Fabrication of HgBa2CuO x superconductor under atmospheric pressure

We report a simple and safe technology where rather pure Hg-1201 phase superconducting bulk samples can be fabricated. The pellet was heated at about 700°C for only 30 min in open air under atmospheric pressure. We have found that a dehydration process (heating for 20 h at 250°C) is a crucial procedure for success in forming the Hg-1201 phase.     

Policy Analysis, Peer Reviewed: Toxics Release Inventories: Opportunities for Improved Presentation and Interpretation

Industrial Regulations.     

Synthesis of 11-substituted androstenediones and testosterones as human decidual cell growth inhibitors

11 alpha-Hydroxytestosterone (1a), 11 beta-hydroxytestosterone (1b), 11 alpha-methoxytestosterone (1c), 11 beta-methoxytestosterone (1d), 11-ketotestosterone (1e), and delta 9(11)-testosterone (1f) were synthesized from hydrocortisone (4b) or 11-epi-hydrocortisone (4a). The six target compounds, together with 11 alpha-methoxyandrostenedione (2c), 11 beta-methoxyandrostenedione, (2d) and their lead compound, testosterone (1), were found to effectively inhibit the growth and differentiation of human decidual cells in culture. There is no observable binding of these compounds to estrogen receptor of rabbit uterus. The introduction of a polar group (e.g., hydroxyl and carbonyl) to C-11 of androstenes decreases both the relative binding affinities to progesterone receptor and the inhibitory effects on human decidual cell growth, while the methylation of 11-hydroxyl group minimizes these effects. The similar effects of a polar group at C-11 of testosterone (1) on the inhibitory effects on human decidual cell growth and the relative binding affinities to progesterone receptor of rabbit uterus may suggest that one of the mechanisms of human decidual cell growth inhibition by these compounds is the anti-progestational activity of these androgens.     

Characterization of human gamma 4 switch region polymorphisms suggests a meiotic recombinational hot spot within the Ig locus: influence of S region length on IgG4 production

Human gamma4 gene RFLPs, revealed after BamHI digestion, show IGHG4 alleles of 9.0 (9.2), 9.4, and 9.6 kb at various frequencies in different ethnic populations. Studies in immunodeficient individuals have previously suggested that the 9.4 BamHI allele is associated with a higher serum level of IgG4 than the 9.0 (9.2) BamHI allele, but it is not clear whether this is associated with the S region itself or other control elements. In addition, a duplication of the 9.4-kb gamma4 allele has recently been observed in a high proportion of normal donors. We therefore undertook a study of the structural basis for the difference in Ab levels in the various gamma4 alleles. We demonstrate that the Sgamma4 alleles differ in length due to deletions and insertions of a varying number of 79-bp Sgamma4 repeat units. Two novel RFLPs, 8.8 and 9.1 kb, were also observed. The alleles are likely to be generated by unequal crossing over, and the breakpoints cluster in Sgamma4 repeat units that contain chi-like motifs, implicating chi-like sequences in the meiotic recombination. Our data support the idea that the 9.4-kb BamHI allele is more productive than the 9.0 (9.2)-kb allele in normal healthy donors, possibly due to the extended switch regions, whereas duplication of the gamma4 gene has no effect on switching and IgG4 serum levels.     

A P1-based physical map of the region from D17S776 to D17S78 containing the breast cancer susceptibility gene BRCA1

BRCA1, a breast and ovarian cancer susceptibility locus, has been isolated and maps to 17q21. A physical map of the BRCA1 region which extended from the proximal boundary at D17S776 to the distal boundary at D17S78 was constructed and consists of 51 sequence tagged sites (STSs) from P1 and YAC ends, nine new short-tandem repeat (STR) polymorphic markers, and eight identified genes. The contig, which spans the estimated 2.3 Mb region, contains 29 P1s, 11 YACs, two BACs, and one cosmid. Based on key recombinants in two linked families, BRCA1 was further localized to a region bounded by D17S1321 on the proximal side and D17S1325 on the distal side. Within this estimated 600 kb region, the contig was composed completely of P1s and BACs ordered by STS-content mapping and confirmed by DNA restriction fragment fingerprinting.     

High-efficiency Q-band GaAs FET oscillator

A microstrip GaAs FET oscillator using a 75 × 0.25 ?m device has achieved an output power of 10 mW with an efficiency of 10% at 36 GHz. This oscillator was intended for local-oscillator applications at Q-band.     

Par-4 is a mediator of neuronal degeneration associated with the pathogenesis of Alzheimer disease

Prostate apoptosis response-4 (Par-4) is a protein containing both a leucine zipper and a death domain that was isolated by differential screening for genes upregulated in prostate cancer cells undergoing apoptosis. Par-4 is expressed in the nervous system, where its function is unknown. In Alzheimer disease (AD), neurons may die by apoptosis, and amyloid beta-protein (A beta) may play a role in this. We report here that Par-4 expression is increased in vulnerable neurons in AD brain and is induced in cultured neurons undergoing apoptosis. Blockade of Par-4 expression or function prevented neuronal apoptosis induced by Ab and trophic factor withdrawal. Par-4 expression was enhanced, and mitochondrial dysfunction and apoptosis exacerbated, in cells expressing presenilin-1 mutations associated with early-onset inherited AD.     

Differences in the extent of inflammation caused by intratracheal exposure to three ultrafine metals: role of free radicals

The Concorde trial compared immediate (Imm) with deferred (Def) AZT monotherapy in asymptomatic HIV-positive participants. Haematological and immunological markers and weight were measured throughout, and correlated with clinical endpoints. Markers associated with disease progression (CD4 lymphocyte count and percentage, platelets, p24 antigen and beta 2 microglobulin favoured Imm: those associated with toxicity (haemoglobin, neutrophils and white cell count) favoured Def. CD8 and total lymphocyte count did not differ significantly between groups. In multivariate analysis, the combination of baseline CD4, p24 antigen and beta 2m was the best baseline predictor of disease. Including change in CD4 and beta 2m at 12 weeks, or changes over follow-up in these markers significantly improved the fit. Markers were also incorporated into the definition of 'clinical' endpoints. Hazard ratio estimates from end-points that included CD4 < 50 and CD4 < 25 were closest to those for AIDS or death alone, but added very few extra events. Use of other landmark CD4 counts (100 or greater) or relative decreases in counts (25% or more) increased the number of events, but overestimated the effect of immediate AZT. Although AZT had a beneficial effect on the surrogate markers of efficacy evaluated, these changes did not predict clinical outcome, nor could the markers be usefully incorporated into an endpoint definition.     

Processing and properties of carbon nanotubes–nano-SiC ceramic

Carbon nanotubes–nano-SiC ceramic has been fabricated by the hot-press method. The preparation steps involved the use of dispersing nano-SiC powders and carbon nanotubes in butylalcohol using an ultrasonic shaker. The reasonable relative density of about 95% has been achieved by hot-pressing at 2273 K (at 25 MPa in Ar for 1 h). The three-point bending strength and fracture toughness of the composite has about 10% increment over monolithic SiC ceramic which was fabricated under the same process. The reasons for the increment are the strengthening and toughening role of carbon nanotubes occuring in the matrix.