Glass‐transition temperature determination by microhardness in norbornene‐ethylene copolymers

Vickers microhardness as a function of temperature was determined in a series of norbornene‐ethylene copolymers synthesized with a metallocene catalyst. The norbornene content in the samples ranges from 31 to 62 mol %, and all of them were found to be amorphous. The possibility of studying the glass‐transition temperature by plotting the microhardness‐temperature dependencies is discussed in addition to the limits and the reliability of the suggested method. Moreover, a linear dependency between microhardness at different temperatures and glass‐transition temperature was established. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3666–3671, 2003     

The triglyceride composition of linseed oil

The triglyceride composition of linseed oils obtained under different ecological conditions and having different fatty acid compositions was determined by a combination of several chromatographic techniques. The triglyceride mixture was first separated in 8 fractions of different polarity by reversed-phase paper chromatography. Each glyceride fraction was then separated in a partition chromatographic system as the triglyceride coordination complexes with silver ions into individual compounds. The fatty acid compositions of the original oil, single glyceride fractions, and individual triglycerides were determined by gas-liquid chromatography. The molar ratio between the two neighboring glyceride fractions was determined by relating the fatty acid composition of each fraction to the fatty acid composition of their sum. The triglyceride composition of the total oil was then calculated from these results. The presence of 18–19 triglycerides was ascertained in the samples studied, and the molar concentration of each glyceride was estimated. Linseed oil contains only triunsaturated and monosaturated-diunsaturated triglycerides. Within each of these types the fatty acid distribution is close to random. At the same time, the content of some triglycerides departed regularly from a random pattern. A method for calculation of linseed oil triglyceride composition from the fatty acid composition is given. The same general pattern of glyceride formation in linseed is followed regardless of ecological conditions; therefore, the qualitative and quantitative triglyceride composition reflects the differences in fatty acid composition of linseed oil.     

An online color naming experiment in Russian using Munsell color samples

Russian color naming was explored in a web‐based experiment. The purpose was 3‐fold: to examine (1) CIELAB coordinates of centroids for 12 Russian basic color terms (BCTs), including 2 Russian terms for “blue”, sinij “dark blue”, and goluboj “light blue”, and compare these with coordinates for the 11 English BCTs obtained in earlier studies; (2) frequent nonBCTs; and (3) gender differences in color naming. Native Russian speakers participated in the experiment using an unconstrained color‐naming method. Each participant named 20 colors, selected from 600 colors densely sampling the Munsell Color Solid. Color names and response times of typing onset were registered. Several deviations between centroids of the Russian and English BCTs were found. The 2 “Russian blues”, as expected, divided the BLUE area along the lightness dimension; their centroids deviated from a centroid of English blue. Further minor departures were found between centroids of Russian and English counterparts of “brown” and “red”. The Russian color inventory confirmed the linguistic refinement of the PURPLE area, with high frequencies of nonBCTs. In addition, Russian speakers revealed elaborated naming strategies and use of a rich inventory of nonBCTs. Elicitation frequencies of the 12 BCTs were comparable for both genders; however, linguistic segmentation of color space, employing a synthetic observer, revealed gender differences in naming colors, with more refined naming of the “warm” colors from females. We conclude that, along with universal perceptual factors, that govern categorical partition of color space, Russian speakers’ color naming reflects language‐specific factors, supporting the weak relativity hypothesis.     

Optical determination of thallium(I) and cesium(I) with a fluorogenic calix[4]arenebis(crown-6 ether) containing one pendent dansyl group

A fluorogenic derivative of 1,3-alternate calix[4]arenebis(crown-6) (1) containing a dansyl group in the proton-ionizable side arm has been employed in selective sensing of Tl+ and Cs+ at low concentration levels in MeCN-H2O (1:1) mixed solvent. Optical recognition of these two metal cations by 1 occurs in contrasting modes. On the basis of the results of fluorescence, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), and 1H NMR studies, Tl+ and Cs+ react with 1 via formation of 1:1 complexes that differ in coordination arrangement around the metal ion.     

Synthesis of high-surface-area complex zirconium phosphates via mechanochemical activation route

 High-power ball mill activation of the mixture of hydrated zirconium and lanthanum salts (oxonitrates, oxochlorides) with ammonium phosphate followed by hydrothermal treatment at temperatures not exceeding 200°C and a nearly neutral pH was found to yield crystalline dispersed phase of a cubic NH₄Zr₂(PO₄)₃ type along with admixtures of disordered orthorhombic compounds of a zirconium orthophosphate type. In the same conditions and at the same Zr/P ratio, hydrothermal treatment of gels obtained by reacting mixed zirconium and lanthanum nitrates solutions with ammonium phosphates yields no crystalline products, and only treatment in acid media generates a phase of the α-ZrPO₄(OH) type coexisting with the NH₄Zr₂(PO₄)₃ phase if polyethylene oxide is present. X-ray powder diffraction, transmission electron microscopy, ³¹MAS-NMR, FTIRS and thermal analysis were applied to elucidate factors affecting crystallization of complex zirconium phosphates in the hydrothermal conditions. The most essential factor appears to be generation of some nuclei of zirconium phosphates under high pressures developed in the course of mixed solids mechanical activation. These nuclei are embedded into matrix of such well-crystallized solid products as ammonium nitrate or chloride. Hence, metastable cubic or orthorhombic structure of the phases obtained via mechanical activation route can be assigned to the nuclei-matrix orientation relationship. Due to easily scaled-up synthesis procedure, these results appear to be very promising for manufacturing of dispersed framework zirconium phosphates as acid catalysts or fast proton conductors. Received: 18 November 1998 / Reviewed and accepted: 2 December 1998     

Complex Transposon Insertion as a Novel Cause of Pompe Disease

Pompe disease (OMIM#232300) is an autosomal recessive lysosomal storage disorder caused by mutations in the GAA gene. According to public mutation databases, more than 679 pathogenic variants have been described in GAA, none of which are associated with mobile genetic elements. In this article, we report a novel molecular genetic cause of Pompe disease, which could be hardly detected using routine molecular genetic analysis. Whole genome sequencing followed by comprehensive functional analysis allowed us to discover and characterize a complex mobile genetic element insertion deep in the intron 15 of the GAA gene in a patient with infantile onset Pompe disease.     

Noble metal ion sorption by pyridyl and bipyridyl group‐containing chelating polymers

A series of eighteen 4‐vinylpyridine and 4‐methyl‐4′‐vinylbipyridine copolymers with different crosslinkers was examined as sorbents for the noble metal ions of Ag(I), Au(III), Pd(II), and Pt(II) from aqueous solutions. The chelating polymers possess appreciable sorption selectivity for Au(III) over Ag(I) and for Pd(II) over Pt(II). Binding abilities of the copolymers toward the noble metal ions vary as the identity of the chelating heterocyclic amine moiety and the structure of the crosslinkers are altered. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 207–213, 2001     

The Application of Different Physical Approaches for The Description of Structural Features in Wheat and Rye Starches. A DSC Study

Starches isolated from wheat (Rapoport's variety) at different stages of maturation and from completely maturated rye (Viatka‐2 variety) were investigated in excess of water and in 0.6 M KCl using high sensitivity differential scanning microcalorimetry (HSDSC). Applying some physico‐chemical approaches, the starch polymorphous structure, the thickness of the crystalline lamellae and the thermodynamic parameters characterizing their surface faces were determined. It has been established that wheat and rye starches belong to the A‐type starches. It is suggested that during biosynthesis of granules the formation of the A‐type structure is accompanied by an accumulation of crystal defects. This process leads to a decrease in the melting temperature of starches.     

Index Criteria for Differential Algebraic Equations Arising from Linear-Quadratic Optimal Control Problems

The index of DAE systems arising from linear quadratic optimal control problems is considered. Necessary and sufficient conditions ensuring regularity with tractability index one are proved. Then, it is shown that if the control problem DAE is regular with index one and if the leading term of the DAE to be controlled is given by one full-column-rank and one full-row-rank matrix, then it has a Hamiltonian inherent explicit ODE. For problems with regular index zero or index one DAEs to be controlled, the DAE of the control problem is shown to be regular with tractability index one or three, depending on whether the control coefficient R is singular. 2000 Mathematics Subject Classification. 49N10, 49J15, 34A09. Supported by the DFG research center MATHEON in Berlin. This work was partially supported by the Russian Fundamental Research Foundation Project Nos. 02-01-00351 and 06-01-00296.     

Effect of Microstructure and Hydrogen Pores on the Mechanical Behavior of an Al7%Si0.3%Mg Alloy Studied by a Combined Phase‐Field and Micromechanical Approach

A combination of the phase‐field method for the simulation of the microstructure evolution during solidification with subsequent finite element simulation of fracture appearance in the final solidification structure is proposed for the prediction of the mechanical behavior of Al? Si based casting alloys, including the effect of solidification porosity caused by hydrogen. Metallographic investigations and computer tomographic observations of the as cast microstructure of an Al7%Si0.3%Mg alloy together with the data obtained from mechanical tensile testing are used to compare and validate the simulation results to demonstrate the capabilities as well as current limitations in micromechanical modeling of void containing materials. In micromechanical simulations with the element elimination technique (EET) it is shown that porosity influences the crack path as well as crack propagation by connecting the pores. In the eutectic microstructure without porosity, failure starts to develop in silicon lamellae and proceeds in the ductile matrix. However, in the presence of pores fracture also initiates in silicon, and in the later stages of loading, porosity affects the path of the crack and results in additional crack nucleation, and thus, these pores also influence crack propagation in the matrix.