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81.
E. B. Coropceanu L. M. Croitor Yu. M. Chumakov M. S. Fonari 《Crystallography Reports》2009,54(5):837-840
The crystal structure of [Cu2(DfH)4(4,4′-Bipy)] · 2DMF prepared by the reaction of copper(II) acetate with diphenylglyoxime (DfH2) and 4,4′-bipyridine (4,4′-Bipy) was established by X-ray diffraction. The crystals are monoclinic; a = 15.5192(9) Å, b = 16.2427(11) Å, c = 14.0753(7) Å, β = 101.36(3)°, V = 3478.5(5) Å3, Z = 2, and sp. gr. P21/c. The crystal structure is composed of discrete dinuclear molecules [Cu2(DfH)4(4,4′-Bipy)] and dimethylformamide (DMF) molecules. The coordination polyhedron of the Cu atom (the coordination number is 5) is a tetragonal bipyramid formed by the nitrogen atoms of two monodeprotonated bidentate oxime groups and the bidentate bridging 4,4′-Bipy ligand. The DMF molecules occupy the cavities formed by the dinuclear molecules [Cu2(DfH)4(4,4′-Bipy)]. The compound was characterized by IR and NMR spectroscopy. 相似文献
82.
Carla?R.?Borges Ricardo?E.?Samad Karina?de?Oliveira Gon?alves Daniel?Perez?Vieira Lilia?C.?CourrolEmail authorView authors OrcID profile 《Journal of nanoparticle research》2018,20(6):166
Silver nanoparticles (AgNPs) have been intensively studied for several purposes including therapeutic applications in cancer. When prepared with tryptophan and photoreduction, silver nanoparticles (TrpAgNPs) become an alternative to conventional anticancer drugs. In this study, the anticancer activity of synthesized TrpAgNPs against MCF-7 breast cancer cells was evaluated, and the inhibitory concentration (IC50) was found to be ~3.4 mg/mL. Since the protoporphyrin IX (PPIX) concentrations in tumor cells are elevate compared to normal cells, the PPIX-TrpAgNP interaction was studied to investigate if it could contribute for cell apoptosis. The investigation was performed using PPIX solution (0.9 μg/mL) with different TrpAgNP concentrations (from 0 to 13 mg/mL). PPIX was characterized by UV-Vis spectroscopy, steady-state and time-resolved fluorescence spectroscopy. The results have shown that the presence of spherical TrpAgNps with 16-nm diameter quench the PPIX fluorescence intensity. This quenching is strongly dependent on the concentration of the TrpAgNPs, and it is caused by a combination of a static and a dynamic process. The chemical binding leads to oxidation of tryptophan and formation of kynurenine, observed in the emission spectra around 470 nm. The strong reduction of the PPIX fluorescence decay lifetime with nanoparticle increasing concentration confirms the quenching processes due to charge transfer from the excited PPIX states to the resonant silver states. The present study confirms the anticancer activity of TrpAgNPs on the human breast cancer cell line (MCF-7) in vitro and indicates that PPIX-AgNP interaction could contribute with MCF-7 apoptosis. 相似文献
83.
José A. Flores-Livas Miglė Graužinytė Lilia Boeri Gianni Profeta Antonio Sanna 《The European Physical Journal B - Condensed Matter and Complex Systems》2018,91(8):176
In this work we study the pressure-dependent phase diagram of polyethylene (H2C)x from 50 to 200 GPa. Low-symmetry, organic polymeric phases, that are dynamically stable and thermodynamically competitive with elemental decomposition, are reported. Electronic structure calculations reveal that the band gap of the lowest energy polymeric phase decreases from 5.5 to 4.5 eV in the 50–200 GPa range, but metalization occurs only for pressures well above 500 GPa. The possibility of metalization via doping was also investigated, observing that it can be achieved through boron substitution at carbon sites. We report a sizable electron-phonon coupling (λ ? 0.79) in this metallic phase, with an estimated superconducting transition temperature of about 35 K. However, a rather narrow domain of stability is found; most of the dopant elements render the polymeric phases unstable and induce amorphization. This suggests that doping under pressure, though presenting an alternative route to find high temperature superconductors, would be challenging to achieve experimentally. 相似文献
84.
We present a transversal alternating field electrophoresis chamber that allows modifiable inner widths to accommodate low- or high-throughput formats, with 7.8 cm opposite electrode separation and 30.4 cm electrode length. Removable slotted sheets divide the chamber into four smaller compartments, each one supporting a minigel of 3.85 cm in length and 7.1 cm in width. Replacements of slotted sheets with solid dielectric blocks with the sizes and shapes of compartments permit to occlude chamber compartments, changing from 4 to 1 the numbers of minigels per run, from 88 to 13 the maximum numbers of samples, and from 1688 to 422 mL the volume of buffer poured into the chamber. Saccharomyces cerevisiae chromosomes gave its characteristic DNA band pattern in all compartments, whereas migrations of DNA molecules are not affected by the occlusion of compartments. 相似文献
85.
Olga Danilescu Paulina N. Bourosh Oleg Petuhov Olga V. Kulikova Ion Bulhac Yurii M. Chumakov Lilia Croitor 《Molecules (Basel, Switzerland)》2021,26(8)
Based on solvothermal synthesis, self-assembly of the heptadentate 2,6-diacetylpyridine bis(nicotinoylhydrazone) Schiff base ligand (H2L) and Zn(II) and/or Cd(II) salts has led to the formation of three homometallic [CdL]n (1), {[CdL]∙0.5dmf∙H2O}n (2) and {[ZnL]∙0.5dmf∙1.5H2O}n (3), as well as two heterometallic {[Zn0.75Cd1.25L2]∙dmf∙0.5H2O}n (4) and {[MnZnL2]∙dmf∙3H2O}n coordination polymers. Compound 1 represents a 1D chain, whereas 2–5 are isostructural and isomorphous two-dimensional structures. The entire series was characterized by IR spectroscopy, thermogravimetric analysis, single-crystal X-ray diffraction and emission measurements. 2D coordination polymers accommodate water and dmf molecules in their cage-shaped interlayer spaces, which are released when the samples are heated. Thus, three solvated crystals were degassed at two temperatures and their photoluminescent and adsorption–desorption properties were recorded in order to validate this assumption. Solvent-free samples reveal an increase in volume pore, adsorption specific surface area and photoluminescence with regard to synthesized crystals. 相似文献
86.
Yearin Byun Lilia S. Xie Patrick Fritz Timur Ashirov Mircea Dinc Ali Coskun 《Angewandte Chemie (International ed. in English)》2020,59(35):15166-15170
Dimensionality plays an important role in the charge transport properties of organic semiconductors. Although three‐dimensional semiconductors, such as Si, are common in inorganic materials, imparting electrical conductivity to covalent three‐dimensional organic polymers is challenging. Now, the synthesis of a three‐dimensional π‐conjugated porous organic polymer (3D p‐POP) using catalyst‐free Diels–Alder cycloaddition polymerization followed by acid‐promoted aromatization is presented. With a surface area of 801 m2 g?1, full conjugation throughout the carbon backbone, and an electrical conductivity of 6(2)×10?4 S cm?1 upon treatment with I2 vapor, the 3D p‐POP is the first member of a new class of permanently porous 3D organic semiconductors. 相似文献
87.
Martínez-Luis S Cherigo L Arnold E Spadafora C Gerwick WH Cubilla-Rios L 《Natural product communications》2012,7(2):165-168
With the combined goal of finding the best anti-parasitic and anti-cancer activities as well as isolating the bioactive agents and studying their structures and biological properties, we proceeded to perform a small-scale cultivation of Aspergillus sp. strain F1544 using Potato Dextrose, Malt Extract, Czapek Dox and Eight Vegetables media. From the more promising extracts (obtaining using potato dextrose and czapek dox media in large scale) of this fungus, we isolated the five compounds: pseurotin A (1), 14-norpseurotin A (2), FD-838 (3), and pseurotin D (4), and fumoquinone B (5). All compounds showed good antileishmanial and moderate anticancer activities. 相似文献
88.
Chafia Sobhi Abdelmalek Khorief Nacereddine Lilia Nasri Zohra Lechtar Abdelhafid Djerourou 《Molecular physics》2013,111(21):3193-3200
A DFT study of the (32CA) reaction of a series of some nitrile oxides with electron-deficient alkyne (3-phenylpropionlaldehyde) in gas phase and in toluene has been carried out using B3LYP functional with 6-31G(d) basis set. Two reactive channels 4- and 5-associated with the two regioisomeric modes have been located and characterised. These 32CA reactions are characterised by a low asynchronous one-step mechanism with a low-polar character. Analysis of the DFT reactivity indices indicates that the nucleophilic centre of the different nitrile oxides accounts for the 4-regioselectivity. Our calculations are in a good agreement with the experimental findings. 相似文献
89.
S. Furquan Ahmad Lilia A. Chtcheglova Barbara Mayer Sergei A. Kuznetsov Peter Hinterdorfer 《Analytical and bioanalytical chemistry》2011,399(7):2359-2367
Determining the distribution of specific binding sites on biological samples with high spatial accuracy (in the order of several
nanometer) is an important challenge in many fields of biological science. Combination of high-resolution atomic force microscope
(AFM) topography imaging with single-molecule force spectroscopy provides a unique possibility for the detection of specific
molecular recognition events. The identification and localization of specific receptor binding sites on complex heterogeneous
biosurfaces such as cells and membranes are of particular interest in this context. Simultaneous topography and recognition
imaging was used to unravel the nanolandscape of cells of the immune system such as macrophages. The most studied phagocytic
receptors include the Fc receptors that bind to the Fc portion of immunoglobulins. Here, nanomapping of FcγRs (Fc receptors
for immunoglobulin G (IgG)) was performed on fixed J774.A1 mouse macrophage cell surfaces with magnetically coated AFM tips
functionalized with Fc fragments of mouse IgG via long and flexible poly(ethylene glycol) linkers. Because of possible AFM
tip engulfment on living macrophages, appropriate cell fixation procedure leaving the binding activity of FcγRs practically
intact was elaborated. The recognition maps revealed prominent spots (microdomains) more or less homogeneously distributed
on the macrophage surface with the sizes from 4 to 300 nm. Typical recognition image contained about ∼4% of large clusters
(>200 nm), which were surrounded by a massive number (∼50%) of small-size (4–30 nm) and the rest by middle-size (50, 150 nm)
domains. These spots were detected from the decrease of oscillation amplitude during specific binding between Fc-coated tip
and FcγRs on macrophage surfaces. In addition, the effect of osmotic swelling on the topographical landscape of macrophage
surfaces and on the reorganization of FcγRs was investigated. 相似文献
90.
In this work, the reactions of various copper ions with 1,3,3-trimethyl-2-[5-(1,3,3-trimethyl-1,3-dihydro-indol-2-ylidene)-penta-1,3-dienyl]-3H-indolium--more commonly known as dimethylindodicarbocyanine polymethyne dye (DIDC)--as well as the application of the results obtained for the development of a spectrophotometric method for the determination of Cu(I), Cu(II) and Cu(III) are described. Cu(I) and Cu(II) in the presence of chloride ions and DIDC reagent are extractable by a variety of organic solvents. It is important to emphasize that Cu(I) was extracted under considerably different experimental conditions than Cu(II). The optimum conditions for the extraction of the Cu ion associates with DIDC by amyl acetate and the determination of Cu(I) and Cu(II) were found to be: pH 3-5 and pH 3-6 and chloride concentrations of 0.5-0.8 mol L(-1) and 3-6 mol L(-1) for Cu(I) and Cu(II), respectively. The molar absorptivities for Cu(I) and Cu(II) are 1.8x10(5) L mol(-1) cm(-1) and 1.2x10(5) L mol(-1) cm(-1), respectively. A reaction mechanism is suggested. Cu(III) does not extract in the presence of chloride ions. However, Cu(III) is a strong oxidative agent which can cause the decolourisation of the DIDC reagent. The optimum conditions for Cu(III) determination were found to be: 2x10(-5) mol L(-1) DIDC; pH 8; water:acetone 4:1 medium. The developed procedures were tested for the determination of Cu(I), Cu(II) and Cu(III) in semiconductor samples. 相似文献