972 resultados para Iranian nuclear program
Resumo:
4th Annual Lincoln University Sonia Kovalevsky Math for Girls Day program on April 24, 2009.
Resumo:
9th Annual Lincoln University Sonia Kovalevsky Math for Girls Day program on April 25, 2014.
DNA Replication in Quiescent Cell Nuclei: Regulation by the Nuclear Envelope and Chromatin Structure
Resumo:
Quiescent nuclei from differentiated somatic cells can reacquire pluripotence, the capacity to replicate, and reinitiate a program of differentiation after transplantation into amphibian eggs. The replication of quiescent nuclei is recapitulated in extracts derived from activated Xenopus eggs; therefore, we have exploited this cell-free system to explore the mechanisms that regulate initiation of replication in nuclei from terminally differentiated Xenopus erythrocytes. We find that these nuclei lack many, if not all, pre-replication complex (pre-RC) proteins. Pre-RC proteins from the extract form a stable association with the chromatin of permeable nuclei, which replicate in this system, but not with the chromatin of intact nuclei, which do not replicate, even though these proteins cross an intact nuclear envelope. During extract incubation, the linker histones H1 and H10 are removed from erythrocyte chromatin by nucleoplasmin. We show that H1 removal facilitates the replication of permeable nuclei by increasing the frequency of initiation most likely by promoting the assembly of pre-RCs on chromatin. These data indicate that initiation in erythrocyte nuclei requires the acquisition of pre-RC proteins from egg extract and that pre-RC assembly requires the loss of nuclear envelope integrity and is facilitated by the removal of linker histone H1 from chromatin.
Resumo:
The proto-oncogene c-myc (myc) encodes a transcription factor (Myc) that promotes growth, proliferation and apoptosis. Myc has been suggested to induce these effects by induction/repression of downstream genes. Here we report the identification of potential Myc target genes in a human B cell line that grows and proliferates depending on conditional myc expression. Oligonucleotide microarrays were applied to identify downstream genes of Myc at the level of cytoplasmic mRNA. In addition, we identified potential Myc target genes in nuclear run-on experiments by changes in their transcription rate. The identified genes belong to gene classes whose products are involved in amino acid/protein synthesis, lipid metabolism, protein turnover/folding, nucleotide/DNA synthesis, transport, nucleolus function/RNA binding, transcription and splicing, oxidative stress and signal transduction. The identified targets support our current view that myc acts as a master gene for growth control and increases transcription of a large variety of genes.
Resumo:
The Epstein-Barr virus-encoded nuclear antigen EBNA-1 gene promoter for the restricted Epstein-Barr virus (EBV) latency program operating in group I Burkitt lymphoma (BL) cell lines was previously identified incorrectly. Here we present evidence from RACE (rapid amplification of cDNA ends) cloning, reverse transcription-PCR, and S1 nuclease analyses, which demonstrates that the EBNA-1 gene promoter in group I BL cell lines is located in the viral BamHI Q fragment, immediately upstream of two low-affinity EBNA-1 binding sites. Transcripts initiated from this promoter, referred to as Qp, have the previously reported Q/U/K exon splicing pattern. Qp is active in group I BL cell lines but not in group III BL cell lines or in EBV immortalized B-lymphoblastoid cell lines. In addition, transient transfection of Qp-driven reporter constructs into both an EBV-negative BL cell line and a group I BL cell line gave rise to correctly initiated transcripts. Inspection of Qp revealed that it is a TATA-less promoter whose architecture is similar to the promoters of housekeeping genes, suggesting that Qp may be a default promoter which ensures EBNA-1 expression in cells that cannot run the full viral latency program. Elucidation of the genetic mechanism responsible for the EBNA-1-restricted program of EBV latency is an essential step in understanding control of viral latency in EBV-associated tumors.
Resumo:
After the presidential elections on June 14th, the Iranian regime will continue its catch-me-if-you-can game with the international community until it has reached the nuclear threshold. Paradoxically, the key to a solution on the nuclear issue might just lie in discussions on a WMD-free Middle East, but only after Iran has obtained nuclear military capability. At that point, and in the context of a new arms race, both regional and international players may be persuaded that the Middle East has more to gain from negotiations on non-proliferation than from prolonged isolation and the prospect of intractable war.
Resumo:
The five permanent members of the UN Security Council (the USA, the United Kingdom, China, France and Russia) plus Germany and the European Union signed a deal with Iran on 14 July in Vienna (a Plan of Action with five appendices, henceforth referred to as the Vienna Agreement). Under this agreement, Iran undertook to restrict its nuclear programme and to bring it under international scrutiny for 15 years in exchange for a gradual lifting of international sanctions (both those imposed between 2006 and 2010 by the UN Security Council and the unilateral US and EU sanctions). Even though Russia has officially reacted positively to this deal, the consequences it will have are rather ambiguous from Moscow’s point of view. Iran looks set to become stronger and will possibly normalise its relations with the West, and especially the United States. This, in political terms, is a disadvantage for Russia. The Kremlin’s ability to use its policy towards Iran as a bargaining chip in contacts with Washington will be reduced significantly. In turn, the benefits will include improving the perception of Russia in the West and the opening up of new opportunities for the geopolitical game in the region, both with Iran and its opponents in the Arab world. Similarly, in economic terms, the possible lifting of sanctions will offer Russia new opportunities to achieve immediate benefits owing to co-operation in the nuclear and military-technical areas. In the short term, the lifting of sanctions will not pose any threat to Russia’s position on the global energy markets. However, in the long term, the end of Iran’s international isolation may bring negative consequences for Russia, such as the dominant position of Western and/or Chinese companies in the Iranian upstream sector, rising exports of Iranian oil and gas to EU and Asian markets (which are essential for Russia) and the downward pressure on oil and gas prices.
Resumo:
U.S. Atomic Energy Commission Report No. TID-3556.
Resumo:
AEC Report No. TID-3556(REV. 1).
Resumo:
"Issued April 3, 1962"
Resumo:
"Listing of reports dealing with eleven reactors of the Power Reactor Demonstration Program."
Resumo:
"October 1960 [OTI Issuance Date]."
Resumo:
"October 1967."
Resumo:
"November 7, 1960."
Resumo:
Final report, Feb. 1979.
