The effects of artificial asperities on crack closing behavior in quenched and tempered medium carbon steel

To better understand the effect of an asperity on crack closure behavior, K-CMOD relations were examined using artificial asperity/wedge, inserted into the fatigue crack in a three point bending specimen made of a hardened medium carbon steel. Experimental results revealed that the unloading phase of the K vs. CMOD curve exhibited a concave shape if soft artificial asperity (Al alloy) was inserted, signifying acceleration in the CMOD decrease at zero applied load. This was mainly related to elastic and plastic deformation in the wedge material during the unloading process. On the contrary, the linear unloading portion of K vs. CMOD was obtained as hard asperity (high carbon steel) was employed, which specified deceleration in the CMOD decrease at zero applied load, where the only elastic deformation in the asperity was affected. From their unloading curves, the severity of crack closure or ??K _eff value was found to be related to the strength of the asperity material. The values of ??K _eff were examined in two different ways, e.g., (i) the remote displacement method and (ii) the adjusted compliance ratio method (ACR). The ??K _eff value, measured using both approaches, decreases with increasing wedge strength, such as hardness and yield strength. The rate of reduction in ??K _eff was, however, changed depending on the manner of ??K _eff examination, in which the ??K _eff decreased at a higher rate for the compliance ratio method and at a lower rate for the remote displacement method. The reason for this is discussed in the present work.     

In situ measurement of material properties of lead zirconate titanate piezoelectric ceramics during cyclic mechanical loading

To better understand the material properties of lead zirconate titanate (PZT) ceramics, in situ mechanical and electrical properties have been investigated continuously during cyclic mechanical loading. The material properties are demonstrated to change as a function of applied maximum stress, with the effective elastic constant increasing with increase of the stress level. The increase of effective elastic constant is attributed to the domain structure of the PZT. 90° domain switching can occur anywhere in the sample, which makes the strain accumulate and leads to high values of the effective elastic constant. The domain switching characteristics are clearly revealed by electron back scattered diffraction analysis. The changes of the electrical properties (electromechanical coupling coefficient, piezoelectric constant and permittivity) are in the opposite sense because of the material strain (or material damage), caused by the change of domain orientation; the electrical properties are degraded with increasing cycle number and applied stress. Based upon the variation of the material properties, details of the damage characteristics in the PZT ceramics are discussed.     

Pulmonary alveolar proteinosis: diagnosis using routinely processed smears of bronchoalveolar lavage fluid

AIMS: For the diagnosis of pulmonary alveolar proteinosis from bronchoalveolar lavage specimens it is normally necessary to make an ultrastructural examination. However, this is thought to be impractical for bronchoalveolar lavage specimens that have been routinely fixed in ethanol. In the present study, bronchoalveolar lavage cytology smears on slide glasses were examined directly ultrastructurally to make a diagnosis of pulmonary alveolar proteinosis. METHODS: Bronchoalveolar lavage smears from three pulmonary alveolar proteinosis patients were stained with Papanicolaou and periodic acid-Schiff (PAS) for identification of amorphous globular structures. Subsequently, they were refixed with glutaraldehyde and osmium tetroxide, and embedded in epoxy resin. Ultrathin sections were cut and examined ultrastructurally. RESULTS: Papanicolaou stained specimens from pulmonary alveolar proteinosis patients contained scattered amorphous or granular globules, 20-50 microns in diameter, which were PAS positive. Ultrastructural examination of the globules revealed multilamellated structures, characteristic of pulmonary alveolar proteinosis, in all cases. CONCLUSIONS: In general, it is thought that the morphological diagnosis of pulmonary alveolar proteinosis from bronchoalveolar lavage specimens requires both cytological and ultrastructural examination. However, the amorphous globules evident on cytology smears proved to contain multilamellated structures so that they can themselves be used as diagnostic evidence.     

Involvement of interleukin-1 in the development of ulcerative colitis induced by dextran sulfate sodium in mice

Dextran sulfate sodium (DSS)-induced colitis in mice has been recognized as a model for human ulcerative colitis. Using this model, the effects of anti-murine interleukin 1beta (IL-1beta) antibodies (anti-muIL-1beta) and recombinant murine IL-1 receptor type I (rmuIL-1R) on the development of colitis were examined to determine whether IL-1 plays a role in colitis. Furthermore, RT-PCR amplification was used to examine for the presence of mRNAs for IL-1alpha and IL-1beta in the large intestine. In mice with colitis induced by DSS, administration of anti-muIL-1beta (5 mg/kg, once/week, i.p.) significantly suppressed body weight loss and shortening of the large intestine. Administration of rmuIL-1R (0.2 mg/kg or 1.0 mg/kg, once/day, i.v.) significantly suppressed shortening of the large intestine. Expression of mRNAs for IL-1alpha and IL-1beta was observed in the large intestine of mice which received distilled water containing 3% DSS for 5 days. The expression tended to increase in mice which received DSS for 11 days. In contrast, mRNA expression was not observed in mice which received distilled water without DSS. These results clearly demonstrate that IL-1 is involved in the development of DSS-induced colitis in mice and suggest that downregulation of IL-1 might be useful for the treatment of patients with ulcerative colitis.     

Gain characteristics of an Er3+-doped multicomponentglass single-mode optical fiber

Experimental results on gain characteristics of an Er³⁺-doped multicomponent glass single-mode optical-fiber amplifier are reported. This amplifier shows a gain spectrum with twin gain peaks of 1.535 and 1.543 μm, providing a broadened gain bandwidth. The apparent 6-dB gain bandwidth is 12 nm. Furthermore, the signal gain of 17 dB and 15-mW pump power is realized at a signal wavelength of 1.536 μm, and a signal gain coefficient of 1.4 dB/mW is achieved     

Significant correlation of telomerase activity in lung adenocarcinomas with cell differentiation and chromosome aberration

OBJECTIVE: To assess the long-term safety of adjunctive corticosteroids in the treatment of Pneumocystis carinii pneumonia (PCP). DESIGN: Analysis of data from a large prospective observational database. SETTING: HIV clinic at a large urban teaching hospital. PATIENTS: One hundred seventy-four patients who developed PCP after being enrolled in the database. RESULTS: Fifty-three patients (30%) received adjunctive corticosteroids and 121 (70%) did not. Survival did not differ between groups after adjusting for CD4 count (relative risk for adjunctive corticosteroids = 0.74, p = 0.13). There were no differences in the incidence of cytomegalovirus disease (adjunctive corticosteroids: 18.5 cases per 100 person-years vs no adjunctive corticosteroids: 15.7, p = 0.22), Mycobacterium avium complex (23.4 vs 27.0, p = 0.73), cryptococcal meningitis (1.8 vs 4.1, p = 0.58), toxoplasmosis (3.6 vs 11.0, p = 0.28), Kaposi's sarcoma (1.8 vs 2.2, p = 0.92), herpes simplex (27.1 vs 42.7, p = 0.66), herpes zoster (3.8 vs 6.9, p = 0.71), oropharyngeal candidiasis (18.9 vs 10.9, p = 0.09), or non-Hodgkin's lymphoma (3.5 vs 4.2, p = 0.92). Esophageal candidiasis was more common among adjunctive corticosteroid recipients (45.1 vs 26.6, p = 0.01). Results were similar for time to development of opportunistic conditions. CONCLUSIONS: Adjunctive corticosteroids do not increase mortality or the risk of most common HIV-associated complications.     

The development of a visual system for the detection of obstructions for visually impaired people

In this paper, the author presents a new visual system that can aid visually impaired people in walking. The system provides object information (that is, shape and location) through the sense of touch. This visual system depends on three different components: (i) an infrared camera sensor that detects the obstruction, (ii) a control system that measures the distance between the obstruction and the sensor, and (iii) a tooling apparatus with small pins (ϕ1 mm) used in forming a three-dimensional shape of the obstruction. The pins, arranged on a 6×6 matrix, move longitudinally between the retracted and extended positions based on the distance data. The pin extends individually, while the pin tip reflects the object’s outer surface. The length of the pin from the base surface is proportional to the distance of the sensor from the obstruction. An ultrasonic actuator, controlled at a 15Hz frame rate, is the driving force for the pin movement. The tactile image of the 3D shape can provide information about the obstruction.     

Development of SPring-8 vacuum system

SPring-8 storage ring has been available for user operation with low emittance and extreme stability for over 10 years. However there occurred some problems in the components of the storage ring due to high-brightness synchrotron radiation (SR) and low-emittance operation. On the vacuum system of the storage ring, an accurate pressure could not be measured near the photon absorber due to scattered high-energy SR to the gauge head. High-energy SR activated dissolved oxygen in cooling water, and the activated dissolved oxygen corroded the inside of the photon absorbers in SR irradiation part. Air leakage occurred at an injection chamber due to impact by a small-size electron beam produced by low-emittance operation.We investigated the cause of the aforementioned difficulties with the vacuum system and prescribed the treatments described in this paper. In addition, we are making continual efforts at further system upgrades such as developing an RF shield that suppresses temperature increase in the shield in possible high-current operation.     

Erbium-doped fibre amplifiers with an extremely high gain coefficient of 11.0 dB/mW

A gain coefficient of 11.0 dB/mW is obtained using 0.98 mu m laser diode pumped erbium-doped fibre amplifiers with a low erbium concentration of 81 p.p.m. and a high relative refractive index difference of 1.88%.<>     

Detection of the Epstein-Barr virus genome in cervical neoplasia is closely related to the degree of infiltrating lymphoid cells: a polymerase chain reaction and in situ hybridization approach

To cast light on the significance of Epstein-Barr virus (EBV) infection in cervical tumorigenesis, 44 cervical intraepithelial neoplasia (CIN) types I/II, and 70 CIN III lesions, 60 invasive squamous cell carcinomas (ISCC), and 20 normal cervical samples were investigated by polymerase chain reaction (PCR) and RNA in situ hybridization (RISH) assays. The EBV genome was detected by PCR using primers targeting the IR region in three (6.8%) of the CIN I/II, 15 (21.4%) of the CIN III and 13 (21.7%) of the ISCC lesions, while using an EBER oligonucleotide probe RISH revealed positive signals in infiltrating lymphocytes located in the cervical stroma, but not in dysplastic or tumor cells. There was a significant correlation between the presence of EBV DNA and the degree of lymphoid cell infiltration (P = 0.0223). In contrast, none of the normal cervical samples that were without inflammation demonstrated any EBV infection. Thus, the results indicated that a positive result for EBV on PCR may be simply dependent on the amount of lymphocytes in cervical stroma, suggesting that this virus does not play a major role in the etiology of cervical neoplasia.