Reflectance spectra of extreme ultraviolet mirrors for synchrotron radiation

Reflectance spectra have been measured for many materials in the wavelength range from 90 Å to 400 Å. The angle of incidence ranged from 20° to 85°. The samples were chemical-vapor-deposited silicon carbide (CVD-SiC), a single crystal of silicon with (100) surface, fused quartz, zerodur, pyrex, gold, platinum, copper and two kinds of steel. To obtain reflectances for surfaces for practical use, measurements were made on surfaces sufficiently exposed to air. Reflectances for s-polarized light (R_s) were measured for all samples. On CVD-SiC, gold and platinum, reflectances for p-polarized light (R_P) were also observed. At short wavelengths and large angles of incidence, the difference between R_s and R_P is small, and R_P happened to exceed R_s in contrast to the result from the Fresnel equation. This may be due to the deviation of the present surfaces of mirrors from an ideal plane. Reflectance spectra of surfaces prepared by some feasible techniques are also presented.     

Metallic Oxide Catalyzed Growth of Carbon Nanotubes

Carbon nanotubes were created in the cathode deposit by DC arc-discharge evaporation of the graphite rods containing Y₂O₃, La₂O₃ or SC₂O₃ These metallic oxides have the catalytic action to promote the growth o nanotubes. The most remarkable catalytic effect was observed for the case of metallic oxide annexation of 2∼8wt % and arc current of 165∼196A.     

Enhanced ketogenesis in the kidney during hepatic inflow occlusion with the administration of Ringer's acetate solution

BACKGROUND: The blood levels of ketone bodies, which are synthesized principally in the liver, were maintained even during hepatic inflow occlusion if Ringer's acetate solution (AR) was administered, resulting in an improvement of hepatic energy level in the reperfusion phase, as reported in our previous experimental study. The current study was designed to prove that the kidneys are the organs that contribute to synthesize ketone bodies during hepatic inflow occlusion if AR is administered. METHODS: The arterial, central venous, renal venous, and renal tissue ketone body concentrations were determined in rabbits administered AR or Ringer's lactate solution (LR) at 20 minutes of hepatic ischemia and at 30 minutes of reperfusion. The concentrations were also compared in rabbits under AR infusion with or without hepatic ischemia for 20 minutes. Statistical analyses were performed by means of ANOVA: RESULTS: With AR the renal venous ketone body concentration not only was higher than that with LR (p < 0.001) but also was higher than the arterial concentration (p = 0.05). The renal tissue ketone body concentration was higher than in those with LR (p < 0.001) and also than in those without occlusion (p < 0.001). CONCLUSIONS: Ketogenesis is enhanced in the kidney and may compensate for hepatic loss of ketogenic function during hepatic inflow occlusion under AR administration.     

Interbronchoscopist variability in the diagnosis of lung cancer by flexible bronchoscopy

STUDY OBJECTIVE: We evaluated the interbronchoscopist variability in the diagnosis of lung cancer by flexible bronchoscopy. DESIGN AND SETTING: A retrospective review of the bronchoscopic records and clinical charts of patients at a university-affiliated hospital. PATIENTS AND MEASUREMENTS: All records of flexible bronchoscopic procedures performed for the diagnosis of lung cancer were retrospectively reviewed, and procedures that obtained histologic or cytologic evidence of malignancy were considered positive. Rates of positivity were compared according to the following factors: operator, operator experience, bronchoscopic findings, tumor location, and tumor laterality. Factors that affected the positivity rate were evaluated using logistic regression analysis. RESULTS: Of 384 bronchoscopic procedures performed in 353 patients, 275 (72 percent) were positive. The positivity rate differed significantly depending on the operator (p = 0.003) and the bronchoscopic findings (p < 0.001). A difference between operators was noted in technically difficult cases without epithelial or subepithelial findings and when tumors were located in the upper lobe or the superior segment of the lower lobe. The bronchoscopic findings and the operator also emerged as factors significantly affecting the positivity rate in the logistic analysis. CONCLUSIONS: The diagnostic yield of bronchoscopy for lung cancer is dependent on both the type of bronchial lesion present and the bronchoscopist.     

Combination of arachidonic acid and guanosine 5'-O-(3-thiotriphosphate) induce translocation of rac p21s to membrane and activation of NADPH oxidase in a cell-free system

The superoxide-generating NADPH oxidase system in phagocytes consists of membrane-associated cytochrome b558 and three cytosolic components named p67-phox, p47-phox, and rac p21s. In a cell-free system consisting of membrane and cytosol, the oxidase can be activated with guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) and an unsaturated fatty acid such as arachidonic acid (AA). Incubation of cytosol and membrane with AA alone caused clear translocation of p47-phox and p67-phox to the membrane, but only slight translocation of rac p21s. GTP gamma S alone did not significantly induce the translocation of rac p21s. However, GTP gamma S in combination with AA markedly augmented rac p21s translocation to the membrane. The translocation of rac p21s is not induced by GDP or GDP beta S. These results indicate that the GTP-bound active form of rac p21s is the entity that is translocated to the membrane by the action of AA.     

Notes on the dynamic behavior of hysteretic devices

A large class of sensors has nonlinear input-output characteristics; the task of addressing their dynamic behavior is very interesting. These sensors include magnetic field sensors (fluxgate sensors), SQUID devices, ferroelectric sensors, and mechanical sensors made of piezoelectric materials. Over the past few years there has been increasing interest in the sensing properties of ferroelectric devices based on piezoelectric, dielectric, and conduction phenomena. The principal types of sensors are infrared sensors, pressure sensors, force and motion sensors, flow sensors, hydrophones, ultrasonic transducers for medical imaging, and material testing and temperature sensors. Several application fields are automotive, aerospace, communications, and environmental monitoring. Nonvolatile random access memories are another field of application. A conceptual understanding of switching dynamics for these devices is of scientific and technological interest and requires experiments to observe their static and dynamic behavior and to develop suitable models. In the field of measurement devices, for example, the design of sensors and actuators requires the use of efficient models. This emphasizes the need for both models and user friendly experimental setup allowing for the characterization of such classes of devices. Following sections describe the behavior of a ferroelectric device and an innovative analytical model aimed to predict its dynamics.     

Crack opening behavior of penetrated crack under cyclic or monotonic loading

Crack opening displacements (CODs) were examined experimentally at room temperature for both plate and pipe specimens containing a surface crack. Application of COD solutions from plate specimens, as proposed by the present authors, to pipe specimens were investigated. COD after penetration could be satisfactorily determined regardless of a type of load using the COD, solutions proposed by the authors.     

EFFECTS OF CRACK LENGTH, NOTCH ROOT RADIUS AND GRAIN SIZE ON FRACTURE TOUGHNESS OF FINE CERAMICS

Generally, fracture toughness and fracture stress of ceramics depend on crack length, notch root radius and grain size. These three parameters are most important when assessing the integrity of structural ceramic members and developing high-performance ceramics. A new failure criterion called the process zone size failure criterion, has been proposed based on the existence of a crack-tip process zone. Using this criterion, it is shown that theoretical values are in good agreement with many test results quoted from many papers. It is concluded that this failure criterion is useful when evaluating crack length and notch root radius problems. The effect of grain size on both the fracture toughness and on the toughening mechanism is also considered.     

An adaptive method to treat number-sequences occurring in lifting surface calculations

In lifting surface calculations, assessment of convergence characteristics of number-sequences is a difficult task. A self-monitoring procedure needing no comparison with other schemes would be ideal. Among several kinds of convergence behaviour, the ‘N^?r type’ appears often in our practical, lifting surface, investigations. A formulation is proposed here to achieve automatically and without iteration a specified accuracy. This saves computation time, and may be termed an ‘adaptive method’. A new method of chordwise quadrature, ‘TrTr-NONEQ’, is presented as a model. This model indicates that the general formulation is reasonable. In addition, TrTr-NONEQ exhibits many advantages over other current methods such as those of Wagner, Gauss and Cunningham. Although still lacking theoretical justification, the present method seems to provide a basis for progress.