A review of the relationship between quality control and donor sample results obtained from serological assays used for screening blood donations for anti-HIV and hepatitis B surface antigen

Quality control principles, initially designed for manufacturing, have been applied to clinical chemistry and later to serological testing for infectious diseases. Methods for setting control limits have been included using the effects of assay performance on clinical outcomes. However, this approach assumes that the reactivity of patient samples change proportionally with the results of quality control samples tested in the same assay. Although this may be the case for clinical chemistry, this assumption has never been tested for serological assays. During a 9-month period, 177910 and 185684 donor test results for HBsAg and anti-HIV, respectively, were analysed and compared with 712 HBsAg and 710 anti-HIV results obtained from a single batch of a multimarker quality control sample obtained from the same assays. Results of the analysis showed that the negative donor results did not change in proportion with the changes experienced by the quality control sample results as determined by regression coefficients, particularly when results obtained from different reagent batches were compared. There were insufficient results obtained from positive samples for a similar analysis. However, investigations show that, even if the reactivity of positive donor samples changed in proportion with the change in reactivity of the quality control sample, few false-negative donor test results would have occurred.     

Improved method for determining binary adsorption isotherms by using concentration pulse chromatography: adsorption of CO2 and N2 by silicalite at different pressures

Adsorption separation of carbon dioxide from nitrogen at different system total pressures with silicalite as the adsorbent was studied by using concentration pulse chromatography. Improving the methodology for determining binary adsorption isotherms by concentration pulse method (CPM) was also the goal of this study. Binary adsorption isotherms, x–y phase diagrams and separation factor plots have been determined at 26 °C to look at the influence of pressure on the separation using concentration pulse chromatography. Available methods for determining binary adsorption isotherms using CPM have been reviewed and shown to be incapable of interpreting this particular binary system. An improved novel model has been proposed to interpret the data in this study. It has been referred to as the Kennedy-Tezel concentration pulse method (KT-CPM) and has been shown to be superior to other methods used in the literature. Results using this data were found to be consistent with the previous results in the literature. The binary isotherms for the CO₂–N₂ system show a decrease in CO₂ selectivity as total system pressure increases. The optimal separation factor for silicalite was found to increase with decreasing system pressure and decreasing mole fraction of CO₂ in the feed mixture.     

A Cobalt Pyrenylnitronylnitroxide Single‐Chain Magnet with High Coercivity and Record Blocking Temperature

Coordination of a [Co(hfac)₂] moiety (hfac=hexafluoroacetylacetonate) with a nitronylnitroxide radical linked to bulky, rigid pyrene (PyrNN) gives a helical 1:1 chain complex, in which both oxygen atoms of the radical NO^. groups are bonded to Co^II ions with strong antiferromagnetic exchange. The complex shows single‐chain magnet (SCM) behavior with frequency‐dependent magnetic susceptibility, field‐cooled and zero‐field‐cooled susceptibility divergence with a high blocking temperature of around 14 K (a record among SCMs), and hysteresis with a very large coercivity of 32 kOe at 8 K. The magnetic behavior is partly related to good chain isolation induced by the large pyrene units. Two magnetic relaxation processes have been observed, a slower one attributable to longer, and a faster one attributable to short chains. No evidence of magnetic ordering has been found.     

ICP-AES扩展通道法测定稀土镁合金中稀土总量、镁、钙、锰、铁

本文介绍了用ICP－AES测定稀土镁合金中稀土总量、钙、镁、锰、铁的方法，其中，稀土总量以铈的量进行换算，而铈 的测量通道通过扩展手段来设置。文中对样品的处理、测定的条件进行了较详细的研究，并对测量的精密度、准确度进行了考查。实验证明，该方法简便、结构可靠。     

New Pt(0) Nanoparticles as Highly Active and Reusable Catalysts in the C1–C3 Alcohol Oxidation and the Room Temperature Dehydrocoupling of Dimethylamine-Borane (DMAB)

New Pt(0) nanoparticles were easily and reproducibly prepared by the simultaneous reduction method using 1-butylamine (BA) and tributylamine (TBA) for the first time as capturing ligands at room temperature. X-ray diffraction, X-ray photoelectron microscopy and transmission electron microscopy measurements verify the formation of well-dispersed Pt(0) nanoparticles [~3.63 and ~3.98 nm for catalysts prepared using BA (catalyst I) and TBA (catalyst II), respectively] on an activated carbon surface. The catalytic performances of these nanoparticles in terms of activity, isolability and reusability were investigated for both alcohol oxidation and the dehydrocoupling of dimethylamine-borane (DMAB). These nanoparticles were shown to be as active and reusable heterogeneous catalysts even at room temperature. The prepared catalysts can catalyze the dehydrogenation of DMAB with one of the highest known activities at room temperature and also C1–C3 alcohol oxidation with very high electrochemical activities.     

Grating coupler integrated photodiodes for plasmon resonance based sensing

In this work, we demonstrate an integrated sensor combining a grating-coupled plasmon resonance surface with a planar photodiode. Plasmon enhanced transmission is employed as a sensitive refractive index (RI) sensing mechanism. Enhanced transmission of light is monitored via the integrated photodiode by tuning the angle of incidence of a collimated beam near the sharp plasmon resonance condition. Slight changes of the effective refractive index (RI) shift the resonance angle, resulting in a change in the photocurrent. Owing to the planar sensing mechanism, the design permits a high areal density of sensing spots. In the design, absence of holes that facilitate resonant transmission of light, allows an easy-to-implement fabrication procedure and relative insensitivity to fabrication errors. Theoretical and experimental results agree well. An equivalent long-term RI noise of 6.3 × 10(-6) RIU/√Hz is obtained by using an 8 mW He-Ne laser, compared to a shot-noise limited theoretical sensitivity of 5.61 × 10(-9) RIU/√Hz. The device features full benefits of grating-coupled plasmon resonance, such as enhancement of sensitivity for non-zero azimuthal angle of incidence. Further sensitivity enhancement using balanced detection and optimal plasmon coupling conditions are discussed.     

Optimal design of phase function in Generalized DFT

Recently, a theoretical framework for Generalized DFT (GDFT) with nonlinear phase functions exploiting the phase space to design various constant modulus orthogonal transforms was introduced. This paper extends prior work to design longer bases widely used in real world communications systems. GDFT provides flexibilities in phase space yielding performance improvements over other code families including DFT in correlation metrics. GDFT phase functions are optimally designed in order to reduce inter carrier interference (ICI) and inter-symbol interference (ISI) that dictate the performance of a multiuser channel. It is presented in the paper that superior correlation of GDFT over DFT manifests itself in improved BER performance in direct sequence CDMA based multi-user communications systems     

The solution of high-order nonlinear ordinary differential equations by Chebyshev Series

By the use of the Chebyshev series, a direct computational method for solving the higher order nonlinear differential equations has been developed in this paper. This method transforms the nonlinear differential equation into the matrix equation, which corresponds to a system of nonlinear algebraic equations with unknown Chebyshev coefficients, via Chebyshev collocation points. The solution of this system yields the Chebyshev coefficients of the solution function. An algorithm for this nonlinear system is also proposed in this paper. The method is valid for both initial-value and boundary-value problems. Several examples are presented to illustrate the accuracy and effectiveness of the method.     

Synthesis and Characterization of Polyvinylferrocene/Polypyrrole Composites

Conducting polymer composites of polyvinylferrocene and polypyrrole (PVF/PPy) were synthesized chemically by the in situ polymerization of pyrrole in the presence of PVF using FeCl₃ as oxidant. Acetic (CH₃COOH) and boric (H₃BO₃) acids were used as the synthesis medium. Effects of the synthesis medium on the properties of the PVF/PPy composite were investigated. The PVF/PPy composites and homopolymers were characterized by fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and magnetic susceptibility techniques. Conductivity measurements were performed using the four‐probe technique. We found that the conductivities of PVF/PPy‐H₃BO₃ (1.19 S cm^?1) and PVF/PPy‐CH₃COOH (4.5×10^?1 S cm^?1) increased relative to those of the homopolymers of PPy‐H₃BO₃ (2.1×10^?2 S cm^?1) and PPy‐CH₃COOH (1.2×10^?2 S cm^?1) due to the interaction of PVF with the pyrrole moiety. The stability of all homopolymers and composites were investigated by thermogravimetric analysis and by conductivity measurements during heating‐cooling cycles. There was a small drop in conductivity caused by the annealing of PVF/PPy composites at 70°C. The conductivity of all samples increased with temperature and exhibited stable electrical behavior with increasing temperature. TGA analysis of samples showed that the composites were more stable than the homopolymers or PVF separately. The magnetic susceptibility values of samples were negative, except for PVF/PPy‐H₃BO₃. Morphology changes of the composites investigated by scanning electron microscopy (SEM), attributed to synthesis conditions, have a significant effect on their conductivity.     

关于可列非齐次马氏链Cesaro平均收敛性及二元函数的强大数定律

该文的目的是要研究可列非齐次马氏链的Cesaro平均收敛性及二元函数的强大数定律.并利用这两者研究可列非齐次马氏链的Shannon-Mcmillan定理.