Towards the identification of autologous blood transfusions through capillary electrophoresis

The use of autologous blood transfusions by endurance athletes has remained one of the most difficult doping practices to detect. The implementation of the Athlete’s Biological Passport by some sporting bodies has proved to be effective; however, the analysis relies on the long-term monitoring of numerous biological markers, looking for abnormal variations in a number of biological markers to indicate doping. This work introduces an approach to identify autologous blood transfusions by examining the red blood cells (RBCs) directly. By using high-speed capillary electrophoretic separations, the relative distribution of the sizes of the RBCs in a sample can be established in under 3 min, following the preparation of the cells. As RBCs that have been stored for transfusions undergo vesiculation, the relative size of the transfused cells differs from the native cells. The capillary electrophoretic separation allows for a rapid examination of this distribution and the changes that are seen when transfused RBCs are mixed with native cells. In this work, the effectiveness of this approach is demonstrated in the identification of simulated (in vitro) autologous blood transfusions performed with blood samples from three highly trained cyclists; it was possible to rapidly identify when as little as 5 % of the RBCs in the sample were from a simulated autologous transfusion.

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Mikrochemie

Ohne Zusammenfassung     

A redox series of gallium(III) complexes: ligand-based two-electron oxidation affords a gallium-thiolate complex

We have prepared a series of gallium(III) complexes of the redox active iminopyridine ligand (IP). Reaction of GaCl(3) with iminopyridine ligand (IP) in the presence of either two or four equivalents of sodium metal resulted in the formation of deep green (IP(-))(2)GaCl (1), or deep purple [(DME)(3)Na][(IP(2-))(2)Ga] (2a), respectively. Complex 1 is paramagnetic with a room temperature magnetic moment of 2.3 μ(B) which falls to 0.5 μ(B) at 5 K. These observations indicate that two ligand radicals comprise a triplet at room temperature which becomes a singlet due to antiferromagnetic coupling at low temperature. Complex 2 is diamagnetic. Cyclic voltammograms recorded on 0.3 M Bu(4)NPF(6) THF solutions of [Na(THF)(6)][(IP(2-))(2)Ga](-) (2b) indicate that oxidation of 2b occurs in two two-electron steps at -1.31 V and -0.54 V vs. SCE. The observation of two-electron redox events indicates that electronic coupling through the gallium(III) center is minimal and that the two IP ligand on 2b are oxidized concurrently. Oxidation of 2 with one equivalent of MeS-SMe afforded the two-electron oxidized product (IP(-))(2)Ga(SMe) (3). This complex has an electronic structure analogous to 1. Accordingly, both 1 and 3 are deep green in color and magnetic susceptibility measurements performed on 3 confirm the triplet character of the complex at room temperature. Electron paramagnetic resonance experiments on 1 and 3 display a quartet signal at g = 2.0 which confirmed the triplet nature of the compounds, and a half field signal consistent with the integer spin state.     

Logarithmic Pooling of Priors Linked by a Deterministic Simulation Model

Abstract

We consider Bayesian inference when priors and likelihoods are both available for inputs and outputs of a deterministic simulation model. This problem is fundamentally related to the issue of aggregating (i.e., pooling) expert opinion. We survey alternative strategies for aggregation, then describe computational approaches for implementing pooled inference for simulation models. Our approach (1) numerically transforms all priors to the same space; (2) uses log pooling to combine priors; and (3) then draws standard Bayesian inference. We use importance sampling methods, including an iterative, adaptive approach that is more flexible and has less bias in some instances than a simpler alternative. Our exploratory examples are the first steps toward extension of the approach for highly complex and even noninvertible models.     

On the modified Leverrier-Faddeev algorithm

Properties of an eigenmatrix proposed by Faddeev and an extension thereof investigated by Gower are deduced from consideration of the adjoint and reduced adjoint of the characteristic matrix sI — A.     

Thermal expansion op NbSe2 and TaS2

The lattice parameters a₀ and c₀ of the hexagonal 2H polytype of NbSe₂; have been measured over the temperature range 156–478 K for a₀, and 138–482 K for c₀. The lattice parameter c₀ of the hexagonal 2H polytype of TaS₂ has been measured between 151 and 472 K. The lattice parameters a₀ and c₀ for the octahedral 1T polytype of TaS₂ been measured between 165 and 488 K. Over these temperature ranges, the following average coefficients of thermal expansion have been measured; 2H-NbSe₂, 6.6 × 10^?6K^?1 along the a-axis, 19.9 × 10^?6 K^?1 along the c-axis; 2H-TaS₂, 15.6 × 10^?6 K^?1 along the c-axis; IT-TaS₂, 12.7 × 10^?6 K^?1 along the c-axis. The parameter c₀ of 1T-TaS₂ undergoes two transitions which may be explained in terms of charge density waves.     

Photochemistry of 3,6-dihydro-1,2-oxazines: A versatile route to substituted pyrroles

A high yield pyrrole synthesis which employs a sequence of cyclo-addition, photoextrusion of H₂O and Birch reduction has been developed.     

2.3. Methodology of OR

We present and analyze a generalization of the standard decision analysis model of sequential decisionmaking under risk. The decision tree is assumed given and all probabilities are assumed to be known precisely. Utility values are assumed to be affine in an imprecisely known parameter. The affine form is sufficiently general to allow importance weights or the utility values themselves to be represented by the imprecise parameter. Parameter imprecision is described by set inclusion. A relation on all available alternatives is assumed given for each decision node. The intent of each (not necessarily complete) relation is to model the decisionmaker's directly expressed preferences among the available alternatives at the associated decision node. A numerical procedure is developed to determine the set of all strategies that may be optimal and the corresponding set of all possible parameter values. An example illustrates the procedure.     

High-performance liquid chromatography/chemiluminescence determination of biological thiols with N-[4-(6-dimethylamino-2-benzofuranyl)phenyl]maleimide

The peroxyoxalate chemiluminescence detection of biological thiols combined with high-performance liquid chromatography (HPLC) is described. SH groups of the thiol compounds including glutathione (GSH), cysteine, N-acetylcysteine, cysteamine, and D-penicillamine were labelled with N-[4-(6-dimethylamino-2-benzofuranyl)phenyl]maleimide (DBPM), a specific fluorogenic reagent for SH group. The labelling reaction was carried out at 60 degrees C for 30 min and at pH 8.5 and a sample of the resulting reaction mixture was subjected to HPLC. Five kinds of labelled thiols were separated within 12 min on ODS-80 column (150 x 4.6 mm ID; 5 microns) and detected in the ranges from 500 fmol to 2 pmol/100 microL (cysteamine and N-acetylcysteine), to 3 pmol/100 microL (cysteine) and to 5 pmol/100 microL (GSH and D-penicillamine). The lower detection limits were from 7 fmol (cysteamine) to 113 fmol (GSH) per 100 microL (S/N = 2). The method was applied to the determination of thiols in a rat liver. The amounts of glutathione and cysteine were 1.23 +/- 0.15 mumol/g (n = 5) and 0.15 +/- 0.04 mumol/g (n = 5), respectively.