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  • Author or Editor: A. Deák x
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The development of high performance insulating materials incorporating nanotechnologies has enabled considerable decrease in the effective thermal conductivity. Besides the use of conventional insulating materials, such as mineral fibers, the adoption of new nano-technological materials such as aerogel, vacuum insulation panels, graphite expanded polystyrene, is growing. In order to reduce the thermal conductivity of polystyrene insulation materials, during the manufacturing, nano/micro-sized graphite particles are added to the melt of the polystyrene grains. The mixing of graphite flakes into the polystyrene mould further reduces the lambda value, since graphite parts significantly reflect the radiant part of the thermal energy. In this study, laboratory tests carried out on graphite insulation materials are presented. Firstly, thermal conductivity results are described, and then sorption kinetic curves at high moisture content levels are shown. The moisture up-taking behaviour of the materials was investigated with a climatic chamber where the relative humidity was 90% at 293 K temperature. Finally, calorific values of the samples are presented after combusting in a bomb calorimeter.

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Authors: E. Kuzmann, M. Varsányi, L. Korecz, A. Vértes, T. Masumoto, F. Deák, Á. Kiss and L. Kiss

Abstract  

Neutron, and Mössbauer spectroscopy were used to study the possibility of cold nuclear fusion in Fe90Zr10 amorphous ribbon having high hydrogen absorbing ability. No significant changes in the neutron and in the spectra were found at deuterization performed electrochemically at different cathodic potentials. The observed differences between the Mössbauer spectra of samples deuterized in air and in nitrogen atmosphere can be explained by decrease of deuterium uptake as well as by a small heat effect due to reaction of hydrogen with oxygen dissolved in water in the case of electrolysis carried out in air.

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Abstract

Ureteric complications following renal transplantation are well known to cause significant morbidity and compromised graft survival. The necrosis of a major part of the ureter could be a highly detrimental situation, and hardly solvable complication, that poses great challenges. Herein we are presenting a case report to introduce a possible surgical solution following repeated ineffective radiological interventions, in a patient with ureteric necrosis that appeared 3 months after cadaveric kidney transplantation. We transplanted the right kidney to the right iliac fossa performing end-to-side vascular anastomoses and end-to-side uretero-ureterostomy. His clinical course was uneventful during 3 months, when he presented a mild borderline acute cellular rejection together with dilatation of the pyelon. Percutaneous nephrostomy was performed by interventional radiologist. During further radiologic interventions the stenosis was not permeable. We finally made up our minds for surgical solution. We found a totally necrotized graftureter. During a second operation we performed a right nephrectomy, transsecting the pyelon. After mobilization of the transplanted kidney approaching and identifying the pyelon, a large pyelopyelar anastomosis was performed with stenting. The postoperative follow-up showed excellent urine flow from the kidney to the bladder, then the TRD was removed. Surgery had to be considered only if minimally invasive procedures are infeasible or ineffective. A regimen of reconstructive methods are well-known, but all cases have to be evaluated individually. If the native kidneys can be removed, their pyelons and entire ureters should be used for reconstruction.

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Authors: Gy. Györe-Kis, K. Deák, A. Lugasi, A. Csúr-Vargaa and L. Helyes

A three years (2008, 2009, and 2011) open field experiment was conducted to study the effect of growing methods (organic and conventional) on the tomato yield components (Brix°, carbohydrate, organic acid, lycopene, and total polyphenols). Significantly higher Brix°, carbohydrate-, and lycopene content was found in conventional production. In spite of this, total phenolic content of tomato fruits was significantly higher in organic production. Our experiences show that it is probable, that the techniques used in the cultivation of organic crops — no artificial nutrients — could activate natural defence mechanisms in tomato plants, by increasing content of total polyphenol in the fruits.

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Authors: Veronika Kozma, Gy. Végső, P. Á. Deák, E. Hartmann, A. Németh, Sz. Török, R. Langer and A. Doros

Abstract

Kidney neoplasms can occur after kidney transplantation in low percentage. In this report we delineate a rare case of neoplasm in the transplanted kidney detected on screening ultrasonographic examination. Due to the intercalyceal location of the tumor percutaneous radiofrequency ablation was planned with continuous cooling the collecting system avoiding the thermal damage. To the best of our knowledge this method has never been reported applying in transplanted kidney. The two-month CT follow-up verified no residual tumor and the kidney function remained in normal range during this period. These facts imply that the method can be safely applied.

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We studied the early vegetation dynamics in former croplands (sunflower and cereal fields) sown with a low-diversity seed mixture (composed of 2 native grass species) in Egyek-Pusztakócs, Hortobágy National Park, East-Hungary. The percentage cover of vascular plants was recorded in 4 permanent plots per field on 7 restored fields between 2006 and 2009. Ten aboveground biomass samples per field were also collected in June in each year. We addressed two questions: (i) How do seed sowing and annual mowing affect the species richness, biomass and cover of weeds? (ii) How fast does the cover of sown grasses develop after seed sowing? Weedy species were characteristic in the first year after sowing. In the second and third year their cover and species richness decreased. From the second year onwards the cover of perennial grasses increased. Spontaneously immigrating species characteristic to the reference grasslands were also detected with low cover scores. Short-lived weeds were suppressed as their cover and biomass significantly decreased during the study. The amount of litter and sown grass biomass increased progressively. However, perennial weed cover, especially the cover of Cirsium arvense increased substantially. Our results suggest that grassland vegetation can be recovered by sowing low diversity mixtures followed up by yearly mowing. Suppression of perennial weed cover needs more frequent mowing (multiple times a year) or grazing.

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Authors: I. Tamáska, Z. Vértesy, A. Deák, P. Petrik, K. Kertész and László Biró

Bioinspired 1+2D nanoarchitectures inspired by the quasi-ordered structures occurring in photonic nano-architectures of biological origin, like for example butterfly scales, were produced by depositing a layer of SiO2 nanospheres (156 nm and 292 nm in diameter) on Si wafers, over which a regular multilayer composed from three alternating layers of SiO2 and TiO2 was deposited by physical vapor deposition. Flat multilayers were deposited in the same run on oxidized Si (324 nm SiO2 thickness) for comparison. Different types of disorder (in plane and out of plane) were purposefully allowed in the 1+2D nanoarchitectures. The positions of the specular reflection maxima for the flat multilayer and for the two different bioinspired nanoarchitectures were found to be similar. Additionally to this, the bioinspired nanoarchitectures exhibited angle independent diffuse reflection too, which was absent in the flat multilayer. Different model calculations were made to explain the specular and diffuse optical properties of the samples. Satisfactory agreement was obtained between experimental data and model calculations.

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Authors: A. Doros, B. Nemes, Z. Máthé, A. Németh, E. Hartmann, Á. P. Deák, Zs. F. Lénárd, D. Görög, I. Fehérvári, Zs. Gerlei, J. Fazakas, Sz. Tóth and L. Kóbori

Abstract

Introduction

Hepatic artery complication represents recognized sequel of liver transplantation that carries significant morbidity and mortality. Besides retransplantation, hepatic artery recanalization is provided surgically, or by percutaneous angioplasty and stent placement. This study provides an analysis of a single center experience comparing surgical and interventional treatments in cases of early hepatic artery complications.

Methods

In this retrospective single center study, 25 of 365 liver transplant recipients were enrolled who developed early hepatic artery complication after transplantation. Percutaneous intervention was performed in 10 cases, while surgical therapy in 15 cases. Mean follow-up time was not different between the groups (505±377 vs. 706±940 days, respectively).

Results

6 patients in the Intervention Group and 10 patients in the Surgery Group are alive. The retransplantation rate (1 and 3) was lower after interventional procedures, while the development of biliary complications was higher. The mortality rate was higher after operative treatment (2 and 5).

Conclusion

Interventional therapy is a feasible and safe technique for treatment of early hepatic artery complication after transplantation. Being less invasive it is an invaluable alternative treatment having results comparable to surgical methods.

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Authors: P. Török, T. Miglécz, O. Valkó, K. Tóth, A. Kelemen, Á.-J. Albert, G. Matus, A. Molnár V, E. Ruprecht, L. Papp, B. Deák, O. Horváth, A. Takács, B. Hüse and B. Tóthmérész

In the present paper we report original thousand-seed weight data for the flora of the Pannonian Basin. Our goal was to demonstrate the usefulness of seed weight databases by analysing seed weight data in relation to social behaviour types and life forms. We specifically asked the following questions: (i) how the seed weights are related to social behaviour type categories; (ii) how the life form of the species influences seed weight differences between respective social behaviour types? Own weight measurements are provided for 1,405 taxa; and for 187 taxa we published seed weight data for the first time: these were mostly endemics, orchids and/or species with Pontic, Caspian or continental distribution. Several taxonomic or functional groups are underrepresented in our database, like aquatic plants, rare arable weeds and sub-Mediterranean species. Problematic taxa, some difficult-to-harvest species or species with low seed production and cultivated adventives are also underrepresented. We found that the plant strategies expressed by social behaviour types were significantly different in terms of seed weights. The lowest seed weight scores were found for natural pioneers, whereas the highest ones were found for adventives and introduced cultivated plants. Short-lived herbaceous species had significantly higher seed weight scores than herbaceous perennials. No significant differences were found between specialists and generalists within the stress tolerant group. We found that short-lived graminoids possess heavier seeds than perennial graminoids, perennial and annual forbs. Naturalness scores were negatively correlated with seed weights. Our findings showed that seed collections and databases are not only for storing plant material and seed weight data, but can be effectively used for understanding ecological trends and testing plant trait-based hypotheses. Even the identified gaps underline the necessity of further seed collection and measurements.

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Authors: E. Hartmann, A. Németh, Gy. Juharosi, Zs. Lénárd, P. Á. Deák, V. Kozma, P. Nagy, Zs. Gerlei, I. Fehérvári, B. Nemes, D. Görög, J. Fazakas, L. Kóbori and A. Doros

Abstract

Hepatocellular carcinoma, which has developed in liver cirrhosis is a disease where liver transplantation can provide a cure both for the tumour and the underlying liver damage. However, patients can only be transplanted when the tumour number and size do not exceed the Milan criteria. Tumour ablation methods — such as radiofrequency ablation — can provide a chance to make the patient eligible for transplantation. Among the 416 Hungarian liver transplanted patients there are 6 who had received different types of ablative therapy as bridging therapy in different institutions. On the basis of analysis of the patients' data we created a guideline for the treatment of cirrhotic patients with hepatocellular carcinoma with the aim of developing a uniform Hungarian approach.

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