Reconstruction of hv-Convex Sets by Their Coordinate X-Ray Functions

Gardner and Kiderlen (Adv. Math. 214:323–343, 2007) presented an algorithm for reconstructing convex bodies from noisy X-ray measurements with a full proof of convergence in 2007. We would like to present some new steps into the direction of reconstructing not necessarily convex bodies by the help of the continuity properties of so-called generalized conic functions. Such a function measures the average taxicab distance of the points from a given compact set \(K\subset \mathbb {R}^{N}\) by integration. The basic result (Vincze and Nagy in J. Approx. Theory 164:371–390, 2012) is that the generalized conic function associated to a compact planar set determines the coordinate X-rays and vice versa. Vincze and Nagy (Submitted to Aequationes Math., 2014) proved continuity properties of the mapping which sends connected compact hv-convex sets having the same axis parallel bounding box to the associated generalized conic functions. We use these results to present an algorithm for the reconstruction of compact connected hv-convex planar bodies given by their coordinate X-rays. The basic method is varied with the quota system scheme. Greedy and anti-greedy versions are also presented with examples.     

Analysis of a small agricultural watershed using remote sensing techniques

Salinization of land and sweet water is an increasing problem worldwide. In the Carpathian Basin, particularly in arid and semi‐arid regions, irrigation is a contributing factor to the secondary salinization problems, one of the major problems affecting soils in Hungary. Conventional broadband sensors such as SPOT, Landsat MSS, and Landsat ETM+ are not suitable for mapping soil properties, because their bandwidth of 100–200 mm cannot resolve diagnostic spectral features of terrestrial materials. Analytical techniques, developed for analysis of broadband spectral data, are incapable of taking advantage of the full range of information present in hyperspectral remote sensing imagery. In our pilot project in Tedej farm in the Great Plain Region, Hungary, the DAIS sensor was used to assess salinity risk, covering the spectral range from the visible to the thermal infrared wavelengths at 5 m spatial resolution, and other major indicators of soil salinization (NDVI, SAVI, canopy cover) were quantified with advanced remote sensing techniques using the TETRACAM ADC agricultural multispectral camera which offers red/green and NIR imaging at megapixel resolution. As a result, prominent absorption bands around 1450 nm and 1950 nm wavelength in most soil spectra are attributed to water and hydroxyl ions. Occasional weaker absorption bands caused by water also occur at 970, 1200, and 1700 nm. Absorption features near the 400 nm wavelength for all samples are also noticeable. Absorption bands at 1800 and 2300 nm are attributed to gypsum, while strong absorption features near 2350 nm are assigned to calcite (CaCo₃). Saline soils exhibited significantly higher reflectance values all throughout the 325–2500 nm wavelengths of the spectrum. Soils with a high amount of soluble salts gave a higher average reflectance than soils with a low salt content. In the project, an ADC camera‐based real‐time integrated system was developed to take advantage of more specialized spectral information and to provide even more accurate and useful data directly from the field. The results revealed that the NDVI and SAVI index and the canopy cover mapping taken with multispectral cameras can be useful as an indirect marker and help for detecting salinization. However, we did not find a strong correlation between NDVI and soil salinity. This is probably because the detection and assessment of lower levels of salinity are difficult, mainly owing to the nature of the remotely sensed images; with such images, it is not possible to obtain information on the third dimension of the 3‐D soil body. Also, the impact of salinity on electromagnetic properties needs to be explored further to understand how it can be derived indirectly from remotely sensed information. With the rapid validation of remotely sensed hyperspectral data, the decision in the future, with the best trade‐off between irrigation and sustainable land use made by agricultural specialists in this region, can be more environmentally sound and more accurate using the results from the pilot.     

Automated Technology for Performing Flow-Chemistry at Elevated Temperature and Pressure

Over the past few years, a series of novel microfluidic-based instruments were developed by ThalesNano, Inc. to carry out dangerous and difficult to perform chemical reactions in a safe and fast manner, resulting in superior performance to what commercial batch reactors could provide. Importance of microfluidic devices is continuously raising, as seen there are more and more publications, applications and devices in this field expanding the borders of chemistry. Furthermore, as one of the main advantages for pharmaceutical applications, these new revolutionary reactors allow the fast, on-the-fly mode optimization of different heterogeneous reactions in a high-throughput fashion. The heart of the reactor systems is the actual reactor bed, called the CatCart system. CatCarts allow easy handling of heterogeneous catalyst or immobilized reagents without further purification of products. In addition, the shoe-box size of these reactors makes them available from laboratories to industrial applications.     

Motivations, Design and Business Models of Wireless Community Networks

In this paper we provide an integrated presentation of applications, technologies and business models for wireless community network together with design considerations and examples. An overview is given of the state-of-the-affairs of wireless community networks. Driving forces and stakeholders of the projects and the applications and services will be presented for some carefully selected cases. We suggest a design methodology and illustrate its application to an ongoing digital city project in Hungary. Relevant business models are also analyzed.     

Fundamentals of capillary electrochromatography: migration behavior of ionized sample components

The mechanism of separating charged species by capillary electrochromatography (CEC) was modeled with the conditions of ideal/linear chromatography by using a simple random walk. The most novel aspect of the work rests with the assumption that in sufficiently high electric field ionized sample components can also migrate in the adsorbed state on the ionized surface of the stationary phase. This feature of CEC leads to the introduction of three dimensionless parameters: alpha, reduced mobility of a sample component with the electrosmotic mobility as the reference; beta, the CEC retention factor; and gamma, the ratio of the electrophoretic migration velocity and the velocity of surface electrodiffusion. Since the interplay of retentive and electrophoretic forces determines the overall migration velocity, the separation mechanism in CEC is governed by the relative importance of the above parameters. The model predicts conditions under which the features of the CEC system engender migration behavior that manifests itself in a relatively narrow elution window and in a gradient like elution pattern in the separation of peptides and proteins by using pro forma isocratic CEC. It is believed that such elution patterns, which resemble those obtained by the use of external gradient of the eluent, are brought about by the formation of an internal gradient in the CEC system that gave rise to concomitant peak compression. The peculiarities of CEC are discussed in the three operational modalities of the technique: co-current, countercurrent, and co-counter CEC. The results suggest that CEC, which is often called "liquid chromatography on electrophoretic platform" is an analytical tool with great potential in the separation of peptides and proteins.     

Response of liver cells to insulin at 1 week postnatal as influenced by a prior action of the same hormone at the time of birth (hormonal imprinting): an electron microscopic study

Liver cells of rats given a single insulin dose at birth (imprinted) do not alter from the controls at 1 week postnatal. When hormone treatment occurs at 1 week postnatal without any prior administration of it, an increase in glycogen and lipid with nuclear deposition of the latter can be seen. The cell surface displays a dense layer, and increased micropinocytosis is accompanied by an increase in the number of coated pits and vesicles. Liver cells of imprinted animals treated repeatedly at 1 week postnatal have much more glycogen and lipid, and more prominent endoplasmic reticulum but a less mature Golgi apparatus. The dense substance of the cell surface is missing and the signs of endocytosis are rarely seen. These alterations indicate the influence of imprinting on hormone binding and possibly on the next steps after interaction in the cell.     

Application of an objective method for localizing bilateral cortical FDG PET abnormalities to guide the resection of epileptic foci

PURPOSE: In order to improve the objective localization of bilateral cortical abnormalities in positron emission tomography (PET) image volumes, we developed a new three-dimensional image processing technique. The accuracy of this approach with respect to invasive subdural electroencephalography (EEG) data was assessed in a group of children with neocortical epilepsy. METHODS: Glucose PET image volumes were obtained from 12 epileptic children (mean age 5.2 +/- 4.3 years). Bilateral cortical areas of abnormal glucose metabolism were objectively determined using two conditional criteria assessed against a normal database. The normal database was derived from a group of 15 adult controls (mean age 27.6 years). The spatial relationship between seizure onset electrodes and PET abnormalities was assessed using a conventional receiver operating characteristic (ROC) analysis as well as using a newly defined spatial proximity index (SPI), which characterizes the association between adjacent, but not coincident, abnormalities. RESULTS: ROC analysis at the 2 standard deviation (SD) threshold, revealed an accuracy of 65% to detect seizure onset areas with a sensitivity of 64 +/- 17% and a specificity of 66 +/- 24%. Sensitivity decreased to 46 +/- 24% at the 3-SD threshold with a specificity of 80 +/- 21% (accuracy 75%). The average value for the SPI was determined as 3.82 +/- 1.65 which was 20% lower than the SPI value calculated using a simple in-plane two-dimensional asymmetry between homotopic cortical segments (4.52 +/- 3.82). CONCLUSION: The presented image processing technique improves localization of cortical abnormalities and provides valuable imaging clues for placement of subdural EEG grids prior to surgical resection.     

An application of the finite element method to maximum entropy tomographic image reconstruction

A new approach to maximum entropy tomographic image reconstruction is presented. It is shown that by using a finite-dimensional subspace, one can obtain an approximation to the solution of a maximum entropy optimization problem, set inL ₂ D. An example of an appropriate finite element subspace for a two-dimensional parallel beam projection geometry is examined. Particular attention is paid to the case where the x-ray projection data are sparse. In the current work, this means that the number of projections is small (in practice, perhaps only 5–20). A priori information in the form of known maximum and minimum densities of the materials being scanned is built into the model. A penalty function, added to the entropy term, is used to control the residual error in meeting the projection measurements. The power of the technique is illustrated by a sparse data reconstruction and the resulting image is compared to those obtained by a conventional method.     

Insulin treatment (hormonal imprinting) increases the insulin production of the unicellular tetrahymena long term. Is there a simultaneous formation of hormone receptor and hormone?

Insulin treatment of Tetrahymena pyriformis resulted in a long-lasting increase in the insulin content of the cells. After about 200 generations, insulin levels significantly higher than in the control were demonstrated by using a quantitative immunocytochemical method. Although the insulin content fluctuated from day to day, it was always higher in the insulin pre-treated (imprinted) cells than in the controls. The results emphasise the simultaneous stimulation of hormone and receptor formation by hormonal imprinting.     

Effects of the amino sugars, glucosamine, mannosamine, or the fluorinated derivative 2-deoxy-fluoroglucose on the phosphatidyl inositol and glycosyl phosphatidyl inositol systems of Tetrahymena

Sugar derivatives which have an inhibitory effect on glycosyl phosphatidyl inositol (GPI) synthesis in mammals, primarily prevented 32P incorporation in the unicellular Tetrahymena. Incorporation of 3H-mannose and 3H-inositol was induced by mannosamine. While there was a uniform effect of sugar analogues in mammals, they could not elicit totally similar effects in Tetrahymena. Analogues of sugar also affected synthesis in the phosphatidyl inositol (PI) system. Synthesis of GPI in Tetrahymena was different from that in mammals, but the metabolism of GPI and PI revealed similarities.