Is air-drying of plant-based food at low temperature really favorable? A meta-analytical approach to ascorbic acid,total phenolic,and total flavonoid contents

The aim of this work was to review the studies that evaluated the effect of drying temperature on the content of ascorbic acid (AA), total phenolic (TPC), and total flavonoid contents (TFC) in fruits and vegetables, and quantify whether drying at 40 °C is more favorable than at higher temperatures. For the purpose of this study, AA, TPC, and TFC values for 40 °C were compared with those obtained at 50 °C, 60 °C, and 70–80 °C. A meta-analysis was performed using the weighted response ratio calculated for each experiment. Despite the fact that other variables significantly influenced the nutrient content in individual experiments, the meta-analysis provided a general view on the effect of air-drying temperature on the quality of plant-based food products from outcomes of various studies.     

Efficient encoding of texture coordinates guided by mesh geometry

In this paper, we investigate the possibilities of efficient encoding of UV coordinates associated with vertices of a triangle mesh. Since most parametrization schemes attempt to achieve at least some level of conformality, we exploit the similarity of the shapes of triangles in the mesh and in the parametrization. We propose two approaches building on this idea: first, applying a recently proposed generalization of the parallelogram predictor, using the inner angles of mesh triangles corresponding to the UV‐space triangles. Second, we propose an encoding method based on discrete Laplace operator, which also allows exploiting the information contained in the mesh geometry to efficiently encode the parametrization. Our experiments show that the proposed approach leads to savings of up to 3 bits per UV vertex, without loss of precision.     

Comparison of recent rubber-elasticity theories with biaxial stress-strain data: the slip-link theory of Edwards and Vilgis

The Edwards-Vilgis (EV) slip-link theory (1986) derives the elastic free energy of a rubber-like network model containing stable and sliding network junctions (crosslinks and slip-links) and predicts both low-strain softening and high-strain hardening. The four-parameter stress-strain relations calculated by the theory for geometrically different deformation modes up to high strains were tested experimentally using published biaxial stress-strain data on simple covalently crosslinked networks. For networks with low degrees of strain softening and low extensibilities, the experimental dependencies could be described rather well but, generally, a simultaneous satisfactory fit to uniaxial, pure shear and equibiaxial data was not obtained. Systematic experiment-theory deviations exceeding 10% were observed and some of the parameters had a tendency to assume values lying outside the reasonably expected range. The prediction of a pronounced maximum in the strain dependence of stress supported by slip-links seems to be a reason for the discrepancy. Also, modeling of the high-strain singularity in entropy is done in the EV theory using a rather simple approximation. As a result, the finite extensibility contribution to the stress of a slip-link-free network model becomes improbably high and significantly exceeds that following, at a given modulus and locking stretch, from the rigorously derived Langevin-statistics-based eight-chain-network elasticity theory of Arruda and Boyce.     

Activity of the Ni?CAl Mixed Oxides Prepared from Hydrotalcite-Like Precursors in the Oxidative Dehydrogenation of Ethane and Propane

The activity of Ni?CAl mixed oxides obtained by the thermal pre-treatment of Ni?CAl hydrotalcite-like precursors was studied in the ODH of ethane and propane. The activity of the Ni?CAl mixed oxide catalysts was studied with respect to (i) the role of Ni content and (ii) the role of temperature during Ni?CAl HTs thermal pre-treatment. The structure analysis and the activity of Ni?CAl mixed oxides were discussed in three groups; (A) the catalysts pre-treated at 500???C, (B) the catalysts pre-treated at 600???C and (C) the Ni2?CAl catalyst with constant Ni content pre-treated at 500?C900???C. Ni?CAl mixed oxides were active and selective catalysts in the ODH of ethane even at 450???C. On the other hand, the catalysts posses low selectivity to propene. It is supposed that the interaction of NiO with alumina phase plays the critical role in the active and selective catalysts. The Ni?CAl mixed oxides were characterized by XRD, H₂-TPR and diffuse reflectance spectroscopy.     

Synthesis, In vitro Antifungal and Antitumour Activity of Some Triorganotin(IV) N,C,N-Chelates

The in vitro antifungal activity of compounds 1-3 ({[(CH3)2NCH2]2C6H3}R2SnX; (where X=Cl, R=n-Bu for 1, X=Br, R=n-Bu for 2 and x=PF6, R=n=Bu for 3)) was estimated with the help of a modified microdilution format of the M27-A guidelines and was compared with in vitro activity of their diphenyltin(IV) analogues 4 and 5 (where X=Br, R=Ph for 4 and X=PF6, R=Ph for 5), and of drugs currently in clinical use (ketoconazole, fluconazole and amphotericin B). It was found that in coordinating solvents the more soluble derivative 2 is less active than the phenyl one (4), and compounds 1 and 3 are even inactive.In this paper, the in vitro antitumour activity of ionic diphenyltin(IV) complexes 4 and 5 against seven tumoural cell lines of human origin is also reported. The preparation and characterization (H1, C13 and Sn119 NMR spectroscopy and electrospray ionization mass spectrometry) of the novel compound 3 is mentioned too.     

Synthesis of defined polyhedral oligosilsesquioxane‐containing diblock and triblock methacrylate copolymers by atom transfer radical polymerization

Defined diblock and triblock copolymers composed of methyl methacrylate‐co‐glycidyl methacrylate block and 3‐{3,5,7,9,11,13,15‐hepta(2‐methylpropyl)‐pentacyclo[9.5.1.1^3,9.1^5,15.1^7,13]‐octasiloxan‐1‐yl}propyl methacrylate block(s), i.e., P(MMA‐co‐GMA)‐b‐PiBuPOSSMA and PiBuPOSSMA‐b‐P(MMA‐co‐GMA)‐b‐PiBuPOSSMA, were synthesized by atom transfer radical polymerization (ATRP). First, monofunctional and bifunctional P(MMA‐co‐GMA) copolymers were synthesized by ATRP. Subsequently, these copolymers were successfully used as macroinitiators for ATRP of POSS‐containing methacrylate monomer. The process showed high initiation efficiency of macroinitiators and led to products with low dispersity. The synthesized block copolymers were characterized by size exclusion chromatography, ¹H‐NMR spectroscopy and their glass transition temperatures were determined by differential scanning calorimetry. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Mixtures of l-Amino Acids as Reaction Medium for Formation of Iron Nanoparticles: The Order of Addition into a Ferrous Salt Solution Matters

Owing to Mössbauer spectroscopy, an advanced characterization technique for iron-containing materials, the present study reveals previously unknown possibilities using l-amino acids for the generation of magnetic particles. Based on our results, a simple choice of the order of l-amino acids addition into a reaction mixture containing ferrous ions leads to either superparamagnetic ferric oxide/oxyhydroxide particles, or magnetically strong Fe⁰-Fe₂O₃/FeOOH core-shell particles after chemical reduction. Conversely, when ferric salts are employed with the addition of selected l-amino acids, only Fe⁰-Fe₂O₃/FeOOH core-shell particles are observed, regardless of the addition order. We explain this phenomenon by a specific transient/intermediate complex formation between Fe²⁺ and l-glutamic acid. This type of complexation prevents ferrous ions from spontaneous oxidation in solutions with full air access. Moreover, due to surface-enhanced Raman scattering spectroscopy we show that the functional groups of l-amino acids are not destroyed during the borohydride-induced reduction. These functionalities can be further exploited for (i) attachment of l-amino acids to the as-prepared magnetic particles, and (ii) for targeted bio- and/or environmental applications where the surface chemistry needs to be tailored and directed toward biocompatible species.     

Thermomechanical Properties of Polypropylene-Based Lightweight Composites Modeled on the Mesoscale

A waste-based particle polymer composite (WPPCs) made of foam glass and polypropylene was developed as a low-cost construction material. Thermomechanical properties of the composite, including creep properties of WPPC and polypropylene binder, were examined. By adding a relatively small amount of polypropylene to foam glass (about 2:8 in volume parts), the maximum bearing capacity at room temperature of the composite increased from 1.9 (pure foam glass) to 15 MPa. A significant creep strain accumulated during compressive loading of WPPC (5 MPa) in the first 2000 s at elevated temperatures (40, 60 °C). In the study, Kafka’s mesomechanical model was used to simulate creep strain changes in time for various temperatures. The applicability of Kafka’s mesomechanical model for simulating creep properties of the studied composite material was demonstrated.     

Effect of catalyst composition on the selectivity of competitive hydrogenations of mono-olefinic reactants in the liquid state

The effect of the amount of platinum and the type of the carrier on the selectivity for competitive hydrogenation of 2-methyl-3-butene-2-ol and hex-l-ene in methanol on platinum carrier catalysts has been studied. The effect of the type of the active component and carrier on the selectivity for competitive hydrogenation of 2-methyl-3-butene-2-ol and 2-phenylpropene in methanol and cyclohexane on various types of catalyst has also been investigated. Selectivity decreased with increasing amounts of platinum on the carrier and also with decreasing polarity of the carrier. The change in selectivity was greatest for a change in the active (metal) component of the catalysts; being in most cases several times higher in cyclohexane compared with methanol.     

Gelation in the curing of epoxy resins with anhydrides

Summary The statistical theory of branching processes has been used in an analysis of gelation in the system diepoxide-cyclic anhydride-tert.-amine in step and initiated reaction mechanisms. Experimental data indicate that critical conversion depends on the concentration of tert.-amine, which suggests that a mechanism with initiation is operative.