Coarsening rate of Β precipitates in Al-11Mg alloy

The coarsening rates of the Β precipitates in an Al-11 wt pct Mg alloy at 250 ‡C, 316 ‡C, and 330 ‡C aging temperatures were investigated. As predicted by the modified Lifshitz-Slyozov-Wagner (MLSW) theory of diffusion controlled particle coarsening, a linear dependence ofr ³ ont in the long time aging region was observed. Interfacial energies of 8.1, 1.8, and 1.7 J/m² for 250 ‡C, 316 ‡C, and 330 ‡C, respectively, were computed from these data using the MLSW theory. The high values of interfacial energy indicate that the Β precipitates are incoherent with respect to the Al matrix. The especially high value of interfacial energy and low activation energy for the precipitate coarsening at 250 ‡C suggest that significant short circuit diffusion occurs at this aging temperature.     

The genetic basis of epidermolysis bullosa simplex with mottled pigmentation

Epidermolysis bullosa simplex (EBS) is a group of autosomal dominant skin diseases characterized by blistering, due to mechanical stress-induced degeneration of basal epidermal cells. It is now well-established that the three major subtypes of EBS are genetic disorders of the basal epidermal keratins, keratin 5 (K5) and keratin 14 (K14). Here we show that a rare subtype, referred to as EBS with mottled pigmentation (MP), is also a disorder of these keratins. Affected members of two seemingly unrelated families with EBS-MP had a C to T point mutation in the second base position of codon 24 of one of two K5 alleles, leading to a Pro: Leu mutation. This mutation was not present in unaffected members nor in 100 alleles from normal individuals. Linkage analyses mapped the defect to this type II keratin gene (peak logarithm of odds score at phi = 0 of 3.9), which is located on chromosome 12q11-q13. This provides strong evidence that this mutation is responsible for the EBS-MP phenotype. Only conserved between K5 and K6, and not among any of the other type II keratins, Pro-24 is in the nonhelical head domain of K5, and only mildly perturbs the length of 10-nm keratin filaments assembled in vitro. However, this part of the K5 head domain is likely to protrude on the filament surface, perhaps leading to additional aberrations in intermediate filament architecture and/or in melanosome distribution that are seen ultrastructurally in patients with the mutation.     

Variables that distinguish elementary teachers who participate in school-based consultation from those who do not.

Examined variables that distinguished elementary teachers who participated in consultation from those who did not. 352 female elementary teachers completed questionnaires: 186 of the Ss reported they had participated in consultation with a school psychologist, and 166 reported that they had not. A stepwise discriminant function analysis using 8 teacher response variables found 5 variables that significantly distinguished the 2 groups: school psychologist offering help, teachers' scores on the Problem Solving Inventory, perceptions of psychologist training in problem solving, years of teaching experience, and perceptions that a school psychologist's training is different from that of a teacher's. Suggestions are offered to school psychologists for increasing teacher requests for consultation services. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phase transformations in condensed systems revisited: Industrial applications

The Institute of Metals Lecture was established in 1921, at which time the Institute of Metals Division was the only professional division within the American Institute of Mining and Metallurgical Engineers. It has been given annually since 1922 by distinguished people from this country and abroad. Beginning in 1973 and thereafter, the person selected to deliver the lecture will be known as the “Institute of Metals Division Lecturer and R.F. Mehl Medalist” for that year.     

Identification of two NF-kappa B sites in mouse CD95 ligand (Fas ligand) promoter: functional analysis in T cell hybridoma

Fas ligand (FasL) gene expression is critically involved in peripheral T cell tolerance and lymphocyte homeostasis. Previous studies have suggested that nuclear translocation of NF-kappaB during T cell activation is a critical event for FasL gene activation. In the present study we have identified two NF-kappaB sites (designated FasL-kappaB1 and FasL-kappaB2) on the promoter (approximately 700 bp) of FasL. The NF-kappaB sites were identified by electrophoretic mobility shift assay. Transient transfection reporter analyses showed that the FasL promoter activity was comparable between a construct that contains both sites and a shorter construct (433 bp) that contains only the FasL-kappaB1 site. Furthermore, elimination of FasL-kappaB1 by site-directed mutagenesis significantly inhibited FasL promoter activity. These observations provide strong evidence that NF-kappaB directly binds to the FasL-kappaB1 site and up-regulates FasL gene expression.     

Crack detection by resonant frequency measurements

The resonant frequency of 304 stainless steel specimens with a center-drilled hole has been measured as a function of fatigue cycles during crack initiation and propagation. Simultaneous measurements of crack lengths by scanning electron microscopy yield the resonant frequencyvs crack length. The change of resonant frequency is equivalent to the change of an effective elastic modulus. Analytical results for a “spring” model to predict the change in effective modulus due to the presence of cracks have been compared with results derived from resonant tests. In the model, the load transfer across the plane of the crack is represented by a distribution of springs of stiffness that depends on the crack length. Good agreement is observed between theory and experiment for cracks up to 500-μm long. The model may be used to obtain the crack length from resonance measurements. Formerly with the Materials Science and Engineering Department, Northwestern University, Evanston, IL 60208,     

Temporal Lobe Epilepsy and the Selective Reminding Test: The Conventional 30-Minute Delay Suffices.

Conventional memory assessment may fail to identify memory dysfunction characterized by intact recall for a relatively brief period but rapid forgetting thereafter. This study assessed learning and retention after 30-min and 24-hr delays on auditory and visual selective reminding tests (SRTs) in right (n = 20) and left (n = 22) temporal lobe epilepsy (TLE) patients and controls (n = 49). The left TLE group performed significantly worse than controls on all 3 trials of both tests. The right TLE group differed from the controls on all 3 visual SRT trials and on learning for the auditory SRT. There were no between-groups differences in rate of information lost at the 30-min versus the 24-hr delay. At the individual level, there was no difference in the percentage of patients versus controls who demonstrated isolated memory impairment at the 24-hr delay. Accelerated forgetting over 24 hr is uncommon in TLE patients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

改变衬底表面的晶向对非平面LPE生长结构的影响

改变衬底(100)面向[011]方向倾斜的角度α,可以得到不同的波导结构。