Linear compartmental systems. IV. A software,under MS-Windows,for obtaining the instantaneous species concentrations in enzyme systems

Software application is implemented in this work to take full advantage of the characteristics of current operating systems and to provide the optimized symbolic kinetic equations for both enzyme and ligand species involved in enzyme reactions. This software, called SKEE-w2013, is implemented using C# language and runs under all operating systems from Windows XP up to Windows 8. It is applicable to any enzyme reaction mechanism that fits the general reaction scheme proposed previously by our group. It can be downloaded, free of charge, from http://oretano.iele-ab.uclm.es/~BioChem-mg/software.php. Besides the optimized equations, the software can provide non-optimized equations, so that the user can compare the advantage of using optimized equations rather than the non-optimized ones, whenever they do not coincide. Moreover, the software circumvents the limitations of other existing previous software tools implemented with what are nowadays obsolete programming languages and that, moreover, are limited to non-optimized kinetic equations.     

Heavy metal inputs in Northern Patagonia lakes from short sediment core analysis

Summary Heavy metal profiles of short sediment cores sampled from lakes located in Nahuel Huapi National Park, Northern Patagonia, Argentina, were determined by INAA. Core dating was performed by measuring natural ²¹⁰Pb and anthropogenic ¹³⁷Cs, and by identification of tephra layers. No evidence was found for the input increase of the trace elements Sb, Ba, Cs, Zn, Co, Hf, Ni, Se, Sr, Ti, U, and V in the lake environment. High As concentrations (up to 250 μg ^. g^-1) were found in relation with the diffusion processes of Mn and Fe oxides. Strong correlation was observed between the Br concentration and organic matter content, but no evidence was found for the relevant increase of Br inputs in recent years. Ag concentrations were found to be enriched in the upper core layers over the baseline values determined for deep layers ranging from 0.1 to 0.2 μg ^. g^-1. Hg concentration profiles were also enriched in the upper core layers over the baseline (from less than 0.07 to 0.2 μg ^. g^-1 for pre-industrial time, to 0.1 to 0.3 μg ^. g^-1 for modern times) but in relation with the increased organic matter content of the sediment.     

Determination of the fission averaged cross sections of some threshold reactions induced on chlorine, potassium, and calcium, and their role in the development of self-validated methods of neutron activation analysis

The feasibility of validating data obtained in the determination of chlorine, potassium, and calcium by neutron capture activation analysis, through their determination using threshold reactions has been studied. To this purpose the authors experimentally determined the following fission neutron spectrum averaged cross sections (in mb):³⁷Cl(n,p)³⁷S, 0.234±0.015;⁴¹K(n,α)³⁸Cl, 0.740±0.044;⁴²Ca(n,p)⁴²K, 3.09±0.22;⁴³Ca(n,p)⁴³K, 2.27±0.12;⁴⁴Ca(n,p)⁴⁴K, 0.074±0.013. The application of these values to the analysis of some reference materials are presented. Also, the problem of mutual interferences has been addressed for the following pairs:³⁶S(n,Γ)³⁷S and³⁷Cl(n,p)³⁷S;³⁷Cl(n,Γ)³⁸Cl and⁴¹K(n,α)³⁸Cl;⁴¹K(n,ψ)⁴²K and⁴²Ca(n,p)⁴²K.     

Iron oxide nanoparticles and VOx/Hexadecylamine nanotubes composite

In this work, we present the synthesis and characterization of a hybrid nanocomposite constituted by iron oxide nanoparticles and vanadium oxide/Hexadecylamine (VO_x/Hexa) nanotubes. Transmission Electron Microscopy (TEM) images show small particles (around 20 nm) in contact with the external wall of the multiwall tubes, which consist of alternate layers of VO_x and Hexa. By Energy Dispersive Spectroscopy (EDS), we detected iron ions within the tube walls and we have also established that the nanoparticles are composed of segregated iron oxide. The samples were studied by Electron Paramagnetic Resonances (EPR) and dc-magnetization as a function of the magnetic field. The analysis of the magnetization and EPR data confirms that a fraction of the V atoms are in the V⁴⁺ electronic state and that the nanoparticles exhibit a superparamagnetic behavior. The percentage of V and Fe present in the nanocomposite was determined using Instrumental Neutron Activation Analysis (INAA).     

Entrainment in condensing annular flow

Experiments were carried out on low pressure, steam-water, condensing annular flow in a 38.1 mm i.d. horizontal tube. The velocity of the steam at inlet was in the range 97–186 m/s.Measurements of the liquid film flow rate at the end of the test section, which arose as a result of condensation, entrainment, and deposition, were made by extracting the film through a porous sinter bush. The liquid flow rate in the vapour core at exit was deduced from these measurements together with a heat balance on the condenser section.These results were compared with three correlations for entrainment developed from air-water studies. On the basis of the experimental data available, there was sufficient agreement in one case to warrant further investigation.     

Experimental analysis of pp interactions between 0 and 1.2 GeV/c: Evidence for a pp → 5π effect near 1950 MeV/c2

An experimental analysis of $\text{p}\text{p}$ interactions between the $\text{p}$p threshold (√s = 1878 MeV) and √s = 2 100 MeV leads to clear evidence for an s-channel effect in the reaction $\text{p}\text{p}\text{→ π}{}^{\mathrm{+}}\text{π}{}^{\mathrm{?}}\text{π}{}^{\mathrm{+}}\text{π}{}^{\mathrm{?}}\text{π}{}^0\text{at}\text{1949 ± 10}\text{MeV}\text{/c}{}^2\text{(Γ ? 80}\text{MeV}\text{/c}{}^2\text{)}$. A comparison is made with the backward elastic scattering and charge-exchange behaviour. An interpretation in terms of an object strongly coupled to mesonic decay modes, with small or middle-sized elasticity (x ? 0.135_?0.06^+0.13) is given. No significant narrow structure is observed in the backward elastic scattering between 1.9 and 2 GeV. The experimental resolution of √s in this case is 2 MeV.