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291.
Jelena Ivancic-Jelecki Marija BrglesMaja Šantak Dubravko Forcic 《Journal of chromatography. A》2009,1216(13):2717-2724
Human plasma is an important medical substance and a raw material for production of various therapeutics. During blood sampling, storage and processing, genomic DNA is released into plasma from nucleated blood cells that are damaged in the course of the procedure. In order to determine the concentration of contaminating DNA in plasma, we developed a method for DNA isolation by using anion-exchange chromatography on a BIA Separations CIM (convective interaction media) diethylaminoethyl column. DNA was quantified by SYBR Green based real-time polymerase chain reaction. The concentration of cell-free, non-apoptotic DNA in plasma ranged between 0.06 and 22.5 ng/ml. As substantial volumes of plasma or whole blood are administered directly into the vascular system, a recipient is exposed to high amounts of cell-free DNA, several orders of magnitude higher than the amount found in other biologicals. 相似文献
292.
Jelena Belosevic-Cavor Vasil Koteski Bozidar Cekic Giorgio Spano 《Journal of Physics and Chemistry of Solids》2005,66(10):1815-1819
A detailed theoretical study of the structure, electronic properties and the electric field gradients of the Hf2Fe intermetallic compound is presented. Using all-electron full-potential linearized augmented plane wave (FP-LAPW) formalism the equilibrium volume, bulk modulus and electric field gradients are calculated. The obtained results are compared with EFG values inferred from measurements performed using Mössbauer spectroscopy and the earlier reported time differential perturbed angular correlation (TDPAC) measurements. The lattice relaxation and the supercell calculations are found to be essential for the correct interpretation of the experimental results. 相似文献
293.
Filip Lj. Andrić Jelena Đ. Trifković Živoslav Lj. Tešić Dusanka M. Milojković-Opsenica 《Chromatographia》2008,68(5-6):453-458
In order to elucidate the influence of the mobile phase composition on the retention of some 1-aralkyl-4-arylpiperazines, Snyder’s selectivity and polarity concept for building a simple linear solvation energy relationships model of chromatographic behavior was used. Maximum variability of mobile phase selectivity was achieved by using ternary mixtures of solvents from three different corners of the Snyder selectivity triangle: methanol as a strong proton donor, acetone as a strong proton acceptor and dimethyl formamide as a dipole interactor. Water was added to keep elution strength constant. Mobile phase composition was varied using Simplex–lattice mixture design. Selectivity parameters were calculated on the basis of linear relationships between volume fractions of pure solvents and their χ e , χ d , χ n values. For seven-substituted 1-aralkyl-4-arylpiperazines R M values were measured and correlated with previously calculated selectivity parameters. Mathematical models obtained are discussed according to the structural properties of the studied compounds. 相似文献
294.
The synthesis of various functionalized or spirobicyclic glutarimides by a novel tandem process has been disclosed. The reaction involves a base-catalyzed Michael addition of active methylene compounds to secondary conjugated amides, followed by intramolecular N-acylation of the carboxamido group. It provides a relatively general and simple access to useful synthetic intermediaries and potentially active pharmacological compounds. In addition, a novel group of spirobicyclic systems has been synthesized. 相似文献
295.
Jelena Vasiljević Marija Gorjanc Brigita Tomšič Boris Orel Ivan Jerman Miran Mozetič Alenka Vesel Barbara Simončič 《Cellulose (London, England)》2013,20(1):277-289
The surface modification of cellulose fibres was performed with the use of low-pressure water vapour plasma, followed by the application of a pad-dry-cure sol–gel coating with the water- and oil-repellent organic–inorganic hybrid precursor fluoroalkyl-functional siloxane (FAS), with the aim of creating the “lotus effect” on the cotton fabric surface. The tailored “lotus effect” was confirmed by measurements of the contact angle of water (154°) and n-hexadecane (140°), as well as by measurements of the water sliding angle (7°), which were used to identify the super-hydrophobic, oleophobic and self-cleaning properties of the modified fibres. The chemical and morphological changes caused by modifications of the fibres were investigated by XPS, FTIR, AFM and SEM. The results show that the plasma pre-treatment simultaneously increased the surface polarity, average roughness, and surface area of the fabric. The application of the FAS coating after plasma pre-treatment caused only a slight increase in the surface roughness, accompanied by a decrease in the surface area, indicating that the architecture of the surface was significantly changed. This result suggests that the surface pattern affected the “lotus effect” more than the average surface roughness. The plasma pre-treatment increased the effective concentration of the FAS network on the fabric, which resulted in enhanced repellency before and after repetitive washing, compared with that of the FAS-coated fabric sample without the plasma pre-treatment. Despite the fact that the plasma pre-treatment increased the concentration of the oxygen-containing functional groups on the fabric surface, this phenomenon insignificantly contributed to the adhesion ability and, consequently, the washing fastness of the FAS coating. 相似文献
296.
Anamarija Stankovi
ana Kajini Jelena Veligaj Turkalj
eljka Romi Maja Dutour Sikiri Abdelilah Asserghine Geza Nagy Martina Medvidovi‐Kosanovi 《Electroanalysis》2020,32(5):1043-1051
In this study, glassy carbon electrode modified with nano gold‐crystal violet film has been used to detect arsenite (As (III)) in a model system and in groundwater samples. The modified electrode was characterized by scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS). Using voltammetric measuring technique, linear response was obtained in a concentration range of 2.0–22.0 μM. The arsenite concentrations in groundwater samples varied between 2.4 μM to 4.8 μM. The sensitivity of the modified electrode for As (III) detection was 5.6 μA/μM cm2 and 0.8 μM concentration was found as lower limit of detection (LOD). The accuracy of the method was checked with standard method anodic stripping voltammetry (ASV). Groundwater samples were characterized with dynamic (DLS) and electrophoretic (ELS) light scattering measurements which have shown that particles present in different samples differ in size distribution and zeta potential which did not interfere with As (III) detection. 相似文献
297.
Jelena Dodić Jovana Grahovac Nataša Kalajdžija Strahinja Kovačević Lidija Jevrić Sanja Podunavac Kuzmanović 《Applied biochemistry and biotechnology》2014,174(2):534-541
The nutritional requirements for antimicrobial agent production using Streptomyces hygroscopicus were analyzed in shake flask experiments. Antimicrobial activity was tested against Staphylococcus aureus and Bacillus cereus. The mathematical models have been generated with relative high complexity in order to give an adequate fit to the data. All the results suggest a high dependence of produced antimicrobial agent quantities on the amount of carbon, nitrogen, and phosphorus in cultivation medium. The statistical results of the generated models reflect the high predictive ability. The derived models were validated using leave-one-out cross-validation technique, and from statistical point of view, they have significantly high values of the cross-validation parameters. 相似文献
298.
Extrusion of immiscible polymer biphasic blends to form in situ microfibers of the minor component in the matrix of the major component is an elegant way to create composites with new properties. The process was used to obtain thermoplastic polyurethane elastomers modified with polypropylene microfibers. The effect of phase interaction on blend morphology and properties was studied by running a series of blends with and without a maleated polypropylene compatibilizer. Six different blends were prepared: three with compatibilizer and three without the compatibilizer. All blends contained polypropylene as a minor component (80/20; 90/10 and 95/5). Extrusion spinning of polyurethane/polypropylene blends with and without compatibilizer resulted in polyurethane fibers modified with highly-oriented polypropylene microfibrils at all component ratios. Increasing polypropylene concentration in the thermoplastic polyurethane matrix increased hardness and modulus, but did not affect tensile strength and lowered elastic recovery. 相似文献
299.
Barbara Simončič Samira Hadžić Jelena Vasiljević Lidija Černe Brigita Tomšič Ivan Jerman Boris Orel Jožef Medved 《Cellulose (London, England)》2014,21(1):595-605
This research aimed to create multifunctional cellulose fibres with water- and oil-repellent, self-cleaning, and flame retardant properties. A sol mixture of fluoroalkyl-functional siloxane, organophosphonate and methylol melamine resin was applied to cotton fabric by the pad-dry-cure method. Successful coating was verified by atomic force microscopy and Fourier transform infrared spectroscopy. The functional properties of the coated fibres were investigated using the static contact angles of water and n-hexadecane, the water sliding angles, the vertical test of flammability, the limiting oxygen index, and simultaneous thermal analysis. The results reveal that a homogeneous composite inorganic–organic polymer film formed on the cotton fabric surface exhibited the following properties: static contact angle of water of 150° and of n-hexadecane of 128°, water sliding angle of 10°, limiting oxygen index of 34 %, and high thermal stability. These results demonstrate the synergistic activity of the compounds in the coating, which resulted in the creation of a “lotus effect” on the fabric surface as well as excellent flame retardancy and thermal stability. 相似文献
300.
Scorpionate‐Type Coordination in MFU‐4l Metal–Organic Frameworks: Small‐Molecule Binding and Activation upon the Thermally Activated Formation of Open Metal Sites
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Dmytro Denysenko Dr. Maciej Grzywa Dr. Jelena Jelic Prof. Dr. Karsten Reuter Prof. Dr. Dirk Volkmer 《Angewandte Chemie (International ed. in English)》2014,53(23):5832-5836
Postsynthetic metal and ligand exchange is a versatile approach towards functionalized MFU‐4l frameworks. Upon thermal treatment of MFU‐4l formates, coordinatively strongly unsaturated metal centers, such as zinc(II) hydride or copper(I) species, are generated selectively. CuI‐MFU‐4l prepared in this way was stable under ambient conditions and showed fully reversible chemisorption of small molecules, such as O2, N2, and H2, with corresponding isosteric heats of adsorption of 53, 42, and 32 kJ mol?1, respectively, as determined by gas‐sorption measurements and confirmed by DFT calculations. Moreover, CuI‐MFU‐4l formed stable complexes with C2H4 and CO. These complexes were characterized by FTIR spectroscopy. The demonstrated hydride transfer to electrophiles and strong binding of small gas molecules suggests these novel, yet robust, metal–organic frameworks with open metal sites as promising catalytic materials comprising earth‐abundant metal elements. 相似文献