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We studied a buried interface reconstructed structure of the Ag/Si(111)3×3–Ag samples using grazing incidence X-ray diffraction with synchrotron radiation. We found that the 3interface superstructure can be explained by an inequivalent-triangle (IET) model, which has been observed on the Si(111)3×3–Ag surface at low substrate temperatures by STM. The calculated structure factors of the IET model were found to be very close to our observed ones. The reliability factor (R-factor) using the IET model was about 25%. The R-factor was improved to be much less value, 12% by considering defects of Ag atoms forming the 3structure. The Patterson map expected from the IET model having the defects was very similar to that calculated from the observed structure factors.

The in-plane structure of Si(111)21×21-(Ag+Au) surface was studied by using grazing incidence X-ray diffraction method. A total of 72 inequivalent fractional order reflections were obtained. The structural models are investigated including the previously proposed models. It is found that the Ag triangles and Si trimers are induced to displace considerably from the honeycomb chained triangle arrangement by the adsorption of Au atoms. From the analysis, the models with five Au atoms in the unit cell, which have the Au–Au interatomic distance peculiar to the 21×21periodicity, are favored.

Human chromosomes 1q21-q25, 6p21.3-22.2, 9q33-q34, and 19p13.1-p13.4 carry clusters of paralogous loci, to date best defined by the flagship 6p MHC region. They have presumably been created by two rounds of large-scale genomic duplications around the time of vertebrate emergence. Phylogenetically, the 1q21-25 region seems most closely related to the 6p21.3 MHC region, as it is only the MHC paralogous region that includes bona fide MHC class I genes, the CD1 and MR1 loci. Here, to clarify the genomic structure of this model MHC paralogous region as well as to gain insight into the evolutionary dynamics of the entire quadriplication process, a detailed analysis of a critical 1.7 megabase (Mb) region was performed. To this end, a composite, deep, YAC, BAC, and PAC contig encompassing all five CD1 genes and linking the centromeric +P5 locus to the telomeric KRTC7 locus was constructed. Within this contig a 1.1-Mb BAC and PAC core segment joining CD1D to FCER1A was fully sequenced and thoroughly analyzed. This led to the mapping of a total of 41 genes (12 expressed genes, 12 possibly expressed genes, and 17 pseudogenes), among which 31 were novel. The latter include 20 olfactory receptor (OR) genes, 9 of which are potentially expressed. Importantly, CD1, SPTA1, OR, and FCERIA belong to multigene families, which have paralogues in the other three regions. Furthermore, it is noteworthy that 12 of the 13 expressed genes in the 1q21-q22 region around the CD1 loci are immunologically relevant. In addition to CD1A-E, these include SPTA1, MNDA, IFI-16, AIM2, BL1A, FY and FCERIA. This functional convergence of structurally unrelated genes is reminiscent of the 6p MHC region, and perhaps represents the emergence of yet another antigen presentation gene cluster, in this case dedicated to lipid/glycolipid antigens rather than antigen-derived peptides.

We assessed the possible association between CagA⁺ Helicobacter pylori infection and gastric carcinogenesis in gastric cancer patients. Gastric biopsy specimens were obtained from 64 patients with gastric cancer and were histologically classified into intestinal and diffuse types. H. pylori infection was determined by cultivation, flaA-PCR and serum antibody against CagA. p53, BAX and transforming growth factor-β-RII (TGFβ-RII) gene mutations were analyzed by PCR-SSCP and direct sequencing. Intestinal and diffuse types of cancer were detected in 45 and 19 patients, respectively. H. pylori infection was found in 55 (85.9%) of 64 patients. There was no significant difference in H. pylori positivity between intestinal and diffuse types. However, the CagA antibody was positive in 15 (78.9%) of 19 patients with the diffuse type and in 22 (48.9%) of 45 patients with the intestinal type (p = 0.030). Among the 55 H. pylori-positive cases, 11 (29.7%) of the 37 patients in the CagA⁺ group were found to have p53 alterations, compared with 2 (11.1%) in the 18 CagA^- group (p = 0.182). Moreover, among the 64 gastric cancer patients, p53 alterations were more frequently found in the CagA⁺ group (29.7%) than in the H. pylori-positive CagA^- and H. pylori-negative groups (7.4%; p = 0.033). BAX gene mutations were found in 19 (29.7%) of 64 patients and there was no relationship among CagA seropositivity, cancer stages and histopathological phenotypes. In contrast, the TGFβ-RII gene mutation was only detected in one CagA^- patient. The results suggest that CagA⁺ H. pylori infection may have an important role in the development of gastric cancer patients with p53 mutations © 2001 Wiley-Liss, Inc.

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Abstract: Photodissociation of 2,2’,3,3’,5,5’,6,6’-octaphenyl-4,4’-bi-4H-pyran (D) and recombination of 2,3,5,6-tetraphenylpyranyl radical in tetrahydrofuran solution were investigated by ESR methods. The pattern of the CIDEP signal of the radical indicaess that the photodissociation occurs from the excited singlet state of D. The activatinn energy of the radical recombination was obtained to be 16 ~ 18 kJ/mol. By lowering the temperature of photorrradiatton to -140° C, a radical pair was found to be trapped in the medium and its zero field splitting parameters were determined as | D | = 0.0119 cm-1 and | E | = 0.00050 cm-1.

We have developed a high energy, high resolution monochromatic x-ray computed tomography system using synchrotron radiation. Our system is installed in a vertical wiggler beamline at the Photon Factory of the National Laboratory for High Energy Physics that can produce high brilliance x-rays in the high energy region. At the present stage, we have obtained monochromatic x-rays up to 75 keV, succeeded in taking computed tomography images of materials up to 50 keV with large absorption coefficients that could not be imaged by conventional methods, and observed three-dimensional fine structures in such materials. When the K-edge subtraction method was applied, the system could quantitatively and nondestructively measure the trace distribution of a specific element in the object of interest. In this paper we introduce the experimental system, mainly the crystal monochromator, evaluate the results, and discuss the performance of the system.

We have developed a high resolution monochromatic X-ray computed tomography system using synchrotron radiation in the energy range up to 50 keV. The system was installed in a vertical wiggler beam/ine at the Photon Factory of the National Laboratory for High Energy Physics. The system consists of a double-crystal monochromator employing asymmetric Bragg reflections, a photodiode array detector with a phosphor screen, and a microcomputer for control. cr images with a pixel size of 7.7, urn were obtained. An image subtraction technique for cr images above and below the X-ray absorption edge of iodine was also evaluated for liquid-containing glass capillaries. The results indicate that the system is very useful for nondestructively evaluating fine structures and their constituent elements.

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Optical emission intensities in the sheath region are not the same as those in the plasma region. This is because not only the electron density, but also the electron temperature, is different between the two regions. In this study a Cu rod is inserted into the plasma, and the rod potential is altered from the ground potential to a negative potential with a frequency of 20 Hz. The optical emission ray comes from the sheath region when the negative potential is applied, but comes form the plasma region at the ground potential. We can immediately detect the difference of the emission intensities between the plasma and the sheath regions by a lock-in amplifier. The pre-amplifier is placed prior to the lock-in amplifier. By using this pre-amplifier the output signal of the lock-in amplifier can be adjusted to zero for any emission line. the emission spectra from a CF4+O2 plasma are measured. A small amount of Ar gas and/or N2 gas is added and the output signal of the lock-in amplifier is adjusted to zero for either the Ar emission line or the N2 emission line. In a fluorine-contained plasma the F emission intensity normalized by the Ar one has been widely used in order to obtain the F density. This validity is confirmed by the present experiment. It is also confirmed that the CO emission intensity normalized by that of N2 is proportional to the CO density. The metastable states play an important role in the optical emission intensities of CO and N2 molecules.

The lateral spread of implanted P+ ions and the shape of the mask window have been observed simultaneously using the technique of staining the cleaved surface and scanning electron microscopy for the Si samples with the SiO2 mask window with a tapered edge. The mask edge with a gradient of 45° or 78° to the Si surface and the implanted n‐type region with a carrier concentration higher than 2×1017/cm3 are observed in the same photograph. The observed maximum lateral spread when the gradient of the mask edge is 45° is about 1.6 times larger than that when the gradient is 78°. The calculated results of the lateral spread agree relatively well with the experimental data although the precise analysis based on the definite basis is necessary.

The photoreaction of the solution system of naphthalene and 2,6-di-tert-butyl-p-cresol was investigated by a combination of optical spectroscopy, ESR and time-resolved CIDEP techniques. ESR signal of 2,6-di-tert-butyl-4-methylphenoxy radical was detected during 308 nm irradiation. Three different types of polarization mechanisms contribute to the CIDEP of the phenoxy radicals. In the initial stage RPM with singlet precursor predominates, whereas RPM with F-pairtnplet precursor persists at later stage. The contribution from TM is superimposed during all the time regions but to a small extent. Both the CIDEP intensity at the initial stage as well as the depletion rate of naphthalene during photolysis were found to be proportional to the square of the light intensity, which indicates that most phenoxy radicals were produced via a biphotonic process.

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The X-ray absorption in a 5 µm thick Ni foil for energies from 8.2 keV to 8.8 keV was measured by the photoacoustic method using a gas-microphone-cell. Results are presented for both photoacoustic amplitude and phase as a function of incident photon energy. The absorption fine structure above the NiK-edge is clearly resolved. The data are compared with a simple theory for the signal generation, and discrepancies are explained by discussing the various energy dissipation channels following the X-ray absorption.

The hydrogen-induced defects in single crystals of silicon grown by the floating-zone method in a hydrogen atmosphere, have been measured by high-energy synchrotron radiation section topography. The static Debye-Waller factor (SDWF) produced by hydrogen precipitates, which were formed in silicon under isochronal annealing, has been calculated on the basis of a statistical dynamical diffraction theory. Within a H2 molecule cluster model which we proposed for a precipitate, the size and density of hydrogen precipitates have been determined using the SDWF method and the results of infrared absorption spectrum. The character of the early stage of hydrogen precipitation indicates that hydrogen in p-type silicon is mobile and less stable, compared with that in n-type silicon.

The objective of the study was to examine the relation between the morphology of the common atrioventricular valve and regurgitation of the valve in patients with right atrial isomerism. We examined seven consecutive patients with documented right atrial isomerism who subsequently underwent postmortem examination during a 10-year period. The degree of regurgitation and the diameters of the common valve were evaluated via cineangiography, and the site of regurgitation was evaluated by echocardiography. The morphology of the common atrioventricular valve was assessed further at autopsy. Cineangiography revealed valve diameters ranging from 14.8 to 27.8 mm (mean 20.9 mm). Valvar regurgitation was revealed within 2 months of birth in all patients. Regurgitation abruptly worsened in three patients after placement of a Blalock–Taussig shunt or a central shunt and postintubation. Autopsies revealed that the common atrioventricular valve consisted of four leaflets in five patients, and three leaflets in two. The anterior leaflets were large and protruding in all patients, and the lateral leaflets were thickened in six. All patients had a mass consisting of the left lateral leaflets and chordae with direct attachment of the chordae to the ventricular muscle (the right lateral leaflet was attached to the ventricular muscle and immobile in one patient). The lateral leaflets clung to the ventricular wall and exhibited poor movement in six patients. Leaflets with poor mobility corresponded to the regurgitant valvar site as assessed by echocardiography in six patients; and the regurgitation in three patients with acute deterioration occurred at the valvar side with poor mobility. It is concluded that the common atrioventricular valve in patients with right atrial isomerism has morphologic characteristics that may be associated with valvar regurgitation and malignant potential for abrupt deterioration after replacement of systemic–pulmonary shunting.

The X-ray absorption in a 5 μm thick Ni foil for energies from 8.2 keV to 8.8 keV was measured by the photoacoustic method using a gas-microphone-cell. Results are presented for both photoacoustic amplitude and phase as a function of incident photon energy. The absorption fine structure above the Ni K-edge is clearly resolved. The data are compared with a simple theory for the signal generation, and discrepancies are explained by discussing the various energy dissipation channels following the X-ray absorption. [ABSTRACT FROM AUTHOR]

1. The internal resistance of the cell battery of frog ventricular muscle fiber was measured with an intracellular microelectrode. Its mean value was 5.67±0.91 MO.

The design and performance of a new water‐cooled and doubly bent crystal monochromator for Compton scattering experiments are described. Its mechanical system is similar to that of a usual bent cylindrical X‐ray mirror. A monolithic Si (111) crystal is mounted on a water‐cooled and cylindrically polished copper crystal holder with liquid Ga–In alloy between them in order to obtain good thermal and mechanical contact. The sagittal bending radius of the holder, Rs, is 508 mm. The holder is mounted on a mechanical bender making a meridian radius, Rm, of 596 m. The performance of the monochromator, which has been installed at the Photon Factory Accumulator Ring beamline NE1, is as follows. The focused beam size, flux and energy resolution for 60 keV X‐rays are 0.5 mm in height and 2.0 mm in width, 5 × 1012photons s−1and about 60 eV, respectively. The new monochromator gives one order higher brightness at the sample position and also better energy resolution than the previous monochromator. The overall momentum resolution for high‐resolution Compton scattering experiments becomes 0.08 atomic units, and the background can be reduced by a third, because it is possible to insert a fine slit after the analyser crystal without losing any Compton scattering signal.

High‐pressure apparatus for Compton scattering experiments has been developed to study the momentum distribution of conduction electrons in metals and alloys at high pressure. This apparatus was applied to observe the Compton profile of metallic Li under pressure. It was found that the Compton profile at high pressure could be obtained within several hours by using this apparatus and synchrotron radiation. The result on the pressure dependence of the Fermi momentum of Li obtained here is in good agreement with that predicted from the free‐electron model.

Tungsten-silicide-gate self aligned GaAs MESFETs were fabricated on a very thin channel layer formed by implantation through an AlN layer on a semi-insulating GaAs substrate. Transconductance of the through-implanted MESFETs showed a 30 to 50% increase as compared with that of conventional self aligned MESFETs, and reached its maximum value at 300 mS/mm for 1μm-gate-length FETs.

We present the first experimental observation of spin reorientation phase transitions (SRT) with the X-Ray circular magnetic dichroism (XCMD) technique. Both the first-order SRT in Er2Fe14B and the second-order one in Nd2Fe14B have been clearly detected, demonstrating the feasibility of this technique for studying SRTs.