Search results for "Lene"
showing 10 items of 4480 documents
A fluorescence study of the loading and time stability of doxorubicin in sodium cholate/PEO-PPO-PEO triblock copolymer mixed micelles
2019
Abstract Hypothesis Doxorubicin hydrochloride (DX) is one of the most powerful anticancer agents though its clinical use is impaired by severe undesired side effects. DX encapsulation in nanocarrier systems has been introduced as a mean to reduce its toxicity. Micelles of the nonionic triblock copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) (PEO-PPO-PEO), are very promising carrier systems. The positive charge of DX confines the drug to the hydrophilic corona region of the micelles. The use of mixed micelles of PEO-PPO-PEO copolymers and a negatively charged bile salt should favour the solubilization of DX in the apolar core region of the micelles. Experiments We st…
Addition of Ethylene or Hydrogen to a Main-Group Metal Cluster under Mild Conditions
2015
Reaction of the tin cluster Sn8(Arinline image)4 (Arinline image=C6H2-2,6-(C6H3-2,4,6-Me3)2) with excess ethylene or dihydrogen at 25 °C/1 atmosphere yielded two new clusters that incorporated ethylene or hydrogen. The reaction with ethylene yielded Sn4(Arinline image)4(C2H2)5 that contained five ethylene moieties bridging four aryl substituted tin atoms and one tin–tin bond. Reaction with H2 produced a cyclic tin species of formula (Sn(H)Arinline image)4, which could also be synthesized by the reaction of {(Arinline image)Sn(μ-Cl)}2 with DIBAL-H. These reactions represent the first instances of direct reactions of isolable main-group clusters with ethylene or hydrogen under mild conditions…
Synthesis, characterization, and reactivity of heavier group 13 and 14 metallylenes and metalloid clusters : small molecule activation and more
2015
Influence of Calcium Carbonate Nanoparticles on the Soil Burial Degradation of Polybutyleneadipate-Co-Butylenetherephthalate Films.
2022
A polybutyleneadipate-co-butylenetherephthalate (PBAT) sample, commercially known as Ecoflex®, was processed via melt extrusion with CaCO3 nanoparticles coated with a hydrophobic coating. Blown films of PBAT and two composites with nanofiller (2% and 5%wt) were prepared and degradation tests in soil at 30 °C up to 180 days were carried out with weight loss measurements. Furthermore, biodegradation test according to ISO 14851 was carried out at 30 °C. The effect of CaCO3 on soil burial degradation was assessed by surface wettability and SEM. ATR-FTIR and XPS analyses highlighted chemical modifications induced by soil degradation. CaCO3 nanoparticles decreased surface wettability …
Sonication-Induced Modification of Carbon Nanotubes: Effect on the Rheological and Thermo-Oxidative Behaviour of Polymer-Based Nanocomposites.
2018
The aim of this work is the investigation of the effect of ultrasound treatment on the structural characteristics of carbon nanotubes (CNTs) and the consequent influence that the shortening induced by sonication exerts on the morphology, rheological behaviour and thermo-oxidative resistance of ultra-high molecular weight polyethylene (UHMWPE)-based nanocomposites. First, CNTs have been subjected to sonication for different time intervals and the performed spectroscopic and morphological analyses reveal that a dramatic decrease of the CNT's original length occurs with increased sonication time. The reduction of the initial length of CNTs strongly affects the nanocomposite rheological behavio…
A Theoretical and Experimental Investigation of the Spectroscopic Properties of a DNA-Intercalator Salphen-Type ZnIIComplex
2014
The photophysical and DNA-binding properties of the cationic zinc(II) complex of 5-triethylammonium methyl salicylidene ortho-phenylenediiminato (ZnL 2 + ) were investi- gated by a combination of experimental and theoretical methods. DFT calculations were performed on both the ground and the first excited states of ZnL 2 + and on its possi- ble mono- and dioxidation products, both in vacuo and in selected solvents mimicked by the polarizable continuum model. Comparison of the calculated absorption and fluores- cence transitions with the corresponding experimental data led to the conclusion that visible light induces a two-elec- tron photooxidation process located on the phenylenediimi- nato…
Realization of time-resolved two-vacuum-ultraviolet-photon ionization
2009
International audience; Ultrafast dynamics of excited molecules is studied through time-resolved two-vacuum-ultraviolet (vuv)- photon ionization using a nonlinear volume autocorrelator unit. The two-vuv-photon process is induced by the intense fifth harmonic radiation of a femtosecond Ti:sapphire laser. In a proof-of-principle experiment, ultrafast dynamics of excited ethylene and oxygen molecules are investigated. Molecular decay times are deduced by comparing the experimental data with the results of a numerical model that accounts for the spatial and temporal characteristics of the harmonic field. The present experiments pave a convenient way for time domain investigations in the vuv-xuv s…
Tīklenes attēlu iegūšana ar dažādiem apgaismojumiem
2015
Maģistra darbs ir uzrakstīts latviešu un angļu valodās, datorsalikumā uz 48 lapām. Tas satur 34 attēlus, 6 tabulas, 37 atsauces uz literatūras avotiem. Mērķis: izveidot spektrāli maināmu gaismas avotu, kas uzlabotu diabēta radītu tīklenes bojājumu un citu tīklenes struktūru kompjūter-diagnostiku. Metode: Spektrāli maināms gaismas avots, kas ir balstīts uz digitālās mikrospoguļu ierīces (DMD) un modificētas fundus kameras, kas komplektēti ar monohromatisku kameru tīklenes attēlu iegūšanai. Tīklenes attēli uzņemti, gan no vesela pētījuma dalībnieka, gan diabēta pacientiem. Secinājumi: Ar spektrāli maināmu gaismas avotu ar optimizētiem apgaismojumiem var uzņemt uzlabota kontrasta tīklenes stru…
Multi-functional Stabilizers-functionalized Carbon Nanotubes for advanced Ultra-High Molecular Weight Polyethylene-based Nanocomposites
2015
Stabilizing molecules, such as hindered phenols (both synthetic and naturally occurring), polyphenols and hindered amine light stabilizers, were covalently linked or physically absorbed onto outer surface of multi-walled carbon nanotubes (CNTs) and the obtained multi-functional fillers (Stab-f-CNTs) were dispersed in Ultra High Molecular Weight Polyethylene (UHMWPE) aiming at obtaining advanced nanocomposites with enhanced thermo- and/or photo-oxidative stability, electrical and mechanical properties. The chemical grafting or physical absorption of stabilizing molecules is confirmed by spectroscopic, spectrometric and thermo-gravimetric analyses, and the influence of the multi-functional na…
The weathering test of polypropylene composites
2000
Polipropylen "Malen P" czysty (a), kompozyty na jego podstawie napełniane (20% mas.) kredą lub talkiem (b) oraz produkty te stabilizowane dodatkowo stabilizatorem UV typu HALS ("Tinuvin 791") (c) poddano badaniom laboratoryjnego starzenia atmosferycznego. Badane próbki poddawano działaniu promieniowania ultrafioletowego w dawkach do 950 MJ/m2, w zaprogramowanych warunkach temperatury, wilgotności oraz nadeszczania. Postęp fotodegradacji polimeru śledzono na podstawie zmian ciężaru cząsteczkowego, jego rozkładu (GPC) oraz wybranych właściwości mechanicznych (wydłużenia względnego, naprężenia zrywającego, udarności z karbem). Określono również odporność próbek badanych białych kompozytów na z…