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Optoelectronic chromatic dispersion (OED) has recently been shown to be a significant source of chromatic dispersion in photodiodes. We characterize the OED in a commercial germanium PN-type photodiode and determine the optimum conditions for maximum OED sensitivity and wavelength monitoring. A peak OED sensitivity of 1 deg/nm is measured in a spectral range of 1550–1558 nm with 4 MHz modulation. We also demonstrate an application of OED in fiber Bragg grating (FBG) interrogation. Quasi-static and vibration strains are monitored, with a spectral and strain sensitivity of 1.25pm/Hz and 1.08µε/Hz, respectively. Photodiode OED can form the basis of inexpensive chip-scale grating-less spectral analysis.

The deformation behavior and microstructural evolution of ultrafine- (UFG) and fine-grained (FG) Cu during the dynamic tensile extrusion (DTE) process were investigated. The DTE tests were conducted with identical projectile velocities using an all-vacuum gas gun. The DTE ductility increases as the grain size increases, in contrast to the previous outcome with coarse-grained Cu exhibiting that the ductility increased with a decrease in the grain size. The fragments were softly recovered and were examined by a micro-Vickers hardness test and microstructural characterization assessments. The hardness profiles of the fragments exhibit a drastic decrease in the UFG-B remnant, while hardness variations are found in the middle fragments for FG-200. A strong dual <001> + <111> texture is developed during the DTE regardless of the UFG and FG sizes. The UFG-B fragments show that the <111> fibers are replaced by the <001> fibers as a result of meta-dynamic recrystallization (mDRX), while the <111> fibers in FG-200 saturate without any extensive reduction. Evidence of the mDRX was found in an analysis of the misorientation-angle distribution, grain morphology, and grain orientation spread. A numerical simulation reveals that the mDRX can occur due to adiabatic heating, with the faster kinetics in the UFG-B originated from the accumulation of higher levels of deformation energy during the DTE process. The present study also confirms that occurrence of mDRX in the UFG and FG Cu triggers a ductile failure and local necking with a decrease in the DTE ductility.

The hereditary breast and ovarian cancer gene, BRCA1, encodes a large polypeptide that contains the cysteine–rich RING motif, a zinc–binding domain found in a variety of regulatory proteins. Here we describe a novel protein that interacts in vivo with the N–terminal region of BRCA1. This BRCA1–associated RING domain (BARD1) protein contains an N–terminal RING motif, three tandem ankyrin repeats, and a C–terminal sequence with significant homology to the phylogenetically conserved BRCT domains that lie near the C terminus of BRCA1. The BARD1/BRCA1 interaction is disrupted by BRCA1 missense mutations that segregate with breast cancer susceptibility, indicating that BARD1 may be involved in mediating tumour suppression by BRCA1.

The BRCA1tumor suppressor encodes a polypeptide with two recognizable protein motifs: a RING domain near the N terminus and two tandem BRCT domains at the C terminus. Studies of tumor-associated mutations indicate that the RING and BRCT sequences are required for BRCA1-mediated tumor suppression. In addition, recent work has shown that BRCA1 is a potent regulator of RNA transcription and that the BRCT domains are also essential for this activity. Therefore, we used the Sos recruitment system to screen for proteins that bind this critical region of BRCA1. Our results show that the BRCT domains interact in vivowith CtIP, a protein originally identified on the basis of its association with the CtBP transcriptional co-repressor. This finding suggests that BRCA1 regulates gene expression, at least in part, by modulating CtBP-mediated transcriptional repression. Moreover, the in vivointeraction between BRCA1 and CtIP is completely ablated by each of three independent tumor-associated mutations affecting the BRCT motifs of BRCA1. These results indicate that the BRCA1-CtIP interaction may be required for tumor suppression by BRCA1.

Dynamic tensile extrusion (DTE) tests with the strain rate order of ~105 s[?]1 were conducted on coarse grained (CG) Cu and ultrafine grained (UFG) Cu. ECAP of 16 passes with route Bc was employed to fabricate UFG Cu. DTE tests were carried out by launching the sphere samples to the conical extrusion die at a speed of ~475 m/sec in a vacuumed gas gun system. UFG Cu was fragmented into 3 pieces and showed a DTE elongation of ~340%. CG Cu exhibited a larger DTE elongation of ~490% with fragmentation of 4 pieces. During DTE tests, dynamic recrystallization occurred in UFG Cu, but not in CG Cu. In order to examine the DTE behavior of CG Cu and UFG Cu under very high strain rates, a numerical analysis was undertaken by using a commercial finite element code (LS-DYNA 2D axis-symmetric model) with the Johnson - Cook model. The numerical analysis correctly predicted fragmentation and DTE elongation of CG Cu. But, the experimental DTE elongation of UFG Cu was much smaller than that predicted by the numerical analysis. This difference is discussed in terms of microstructural evolution of UFG Cu during DTE tests.