Synthesis of crown ether compounds as potential inhibitors of enzymatic discolouration of foods

The synthesis of the following crown ether containing compounds as potential polyphenol oxidase inhibitors is described: 4'-N(benzo-crown-5)succinamic acid (I), 4'-N(benzo-15-crown-5)malemic acid (II), ester of 4'-N(benzo-15-crown-5)bis[4'-N(benzo-15-crown-5)]phthalamic acid (III) and complex of benzo-18-crown-6 with 2-propenyl-acrylamide (IV). The complexes of I, II and IV with potassium 2-propenyl-acrylamide are also described

Effectiveness of some crown compounds on inhibition of polyphenoloxidase in model systems and in apple

Enzymatic browning is (in most cases) an undesirable reaction which usually impairs the sensory properties and chemical changes in raw fruits and vegetables after mechanical operations (such as peeling, coring or slicing). A great emphasis is put on research to develop new methods to prevent enzymatic browning especially in fresh-cut (minimally processed) fruits and vegetables. The inhibition effect of crown compounds, macrocyclic ethers, benzo-18-crown-6 with sorbic acid and benzo-18-crown-6 with potassium sorbate, on polyphenoloxidase (PPO) activity was studied. The effectiveness of these compounds was evaluated by using 3,4-dihydroxy phenylalanine (L-DOPA), and chlorogenic acid (3-o-caffeoyl-D-quinic acid), the most widespread natural PPO substrates in fruits and vegetables, as well as browning inhibition substances on the cut surface of apples. Results showed that crown compounds used in this study were effective, both as inhibitors of the oxidation of phenolic compounds (PPO substrates) in model solutions and as inhibitors of enzyme discolorations of real systems (fresh-cut apples). In the earlier published papers (V UKOVI C 'et al., 1999) the synthesis of crown compound used in this study was presented

Polymerization, Thermal Stability and Degradation Mechanism of (Meth)acryl-Dicyclohexylurea and (Meth)acryl-Diisopropylurea Copolymers with Styrene and α-Methylstyrene

U radu je opisan utjecaj dicikloheksiluree (DCU) i diizopropiluree (DiPrU), u bočnom lancu monomera na osnovi (met)akrilata, na kopolimerizaciju sa stirenom (St) i α-metilstirenom (α-MeSt), toplinsku stabilnost i mehanizam razgradnje priređenih kopolimera. Polimerizacija je provedena s dibenzoil-peroksidom (Bz2O2) u butanonu ili dioksanu pri 70 °C, do niske konverzije. Rezultati pokazuju izrazite razlike u početnoj brzini polimerizacije i svojstvima polimera akrilatnih i metakrilatnih monomera u ovisnosti o supstituentu u bočnom lancu. Dok N-akril-N,N--dicikloheksilurea (A-DCU) lako homopolimerizira i kopolimerizira sa St-om i α-MeSt-om, N-metakril-N,N-dicikloheksilurea (MA-DCU) ne homopolimerizira niti kopolimerizira s α-MeSt-om, ali kopolimerizira sa St-om iako sporije nego odgovarajući akrilni monomer. Rezultati istraživanja pokazuju da uvođenje diizopropiluree umjesto dicikloheksiluree u metakrilatnom monomeru također utječe na početnu brzinu polimerizacije. Naime, N-(met)akril-N,N--diizopropilurea (MA-DiPrU) ne homopolimerizira niti kopolimerizira s α-MeSt-om. Polimerizacija sa St-om je sporija u usporedbi s odgovarajućim monomerom koji sadrži DCU. Kopolimerizacija je statistička reakcija u kojoj je, neovisno o sastavu smjese komonomera, uvijek veći udjel St-a u kopolimeru. Toplinsko ponašanje svih polimera u osnovi je slično. Zagrijavanjem pri temperaturama od 100 °C - 450 °C razgrađuju se dvostupnjevitim mehanizmom. U prvom stupnju pri temperaturama od 180 °C - 250 °C dolazi do izdvajanja cikloheksilizocijanata (C6H11NCO), odnosno izopropilizocijanata (C3H7NCO). Čvrsti ostaci identificirani su kao kopolimeri N-(met)akril-cikloheksilamida (A-CHA, MA-CHA), odnosno N-(met)akril-izopropilamida (MA-iPrA) sa St-om ili α-MeSt-om. Stabilni su do 280 °C, a zatim se u jednom stupnju razgrađuju pri temperaturama od 280 °C - 450 °C.This paper describes the polymerization of N-acryl-N,N\u27-dicyclohexylurea (A-DCU), N-methacryl- N,N\u27-dicyclohexylurea (MA-DCU) and N-methacryl-N,N\u27-diisopropylurea (MA-DiPrU) monomers with styrene (St) and α-methylstyrene (α-MeSt), thermal stability and degradation mechanism of prepared copolymers. Free-radical initiated polymerization was performed to low conversion by using dibenzoyl peroxyde (Bz2O2) in butanone at 70 °C under nitrogen stream. It was found that the pendant group in (meth)acrylic monomers have high influence to the polymerization as well as to the copolymer properties. A-DCU readily homopolymerized and copolymerized with St and r1,A-DCU = 0.72 and r2,α-MeSt= 0.07, while MA-DCU does not homopolymerized or copolymerized with α-MeSt under the same conditions, but copolymerized with St to randomly composed copolymers after a long heating of comonomers. Copolymers A-DCU with α-MeSt prepared under different monomer-to monomer-ratios in the feed have random composition with an azeotropic point at ratio of 0.75 (A-DCU) to 0.25 (St). The initial rate of copolymerization indicates that the rate increases almost linearly with the increase of ratio of A-DCU in the comonomer feed. Reactivity ratios determined by the Kelen-Tüdös method are: r1,A-DCU = 0.72 and r2,α-MeSt = 0.07. Molar mass of copolymers increased from 8.5 to 30 (kg mol-1) when mole ratio of A-DCU to α-MeStin the feed increased from 0.1 to 0.9. Poly(A-DCU) and copolymers with α-MeSt decomposed by two-step mechanism. Under TGA (nitrogen,10 °C min-1) conditions in the first step between 180 °C and 250 °C a quantitative yield of cyclohexylisocyanate (C6H11NCO) separated by a decomposition of dicyclohexylurea (DCU). The thermally stable residue represented poly(acryl-cyclohexylamide), poly(A-CHA), and copolymer with α-MeSt, poly(A-CHA-co-α-MeSt). Glass transition temperature (Tg) of poly(A-DCU) was at 184 °C and Tg of residue, poly(A-CHA), was at 161 °C. Tg\u27s of the copolymers are higher for the copolymer with higher A-DCU content. Tg\u27s of residue are increased also when the content of A-CHA in copolymer increased. Copolymers of A-DCU with St have a random composition with an azeotropic point at a ratio of 0.73 (A-DCU) to 0.27 (St). The rate of copolymerization of A-DCU with St increases by the increase of A-DCU in the feed. The reactivity ratio are: r1,A-DCU = 0.80 and r2, St = 0.50. Molar mass of copolymer, prepared at equimolar ratio of monomers in the feed, is Mw = 78.6 kg/mol-1. These copolymers decompose in TGA conditions by two-step mechanism, which correspond to the mechanism explained for the copolymers of A-DCU with α-MeSt. MA-DCU copolymerized with St to randomly composed copolymers. The reactivity ratio determined by the KT method are: r1, MA-DCU= 0.18 and r2, St = 4.84. These values indicate that MA-DCU favors cross-propagation over homopolymerization, while St favors homopolymerization as opposite to cross-propagation. It also shows, that since St is more reactive than MA-DCU, copolymers contain a higher proportion of St units. It was found, that the rate of copolymerization of MA-DCU with St is slower than the rate of copolymerization of A-DCU with St, and that the rate of copolymerization decreases by increasing the amount of MA-DCU in the feed. Molar mass of copolymer prepared at equimolar ratios of comonomers in the feed is Mw=12 kg mol-1. Thermal properties of poly(MA-DCU-co-St) are similar to those previously described in the decomposition of poly[A-DCU-co-St(α-MeSt)]. The results have also shown quite a big influence of DiPrU group in MA-iPrU to the polymerization with St and α -MeSt. Namely, MA-DiPrU does not homopolymerized or copolymerized with α -MeSt, but can polymerize with St only after a long heating of comonomers at 70 °C. The copolymerization of MA-DiPrU with St is a statistical reaction in which regardless of monomer-tomonomer ratios in the feed, an excess of St was in the copolymer. The reactivity ratios (KT method) are: r1, MA-DiPrU = 0.39 and r2, St = 1.03. The obtained data indicate a monomer tendency to alternating structure. The initial rate of copolymerization decreases with increasing the content of MA-DiPrU monomer in the feed. Molar mass of all copolymers are approximately of the same values, Mw = 12 - 8 kg mol-1 and Mn = 8.7 - 6.2 kg mol-1. Thermal behavior of those copolymers correspond to the behavior of acrylic and methacrylic polymers containing DCU as pendant group. Namely, all copolymers decompose under TGA conditions by a two-step mechanism. In the first step between 180 °C and 250 °C isopropylisocyanate (C3H7NCO) separates by degradation of diisopropylurea (DiPrU) in the side chain. The thermally stable residue represents the copolymer of methacryl-isopropylamide with St, which decompose by one-step mechanism between 280 °C and 450 °C

The multiphase and magnetized neutral hydrogen seen by LOFAR

Faraday tomography of polarimetric observations at low frequency in the radio is a unique tool for studying the structure of the magneto-ionic diffuse interstellar medium (ISM) based on Faraday depth. LOFAR data below 200 MHz have revealed a plethora of features in polarization, whose origin remains unknown. Previous studies have highlighted the remarkable association of such features with tracers of the magnetized-neutral ISM, such as interstellar dust and atomic hydrogen (HI). However, the physical conditions responsible for the correlation between magneto-ionic and neutral media have not been clarified yet. In this Letter we further investigate the correlation between LOFAR data and the HI spectroscopic observations at 21 cm from the Effelsberg-Bonn HI Survey (EBHIS). We focus on the multiphase properties of the HI gas. We present the first statistical study on the morphological correlation between LOFAR tomographic data and the cold (CNM), lukewarm (LNM), and warm (WNM) neutral medium HI phases. We use the Regularized Optimization for Hyper-Spectral Analysis approach to decompose the HI phases based on a Gaussian decomposition of the HI spectra. We study four fields of view - Fields 3C196, A, B, and C - and find, in at least the first two, a significant correlation between the LOFAR and EBHIS data using the histograms of oriented gradients (HOG) feature. The absence of a correlation in Fields B and C is caused by a low signal-to- noise ratio in polarization. The observed HOG correlation in Fields 3C196 and A is associated with all HI phases and it is surprisingly dominant in the CNM and LNM phases. We discuss possible mechanisms that would explain the correlation between CNM, LNM, and WNM with polarized emission at Faraday depths up to 10 rad m-2. Our results show how the complex structure of the ionic medium seen by the LOFAR tomographic data is tightly related to phase transition in the diffuse and magnetized neutral ISM traced by HI spectroscopic data

New generalized fuzzy metrics and fixed point theorem in fuzzy metric space

In this paper, in fuzzy metric spaces (in the sense of Kramosil and Michalek (Kibernetika 11:336-344, 1957)) we introduce the concept of a generalized fuzzy metric which is the extension of a fuzzy metric. First, inspired by the ideas of Grabiec (Fuzzy Sets Syst. 125:385-389, 1989), we define a new G-contraction of Banach type with respect to this generalized fuzzy metric, which is a generalization of the contraction of Banach type (introduced by M Grabiec). Next, inspired by the ideas of Gregori and Sapena (Fuzzy Sets Syst. 125:245-252, 2002), we define a new GV-contraction of Banach type with respect to this generalized fuzzy metric, which is a generalization of the contraction of Banach type (introduced by V Gregori and A Sapena). Moreover, we provide the condition guaranteeing the existence of a fixed point for these single-valued contractions. Next, we show that the generalized pseudodistance J:X×X→[0,∞) (introduced by Włodarczyk and Plebaniak (Appl. Math. Lett. 24:325-328, 2011)) may generate some generalized fuzzy metric NJ on X. The paper includes also the comparison of our results with those existing in the literature

Therapist Adherence in the Strong Without Anorexia Nervosa (SWAN) Study: A Randomized Controlled Trial of Three Treatments for Adults with Anorexia Nervosa

The Authors. International Journal of Eating Disorders Published by Wiley Periodicals, Inc. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Objective: To develop a psychotherapy rating scale to measure therapist adherence in the Strong Without Anorexia Nervosa (SWAN) study, a multi-center randomized controlled trial comparing three different psychological treatments for adults with anorexia nervosa. The three treatments under investigation were Enhanced Cognitive Behavioural Therapy (CBT-E), the Maudsley Anorexia Nervosa Treatment for Adults (MANTRA), and Specialist Supportive Clinical Management (SSCM). Method: The SWAN Psychotherapy Rating Scale (SWAN-PRS) was developed, after consultation with the developers of the treatments, and refined. Using the SWANPRS, two independent raters initially rated 48 audiotapes of treatment sessions to yield inter-rater reliability data. One rater proceeded to rate a total of 98 audiotapes from 64 trial participants. Results: The SWAN-PRS demonstrated sound psychometric properties, and was considered a reliable measure of therapist adherence. The three treatments were highly distinguishable by independent raters, with therapists demonstrating significantly more behaviors consistent with the actual allocated treatment compared to the other two treatment modalities. There were no significant site differences in therapist adherence observed. Discussion: The findings provide support for the internal validity of the SWAN study. The SWAN-PRS was deemed suitable for use in other trials involving CBT-E, MANTRA, or SSCM. VC 2015 The Authors. International Journal of Eating Disorders Published by Wiley Periodicals, Inc

Structure in the Magnetic Field of the Milky Way Disk and Halo traced by Faraday Rotation

Magnetic fields in the ionized medium of the disk and halo of the Milky Way impose Faraday rotation on linearly polarized radio emission. We compare two surveys mapping the Galactic Faraday rotation, one showing the rotation measures of extragalactic sources seen through the Galaxy (from Hutschenreuter et al 2022), and one showing the Faraday depth of the diffuse Galactic synchrotron emission from the Global Magneto-Ionic Medium Survey. Comparing the two data sets in 5deg x 10deg bins shows good agreement at intermediate latitudes, 10 < |b| < 50 deg, and little correlation between them at lower and higher latitudes. Where they agree, both tracers show clear patterns as a function of Galactic longitude: in the Northern Hemisphere a strong sin(2 x longitude) pattern, and in the Southern hemisphere a sin(longitude + pi) pattern. Pulsars with height above or below the plane |z| > 300 pc show similar longitude dependence in their rotation measures. Nearby non-thermal structures show rotation measure shadows as does the Orion-Eridanus superbubble. We describe families of dynamo models that could explain the observed patterns in the two hemispheres. We suggest that a field reversal, known to cross the plane a few hundred pc inside the solar circle, could shift to positive z with increasing Galactic radius to explain the sin(2xlongitude) pattern in the Northern Hemisphere. Correlation shows that rotation measures from extragalactic sources are one to two times the corresponding rotation measure of the diffuse emission, implying Faraday complexity along some lines of sight, especially in the Southern hemisphere.Comment: 37 pages, 26 figures, Ap. J. accepte

Fiscal Multipliers and Public Debt Dynamics in Consolidations

The success of a consolidation in reducing the debt ratio depends crucially on the value of the multiplier, which measures the impact of consolidation on growth, and on the reaction of sovereign yields to such a consolidation. We present a theoretical framework that formalizes the re spo nse of the public debt ratio to fiscal consolidations in relation to the value of fiscal multipliers, the starting debt level and the cyclical elasticity of the budget balance. We also assess the role of markets confidence to fiscal consolidations under al ternative scenarios. We find that with high levels of public debt and sizeable fiscal multipliers , debt ratios are likely to increase in the short term in response to fiscal consolidations. Hence, the typical horizon for a consolidation during crises episo des to reduce the debt ratio is two - three years , although this horizon depends critically on the size and persistence of fiscal multipliers and the reaction of financial markets. Anyway, such undesired debt responses are mainly short - lived. This effect is very unlikely in non - crisis times, as it requires a number of conditions difficult to observe at the same time , especially high fiscal multipliers

Faraday tomography of LoTSS-DR2 data: I. Faraday moments in the high-latitude outer Galaxy and revealing Loop III in polarisation

Interstellar matter and star formatio