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Furko M.,Bay Zoltan Nonprofit Ltd. for Applied Research | Jiang Y.,University of Leeds | Wilkins T.,University of Leeds | Balazsi C.,Bay Zoltan Nonprofit Ltd. for Applied Research
Ceramics International | Year: 2016

A successful electrodeposition method for preparing silver and zinc modified bioactive calcium phosphate layers onto surgical grade titanium alloy material (Ti6Al4V) was developed. The coatings were deposited on the Ti6Al4V surface by pulse current at 70 °C from an electrolyte containing adequate amounts of calcium nitrate, ammonium dihydrogen phosphate, zinc nitrate and silver nitrate. The corrosion resistivity of the bioceramic coatings was assessed in conventional Ringer's solution in a three electrode open cell by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results revealed the pure bioactive calcium phosphate (CaP) coated implant materials to possess the highest resistivity to corrosion, while the silver and zinc doped CaP layer showed at least one order of magnitude lower corrosion resistance. These modified CaP coatings can be further considered as antimicrobial coatings with enhanced biocompatibility. The morphology and structure of the coatings were characterized by Scanning electron microscopy (SEM), Energy-dispersive X-ray Spectroscopy (EDX) and X-ray diffraction (XRD) that confirmed the pulse current deposited CaP layer to consist of a mixture of different calcium phosphate phases such as hydroxyapatite (HAp), monetite (dicalcium phosphate, CaHPO4) as well as other Ca-containing components, portlandite (Ca(OH)2) and parascholzite (CaZn2(PO4)2(H2O)2). © 2015 Elsevier Ltd and Techna Group S.r.l.


In-situ synthesized Nb(C,N) reinforced metal-ceramic composite layers were fabricated on nitridable (16MnCr5) and non-nitridable (S235J) steel surface by combined laser melt injection technology and ferritic nitrocarburizing treatment. The feasibility of processing composites layer by an in situ reaction using laser beam were carried out. Beside that the hardness of the treated layers increases up to 1000-1170 HV0.5 in the diffusion zone and after it the hardness of the samples reach 300-450 HV0.5, which is related the Nb alloying depth (1200-1400 μm). The results of the composite layer are presented in this paper. © (2015) Trans Tech Publications, Switzerland.


Sandor R.B.,Bay Zoltan Nonprofit Ltd. for Applied Research | Istvan Z.,Bay Zoltan Nonprofit Ltd. for Applied Research
Re-Engineering Manufacturing for Sustainability - Proceedings of the 20th CIRP International Conference on Life Cycle Engineering | Year: 2013

Increasing demands are shown regarding the reuse of the products - regardless of the countries - by means of differences of living and this is preferred also after the waste prevention based on the waste hierarchy in the Framework Directive of the European Union. These reasons can generate the increasing of the special kind of used item handling/trading work. The whole life-cycle assessment analyses a dynamically developing area (used item collection and trade) from environmental and sociological aspect. The aim of the research was the examination of the illegal activity for many years compared with alternative formalized ideas.


Buday B.,Drug Research Center | Pach F.P.,Bay Zoltan Nonprofit Ltd. for Applied Research | Literati-Nagy B.,Drug Research Center | Vitai M.,Drug Research Center | And 2 more authors.
Bone | Year: 2013

Objective: The osteoblast-derived protein osteocalcin (OCN) is known to be involved in glucose metabolism by increasing adiponectin secretion from adipocytes. Recently, OCN was also found to enhance testosterone production in mouse testes, suggesting that OCN effects on energy metabolism may be mediated through testosterone. Our aim was to assess a possible gender difference in the metabolic effect of OCN in humans. Methods: We included 135 women and 155 men exhibiting changes in glucose tolerance in our study. Oral and intravenous glucose tolerance tests (OGTT and IVGTT, respectively) and a hyperinsulinemic normoglycemic clamp were performed. For clamp indices, whole body (M1) and muscle (M2) glucose uptake values were used. Leptin, adiponectin serum lipid, lipoprotein, total serum OCN and testosterone levels, and body composition were determined. Results: Higher OCN values were associated with improving metabolic state in both genders. Adiponectin and OCN correlated significantly only in females (r. = +. 0.254, p. = 0.0029), while in men, testosterone and OCN values showed a significant positive correlation (r. = +. 0.243, p. = 0.0023), independent of age, BMI, HbA1c and body composition. In women, adiponectin was confirmed by feature selection analysis as being an independent determinant of OCN, in addition to age and three of the IVGTT glucose values. In men, besides M1, BMI, M2, leptin, body fat percent, and the 90-minute OGTT glucose reading testosterone, but not adiponectin were identified as independent contributors for OCN. Conclusion: We confirmed the 'classic' adiponectin-mediated insulin-sensitising effect of OCN only in females. In men, a testosterone-mediated OCN metabolic effect is more likely. © 2013 Elsevier Inc.


Istvan Z.,Bay Zoltan Nonprofit Ltd. for Applied Research | Chrabak P.,Bay Zoltan Nonprofit Ltd. for Applied Research
Osterreichische Wasser- und Abfallwirtschaft | Year: 2013

The environmental issues in Hungary have high priority nowadays especially on the field of waste management. The major driven force behind it is the intention to meet the related EU engagements, besides the predecessor Act was fairly outdated. The draft of the new "Act on Waste" triggered special focus even from the international press and the interested waste management companies due to its reforming plans. According to the interest of different stakeholders, lobbying and discussions took place with the Government. So, the article aims to give a short introduction on the most important changes, especially from the aspect of municipal waste management companies. © 2012 Springer-Verlag Wien.


Danku Z.,Debrecen University | Lenkey G.B.,Bay Zoltan Nonprofit Ltd. for Applied Research | Kun F.,Debrecen University
Applied Physics Letters | Year: 2015

We study the statistical features of magnetic noise accompanying the dynamic fracture of steel samples during mixed type fracture, where the overall ductile character of crack propagation is interrupted by a sudden brittle jump. The structure of the voltage time series is investigated by identifying discrete peaks which correspond to elementary steps of the jerky cracking process. We show that the height, duration, area, and energy of peaks have power law distributions with exponents falling close to the corresponding values of pure ductile fracture. For single peaks, a power law correlation of the height and area with the width is evidenced; however, the mixed nature of fracture gives rise to a crossover between two regimes of different exponents. The average pulse shape of micro-cracking events has a parabolic form with a right handed asymmetry similarly to quasi-static fracture propagation. The asymmetry emerges due to stress localization at the advancing crack front. © 2015 AIP Publishing LLC.


Torok A.,Bay Zoltan Nonprofit Ltd. for Applied Research | Nagy A.,University of Pannonia | Kalomista I.,Bay Zoltan Nonprofit Ltd. for Applied Research
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

The recent indoor localization techniques use inertial sensors for position estimations in order to obtain a certain degree of freedom from infrastructure based solutions. Unfortunately, this dependency cannot be completely eliminated due to the cumulative errors induced in the localization process. While many methods are designed to reduce the required number of reference points, completely infrastructure independent solutions are still missing. In this paper we extend the approach of DREAR, a mobile-based context-aware indoor localization framework. DREAR exploits the ability to recognize certain human motion patterns with a smartphone, representing activities related to walking, climbing stairs, taking escalators, etc. This allows the detection of corridors, staircases and escalators, knowledge which can be used to create building interior related reference points. Based on these a scenario specific context interpreter controls the localization process and provides position refinement for the elimination of the cumulated errors. However, due to the cumulated errors in the trajectory, in case of neighbouring reference points with similar characteristics an adequate distinction cannot made, based solely on the detected activities, which leads to wrong reference point associations and erroneous location refinements. Thus, we extended DREAR with a trajectory reconstruction algorithm, to cope with these errors and their effect on the outcome of reference point selection. The proposed solution is evaluated in a complex subway scenario, its performance is analysed focusing on path reconstructions and the benefits of using specific context-related information. The results are promising, the proposed algorithm presents further improvements relative to the performance of DREAR, providing an excellent localization and path reconstruction solution. © Springer International Publishing Switzerland 2015.


Furko M.,Bay Zoltan Nonprofit Ltd. for Applied Research | Jiang Y.,University of Leeds | Wilkins T.A.,University of Leeds | Balazsi C.,Bay Zoltan Nonprofit Ltd. for Applied Research
Materials Science and Engineering C | Year: 2016

In our research nanostructured silver and zinc doped calcium-phosphate (CaP) bioceramic coatings were prepared on commonly used orthopaedic implant materials (Ti6Al4V). The deposition process was carried out by the pulse current technique at 70°C from electrolyte containing the appropriate amount of Ca(NO3)2 and NH4H2PO4 components. During the electrochemical deposition Ag+ and Zn2 + ions were introduced into the solution. The electrochemical behaviour and corrosion rate of the bioceramic coatings were investigated by potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS) measurements in conventional Ringer's solution in a three electrode open cell. The coating came into contact with the electrolyte and corrosion occurred during immersion. In order to achieve antimicrobial properties, it is important to maintain a continuous release of silver ions into physiological media, while the bioactive CaP layer enhances the biocompatibility properties of the layer by fostering the bone cell growth. The role of Zn2 + is to shorten wound healing time. Morphology and composition of coatings were studied by Scanning Electron Microscopy, Transmission Electron Microscopy and Energy-dispersive X-ray spectroscopy. Differential thermal analyses (DTA) were performed to determine the thermal stability of the pure and modified CaP bioceramic coatings while the structure and phases of the layers were characterized by X-ray diffraction (XRD) measurements. © 2016 Elsevier B.V. All rights reserved.


PubMed | University of Leeds and Bay Zoltan Nonprofit Ltd. for Applied Research
Type: | Journal: Materials science & engineering. C, Materials for biological applications | Year: 2016

In our research nanostructured silver and zinc doped calcium-phosphate (CaP) bioceramic coatings were prepared on commonly used orthopaedic implant materials (Ti6Al4V). The deposition process was carried out by the pulse current technique at 70 C from electrolyte containing the appropriate amount of Ca(NO3)2 and NH4H2PO4 components. During the electrochemical deposition Ag(+) and Zn(2+) ions were introduced into the solution. The electrochemical behaviour and corrosion rate of the bioceramic coatings were investigated by potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS) measurements in conventional Ringers solution in a three electrode open cell. The coating came into contact with the electrolyte and corrosion occurred during immersion. In order to achieve antimicrobial properties, it is important to maintain a continuous release of silver ions into physiological media, while the bioactive CaP layer enhances the biocompatibility properties of the layer by fostering the bone cell growth. The role of Zn(2+) is to shorten wound healing time. Morphology and composition of coatings were studied by Scanning Electron Microscopy, Transmission Electron Microscopy and Energy-dispersive X-ray spectroscopy. Differential thermal analyses (DTA) were performed to determine the thermal stability of the pure and modified CaP bioceramic coatings while the structure and phases of the layers were characterized by X-ray diffraction (XRD) measurements.


PubMed | Bay Zoltan Nonprofit Ltd. for Applied Research, University of Szeged and Synthetic and System Biology Unit
Type: | Journal: Water research | Year: 2016

Nanoscale zero-valent iron (NZVI) is increasingly used for reducing chlorinated organic contaminants in soil or groundwater. However, little is known about what impact the particles will have on the biochemical processes and the indigenous microbial communities. Nanoiron reactivity is affected by the structure and morphology of nanoparticles that complicates the applicability in bioremediation. In this study, the effect of precursors (ferrous sulfate and ferric chloride) and reducing agents (sodium dithionite and sodium borohydride) on the morphology and the reactivity of NZVIs was investigated. We also studied the impact of differently synthesized NZVIs on microbial community, which take part in reductive dechlorination. We demonstrated that both the applied iron precursor and the reducing agent had influence on the structure of the nanoparticles. Spherical nanoparticles with higher Fe(0) content (>90%) was observed by using sodium borohydride as reducing agent, while application of sodium dithionite as reducing agent resulted nanostructures with lower Fe(0) content (between 68,7 and 85,5%). To determine the influence of differently synthesized NZVIs on cell viability anaerobic enriched microcosm were used. NVZI was used in 0.1g/L concentration in all batch experiments. Relative amount of Dehalococcoides, sulfate reducers (SRBs) and methanogens were measured by quantitative PCR. We found that the relative amount of Dehalococcoides slowly decreased in all experiments independently from the precursor and reducing agent, whereas the total amount of microbes increased. The only clear distinction was in relative amount of sulfate reducers which were higher in the presence of NZVIs synthesized from sodium dithionite.

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