Evolution of spall-damage in iron caused by repeated plate impacts: Ultrasonic evaluation.

This paper focuses on the developed of spall-damage that occurs in pure iron as a result of repeated impact. The employed low-frequency scanning acoustic microscopy (LF-SAM) observations combined with the measurements of ultrasonic wave velocity, attenuation, backscattering intensity and amplitude spectrum of the reflected wave, enabled us to provide a nondestructive evaluation. The spall-damage distribution was analyzed in the C-scan images, and we found the spall-damage increase with impact stress when the latter exceeds the characteristic spall-threshold stress. Moreover, we recorded the decreased sound velocity, amplitude ratio, and the increase of backscattering intensity, significant attenuation (the high frequency component of the reflected wave) for enhanced impact stress. It was also demonstrated that the tiny cracks generated in iron develop significantly during subsequent impacts either with lower or higher impact stress. Since the presented results concern for the first time the multiple-impact experiments, we contend that the applied ultrasonic investigations constitute the effective method of nondestructive spall-damage evaluation.

Ultrasound-guided gradual reduction using flexion and abduction continuous traction for developmental dysplasia of the hip: a new method of treatment.

We describe our experience in the reduction of dislocation of the hip secondary to developmental dysplasia using ultrasound-guided gradual reduction using flexion and abduction continuous traction (FACT-R). During a period of 13 years we treated 208 Suzuki type B or C complete dislocations of the hip in 202 children with a mean age of four months (0 to 11). The mean follow-up was 9.1 years (five to 16). The rate of reduction was 99.0%. There were no recurrent dislocations, and the rate of avascular necrosis of the femoral head was 1.0%. The rate of secondary surgery for residual acetabular dysplasia was 19.2%, and this was significantly higher in those children in whom the initial treatment was delayed or if other previous treatments had failed (p = 0.00045). The duration of FACT-R was significantly longer in severe dislocations (p = 0.001) or if previous treatments had failed (p = 0.018). This new method of treatment is effective and safe in these difficult cases and offers outcomes comparable to or better than those of standard methods.

Ultraviolet photochemical reaction of [Fe(III)(C2O4)3](3-) in aqueous solutions studied by femtosecond time-resolved X-ray absorption spectroscopy using an X-ray free electron laser.

Time-resolved X-ray absorption spectroscopy was performed for aqueous ammonium iron(III) oxalate trihydrate solutions using an X-ray free electron laser and a synchronized ultraviolet laser. The spectral and time resolutions of the experiment were 1.3 eV and 200 fs, respectively. A femtosecond 268 nm pulse was employed to excite [Fe(III)(C2O4)3](3-) in solution from the high-spin ground electronic state to ligand-to-metal charge transfer state(s), and the subsequent dynamics were studied by observing the time-evolution of the X-ray absorption spectrum near the Fe K-edge. Upon 268 nm photoexcitation, the Fe K-edge underwent a red-shift by more than 4 eV within 140 fs; however, the magnitude of the redshift subsequently diminished within 3 ps. The Fe K-edge of the photoproduct remained lower in energy than that of [Fe(III)(C2O4)3](3-). The observed red-shift of the Fe K-edge and the spectral feature of the product indicate that Fe(III) is upon excitation immediately photoreduced to Fe(II), followed by ligand dissociation from Fe(II). Based on a comparison of the X-ray absorption spectra with density functional theory calculations, we propose that the dissociation proceeds in two steps, forming first [(CO2 (•))Fe(II)(C2O4)2](3-) and subsequently [Fe(II)(C2O4)2](2-).

Engineering neoglycoproteins with multiple O-glycans using repetitive pentapeptide glycosylation units.

Controlled protein remodeling with O-linked glycans has been limited by our incomplete understanding of the process of glycosylation. Here we describe a secretable fibroblast growth factor (FGF) with multiple mucin-type O-glycans produced by introducing a minimum pentapeptide glycosylation unit in a decarepeat format at its N- or C-terminus. Expressed in Chinese hamster ovary cells, chemical and biochemical analyses of the resultant proteins (Nm10-FGF and Cm10-FGF, respectively) demonstrated that all O-glycosylation units were glycosylated and the dominant structure was sialylated Gal[beta1-3]GalNAc. This indicates that minimum O-glycosylation unit in multirepeat format serves as a remarkably efficient acceptor in CHO cells. The Nm10-FGF and Cm10-FGF proteins maintained the mitogenic activity to vascular endothelial cells. In addition, intact Cm10-FGF and its desialylated form interacted with several lectins in the same way as mucin-type glycoproteins. The intact Cm10-FGF with multiple sialylated O-glycans exhibited a longer lifetime in circulating blood, whereas the Cm10-FGF with desialylated O-glycans exhibited a shorter lifetime than the deglycosylated form of Cm10-FGF. Our approach would thus appear to be highly effective for engineering neoglycoproteins, the characteristics of which are determined by their multiple mucin-type O-glycans.

The H1Sigma+g (v = 0 and 1) and EF1Sigma+g (v = 28 and 32) States of D2: Term Values and Fluorescence Lifetimes.

The extreme ultraviolet-visible double resonant excitation method was applied to the gerade Rydberg states of D2 molecules. Tunable coherent extreme ultraviolet radiation near 103 nm prepared D2 in the B1Sigma+u (v = 7, J) state. Visible laser light subsequently brought them to the H1Sigma+g (v = 0 and 1), EF1Sigma+g (v = 28 and 32), and GK1Sigma+g (v = 2 and 5) states. Our term values for the GK1Sigma+g state were in complete agreement with previous values, while deviations beyond the experimental error were found for the H1Sigma+g (v = 1) and EF1Sigma+g (v = 28 and 32) states. The fluorescence lifetimes, measured under a collision-free environment for the first time, were in reasonable agreement with ab initio calculations. Copyright 1998 Academic Press.

Molecular analysis of the inheritance of the S-5 locus, conferring wide compatibility in Indica/Japonica hybrids of rice (O. sativa L.).

RFLP analysis was conducted on a population derived from a three-way cross to determine the location of the hybrid sterility locus, S-5, in relation to mapped molecular markers and to identify markers that would be useful for selection in breeding. S-5 is of interest to rice breeders because it is associated with spikelet sterility of F1 hybrids in Indica/Japonica crosses. Identification of an S-5 allele which confers fertility in Indica/Japonica hybrids when introgressed into either the Indica or the Japonica parent has been reported. Varieties carrying this S-5 (n) allele are known as "wide compatibility varieties (WCV)". Our data suggests that RFLP marker RG213 on chromosome 6 is closely linked to the S-5 locus and can be efficiently used to identify wide compatibility (WC) lines. RG213 is a single-copy genomic clone that detects three bands of different molecular weights in DNA from Japonica ('Akihikari') and Indica ('IR36') varieties and WC line ('Nekken 2'). We demonstrate that the three alleles detected by this marker could be used to trace the inheritance of the "wide compatible" phenotype in breeders' material.