied. These soils are developed under conditions of cold ultracontinental climate within a broad range of landscapes: coastal marsh, alas meadows on the plain composed of the ice complex deposits, and typical northern taiga. Despite the fact that weathering processes are weakly developed at high latitudes, certain features of pedogenic transformation of the initial chlorite–illite association have been identified. These are the presence of (i) vermiculite in the acidic soil horizons of the alas meadow and zonal northern taiga landscapes and (ii) iron hydroxide (lepidocrocite) in the profile of the marsh meadow soil. The soils of zonal taiga woodland are classified as cryozems according to the new Russian profile-genetic soil classification system; their classification position does not cause doubt. Oppositely, the classification of weakly differentiated and differently gleyed soils of intrazonal landscapes (alases and marsh meadows) is open to argument and should be further clarified. [ABSTRACT FROM AUTHOR]

The Ushkatyn-III in Central Kazakhstan is a weakly metamorphosed hydrothermal–sedimentary ore deposit of the Atasu type. For such objects, an assemblage of stratiform bodies of iron–manganese and polymetallic (lead–zinc and barite–lead) ores is typical. At the Ushkatyn-III deposit, there are iron, manganese, and barite–lead ores located in the Upper Devonian limestones. Iron and manganese ore have been the study objects. Iron ores are composed of hematite, calcite, and quartz. Two mineralogical types of manganese ores are distinguished: hausmannite and braunite. Hausmannite ores are composed of hausmannite, rhodochrosite, calcite, tephroite, sonolite, alleghanyite, and friedelite. Braunite ores include braunite, calcite, quartz, albite, rhodonite, friedelite, and rhodochrosite. The mineral composition of these ores was formed during transformation of metalliferous deposits that initially accumulated iron and manganese in form of oxides and hydroxides of Fe3+ and Mn3+/Mn4+ at T ≈ 250° and P ≈ 2 kbar. The organic matter content in the rocks controlled postdepositional processes. Braunite ores were formed under oxidizing conditions, while hausmannite ores were formed under reducing ones. Hydrated silicates, such as caryopilite, friedelite, pennantite, clinochlore, chamosite, and parsettensite, are indicators of low temperatures of metamorphism. There are a large number of accessory minerals found in iron and manganese ores. Among them, minerals containing B, F, S, V, Cu, Zn, As, Sr, Ag, Sb, Te, Ba, Hb, Pb and rare-earth elements, including Mn–Zn and Mn–Pb phases – zinc-bearing hausmannite and jacobsite, hetaerolite, kentrolite, and pyrobelonite—are widely distributed. The spatial–age relationships between the minerals indicate the synchronous accumulation of Fe, Mn, Zn, As, Ba, Pb, and other elements in the primary metalliferous sediments and their subsequent local redistribution during metamorphism, which led to crystallization of their phases. Presence of minerals of nonferrous metals and barium makes manganese ores related to barite–lead ores occurring in their immediate vicinity. Both ore types were likely formed simultaneously as products of the evolution of the single hydrothermal system. [ABSTRACT FROM AUTHOR]

A Zr–BDC metal–organic framework was synthesized by the solvothermal method using N,N‑dimethylformamide as an organic solvent at the temperature 110°С. The adsorbent thus obtained is characterized by a developed porous structure with specific BET surface SBET = 1060 m2/g, micropore volume W0 = 0.44 cm3/g, and average micropore radius х0 = 0.54 nm, which is indicative of a potentially effective adsorbent for adsorbed natural gas storage systems. The shaping parameters were determined for the Zr–BDC-based composites with polyvinyl alcohol as a binder and without the use of any binder at various compacting pressures. The influence of the shaping pressure on the packing density and structural and energy characteristics of the obtained samples was investigated. Based on the Dubinin theory of volume filling of micropores, the pressure dependences of the methane deliverable capacity both in the initial powdered and shaped Zr–BDC adsorbents at the temperatures of 243, 273, and 303 K were calculated for the pressures up to 100 bar. The deliverable volumetric methane capacity of the adsorption system based on the shaped Zr–BDC samples was measured in the specified thermodynamic conditions. [ABSTRACT FROM AUTHOR]

The feasibility of using molecular genetic markers associated with thyroid neoplasms and more aggressive course of the disease is now actively studied. We analyzed the diagnostic value of somatic mutations in the hot spots of BRAF, KRAS, KRAS, EIF1AX, and TERT genes in histological material from 153 patients with thyroid gland neoplasms. BRAF mutations (exon 15, codon area 600-601) were found in 54 patients, NRAS mutations (exon 3, codon 61) were detected in 12 patients; mutations KRAS, TERT, and EIF1AX genes were not detected. [ABSTRACT FROM AUTHOR]

A variety of caryopilite enriched in Mg and Al from the goethite–neotocite–rhodochrosite ores of the Mazul manganese deposit in Krasnoyarsk Krai is described. The mineral occurs as sheaf-like and fibrous aggregates of fine-lamellar individuals intimately intergrown with goethite, hematite, rhodochrosite, and neotocite. The optical parameters of caryopilite are: Z = yellow, X = pale yellow, β ≈ 1.60, γ – α ≈ 0.010 – 0.015, and parallel extinction. The average chemical composition corresponds to the empirical formula (Mn1.95Mg1.61 Al0.58◻0.23)5.00[(Si3.88Al0.12)4.00O10](OH)6, where ◻ is vacancy. The unusually high Mg concentration and elevated Al content allow identification of a new aluminum–magnesium variety of caryopilite. It replaces sedimentary neotocite at low temperatures. It is suggested that at increasing temperature this variety of caryopilite loses Mg and Al, which incorporate into Mg–Mn chlorite and spessartine. [ABSTRACT FROM AUTHOR]

The gas chromatographic properties of the porous methacrylate polymers, copolymers of 2,3-epoxypropyl methacrylate (2,3-EPMA) and ethylenedimethacrylate (EDMA), modified by silver nanoparticles were studied. The modification of the initial methacrylate copolymer by silver nanoparticles almost does not change the ability of the copolymer to dispersion interaction but results in an increase in polarity and enhances the possibility of specific interactions to occur. The aminated copolymer (copolymer of 2,3-EPMA and EDMA modified by diethylenetriamine using the reaction at the epoxy group) modified by silver nanoparticles demonstrates a higher ability to dispersion interactions and a lower polarity. Possibly, the sorption of silver particles on amino groups of the polymer is a reason for decreasing polarity of the polymer. [ABSTRACT FROM AUTHOR]

Size-exclusion chromatography has been employed to determine the sizes of palladium and silver nanoparticles synthesized by the radiation-chemical method in micellar solutions of a surfactant (AOT) at different degrees of hydration ω0 = [H2O]/[AOT]. Silver and palladium nanoparticle sizes are in the ranges of 1.5–5.3 and 1.5–3 nm. The results obtained have been compared with the data of atomic force microscopy. It has been shown that the sizes of nanoparticles synthesized in micellar solutions must be corrected with allowance for the contribution of micelle shell thickness. [ABSTRACT FROM AUTHOR]

Abstract: A metal-organic framework, Fe-BDC, was synthesized by solvothermal method from iron salt and terephthalic acid using N,N-dimethylformamide as the solvent. The data from the study of structural-energy characteristics calculated by the Dubinin-Radushkevich, Kelvin, and BET equations are given. The resulting Fe-BDC sample has a specific surface area of SBET = 2240 m2/g and a specific micropore volume of W0 = 0.83 cm3/g. The morphological and X-ray characteristics of this sample were studied. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms of cadmium and selenium behavior under near-surface conditions is very important for solving certain environmental problems. The principal aim of this study is physicochemical analysis of the formation conditions of synthetic cadmium selenite CdSeO · HO and experimental investigation of its thermal stability and dehydration and dissociation mechanisms. The synthesis was performed by boiling-dry aqueous solutions of cadmium nitrate and sodium selenite. The obtained samples were identified with electron microprobe and powder X-ray diffraction. Complex thermal analysis (thermogravimetry and differential scanning calorimetry) have shown that CdSeO · HO is dehydrated at 177-241°C in two stages, apparently corresponding to the formation of CdSeO · 2/3HO. The Eh-pH diagrams were calculated using the Geochemist's Workbench (GWB 9.0) software package. The Eh-pH diagrams have been calculated for the Cd-Se-НО and Cd-Se-CO-HO systems for the average content of these elements in underground waters. The formation of cadmium selenite, CdSeO · HO in the oxidation medium is quite possible. The existence of CdSeO is possible at high temperature. [ABSTRACT FROM AUTHOR]

The morphology and chemical and physicochemical properties of paleosols buried at the Upper Paleolithic multilayered site Kostenki-1 in Kostenki-Borshchevo district of Voronezh oblast were studied. Four in situ paleosols formed 20-40(45) ka ago were separated in the archaeological excavation. Together with the surface soils, they characterized two different epochs of pedogenesis-the interstadial and interglacial (Holocene) epochs-and three shorter cycles of pedogenesis. The traces of human occupation in the studied hollow in the Late Paleolithic were found in the layers corresponding to the interstadial epoch. The buried paleosols had a simple horizonation: A(W)-C. A shallow thickness of the soil profiles could be due to relatively short periods of pedogenesis and to the shallow embedding by the carbonate geochemical barrier. The degree of the organic matter humification in the paleosols varied from 0.6 to 1.5, which corresponded to the mean duration of the period of biological activity of 60 to 150 days per year characterizing the climatic conditions of the tundra, taiga, forest-steppe, and steppe natural zones. In the excavation Kostenki-1 (2004-2005), soil-sediment sequences composed of five series of lithological layers with soil layers on top of them were found. Their deposition proceeded in two phases-the water phase and the aerial phase-that predetermined the morphology and composition of the soil-sediment sequences. The history of sediment accumulation in the studied hollow consisted of five stages. Similar morphologies and compositions of the soil-sediment sequences corresponding to these stages attest to the cyclic pattern of their development. The stages of sedimentation and soil formation corresponded to cyclic climate fluctuations with changes in the temperature and moisture conditions. A comparative analysis of the morphology and properties of the paleosols and soil-sediment sequences made it possible to characterize the environmental conditions of ancient humans and the dynamics of the climate during the past 50 ka. [ABSTRACT FROM AUTHOR]

Polyphase geoceramic matrices of the (silico)phosphate type for joint immobilization of the strontium-cesium and rare earth fractions of high-level waste with residual actinide content were synthesized. The charge components were iron oxide, technical-grade phosphoric acid, and apatite ore dressing tails. The synthesis method involves fine dispersion of the starting materials and two-step ceramization at 920 and 910°C for 20 min. The total content of the radionuclides in the matrix is on the level of 15 wt %. The cesium leach rate under the conditions of kinetic control (at 90°C) is 5 × 10 g cm day. [ABSTRACT FROM AUTHOR]

The objective of this paper is to study the thermal stability of the synthetic analog of chalcomenite, CuSeO · 2HO, and its dehydration and dissociation, in an experimental context. The study has been carried out by a comprehensive application of thermogravimetry (TG), differential scanning calorimetry (DSC), and high-temperature X-ray diffraction at a temperature range of 25-600°C. It has been established that CuSeO · 2HO dehydrates at 202-264°C in three stages corresponding to the formation of intermediate CuSeO · 2HO and CuSeO · 1/3HO hydrate phases. At 480-595°C anhydrous CuSeO breaks down into CuO and SeO via the formation of a CuO(SeO) phase. Enthalpies of the reactions at each stage of the CuSeO · 2HO dehydration and CuSeO dissociation have been determined and their kinetic analysis has been carried out. [ABSTRACT FROM AUTHOR]

This paper deals with some new arguments corroborating the absence of carbonyl moieties [1] in the chemical structure of hypercrosslinked polystyrenes in spite of the high intensity of the absorption band around 1700 cm in their FTIR spectra. Three additional facts testify to the benefit of this conclusion. First is the appearance of the absorbance band at 1700 cm in a computer-simulated IR spectrum of a rigid highly crosslinked model network that contains no C=O groups. Second, thermal degradation of the hypercrosslinked network with a formal 500% crosslinking density results in emergence in its mass-spectrum of benzene, alkylbenzenes and hydrogen chloride, only. Third, testing the above hypercrosslinked polystyrene as a stationary phase in a GC column shows the polymer to retain aliphatic hydrocarbons, alcohols and ketones largely by dispersion interactions, thus revealing no polar oxygen-containing groups on its surface. [ABSTRACT FROM AUTHOR]

Multiple myeloma (MM) is a deadly hematopoietic malignancy characterized by proliferation of malignant plasma cells in the bone marrow (BM) and bone disease. Interactions between myeloma and BM cells facilitate tumor progression and resistance to therapies. CXCR4 and its ligand Stromal cell-derived factor-1 (SDF-1) have a primary role in this process and are associated with poor prognosis. The Notch pathway is active in myeloma cells, resulting in increased proliferation, resistance to apoptosis and osteolytic activity. We hypothesized that the CXCR4/SDF-1 axis mediates the effects of Notch signals in myeloma cells. Here we show that Notch positively controls CXCR4/SDF-1 expression and functions in myeloma cell lines, and that forced CXCR4 activation partially rescues tumor cells from the outcomes of Notch inhibition. Additionally, we provide evidences that Notch blocking in vivo significantly reduces BM infiltration by human myeloma cells in mouse xenografts. This is the first evidence that a Notch-targeted approach effectively prevents MM cell migration, proliferation and resistance to apoptosis by reducing CXCR4 and SDF-1 levels. [ABSTRACT FROM AUTHOR]

Multiple myeloma is a deadly hematopoietic malignancy. Despite therapeutic advances such as autologous stem cell transplantation and novel chemotherapeutics, multiple myeloma remains incurable. Multiple myeloma cell localization in the bone marrow and the cross-talk with the bone niche trigger dramatic alterations in the bone marrow microenvironment critical for tumor progression, resistance to therapies and osteolytic bone destruction. It does not surprise that the molecular bases of such fatal interaction are under examination as source of novel potential pharmacological targets. Among these, the Notch family of receptors and ligands has gained growing interest in the recent years because of their early deregulation in multiple myeloma and their ability to affect multiple features of the disease, including tumor cell growth, drug resistance, angiogenesis and bone lesions. This review will explore the evidences of Notch deregulation in multiple myeloma, the state of the art of the currently known roles of its signaling in the fatal interaction between multiple myeloma cells, extracellular matrix and cells in the bone marrow stroma. Finally, we will present recent findings concerning the arguments for or against a therapy addressed to Notch signaling inhibition in the cure of multiple myeloma. [ABSTRACT FROM AUTHOR]

Thermal deformations and polymorphic transformations of even long chain monoclinic normal paraffins CH and CH (homological purity 97-99%) are studied. Thermal deformations and temperature limits of the existence of crystalline (1 M and 2 M), low-temperature rotationally crystalline triclinic ( Tc), monoclinic ( M), and orthorhombic ( Or) and high-temperature rotationally crystalline hexagonal ( H) phases of these n-paraffins are estimated by the character of changes in their diffraction patterns and unit cell parameters (thermal X-ray diffraction). The molecular structure and conformational composition of these n-paraffins in different phase states are determined (IR spectroscopy). In order to determine the temperatures of phase transitions differential scanning calorimetry is also applied. The data of all three methods are in good agreement with each other. The initial sample of CH n-paraffin at room temperature is characterized by a two-layer monoclinic 2 M crystalline modification. When the melt is rapidly cooled, it crystallizes in monolayer monoclinic 1 M and orthorhombic Or modifications (two-phase mixture 1 M+ Or). The initial sample of CH n-paraffin at room temperature is characterized by the monolayer monoclinic modification 1 M. When the melt is rapidly cooled, as well as CH n-paraffin, it crystallizes in monolayer monoclinic 1 M and orthorhombic Or modifications (two-phase mixture 1 M+ Or). It is found that both n-paraffin undergo irreversible polymorphic transformations from the crystalline state cryst to the low-temperature rotationally crystalline state rot.1. For CH n-paraffin the transition is performed by the scheme 2 M → M → Or, and for CH n-paraffin it is performed by the scheme 1 M → Tc. Both paraffins do not undergo the transition to the high-temperature rotationally crystalline state rot.2 (hexagonal phase H), similarly to monoclinic CH n-paraffin studied previously. These and previously obtained data allow us to consider that as the molecular chain length increases, differences in the polymorphic modification of initial crystalline phases cease to be significant and the sequence of polymorphic transformations is mainly determined by the length of the molecule. [ABSTRACT FROM AUTHOR]

The possibilities of diffuse and specular reflectance Fourier-transform infrared spectroscopy in long-term corrosion monitoring are studied. A 15-week period of interaction between carbon tetrachloride and a commercial aluminum sheet is followed. Analysis of the results obtained reveals a complex and multistage character of the interaction between CCl and aluminum surface. The final product of the reaction is shown to be chlorine-containing hydrocarbon, which is strongly bound to the metal surface. [ABSTRACT FROM AUTHOR]

Copper deficiency in adult rats was induced by addition of silver chloride to the feed. The concentrations of silver, copper, iron, and zinc and relative activity of genes for copper transporting proteins and copper enzymes were measured in the cortex, cerebellum, hippocampus, amygdala, pituitary gland, and hypothalamus. Silver was accumulated only in the hypothalamic—pituitary system. These changes were accompanied by a decrease in the concentration of copper and increase in the contents of iron and zinc. Activity of genes for copper transport enzymes (high-affinity copper transporter; and two copper transport ATPases, ATP7A and ATP7B) and copper enzymes that were formed in the intracellular secretory pathway did not decrease in the brain of rats with copper deficiency. Relative activity of genes for intracellular copper enzymes (Cu2+/Zn2+ superoxide dismutase and subunit IV of cytochrome c oxidase), concentration of immunoreactive polypeptides of superoxide dismutase, and enzymatic activity of superoxide dismutase remained unchanged under these conditions. [ABSTRACT FROM AUTHOR]

Tissue-specific regulation of the expression of ceruloplasmin (Cp) gene, which encodes major copper-containing extracellular glycoprotein was investigated. A decrease of the Cp concentration associated with copper amounts in milk during the first 3 days of lactation was used as phenotypic index for evaluating the Cp enzyme activity in the mammary gland. Computer analysis of mammalian Cp gene promoter region has revealed conserved sequences of cis-elements, which potentially were capable of regulating the enzyme activity. It has been shown that changes in the nucleotide sequence of specific transcriptional factor binding sites located at 5′-end of Cp gene were associated with disturbance of the regular downregulation of Cp gene activity during lactation. [ABSTRACT FROM AUTHOR]

The article reports on the results of a study of the effect of silver ions on copper metabolism and expression of genes encoding copper transport proteins in rat liver. A description of the experimental set-up and measurement methods is presented. The study concluded that the copper transporters promote successful uptake of silver ions, isoelectronic to copper ions by hepatocytes.

Natural normal paraffin hydrocarbons C n H2 n + 2 ( n = 17–41) of a biological origin were investigated in terms of their composition, structure, polymorph modification, and thermal phase transition. Paraffin compositions were studied from beeswax (honeycombs and their cappings), plant wax (apple and pumpkin rinds), as well as from different parts of rat cerebrum (cortex, subcortex, brainstem, cerebellum, cerebral hemispheres, myelin, chromatin, etc.). X-ray diffraction analysis (XRD), chromatography, and high-temperature XRD, as well as original analytical methods elaborated upon by the authors, were used. The beeswax paraffin composition that corresponds to the six-component solid solution with a superperiodic four-layer orthorhombic cell was subjected to experimental modeling for the first time. The prepared mixture simulated a paraffin composition ( n = 23, 25, 27, 29, 31, 33) and the asymmetric distribution of homologues by n. [ABSTRACT FROM AUTHOR]

Thermal deformations and polymorphic transformations of two long-chain evennumbered normal paraffins C26H54 and C28H58 were studied by thermal X-ray diffraction (temperature step is tenths of a degree), infrared spectroscopy (temperature step is 1–5°), and differential scanning calorimetry (temperature step is 2° in a sample heating melt cooling mode. The samples are characterized by high homologous purity (99.0%) and belong to so-called “boundary” n-paraffins. The starting C26H54 n-paraffin sample is a triclinic modification at room temperature ( Tc cryst). When quickly cooled, the melt crystallizes as the triclinic Tc cryst and monoclinic monolayer 1 M cryst forms (two-phase mixture Tc cryst + 1 M cryst). The starting C28H58 n-paraffin sample is a double-layer monoclinic modification 2 M cryst at room temperature. Crystallization from hexane or slow cooling of a melt leads to a monolayer monoclinic form 1 M cryst. Thermal deformations and temperature ranges of existence of the crystalline forms ( Tc cryst, 1 M cryst, and 2 M cryst), low-temperature rotator crystalline orthorhombic form ( Or rot.1), and high-temperature rotator crystalline hexagonal ( H rot.2) phases of these n-paraffins were evaluated from changes in their diffraction patterns and unit cell parameters. The molecular structure and the conformational composition of these n-paraffins in different states were found from their IR spectra. Differential scanning calorimetry (DSC) was used to determine the phase transition temperature. Thermal X-ray diffraction, IR, and DSC data agree well with one another. [ABSTRACT FROM AUTHOR]

The putative product of CTR1 ( SLC31A1 according to the Entrez data base) is regarded as the main candidate for an eukaryotic transmembrane copper importer. The tissue-specific function of mammalian CTR1 is still unknown. A quasi-steady-state level of the CTR1 mRNA was assayed by semiquantitative RT-PCR and compared with the copper status in rat organs (liver, cerebellum, choroid plexus, and mammary gland), which differed in copper metabolism during development and differentiation. The CTR1 activity correlated with production of intracellular and extracellular cuproenzymes and deceased in nuclei of mesenchymal cells at high copper concentrations when copper metabolism followed the embryonic pattern. According to phylogenetic analysis, the most conserved regions of CTR1 are transmembrane domains (TMD) 2 and 3, which together contain seven amino acid residues capable of coordinating a copper atom. A model of the cuprophylic channel formed by TMD2 and TMD3 of the CTR1 homotrimer was proposed. In this model, copper is transported through the channel to the cytosolic C-terminal motif His-Cys-His. The ability of His-Cys-His to coordinate Cu(I) was evaluated by molecular modeling (MM+, ZINDO/1). Potential copper transfer from His-Cys-His to the Cys-X-X-Cys Cu (I) motif, present in all cytosol Cu-chaperones, was shown. The role of CTR1 as a donor and an acceptor of copper in higher eukaryotes is discussed. [ABSTRACT FROM AUTHOR]

A study was made of the expression of the ceruloplasmin (Cp) gene, whose product, blue multicopper ferroxidase, acts as a neuron survival factor. Computer analysis predicted an alternative promoter in the 3′-terminal region of intron 2 of the rat Cp gene and showed that transcription from this promoter potentially yields an mRNA coding for a 109-kDa polypeptide. The alternative Cp form starts with a region of 25 amino acid residues encoded by a part of intron 2. From Gly113, its sequence is identical to that of the major Cp form. The in silico data were confirmed experimentally by RT-PCR. The predicted mRNA was found predominantly in the liver and brain of adult rats. Direct sequencing of the PCR product demonstrated the complete identity of the predicted and real mRNA sequences. It was shown in vitro that a Cp-like protein of about 110 kDa is synthesized in the cytosol and accumulates in the absence of mitochondria. The protein was transferred into isolated mitochondria in a reconstructed system. Transport was energy-dependent, was associated with no change in Cp polypeptide length, and required cytosolic factors. Mitochondrial import of the Cp form was probably determined by an internal mitochondrial localization signal, KVVYREFTDSTFRE, corresponding to region 756–769 of mature Cp. The possible role of Cp in mitochondrial iron metabolism is discussed. [ABSTRACT FROM AUTHOR]

Expression of two copper-transporting P1-type ATPases (ATP7A and ATP7B), the CTR1 protein, a high-affinity copper transporter, and ceruloplasmin (Cp), a copper-containing ferroxidase was studied. The level of mRNA of these proteins was determined by RT-PCR analysis, the distribution of polypeptides encoded by these genes was determined by immunoblotting, and the type of cells expressing these genes was identified immunohistochemically. It was found that the major product of Cp gene in the brain is the cell membrane-bound Cp. Secretory Cp, whose molecule contains the greatest number of weakly associated copper atoms, is synthesized in the choroid plexus. CTR1 mRNA is evenly distributed in the brain; however, its content is twice higher in the vascular plexus. TheAtp7agene is active in all brain regions, whereas theAtp7bgene is active only in the hypothalamus. The membrane-bound Cp is expressed in glial cells of all types and in ependyma cells. ATP7B and ATP7A are expressed predominantly in ependymyocytes and neurons, respectively. The organization of copper transport in mammalian brain is discussed. [ABSTRACT FROM AUTHOR]

Immunoblotting has been used to detect ceruloplasmin (Cp) polypeptides in rat mitochondria isolated from the brain, liver, testes, and mammary glands. It has been found that Cp is contained in the matrix and inner membranes of mitochondria, and that its molecular weight corresponds to the nonglycosylated form of the protein. Computer analysis has not identified sequences encoding the signal peptide for mitochondria protein import (SPMPI) in the chromosomal Cp gene of rats. However, the analysis of Cp-encoding sequences from databases has shown the presence of SPMPI nucleotide sequences in the human processed Cp pseudogene. A 984-nt region of the Cp pseudogene is translated in the only reading frame to yield a polypeptide consisting of 328 amino acid residues (aa) that contains a 66-aa SPMPI at its N-terminus. The predicted protein (without SPMPI) is 92% identical to the corresponding Cp fragment and contains 20 amino acid substitutions, including eight significant substitutions. The His-X-His motif characteristic of copper-containing ferroxidases is in the middle of the molecule. The substitution of proline by histidine at position 923 of Cp results in a potential copper-binding site. The transcription product of the Cp pseudogene has been found in cultured HepG2 and HuTu 80 human cells with the use of RT-PCR. A 30-kDa polypeptide interacting with antibodies to human Cp has been found in the mitochondria of HuTu 80 cells. The possible biological role of mitochondrial Cp is discussed. [ABSTRACT FROM AUTHOR]

Presents a study which examined the expression of ceruloplasmin (Cp) pseudogene in cultured human cells. Purpose and function of Cp in the body; Information on the process of transporting iron in cell compartments; Analysis of Cp-like protein in mammalian mitochondria.

In vivo biosynthesis of ceruloplasmin (Cp), a copper-containing glycoprotein, which plays an important role in copper transfer between organs and bidirectional iron transport in vertebrates, was studied in 7-day old rats, which are characterized by the embryonic type of copper metabolism. In addition to the liver, Cp is synthesized in the lungs, brain, and kidneys. In “pulse-chase” experiments it was demonstrated that [14C]-Cp appearance in the blood coincides with the secretion of de novo synthesized Cp from the liver. [14C]-Cp is taken up from the blood stream by cells of the heart, lung, and kidneys and binds to red blood cells, while Cp polypeptide chain is not taken up by the brain cells. Immunoreactive polypeptides of the Cp receptor were found using immunoblotting in plasma membranes of the heart, liver, kidneys, and red blood cells, rather than in the brain. Using the RT-PCR method with selective primers, it was shown that these cells contain molecular forms of Cp-mRNAs programming the synthesis of both secretory Cp and Cp bound to the plasma membrane via a glycosyl phosphatidylinositol anchor. After switching to the adult type of copper metabolism, the blood serum contents of copper and Cp sharply increase, while the Cp content in the cerebrospinal fluid, as measured according to the oxidase and antigen activities, and copper concentration, as determined by atomic absorption spectroscopy, remain low. Ontogenetic features of the system ensuring the copper homeostasis in mammals are discussed. [ABSTRACT FROM AUTHOR]

Using the immunoblotting method, the synthesis of two copper-transporting P1-type ATPases, ATP7A (a candidate for the product of the Menkes disease gene) and ATP7B (a presumed product of the Wilson disease gene), in the yolk sac cells of rat embryos at days 11 and 20 of embryogenesis was demonstrated. Concomitantly, yolk sac cells produce ceruloplasmin, a soluble copper-transporting glycoprotein, a proportion of which in secreted proteins progressively diminishes, attaining 5.2% at day 11 and 3.1% at day 20 of development. At different stages of embryogenesis, yolk sac cells synthesize two molecular forms of [14C]-ceruloplasmin, one of which is secreted towards the embryo, whereas the other, towards the decidual membrane. Two forms of ceruloplasmin secreted in polar directions differ in the rate of secretion. The role of the yolk sac as a key organ controlling the delivery and secretion of copper in the embryo during the postimplantation period is discussed. [ABSTRACT FROM AUTHOR]

The interaction was studied of ceruloplasmin (Cp, EC 1.16.3.1), a copper-containing plasma protein, with two synthetic peptides P15 and P16 whose structures correlate with those of the noncytosolic regions of the copper transfer P1 type ATPase (ATP7A), apparently encoded by the Menkes disease gene ( Atp7a). Pentadecapeptide P15 and hexadecapeptide P16 were synthesized using the solid phase method. They correspond to fragments of two extracellular loops ATP7A, of which one loop is apparently involved in the copper ion transfer (P16) whereas the otheris not (P15). The protein footprinting showed that P16 binds to a fragment of the ceruloplasmin domain 6. Kinetics of the ceruloplasmin-P16 binding was studied by affinity chromatography on P16 immobilized on a macroporous disk, and the K d value (1.5¢10−6 M) of this interaction was determined. The ATP7A involvement in the copper ion transfer to nonhepatocyte cells is discussed. [ABSTRACT FROM AUTHOR]

An individual clone, presumably carrying a 3 bp fragment of ceruloplasmin receptor cDNA was isolated from the expression library of human placenta cDNA using polyclonal specific antibodies to ceruloplasmin receptors. EcoR1-hydrolysate of isolated DNA was cloned in a pTZ19 bacterial vector and sequenced in the forward and reverse direction. The comparison of the revealed sequence with known sequences of human genome revealed its high similarity to ceruloplasmin cDNA. [ABSTRACT FROM AUTHOR]

Adsorption of water vapor on methacrylate copolymers and terpolymers was studied. An increase in the content of the cross-linking agent gives rise to increase in the limiting adsorption of water vapor at the saturation pressure ( a) and to decrease in the concentration of primary adsorption centers. Modification of the initial copolymer containing 60 % of 2,3-epoxypropyl methacrylate (EPMA) monomer and 40 % of cross-linking agent, ethylene dimethacrylate, with diethylenetriamine (DETA) results in an increase in the a value, while modification with C and C alkyl, benzyl, and phenyl groups gives rise to decrease in the a values for the copolymeric sorbents. The concentration of primary adsorption centers ( a) increases considerably on modification of the copolymer with DETA and C groups and decreases markedly on modification with benzyl and phenyl groups. For terpolymers, containing EPMA and styrene, an increase in the styrene/EPMA ratio reduces the a and a values. The copolymer modified with DETA groups possesses the most hydrophilic properties, while the copolymer modified with benzyl group exhibits the most hydrophobic properties. The mechanism of adsorption of water molecules on the polymers is discussed. [ABSTRACT FROM AUTHOR]

The synthesis of an analogue of the organic mineral evenkite included preparation of a mixture of ten individual molecular homologues of normal paraffin C n H2 n + 2 ( n = 19–28), melting of this mixture, and subsequent slow cooling under controlled conditions. The symmetrical distribution of these homologues by the number of carbon atoms in the molecule (dominant homologue n = 23) and the X-ray pattern of synthesized evenkite—a ten-component solid solution of n-paraffins—correspond to the characteristics of natural evenkite. [ABSTRACT FROM AUTHOR]