Double heterostructure and multiquantum-well lasers at 1.5?1.7 ?m grown by atmospheric pressure MOVPE

The first successful growth and fabrication of GaInAs/InP MQW and CW GaInAsP DH lasers by atmospheric pressure MOVPE is reported. Room-temperature CW operation of DH lasers was obtained by using the ridge-waveguide laser design, and threshold currents as low as 53 mA were measured. MQW lasers, which also operated at room temperature, were fabricated, and emission spectra obtained from these devices showed a clear spectral narrowing compared with the DH lasers together with a wavelength shift, in good agreement with theoretical predictions.     

The integration of object properties

Growth plate cartilage cell express receptors for, and are affected by both IGF-I and 1 alpha, 25(OH)2D3. The studies were undertaken to investigate interaction between these two hormone systems, that is, (i) to study effects of 1 alpha, 25(OH)2D3 on IGF-type 1 receptors (IGFIR), on IGF-I stimulated cell replication, colony formation, and on alkaline phosphatase activity (AP), and conversely, (ii) to study the effect of IGF-I on vitamin D receptor (VDR) expression on 1 alpha, 25(OH)2D3 stimulated growth parameters and on AP activity. Freshly isolated rat tibial chondrocytes were grown in monolayer cultures, (serum-free) or in agarose stabilized suspension cultures (0.1% FCS). Vitamin D receptor and IGFIR were visualized by immunostaining with the monoclonal antibody (mAb) 9A7 gamma and mAb alpha IR3, respectively, and quantitated by RT-PCR for mRNA and by Scatchard analysis using [3H]-1,25(OH)2D3 and [125I]-alpha IR3. Cell proliferation was measured by [3H]-thymidine incorporation, growth curves in monolayer cultures, and by colony formation in agarose-stabilized suspension cultures. IGF-I dose-dependently increased [3H]-thymidine incorporation. 1 alpha, 25(OH)2D3, but not 1 beta, 25(OH)2D3 was stimulatory at low ((10-12 M) and slightly inhibitory at high (10-8 M) concentrations. The effect of IGF-I was additive to that of 1 alpha, 25 (OH)2D3 [IGF-I 60 ng/ml, 181 +/- 12.7; 1 alpha, 25(OH)2D3 10(-12) M, 181 +/- 9.8%, IGF-I + 1 alpha, 25(OH)2D3, 247 +/- 16.7%, P < 0.05 by ANOVA] and specifically obliterated by polyclonal IGF-I antibody (AB-1). Interaction could also be confirmed in suspension cultures. IGFIR mRNA and [125I]-alphaIR3 binding was increased by low (10(-12) m) but not by high (10(-8) M) concentrations of 1 alpha, 25(OH)2D3. Homologous up-regulation by IGF-I (60 ng/ml) was specifically inhibited by AB-1 and markedly amplified by coincubation with 1 alpha, 25(OH)2D3 (10(-12)m). Immunostaining with alpha IR3 showed specific IGFIR expression in rat growth cartilage, but not liver tissue. Stimulation of chondrocytes with 1 alpha, 25(OH)2D3 or IGF-I suggested some increase of receptor expression in single cells, but the predominant effect was increased recruitment of receptor positive cells, Vitamin D receptor expression was markedly stimulated (fourfold) by IGF-I (60 ng/ml), but not IGF-II and inhibited by actinomycin D. This study shows that IGF-I and 1 alpha, 25(OH)2D3 mutually up-regulate their respective receptors in growth plate chondrocytes. In parallel, they have additive effects on cell proliferation and colony formation suggesting independent effector pathways.     

Epitaxial n+ layer GaAs mesa-finger interdigital surfacephotodetectors

Several varieties of interdigital surface photodetectors have been fabricated on semi-insulating GaAs using mesa-etched n⁺ epitaxial layers as the carrier collection electrodes. This structure provides a significant responsivity improvement over conventional metal-semiconductor-metal (MSM) photodiodes by eliminating the surface reflection of the metal fingers and by providing increased photoconductive gain. High-speed testing using 100-ps doubled Nd:YAG pulses gave FWHM (full width at half maximum) responses of less than 500 ps for a 4-μm finger width and spacing and showed minimal degradation from standard MSM detectors of the same surface geometry. By introducing no additional process steps, the mesa-finger detectors are also monolithically compatible with mesa-etched GaAs MESFET technology     

Psychotherapy and the recovery of memories of childhood sexual abuse: U.S. and British practitioners' opinions, practices, and experiences.

Psychotherapists were surveyed regarding clients' memories of childhood sexual abuse (CSA). The 3 samples were highly similar on the vast majority of measures. Respondents listed a wide variety of behavioral symptoms as potential indicators of CSA, and 71% indicated that they had used various techniques (e.g., hypnosis, interpretation of dreams) to help clients recover suspected memories of CSA . Across samples, 25% of the respondents reported a constellation of beliefs and practices suggestive of a focus on memory recovery, and these psychologists reported relatively high rates of memory recovery in their clients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dynamic polarization of C in ethylene-1,2-C2 glucol

The ¹³C nuclei in ethylene-1,2-¹³C₂ glycol have been dynamically polarized to 28%. The material appears suited for use as a polarized nuclear target for intermediate energy hadron+¹³C scattering experiments.