| 1. |
- Amann, F., et al.
(författare)
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A search for murarregamma at the level of 10-13
- 1991
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Ingår i: Proceedings of the 25th International Conference on High Energy Physics. - 9810024347 ; , s. 1070-1071
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Konferensbidrag (refereegranskat)abstract
- The MEGA experiment, which is a search for the decay murarregamma with a branching ratio sensitivity of about 10-13, employs highly modular, fast detectors, state-of-the-art electronics, and a staged trigger with on-line filters. The detectors are contained in a 1.5-T solenoidal field produced by a superconducting magnet. Positrons are confined to the central region and are measured by a set of thin MWPCs. Photons are measured by one of four layers of pair spectrometers in the outer region. Most aspects of the design have been validated in engineering runs; data taking will begin in 1990 with much of the electron arm and one pair spectrometer layer installed.
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| 2. |
- Szymanski, J. J., et al.
(författare)
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MEGA : A search for the decay mu –> e gamma
- 1994
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Ingår i: Intersections between particle and nuclear physics. Proceedings, 5th Conference, St. Petersburg, USA, May 31-June 6, 1994. ; , s. 789-792
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Konferensbidrag (refereegranskat)
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| 3. |
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| 4. |
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| 5. |
- Egholm, M., et al.
(författare)
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PNA HYBRIDIZES TO COMPLEMENTARY OLIGONUCLEOTIDES OBEYING THE WATSON-CRICK HYDROGEN-BONDING RULES
- 1993
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 365:6446, s. 566-568
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Tidskriftsartikel (refereegranskat)abstract
- DNA ANALOGUES are currently being intensely investigated owing to their potential as gene-targeted drugs1-3. Furthermore, their properties and interaction with DNA and RNA could provide a better understanding of the structural features of natural DNA that determine its unique chemical, biological and genetic properties3,4. We recently designed a DNA analogue, PNA, in which the backbone is structurally homomorphous with the deoxyribose backbone and consists of N-(2-aminoethyl)glycine units to which the nucleobases are attached5-9. We showed that PNA oligomers containing solely thymine and cytosine can hybridize to complementary oligonucleotides, presumably by forming Watson-Crick-Hoogsteen (PNA)2-DNA triplexes, which are much more stable than the corresponding DNA-DNA duplexes5-7, and bind to double-stranded DNA by strand displacement5,8. We report here that PNA containing all four natural nucleobases hybridizes to complementary oligonucleotides obeying the Watson-Crick base-pairing rules, and thus is a true DNA mimic in terms of base-pair recognition.
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| 6. |
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| 7. |
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| 8. |
- Kim, Seog K., et al.
(författare)
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RIGHT-HANDED TRIPLEX FORMED BETWEEN PEPTIDE NUCLEIC-ACID PNA-T(8) AND POLY(DA) SHOWN BY LINEAR AND CIRCULAR-DICHROISM SPECTROSCOPY
- 1993
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 115:15, s. 6477-6481
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Tidskriftsartikel (refereegranskat)abstract
- The binding of an eightmer of peptide nucleic acid, H-T8-Lys-NH2 (=PNA-T8), to a polynucleotide, poly(dA), was studied by flow linear dichroism (LD) and circular dichroism (CD) spectroscopy. Whereas the single stranded DNA, due to its high flexibility, does not display any measurable LD signal when subjected to shear flow, the complex with PNA does. A titration shows that saturation occurs at a stoichiometry of two PNA thymine bases per DNA adenine base, indicating the formation of a triplex PNA2-DNA complex. The persistence length of the adduct remains small up to relatively high stoichiometries (above 1:1 T:A) indicating that no significant amounts of PNA:DNA duplex are formed. Instead triplex stretches seem to form surrounded by flexible parts of single stranded poly(dA). Upon approaching the stoichiometry 2:1 of T:A the LD increases dramatically demonstrating that the stiffness of the PNA-DNA triplex arises from base-base contacts preventing bending of the chain. It is also inferred that the main stiffness of duplex DNA very probably has a similar origin and is not primarily a result of the increased phosphate-phosphate repulsion. Circular dichroism spectra support the conclusion that a triplex is formed as the only PNA-DNA complex and that it is a right-handed helix. The wavelength dependence of the reduced linear dichroism shows that the inclination of the bases from perpendicularity relative to the helix axis is small. The base conformation of the poly(dA)[PNA-T8]2 triplex is very similar to that of the conventional poly(dA)[poly(dT)]2 triplex.
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| 9. |
- Kim, Y J, et al.
(författare)
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A multiprotein mediator of transcriptional activation and its interaction with the C-terminal repeat domain of RNA polymerase II.
- 1994
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Ingår i: Cell. - 0092-8674 .- 1097-4172. ; 77:4, s. 599-608
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Tidskriftsartikel (refereegranskat)abstract
- A mediator was isolated from yeast that enabled a response to the activator proteins GAL4-VP16 and GCN4 in a transcription system reconstituted with essentially homogeneous basal factors and RNA polymerase II. The mediator comprised some 20 polypeptides, including the three subunits of TFIIF and other polypeptides cross-reactive with antisera against GAL11, SUG1, SRB2, SRB4, SRB5, and SRB6 proteins. Mediator not only enabled activated transcription but also conferred 8-fold greater activity in basal transcription and 12-fold greater efficiency of phosphorylation of RNA polymerase II by the TFIIH-associated C-terminal repeat domain (CTD) kinase, indicative of mediator-CTD interaction. A holoenzyme form of RNA polymerase II was independently isolated that supported a response to activator proteins with purified basal factors. The holoenzyme proved to consist of mediator associated with core 12-subunit RNA polymerase II.
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| 10. |
- Kröll, Stefan, et al.
(författare)
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Intensity dependent photon echo relaxation in rare earth doped crystals
- 1990
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Ingår i: Physical Review B (Condensed Matter). - 0163-1829. ; 41:16, s. 11568-11571
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Tidskriftsartikel (refereegranskat)abstract
- Photon-echo-relaxation measurements made on the 3H4-3P0 transition of 0.01 at. % Pr3+:YAG (where YAG represents yttrium aluminum garnet), 3H4-1D2 transition in 0.1 at. % Pr3+:YAlO3, and 7F0-5D0 transition in 0.25 at. % Eu3+:YAlO3 show that the photon-echo relaxation rate increases when the intensities of the excitation pulses are increased. Although a part of the relaxation-rate increase in Pr3+:YAG may be attributed to an instantaneous spectral diffusion (ISD) in which the presence of excited neighboring Pr3+ ions change the local field and the absorption frequency of the rare-earth ions, our data deviate significantly from the ISD-model predictions. An additional intensity-dependent relaxation mechanism is required to explain the results.
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