Therapeutic drug monitoring of cefepime with micellar electrokinetic capillary chromatography: Assay improvement,quality assurance,and impact on patient drug levels

The improvement and performance of a micellar electrokinetic capillary chromatography assay for cefepime in human serum and plasma with a 50 μm id fused‐silica capillary elongated from 40 to 60 cm is reported. Sample preparation with dodecylsulfate protein precipitation at pH 4.5, the pH 9.1 separation medium, and the applied voltage were as reported previously [16]. The change resulted in a significant lower current, higher resolution, and increased detection time intervals. The performance of the assay with multilevel internal calibration was assessed with calibration and control samples. Quality assurance data of a 2‐year period assessed under the new conditions demonstrated the robustness of the assay. In serum samples of patients who received both cefepime and sulfamethoxazole, cefepime could not be detected due to the inseparability of the two compounds. The presence of an interference can be recognized by an increased peak width (width > 0.2 min), the appearance of a shoulder or an unresolved double peak. The patient data gathered during a 3‐year period reveal that introduction of therapeutic drug monitoring led to a 50% reduction of the median drug level. The data suggest that therapeutic drug monitoring can help to minimize the risk of major adverse reactions and to increase drug safety on an individual basis.     

Comment on “Understanding the scalar meson q\bar{q} nonet”

It is shown that the incomplete scalar meson nonets found by T?rnqvist [1] and T?rnqvist & Roos [2], employing a new version of the Helsinki unitarised quark model, should in fact be complete, including an as yet unconfirmed light below 1 GeV (old ) and the established (1500). A detailed comparison is presented with the predictions of the Nijmegen unitarised meson model, in which two complete scalar nonets show up below 1.5 GeV [3]. The reason for the flavour-nonet breaking found in [1,2] we argue to originate in the use of coupling constants for the three-meson vertex which are not independent of flavour. Also some statements made in [1] are critically reviewed. Received: 17 February 1999 / Published online: 15 July 1999     

Micro-solid oxide fuel cells: status,challenges, and chances

Abstract  Micro-solid oxide fuel cells (micro-SOFC) are predicted to be of high energy density and are potential power sources for portable electronic devices. A micro-SOFC system consists of a fuel cell comprising a positive electrode-electrolyte-negative electrode (i.e. PEN) element, a gas-processing unit, and a thermal system where processing is based on micro-electro-mechanical-systems fabrication techniques. A possible system approach is presented. The critical properties of the thin film materials used in the PEN membrane are discussed, and the unsolved subtasks related to micro-SOFC membrane development are pointed out. Such a micro-SOFC system approach seems feasible and offers a promising alternative to state-of-the-art batteries in portable electronics. Graphical abstract  Graphical Abstract text      

ADP晶体的全方位生长方法研究

采用一种全新的ADP晶体生长方法,使晶体首先恢复其理想外形,实现晶体的全方位生长,从而提高晶体的生长速度.并对所得晶体进行了透过率,激光散射,摇摆曲线测试及热重差热分析,与常规生长方法比较并分析了全方位生长方法的优势.     

Dual-channel phase-shifting interferometry for microscopy with second wavelength assistance

Dual-channel phase-shifting interferometry for simultaneous phase microscopy is presented. Red and blue light beams are used for microscope illumination. A 45 tilted beamsplitter replicates the object and reference waves in red light together with the object wave in blue light into two parallel beams. The two resulting quadrature phase-shifting interferograms in red light and the object waves in blue light are generated in the two channels. The two interferograms are recorded simultaneously by a color charge-coupled device (CCD) camera, and can be separated via RGB components of the recorded color patterns without crosstalk. As a result, the phase of tested specimen can be retrieved. The feasibility of the proposed method is demonstrated by test performed on a microscopic specimen.     

Absorption changes under UV illumination in doped PMMA

The absorption spectra of poly(methyl methacrylate) (PMMA) doped with the photoinitiator 2,2-dimethoxy-2-phenylacetophenone (DMPA) change under illumination with UV light. Time-resolved measurements of the kinetics of the absorption changes at 352 nm prove the existence of a second light-induced reaction besides the expected light-induced decay of the photoinitiator. We propose a model for this second process which is in good agreement with the observed experimental facts. Received: 17 July 2000 / Published online: 5 October 2000     

Positive and Negative Mixtures in Relativistic Schrödinger Theory

The general formalism of relativistic Schrödinger theory (RST) is specialized to a scalar two-particle system with electromagnetic interactions (scalar helium atom). The set of dynamically allowed field configurations splits up into positive and negative mixtures and pure states. The static and spherically symmetric solutions are constructed by means of first-order perturbation theory for the case of an attractive Coulomb potential. The corresponding energy levels for the positive and negative mixtures resemble the emergence of ortho and para states in the conventional quantum theory. The associated energy eigenvalues predicted by the RST seem to undergo a certain kind of mixture degeneracy as the RST analog of the conventional exchange degeneracy. The charge densities of the positive mixtures assimilate, whereas the densities of the negative mixtures recede from one another. Thus, positive (negative) mixtures strongly resemble the bosonic (fermionic) matter of the conventional theory when the Pauli principle is applied.     

Interfacial Interactions and Properties of Polyethylene‐Layered Silicate Nanocomposites

Summary: Organically modified montmorillonites (OMs), carrying alkyl chains, phenyl groups, or a combination of both, were prepared and compounded with polyethylene. The oxygen permeability coefficients and tensile properties of the nanocomposites were correlated to the exfoliation of the OMs. Partial exfoliation was achieved, although no intercalation was observed. Aromatic moieties attached to the clay surface led to a stronger interaction between the OM layers and less exfoliation.

Transmission electron micrograph of a 2.8 vol.‐% dioctadecyldimethylammonium nanocomposite. The dark lines are cross sections of aluminosilicate layers.     

Commercial SiC device processing: Status and requirements with respect to SiC based power devices

SiC power devices have been commercially available since 2001. In the meantime the standard wafer diameter increased from 2″ to 3″ and a lot of processes which are needed for SiC device technology and which have not been standard in Si device fabrication (e.g. rapid thermal annealing of metal layers, stepper lithography for 3″ etc.) have now found a place in the list of common processes. On the other hand there are still processing issues or process steps that are not yet solved satisfactorily or not yet fulfilling the standards set in the production of Si devices. After a short introduction about the application and market of SiC power devices the paper will present a brief status of today’s productive SiC device processing. This part will mainly focus on Schottky diode manufacturing which is currently the only SiC power device produced in significant amounts. In a second part the paper will focus on remaining issues like wafering, availability of defect density monitoring, ohmic contact formation, high quality substrates and epi, oxidation, and post implantation annealing. All topics will be related to the needs resulting from an industrial point of view concerning process stability, influence on device costs, quality and on commercialization. The paper concludes that the major tasks to be attacked are the quality and price of substrates and epitaxial layers. Other technical issues are ranked behind those.