X-ray characterization of starch-based solid foams

Wide- and small-angle X-ray scattering (WAXS and SAXS) and X-ray microtomography were used to study the structure of brittle, solid foams made by extrusion of whole grain barley flour and additional whey protein isolate (WPI) and polydextrose (PD). The structure of the extrudates was described in a coarse way from nano- to microscale, and the effects of additives were discussed. The additives were observed to affect the structure in many scales, for instance, by inducing differences in the crystal structure of starch and in the microscale pore structure observed with both SAXS and X-ray microtomography. The most significant effects were introduced by WPI, but these were highly reduced in the presence of PD. Differences were also seen in lamellar structures of starch, which were probably formed due to retrogradation and observed with SAXS in powder samples soaked in water before the measurements.     

Self-assembling of star-like amphiphilic block copolymers with polyelectrolyte blocks. Effect of pH

The self-assembling behaviour of a four-arm amphiphilic star block copolymer, (PMMA₇₃-b-PAA₁₄₃)₄, with poly(methyl methacrylate) inner blocks and poly(acrylic acid) outer blocks in ratio 1:2 (PMMA:PAA) has been investigated in aqueous solutions as a function of pH by dynamic light scattering and cryo-transmission electron microscopy. At low pH (pH ≤ 5) the amphiphile forms in the presence of salt both spherical and worm-like micellar aggregates that coexist in solution. At high pH (pH > 12) the solution contains mainly spherical micelles and a small number of larger aggregates that have ‘pearl-necklace’ structure, indicating the disintegration of the worm-like species. In addition to the experiments, computer simulations of the four-arm amphiphilic star block copolymer with the same ratio of the blocks as above were conducted using a coarse-grained model. The simulations predict the formation of the worm-like micellar aggregates at low pH and the spherical ones at high pH. The changes in the morphology of the aggregates are related to the higher degree of ionization of poly(acrylic acid) blocks at high pH and to the swelling of the corona of the micelles by the higher osmotic pressure due to trapped counterions.     

Error analysis of a Galerkin method to solve the forward problem in MEG using the boundary element method

Sources of brain activity, e.g. epileptic foci, can be localized with Magnetoencephalography (MEG) measurements by recording the magnetic field outside the head. For a successful surgery a very high localization accuracy is needed. The most often used conductor model in the source localization is an analytic sphere, which is not always adequate, and thus a realistically shaped conductor model is needed. In this paper we examine a Galerkin method with linear basis functions to solve the forward problem in MEG using the boundary element method. Its accuracy is compared to the collocation method with constant and linear basis functions. The accuracies are determined for a unit sphere for which analytic solutions are available. The Galerkin method gives a clear improvement in the accuracy of the forward problem especially for the tangential component of the magnetic field. At realistic MEG measurement distances from the brain the Galerkin method reaches a given accuracy with lower computational costs than the collocation methods starting from a few hundreds of unknowns. With larger meshes the difference for the Galerkin method increases significantly.     

Prevalence and diversity of Clostridium botulinum types A, B, E and F in honey produced in the Nordic countries

A total of 294 honey samples produced in Denmark, Norway and Sweden were studied for the presence of Clostridium botulinum types A, B, E and F by using a multiplex-PCR method. The samples consisted of honeycombs taken directly from beehives, and extracted honey representing several hives or apiaries. The prevalence of C. botulinum showed a significant variation between Denmark, Norway and Sweden, the proportions of positive samples being 26%, 10% and 2%, respectively. The major serotype detected was type B. When analysed with pulsed-field gel electrophoresis (PFGE) using restriction enzyme SacII, the 24 strains isolated produced eight different PFGE patterns. At a similarity level of 95%, four clusters were produced, three of which contained 20 of the 24 analysed strains. One of the clusters included isolates from both Denmark and Norway.     

Expression of ion transport-associated proteins in human efferent and epididymal ducts

Appropriate intraluminal microenvironment in the epididymis is essential for maturation of sperm. To clarify whether the anion transporters SLC26A2, SLC26A6, SLC26A7, and SLC26A8 might participate in generating this proper intraluminal milieu, we studied the localization of these proteins in the human efferent and the epididymal ducts by immunohistochemistry. In addition, immunohistochemistry of several SLC26-interacting proteins was performed: the Na(+)/H(+) exchanger 3 (NHE3), the Cl(-) channel cystic fibrosis transmembrane conductance regulator (CFTR), the proton pump V-ATPase, their regulator Na(+)/H(+) exchanger regulating factor 1 (NHERF-1), and carbonic anhydrase II (CAII). Our results show that SLC26A6, CFTR, NHE3, and NHERF-1 are co-expressed on the apical side of the nonciliated cells, and SLC26A2 appears in the cilia of the ciliated cells in the human efferent ducts. In the epididymal ducts, SLC26A6, CFTR, NHERF-1, CAII, and V-ATPase (B and E subunits) were co-localized to the apical mitochondria rich cells, while SLC26A7 was expressed in a subgroup of basal cells. SLC26A8 was not found in the structures studied. This is the first study describing the localization of SLC26A2, A6 and A7, and NHERF-1 in the efferent and the epididymal ducts. Immunolocalization of human CFTR, NHE3, CAII, and V-ATPase in these structures differs partly from previous reports from rodents. Our findings suggest roles for these proteins in male fertility, either independently or through interaction and reciprocal regulation with co-localized proteins shown to affect fertility, when disrupted.     

Topology estimation method for telecommunication networks

In order to resolve the traditional limited lifetime problem, energy harvesting technology has been introduced into wireless sensor network (WSN) in recent years, engendering a new kind of network which is called energy harvesting wireless sensor network (EHWSN). In EHWSNs, besides the traditional issues, such as energy consumption, energy equilibrium, transmission efficiency, etc., there are still new challenges, such as how to utilize harvested energy efficiently and how to make more sensor nodes so as to achieve unlimited lifetime under actual situation. In this paper, inspired by slime mold Physarum polycephalum, a novel bionic routing protocol, abbreviated as EHPRP, is proposed for EHWSNs to address above problems without predicting harvestable energy value. Three distributed routing algorithms with low algorithm complexity are proposed which would prominently reduce the processing delay and conserve energy. Furthermore, the mathematic theoretical analysis is made to prove the stability of EHPRP routing strategy. Finally, simulation results present that, compared with other typical algorithms, EHPRP consumes less energy, always making the whole network obtain an unlimited lifetime, and displaying more uniform network energy distribution under different workload conditions.