Application of a NDI method using magneto-optical film for micro-cracks

Leakage magnetic flux is occurred in the cracked area of magnetized specimens, and also it changes the magnetic domain area of the magneto-optical film positioned on the specimen. It causes the change of the optical permeability of the magnetic domain on the crack area. So crack images can be obtained easily using this principle. On the other hand, utilizing a laser in this method makes possible to perform a remote sensing by detecting the light intensity contrast between cracked area and normal area. This paper shows the application of non-destructive inspection system taking advantage of magneto-optical method for micro-cracks and presents examples applied to the several types of specimens having fatigue cracks and fabricated cracks using this method. Also the authors prove the possibility of this method as a remote sensing system under the oscillation load considering application to real fields.     

Effects of scatter and attenuation correction on quantitative assessment of regional cerebral blood flow with SPECT

The pyruvate dehydrogenase complex (PDC) plays a key role in the anaerobic mitochondrial metabolism of the parasitic nematode Ascaris suum. A cDNA coding for an A. suum pyruvate dehydrogenase kinase (APDK) has been cloned and sequenced from poly(A)+ RNA isolated from adult A. suum muscle.2 APDK exhibited significant sequence identity to mammalian PDKs. Nucleotide sequence analysis of the APDK cDNA revealed a 22-nucleotide spliced leader, characteristic of many nematode mRNAs, a 5'-UTR of 6 nucleotides, an open reading frame of 1197 nucleotides, and a 3'-UTR of 101 nucleotides that included a putative polyadenylation signal. The open reading frame predicted a protein of 399 amino acids with a molecular weight of 45,402 that included a putative 18-aminoacid leader peptide. Recombinant APDK (rAPDK) was functionally expressed in Escherichia coli with a his tag at its N-terminus and purified to apparent homogeneity on Ni-NTA-agarose. Recombinant APDK was a dimer and was not autophosphorylated and its activity was stimulated in the presence of APDK-deficient adult A. suum muscle PDC presumably by the binding of APDK to the dihydrolipoyl transacetylase (E2) core of the complex. After binding to the core, rAPDK activity was stimulated by elevated NADH/NAD+ and acetyl CoA/CoA ratios within the same ranges as observed for the native APDK. Immunoblotting suggested that native APDK focused as a series of 43-kDa spots (pI 6.1-6.8) on two-dimensional gels of the purified adult A. suum muscle PDC.     

Hypertrophic cranial pachymeningitis with spinal epidural granulomatous lesion

A 67-year-old woman with a one-year history of tinnitus and headache had multiple cranial nerve palsies of V, VII, VIII, IX, X, XI and spastic paraparesis. She also had a secretory otitis media. Gd-DTPA-enhanced magnetic resonance imaging (MRI) revealed hypertrophy of the dura of the posterior fossa and spinal epidural mass which extended from C7 to T10. A biopsy of the epidural mass showed chronic granulomatous change. These lesions were completely cured with administration of antibiotics. We believe this case of double-lesion of hypertrophic cranial pachymeningitis and spinal epidural granulomatous lesion originated from a bacterial infection secondary to the secretory otitis media.     

Endothelial nitric oxide synthase gene polymorphism and hypertension

Nitric oxide (NO) is produced by endothelial cells and serves as a potent vasodilator. Several lines of evidence have shown that NO plays an important role in the regulation of blood pressure and regional blood flow. Endothelial NO synthase (eNOS) gene polymorphisms exhibit a positive association in myocardial infarction and smoking-dependent risk of coronary artery disease. However, the relationship between eNOS gene polymorphisms and hypertension is controversial. To examine the possible involvement of the eNOS gene in the genetic basis for hypertension, we identified genotypes for 2 eNOS gene polymorphisms in 166 hypertensive and 174 normotensive populations in Aomori prefecture, in northern Japan. The specific genotypes for Glu298Asp missense variant and variable numbers of tandem repeats in intron 4 (eNOS 4b/4a) were isolated using allele specific gene amplification and restriction fragment length polymorphism. The 298Asp variant was significantly correlated to hypertension in these groups (odds ratio, 1.8; 95% confidence interval, 1.1-3.2). The allelic frequencies of 298Asp for Glu298 in hypertensive patients were significantly higher than those in normotensive subjects (0.136 vs 0.083, p < 0.05). However, disequilibrium of eNOS4b/4a was absent between these 2 groups. These results suggest that Glu298Asp is a genetic susceptibility factor for hypertension.     

Acoustic emission rating parameter for prediction of tearing instability in structural materials

A comparative study is made of the relative acoustic emission activity during fracture toughness tests in different steel and aluminum alloys. The role that acoustic emission can be expected to play in the detection and measurement of crack extension processes is experimentally demonstrated. A new acoustic emission rating parameter is proposed to predict tearing instability of elastic-plastic crack growth in structural materials. The proposed severity parameter is used to discuss conditions for structural instability in some intermediate pressure vessels. The paper keynotes the need for close interaction between the acoustic emission and fracture mechanics technologies for predicting and preventing the failure of structural system. Finally, some thoughts on a general structural integrity plan are presented.     

Three-dimensional micro-structures consisting of high aspect ratio inclined micro-pillars fabricated by simple photolithography

This paper presents a fabrication method of three-dimensional micro-structures consisting of high aspect ratio inclined micro-pillars using simple photolithography. The width and height of micro-pillars were 10 m and 200 m (the aspect ratio was about 20). The SU-8 coated on the Cr patterned Pyrex glass substrate was exposed from the backside with an angle to fabricate inclined micro-pillars. The 3-D micro-structures were fabricated by repeating the backside exposure with different angles. The shape of the micro-structure was defined by the number of exposures and the UV irradiation angles. The complicated micro-structures were fabricated by multi-angle exposures around two axes, as well as around one axis.This work was supported by: the Japanese Ministry of Education, Culture, Sport, Science and Technology Grant-in-Aids for COE Research of Waseda University, Scientific Research Priority Area (B) No. 13124209, Japan Society for the Promotion Science Grant-in-Aids for Creative Scientific Research No. 13BS0024, Nanotechnology Support Project of the Ministry of Education, Culture, Sports, Science and Technology (MEXT) Japan, 21COE Practical Nano-Chemistry from MEXT Japan and Waseda University Grant for Special Research Project Individual Research No. 2002A-865.     

A radio-telemetry system with a shape memory alloy microelectrode for neural recording of freely moving insects

A radio frequency (RF) telemetry system with a shape memory alloy microelectrode was designed and fabricated. The total size and weight are 15 mm x 8 mm and 0.1 g, respectively. Since the telemeter is small and light enough to be loaded on a small animal such as an insect, the system can be used for the neural recording of a freely moving insect. The RF-telemeter can transmit signals by frequency modulation transmission at 80-90 MHz. The transmitted signals can be received up to about 16 meters away from the telemeter with a high signal-to-noise ratio. The neural activity can be detected without attenuation by using an instrumentation amplifier with its input impedance set to 2 Mohms at 1 kHz. The telemeter was loaded on a cockroach and the neural activity during a free-walk was successfully measured through this telemetry system.     

Characterization of the chemical conversion films that form on Mg−Al alloy in colloidal silica solution

Chemical conversion treatment of Mg−Al alloy (AZ91) using colloidal silica as an alternative to chromate conversion was investigated as a function of solution pH, temperature, solution conditions, and treatment time. The solution used for the colloidal silica coating consisted of colloidal silica, titanium sulfate, and cobalt ions to maintain good anti-corrosion and adhesion properties. Adding CoSO₄ to the colloidal silica solution enhanced the adhesion force between the silica film and magnesium substrate. The optimum conditions for the chemical conversion treatment solution were pH 2, 90-sec treatment, and 25°C.