In-line hologram segmentation for volumetric samples.

We propose a fast, noniterative method to segment an in-line hologram of a volumetric sample into in-line subholograms according to its constituent objects. In contrast to the phase retrieval or twin image elimination algorithms, we do not aim or require to reconstruct the complex wave field of all the objects, which would be a more complex task, but only provide a good estimate about the contribution of the particular objects to the original hologram quickly. The introduced hologram segmentation algorithm exploits the special inner structure of the in-line holograms and applies only the estimated supports and reconstruction distances of the corresponding objects as parameters. The performance of the proposed method is demonstrated and analyzed experimentally both on synthetic and measured holograms. We discussed how the proposed algorithm can be efficiently applied for object reconstruction and phase retrieval tasks.

The Relationship between Online and Offline Information-Seeking Behaviors for Healthy Nutrition.

In addition to preserving their health, young people can also play a role in providing information to wider society. Nutrition habits that have developed over the years at college have an impact on the foundation of a lifelong lifestyle. Our aim was to identify university students' online and offline information-seeking attitudes related to healthy nutrition and create a new theoretical concept. Participants were university students (n = 612), and the self-administered, paper-based questionnaires were sent out to nine Hungarian universities. Both descriptive and multivariate statistical procedures were used in the analysis. Online and offline information sources were categorized. In relation to university students' information-seeking competence, the component of electronic health literacy was determined. In analyzing attitudes, the components of acceptance of, incentive for, and rejection of or ambivalence towards healthy nutrition were identified. The information-seeking categories related to the stages of university students' conscious transition to healthy nutrition were also identified. University students' competences related to electronic health literacy are essentially favorable. This target group accepts healthy nutrition and tries to recommend it to others, too. However, a rejecting or ambivalent attitude could also be identified. Online and offline sources of information accompany university students' transition of the relevant stages of changes. The theoretical concept that we developed can contribute to bridging gaps in the interrelatedness of diverse information sources and healthy nutrition.

Intranasal delivery of human beta-amyloid peptide in rats: effective brain targeting.

(1) Intranasal administration is a non-invasive and effective way for the delivery of drugs to brain that circumvents the blood-brain barrier. The aims of the study were to test a nasal delivery system for human beta-amyloid (A beta) peptides, to measure the delivery of the peptides to brain regions, and to test their biological activity in rats. (2) A beta(1-42), in the form of a mixture of oligomers, protofibrils, and fibrils was dissolved in a nasal formulation containing hydrophobic, hydrophylic, and mucoadhesive components. The peptide solution was administered intranasally to rats as a single dose or in repeated doses. (3) Nasally injected A beta labeled with the blue fluorescent dye amino-methyl coumarinyl acetic acid (AMCA) could be detected by fluorescent microscopy in the olfactory bulb and frontal cortex. The concentration of the peptide was quantified by fluorescent spectroscopy, and a significant amount of AMCA-A beta peptide could be detected in the olfactory bulb. Unlabeled A beta also reached the olfactory bulb and frontal cortex of rats as evidenced by intense immunostaining. (4) In behavioral experiments, nasal A beta treatment did not affect anxiety levels (open-field test) and short-term memory (Y-maze test), but significantly impaired long-term spatial memory in the Morris water maze. The treatments did not result in A beta immunization. (5) The tested intranasal delivery system could successfully target a bioactive peptide into the central nervous system and provides a basis for developing a non-invasive and cost effective, new model to study amyloid-induced dysfunctions in the brain.

[Determination of the gelatinization temperature of starches via thermoanalytical and rheological methods]. / Keményítok gélesedési homérsékletenek meghatározása termoanalitikai es reológiai módszerekkel.

This work provides a short review concerning the measuring techniques frequently applied to characterize the gelatinization behaviour of starches. The aim of the experiments was to determine the gelatinization temperatures of maize (A-type) and potato (B-type) starches via isothermal microcalorimetry and rheological methods (rotational viscosimetry and dynamic oscillatory testing). A significant difference was observed between the gelatinization temperatures of the aqueous starch suspensions, which can be attributed to the structural differences between A-type and B-type starches. Comparison of the applied measuring methods revealed a close correlation between the experimental data obtained by isothermal microcalorimetry and oscillatory testing, while rotational viscosimetry overestimated the gelatinization temperature. Additionally dynamic oscillatory tests provided valuable information not only on the gelatinization point, but also on the pasting temperature of the starch suspensions.

[Investigation of the structure of macromoleculare gels II: analysis of viscosity curves]. / Makromolekulás gélek szerkezetének vizsgálata II. A viszkozitásgörbék elemzése.

Viscosity curves of gels from homo-and copolymers in aqueous medium reviewed in our previous paper were studied. Viscosity vs. rate of shear, and viscosity vs. shearing time were analysed. The viscosity curves can be described with multiplicative functions and the slope of these functions characterizes the orientation ability of polymer molecule-chains under shear. On the base of viscosity vs. shearing time functions the network formed from polymers can be classified into energetic structure, topologic one and/or friction one. It was also established, that the aqueous polymer network structures studied do not thixotropic systems.

Fast 3D Imaging of Spine, Dendritic, and Neuronal Assemblies in Behaving Animals.

Understanding neural computation requires methods such as 3D acousto-optical (AO) scanning that can simultaneously read out neural activity on both the somatic and dendritic scales. AO point scanning can increase measurement speed and signal-to-noise ratio (SNR) by several orders of magnitude, but high optical resolution requires long point-to-point switching time, which limits imaging capability. Here we present a novel technology, 3D DRIFT AO scanning, which can extend each scanning point to small 3D lines, surfaces, or volume elements for flexible and fast imaging of complex structures simultaneously in multiple locations. Our method was demonstrated by fast 3D recording of over 150 dendritic spines with 3D lines, over 100 somata with squares and cubes, or multiple spiny dendritic segments with surface and volume elements, including in behaving animals. Finally, a 4-fold improvement in total excitation efficiency resulted in about 500 × 500 × 650 µm scanning volume with genetically encoded calcium indicators (GECIs).

[Investigation of structure of macromoleculare gels, I. Analysis of flow curves]. / Makromolekulás gélek szerkezetének vizsgálata I. A folyásgörbék elemzése.

Six polymers with different structure were investigated. The polymers studied were as follows: methylcellulose, hydroxyethylcellulose, carboxymethylcellulose sodium, polyacrylate sodium-polyacrylamid copolymer (Hostacerin PN 73), poly(vinylpyrrolidone)-poly(vinylacetate) copolymer (Kollidon VA 64) and poly(ethylenoxide)-poly(propylenoxide) blockpolymer. Physical networks from polymers in aqueous media were prepared. The flow curves of these systems were determined. Polynoms, multiplicative functions and linear ones were fitted to the flow curves. The close packing was characterised by correlation coefficient. Physical content of function constants was delineated. Practically the constants expressing the binding forces has a great importance. It was established, that the binding forces in cellulose derivates gels and that of acrylic acid-acrylamide polymer gels are similar. Other structure binding forces act in the poly(ethylenoxide)-poly(propylenoxide) block-copolymer systems. The difference are well demonstrated by the constants values of functions.

Sodium hyaluronate as a mucoadhesive component in nasal formulation enhances delivery of molecules to brain tissue.

Intranasal administration of molecules has been investigated as a non-invasive way for delivery of drugs to the brain in the last decade. Circumvention of both the blood-brain barrier and the first-pass elimination by the liver and gastrointestinal tract is considered as the main advantages of this method. Because of the rapid mucociliary clearance in the nasal cavity, bioadhesive formulations are needed for effective targeting. Our goal was to develop a formulation containing sodium hyaluronate, a well-known mucoadhesive molecule, in combination with a non-ionic surfactant to enhance the delivery of hydrophilic compounds to the brain via the olfactory route. Fluorescein isothiocyanate-labeled 4 kDa dextran (FD-4), used as a test molecule, was administered nasally in different formulations to Wistar rats, and detected in brain areas by fluorescent spectrophotometry. Hyaluronan increased the viscosity of the vehicles and slowed down the in vitro release of FD-4. Significantly higher FD-4 transport could be measured in the majority of brain areas examined, including olfactory bulb, frontal and parietal cortex, hippocampus, cerebellum, midbrain and pons, when the vehicle contained hyaluronan in combination with absorption enhancer. The highest concentrations of FD-4 could be detected in the olfactory bulbs, frontal and parietal cortex 4h after nasal administration in the mucoadhesive formulation. Intravenous administration of a hundred times higher dose of FD-4 resulted in a lower brain penetration as compared to nasal formulations. Morphological examination of the olfactory system revealed no toxicity of the vehicles. Hyaluronan, a non-toxic biomolecule used as a mucoadhesive in a nasal formulation, increased the brain penetration of a hydrophilic compound, the size of a peptide, via the nasal route.

Construction of a Linux based chemical and biological information system.

A chemical and biological information system with a Web-based easy-to-use interface and corresponding databases has been developed. The constructed system incorporates all chemical, numerical and textual data related to the chemical compounds, including numerical biological screen results. Users can search the database by traditional textual/numerical and/or substructure or similarity queries through the web interface. To build our chemical database management system, we utilized existing IT components such as ORACLE or Tripos SYBYL for database management and Zope application server for the web interface. We chose Linux as the main platform, however, almost every component can be used under various operating systems.