Search results for: lanthanide complexes

Authors: Surbhi Surbhi, Andrea Erni, Gunter Meister, Harold Cremer, Christophe Beclin

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MicroRNAs (miRNAs) are short 20-23 nucleotide long non-coding RNAs; there are 2605 miRNA in humans and 1936 miRNA in mouse in total (miRBase). The nervous system expresses the most abundant miRNA and most diverse. MiRNAs play a role in many steps during neurogenesis, like cell proliferation, differentiation, neural patterning, axon pathfinding, etc. Moreover, in vitro studies suggested a role in the regulation of local translation at the synapse, thus controlling neuronal plasticity. However, due to the specific structure of miRNA molecules, an in-vivo confirmation of the general role of miRNAs in the control of neuronal plasticity is still pending. For example, their small size and their high level of sequence homology make difficult the analysis of their cellular and sub-cellular localization in-vivo by in-situ hybridization. Moreover, it was found that only 40% of the expressed miRNA molecules in a cell are included in RNA-Induced Silencing Complexes (RISC) and, therefore, involved in inhibitory interactions while the rest is silent. Definitively, the development of new tools is needed to have a better understanding of the cellular function of miRNAs, in particular their role in neuronal plasticity. Here we describe a new technique called in-vivo AGO-APP designed to investigate miRNA expression and function in-vivo. This technique is based on the expression of a small peptide derived from the human RISC-complex protein TNRC6B, called T6B, which binds all known Argonaute (Ago) proteins with high affinity allowing the efficient immunoprecipitation of AGO-bound miRNAs. We have generated two transgenic mouse lines conditionally expressing T6B either ubiquitously in the cell or targeted at the synapse. A comparison of the repertoire of miRNAs immuno-precipitated from mature neurons of both mouse lines will provide us with a list of miRNAs showing a specific activity at the synapse. The physiological role of these miRNAs will be subsequently addressed through gain and loss of function experiments.

Keywords: RNA-induced silencing complexes, TNRC6B, miRNA, argonaute, synapse, neuronal plasticity, neurogenesis

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Authors: K. Akutsu, S. Mori, T. Hanashima

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Fluorescent probes are useful for the selective detection of trace amount of ions and biomolecular imaging in living cells. Various kinds of metal ion-selective fluorescent compounds have been developed, and some compounds have been applied as effective metal ion-selective fluorescent probes. However, because competition between the ligand and water molecules for the metal ion constitutes a major contribution to the stability of a complex in aqueous solution, it is difficult to develop a highly sensitive, selective, and stable fluorescent probe in aqueous solution. The micelles, these are formed in the surfactant aqueous solution, provides a unique hydrophobic nano-environment for stabilizing metal-organic complexes in aqueous solution. Therefore, we focused on the unique properties of micelles to develop a new fluorescence analysis system. We have been developed a fluorescence analysis system for Sr(II) by using a Sr(II) fluorescent sensor, N-(2-hydroxy-3-(1H-benzimidazol-2-yl)-phenyl)-1-aza-18-crown-6-ether (BIC), and studied its complexation behavior with Sr(II) in micellar solution. We revealed that the stability constant of Sr(II)-BIC complex was 10 times higher than that in aqueous solution. In addition, its detection limit value was also improved up to 300 times by this system. However, the mechanisms of these phenomena have remained obscure. In this study, we investigated the structure of Sr(II)-BIC complex in aqueous micellar solution by combining use the extended X-ray absorption fine structure (EXAFS) and neutron reflectivity (NR) method to understand the unique properties of the fluorescence analysis system from the view point of structural chemistry. EXAFS and NR experiments were performed on BL-27B at KEK-PF and on BL17 SHARAKU at J-PARC MLF, respectively. The obtained EXAFS spectra and their fitting results indicated that Sr(II) and BIC formed a Sr(18-crown-6-ether)-like complex in aqueous micellar solution. The EXAFS results also indicated that the hydrophilic head group of surfactant molecule was directly coordinated with Sr(II). In addition, the NR results also indicated that Sr(II)-BIC complex would interact with the surface of micelle molecules. Therefore, we concluded that Sr(II), BIC, and surfactant molecule formed a ternary complexes in aqueous micellar solution, and at least, it is clear that the improvement of the stability constant in micellar solution is attributed to the result of the formation of Sr(BIC)(surfactant) complex.

Keywords: micell, fluorescent probe, neutron reflectivity, EXAFS

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Authors: Shreya Sara Ittycheria, K. C. Sivakumar, Shijulal Nelson Sathi, Priya Srinivas

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hCG, a heterodimer composed of α and β subunits, is a peptide hormone having numerous biological functions. Although hCG is expressed by placenta during pregnancy, ectopic β-hCG secretion is observed in many non-trophoblastic tumors including that of breast. In-vitro and in-vivo studies done in the lab, have proved that BRCA1 defective cancers express β-hCG and when β-hCG is expressed or supplemented, it promotes tumor progression and exhibits resistance to carboplatin and ABT888, in such cancers but not in BRCA1 wild type cancers. In cancer cells, instead of binding to its regular receptor, LH-CGR, β-hCG binds with Transforming Growth Factor Receptor 2 (TGFβRII) and phosphorylates it resulting in faster tumor progression through the Smad signaling pathway. Targeting β-hCG could be a potential therapeutic strategy for managing BRCA1 defective cancers. Here, molecular docking and dynamic simulation studies were done to identify potential small molecule inhibitors against β-hCG as there are currently no such inhibitors reported. The binding sites of TGFβRII on β-hCG were identified from the top 10 predicted complexes from Z Dock. Virtual screening of selected commercially available small molecules from various libraries such as ZINC, NCI and Life Chemicals amounting to a total of 50,025 molecules were done. Four potential small molecule inhibitors were identified, RgcbPs-1, RgcbPs-2, RgcbPs-3 and RgcbPs-4 with binding affinities -60.778 kcal/mol, -45.447 kcal/mol, -65.2268 kcal/mol and -82.040 kcal/mol respectively. Further, 100ns Molecular Dynamics (MD) simulation showed that these molecules form stable complexes with β-hCG. RgcbPs-1 maintains hydrogen bonds with Q54, L52, Q46, C100, G36, C57, C38 residues, RgcbPs-2 maintains hydrogen bonds with A83 residue, RgcbPs-3 maintains hydrogen bonds with C57, Y58, R94, G101 residues and RgcbPs-4 maintains hydrogen bonds with G36, C38, T40, C57, D99, C100, G101 and L104 residues of β-hCG all of which coincide with the TGFβRII binding site on β-hCG. These results show that these two inhibitors could be used either singly or in combination for inhibiting β-hCG from binding to TGFβRII and thereby directly inhibiting the tumorigenesis pathway.

Keywords: β-hCG, breast cancer, dynamic simulations, molecular docking, small molecule inhibitors, virtual screening.

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Authors: Gulcin Yildiz, Hao Feng

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Soybean proteins are the most widely used and researched proteins in the food industry. Due to soy allergies among consumers, however, alternative legume proteins having similar functional properties have been studied in recent years. These alternative proteins are also expected to have a price advantage over soy proteins. One such protein that has shown good potential for food applications is pea protein. Besides the favorable functional properties of pea protein, it also contains fewer anti-nutritional substances than soy protein. However, a comparison of the physicochemical properties of pea protein isolate (PPI)-starch nanocomplexes and soy protein isolate (SPI)-starch nanocomplexes treated by ultrasound has not been well documented. This study was undertaken to investigate the effects of ultrasound treatment on the physicochemical properties of PPI-starch and SPI-starch nanocomplexes. Pea protein isolate (85% pea protein) provided by Roquette (Geneva, IL, USA) and soy protein isolate (SPI, Pro-Fam® 955) obtained from the Archer Daniels Midland Company were adjusted to different pH levels (2-12) and treated with 5 minutes of ultrasonication (100% amplitude) to form complexes with starch. The soluble protein content was determined by the Bradford method using BSA as the standard. The turbidity of the samples was measured using a spectrophotometer (Lambda 1050 UV/VIS/NIR Spectrometer, PerkinElmer, Waltham, MA, USA). The volume-weighted mean diameters (D4, 3) of the soluble proteins were determined by dynamic light scattering (DLS). The emulsifying properties of the proteins were evaluated by the emulsion stability index (ESI) and emulsion activity index (EAI). Both the soy and pea protein isolates showed a U-shaped solubility curve as a function of pH, with a high solubility above the isoelectric point and a low one below it. Increasing the pH from 2 to 12 resulted in increased solubility for both the SPI and PPI-starch complexes. The pea nanocomplexes showed greater solubility than the soy ones. The SPI-starch nanocomplexes showed better emulsifying properties determined by the emulsion stability index (ESI) and emulsion activity index (EAI) due to SPI’s high solubility and high protein content. The PPI had similar or better emulsifying properties at certain pH values than the SPI. The ultrasound treatment significantly decreased the particle sizes of both kinds of nanocomplex. For all pH levels with both proteins, the droplet sizes were found to be lower than 300 nm. The present study clearly demonstrated that applying ultrasonication under different pH conditions significantly improved the solubility and emulsify¬ing properties of the SPI and PPI. The PPI exhibited better solubility and emulsifying properties than the SPI at certain pH levels

Keywords: emulsifying properties, pea protein isolate, soy protein isolate, ultrasonication

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Authors: Khodzhaberdi Allaberdiev

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Substituted phenols are widely used for the synthesis of advanced polycondensation polymers. In terms of the structure regularity and practical value of obtained polymers are of special interest the p-substituted phenols. The lanthanide induced shifts (LIS) of the aromatic ring and the OH protons by addition Eu(fod)3 to various p-substituted phenols in CDCL3 solvent were measured Nuclear Magnetic Resonance spectroscopy. A linear relationship has been observed between the LIS of protons (∆=δcomplex –δsubstrate) and Eu(fod)3/substrate molar ratios. The LIS protons of the investigated phenols decreases in the following order: ОН > ortho > meta. The LIS of these protons also depends on both steric and electronic effects of p-substituents. The effect on the LIS of protons steric hindrance of substituents by way of example p-substituted alkyl phenols was studied. Alkyl phenols exhibit pronounced europium- induced shifts, their sensitivity increasing in the order: CH3 > C2H5 > sym-C5H11 > tert-C5H11 > tert-C4H9, i.e. in parallel with decreasing steric hindrance. The influence steric hindrance p-substituents of phenols on the LIS of protons in sequence following decreases: OH> meta >ortho. Contrary to the expectations, it is found that the LIS of the ortho protons an excellent linear correlation with meta-substituent constants, σm for 14 p-substituted phenols: ∆H2, 6=8.165-9.896 σm (r2=0,999). Moreover, a linear correlation between the LIS of the ortho protons and ionization constants, РКa of p-substituted phenols has been revealed. Similarly, the linear relationships for the LIS of the meta and the OH protons were obtained. Use the LIS of the phenolic hydroxyl groups for linear relationships is necessary with care, because of the signal broadening of the OH protons. New constants may be determinate with unusual case by this approach.

Keywords: novel correlations, NMR spectroscopy, phenols, shift reagent

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Authors: Kalina Alina Aidarovna, Khayrullina Yulia Sergeevna

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The question of forming quality housing and living environment remains a vexed problem in the current situation of high-rise apartment building in big cities of Russia. At this start up stage of the modern so-called "mass housing" market it needs to identify key quality characteristics on a different scale from apartments to the district. This paper describes the methodology of qualitative assessment of modern mass housing construction, made on the basis of the ITMO university in cooperation with the institute of spatial planning "Urbanika," based on the case study of St. Petersburg’s residential mass housing built in 2011-2014. The methodology of the study of housing and living environment goes back to the native and foreign urbanists of 60s - 80s, such Jane Jacobs, Jan Gehl, Oscar Newman, Krasheninnikov, as well as Sommer, Stools, Kohnen and Sherrod, Krasilnikova, Sychev, Zhdanov, Tinyaeva considering spatial features of living environment in a wide range of its characteristics (environmental control, territorial and personalization, privacy, etc.). Assessment is carrying out on the proposed system of criteria developed for each residential environment scale-district, quarter, courtyard, building surrounding grounds, houses, and flats. Thus the objects of study are planning unit of residential development areas (residential area, neighborhood, quarter) residential units areas (living artist, a house), and households (apartments) consisting of residential units. As a product of identified methodology, after the results of case studies of more than 700 residential complexes in St. Petersburg, we intend the creation of affordable online resource that would allow conducting a detailed qualitative evaluation or comparative characteristics of residential complexes for all participants of the construction market-developers, designers, realtors and buyers. Thereby the main objective of the rating may be achieved to improve knowledge, requirements, and demand for quality housing and living environment among the major stakeholders of the construction market.

Keywords: methodology of living environment, qualitative assessment of mass housing, scale-district, vexed problem

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Authors: Mohamad Saab, Florent Real, Francois Virot, Laurent Cantrel, Valerie Vallet

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All spent nuclear fuel reprocessing plants use the PUREX process (Plutonium Uranium Refining by Extraction), which is a liquid-liquid extraction method. The organic extracting solvent is a mixture of tri-n-butyl phosphate (TBP) and hydrocarbon solvent such as hydrogenated tetra-propylene (TPH). By chemical complexation, uranium and plutonium (from spent fuel dissolved in nitric acid solution), are separated from fission products and minor actinides. During a normal extraction operation, uranium is extracted in the organic phase as the UO₂(NO₃)₂(TBP)₂ complex. The TBP solvent can form an explosive mixture called red oil when it comes in contact with nitric acid. The formation of this unstable organic phase originates from the reaction between TBP and its degradation products on the one hand, and nitric acid, its derivatives and heavy metal nitrate complexes on the other hand. The decomposition of the red oil can lead to violent explosive thermal runaway. These hazards are at the origin of several accidents such as the two in the United States in 1953 and 1975 (Savannah River) and, more recently, the one in Russia in 1993 (Tomsk). This raises the question of the exothermicity of reactions that involve TBP and all other degradation products, and calls for a better knowledge of the underlying chemical phenomena. A simulation tool (Alambic) is currently being developed at IRSN that integrates thermal and kinetic functions related to the deterioration of uranyl nitrates in organic and aqueous phases, but not of the n-butyl phosphate. To include them in the modeling scheme, there is an urgent need to obtain the thermodynamic and kinetic functions governing the deterioration processes in liquid phase. However, little is known about the thermodynamic properties, like standard enthalpies of formation, of the n-butyl phosphate molecules and of the UO₂(NO₃)₂(TBP)₂ UO₂(NO₃)₂(HDBP)(TBP) and UO₂(NO₃)₂(HDBP)₂ complexes. In this work, we propose to estimate the thermodynamic properties with Quantum Methods (QM). Thus, in the first part of our project, we focused on the mono, di, and tri-butyl complexes. Quantum chemical calculations have been performed to study several reactions leading to the formation of mono-(H₂MBP), di-(HDBP), and TBP in gas and liquid phases. In the gas phase, the optimal structures of all species were optimized using the B3LYP density functional. Triple-ζ def2-TZVP basis sets were used for all atoms. All geometries were optimized in the gas-phase, and the corresponding harmonic frequencies were used without scaling to compute the vibrational partition functions at 298.15 K and 0.1 Mpa. Accurate single point energies were calculated using the efficient localized LCCSD(T) method to the complete basis set limit. Whenever species in the liquid phase are considered, solvent effects are included with the COSMO-RS continuum model. The standard enthalpies of formation of TBP, HDBP, and H2MBP are finally predicted with an uncertainty of about 15 kJ mol⁻¹. In the second part of this project, we have investigated the fundamental properties of three organic species that mostly contribute to the thermal runaway: UO₂(NO₃)₂(TBP)₂, UO₂(NO₃)₂(HDBP)(TBP), and UO₂(NO₃)₂(HDBP)₂ using the same quantum chemical methods that were used for TBP and its derivatives in both the gas and the liquid phase. We will discuss the structures and thermodynamic properties of all these species.

Keywords: PUREX process, red oils, quantum chemical methods, hydrolysis

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Authors: Ved Vrat Verma, Rani Gupta, Manisha Goel

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γ-glutamyltranspeptidase (GGT: EC 2.3.2.2) is an N-terminal nucleophile hydrolase conserved in all three domains of life. GGT plays a key role in glutathione metabolism where it catalyzes the breakage of the γ-glutamyl bonds and transfer of γ-glutamyl group to water (hydrolytic activity) or amino acids or short peptides (transpeptidase activity). GGTs from bacteria, archaea, and eukaryotes (human, rat and mouse) are homologous proteins sharing >50% sequence similarity and conserved four layered αββα sandwich like three dimensional structural fold. These proteins though similar in their structure to each other, are quite diverse in their enzyme activity: some GGTs are better at hydrolysis reactions but poor in transpeptidase activity, whereas many others may show opposite behaviour. GGT is known to be involved in various diseases like asthma, parkinson, arthritis, and gastric cancer. Its inhibition prior to chemotherapy treatments has been shown to sensitize tumours to the treatment. Microbial GGT is known to be a virulence factor too, important for the colonization of bacteria in host. However, all known inhibitors (mimics of its native substrate, glutamate) are highly toxic because they interfere with other enzyme pathways. However, a few successful efforts have been reported previously in designing species specific inhibitors. We aim to leverage the diversity seen in GGT family (pathogen vs. eukaryotes) for designing specific inhibitors. Thus, in the present study, we have used DIVERGE software to identify sites in GGT proteins, which are crucial for the functional and structural divergence of these proteins. Since, type II divergence sites vary in clade specific manner, so type II divergent sites were our focus of interest throughout the study. Type II divergent sites were identified for pathogen vs. eukaryotes clusters and sites were marked on clade specific representative structures HpGGT (2QM6) and HmGGT (4ZCG) of pathogen and eukaryotes clade respectively. The crucial divergent sites within 15 A radii of the binding cavity were highlighted, and in-silico mutations were performed on these sites to delineate the role of these sites on the mechanism of catalysis and protein folding. Further, the amino acid network (AAN) analysis was also performed by Cytoscape to delineate assortative mixing for cavity divergent sites which could strengthen our hypothesis. Additionally, molecular dynamics simulations were performed for wild complexes and mutant complexes close to physiological conditions (pH 7.0, 0.1 M ionic strength and 1 atm pressure) and the role of putative divergence sites and structural integrities of the homologous proteins have been analysed. The dynamics data were scrutinized in terms of RMSD, RMSF, non-native H-bonds and salt bridges. The RMSD, RMSF fluctuations of proteins complexes are compared, and the changes at protein ligand binding sites were highlighted. The outcomes of our study highlighted some crucial divergent sites which could be used for novel inhibitors designing in a species-specific manner. Since, for drug development, it is challenging to design novel drug by targeting similar protein which exists in eukaryotes, so this study could set up an initial platform to overcome this challenge and help to deduce the more effective targets for novel drug discovery.

Keywords: γ-glutamyltranspeptidase, divergence, species-specific, drug design

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Authors: D. Artamonov, A. Tsibulnikova, I. Samusev, V. Bryukhanov, A. Kozhevnikov

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The synthesis and luminescent properties of Yb₂O₃, Nd₂O₃@Bi₂O₃ complex with upconversion generation are discussed in this work. The obtained samples were measured in the visible region of the spectrum under excitation with a wavelength of 980 nm. The studies showed that the obtained complexes have a high degree of stability and intense luminescence in the wavelength range of 400-750 nm. Consideration of the time dependence of the intensity of the upconversion luminescence allowed us to conclude that the enhancement of the intensity occurs in the time interval from 5 to 30 min, followed by the appearance of a stationary mode.

Keywords: lasers, luminescence, upconversion photonics, rare earth metals

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Authors: Andreea Cârâc, Elena Morosan, Ana Corina Ionita, Rica Bosencu, Geta Carac

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Lanthanum carbonate exhibits a considerable ability to bind phosphate and the substitution of Ca2+ ions by divalent or trivalent lanthanide metal ions attracted attention during the past few years. Although Lanthanum carbonate has not been approved by the FDA for treatment of hyperphosphatemia, we prospectively evaluated the efficacy of the combination of Calcium hydroxyapatite and Lanthanum carbonate for the treatment of hyperphosphatemia on mice. Calcium hydroxyapatite commonly referred as CHAp is a bioceramic material and is one of the most important implantable materials due to its biocompatibility and osteoconductivity. We prepared calcium hydroxyapatite and lanthanum carbonate. CHAp was prepared by co-precipitation method using Ca(OH)2, H3PO4, NH4OH with calcination at 1200ºC. Lanthanum carbonate was prepared by chemical method using NaHCO3 and LaCl3 at low pH environment , ph below 4.0 The confirmation of both substances structures was made using XRD characterization, FTIR spectra and SEM /EDX analysis. The study group included 20 subjects-mice divided into four groups according to the administered substance: lanthanum carbonate (group A), lanthanum carbonate + CHAp (group B), CHAp (group C) and salt water (group D). The results indicate a phosphate decrease when subjects (mice) were treated with CHAp and lanthanum carbonate (0.5 % CMC), in a single dose of 1500 mg/kg. Serum phosphate concentration decreased [from 4.5 ± 0.8 mg/dL) to 4.05 ± 0.2 mg/dL), P < 0.01] in group A and to 3.6 ± 0.2 mg/dL] only after the 24 hours of combination therapy. The combination of CHAp and lanthanum carbonate is a suitable regimen for hyperphosphatemia treatment subjects because it avoids both the hypercalcemia of CaCO3 and the adverse effects of CHAp. The ability of CHAp to decrease the serum phosphate concentration is 1/3 that of lanthanum carbonate.

Keywords: calcium hydroxyapatite, hyperphosphatemia, lanthanum carbonate, phosphate, structures

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Authors: A. Bara, D. Barkat

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Liquid-liquid extraction is one of the most useful techniques for selective removal and recovery of metal ions from aqueous solutions, applied in purification processes in numerous chemical and metallurgical industries. In this work, The liquid-liquid extraction of cobalt (II) and copper (II) from aqueous solution by capric acid (HL) in chloroform at 25°C has been studied. Our interest in this paper is to study the effect of concentration of capric acid on the extraction of Co(II) and Cu(II) to see the complexes could be formed in the organic phase using various concentration of capric acid. The extraction of cobalt (II) and copper (II) is extracted as the complex CoL2 (HL )2, CuL2 (HL)2.

Keywords: capric acid, Cobalt(II), copper(II), liquid-liquid extraction

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Authors: Iwona Misztalewska-Turkowicz, Agnieszka Z. Wilczewska, Karolina H. Markiewicz

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Carbenes - species which possess neutral carbon atom with two shared and two unshared valence electrons, are known for their high reactivity and instability. Nevertheless, it is also known, that some carbenes i.e. N-heterocyclic carbenes (NHCs), can form stable crystals. The usability of NHCs in organic synthesis was studied. Due to their exceptional properties (high nucleophilicity) NHCs are commonly used as organocatalysts and also as ligands in transition metal complexes. NHC ligands possess better electron-donating properties than phosphines. Moreover, they exhibit lower toxicity. Due to these features, phosphines are frequently replaced by NHC ligands. In this research is discussed the synthesis of five-membered NHCs which are mainly obtained by deprotonation of azolium salts, e.g., imidazolium or imidazolinium salts. Some of them are immobilized on a solid support what leads to formation of heterogeneous, recyclable catalysts. Magnetic nanoparticles (MNPs) are often used as a solid support for catalysts. MNPs can be easily separated from the reaction mixture using an external magnetic field. Due to their low size and high surface to volume ratio, they are a good choice for immobilization of catalysts. Herein is presented synthesis of N-heterocyclic carbene copper complexes directly on the surface of magnetic nanoparticles. Formation of four different catalysts is discussed. They vary in copper oxidation state (Cu(I) and Cu(II)) and structure of NHC ligand. Catalysts were tested in Huisgen reaction, a type of copper catalyzed azide-alkyne cycloaddition (CuAAC) reaction. Huisgen reaction represents one of the few universal and highly efficient reactions in which 1,2,3-triazoles can be obtained. The catalytic activity of all synthesized catalysts was compared with activity of commercially available ones. Different reaction conditions (solvent, temperature, the addition of reductant) and reusability of the obtained catalysts were investigated and are discussed. The project was financially supported by National Science Centre, Poland, grant no. 2016/21/N/ST5/01316. Analyses were performed in Centre of Synthesis and Analyses BioNanoTechno of University of Bialystok. The equipment in the Centre of Synthesis and Analysis BioNanoTechno of University of Bialystok was funded by EU, as a part of the Operational Program Development of Eastern Poland 2007-2013, project: POPW.01.03.00-20-034/09-00 and POPW.01.03.00-20-004/11.

Keywords: N-heterocyclic carbenes, click reaction, magnetic nanoparticles, copper catalysts

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Authors: Tomilola J. Ajayi

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A category of nanovalves system containing the α-cyclodextrin (α-CD) ring on a stalk tethered to the pores of mesoporous silica nanoparticles (MSN) is theoretically and computationally modelled. This functions to control opening and blocking of the MSN pores for efficient targeted drug release system. Modeling of the nanovalves is based on the interaction between α-CD and the stalk (p-anisidine) in relation to pH variation. Conformational analysis was carried out prior to the formation of the inclusion complex, to find the global minimum of both neutral and protonated stalk. B3LYP/6-311G**(d, p) basis set was employed to attain all theoretically possible conformers of the stalk. Six conformers were taken into considerations, and the dihedral angle (θ) around the reference atom (N17) of the p-anisidine stalk was scanned from 0° to 360° at 5° intervals. The most stable conformer was obtained at a dihedral angle of 85.3° and was fully optimized at B3LYP/6-311G**(d, p) level of theory. The most stable conformer obtained from conformational analysis was used as the starting structure to create the inclusion complexes. 9 complexes were formed by moving the neutral guest into the α-CD cavity along the Z-axis in 1 Å stepwise while keeping the distance between dummy atom and OMe oxygen atom on the stalk restricted. The dummy atom and the carbon atoms on α-CD structure were equally restricted for orientation A (see Scheme 1). The generated structures at each step were optimized with B3LYP/6-311G**(d, p) methods to determine their energy minima. Protonation of the nitrogen atom on the stalk occurs at acidic pH, leading to unsatisfactory host-guest interaction in the nanogate; hence there is dethreading. High required interaction energy and conformational change are theoretically established to drive the release of α-CD at a certain pH. The release was found to occur between pH 5-7 which agreed with reported experimental results. In this study, we applied the theoretical model for the prediction of the experimentally observed pH-responsive nanovalves which enables blocking, and opening of mesoporous silica nanoparticles pores for targeted drug release system. Our results show that two major factors are responsible for the cargo release at acidic pH. The higher interaction energy needed for the complex/nanovalve formation to exist after protonation as well as conformational change upon protonation are driving the release due to slight pH change from 5 to 7.

Keywords: nanovalves, nanogate, mesoporous silica nanoparticles, cargo

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Authors: Sender Dovchin

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Moving beyond two main frameworks of interlingual and intralingual discrimination, this paper will address the understanding of translingual discrimination. This concept refers to discrimination based on how one uses certain languages, linguistic and communicative repertoires, which are (il)legitimised by the interactants. Translingual discrimination contributes intensity to transnational migrations processes, where migrants with transitional backgrounds seem to illustrate two main characteristics of marginalizations – “name discrimination” and “accentism”. The lifelong accumulation of these characteristics of translingual discrimination may cause negative emotionality, such as translingual inferiority complexes, to its victims. As a result, these transnational migrants seem to adopt varied coping strategies such as CV-whitening and accent purifications while probing for translingual safe spaces. The presentation concludes with the socio-cultural and pedagogical implications of translingual discrimination in relation to the language usage of transnational migrants.

Keywords: accentism, discrimination, migrants, translingualism

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Authors: Mohamed Nasraoui

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Spatial ore distribution, ore heterogeneity and their links with geological processes involved in Niobium concentration are all factors for consideration when bridging field observations to extraction scheme. Indeed, mineralogy changes of Nb-hosting phases, their textural relationships with hydrothermal or secondary minerals, play a key control over mineral processing. This study based both on filed work and ore characterization presents data from several Nb-deposits related to carbonatite complexes. The results obtained by a wide range of analytical techniques, including, XRD, XRF, ICP-MS, SEM, Microprobe, Spectro-CL, FTIR-DTA and Mössbauer spectroscopy, demonstrate how geometallurgical assessment, at all stage of mine development, can greatly assist in the design of a suitable extraction flowsheet and data reconciliation.

Keywords: carbonatites, Nb-geometallurgy, Nb-mineralogy, mineral processing.

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Authors: J. Mrazek, R. Skala, S. Bysakh, Ivan Kasik

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Lanthanide-doped yttrium titanium oxides, which crystallize in a pyrochlore structure with general formula (RExY1-x)2Ti2O7 (RE=rare earth element), have been extensively investigated in recent years for their interesting physical and chemical properties. Despite that the pure pyrochlore structure does not present luminescence ability, the presence of yttrium ions in the pyrochlore structure significantly improves the luminescence properties of the RE. Moreover, the luminescence properties of pyrochlores strongly depend on the size of formed nanocrystals. In this contribution, we present a versatile sol-gel synthesis of nanocrystalline EuYTi2O7pyrochlore. The nanocrystalline powders and thin films were prepared by the condensation of titanium(IV)butoxide with europium(III) chloride followed by the calcination. The introduced method leads to the formation of the highly-homogenous nanocrystalline EuYTi2O7 with tailored grain size ranging from 20 nm to 200 nm. The morphology and the structure of the formed nanocrystals are linked to the luminescence properties of Eu3+ ions incorporated into the pyrochlore lattice. The results of XRD and HRTEM analysis show that the Eu3+ and Y3+ ions are regularly distributed inside the lattice. The lifetime of Eu3+ ions in calcinated powders is regularly decreasing from 140 us to 68 us and the refractive index of prepared thin films regularly increases from 2.0 to 2.45 according to the calcination temperature. The shape of the luminescence spectra and the decrease of the lifetime correspond with the crystallinity of prepared powders. The results present fundamental information about the effect of the size of the nanocrystals to their luminescence properties. The promising application of prepared nanocrystals in the field of lasers and planar optical amplifiers is widely discussed in the contribution.

Keywords: europium, luminescence, nanocrystals, sol-gel

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Authors: Neha Verma, Manik Rakhra

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Statement of the Problem: Nowadays, a tremendous increase in population and advanced industrialization augment the problems related to air and water pollutions. Growing industries promoting environmental danger, which is an alarming threat to the ecosystem. For safeguard, the environment, detection of perilous gases and release of colored wastewater is required for eutrophication pollution. Researchers around the globe are trying their best efforts to save the environment. For this remediation advanced oxidation process is used for potential applications. ZnO is an important semiconductor photocatalyst with high photocatalytic and gas sensing activities. For efficient photocatalytic and gas sensing properties, it is necessary to prepare a doped/co-doped ZnO compound to decrease the electron-hole recombination rates. However, lanthanide doped and co-doped metal oxide is seldom studied for photocatalytic and gas sensing applications. The purpose of this study is to describe the best photocatalyst for the photodegradation of dyes and gas sensing properties. Methodology & Theoretical Orientation: Economical framework has to be used for the synthesis of ZnO. In the depth literature survey, a simple combustion method is utilized for gas sensing and photocatalytic activities. Findings: Rare earth doped and co-doped ZnO nanoparticles were the best photocatalysts for photodegradation of organic dyes and different gas sensing applications by varying various factors such as pH, aging time, and different concentrations of doping and codoping metals in ZnO. Complete degradation of dye was observed only in min. Gas sensing nanodevice showed a better response and quick recovery time for doped/co-doped ZnO. Conclusion & Significance: In order to prevent air and water pollution, well crystalline ZnO nanoparticles were synthesized by rapid and economic method, which is used as photocatalyst for photodegradation of organic dyes and gas sensing applications to sense the release of hazardous gases from the environment.

Keywords: ZnO, photocatalyst, photodegradation of dye, gas sensor

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Authors: Diana M. Torres, Anngie K. Hernandez, Andrea Villareal, Magda R. Gomez, Sadao Kobayashi

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Colombian Garlic crops exhibited mild mosaic, yellow stripes, and deformation. This group of symptoms suggested a viral infection. Several viruses belonging to the genera Potyvirus, Carlavirus and Allexivirus are known to infect garlic and lower their yield worldwide, but in Colombia, there are no studies of viral infections in this crop, only leek yellow stripe virus (LYSV) has been reported to our best knowledge. In Colombia, there are no management strategies for viral diseases in garlic because of the lack of information about viral infections on this crop, which is reflected in (i) high prevalence of viral related symptoms in garlic fields and (ii) high dispersal rate. For these reasons, the purpose of the present study was to evaluate the viral status of garlic in Colombia, which can represent a major threat on garlic yield and quality for this country 55 symptomatic leaf samples were collected for virus detection by RT-PCR and mechanical inoculation. Total RNA isolated from infected samples were subjected to RT-PCR with primers 1-OYDV-G/2-OYDV-G for Onion yellow dwarf virus (OYDV) (expected size 774pb), 1LYSV/2LYSV for LYSV (expected size 1000pb), SLV 7044/SLV 8004 for Shallot latent virus (SLV) (expected size 960pb), GCL-N30/GCL-C40 for Garlic common latent virus (GCLV) (expected size 481pb) and EF1F/EF1R for internal control (expected size 358pb). GCLV, SLV, and LYSV were detected in infected samples; in 95.6% of the analyzed samples was detected at least one of the viruses. GCLV and SLV were detected in single infection with low prevalence (9.3% and 7.4%, respectively). Garlic generally becomes coinfected with several types of viruses. Four viral complexes were identified: three double infection (64% of analyzed samples) and one triple infection (15%). The most frequent viral complex was SLV + GCLV infecting 48.1% of the samples. The other double complexes identified had a prevalence of 7% (GCLV + LYSV and SLV + LYSV) and 5.6% of the samples were free from these viruses. Mechanical transmission experiments were set up using leaf tissues of collected samples from infected fields, different test plants were assessed to know the host range, but it was restricted to C. quinoa, confirming the presence of detected viruses which have limited host range and were detected in C. quinoa by RT-PCR. The results of molecular and biological tests confirm the presence of SLV, LYSV, and GCLV; this is the first report of SLV and LYSV in garlic plants in Colombia, which can represent a serious threat for this crop in this country.

Keywords: SLV, GCLV, LYSV, leek yellow stripe virus, Allium sativum

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Authors: Yalçın Kılıç, İbrahim Kani

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In recent years, interest in the synthesis of coordination compounds has greatly increased due to various application areas (such as catalysis, gas storage, luminescence). Dicarboxylic acids are often used in the synthesis of metal complexes. Bis-thiosalicylate derivative ligands contribute to the synthesis of structures of crystal engineering interest, as they can have both rigid and flexible properties. In addition, these ligands have great potential in terms of catalytic applications with the sulfur and oxygen donor atoms in their structures. In this study, we synthesized a Cu(II) complex [Cu(tsaxyl)(phen)2]•CH3OH (where tsaxyl = 2,2'-(1,2-phylenebis(methylene))bis(sulfanedyl)dibenzoate, phen = 1,10-phenantroline) and characterized through X-ray crystallography. The catalytic activities of Cu(II) complex on oxidation of ethylbenzene, cyclohexane, diphenylmethane, p-xylene were performed in acetonitrile with t-BuOOH as the source of oxygen.

Keywords: complex, crystallography, catalysis, oxidation

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Authors: Arzu Javadova

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The complex of sedimentary deposits that make up the West Turkmen Basin is almost completely hidden under the Quaternary formations. The most ancient deposits emerging on the surface in some places are the deposits of the Red Color Suite of the Pliocene. Miocene deposits are exposed only at the Western end of the Kopet Dag. The main object of stratigraphic, including micropaleontological studies, were the deposits of the Quaternary and Pliocene forming marine and coastal structures. The identified stratigraphic units have certain characteristic Ostracod complexes. The fauna of the Ostracod acquires special significance in the stratification of Neogene and Quaternary deposits. Ostracods of the Neogene, Pliocene and Quaternary deposits of the West Turkmen depression are represented by a large part of the species common in the corresponding deposits of Azerbaijan and Iran.

Keywords: neogene, quaternary, turkmenistan, south caspian basin, ostracoda, foraminifera, biostratigraphy, paleontology

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Authors: Indra Bahadur Bhandari, Narayan Panthi, Ishwar Koirala, Devendra Adhikari

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We have used a theoretical model based on the assumption of compound formation in binary alloys to study the thermodynamic, microscopic, and surface properties of Bi-Pb and In-Pb liquid alloys. A review of the phase diagrams for these alloys shows that one of the stable complexes for Bi-Pb liquid alloy is BiPb3; also, that InPb is a stable phase in liquid In-Pb alloys. Using the same interaction parameters that are fitted for the free energy of mixing, we have been able to compute the bulk and thermodynamic properties of the alloys. From our observations, we are able to show that the Bi-Pb liquid alloy exhibits compound formation over the whole concentration range and the In-Pb alloys undergo phase separation. With regards to surface properties, Pb segregates more to the surface in In-Pb alloys than in Bi-Pb alloys. The viscosity isotherms have a positive deviation from ideality for both Bi-Pb and In-Pb alloys.

Keywords: asymmetry, Bi-Pb, deviation, In-Pb, interaction parameters

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Authors: Otuwose E. Agyeno, Adeniyi A. Jayeola, Bashir A. Ajala

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P. esculentus is indigenous to Nigeria yet no wild relation has been encountered or reported. This has made it difficult to establish proper lineages between the varieties and landraces under cultivation. The present work is the first to determine the apormophy of 135 morphoanatomical characters in organs of 46 accessions drawn from 23 populations of this species based on dicta. The character states were coded in accession x character-state matrices and only 83 were informative and utilised for neighbour joining clustering based on euclidean values, and heuristic search in parsimony analysis using PAST ver. 3.15 software. Compatibility and evolutionary trends between accessions were then explored from values and diagrams produced. The low consistency indices (CI) recorded support monophyly and low homoplasy in this taxon. Agglomerative schedules based on character type and source data sets divided the accessions into mainly 3 clades, each of complexes of accessions. Solenostemon rotundifolius (Poir) J.K Morton was the outgroup (OG) used, and it occurred within the largest clades except when the characters were combined in a data set. The OG showed better compatibility with accessions of populations of landrace Isci, and varieties Riyum and Long’at. Otherwise, its aerial parts are more consistent with those of accessions of variety Bebot. The highly polytomous clades produced due to anatomical data set may be an indication of how stable such characters are in this species. Strict consensus trees with more than 60 nodes outputted showed that the basal nodes were strongly supported by 3 to 17 characters across the data sets, suggesting that populations of this species are more alike. The OG was clearly the first diverging lineage and closely related to accessions of landrace Gwe and variety Bebot morphologically, but different from them anatomically. It was also distantly related to landrace Fina and variety Long’at in terms of root, stem and leaf structural attributes. There were at least 5 other clades with each comprising of complexes of accessions from different localities and terrains within the study area. Spherical stem in cross section, size of vascular bundles at the stem corners as well as the alternate and whorl phyllotaxy are attributes which may have facilitated each other’s evolution in all accessions of the landrace Gwe, and they may be innovative since such states are not characteristic of the larger Lamiaceae, and Plectranthus L’Her in particular. In conclusion, this study has provided valuable information about infraspecific diversity in this taxon. It supports recognition of the varietal statuses accorded to populations of P. esculentus, as well as the hypothesis that the wild gene might have been distributed on the Jos Plateau. However, molecular characterisation of accessions of populations of this species would resolve this problem better.

Keywords: clustering, lineage, morphoanatomical characters, Nigeria, phylogenetics, Plectranthus esculentus, population

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Authors: Darshna Sharma, Suban K. Sahoo

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The detection of intracellular fluoride in human cancer cell HeLa was achieved by chemosensors derived from vitamin B6 cofactors using fluorescence imaging technique. These sensors were first synthesized by condensation of pyridoxal/pyridoxal phosphate with 2-amino(thio)phenol. The anion recognition ability was explored by experimental (UV-VIS, fluorescence and 1H NMR) and theoretical DFT [(B3LYP/6-31G(d,p)] methods in DMSO and mixed DMSO-H2O system. All the developed sensors showed both naked-eye detectable color change and remarkable fluorescence enhancement in the presence of F- and AcO-. The anion recognition was occurred through the formation of hydrogen bonded complexes between these anions and sensor, followed by the partial deprotonation of sensor. The detection limit of these sensors were down to micro(nano) molar level of F- and AcO-.

Keywords: chemosensors, fluoride, acetate, turn-on, live cells imaging, DFT

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Authors: S. A. Kondratyev, O. I. Ibragimova

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The authors discuss the collecting abilities of desorbable species (DS) of saturated fatty acids. The DS species of the reagent are understood as species capable of moving from the surface of the mineral particle to the bubble at the moment of the rupture of the interlayer of liquid separating these objects of interaction. DS species of carboxylic acids (molecules and ionic-molecular complexes) have the ability to spread over the surface of the bubble. The rate of their spreading at pH 7 and 10 over the water surface is determined. The collectibility criterion of saturated fatty acids is proposed. The values of forces exerted by the spreading DS species of reagents on liquid in the interlayer and the liquid flow rate from the interlayer are determined.

Keywords: criterion of action of physically adsorbed reagent, flotation, saturated fatty acids, surface pressure

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Authors: Y. A. R. Oliveira, M. A. Couto dos Santos, N. B. C. Júnior, S. J. L. Ribeiro, L. D. Carlos

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The Eu(TTA)3(H2O)2 complex (TTA = thenoyltrifluoroacetone) pure (EuTTA) and incorporated in an organicinorganic hybrid material (EuTTA-hyb) are revisited, this time from the crystal field parameters (CFP) and Judd-Ofelt intensity parameters (Ωλ) point of view. A detailed analysis of the emission spectra revealed that the EuTTA phase still remains in the hybrid phase. Sparkle Model calculations of the EuTTA ground state geometry have been performed and satisfactorily compared to the X-ray structure. The observed weaker crystal field strength of the phase generated by the incorporation is promptly interpreted through the existing EXAFS results of the EuTTA-hyb structure. Satisfactory predictions of the CFP, of the 7F1 level splitting and of the Ωλ in all cases were obtained by using the charge factors and polarizabilities as degrees of freedom of non-parametric models.

Keywords: crystal field parameters, europium complexes, Judd-Ofelt intensity parameters

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Authors: Nurul Huda Baharuddin, Nik Meriam Nik Sulaiman, Mohammed Kheireddine Aroua

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The effects of pH, polymer concentration, and metal ions feed concentration for four selected heavy metals Zn (II), Pb (II), Cr (III) and Cr (VI) were tested by using Polymer Enhanced Ultrafiltration (PEUF). An alternative biopolymer namely unmodified starch is proposed as a binding reagent in consequences, as compared to commonly used water-soluble polymers namely polyethylene glycol (PEG) and polyethyleneimine (PEI) in the removal of selected four heavy metal ions. The speciation species profiles of four selected complexes ions namely Zn (II), Pb (II), Cr (III) and Cr (VI) and the present of hydroxides ions (OH-) in variously charged ions were investigated by available software at certain pH range. In corresponds to identify the potential of complexation behavior between metal ion-polymers, potentiometric titration studies were obtained at first before carried out experimental works. Experimental works were done using ultrafiltration systems obtained by laboratory ultrafiltration bench scale equipped with 10 kDa polysulfone hollow fiber membrane. Throughout the laboratory works, the rejection coefficient and permeate flux were found to be significantly affected by the main operating parameter, namely the effects of pH, polymer composition and metal ions concentrations. The interaction of complexation between two binding polymers namely unmodified starch and PEG were occurred due to physical attraction of metal ions to the polymer on the molecular surface with high possibility of chemical occurrence. However, these selected metal ions are mainly complexes by polymer functional groups whenever there is interaction with PEI polymer. For study of single metal ions solutions, Zn (II) ions' rejections approaching over 90% were obtained at pH 7 for each tested polymer. This behavior was similar to Pb (II), Cr (III) and Cr (VI); where the rejections were obtained at lower acidic pH and increased at neutral pH of 7. Different behavior was found by Cr (VI) ions where a high rejection was only achieved at acidic pH region with PEI. Polymer concentration and metal ions concentration are found to have a significant effect on rejections. For mixed metal ion solutions, the behavior of metal ion rejections was similar to single metal ion solutions for investigation on the effects of pH. Rejection values were high at pH 7 for Zn (II) pH 7 for Zn (II) and Cr (III) ions, corresponding to higher rejections with unmodified starch. Pb (II) ions obtained high rejections when tested with PEG whenever carried out in mixed metal ion solutions. High Cr (VI) ions' rejection was found with PEI in single and mixed metal ions solutions at neutral pH range. The influence of starch’s granule structure towards the rejections of these four selected metal ions is found to be attracted in a non-ionic manner. No significant effects on permeate flux were obtained when tested at different pH ranges, polymer concentrations and metal ions feed either by single or mixtures metal ions solutions. Canizares Model was employed as the theoretical model to predict permeate flux and metal ions retention on the study of heavy metal ions removal.

Keywords: polyethyleneimine, polyethylene glycol, polymer-enhanced ultrafiltration, unmodified starch

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Authors: Xiaoyun Hui, Fiona Gentle, Clemens Engelke, Margaret C. Graham

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Although past work has shown that phosphorus (P), an important nutrient, may form complexes with aqueous humic substances (HS), the principal component of natural organic matter, the nature of such interactions is poorly understood. Humic complexation may not only enhance P concentrations but it may change its bioavailability within such waters and, in addition, influence its transport within catchment settings. This project is examining the relationships and associations of P, HS, and iron (Fe) in Loch Meadie, Sutherland, North Scotland, a mesohumic freshwater loch which has been assessed as reference condition with respect to P. The aim is to identify characteristic spectroscopic parameters which can enhance the performance of the model currently used to predict reference condition TP levels for highly-coloured Scottish lochs under the Water Framework Directive. In addition to Loch Meadie, samples from other reference condition lochs in north Scotland and Shetland were analysed. By including different types of reference condition lochs (clear water, mesohumic and polyhumic water) this allowed the relationship between total phosphorus (TP) and HS to be more fully explored. The pH, [TP], [Fe], UV/Vis absorbance/spectra, [TOC] and [DOC] for loch water samples have been obtained using accredited methods. Loch waters were neutral to slightly acidic/alkaline (pH 6-8). [TP] in loch waters were lower than 50 µg L-1, and in Loch Meadie waters were typically <10 µg L-1. [Fe] in loch waters were mainly <0.6 mg L-1, but for some loch water samples, [Fe] were in the range 1.0-1.8 mg L-1and there was a positive correlation with [TOC] (r2=0.61). Lochs were classified as clear water, mesohumic or polyhumic based on water colour. The range of colour values of sampled lochs in each category were 0.2–0.3, 0.2–0.5 and 0.5–0.8 a.u. (10 mm pathlength), respectively. There was also a strong positive correlation between [DOC] and water colour (R2=0.84). The UV/Vis spectra (200-700 nm) for water samples were featureless with only a slight “shoulder” observed in the 270–290 nm region. Ultrafiltration was then used to separate colloidal and truly dissolved components from the loch waters and, since it contained the majority of aqueous P and Fe, the colloidal component was fractionated by gel filtration chromatography method. Gel filtration chromatographic fractionation of the colloids revealed two brown-coloured bands which had distinctive UV/Vis spectral features. The first eluting band had larger and more aromatic HS molecules than the second band, and in addition both P and Fe were primarily associated with the larger, more aromatic HS. This result demonstrated that P was able to form complexes with Fe-rich components of HS, and thus provided a scientific basis for the significant correlation between [Fe] and [TP] that the previous monitoring data of reference condition lochs from Scottish Environment Protection Agency (SEPA) showed. The distinctive features of the HS will be used as the basis for an improved spectroscopic tool.

Keywords: total phosphorus, humic substances, Scottish loch water, WFD model

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Authors: K. M. Etmimi, A. A. Sghayer, A. M. Gsiea, A. M. Abutruma

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Relatively few chemical species can be incorporated into diamond during CVD growth, and until recently the uptake of oxygen was thought to be low perhaps as a consequence of a short surface residence time. Within the literature, there is speculation regarding spectroscopic evidence for O in diamond, but no direct evidence. For example, the N3 and OK1 EPR centres have been tentatively assigned models made up from complexes of substitutional N and substitutional oxygen. In this study, we report density-functional calculations regarding the stability, electronic structures, geometry and hyperfine interaction of substitutional oxygen in diamond and show that the C2v, S=1 configuration very slightly lower in energy than the other configurations (C3v, Td, and C2v with S=0). The electronic structure of O in diamond generally gives rise to two defect-related energy states in the band gap one a non-degenerate a1 state lying near the middle of the energy gap and the other a threefold-degenerate t2 state located close to the conduction band edges. The anti-bonding a1 and t2 states will be occupied by one to three electrons for O+, O and O− respectively.

Keywords: DFT, oxygen, diamond, hyperfine

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Authors: Bolysbek Utelbayev, Tasmagambetova Aigerim, Toktasyn Raila, Markayev Yergali, Myrzakhanov Maxat

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Intensive development of secondary processes of destructive processing of crude oil has led to the occurrence of oil refining factories resources of C2-C4 hydrocarbons. Except for oil gases also contain basically C2-C4 hydrocarbon gases where some of the amounts are burned. All these data has induced interest to the study of producing alkylate from hydrocarbons С2-С4 which being as components of motor fuels. The purpose of this work was studying transformation propane-propene, butane-butene fractions at the presence of the ruthenium-chromic support catalyst whereas the carrier is served pillar - structural montmorillonite containing in native bentonite clay. In this work is considered condition and structure of the bentonite clay from the South-Kazakhstan area of the Republic Kazakhstan. For preparation rhodium support catalyst (0,5-1,0 mass. % Rh) was used chloride of rhodium-RhCl3∙3H2O, as a carrier was used modified bentonite clay. For modifying natural clay to pillar structural form were used polyhydroxy complexes of chromium. To aqueous solution of chloride chromium gradually flowed the solution of sodium hydroxide at gradual hashing up to pH~3-4. The concentration of chloride chromium was paid off proceeding from calculation 5-30 mmole Cr3+ per gram clay. Suspension bentonite (~1,0 mass. %) received by intensive washing it in water during 4 h, pH-water extract of clay makes -8-9. The acidity of environment supervised by means of digital pH meter OP-208/1. In order to prevent coagulation of a solution polyhydroxy complexes of chromium, it was slowly added to a suspension of clay. "Reserve of basicity" Cr3+:/OH-allowing to prevent coagulation chloride of rhodium made 1/3. After endurance processed suspensions of clay during 24 h, a deposit was washed by water and condensed. The sample, after separate from a liquid phase, dried at first at the room temperature, and then at 110°C (2h) with the subsequent rise the temperature up to 180°C (4h). After cooling the firm mass was pounded to a powder, it was shifted infractions with the certain sizes of particles. Fractions of particles modifying clay in the further were impregnated with an aqueous solution with rhodium-RhCl3∙3H2O (0,5-1,0 mаss % Rh ). Obtained pillar structural bentonite approaches heat resistance and its porous structure above the 773K. Pillar structural bentonite was used for preparation 1.0% Ru/Carrier (modifying bentonite) support catalysts where is realised alkylation of C2-C4 hydrocarbons. The process of alkylation is carried out at a partial pressure of hydrogen 0.5-1.0MPa. Outcome 2.2.4 three methyl pentane and 2.2.3 trimethylpentane achieved 40%. At alkylation butane-butene mixture outcome of the isooctane is achieved 60%. In this condition of studying the ethene is not undergoing to alkylation.

Keywords: alkylation, butene, pillar structure, ruthenium catalyst

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Authors: Amit Chaudhary, B. S. Yadav, P. K. Maurya, A. M., S. Srivastava, S. Singh, A. Mani

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Cold shock protein A (CspA) is major cold inducible protein present in Escherichia coli. The protein is involved in stabilizing secondary structure of RNA by working as chaperone during cold temperature. Two RNA binding motifs play key role in the stabilizing activity. This study aimed to investigate implications of low temperature on structure and RNA binding activity of E. coli CspA. Molecular dynamics simulations were performed to compare the stability of the protein at 37°C and 10 °C. The protein was mutated at RNA binding motifs and docked with RNA to assess the stability of both complexes. Results suggest that CspA as well as CspA-RNA complex is more stable at low temperature. It was also confirmed that RNP1 and RNP2 play key role in RNA binding.

Keywords: CspA, homology modelling, mutation, molecular dynamics simulation

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