The utilization of sodium in sodium zeolite A by broilers

Two identical experiments were conducted with 1-d-old broiler chicks to determine whether the Na in sodium zeolite A (SZA) was utilizable. Three male and three female chicks were randomly assigned to each of eight replicate pens per treatment. A corn-soybean meal basal diet was formulated to contain supplemental levels of 0, .02, .04, .06, .08, and .16% Na from either SZA or NaCl. The diets were isocaloric and isonitrogenous. The Cl level within each dietary Na level was kept constant. Feed and deionized water were offered for ad libitum consumption throughout each 21-d experiments. In both experiments, broiler body weight was increased with each addition of Na from either NaCl or SZA. In Experiment 1, the addition of Na, whether from NaCl or SZA, resulted in an improvement in feed consumption and feed conversion compared with birds fed the control diet. In Experiment 2, body weights of birds fed .04 to .08% Na from SZA were heavier than those fed the same levels from NaCl. Overall the addition of Na from SZA or NaCl resulted in an improvement in body weight, increased feed consumption, and improved feed conversion. Data from these experiments indicated that the Na in SZA was able to be utilized by broilers as efficiently as the Na from NaCl.     

Implementation of the periodic boundary condition in thefinite-difference time-domain algorithm for FSS structures

A method for implementing the general Floquet boundary condition in the finite-difference time-domain algorithm (FDTD) is presented. The Floquet type of phase shift boundary condition is incorporated into the time-domain analysis by illuminating the structure with a combination of sine and cosine excitations to generate a phasor representation of the solution at each time step. With this approach, the characteristics of periodic structures comprised of arbitrarily shaped inhomogeneous geometries can be computed for an arbitrary angle of incidence. Theoretical results are compared for various planar frequency selective surfaces (FSS) and for one with a three-dimensional element, e.g., a thick, double, concentric square loop     

Effects of prior exercise on exercise-induced arterial hypoxemia in young women

Insulin-like growth factor binding proteins (IGFBP) proteases have been proposed to be involved in changes of serum IGFBP pattern during pregnancy. IGFBP-4 and -5 are degraded specifically by proteases in pregnancy serum in vitro, whereas IGFBP-3 proteolytic activity was also detected in nonpregnancy serum. To identify and characterize IGFBP proteases, human pregnancy serum was fractionated by size exclusion chromatography revealing IGFBP-4 protease activities in fractions coeluting with proteins of approximately 600-kDa and 50- to 100-kDa molecular mass. In both fractions, a predominant 50-kDa gelatinase was found, suggesting that parts of the gelatinase activity might aggregate or are complexed with other proteins forming a higher molecular complex. Hydroxyapatite chromatography and chromatofocusing of the 50- to 100-kDa serum fraction showed that the IGFBP-4 protease and the 50-kDa gelatinase activity were copurified. When the 50-kDa gelatinase-containing band was excised from the polyacrylamide gel, it exhibited IGFBP-4 proteolytic activity, resulting in the formation of 17- and 10-kDa fragments. [125I] IGFBP substrate zymography combined with fragment blotting showed that the 1,10-phenanthroline-sensitive 50-kDa protease activity purified by chromatofocusing also cleaved IGFBP-3 and -5. Other proteases detected in pregnancy serum fractions with Mr estimates of 79-, 30-, and 22-kDa degraded IGFBP-3 and -5 but not IGFBP-4. [125I] IGFBP-5 substrate zymography revealed that the 30-kDa IGFBP protease was inhibited by serine protease inhibitors. Whereas 1,10-phenanthroline inhibited the IGFBP proteolytic activity in the solution assay, serine protease inhibitors failed to affect proteolysis, indicating the predominant contribution of the metalloproteinase to IGFBP proteolysis. Tissue inhibitors of matrix metalloproteinases-1 and -2 revealed weak or no inhibition of IGFBP-4 and -5 proteolytic activity, whereas a hydroxamic acid-based inhibitor, potentially inhibiting disintegrin metalloproteases, completely prevented the proteolysis of IGFBPs. Whereas no specific immunoreactivity of the 50-kDa protein with antimatrix metalloproteinase-1, -2, -3, -9, or -13 antibodies was observed, antidisintegrin domain-specific antibodies bound to the 50-kDa gelatinase. These studies provide the first direct biochemical evidence that human pregnancy serum contains a 50-kDa IGFBP protease with properties of a soluble disintegrin metalloproteinase that appears to be potentially involved in regulating IGF bioavailability for placental and fetal growth.     

Efficient wave propagation simulation on quadtree meshes using SBFEM with reduced modal basis

We apply a combination of the transient scaled boundary finite element method (SBFEM) and quadtree‐based discretization to model dynamic problems at high frequencies. We demonstrate that the current formulation of the SBFEM for dynamics tends to require more degrees of freedom than a corresponding spectral element discretization when dealing with smooth problems on regular domains. Thus, we improve the efficiency of the SBFEM by proposing a novel approach to reduce the number of auxiliary variables for transient analyses. Based on this improved SBFEM, we present a modified meshing procedure, which creates a quadtree mesh purely based on the geometry and allows arbitrary sizes and orders of elements, as well as an arbitrary number of different materials. The discretization of each subdomain is created automatically based on material parameters and the highest frequency of interest. The transition between regions of different properties is straightforward when using the SBFEM. The proposed approach is applied to image‐based analysis with a particular focus on geological models. Copyright © 2016 John Wiley & Sons, Ltd.     

Degenerate Quantum Gases in Microgravity

Clouds of ultra-cold atoms and especially Bose–Einstein condensates (BEC) provide a source for coherent matter-waves in numerous earth bound experiments. Analogous to optical interferometry, matter-wave interferometers can be used for precision measurements allowing for a sensitivity orders of magnitude above their optical counterparts. However, in some respects the presence of gravitational forces in the lab limits experimental possibilities. In this article, we report about a compact and robust experiment generating Bose–Einstein condensates in the drop tower facility in Bremen, Germany. We also present the progress of building the succeeding experiment in which a two species atom interferometer will be implemented to test the weak equivalence principle with quantum matter.     

Prediction of Martensite Start Temperature for Lightweight Fe-Mn-Al-C Steels

A tailor-made thermodynamic database of the Fe-Mn-Al-C system was developed using the CALPHAD approach. The database enables predicting phase equilibria and thereby assessing the resulting microstructures of Fe-Mn-Al-C alloys. Available information on the martensite start (M_s) temperature was reviewed. By employing the M_s property model in the Thermo-Calc software together with the new thermodynamic database and experimental M_s temperatures, a set of model parameters for the Fe-Mn-Al-C system in the M_s model was optimised. Employing the newly evaluated parameters, the calculated M_s temperatures of the alloys in the Fe-Mn-Al-C system were compared with the available measured M_s temperatures. Predictions of M_s temperatures were performed for the alloys, Fe-10, 15 and 20 wt.% Mn-xAl-yC. The predictability of the M_s model can be further validated when new experimental M_s temperatures of the Fe-Mn-Al-C system are available.