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Osama I. El-Sabbagh, Yamany B. Yamany and Hany A. Eldeab

Abstract

Novel complexes of Ru (III), Cu (II) and Au (III) (2–4) were prepared using 6-phenyl-2-thioxo-4-(trifluoromethyl)-1,2- dihydropyridine-3-carbonitrile (HL, 1) adopting either electrochemical or traditional chemical methods. The electrochemical method is preferred in the synthesis of the complexes than the chemical one because it affords pure products with higher yields in shorter reaction time. The novel thiopyridine complexes were characterized by elemental analyses, IR, 1H, 19F-NMR, TGA and DTA measurements. The antimicrobial activity evaluation revealed that the complex bearing copper metal 3 has nearly the same activity as the reference drug ciprofloxacin. Anti-inflammatory activity evaluation showed that complex 4 containing gold displayed anti-inflammatory activity higher than the reference drug celecoxib upon using carrageenan rat hind paw edema method.

Open access

Olusola Samuel Jolayemi

Abstract

This research demonstrated the significance of variety and thermal holding time (THT) at constant temperature (95 °C) on quality characteristics of mango juice. Eighteen samples from Mado, Julie and Kent mango varieties were produced using full factorial design. Quality parameters, sensory and microbial properties were determined. Variety and THT were significant for most notable variables considered except for some sensory properties. Juice of Julie had the highest vitamin C at 60s, while Mado were superior in virtually all other chemical parameters; having 31.93 – 49.97 µg/100g pro-vitamin A, 51.10 – 113 mg/100g total phenol, 25.60 – 81.40 mg/100g total flavonoid, 1.26 – 1.48 mg/L tannin and 12.60 – 13.60% °Brix. Microbial qualities were influenced by THT; with 60s long enough to achieve stable products. PCA cluster analysis further emphasized variety as the most quality-determining factor in mango juice.

Open access

Csaba Lentner, László Nagy, László Vasa and Szilárd Hegedűs

Abstract

The aim of this paper is to analyse legal and financial dynamics of the self-governance in three countries of the Visegrad Group: the Czech Republic, Hungary and Slovakia. The paper explores compliance with the European Charter of Local Self-Government, financial independence and operational features of self-governance. The paper provides an overview of the regulatory environment that was set up for the local government in the Visegrad countries, examines the powers by local government, and the degree of its financial independence. The financial aspects of self-government are compared, and compliance with major fiscal rules is examined.

Open access

Krzysztof Kowalczyk, Justyna Gołąbek, Katarzyna Przywecka and Barbara Grzmil

Abstract

Anticorrosive epoxy and polyurethane coatings were compounded using zinc-free nanosized phosphates of strontium (SP) or strontium and aluminum (SAP). For comparison, a nanosized calcium aluminum ammonium phosphate (CAP) and a microsized zinc phosphate (ZP) were tested. Results of salts spray and cyclic corrosion tests revealed better anticorrosive properties of the SAP-based coatings in relation to the samples with the other Zn-free fillers or ZP. Electrochemical noise tests of uncoated steel in aqueous suspensions of the phosphates exhibited similar corrosion inhibition efficiency of the Sr-based phosphates and ZP, and worse anticorrosive features of CAP. Electrochemical impedance spectroscopy did not show better protective properties of ZP-based coatings than the samples with the Zn-free fillers.

Open access

K. Szmuc, M. Kus-Liskiewicz, Ł. Szyller, D. Szmuc, M. Stompor, I. Zawlik, T. Ruman, S. Wołowiec and J. Cebulski

Abstract

The composite containing nanosilver uniformly deposited on matrix composed of CaHPO4 x 2H2O (brushite, ca 89 mass %), CaHPO4 (monteonite, ca 9.5 mass%), and Ag3PO4 (0.5 mas%) was obtained by addition of calcium nitrate and silver nitrate aqueous solution at 30:1 Ca:Ag molar ratio into excess of (NH4)2PO4 solution at pH 5.0 – 5.5. The isolated solid was characterized by STEM, XRD, and LDI mass spectrometry. It has been found that nanosilver was uniformly distributed within composite as <10 nm diameter sized nanoparticles. Determination of silver by AAS showed that 60% of silver is present as Ag(0) nanoparticles, the present as matrix Ag3PO4 as identified by XRD method. The composite showed strong growth inhibition in E. coli and P. aeruginosa strains, and moderate towards S. aureus. The C. albicans cells were the most resistant to the tested material, although still composite was moderately cytostatic for the yeast.

Open access

Yunfeng Hu, Liping Zhang, Jinjin Wei and Zengyu Wei

Abstract

In order to study the quality changes and shelf life of chitosan coated eggs during storage, the quality, gas chamber diameter, yolk coefficient and the quality change of Hough unit during storage were measured at temperature of 5, 20 and 35 ℃. The Pearson correlation between the quality indexes and the egg Hough’s unit value was analyzed, and the yolk coefficient was analyzed dynamically and the shelf life prediction model was based on the basis of the Arrhenius equation. The results showed that the quality of eggs, egg yolk coefficient, and Huff units all decreased with the extension of storage time, and the diameter of the air chambers of eggs showed an increasing trend with the extension of storage time. Moreover, the storage environment at high temperature (20 and 35 ℃) had a significant effect on the quality deterioration than the low temperature (5℃) storage environment; The correlation coefficient between egg yolk coefficient and Hough unit is the highest at all temperatures, which can be used as an important indicator for shelf life prediction; According to the changing rule of egg quality, the yolk coefficient can establish a first order kinetic model. According to the model established by the egg yolk coefficient, the coefficient R2 of the fitting curve of the predicted value and the measured value is 0.9825, and the average relative error P is 9.32% and less than 10%. The kinetic relationship between yolk coefficient and temperature is well described. At the same time, based on the dynamic model, the shelf life prediction model of chitosan-coated eggs based on yolk coefficient was determined by the dynamic model. The average relative error was 7.6%, less than 10%, which indicated that the egg shelf life prediction model based on the change of egg yolk coefficient was feasible.

Open access

M. Danková, A. Kalendová and J. Machotová

Abstract

The requirements put on coating materials are more and more stringent mainly in the environmental domain, especially as regards VOC emissions. This is why water-based binders as alternatives to solvent-based binders, to provide paints possessing equally good use properties, are intensively sought. The objective of this work was to assess the anticorrosion and chemical properties of paint films based on new self-cross-linking acrylic latexes. The latexes were synthesized via two--step emulsion polymerisation to obtain a core-shell system. Nanostructural ZnO in an amount of 1.5 wt. % was added to the system during the latex binder synthesis. Paints with an enhanced corrosion resistance and chemical resistance of the films were prepared. The binders prepared were pigmented with anticorrosion pigments and their properties were compared to those of commercial water-based dispersions with either identical or different paint film formation mechanisms. The results gave evidence that if a well-selected pigment is used, the binders can be used to obtain anticorrosion coating materials for metallic substrates.

Open access

Mohammed A. Abdulaziz, Abdulrahman A. Bakri, Saleh A. Al-Zahrani, Majed S. Al-Zahrani, Abdulrahman N. Al-Lehebi, Fadil M. Banjar and Mohand I. Nabag

Abstract

This study aims at investigating the potential of Acacia gerrardii pod for the removal of Cr(VI) in batch system. Effect of solution pH, biosorbent dosage, initial concentration of Cr(VI), contact time on the removal process was examined. Complete removal of hexavalent chromium was achieved at pH values 1.0 and 2.0 whereas maximum removal of total chromium was obtained at pH of 3.0. The study showed that the biosorption and bioreduction mechanisms were involved in the removal process. The time required for complete removal of Cr(VI) using the pod of Acacia gerrardii was shortened with an increase in biomaterial dosage and decrease in Cr(VI) concentration. Kinetic data was well described using Park kinetic model. Freundlich isotherm model adequately fitted the equilibrium data indication multilayer adsorption of total chromium on the surface of biomaterial. The pod of Acacia gerrardii could be used efficiently for the removal of hexavalent chromium from aqueous solutions.

Open access

Imola Szabó, József Lehota and Róbert Magda

Abstract

This study examines opportunities and hindering factors of box schemes as they have been operating for many years in Hungary, but there are several facts which make it hard for box schemes to become parts of the daily routine in the lives of Hungarian consumers. The first fact is price sensitiveness and willingness to pay price premium for environmentally friendly products, including fresh fruits and vegetables. The second fact is the lack of many products in supplies of box schemes, because fruits and vegetables are seasonal products, but this reason is not always acceptable for customers. The third fact is time wasting, which is a really hindering factor. Finally, interpretation of sustainability is the most important in the eyes of consumers. Our goal is to show how the relation between factors leads to opportunity of growth.

Open access

A. Guzanová, J. Brezinová, D. Draganovská and P.O. Maruschak

Abstract

The paper focuses on assessment the resistance of hot-sprayed coatings applied by HVOF technology (WC–Co–Cr created using powder of two different grain sizes) against erosive wear by dry-pot wear test in a pin mill at two sample angles. As these coatings are designated for the environment with varying elevated temperatures and often are in contact with the abrasive, the coatings have been subjected to thermal cyclic loading and their erosive resistance has been determined in as-sprayed condition and after the 5th and 10th thermal cycles. The corrosion resistance of coatings was evaluated by linear polarization (Tafel analysis).