82 research outputs found
The impact of alkyl chain purity on lipid based nucleic acid delivery systems – is the utilization of lipid components with technical grade justified?
The physicochemical properties and transfection efficacies of two samples of a cationic lipid have been investigated and compared in 2D (monolayers at the air/liquid interface) and 3D (aqueous bulk dispersions) model systems using different techniques. The samples differ only in their chain composition due to the purity of the oleylamine (chain precursor). Lipid 8 (using the oleylamine of technical grade for cost-efficient synthesis) shows lateral phase separation in the Langmuir layers. However, the amount of attached DNA, determined by IRRAS, is for both samples the same. In 3D systems, lipid 8 p forms cubic phases, which disappear after addition of DNA. At physiological temperatures, both lipids (alone and in mixture with cholesterol) assemble to lamellar aggregates and exhibit comparable DNA delivery efficiency. This study demonstrates that non-lamellar structures are not compulsory for high transfection rates. The results legitimate the utilization of oleyl chains of technical grade in the synthesis of cationic transfection lipid
Lamellar versus micellar structures-aggregation behavior of a three-chain cationic lipid designed for nonviral polynucleotide transfer
The directional observation of highly dynamic membrane tubule formation induced by engulfed liposomes
Highly dynamic tubular structures in cells are responsible for exchanges between organelles. Compared with bacterial invasion, the most affordable and least toxic lipids were found in this study to be gentle and safe exogenous stimuli for the triggering of membrane tubules. A specific lipid system was internalized by NIH3T3 cells. Following cellular uptake, the constructed liposomes traveled towards the nucleus in aggregations and were gradually distributed into moving vesicles and tubules in the cytosol. The triggered tubules proceeded, retreated or fluctuated along the cytoskeleton and were highly dynamic, moving quickly (up to several microns per second), and breaking and fusing frequently. These elongated tubules could also fuse with one another, giving rise to polygonal membrane networks. These lipid systems, with the novel property of accelerating intracellular transport, provide a new paradigm for investigating cellular dynamics
Deformation analysis of a metropolis from C- to X-band PSI: proof-of-concept with Cosmo-Skymed over Rome, Italy
Stability of monuments and subsidence of residential
quarters in Rome (Italy) are depicted based on geospatial
analysis of more than 310,000 Persistent Scatterers (PS)
obtained from Stanford Method for Persistent Scatterers
(StaMPS) processing of 32 COSMO-SkyMed 3m-resolution
HH StripMap ascending mode scenes acquired between 21
March 2011 and 10 June 2013. COSMO-SkyMed PS
densities and associated displacement velocities are
compared with almost 20 years of historical C-band ERS-
1/2, ENVISAT and RADARSAT-1/2 imagery. Accounting
for differences in image processing algorithms and satellite
acquisition geometries, we assess the feasibility of ground
motion monitoring in big cities and metropolitan areas by
coupling newly acquired and legacy SAR in full time series.
Limitations and operational benefits of the transition from
medium resolution C-band to high resolution X-band PS
data are discussed, alongside the potential impact on the
management of expanding urban environments
Experimental archaeology: Investigation on the copper-aluminum- silicon-oxygen system
The behavior of the Cu-Al-Si-O system was investigated in the temperature range of 800 degrees-1150 degreesC. X-ray diffraction, infrared spectroscopy, diffusive reflectance, and electron microscopy were applied to obtain information about the influence of sintering, crystallization, and chemical reaction, each of which determines the color of the material. Definition of the artificial term "engobe," opposite to the term "glaze," was possible using copper(II) oxide (CuO) as its indicator. The detected chemical processes render possible explanations about the traditional way of ceramic painting during the 16th century and support the knowledge transfer from the viewpoint of history and that of natural science, as attempted by "archaeometry.
Copper: morphology and selective partial oxidation
Kupfer als Katalysator für selektive Partialoxidationsreaktionen findet verbreitet Anwendung in wichtigen Prozessen der industriellen Chemie. Dabei sind besonders die Oxidation von Glycol an Kupfermetall und die Methanolsynthese an dem System Cu-Al-Zn-O zu erwähnen. Trotz dieser großen Bedeutung ist über das Redoxverhalten von Kupfer im für katalytische Reaktionen wichtigen Temperaturbereich von 25°C bis 800°C in Detail nur wenig bekannt und ist daher Gegenstand aktueller Forschung[1]
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