Microstructure of the interface in magnesium alloy to aluminium alloy dissimilar joints produced by friction stir welding

Friction stir welding (FSW) is a process that was developed by the UK Welding Institute (TWI) in 1991.¹ Because of its status as a solid-phase joining process operating at a temperature below the melting point of the materials being joined, FSW usually generates less residual stress than fusion welding, being also advantageously free from fume, porosity, and solidification cracking. The mechanical properties of welds are equivalent or superior to those of conventional welds and offer a high level of reliability. Other merits of FSW include relatively low equipment costs, low operating costs, and no required training. For this reason, in the decade or so since the principle of FSW was invented, the process has seen a number of practical applications in railway and ship structures as well as for rocket fuel tanks in the aerospace field² and continues to draw considerable attention by the engineering industry worldwide. The foregoing applications, however, all refer to components produced from aluminium alloys.     

Effect of training program based on anaerobic threshold in the early phase after acute myocardial infarction

We devised a new physical training program on the basis of anaerobic threshold for rehabilitation in the early phase of acute myocardial infarction. Forty-four patients were divided into two groups, control and training. We measured the left ventricular ejection fraction using nuclear stethoscopy during the treadmill test and calculating radioactive cardiac output. In the training group, anaerobic threshold and exercise time to the anaerobic threshold point were significantly increased, and stroke volume at rest measured by the dye dilution method increased significantly. Radioactive cardiac output during exercise also increased after the exercise therapy. These results indicate that the rehabilitation program consisting of physical training based on the anaerobic threshold is effective.     

Changes in volatile flavour components of soybeans during roasting

Volatile concentrates were prepared from whole soybeans, roasted at 200°C for 10, 20 and 30 min, by steam distillation under reduced pressure followed by ether extraction, and analysed by gas chromatography and gas chromatography-mass spectrometry, in comparison with the volatile concentrate from raw soybean flour.Major flavour components of raw soybean, such as n-hexanol, 1-octen-3-ol and n-hexanal, decreased during the course of roasting, but the rate of this decrease was not rapid, especially between 10 and 20 minutes' roasting. During the roasting period, alkylated pyrazines, oxygenated furans, oxygenated pyrroles and phenols were formed or increased markedly. On the other hand, sensory evaluation showed that a flavour change to ‘desirable’ from ‘beany’ or ‘objectionable’ occurred between 10 and 20 minutes' roasting. These results suggest that roast flavour masks the ‘beany’ flavour in soybean.     

Measurement of erosion yields for a SiC surface on H+, D+ and Ar+ bombardment

Changes in the distribution of silicon solute in a 99.8% pure nickel crystal after 75 keV Ni⁺ ion bombardment at 16°C and 500°C, are reported. The concentration depth profiles were measured by simultaneous sputter-profiling and secondary ion mass spectrometry (SIMS). At 16°C the results are satisfactorily explained by the formation and subsequent migration to sinks of nickel interstitial-silicon complexes. The same mechanisms can be used to explain the results obtained at 500°C but the effect observed could also be due to the migration of vacancy-silicon complexes to sinks and the possibility that both mechanisms occur simultaneously cannot be ruled out.     

Optimally weighted wavelet transform based on supervised training for detection of microcalcifications in digital mammograms

We are developing a computer-aided diagnosis (CAD) scheme for detection of clustered microcalcifications in digital mammograms. The use of an empirically chosen wavelet and scale combination for detection of microcalcifications as an initial step of the CAD scheme has been reported by us previously. In this study, we developed a technique for optimizing the weights at individual scales in the wavelet transform to improve the performance of our CAD scheme based on the supervised learning method. In the learning process, an error function was formulated to represent the difference between a desired output and the reconstructed image obtained from weighted wavelet coefficients for a given mammogram. The error function was then minimized by modifying the weights for wavelet coefficients by means of a conjugate gradient algorithm. The Least Asymmetric Daubechies' wavelets were optimized with 297 regions of interest (ROIs) as a training set by a jackknife method. The performance of the optimally weighted wavelets was evaluated by means of receiver-operating characteristic (ROC) analysis by use of the above set of ROIs. The analysis yielded an average area under the ROC curve of 0.92, which outperforms the difference-image technique used in our existing CAD scheme, as well as the partial reconstruction method used in our previous study.     

Computer-aided diagnosis in chest radiography. Preliminary experience

RATIONALE AND OBJECTIVES: Computer-aided diagnosis (CAD) schemes for chest radiography are being developed with which to alert radiologists to possible lesions, and thus potentially improve diagnostic accuracy. However, CAD schemes have not been tested on a large number of clinical cases. The authors identify design parameters that would be required for development of an intelligent workstation. METHODS: Computer-aided diagnosis programs were applied for the automated detection of lung nodules, cardiomegaly, and interstitial infiltrates to 310 consecutive chest radiographs, and were analyzed for potential usefulness and limitations. Computer-aided diagnosis output was evaluated by radiologists and physicists for accuracy and technical problems, respectively. RESULTS: Approximately 70% of the results were judged to be potentially acceptable; however, the number of false-positive findings was relatively high. Technical problems included failure to detect subtle abnormalities and the occurrence of false-positive detections caused by normal anatomical structures. CONCLUSION: Computer-aided diagnosis has the potential to be a valuable aid to radiologists in clinical practice, if certain technical problems can be overcome and if optimal operating points can be defined for clinical use.     

CD7, HLA-DR, CD38 positive acute undifferentiated leukemia with subcutaneous tumor and thymoma

A case of acute undifferentiated leukemia (AUL), accompanied by subcutaneous tumor and thymoma is reported. The analysis of immunophenotype showed that the leukemic blasts were positive for CD7, HLA-DR, CD38 and CD34 in 17.5% but negative results were obtained for other lymphoid and myeloid antigens. The leukemic blasts had a rearranged immunoglobulin heavy chain (IgH) gene and T cell receptor delta (TCR-delta) chain gene chromosomal abnormality, 47, XY, +8, t(13; 17) (q12; q21), -17, +M was observed. In general, the CR rate is low and prognosis is poor in patients with AUL. In our case, CR was not achieved by the therapy with JALSG-ALL87 protocol, but was achieved by subsequent treatment with high dose ara-C therapy and combination chemotherapy including intermediate-dose ara-C, mitoxantrone, etoposide and prednisolone.