181 research outputs found
Initial Considerations Before Designing a Promoter Construct.
Before designing a synthetic promoter, it can be helpful to think about its final application. Is the study purely an in vitro exercise in monitoring short-term promoter activity from an episomal vector, or does the promoter eventually need to be permanently active and be integrated into the genome or perhaps even to function in vivo? The final application will have a bearing on promoter design and vector of choice from the start of the study. In this chapter I highlight some of the vector attributes to consider and features that should be thought about
High precision branching ratio measurement for the superallowed ÎČ decay of [Formula Presented] A prerequisite for exacting tests of the standard model
Nonanalog Fermi and Gamow-Teller branches in the superallowed ÎČ decay of [Formula Presented] have been investigated using Îł-ray and conversion-electron spectroscopy. Nine observed transitions, in conjunction with a recent shell model calculation, determine the branching ratio of the analog transition to be 99.5(1)%. The experimental upper limits for the Fermi decay to the [Formula Presented] and [Formula Presented] levels are in agreement with recent theoretical predictions. The [Formula Presented] value for the [Formula Presented] ÎČ decay is predicted to be 10405(9) keV. © 2003 The American Physical Society
First observation of the drip line nucleus \u3csup\u3e140\u3c/sup\u3eDy: Identification of a 7 ÎŒs K isomer populating the ground state band
A new 7 ÎŒs isomer in the drip line nucleus 140Dy was selected from the products of the 54Fe (315 MeV) + 92Mo reaction by a recoil mass spectrometer and studied with recoil-delayed Îł-Îł coincidences. Five cascading Îł transitions were interpreted as the decay of an IÏ = 8- {Îœ9/2-[514]â Îœ7/2+[404]} Kisomer (T 1/2 = 7.0(5) ÎŒs) via the ground-state band. The probability of proton emission from 141Ho to the 0+ ground state and to the 2+ excited state in 140Dy is discussed
Fine structure in proton emission
Mapping the triangle : international conference on nuclear structure, Grand Teton National Park, Wyoming 22-25 May 2002 / editors, Ani Aprahamian ... [et al.
New ÎŒs isomers in Tz=1 nuclei produced in the 112Sn(63A MeV)+natNi reaction
Expérience GANIL, équipement SISSI/LISE
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Proton Radioactivity Measurements at HRIBF: Ho, Lu, and Tm Isotopes
Two new isotopes, {sup 145}Tm and {sup 140}Ho and three isomers in previously known isotopes, {sup 141m}Ho, {sup 150m}Lu and {sup 151m}Lu have been discovered and studied via their decay by proton emission. These proton emitters were produced at the Holifield Radioactive Ion Beam Facility (HRIBF) by heavy-ion fusion-evaporation reactions, separated in A/Q with a recoil mass spectrometer (RMS), and detected in a double-sided silicon strip detector (DSSD). The decay energy and half-life was measured for each new emitter. An analysis in terms of a spherical shell model is applied to the Tm and Lu nuclei, but Ho is considerably deformed and requires a collective model interpretation
Stable S/MAR-based episomal vectors are regulated at the chromatin level
Episomal vectors assembled from defined genetic components are a promising alternative to traditional gene therapy vectors that integrate in the host genome and may cause insertional mutations. The vector pEPI-eGFP is stably retained in the episomal state in cultured mammalian cells at low copy number for many generations without integration into the host genome. Although pEPI-eGFP is a fully engineered vector, little is known about how it interacts with the host genome and about the molecular mechanisms that are responsible for its transcriptional activity. We have analyzed the expression of the episomal reporter gene eGFP under conditions that affect the chromatin state of the genome. We have also constructed pEPI derivatives carrying a tandem array of lac operator sequences, which allows in vivo visualization and manipulation of the chromatin state of the episome. We show that changes in chromatin state of both the host and pEPI-eGFP induces changes in episomal gene activity and influences the episomeâs nuclear distributions. We conclude that episomal genes are subject to control systems of the host, similarly to their counterparts in the host genome
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Proton Decay Studies of the Light Lu, Tm and Ho Isotopes
A double-sided Si-strip detector system has been installed and commissioned at the focal plane of the Recoil Mass Spectrometer at the Holifield Radioactive Ion Beam Facility. The system can be used for heavy charged particle emission studies with half-lives as low as a few {micro}sec. In this paper the authors present identification and study of the decay properties of the five new proton emitters: {sup 140}Ho, {sup 141m}Ho, {sup 145}Tm, {sup 150m}Lu and {sup 151m}Lu
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