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The two naphthol isomers were investigated in different organic solvents by taking cyclic voltammograms, and fouling took place on a platinum electrode surface, except for dimethyl sulfoxide and dimethyl formamide. Studies in allyl alcohol rarely used in electrochemical investigations pointed to the importance of the carbon–carbon double bond as electrode deactivation was remarkably faster compared with its saturated analog solvent. Similarly, the use of the other unsaturated solvent mesityl oxide in the electropolymerization of naphthols resulted in different findings compared with methyl isobutyl ketone. As dimethyl formamide was the best choice concerning the solubility of products, it was successfully tested in electrode renewal after deactivation in an aqueous solution. The increase in dimethyl formamide content led to more and more improved reproducibility of the currents of the outlined aromatic compounds. Naphthol isomers were assessed in the suppression of layer growth originating from the electrooxidation of another monomer phloroglucinol. Its simultaneous electrooxidation with naphthol monomers had a dramatic effect on layer morphology and it was found that instead of a coherent organic layer originating from the homopolymerization of phloroglucinol, the copolymerization with naphthols led to the development of more porous and rougher deposits. The suppressed electropolymerization thus increased sensitivity towards a chosen redox active compound, 4-methoxyphenol.

In the first part of this study, the electrochemical polymerization of two compounds, 3,5-dihydroxybenzoic acid and 2′,6′-dihydroxyacetophenone, was compared in dimethyl sulfoxide solvent on platinum and glassy carbon electrodes. The voltammograms obtained showed remarkable differences between the two monomers and between the two electrode materials. The acetophenone derivative formed electropolymer remnants at the electrodes, while in the case of the benzoic acid derivative, practically no passivation occurred, and the scanning electron microscopic results reinforced this. A few stackings adsorbed only after electropolymerization from a highly concentrated solution of dihydroxybenzoic acid. As a modifying layer on the platinum and glassy carbon electrodes, the prepared films from 2′,6′-dihydroxyacetophenone were tested for tributylamine in acetonitrile and in an aqueous solution of a redox-active compound, hydroquinone, during the stirring of the solution. More stable amperometric current signals could be reached with modified platinum than with glassy carbon, and the significant influence of the organic washing liquid after deposition was established via the study of noise level. In this respect, acetone was the best choice. The amperometric signals with the modified platinum obtained upon the addition of aliquots of the stock solution resulted in a 3.29 μM detection limit.

It is our main objective to find the critical load for three beams with cross sectional heterogeneity. Each beam has three supports, of which the intermediate one is a spring support. Determination of the critical load for these beams leads to three point boundary value problems (BVPs) associated with homogeneous boundary conditions—the mentioned BVPs constitute three eigenvalue problems. They are solved by using a novel solution strategy based on the Green functions that belong to these BVPs: the eigenvalue problems established for the critical load are transformed into eigenvalue problems governed by homogeneous Fredholm integral equations with kernels that can be given in closed forms provided that the Green function of each BVP is known. Then the eigenvalue problems governed by the Fredholm integral equations can be manipulated into algebraic eigenvalue problems solved numerically by using effective algorithms. It is an advantage of the way we attack these problems that the formalism established and the results obtained remain valid for homogeneous beams as well. The numerical results for the critical forces can be applied to solve some stability problems in the engineering practice.

In numerous scientific and engineering applications, it is imperative to study the reactivity of material surfaces at a microscopic level. Scanning electrochemical microscopy (SECM) is a prevalent technique utilized to investigate and probe the electrochemical properties of surfaces. However, due to the inherent dependence of SECM on the distance between the sample and tip, uneven samples can pose a challenge, resulting in inaccurate measurements and incomplete understanding of material behavior. In this paper, we propose a novel approach for resolving this issue using contact-mode carbon fiber electrodes in potentiometric mode. The methodology introduced in this study presents a progressive development over the conventional feedback mode in certain circumstances, as it is capable of monitoring sample conductivity independent of its topography. This paper exemplifies two specific cases involving a tilted and a rough surface. A comparative analysis of the results obtained using the conventional feedback mode and the proposed method was conducted to further validate its efficacy. The findings demonstrate that the proposed method is highly effective in studying tilted and rugged substrates.

Due to the medical importance of dibenzoylmethane, one of the aims of the study was to find an appropriate packing material and a biologically friendly co-solvent to help its introduction into living systems. Accordingly, redox properties of dibenzoylmethane were investigated on glassy carbon electrodes in acetonitrile and in 1-propanol with cyclic voltammetry, and showed a diffusion-controlled process. In the anodic window, an oxidation peak appeared at around 1.9 V in both solvents. Cycling repeatedly between 0 and 2 V, the reproducibility of this peak was acceptable, but when extending the window to higher potentials, the electrode deactivated, obviously due to electrode material. The addition of the investigated tetrakis(3,5-dicarboxyphenoxy) cavitand did not significantly change the voltammograms. Further electrochemical experiments showed that the coexistence of water in acetonitrile and 1-propanol drastically reduces the solubility of dibenzoylmethane. Moreover, very rapid electrode deactivation occurred and this fact made the use of electrochemical methods complicated. Considering that both the cavitand and dibenzoylmethane are soluble in dimethyl sulfoxide, the interaction of these species was investigated and formation of stable complexes was detected. This observation was verified with fluorescence quenching studies. The mixture of water and dimethyl sulphoxide also dramatically improved the solubility of the cavitand–dibenzoylmethane complex at high excess of water. The addition of cavitand improved the solubility of dibenzoylmethane, a property which supports the application of dibenzoylmethane in therapy.

The electropolymerization of three phenylphenol isomers was studied in methyl isobutyl ketone and mesityl oxide, and the remarkable differences highlighted the importance of the carbon–carbon double bond in mesityl oxide. In the case of each substrate, a brownish deposit formed during the electrooxidation. The obvious difference between the polymers formed from the two solvents was recognized via voltammetric signal enhancement of 4-methoxyphenol and 4-chlorophenol, and it was only observed in the case of mesityl oxide. The experiments highlighted that incorporation of a cavitand with biphenyl groups on the upper rim of the polymers of phenylphenols improved the results to a small extent. The cavitand was, itself, electroactive without any fouling effect. As 2-phenylphenol is by far the cheapest of the three isomers, a cavitand was incorporated into its polymer, which was exploited to solve analytical problems while mesityl oxide was used as solvent. Useful quantifications were achieved in organic solvents; however, it failed under aqueous conditions due to the high hydrophobicity of the deposit. Application of differential pulse voltammetry for 4-methoxyphenol and 4-chlorophenol gave detection limits of 9.28 and 50.8 μM in acetonitrile, respectively. This procedure resulted in the immobilization of cavitand derivatives onto the electrode’s surface, and the layer formed offered selective sensing of phenols by electrochemical methods.

Tanulmányunkban a magyarországi kollektivizálás második hullámát egy, a társadalomtudományban használatos módszer adaptálásának segítségével vizsgáljuk, rámutatva, hogy a nagy adatbázisok elemzése milyen nagyobb, általánosabb történettudományi összefüggések levonására kínál lehetőségeket. Majd ugyanezt a kutatási kérdéskört egy szövegbányászati módszer, az úgynevezett topikmodellezés alkalmazásával elemezzük. Írásunk célja annak illusztrálása, hogy az egyre nagyobb számban elérhető digitális gyűjteményeknek a hazai történettudomány számára még részben újfajta módszerekkel történő elemzése milyen lehetőségeket és korlátokat rejt magában. Elemzésünk a korai Kádár-korszak agrárpolitikai jogszabályalkotásának vizsgálatát végzi el, arra a fő kutatási kérdésre keresve a választ, hogy milyen módon tükröződik vissza a jogszabályalkotásban a korszak gazdaságpolitikája, milyen módon reagált a jogszabályalkotás a korszak gazdaság- és társadalompolitikai változásaival kapcsolatban felmerülő szabályozási igényekre. A témaalapú osztályozás mellett szövegeinket szövegbányászati módszerekkel is vizsgálat alá vesszük, elemzésünk harmadik részében pedig kísérletet teszünk a két módszer kombinálására – azzal a céllal, hogy összefüggést találjunk a CAP-kódkönyvben meghatározott közpolitikai topikok, konkrétabban az agrárpolitikai altopikok, valamint a topikmodellezés során kapott témák között.

2019. június 25-én Kiss László felkérésére három közgazdász, Bod Péter Ákos (egyetemi tanár, Budapesti Corvinus Egyetem), Farkas Péter (nyugdíjas főmunkatárs, KRTK Világgazdasági Intézet) és Trautmann László (egyetemi docens, Budapesti Corvinus Egyetem) ült le beszélgetni a globalizáció és a közgazdaság-tudomány kérdéseiről. A beszélgetést jelentős szerkesztési munka követte, amely során minden szerző kiegészíthette saját hozzászólását. Kiss Endre filozófus pedig, aki sajnos nem tudott részt venni a beszélgetésen, írásban fogalmazta meg véleményét. A kéziratot 2019. október 29-én zártuk le.

Efficient nitrogen (N) nutrition has been reported to have the potential to alleviate the drought stress damages by maintaining metabolic activities even at low tissue water potential. The goal of our research was to find a correlation on the genotype level between the effect of different amounts of nitrogen nutrition and water supply at different growth stages. A small-plot experiment was established with three maize hybrids and three levels of nitrogen, and two different amounts of water supply were applied during the vegetation period of 2018 and 2019. Chlorophyll fluorescence parameters were detected, as well as potential and actual photochemical efficiency of PSII, at three growth stages: eight-leaf stage, tasseling, silking. At physiological maturity, the yield of hybrids was also measured. While only genotype differences were described among the investigated parameters in the V8 stage, treatment effects were also realized based on the measured chlorophyll fluorescence parameters during the tasseling and silking stages. Beyond the significant effect of irrigation, a similar impact was declared in the case of 80 kg ha−1 N treatment at the later growth stages. Pronounced correlation was described between chlorophyll fluorescence parameters and yield mainly under irrigated conditions. Our result suggested that lower N nutrition may be sufficient mainly under irrigated conditions, and in vivo chlorophyll fluorescence parameters are appropriate for detecting the effect of environmental factors in different growth stages.

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Copyright of Magyar Állatorvosok Lapja is the property of Herman Otto Intezet Nonprofit Kft. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Magyar Nőorvosok Lapja is the property of Hungarian Society of Obsterics & Gynaecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Gerundium is the property of University of Debrecen and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)