| 1. |
- Wang, Y, et al.
(author)
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Functional homology between N-myc and c-myc in murine plasmacytomagenesis : plasmacytoma development in N-myc transgenic mice
- 1992
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In: Oncogene. - 0950-9232. ; 7:6, s. 7-1241
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Journal article (peer-reviewed)abstract
- Mouse plasmacytomas induced by pristane oil alone, or in combination with Abelson murine leukemia virus (A-MuLV), regularly carry one of three alternative chromosomal translocations that juxtapose c-myc to immunoglobulin heavy- or light-chain loci. E mu-c-myc transgenic mice develop translocation-free plasmacytomas after induction by pristane oil and/or A-MuLV [Sugiyama, H., Silva, S., Wang, Y., Weber, G., Babonits, M., Rosen, A., Wiener, F. & Klein, G. (1990). Int. J. Cancer, 46, 845-852]. In order to test whether another member of the myc family, N-myc, could play a similar role as c-myc, we treated E mu-N-myc transgenic mice with pristane and helper-free A-MuLV. Of 20 mice that received a single pristane injection followed by A-MuLV, 17 developed plasmacytomas with a mean latency period of 54 +/- 20 days. In a corresponding group that only received a single pristane injection, five out of six transgenic mice developed plasmacytomas with a mean latency period of 142 +/- 32 days. However, after three monthly injections of pristane, all 15 transgenic mice developed plasmacytomas with a mean latency period of 128 +/- 20 days. All plasmacytomas expressed the N-myc transgene, while none of them expressed either c-myc or endogenous N-myc. None of the tumors carried the usual plasmacytoma-associated translocations.
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| 2. |
- Cederwall, Bo, et al.
(author)
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NEW OBLATE BAND IN HG-196 WITH QUENCHED M1 STRENGTH
- 1993
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In: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 47:6, s. R2443-R2446
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Journal article (peer-reviewed)abstract
- High-spin states in the nucleUs Hg-196 were populated in the reaction (Os(Be,5n))-Os-192 at a beam energy of 65 MeV. A regular rotational-like DELTAI = 1 band has been observed up to an excitation energy of E* almost-equal-to 8.7 MeV and spin I almost-equal-to 30hBAR. This is the second observation of a band of this character in a mercury isotope. The experimental results are compared with mean field calculations and semiclassical estimates based on the Donau-Frauendorf formalism. The mercury bands show significantly lower B(M1)/B(E2) branching ratios as compared with similar bands in light lead nuclei. This difference may be more readily explained by a difference in single-particle structure rather than by large differences in deformation between the lead and mercury configurations.
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| 3. |
- Dudman, N. P. B., et al.
(author)
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Disordered methionine/homocysteine metabolism in premature vascular disease. Its occurrence, cofactor therapy, and enzymology
- 1993
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In: Arteriosclerosis, Thrombosis and Vascular Biology. - : American Heart Association. - 1079-5642 .- 1524-4636. ; 13:9, s. 1253-1260
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Journal article (peer-reviewed)abstract
- Mild homocysteinemia occurs surprisingly often in patients with premature vascular disease. We studied the possible enzymatic sources of this mild hyperhomocysteinemia and the control of homocysteine levels in plasma by treatment of patients with the cofactors and cosubstrates of homocysteine catabolism. We assessed homocysteine metabolism in 131 patients who had premature disease in their coronary, peripheral, or cerebrovascular circulation by using a standard oral methionine-load test. Impaired homocysteine metabolism occurred in 28 patients. We assayed levels of the primary enzymes of homocysteine catabolism in cultured skin fibroblast extracts from 15 of these 28 patients. The patients' cystathionine beta-synthase levels (3.68 +/- 2.52 nmol/h per milligram of cell protein, mean +/- SD) were markedly depressed compared with those from 31 healthy adult control subjects (7.61 +/- 4.49, P < .001). The patients' levels of 5-methyltetrahydrofolate: homocysteine methyltransferase were normal. While betaine: homocysteine methyltransferase was not expressed in skin fibroblasts, 24-hour urinary betaine and N,N-dimethylglycine measurements were consistent with normal or enhanced remethylation of homocysteine by betaine: homocysteine methyltransferase in the 13 patients tested. When treated daily with choline and betaine, pyridoxine, or folic acid, there was a normalization of the postmethionine plasma homocysteine level in 16 of 19 patients. Our results indicate that mild homocysteinemia in premature vascular disease may be caused by either a folate deficiency or deficiencies in cystathionine beta-synthase activity. It does not necessarily involve deficiencies of either 5-methyltetrahydrofolate:homocysteine methyltransferase or betaine:homocysteine methyltransferase. Effective treatment regimens are also defined.
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| 4. |
- Imreh, S, et al.
(author)
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Hypersomy of chromosome 15 with retrovirally rearranged c-myc, loss of germline c-myc and IgK/c-myc juxtaposition in a macrophage-monocytic tumour line
- 1994
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In: European Journal of Cancer. - 0959-8049. ; 30A:7, s. 994-1002
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Journal article (peer-reviewed)abstract
- From a lymphoid tumour induced by 7,12-dimethylbenz-[a]-anthracene (DMBA) + methyl-N-nitrose-N-urea (MNU) in an [AKR Rb(6.15) x CBAT6T6]F1 mouse, a macrophage- monocyte line (KT-10) was isolated. Following ethyl methanesulfonate (EMS) treatment, a bromodeoxyuridine (BUdR) resistant subline was selected. Serial propagation of this line in vitro in the presence of BUdR (28 months) with periodic cytogenetic and molecular examinations, has led to the definition of four successive stages. During stage I, the cells were trisomic for chromosome 15. They contained Rb(6.15) and Rb(del6.15) of AKR and T(14;15) of CBA origin. Southern blotting showed the presence of both germline (G) and rearranged (R) c-myc. At stage II, Rb(del6.15) has duplicated. Both Rb(6.15) and T(14;15) persisted together with G-myc and R-myc. In stage III, the CBA-derived T(14;15) was lost, in parallel with G-myc. At this stage, a Dic.In(6.15) was detected. One of its arms was cytogenetically identical with the long arm of In(6.15) in the variant IgK/myc translocations. This chromosome carried R-myc and IgK in juxtaposition, as indicated by comigration on pulsed field electrophoresis (PFGE). At stage IV, the R-myc carrying AKR-derived chromosome 15s were present in six copies. Possible relationships between the increasing R/G myc ratio and changed growth characteristics in vivo and in vitro are discussed.
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| 5. |
- Linnarsson, Margareta K., et al.
(author)
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Sputter profiling of AlGaAs/GaAs superlattice structures using oxygen and argon ions
- 1993
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In: Applied Surface Science. - 0169-4332 .- 1873-5584. ; 70-71:1, s. 40-43
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Journal article (peer-reviewed)abstract
- Broadening of Al sputter profiles in AlxGa1-xAs/GaAs structures has been investigated using secondary ion mass spectrometry. The depth profiling was carried out with 32O+2 ions and 40Ar+ ions using net primary energies of 1.8, 2.2, 3.2 and 5.7 keV. The decay lengths of the Al profiles show a pronounced increase with increasing sputtering ion energy caused by ballistic mixing. Moreover, in the O+2 case the λ-values degrade with eroded depth, indicating that beam-induced surface roughening takes place during profiling and in particular, this holds for high x-values. The results are discussed in terms of a semi-empirical model for ion-beam-induced broadening developed by Zalm and Vriezema.
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| 6. |
- Ye, F.M., et al.
(author)
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Turbine governing and surge-tank stability
- 1992
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In: Journal of Hydraulic Research. - 0022-1686 .- 1814-2079. ; 30:1
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Journal article (peer-reviewed)abstract
- The stability of water-surface oscillations is investigated for the case of a tailrace surge chamber shared by two or more generating units in a hydroelectric power plant. Two kinds of turbine governing are applied for the condition of small-amplitude surge perturbations. Critical stability conditions for the surge chamber are derived by linearizing the ordinary differential equations describing the lumped system. As compared with the result achieved by previous researchers, the common surge chamber requires smaller horizontal crosssection for surge stability. A combination of the proposed manners of governing can be utilized in certain power plants in order to achieve an economical design of the surge chambers.
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