The Preparation of Liposomes Derived From Mixed Micelles of Lecithin Added by Sodium Cholate, Followed by Dialysing Using Hemoflow High Flux F60S

Liposomes are used for drug carriers meaning that drugs are incorporated in the membrane or the vesicle of the liposomes. In this study, liposomes were prepared from mixed micelles, consisting of phosphatidylcholine, without or with cholesterol and sodium cholate was added in several ratios namely 0.44; 0.55; 0.63; 0.70; 0.90 and 1.10. After the preparation, the sodium cholate has been removed by a dialysis membrane, using the Hemoflow High Flux, which is generally used for haemodialysis. The Hemoflow High Flux is a tool in an effort to obtain a simple, quick, effective method for removing sodium cholate in the process of preparing liposomes. The effectiveness of this tool was proved by the particle size of the liposome which was measured by the Malvern Particle Sizer. The particle size of the liposome consisting of phosphatidylcholine (PC) without cholesterol and with cholesterol was 63-68 nm at all ratios and approximately 125 nm at the ratio of 0.55; 0.63; 0.70, respectively. The particle size of the liposome tended to be smaller after dialyzing, although the concentration of lipids tended to increase. However, a large amount of buffer solution has to be used with this method

Net electrophilicity as computational route for the choice of favorable ionic liquids in nanoparticle production

In the last years, the potential of using ionic liquids (IL)s as an environment for nanoparticle (NP) synthesis has been demonstrated and in particular, triggering NP formation in ILs by electron irradiation has been reported as a very simple and clean route for NP production. Starting from the recent evidence for a correlation between an IL's capability to support NP production and the radiochemical instability of the IL's cation, we used conceptual Density Functional Theory (DFT) to provide a pre-screening of a set of different IL cations. The screened quantity is the net electrophilicity which we suggest as possible measure of this instability. Therefore, our work not only gives a measure for the likelihood of NP generation in different ILs, but it also provides a model which can further be extended and applied to obtain information about any other IL of interest. Moreover, our theoretical approach outlines a strategy which may reduce a lengthy experimental investigation for the identification of the most suitable IL for a particular reaction.Comment: 12 pages, 11 figures, 2 tables (including SI

Synthesis of hydrophilic and hydrophobic carbon quantum dots from waste of wine fermentation

Wine lees are one of the main residues formed in vast quantities during the fermentation of wine. While toxic when applied to plants and wetlands, it is a biodegradable material, and several alternatives have been proposed for its valorization as: dietary supplement in animal feed, source for various yeast extracts and bioconversion feedstock. The implementation of stricter environment protection regulations resulted in increasing costs for wineries as their treatment process constitutes an unavoidable and expensive step in wine production. We propose here an alternative method to reduce waste and add value to wine production by exploiting this rich carbon source and use it as a raw material for producing carbon quantum dots (CQDs). A complete synthetic pathway is discussed, comprising the carbonization of the starting material, the screening of the most suitable solvent for the extraction of CQDs from the carbonized mass and their hydrophobic or hydrophilic functionalization. CQDs synthesized with the reported procedure show a bright blue emission (λmax = 433 ± 13 nm) when irradiated at 366 nm, which is strongly shifted when the wavelength is increased (e.g. emission at around 515 nm when excited at 460 nm). Yields and luminescent properties of CQDs, obtained with two different methods, namely microwave and ultrasound-based extraction, are discussed and compared. This study shows how easy a residue can be converted into an added- value material, thus not only reducing waste and saving costs for the wine- manufacturing industry but also providing a reliable, affordable and sustainable source for valuable materials

Combined Theoretical and Experimental Study of the Moiré Dislocation Network at the SrTiO3-(La,Sr)(Al,Ta)O3 Interface.

Recently, a highly ordered Moiré dislocation lattice was identified at the interface between a SrTiO3 (STO) thin film and the (LaAlO3)0.3(Sr2TaAlO6)0.7 (LSAT) substrate. A fundamental understanding of the local ionic and electronic structures around the dislocation cores is crucial to further engineer the properties of these complex multifunctional heterostructures. Here, we combine experimental characterization via analytical scanning transmission electron microscopy with results of molecular dynamics and density functional theory calculations to gain insights into the structure and defect chemistry of these dislocation arrays. Our results show that these dislocations lead to undercoordinated Ta/Al cations at the dislocation core, where oxygen vacancies can easily be formed, further facilitated by the presence of cation vacancies. The reduced Ti3+ observed experimentally at the dislocations by electron energy-loss spectroscopy is a consequence of both the structure of the dislocation itself and of the electron doping due to oxygen vacancy formation. Finally, the experimentally observed Ti diffusion into the LSAT around the dislocation core occurs only together with cation vacancy formation in the LSAT or Ta diffusion into STO

Combined theoretical and experimental study of the Moir\'e dislocation network at the SrTiO3_3-(La,Sr)(Al,Ta)O3_3 interface

Recently a highly ordered Moir\'e dislocation lattice was identified at the interface between a \ce{SrTiO3} (STO) thin film and the (LaAlO$_3$)$_{0.3}$(Sr$_2$TaAlO$_6$)$_{0.7}$ (LSAT) substrate. A fundamental understanding of the local ionic and electronic structure around the dislocation cores is crucial to further engineer the properties of these complex multifunctional heterostructures. Here we combine experimental characterization via analytical scanning transmission electron microscopy with results of molecular dynamics and density functional theory calculations to gain insights into the structure and defect chemistry of these dislocation arrays. Our results show that these dislocations lead to undercoordinated Ta/Al cations at the dislocation core, where oxygen vacancies can easily be formed, further facilitated by the presence of cation vacancies. The reduced Ti$^{3+}$ observed experimentally at the dislocations by electron energy-loss spectroscopy are a consequence of both the structure of the dislocation itself, as well as of the electron-doping due to oxygen vacancy formation. Finally, the experimentally observed Ti diffusion into LSAT around the dislocation core occurs only together with cation-vacancy formation in LSAT or Ta diffusion into STO

Atomic Resolution Imaging with a sub-50 pm Electron Probe

Using a highly coherent focused electron probe in a 5th order aberration-corrected transmission electron microscope, we report on resolving a crystal spacing less than 50 pm. Based on the geometrical source size and residual coherent and incoherent axial lens aberrations, an electron probe is calculated, which is theoretically capable of resolving an ideal 47 pm spacing with 29percent contrast. Our experimental data show the 47 pm spacing of a Ge 114 crystal imaged with 11-18percent contrast at a 60-95percent confidence level, providing the first direct evidence for sub 50-pm resolution in ADF STEM imaging

Intergranular pore space evolution in MX80 bentonite during a long-term experiment

Focused ion beam nanotomography (FIB-nt) was applied to MX80 bentonite samples from the long-term Alternative Buffer Material (ABM) experiment in order to study the evolution of the intergranular pore space under similar condition that is supposed to prevail in repositories of nuclear waste. The applied high-resolution imaging method revealed the presence of two different types of pore filler. The first type is related to corrosion of iron and is represented by newly formed heavy minerals. Extensive formation of heavy minerals occurred only near the iron parts of the experimental set up. Based on comparison with other studies, the second filler type was interpreted as clay-gel that was likely formed during water uptake and swelling. A large fraction of the initial pore space was filled with such a clay gel. By attributing filled pores to the present open porosity, the initial intergranular porosity (radii > 10 nm) of the starting material was in the range of 4.3–4.6 vol.%, which was reduced to 10 nm), which yielded percolation thresholds with critical porosities ϕ in the range of 3–19 vol.%. Thus, the residual open porosity was far below the percolation threshold. The initial porosity of one sample was above the percolation threshold, but also in this material percolation was restricted to one spatial direction. This indicated anisotropy with respect to percolation. The formation of a clay-gel and heavy minerals led to a decrease in intergranular porosity, which in turn affected connectivity of the pore network. Using results from pore-network modelling in combination with percolation theory illustrates that a minor reduction of porosity led to a substantial decrease in pore connectivity. Depending on water saturation within the observed intergranular pore space, air permeability decreases exponentially over three to four orders of magnitude within a narrow porosity range of about 1 vol.%. Based on observations and calculations, gas transport along the intergranular pore space of MX80 bentonite from the ABM experiment is not considered as a possible scenario and can reasonably be excluded