Erratum: Multiple band structures in Ge 68 de Lima, A. P.; Ramayya, A. V.; Hamilton, J. H. ...
Physical review. C, Nuclear physics,
5/1981, Letnik:
23, Številka:
5
Journal Article
The production of high-energy photons in an intermediate energy heavy-ion reaction (65 MeV/nucleon {sup 40}Ar+{sup 93}Nb) is studied by characterizing the events, which produce the photons, by the ...forward and backward, light and heavy, charged particle production. While the absolute yield of high-energy photons increases with increasing charged particle multiplicity, the spectral shape is found to be almost independent of multiplicity. This indicates that the fundamental photon production mechanism is insensitive to the impact parameter but that the production process is more probable for the more violent collisions. This is expected for an incoherent nucleon-nucleon bremsstrahlung mechanism but not for a statistical mechanism. This work also provides a comparison of two observables that have been suggested as impact parameter selectors: the high-energy photon yield and the charged particle multiplicity. We find that the photon yield, binned by particle multiplicity, does not scale as would be expected if both techniques truly measured the impact parameter. This observation can be explained by large fluctuations in the particle multiplicity at fixed impact parameter.
We have performed experiments which indicate that online monitoring of proton radiotherapy beams in tissue is feasible. Using a two-dimensional array of on-line BGO detectors, it is possible to image ...the production of /spl beta//sup +/-emitting isotopes (mainly /sup 11/C, /sup 13/N, and /sup 15/O) as a function of tissue depth and time with pulsed proton beams of sufficiently low current. These measurements allow the dose and range of charged particle radiotherapy beams to be measured directly while the treatment is being delivered.< >
Preliminary experiments have been performed which indicate that online localization of proton radiotherapy beams in tissue is feasible. Using a two-dimensional array of online sodium iodide (NaI) ...detectors it is possible to perform real-time monitoring of the production of positron emitting isotopes (mainly /sup 11/C, /sup 13/N, and /sup 15/O) as a function of depth with pulsed proton beams of sufficiently low current. A commercial PET (positron emission tomography) scanner was used off-line to verify range and activity measurements. Results of range measurements using the two techniques are in good agreement with the calculated range, to within their respective resolutions.< >
Rheumatoid arthritis (RA) is associated with the HLA-DR4 cellular subtypes Dw4 and Dw14 in Caucasians, with Dw15 in Japanese, and possibly with HLA-DR1 in Israeli Jews. Sequencing studies in ...Caucasians have shown that these molecules share a common amino acid sequence in the third hypervariable region of the DR molecule (AA 67-74: LLEQRRAA or LLEQKRAA), suggesting that this sequence is primarily associated with RA. An important argument in favor of this shared-epitope hypothesis has been the reported association between DR1 and RA in Israeli Jews. However, a later report did not confirm this association, and cellular typing showed that Israeli DR1 consists of three or more subtypes, suggesting that new subtypes might be present. Since no sequencing data on Israeli HLA-DR1 genes have been reported, we sequenced the first domain (AA 10-91) of the DRB1 gene in 12 DR1-positive Israeli RA patients, 5 healthy controls and a homozygous typing cell (HTC), defining the major Jewish cellular HLA-DR1 subtype. DRB1*0102 (DR1 Dw20) was found in 8 RA patients, 3 controls and the HTC "LVA". DRB1*0101 (DR1 Dw1) was found in 4 RA patients and 2 controls. No other DR1 subtypes were encountered. In all 20 DR1 haplotypes, the DRB1*0101 or 0102 allele was associated with DQA1*0101 and DQB1*0501, being identical to the Caucasian DR1 haplotypes. Thus, at the sequence level, we found no basis for the reported extensive cellular heterogeneity of DR1 in the Israeli population.
