Angular anisotropy of the fusion-fission and quasifission fragments

The anisotropy in the angular distribution of the fusion-fission and quasifission fragments for the $^{16}$O+$^{238}$U, $^{19}$F+$^{208}$Pb and $^{32}$S+$^{208}$Pb reactions is studied by analyzing the angular momentum distributions of the dinuclear system and compound nucleus which are formed after capture and complete fusion, respectively. The orientation angles of axial symmetry axes of colliding nuclei to the beam direction are taken into account for the calculation of the variance of the projection of the total spin onto the fission axis. It is shown that the deviation of the experimental angular anisotropy from the statistical model picture is connected with the contribution of the quasifission fragments which is dominant in the $^{32}$S+$^{208}$Pb reaction. Enhancement of anisotropy at low energies in the $^{16}$O+$^{238}$U reaction is connected with quasifission of the dinuclear system having low temperature and effective moment of inertia.Comment: 17 pages 8 figures. Submitted to Euro. Phys. Jour.

Breast imaging technology: Recent advances in imaging endogenous or transferred gene expression utilizing radionuclide technologies in living subjects - applications to breast cancer

A variety of imaging technologies is being investigated as tools for studying gene expression in living subjects. Two technologies that use radiolabeled isotopes are single photon emission computed tomography (SPECT) and positron emission tomography (PET). A relatively high sensitivity, a full quantitative tomographic capability, and the ability to extend small animal imaging assays directly into human applications characterize radionuclide approaches. Various radiolabeled probes (tracers) can be synthesized to target specific molecules present in breast cancer cells. These include antibodies or ligands to target cell surface receptors, substrates for intracellular enzymes, antisense oligodeoxynucleotide probes for targeting mRNA, probes for targeting intracellular receptors, and probes for genes transferred into the cell. We briefly discuss each of these imaging approaches and focus in detail on imaging reporter genes. In a PET reporter gene system for in vivo reporter gene imaging, the protein products of the reporter genes sequester positron emitting reporter probes. PET subsequently measures the PET reporter gene dependent sequestration of the PET reporter probe in living animals. We describe and review reporter gene approaches using the herpes simplex type 1 virus thymidine kinase and the dopamine type 2 receptor genes. Application of the reporter gene approach to animal models for breast cancer is discussed. Prospects for future applications of the transgene imaging technology in human gene therapy are also discussed. Both SPECT and PET provide unique opportunities to study animal models of breast cancer with direct application to human imaging. Continued development of new technology, probes and assays should help in the better understanding of basic breast cancer biology and in the improved management of breast cancer patients

A High-Resolution GSO-based Brain PET Camera

ABSTRACT A high-resolution GSO-based PET camera is being developed for brain imaging. The system is based upon a detector that uses Anger-logic positioning with 4 x 4 x 10 mm3 crystals coupled to a continuous light-guide and an array of 39-mm diameter photo-multiplier tubes. Measurements of a small crystal array have demonstrated that individual crystals can be resolved. The system is 3D (no septa) with a diameter of 42 cm and an axial field-of-view of 25 cm. The detector and overall scanner design has been guided by Monte Carlo simulations. The GSO PET scanner will have improved spatial resolution and higher count-rate capability than the NaI (TI) HEAD Penn-PET scanner that was built previously. GSO was chosen because of its higher stopping power, faster decay, and excellent energy resolution, which is critical for good scatter rejection

High Cooperativity of the SV40 Major Capsid Protein VP1 in Virus Assembly

SV40 is a small, non enveloped DNA virus with an icosahedral capsid of 45 nm. The outer shell is composed of pentamers of the major capsid protein, VP1, linked via their flexible carboxy-terminal arms. Its morphogenesis occurs by assembly of capsomers around the viral minichromosome. However the steps leading to the formation of mature virus are poorly understood. Intermediates of the assembly reaction could not be isolated from cells infected with wt SV40. Here we have used recombinant VP1 produced in insect cells for in vitro assembly studies around supercoiled heterologous plasmid DNA carrying a reporter gene. This strategy yields infective nanoparticles, affording a simple quantitative transduction assay. We show that VP1 assembles under physiological conditions into uniform nanoparticles of the same shape, size and CsCl density as the wild type virus. The stoichiometry is one DNA molecule per capsid. VP1 deleted in the C-arm, which is unable to assemble but can bind DNA, was inactive indicating genuine assembly rather than non-specific DNA-binding. The reaction requires host enzymatic activities, consistent with the participation of chaperones, as recently shown. Our results demonstrate dramatic cooperativity of VP1, with a Hill coefficient of ∼6. These findings suggest that assembly may be a concerted reaction. We propose that concerted assembly is facilitated by simultaneous binding of multiple capsomers to a single DNA molecule, as we have recently reported, thus increasing their local concentration. Emerging principles of SV40 assembly may help understanding assembly of other complex systems. In addition, the SV40-based nanoparticles described here are potential gene therapy vectors that combine efficient gene delivery with safety and flexibility

A CI-Independent Form of Replicative Inhibition: Turn Off of Early Replication of Bacteriophage Lambda

Several earlier studies have described an unusual exclusion phenotype exhibited by cells with plasmids carrying a portion of the replication region of phage lambda. Cells exhibiting this inhibition phenotype (IP) prevent the plating of homo-immune and hybrid hetero-immune lambdoid phages. We have attempted to define aspects of IP, and show that it is directed to repλ phages. IP was observed in cells with plasmids containing a λ DNA fragment including oop, encoding a short OOP micro RNA, and part of the lambda origin of replication, oriλ, defined by iteron sequences ITN1-4 and an adjacent high AT-rich sequence. Transcription of the intact oop sequence from its promoter, pO is required for IP, as are iterons ITN3–4, but not the high AT-rich portion of oriλ. The results suggest that IP silencing is directed to theta mode replication initiation from an infecting repλ genome, or an induced repλ prophage. Phage mutations suppressing IP, i.e., Sip, map within, or adjacent to cro or in O, or both. Our results for plasmid based IP suggest the hypothesis that there is a natural mechanism for silencing early theta-mode replication initiation, i.e. the buildup of λ genomes with oop+ oriλ+ sequence

Explaining state development: Indonesia from its pre-independence origins to contemporary democracy.

Explaining State Development: Indonesia from Pre-Independence Origins to Contemporary Democracy. This thesis uses the Indonesian case to present a new paradigm for explaining the state development of new or relatively new (post-World War II) states. The first chapter describes this paradigm of organic and mechanical types of state development, argues that the development of the Indonesian state from the 1950s to 1990s is a good example of the mechanical type of development and shows how this can be confirmed by assessing and comparing the capabilities of the four different versions of a modern state developed by Indonesia since independence. The next chapter examines Indonesia’s pre-independence debates about the form of state to be adopted, which led to Indonesia accepting a Western model of the state that has since undergone a development process involving four different versions of a ‘modern’ state. These four versions of the state are defined according to their type of regime and policymaking institutions: I) parliamentary democracy, II) Sukarno’s civilian presidential monarchy, III) Suharto’s military presidential monarchy and IV) presidential democracy. Chapters Three to Six assess and compare these four versions’ capability in three key areas: 1) achieving legal legitimacy, 2) control of the military and 3) dealing with political disorder – a crucial area of state capability that requires two chapters. Then Chapter Seven examines and explains the pre-democratic origins of the present version of the Indonesian state, the presidential democracy of Version IV. The Conclusion collates the findings of Chapters Three to Six on capabilities and summarises the arguments of Chapters Two and Seven regarding the 1940s acceptance of the Western model of the state and the late 1990s opportunity for democratisation. Finally, there is a concluding assessment of the potential of the organic/mechanical typology as a new paradigm for studying state development in other countries, regions and eras