Repozitorij Univerze v Novi Gorici

Iskanje po repozitoriju
A+ | A- | Pomoč | SLO | ENG

Iskalni niz: išči po
išči po
išči po
išči po
* po starem in bolonjskem študiju

Opcije:
  Ponastavi


31 - 40 / 41
Na začetekNa prejšnjo stran12345Na naslednjo stranNa konec
31.
Naked protein nanoparticles
Ario De Marco, 2017, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje)

Ključne besede: Protein nanoparticles, targeted delivery, cell uptake
Objavljeno v RUNG: 15.12.2017; Ogledov: 3560; Prenosov: 415
.pdf Celotno besedilo (2,09 MB)

32.
Photoelectrochemical Water Splitting Studies with nanostructured n and p-type semiconductor electrodes
Saim Emin, Matjaž Valant, 2017, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje)

Opis: Photoelectrochemical water splitting has been demonstrated as a promising way to efficiently split water. Currently, solar-to-hydrogen conversion efficiency using state-of-the-art material combinations in PEC system is in the order of 7%. Fabrication of nanostructured materials with unique morphologies and compositions is an important factor to fully utilize the possibilities in this field. We will present different strategies for the preparation of nanostructured metal oxide thin films by using electrodeposition and wet-chemistry techniques. Focus will be given on the preparation of ZnO and CuO thin films where intermediate phases like Zn(OH)8Cl2.H2O and CuX (X=Br, Cl) were electrodeposited. Wet-chemistry synthesis techniques will be also explored for the preparation of nanostructured WO3 and a-Fe2O3 thin films. Especially, the hot-pyrolysis technique for the preparation of colloidal W and Fe/Fe-oxide nanoparticles will be shown. Spin-coating of W and Fe/Fe-oxide NPs onto optically conductive substrates and subsequent heat treatment of the obtained films was found to be a convenient way for the preparation of nanostructured WO3 and a-Fe2O3 thin films.
Ključne besede: photoelectrochemical water splitting, colloidal nanoparticles, semiconductor
Objavljeno v RUNG: 24.10.2017; Ogledov: 4608; Prenosov: 0
Gradivo ima več datotek! Več...

33.
Metal oxide and metal carbides thin films for photo/electrochemical water splitting studies
Saim Emin, 2017, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: We used wet-chemistry techniques to prepare colloidal tungsten (W) nanoparticles (NPs). The synthesis of W NPs was conducted using the so called hot-matrix method in 1-octadecene [1]. The sizes of obtained W NPs are in the order of 2 - 5 nm. These W NPs are coated with hydrophobic molecules which allow their dispersion in organic solvents like choloroform (CHCl3). It was found that the colloidal stability of the dispersions is exceptionally high exceeding several years. The stability of W NPs which prevents coagulation allows the preparation of thin films with uniform thicknesses by spin-coating, inkjet-printing and spray coating. We have prepared both tungsten trioxide (WO3) and tungsten carbide (W2C, WC) thin films. The preparation of WO3 thin films was achieved by spin-coating of W NPs on fluorine doped tin oxide (FTO) glass substrates and following thermal treatment in air at 500°C. The preparation of W2C and WC were done after spin-coating of W NPs on graphite substrate and following heat treatment under Ar atmosphere at 1000 and 1450°C. The obtained WO3 and W2C (e.g WC) films were used both in photo/electrochemical water splitting studies. In conclusion, we have developed a procedure for the synthesis of W NPs which can be used for the preparation of different class of materials for water splitting studies.
Ključne besede: metal oxides, metal carbides, tungsten nanoparticles
Objavljeno v RUNG: 09.10.2017; Ogledov: 5488; Prenosov: 0
Gradivo ima več datotek! Več...

34.
Tungsten carbide thin films for electrochemical water splitting studies
Saim Emin, Cesur Altinkaya, Ali Semerci, Matjaž Valant, Hasan Okuyucu, Abdullah Yildiz, 2017, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: We used wet-chemistry techniques to prepare colloidal tungsten (W) nanoparticles (NPs). The synthesis of W NPs was conducted using the so called hot-matrix method in 1-octadecene [1]. The sizes of obtained W NPs are in the order of 2 - 5 nm. These W NPs are coated with hydrophobic molecules which allow their dispersion in organic solvents like choloroform (CHCl3). It was found that the colloidal stability of the dispersions is exceptionally high exceeding several years. The stability of W NPs which prevents coagulation allows the preparation of thin films with uniform thicknesses by spin-coating, inkjet-printing and spray coating. We have prepared tungsten carbide (W2C, WC) thin films. The preparation of W2C and WC was achieved by spin-coating of pre-synthesized W NPs on graphite substrate and following heat treatment under Ar atmosphere at 1000 and 1450°C. The obtained W2C and WC films were used both in electrochemical water splitting studies. We also made a composite W2C-Pt films where we used only 5 at.% of Pt. The W2C-Pt composite has shown similar performance as pure Pt-C for hydrogen (H2) evolution. In conclusion, we have developed a procedure for the synthesis of W NPs which can be applied for the preparation of tungsten carbides films and their use for electrochemical water splitting.
Ključne besede: water splitting, nanoparticles, hot-matrix
Objavljeno v RUNG: 09.10.2017; Ogledov: 6176; Prenosov: 0
Gradivo ima več datotek! Več...

35.
Facile synthesis, structure, biocompatibility and antimicrobial property of gold nanoparticle composites from cellulose and keratin
Chieu D. Tran, Franja Prosenc, Mladen Franko, 2018, izvirni znanstveni članek

Opis: A novel, one-pot method was developed to synthesize gold nanoparticle composite from cellulose (CEL), wool keratin (KER) and chloroauric acid. Two ionic liquids, butylmethylimmidazolium chloride and ethylmethylimmidazolium bis(trifluoromethylsulfonyl)imide were used to dissolve CEL, KER and HAuCl4. X-ray diffraction and X-ray photoelectron results show that Au3+ was completely reduced to Au0NPs with size of (5.5 ± 1) nm directly in the composite with NaBH4. Spectroscopy and imaging results indicate that CEL and KER remained chemically intact and were homogeneously distributed in the com- posites with Au0NPs. Encapsulating Au0NPs into [CEL+KER] composite made the composite fully biocom- patible and their bactericidal capabilities were increased by the antibacterial activity of Au0NPs. Specifically, the [CEL+KER+Au0NPs] composite exhibited up to 97% and 98% reduction in growth of antibi- otic resistant bacteria such as vancomycin resistant Enterococcus faecalis and methicillin resistant Staphylococcus aureus, and was not cytotoxic to human fibroblasts. While [CEL+KER] composite is known to possess some antibacterial activity, the enhanced antibacterial observed here was due solely to added Au0NPs. These results together with our previous finding that [CEL+KER] composites can be used for con- trolled delivery of drugs clearly indicate that the [CEL+KER+Au0NPs] composites possess all required properties for successful use as dressing to treat chronic ulcerous infected wounds.
Ključne besede: Ionic liquid Green Sustainable Polysaccharide Keratin Wound dressing Gold nanoparticles Antibiotic-resistant bacteria
Objavljeno v RUNG: 27.09.2017; Ogledov: 4532; Prenosov: 0
Gradivo ima več datotek! Več...

36.
Biotransformation of copper oxide nanoparticles by the pathogenic fungus Botrytis cinerea
Eva Kovačec, Marjana Regvar, Johannes Teun van Elteren, Iztok Arčon, Tamás Papp, Darko Makovec, Katarina Vogel-Mikuš, 2017, izvirni znanstveni članek

Opis: Two plant pathogenic fungi, Botrytis cinerea and Alternaria alternata, isolated from crop plants, were exposed to Cu in ionic (Cu2þ), microparticulate (MP, CuO) or nanoparticulate (NP, Cu or CuO) form, in solid and liquid culturing media in order to test fungal response and toxic effects of the mentioned compounds for the potential use as fungicides. B. cinerea has shown pronounced growth and lower levels of lipid peroxidation compared to A. alternata. Its higher resistance/tolerance is attributed mainly to biotransformation of CuO and Cu NPs and CuO MPs into a blue compound at the fungal/culturing media interface, recognized by Cu K-edge EXAFS analysis as Cu-oxalate complex. The pronounced activity of catechol-type siderophores and organic acid secretion in B. cinerea induce leaching and mobilization of Cu ions from the particles and their further complexation with extracellularly secreted oxalic acid. The ability of pathogenic fungus to biotransform CuO MPs and NPs hampers their use as fungicides. However the results show that B. cinerea has a potential to be used in degradation of Cu(O) nanoparticles in environment, copper extraction and purification techniques.
Ključne besede: copper, metal oxide nanoparticles, detoxification mechanisms, metal pollution, Cu-oxalate
Objavljeno v RUNG: 23.08.2017; Ogledov: 4505; Prenosov: 0
Gradivo ima več datotek! Več...

37.
38.
Biotinylated Vanadium and Chromium Sulfide Nanoparticles as Probes for Colocalization of Membrane Proteins
Alexandre Loukanov, Saim Emin, 2016, izvirni znanstveni članek

Opis: ABSTRACT We report the microemulsion synthesis of vanadium and chromium sulfide nanoparticles (NPs) and their biological application as nanoprobes for colocalization of membrane proteins. Spherical V2S3 and Cr2S3 NPs were prepared in reverse microemulsion droplets, as nanoreactors, obtained by the surfactant sodium bis(2-ethylhexyl) sulfosuccinate (AOT) in nonpolar organic phase (heptane). Electron microscopic data indicated that the size distribution of the nanoparticles was uniform with an average diameter between 3 4 5 nm. The prepared hydrophobic nanocrystals were transferred in aqueous phase by surface cap exchange of AOT with biotindihydrolipoic ligands. This substitution allows the nanoparticles solubility in aqueous solutions and confer their bioactivity. In addition, we report the conjugation procedure between a-Lipoic acid (LA) and biotin (abbreviated as biotin-LA). The biotin-LA structure was characterized by 1D and 2D NMR spectroscopy. The biotinylated vanadium and chromium sulfide nanoparticles were tested as probes for colocalization of glutamate receptors on sodium-dodecyl-sulfate-digested replica prepared from rat hippocampus. The method suggests their high labeling efficiency for study of membrane biological macromolecules.
Ključne besede: biotin-dihydrolipoic conjugate, vanadium and chromium sulfide nanoparticles, membrane proteins
Objavljeno v RUNG: 02.02.2017; Ogledov: 5980; Prenosov: 0
Gradivo ima več datotek! Več...

39.
One-pot synthesis of biocompatible silver nanoparticle composites from cellulose and keratin: characterization and antimicrobial activity
Chieu Ding Tran, Franja Prosenc, Mladen Franko, Gerald Benzi, 2016, izvirni znanstveni članek

Opis: A novel, simple method was developed to synthesize biocompatible composites containing 50% cellulose (CEL) and 50% keratin (KER) and silver in the form of either ionic (Ag+) or Ag0 nanoparticle (Ag+NPs or Ag0NPs). In this method, butylmethylimmidazolium chloride ([BMIm+Cl-]), a simple ionic liquid, was used as the sole solvent and silver chloride was added to the [BMIm+Cl-] solution of [CEL+KER] during the dissolution process. The silver in the composites can be maintained as ionic silver (Ag+) or completely converted to metallic silver (Ag0) by reducing it with NaBH4. Results of spectroscopy (Fourier-transform infrared (FTIR), X-ray diffraction (XRD)) and imaging (scanning electron microscope (SEM)) measurements confirm that CEL and KER remain chemically intact and homogeneously distributed in the composites. Powder X-ray diffraction (XRD) and SEM results show that the silver in the [CEL+KER+Ag+] and [CEL+KER+Ag0] composites is homogeneously distributed throughout the composites in either Ag+ (in the form of Ag2O nanoparticles (NPs)) or Ag0NPs form with size of (9 ± 1) nm or (27 ± 2) nm, respectively. Both composites were found to exhibit excellent antibacterial activity against many bacteria including Escherichia coli, Staphylococus aureus, Pseudomonas aeruginosa, methicillin resistant Staphylococus aureus (MRSA), vancomycin resistant Enterococus faecalis (VRE). The antibacterial activity of both composites increases with the Ag+ or Ag0 content in the composites. More importantly, for the same bacteria and the same silver content, [CEL+KER+Ag0] composite exhibits relatively greater antimicrobial activity against bacteria compared to the corresponding [CEL+KER+Ag+] composite. Experimental results confirm that there was hardly any Ag0NPs release from the [CEL+KER+Ag0NPs] composite, and hence its antimicrobial activity and biocompatibility is due, not to any released Ag0NPs but rather entirely to the Ag0NPs embedded in the composite. Both Ag2ONPs or Ag0NPs were found to be toxic to human fibroblasts at higher concentration (>0.72 mmol), and that for the same silver content, [CEL+KER+Ag2ONPs] composite is relatively more toxic than [CEL+KER+Ag0NPs] composite. As expected, by lowering the Ag0NPs concentration to 0.48 mmol or less, the [CEL+KER+Ag0NPs] composite can be made biocompatible while still retaining its antimicrobial activity against bacteria such are E. coli, S. aureus, P. aeruginosa, MRSA, VRE. These results together with our previous finding that [CEL+KER] composites can be used for controlled delivery of drugs such as ciprofloxacin clearly indicate that the [CEL+KER+Ag0NPs] composite possess all required properties for successfully used as high performance dressing to treat chronic ulcerous infected wounds.
Ključne besede: Celulose, Keratin, Cmposites, Biocompatible, Ag nanoparticles, one-pot synthesis, Antibacterial, Antiviral
Objavljeno v RUNG: 28.11.2016; Ogledov: 5264; Prenosov: 0
Gradivo ima več datotek! Več...

40.
Packing patterns of silica nanoparticles on surfaces of armored polystyrene latex particles
Sara Fortuna, Catheline A. L. Colard, Stefan A. F. Bon, Alessandro Troisi, 2009, izvirni znanstveni članek

Opis: Fascinating packing patterns of identical spherical and discotic objects on curved surfaces occur readily in nature and science. Examples include C60 fullerenes,(1, 2)13-atom cuboctahedral metal clusters,(3) and S-layer proteins on outer cell membranes.(4) Numerous situations with surface-arranged objects of variable size also exist, such as the lenses on insect eyes, biomineralized shells on coccolithophorids,(5) and solid-stabilized emulsion droplets(6) and bubbles.(7) The influence of size variations on these packing patterns, however, is studied sparsely. Here we investigate the packing of nanosized silica particles on the surface of polystyrene latex particles fabricated by Pickering miniemulsion polymerization of submicrometer-sized armored monomer droplets. We are able to rationalize the experimental morphology and the nearest-neighbor distribution with the help of Monte Carlo simulations. We show that broadening of the nanoparticle size distribution has pronounced effects on the self-assembled equilibrium packing structures, with original 12-point dislocations or grain-boundary scars gradually fading out.
Ključne besede: packing patterns, silica, simulation, Monte Carlo, order, disorder, transition, armored particles, nanoparticles, Pickering emulsion
Objavljeno v RUNG: 10.10.2016; Ogledov: 4818; Prenosov: 0
Gradivo ima več datotek! Več...

Iskanje izvedeno v 0.06 sek.
Na vrh