| 1. |
|
|
| 2. |
|
|
| 3. |
- Kainu, T, et al.
(author)
-
Somatic deletions in hereditary breast cancers implicate 13q21 as a putative novel breast cancer susceptibility locus
- 2000
-
In: Proceedings of the National Academy of Sciences. - 1091-6490. ; 97:17, s. 9603-9608
-
Journal article (peer-reviewed)abstract
- A significant proportion of familial breast cancers cannot be explained by mutations in the BRCA1 or BRCA2 genes. We applied a strategy to identify predisposition loci for breast cancer by using mathematical models to identify early somatic genetic deletions in tumor tissues followed by targeted linkage analysis. Comparative genomic hybridization was used to study 61 breast tumors from 37 breast cancer families with no identified BRCA1 or BRCA2 mutations. Branching and phylogenetic tree models predicted that loss of 13q was one of the earliest genetic events in hereditary cancers. In a Swedish family with five breast cancer cases, all analyzed tumors showed distinct 13q deletions, with the minimal region of loss at 13q21-q22. Genotyping revealed segregation of a shared 13q21 germ-line haplotype in the family. Targeted linkage analysis was carried out in a set of 77 Finnish, Icelandic, and Swedish breast cancer families with no detected BRCA1 and BRCA2 mutations. A maximum parametric two-point logarithm of odds score of 2.76 was obtained for a marker at 13q21 (D13S1308, theta = 0.10). The multipoint logarithm of odds score under heterogeneity was 3.46. The results were further evaluated by simulation to assess the probability of obtaining significant evidence in favor of linkage by chance as well as to take into account the possible influence of the BRCA2 locus, located at a recombination fraction of 0.25 from the new locus. The simulation substantiated the evidence of linkage at D13S1308 (P < 0.0017). The results warrant studies of this putative breast cancer predisposition locus in other populations.
|
|
| 4. |
|
|
| 5. |
- Egilsson, T., et al.
(author)
-
Excitation properties of hydrogen-related photoluminescence in 6H-SiC
- 2000
-
In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 62:11, s. 7162-7168
-
Journal article (peer-reviewed)abstract
- We have studied the excitation properties of a well-known hydrogen-related bound exciton (H-BE) photoluminescence (PL) in 6H-SiC. In the case of the so-called primary H-BE's, photoluminescence excitation (PLE) spectroscopy reveals several excited states that have not been reported previously. In order to explain these states we propose a pseudodonor model. The primary H-BE's are thus regarded as donors where strongly localized holes serve as the positive cores. From a comparison between the PLE spectra of the three different primary H-BE's corresponding to the three inequivalent substitutional lattice sites in 6H-SiC, we attempt to distinguish between the hexagonal and cubic lattice sites. We have also investigated the dependence of the optically induced quenching of the H-BE PL on the energy of the exciting light. We observe that the quenching of the H-BE PL is only efficient when the exciting light has energy above the threshold for phonon-assisted free-exciton (FE) formation or when its energy coincides with the energy needed for resonant absorption into the H-BE states. When creating FE's, we observe different types of behavior depending on the initial conditions. We argue that our results are best explained by the existence of two configurations of the same charge state of the H defect, namely a stable one: A (giving rise to the H-BE PL), and a metastable one: B (not revealed in the PL spectrum). The recombination of excitons bound at these two configurations can give rise to the transformations A?B and B?A. The existence of the B configuration is revealed through the effect of the B?A process on the temporal changes of the H-BE PL.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Ivanov, Ivan Gueorguiev, et al.
(author)
-
Intrinsic photoconductivity of 6H-SiC and the free-exciton binding energy
- 2001
-
In: Materials Science Forum, Vols. 353-356. ; , s. 405-408
-
Conference paper (peer-reviewed)abstract
- The paper presents a study of the low-temperature photoconductivity of 6H-SiC. The photocurrent at the absorption edge is assigned to Auger recombination of excitons captured to impurities. This is shown to saturate and decrease with increasing the photon energy, so the further increase in the photocurrent, observed in the purest sample, can be attributed to free excitons created in non-bound states in the exciton continuum. Thus, the exciton binding energy can be estimated, E-bx approximate to 60 +/- 5 meV in 6H-SiC.
|
|
| 9. |
- Ivanov, I.G., et al.
(author)
-
Phonon energies at the M-point in 4H-SiC
- 1996
-
In: 23rd International Conference on the Physics of Semiconductors, vol. 1. - 9810227779 ; , s. 233-236
-
Conference paper (other academic/artistic)
|
|
| 10. |
|
|
