Synchrotron-radiation X-ray topography of surface strain in large-diameter silicon wafers.

Using a 300 mm-wide monochromatic X-ray beam obtained at beamline BL20B2 of SPring-8, the difference in surface-strain distribution caused by various steps of silicon-wafer manufacturing, i.e. slicing, lapping, etching, grinding and polishing, was studied. The asymmetric 511 reflection of 21.45 keV X-rays, incident at a glancing angle of 0.26 degrees, was used to obtain topographs over the whole surface of a 200 mm-diameter (100) CZ silicon wafer. Differences in crystallinity and in warp between the surfaces at different steps of the manufacturing process (firstly after the lapping following the slicing, and then after successive etching, grinding and polishing) were clearly observed. The former gave a topographic image over the whole area with a one-shot exposure because of their wide rocking curves (50-70 arcsec FWHM), which indicate poor crystallinity. The latter, on the other hand, showed sharper curves (4-5 arcsec FWHM), which indicate good crystallinity in local areas, and the existence of warp, and therefore required step scanning of omega-rotation to cover the whole surface in topography measurements. The effect of each step in the process is also discussed.

Multienzyme control serum (Seraclear-HE) containing human enzymes from established cell lines and other sources. 3: Evaluation as candidate working enzyme reference material for gamma-glutamyltransferase.

Seraclear-HE, containing gamma-glutamyltransferase (GGT, EC 2.3.2.2) derived from the cell culture of a human macrophage cell line, was evaluated as a candidate enzyme reference material (ERM) to calibrate routine methods in terms of a Reference Method for GGT. We have compared this preparation with commercially available materials, including Certified Reference Material 319, at 30 degrees C and 37 degrees C with respect to kinetic properties and with respect to commutability between the Reference Method and each of 15 analytical procedures involving five structurally different donor substrates. GGTs of human origin are far more commutable with reagents of varied types than are GGTs derived from animals. Calibration of 44 patients' sera with Seraclear-HE decreased average intermethod variation from 20% to approximately 4%, whereas GGTs of animal origin showed intermethod variations of approximately 30% with no benefit from calibration. Seraclear-HE is promising as a secondary or working ERM to be used as an intermethod calibrator.

Multienzyme control serum (Seraclear-HE) containing human enzymes from established cell lines and other sources. 2: Evaluation as candidate working enzyme Reference Material for alanine and aspartate aminotransferases.

Seraclear-HE, containing seven enzyme analytes from human sources, was evaluated as an intermethod calibrator for aspartate aminotransferase (AST) and alanine aminotransferase (ALT) to transfer Reference Method values to seven routine methods, including one based on hydrogen peroxide detection for possible unification of values (interlaboratory comparability of data). The commutabilities of AST from erythrocytes and ALT from a hepatoma cell line were studied between the consensus methods of Japan Society of Clinical Chemistry (chosen as the Reference Methods) and each of the automated routine methods at reaction temperatures of 30 degrees C and 37 degrees C. For AST, calibration of patients' sera with Seraclear-HE decreased average intermethod variation (CV) from 12% to 2%; for ALT, the decrease was from 20% to 3%. For both enzymes, Seraclear-HE was judged to be commutable between the Reference Methods and each of the methods investigated. The limitations for such use are discussed.

Multienzyme control serum (Seraclear-HE) containing human enzymes from established cell lines and other sources. 1: Preparation and properties.

We have developed a new multienzyme control serum, Seraclear-HE, which was designed to function not only as an accuracy and precision control serum but also as an intermethod calibrator for unifying interlaboratory clinical enzyme data in terms of reference method values. Seraclear-HE contains as analytes the following enzymes of human origin only: aspartate aminotransferase (AST, EC 2.6.1.1) and lactate dehydrogenase (LD, EC 1.1.1.27) from erythrocytes; alanine aminotransferase (ALT, EC 2.6.1.2) from a hepatoma cell line; alkaline phosphatase (ALP, EC 3.1.3.1) from an amnion cell line; creatine kinase (CK, EC 2.7.3.2) from an embryo kidney cell line; gamma-glutamyltransferase (GGT, EC 2.3.2.2) from a macrophage cell line; and amylase (AMY, EC 3.2.1.1) from urine and saliva. The seven partly purified enzymes were lyophilized in partially delipidated human serum containing sucrose (50 g/L), pyridoxal 5'-phosphate (30 mmol/L), and other stabilizers. The material is stable for at least 2 years at temperatures < or = 10 degrees C. For two concentrations of this preparation, reference method values (mainly International Federation of Clinical Chemistry and Japan Society of Clinical Chemistry) obtained at both 30 degrees C and 37 degrees C are assigned.

[Measurement of enzyme activity of control materials containing human enzymes by IFCC reference methods].

In order to unify interlaboratory clinical enzyme data, a reference method and reference material are necessary for each enzyme. Although reference methods recommended by various societies of clinical chemistry including JSCC are now available for some routinely measured clinical enzymes, the availability of secondary enzyme references or calibrators, limits the practical application of standardization concept for minimizing present interlaboratory variation of enzyme data. Since control sera prepared by adding enzymes from human cell cultures to a pool of human serum may meet the requirements as candidates for such reference materials, we attempted to assign values to 6 enzymes present in the materials by mainly the IFCC reference methods following the procedures as strictly as possible and yet with modifications where necessary. This paper describes each step of the value assignment for accuracy control purposes.