Content of uranium in urine of uranium miners as a tool for estimation of intakes of long-lived alpha radionuclides

Uranium in the urine of 10 uranium miners (hewers), 27 members of general population and 11 family members of miners was determined by the High-Resolution ICP-MS method. Concentration of uranium in urine of the miners was converted to daily excretion of (238)U under the assumption that the daily excretion of urine is 2 l and compared with the modelled excretion of (238)U. Daily excretion of (238)U was modelled using input data from personal dosemeters from a component for measurement of intake of long-lived alpha radionuclides. A reasonable agreement between evaluated and measured values was found. The uncertainty of inhalation intakes, derived from measurements of filters from personal dosemeters, and uncertainty of concentration of uranium in urine are discussed.     

Disorder effect in the transmission spectra of a noncompact single layer of dielectric spheres derived from microwave spectroscopy

Single layers of dielectric spheres are an interesting system to study from the fundamental and applied points of view. In this paper we present a systematic study of the influence of structural disorder on the transmission spectra of arrangements of spheres of different compactness. Glass sphere (ε=7) planes were built and their transmission spectra in the microwave range measured. Transmission behavior of this system is highly tolerant to disorder. Even in completely disordered arrangements, there is a highly rejected band with the dips of the spectrum observable. These results suggest that the collective modes of the sphere planes are formed by weakly coupled Mie modes of the individual spheres, and this coupling is governed by the average distance among the spheres. Disorder tolerance allows simpler fabrication procedures where the position of the spheres does not need to be precisely controlled.     

Between ‘Platial’ Imaginations and Spatial Rationalities: Navigating Justice and Law in the Low Countries

During the past two decades, landscape has frequently been conceptualized as a distancing way of seeing space. This conceptualization is normally traced back to the rise of capitalism and various modes of artistic representation, notably in the early modern Netherlands or the northern Low Countries. Yet recent scholarly interventions have asserted that landscape in the Low Countries and elsewhere in Europe was more than a distant scenery or an artistic mode of representation. Landscape also animated practices and ideologies of political representation, platial justice and custom. The platial notion of landscape and related concepts in the northern Low Countries around 1600 is focused upon, bringing out the intimate relationships between land, water and diverging ideals and practices of justice. It is argued that artistic landscape representation provided ways to reflect upon spatio-political developments in the Netherlands. Finally, there is a brief consideration of how these theoretical and historical issues resonate with modern thinking about landscape in physical planning.     

Premixed hydrogen-air combustion system for fuel cell systems

The advance of efficient hydrogen-air combustion systems has increasingly become of interest in the framework of the development of fuel cell systems, especially for the automotive sector. Therefore, compact modulating systems are required, with the additional demand of low emissions, to be integrated in a fuel cell system. A modulating combustion system based on combustion within inert porous media and an integrated heat exchanger has been developed and investigated. The system is able to handle premixed combustion of lean H₂/air mixtures at a surface load range of 1075 kW/m²-2150 kW/m², and a global equivalence ratio of ?=0.5. The special hydrogen-air mixing concept eliminates the risk of flame flashback and enables operation with very low NO_x emissions.     

Lifetime Assessment of Load‐Bearing Polymer Glasses: An Analytical Framework for Ductile Failure

The most widespread application of polymers in structural applications is their use as pipe material for e.g., gas distribution systems. Pipes have a design lifetime of typically 50 years, which rules out real‐time lifetime assessment methods. Here, an engineering approach is presented, which makes it possible to predict long‐term ductile failure of loaded glassy polymers based on short‐term tests. The approach is based upon the hypothesis that failure is governed by accumulation of plastic deformation up to a critical strain. A pressure‐modified Eyring relation is employed to calculate the accumulation of plastic strain for any simple loading geometry. It is demonstrated that the approach can produce accurate quantitative time‐to‐failure predictions for loaded PC specimens and uPVC pipe segments.

     

Increasing the thermostability of sucrose phosphorylase by a combination of sequence- and structure-based mutagenesis

Sucrose phosphorylase is a promising biocatalyst for the glycosylation of a wide variety of acceptor molecules, but its low thermostability is a serious drawback for industrial applications. In this work, the stability of the enzyme from Bifidobacterium adolescentis has been significantly improved by a combination of smart and rational mutagenesis. The former consists of substituting the most flexible residues with amino acids that occur more frequently at the corresponding positions in related sequences, while the latter is based on a careful inspection of the enzyme's crystal structure to promote electrostatic interactions. In this way, a variant enzyme could be created that contains six mutations and whose half-life at the industrially relevant temperature of 60 °C has more than doubled compared with the wild-type enzyme. An increased stability in the presence of organic co-solvents could also be observed, although these effects were most noticeable at low temperatures.     

<Emphasis Type="Italic">N</Emphasis>-Acylated Bacteriohopanehexol-Mannosamides from the Thermophilic Bacterium <Emphasis Type="Italic">Alicyclobacillus acidoterrestris</Emphasis>

Identification of molecular species of various N-acylated bacteriohopanehexol-mannosamides from the thermophilic bacterium Alicyclobacillus acidoterrestris by semipreparative HPLC and by RP-HPLC with ESI is described. We used triple-quadrupole type mass spectrometer, ¹H and ¹³C NMR for analyzing this complex lipid. CD spectra of two compounds (model compound—7-deoxy-d-glycero-d-allo-heptitol obtained by stereospecific synthesis, and an isolated derivative of hopane) were also measured and the absolute configuration of both compounds was determined. On the basis of all the above methods, we identified the full structure of a new class of bacteriohopanes, represented by various N-acylated bacteriohopanehexol-mannosamides.     

Periodic steady state analysis using shooting and wave-form-newton

This paper describes a method of determining the forced periodic steady state response of non-linear circuits. the method is closely related to the work of Aprille and Trick Proc. IEEE, 60 , 108-114 (1972) and also to the finite difference method for solving a boundary value problem. The new approach is a shooting method in the sense that in every iteration an initial value problem is solved. It is, however, also a relaxation method, because in every iteration a periodic wave-form is obtained. This is achieved by solving in each step a linear time-dependent differential equation whose solution can be easily transformed into a periodic solution satisfying this linear equation. Because the iteration takes place on wave-forms rather than initial values and every solution satisfies the boundary conditions, the method is robust. It will be shown that for a causal approximation of the time derivatives the iterated wave-forms are equal to those found using the finite difference methods.     

Development of a gel spinning process for high‐strength poly(ethylene oxide) fibers

This article describes a new gel‐spinning process for making high‐strength poly(ethylene oxide) (PEO) fibers. The PEO gel‐spinning process was enabled through an oligomer/polymer blend in place of conventional organic solvents, and the gelation and solvent‐like properties were investigated. A 92/8 wt% poly(ethylene glycol)/PEO gel exhibited a melting temperature around 45°C and was highly stretchable at room temperature. Some salient features of a gel‐spun PEO fiber with a draw ratio of 60 are tensile strength at break = 0.66 ± 0.04 GPa, Young's modulus = 4.3 ± 0.1 GPa, and a toughness corresponding to 117 MJ/m³. These numbers are significantly higher than those previously reported. Wide‐angle x‐ray diffraction of the high‐strength fibers showed good molecular orientation along the fiber direction. The results also demonstrate the potential of further improvement of mechanical properties. POLYM. ENG. SCI., 54:2839–2847, 2014. © 2014 Society of Plastics Engineers     

Evaluation of the Interaction between Phosphohistidine Analogues and Phosphotyrosine Binding Domains

We have investigated the interaction of peptides containing phosphohistidine analogues and their homologues with the prototypical phosphotyrosine binding SH2 domain from the eukaryotic cell signalling protein Grb2 by using a combination of isothermal titration calorimetry and a fluorescence anisotropy competition assay. These investigations demonstrated that the triazole class of phosphohistidine analogues are capable of binding too, suggesting that phosphohistidine could potentially be detected by this class of proteins in vivo.