SQUID NMR Studies of the Second Layer of 3He at High Density

Nuclear magnetism in the second layer of ³He films on graphite has been studied as a function of density in the zero-field limit at temperatures down to 300 µK. Total surface coverages in this study ranged from 20 atoms/nm² (the lowest coverage at which the effective exchange parameter turns ferromagnetic) through the two-phase region (ending at about 24 atoms/nm²) and into the single-phase imcommensurate solid region up to 31.2 atoms/nm². The surface layers were studied using both pulsed and cw NMR measured with our SQUID NMR system in magnetic fields of 500 µT and lower. As the surface density continues to increase in the single-phase region, the exchange constant decreases consistently with a picture of steric hindrance impeding ferromagnetic exchange. Several different observational features scale with this inferred exchange: low-field magnetization, NMR frequency shift, and the temperature of onset of significant magnetization.     

Inclusion body fibromatosis of the breast. Two cases with immunohistochemical and ultrastructural findings

Two cases of fibromatosis of the breast, characterized by a proliferation of spindle cells containing intracytoplasmic, spherical, eosinophilic inclusion bodies, are reported. The light and electron microscopic features, as well as the immunohistochemical features, are indistinguishable from those found in infantile digital fibromatosis. The proliferating spindle cells are characterized as myofibroblasts, whereas the inclusion bodies show an immunohistochemically nonreactive, hollow-like pattern with peripheral reactivity for actin filaments. This lesion, observed for the first time in the breast, expands the number of extradigital inclusion body fibromatoses.     

Congenic rats reveal three independent Copenhagen alleles within the Mcs1 quantitative trait locus that confer resistance to mammary cancer

It has previously been shown that the Copenhagen (COP) rat contains several genetic loci that contribute to its mammary tumor-resistant phenotype after 7,12-dimethylbenz(a)anthracene (DMBA) administration. One of these loci, mammary carcinoma susceptibility 1 (Mcs1), is located on the centromeric end of chromosome 2 and appears to act in a semidominant fashion. To confirm the existence and independent action of this locus and also aid in the identification of the physical location of the Mcs1 gene, congenic lines were generated by transferring the Mcs1 COP allele onto a Wistar Furth (WF) genetic background. Male carriers were genotyped using microsatellite markers spanning 20-30 cM of the Mcs1 locus. One of the congenic lines minimally retained the COP allele at D2Mit29 on the centromeric end of chromosome 2 and extended distally to D2Rat201. Heterozygous Mcs1 carrier rats were interbred, and the female offspring were treated with DMBA. The female rats from the Mcs1 congenic line that carried one or two COP alleles of the Mcs1 region had a significantly reduced (65 and 85%, respectively) tumor development (P < 0.001) compared with rats carrying zero COP alleles at this locus. A WF.COP-D2Mit29/D2Rat201 homozygous congenic strain derived at the N10 generation was treated with DMBA, and the COP homozygous rats developed 1.5 +/- 0.3 carcinomas/rat versus 6.3 +/- 0.5 in WF control rats (P < 0.0001). Fine mapping of this congenic interval using several recombinant lines identified three genetic loci within the Mcs1 congenic region that independently supported a tumor resistance phenotype. These genetic loci have been termed Mcs1a, Mcs1b, and Mcs1c. In rats for which each locus was homozygous for the COP allele, tumor development was reduced by approximately 60% compared with littermate controls. The identification of these independent loci within the Mcs1 COP allele provide a model of the genetic complexity of cancer.     

Single-chip design of bit-error-correcting stack decoders

The design of a single-chip VLSI system to implement the Zigangirov-Jelinek sequential decoding algorithm for bit-error-correction is described and the dependence of performance on design parameters is discussed. By virtue of being self-contained, having few input and output pins, and processing stack elements once each clock cycle, the system should be capable of high-speed decoding. For constraint length 21, rate 1/2 codes, and 3-b soft decision detection, it is found that a system containing approximately 25000 stack cells reduces errors in a 3-dB signal-to-noise level environment, corresponding to 7.8% hard decision error rate, by two orders of magnitude. Higher decoding gain is obtained at lower noise levels through the use of a relatively long constraint length. The constraint length is not limited by the architecture. Chip area estimates needed to obtain prescribed decoded error rates and average decoding rates are also described and indicate that an effective system is potentially achievable with current technology     

Calretinin-immunoreactive neurons in the human thalamus

To identify plant defense components that are important in restricting the growth of virulent pathogens, we screened for Arabidopsis mutants in the accession Columbia (carrying the transgene BGL2-GUS) that display enhanced disease susceptibility to the virulent bacterial pathogen Pseudomonas syringae pv. maculicola (Psm) ES4326. Among six (out of a total of 11 isolated) enhanced disease susceptibility (eds) mutants that were studied in detail, we identified one allele of the previously described npr1/nim1/sai1 mutation, which is affected in mounting a systemic acquired resistance response, one allele of the previously identified EDS5 gene, and four EDS genes that have not been previously described. The six eds mutants studied in detail (npr1-4, eds5-2, eds10-1, eds11-1, eds12-1, and eds13-1) displayed different patterns of enhanced susceptibility to a variety of phytopathogenic bacteria and to the obligate biotrophic fungal pathogen Erysiphe orontii, suggesting that particular EDS genes have pathogen-specific roles in conferring resistance. All six eds mutants retained the ability to mount a hypersensitive response and to restrict the growth of the avirulent strain Psm ES4326/avrRpt2. With the exception of npr1-4, the mutants were able to initiate a systemic acquired resistance (SAR) response, although enhanced growth of Psm ES4326 was still detectable in leaves of SAR-induced plants. The data presented here indicate that eds genes define a variety of components involved in limiting pathogen growth, that many additional EDS genes remain to be discovered, and that direct screens for mutants with altered susceptibility to pathogens are helpful in the dissection of complex pathogen response pathways in plants.     

Texture and hydrodynamics of a thin slab of superfluid3He-A in a torsional oscillator. II. Experiment

Experiments on a torsional oscillator containing a slab of liquid³He of thickness 105 µm and diameter 8.38 mm are described. Normal phase experiments confirm the theory of the oscillator dynamics but an apparent descrase in the measured value of T ² at lowT casts doubt on the existing slip theory. Measurements for the uniform texture for the A phase give values of _s and ₄₄. The _s measurements suggest that the A-phase energy gap is enhanced by a factor 1.24 over the BCS value. Distortion of the uniform texture by a magnetic field perpendicular to the slab occurs at a threshold field slightly smaller than predicted. Measurements for fields at different angles to the slab enable accurate values to be deduced for the superfluid density anisotropy and two other viscosity coefficients. The remaining two viscosity coefficients are only poorly determined. Flow alignment of the orbital texture was achieved by increasing the oscillator amplitude. A different texture obtained on some occasions after warming from the B phase was investigated but is not understood.     

Correction to: An Updated Index Including Toughness for Hot-Cracking Susceptibility

Metallurgical and Materials Transactions A -     

An Updated Index Including Toughness for Hot-Cracking Susceptibility

Metallurgical and Materials Transactions A - Hot cracking is one of the major defects that can occur in laser-based additive manufacturing. During the terminal stage of solidification, hot cracking...