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

Soziale ungleichheit von lesekompetenzen: Eine Matching-Analyse im Längsschnitt mit Querschnittsdaten von PIRLS 2001 und PISA 2000

Zusammenfassung: In Anlehnung an das strukturell-individualistische Handlungsmodell von Boudon werden für Deutschland kausale Effekte von individuellen Lernvoraussetzungen, Ressourcen des Elternhauses, sozial selektiven Bildungsübergängen sowie Lehr-und Lernbedingungen in Schulen auf die Entwicklung von Lesekompetenzen und ihre Streuung zwischen Sozialschichten untersucht. Hierbei wird zum einen der Frage nachgegangen, ob neben den Herkunftseffekten die Selektion von Grundschulkindern in die weiterführenden Schulen in der Sekundarstufe I zur allgemeinen Verschlechterung der mittleren Lesekompetenzen beitragen. Zum anderen wird gefragt, ob der sozial selektive Bildungsübergang von der Primar-in die Sekundarstufe eine bedeutsame Ursache für einen Anstieg in der ungleichen Verteilung von Leseleistungen zwischen den Sozialschichten ist. Weil es nicht möglich ist, solche Ursache-Wirkungszusammenhänge mit komparativ-statischen Querschnittsdaten wie PIRLS oder PISA empirisch zu isolieren, konstruieren wir anhand von Daten der beiden Studien PISA-E 2000 und PIRLS 2001 über das Verfahren des "pairwise matching” Quasi-Längsschnittdaten mit drei Beobachtungszeitpunkten (Leseleistung bei Einschulung, Leseleistung im Alter von 9 bis 10 Jahren und Leseleistung im Alter von 15 Jahren). Die empirischen Befunde belegen zusätzlich zu den Herkunftseinflüssen die Rolle sozial selektiver Bildungsübergänge und damit die Sortier-und Selektionsleistungen des deutschen Bildungssystems. Es wird gezeigt, dass, neben individuellen Lernvoraussetzungen und Ressourcen des Elternhauses, die soziale Selektivität der Bildungsübergänge und damit auch sozial differentielle Lernbedingungen signifikant zur Erklärung der Entwicklung individueller Leseleistung und sozialen Disparität von Lesekompetenzen beitrage

Tresylated PEG-sterols for coupling of proteins to preformed plain or PEGylated liposomes

AbstractA simple and inexpensive method for functionalization of preformed liposomes is presented. Soy sterol–PEG1300 ethers are activated by tresylation at the end of the PEG chain. Coupling of bovine serum albumin as an amino group containing model ligand to the activated lipids can be performed at pH 8.4 with high efficiency. At room temperature, the mixture of sterol–PEG and sterol–PEG–protein inserts rapidly into the outer liposome monolayer with high efficiency (>100 μg protein/μmol total lipid). This method of post-functionalization is shown to be effective with fluid or rigid and plain or pre-PEGylated liposomes (EPC/Chol, 7:3; HSPC/Chol 2:1, and EPC/Chol/MPEG2000–DSPE 2:1:0.16 molar ratios). The release of entrapped calcein upon the insertion of 7.5 mol% of the functionalized sterols is lower than 4%. Incubation of post-functionalized liposomes with serum for 20 h at 37 °C shows stable protein attachment at the liposome surface

Multistage s-t Path: Confronting Similarity with Dissimilarity in Temporal Graphs

Addressing a quest by Gupta et al. [ICALP\u2714], we provide a first, comprehensive study of finding a short s-t path in the multistage graph model, referred to as the Multistage s-t Path problem. Herein, given a sequence of graphs over the same vertex set but changing edge sets, the task is to find short s-t paths in each graph ("snapshot") such that in the found path sequence the consecutive s-t paths are "similar". We measure similarity by the size of the symmetric difference of either the vertex set (vertex-similarity) or the edge set (edge-similarity) of any two consecutive paths. We prove that these two variants of Multistage s-t Path are already NP-hard for an input sequence of only two graphs and maximum vertex degree four. Motivated by this fact and natural applications of this scenario e.g. in traffic route planning, we perform a parameterized complexity analysis. Among other results, for both variants, vertex- and edge-similarity, we prove parameterized hardness (W[1]-hardness) regarding the parameter path length (solution size) for both variants, vertex- and edge-similarity. As a further conceptual study, we then modify the multistage model by asking for dissimilar consecutive paths. One of our main technical results (employing so-called representative sets known from non-temporal settings) is that dissimilarity allows for fixed-parameter tractability for the parameter solution size, contrasting the W[1]-hardness of the corresponding similarity case. We also provide partially positive results concerning efficient and effective data reduction (kernelization)

Colonisation success of introduced oysters is driven by wave-related exposure

The Pacific oyster, Magallana gigas, is an extremely successful invader with established populations in marine and estuarine habitats almost all over the world. Ecological implications of the introduction of this species to indigenous communities are well documented. However, the processes by which this species successfully establishes in a recipient community is still insufficiently understood. The early detection of the oyster at the island of Helgoland (North Sea) provided the ideal opportunity to investigate whether physical mechanisms, such as wave exposure, influence their successful colonisation. We hypothesized that oyster colonisation benefits from wave-protected conditions. For this purpose, we evaluated colonisation success of M. gigas among wave-protected sites and wave-exposed sites along the island’s pier system. The densities of M. gigas were significantly higher at wave-protected sites than at wave-exposed sites, and the frequency distributions of oyster lengths indicated better growth and higher survival rates in the harbours. This higher colonisation success at wave-protected sites may be explained by the relative retention time of water masses in the harbours, probably resulting in both reduced larval drift and lower energy demands for secretion formation (i.e. firmer binding to the substrate). The fact that the density of M. gigas can vary greatly on small spatial scales depending on exposure corroborates a multiple exposure sampling approach to monitor oyster populations in order to avoid potential overestimations of population sizes in given areas

Effects of solar evolution on finite acquisition time of Fabry-Perot-Interferometers in high resolution solar physics

The imaging spectro-polarimeter VTF (Visible Tunable Filter) will be operated at the Daniel K. Inouye Solar Telescope (DKIST). Due to its capability of resolving dynamic fine structure of smaller than 0.05'', the finite acquisition time of typically 11 s affects the measurement process and potentially causes errors in deduced physical parameters. We estimate those errors and investigate ways of minimising them. We mimic the solar surface using a magneto-hydrodynamic simulation with a spatially averaged vertical field strength of 200 G. We simulate the measurement process scanning through successive wavelength points with a temporal cadence of 1 s. We synthesise FeI 617.3 nm. Besides the classical composition of the line profile, we introduce a novel method in which the intensity in each wavelength point is normalised using the simultaneous continuum intensity. Milne-Eddington inversions are used to infer the line-of-sight velocity, v(los), and the vertical (longitudinal) component of the magnetic field, B(los). We quantify systematic errors, defining the temporal average of the simulation during the measurement as the truth. We find that with the classical composition of the line profiles, errors exceed the sensitivity for v(los) and in filigree regions also for B(los). The novel method that includes normalisation reduces the measurement errors in all cases. Spatial binning without reducing the acquisition time decreases the measurement error slightly. The evolutionary time-scale in inter-granular lanes, in particular in areas with magnetic features (filigree), is shorter than the time-scale within granules. Hence less accumulations could be used for strong magnetic field in inter-granular lanes and more accumulations could be used for the weak granular magnetic fields. As a key result, we suggest to include the novel method of normalisation in corresponding data pipelines.Comment: 11 pages, 11 figures, accepted for publication in A&

Mapping and modeling eelgrass Zostera marina distribution in the western Baltic Sea

In the northern hemisphere, eelgrass Zostera marina L. is the most important and widespread seagrass species. Despite its ecological importance, baseline data on eelgrass distribution and abundance are mostly absent, particularly in subtidal areas with relatively turbid waters. Here, we report a combined approach of vegetation mapping in the Baltic Sea coupled to a species distribution model (SDM). Eelgrass cover was mapped continuously in the summers of 2010 and 2011 with an underwater towed camera along ~400 km of seafloor. Eelgrass populated 80% of the study region and occurred at water depths between 0.6 and 7.6 m at sheltered to moderately exposed coasts. Mean patch length was 128.6 m but was higher at sheltered locations, with a maximum of >2000 m. The video observations (n = 7824) were used as empiric input to the SDMs. Using generalized additive models, 3 predictor variables (depth, wave exposure, and slope), which were selected based on Akaike’s information criterion, were sufficient to predict eelgrass presence/absence. Along with a very good overall discriminative ability (area under the receiver-operating characteristic curve ROC/AUC = 0.82), depth (as a proxy for light), wave exposure, and slope contributed 66, 29, and 5%, respectively, to the final model. The estimated total areal extent of eelgrass in the study region amounts to 140.5 km2 and comprises about 11.5% of all known Baltic seagrass beds. The present work is, to the best of our knowledge, the largest study undertaken to date on vegetation mapping and the first to assess distribution of eelgrass quantitatively in the western Baltic Sea