Preparation and characterization of Thioflavin T doped silica nanoparticles

Fluorescent silica nanoparticles with diameters of about 300nm were synthesized based on Stober's method, using Thioflavin T as fluorescent co-reagent. The particles were characterized via transmission electron microscopy and fluorimetry measurements. Fluorescence intensity of the sols was ten times higher than that of the ethanol phase solutions of Thioflavin T. Release of dye molecules in stable alcosols was investigated by measuring UV-Vis absorbance spectrum of the supernatant. To try an alternative route, we investigated accumulation of dye molecules in native silica particles. No release effect was detected, and slow accumulation was observed. Water contact angles of the particles were assessed from analyzing the Langmuir films, and were found to be 18, very similar to native silica particles. Langmuir-Blodgett films of the particles were deposited on a glass substrate and were examined via UV-Vis spectrophotometry, fluorimetry and scanning electron microscopy. Presence of the film was revealed; the particles formed a continuous, well-packed monolaye

A bizalom egyes dimenzióinak szerepe a magyarországi termelői szerveződések életében

Sajnálatos tapasztalat, hogy amíg az Európai Unió meghatározó zöldség - gyümölcs előállító tagállamaiban a marketing szövetkezetek (pl. TÉSZ\ud - ek) meghatározó szerepet töltenek be a termékpálya koordinálásában, addig az Európai Unióhoz újonnan csatlakozott országokban, köztük Magyarországon piaci részesedésük meglehetősen alacsony. A témában végzett kutatások döntően egyetértenek abban, hogy e jelenség alapvetően a gazdálkodói bizalom alacsony szintjével magyarázható. Ezt a szituációt alapul véve, jelen tanulmány a bizalom szerepét vizsgálja a gazdálkodói szerveződések életében. A bizalom, mint kutatások tárgya, relatíve új jelenség az agrárközgazdasági kutatásokban, ugyanakkor ennek ellenére az elmúlt néhány évtizedben nagyszámú bizalom - definíció és kategorizálás vált ismertté. Ezen számos bizalom - megközelítésből kutatómunkánk során a McAllister- féle csoportosítást vettük alapul, mely a bizalom két dimenzióját azonosítja: kognitív és affektív. Kutatómunkánk során kérdőívezésen alapuló empirikus vizsg álatok keretében elemeztük a bizalom ezen két aspektusainak szerepét, illetve hatását a szövetkezetekben, különös tekintettel a csoportkohézióra, a tagok elégedettségére , valamint aktivitására

Calculation of the entropy of binary hard sphere mixtures from pair correlation functions

This is the publisher's version, also available electronically from http://scitation.aip.org/content/aip/journal/jcp/97/3/10.1063/1.463103.We evaluate the entropy of several binary hard sphere fluid mixtures using two approximate expressions that require as input only the pair correlation functions,g αβ(r). An approximation based on the incompressible limit is found to be accurate for medium to high density fluids

Thermodynamic and Kinetic Stabilities of Al(III) Complexes with N2O3 Pentadentate Ligands

: Al(III) complexes have been recently investigated for their potential use in imaging with positron emission tomography (PET) by formation of ternary complexes with the radioisotope fluorine-18 (18F). Although the derivatives of 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA) are the most applied chelators for [Al18F]2+ labelling and (pre)clinical PET imaging, non-macrocyclic, semi-rigid pentadentate chelators having two N- and three O-donor atoms such as RESCA1 and AMPDA-HB have been proposed with the aim to allow room temperature labelling of temperature-sensitive biomolecules. The paucity of stability data on Al(III) complexes used for PET imaging instigated a complete thermodynamic and kinetic solution study on Al(III) complexes with aminomethylpiperidine (AMP) derivatives AMPTA and AMPDA-HB and the comparison with a RESCA1-like chelator CD3A-Bn (trans-1,2-diaminocyclohexane-N-benzyl-N,N',N'-triacetic acid). The stability constant of [Al(AMPDA-HB)] is about four orders of magnitude higher than that of [Al(AMPTA)] and [Al(CD3A-Bn)], highlighting the greater affinity of phenolates with respect to acetate O-donors. On the other hand, the kinetic inertness of the complexes, determined by following the Cu2+-mediated transmetallation reactions in the 7.5-10.5 pH range, resulted in a spontaneous and hydroxide-assisted dissociation slightly faster for [Al(AMPTA)] than for the other two complexes (t1/2 = 4.5 h for [Al(AMPTA)], 12.4 h for [Al(AMPDA-HB)], and 24.1 h for [Al(CD3A-Bn)] at pH 7.4 and 25 °C). Finally, the [AlF]2+ ternary complexes were prepared and their stability in reconstituted human serum was determined by 19F NMR experiments

Thermodynamic stability, kinetic inertness and relaxometric properties of monoamide derivatives of lanthanide(III) DOTA complexes

A complete thermodynamic and kinetic solution study on lanthanide(III) complexes with monoacetamide (DOTAMA, L1) and monopropionamide (DOTAMAP, L2) derivatives of DOTA (DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) was undertaken with the aim to elucidate their stability and inertness in aqueous media. The stability constants of GdL1 and GdL2 are comparable, whereas a more marked difference is found in the kinetic inertness of the two complexes. The formation of the Eu(III) and Ce(III) complexes takes place via the formation of the protonated intermediates which can deprotonate and transform into the final complex through a OH-assisted pathway. GdL2 shows faster rates of acid catalysed decomplexation with respect to GdL1, which has a kinetic inertness comparable to GdDOTA. Nevertheless, GdL2 is one order of magnitude more inert than GdDO3A. A novel DOTAMAP-based bifunctional chelating ligand and its deoxycholic acid derivative (L5) were also synthesized. Since the coordinated water molecule in GdL2 is characterized by an exchange rate ca. two orders of magnitude greater than in GdL1, the relaxivity of the macromolecular derivatives of GdL5 should not be limited by the slow water exchange process. The relaxometric properties of the supramolecular adduct of GdL5 with human serum albumin (HSA) were investigated in aqueous solution by measuring the magnetic field dependence of the H-1 relaxivity which, at 20 MHz and 298 K, shows a 430% increase over that of the unbound GdL5 chelate. Thus, Gd(III) complexes with DOTAMAP macrocyclic ligands can represent good candidates for the development of stable and highly effective bioconjugate systems for molecular imaging applications

AAZTA-Like Ligands Bearing Phenolate Arms as Efficient Chelators for 68Ga Labelling in vitro and in vivo

: The introduction of a phenolate pendant arm in place of an acetate on AAZTA- and DATA-like ligands resulted in hepta- and hexadentate chelators able to form Ga(III) complexes with thermodynamic stability and kinetic inertness higher than that of other Ga(III) complexes based on the parent 6-amino-6-methylperhydro-1,4-diazepine scaffold. In particular, the heptadentate AAZ3A-endoHB with a phenolate arm on an endocyclic N-atom shows a logKGaL of 27.35 and a remarkable resistance to hydroxide coordination up to basic pH (pH>9). This behaviour allows to also improve the kinetic inertness of the complex showing a dissociation half-life (t1/2 ) at pH 7.4 of 76 h. Although also the hexadentate AAZ2A-exoHB chelator forms a stable (logKGaL =24.69) and inert (t1/2 =33 h at pH 7.4) Ga(III) complex, the 68 Ga labelling showed a better radiochemical yield with AAZ3A-endoHB, especially at room temperature. Thus, a bifunctional chelator of AAZ3A-endoHB was synthesized bearing an isothiocyanate group that was conjugated to the N-terminus of a c(RGD) peptide for integrin receptor targeting. Finally, the conjugate was successfully labelled with 68 Ga isotope, and the resulting radiotracer tested for its stability in human serum and then in vivo for targeting B16-F10 tumours with miniPET imaging

Nanotechnology-Based Targeted Drug Delivery: An Emerging Tool to Overcome Tuberculosis

The appearance and rapid spread of drug resistant strains of tuberculosis (TB), one of the deadliest infectious diseases, pose a serious threat to public health and increase the need for shorter, less toxic, and more effective therapies. Developing new drugs is difficult and often associated with side effects, so nanotechnology has emerged as a tool to improve current treatments and to rescue drugs having elevated toxicity or poor solubility. Due to their size and surface chemistry, antimicrobial-loaded nanocarriers are avidly taken up by macrophages, the main cells hostingMycobacterium tuberculosis. Macrophages are continuously recruited to infected areas, they can transport drugs with them, making passive targeting a good strategy for TB treatment. Active targeting (decorating surface of nanocarriers with ligands specific to receptors displayed by macrophages) further increases local drug concentration, and thus treatment efficacy. Although in in vivo studies, nanocarriers are often administered intravenously in order to avoid inaccurate dosage in animals, translation to humans requires more convenient routes like pulmonary or oral administration. This report highlights the importance and progress of pulmonary administration, passive and active targeting strategies toward bacteria reservoirs to overcome the challenges in TB treatment

Loci Memoriae Hungaricae

Miklós Takács: Preface - 7 ; 1. Theoretical reflections ; Zsófia O. Réti: Memory of Networks, Networks of Memory - 10 ; Gábor Palkó: The Phenomenon of “Linked Data” from a Media Archaeological Perspective - 23 ; 2. Digital Memory in Everyday Life ; Norbert Krek: Lieux de Mémoire and Video Games: Mnemonic Representations of the Second World War in First Person Shooter Games of the Early Twenty-first Century - 32 ; Antti Vallius: Landscapes of Belonging: Visual Memories in the Digital Age - 43 ; László Z. Karvalics: Defining Two Types of Cultural “Micro-heritage”: Objects, Knowledge Dimensions and a Quest for Novel Memory Institutions - 58 ; 3. New Media for Old Ideologies Tuija Saresma: Circulating the Origin Myth of Western Civilization – The Racial Imagery of the ‘Men of the North’ as an Imaginary Heritage in White Supremacist Blogs - 68 ; Klára Sándor: Versions of Folk History Representing Group Identities: The Battle for the Masternarrative - 82 ; 4. Rethinking Hungarian Collective Memory Katalin Bódi: Image and Imagination: The Changing Role of Art from the Nineteenth Century to the Present in Hungarian National Memory - 92 ; Zsófia Fellegi: Digital Philology on the Semantic Web: Publishing Hungarian Avant-garde Magazines - 105 ; Norbert Baranyai: Cult, Gossip, Memory—Aspects of Mediating Culture in Krisztián Nyáry’s Portraits of Writers in Facebook Posts - 117 ; Notes on Contributors - 127 ; Index - 13

Which mechanism underlies the water-like anomalies in core-softened potentials?

Using molecular dynamics simulations we investigate the thermodynamic of particles interacting with a continuous and a discrete versions of a core-softened (CS) intermolecular potential composed by a repulsive shoulder. Dynamic and structural properties are also analyzed by the simulations. We show that in the continuous version of the CS potential the density at constant pressure has a maximum for a certain temperature. Similarly the diffusion constant, $D$, at a constant temperature has a maximum at a density $\rho_{\mathrm{max}}$ and a minimum at a density $\rho_{\mathrm{min}}<\rho_{\mathrm{max}}$, and structural properties are also anomalous. For the discrete CS potential none of these anomalies are observed. The absence of anomalies in the discrete case and its presence in the continuous CS potential are discussed in the framework of the excess entropy.Comment: 8 page