An increase in N-Ras expression is associated with development of hormone refractory prostate cancer in a subset of patients

Protein expression of H, K and N-Ras was assessed in hormone sensitive and hormone refractory prostate tumour pairs from 61 patients by immunohistochemistry. Expression of H-Ras and K- Ras was not associated with any known clinical parameters. In contrast an increase in N-Ras membrane expression in the transition from hormone sensitive to hormone refractory prostate cancer was associated with shorter time to relapse (p=0.01) and shorter disease specific survival (p=0.008). In addition, patients with an increase in N-Ras membrane expression had lower levels of PSA at relapse (p=0.02) and expression correlated with phosphorylated MAP kinase (p=0.010) and proliferation index (Ki67, p=0.02). These results suggest that in a subgroup patients N-Ras expression is associated with development of hormone refractory prostate cancer via activation of the MAP kinase cascade

Running a distributed virtual observatory: US Virtual Astronomical Observatory operations

Operation of the US Virtual Astronomical Observatory shares some issues with modern physical observatories, e.g., intimidating data volumes and rapid technological change, and must also address unique concerns like the lack of direct control of the underlying and scattered data resources, and the distributed nature of the observatory itself. In this paper we discuss how the VAO has addressed these challenges to provide the astronomical community with a coherent set of science-enabling tools and services. The distributed nature of our virtual observatory-with data and personnel spanning geographic, institutional and regime boundaries-is simultaneously a major operational headache and the primary science motivation for the VAO. Most astronomy today uses data from many resources. Facilitation of matching heterogeneous datasets is a fundamental reason for the virtual observatory. Key aspects of our approach include continuous monitoring and validation of VAO and VO services and the datasets provided by the community, monitoring of user requests to optimize access, caching for large datasets, and providing distributed storage services that allow user to collect results near large data repositories. Some elements are now fully implemented, while others are planned for subsequent years. The distributed nature of the VAO requires careful attention to what can be a straightforward operation at a conventional observatory, e.g., the organization of the web site or the collection and combined analysis of logs. Many of these strategies use and extend protocols developed by the international virtual observatory community.Comment: 7 pages with 2 figures included within PD

Surface excitonic emission and quenching effects in ZnO nanowire/nanowall systems: limiting effects on device potential.

We report ZnO nanowire/nanowall growth using a two-step vapour phase transport method on a-plane sapphire. X-ray diffraction and scanning electron microscopy data establish that the nanostructures are vertically well-aligned with c-axis normal to the substrate, and have a very low rocking curve width. Photoluminescence data at low temperatures demonstrate the exceptionally high optical quality of these structures, with intense emission and narrow bound exciton linewidths. We observe a high energy excitonic emission at low temperatures close to the band-edge which we assign to the surface exciton in ZnO at ~ 3.366 eV, the first time this feature has been reported in ZnO nanorod systems. This assignment is consistent with the large surface to volume ratio of the nanowire systems and indicates that this large ratio has a significant effect on the luminescence even at low temperatures. The band-edge intensity decays rapidly with increasing temperature compared to bulk single crystal material, indicating a strong temperature-activated non-radiative mechanism peculiar to the nanostructures. No evidence is seen of the free exciton emission due to exciton delocalisation in the nanostructures with increased temperature, unlike the behaviour in bulk material. The use of such nanostructures in room temperature optoelectronic devices appears to be dependent on the control or elimination of such surface effects

Nonlinear optical mechanism of forming periodical nanostructures in large bandgap dielectrics

Nonlinear excitation mechanisms of plasmons and their influence on femtosecond-laser induced sub-wavelength ripple generation on dielectric and semiconducting transparent materials are discussed. The agreement of theoretical and experimental data indicates the relevance of the model

Gaps and forks in DNA replication: Rediscovering old models

Most current models for replication past damaged lesions envisage that translesion synthesis occurs at the replication fork. However older models suggested that gaps were left opposite lesions to allow the replication fork to proceed, and these gaps were subsequently sealed behind the replication fork. Two recent articles lend support to the idea that bypass of the damage occurs behind the fork. In the first paper, electron micrographs of DNA replicated in UV-irradiated yeast cells show regions of single-stranded DNA both at the replication forks and behind the fork, the latter being consistent with the presence of gaps in the daughter-strands opposite lesions. The second paper describes an in vitro DNA replication system reconstituted from purified bacterial proteins. Repriming of synthesis downstream from a blocked fork occurred not only on the lagging strand as expected, but also on the leading strand, demonstrating that contrary to widely accepted beliefs, leading strand synthesis does not need to be continuous

Serial Monodomy in the Gypsy Ant, Aphaenogaster araneoides: Does Nest Odor Reduction Influence Colony Relocation?

Serial monodomy is the nesting behavior in which a colony of animals maintains multiple nests for its exclusive use, occupying one nest at a time. Among serially monodomous ants, the availability of unoccupied nests reduces the probability and costs of army ant attacks. It has been proposed that nest odors mediate serial monodomy in the gypsy ant, Aphaenogaster araneoides Emery (Hymenoptera: Formicidae), and that colonies avoid returning to previously occupied nests that harbor colony odors. To evaluate this hypothesis, the odors inside the nests of A. araneoides colonies were experimentally reduced through ventilation; the nest movement behaviors of treatment and control colonies were compared. Odor reduction was found to have increased the frequency of movements into and out of the treated nest, without a change in the total occupation duration in the treated nest. Nests with a more open architecture that permitted natural flow of air were reoccupied more quickly than nests with smaller nest entrances. In summary, the openness of the architecture of A. araneoides nests and the ventilation of air through nests alters the use of these nests. These findings further support the working hypothesis that nest-bound odors mediate the pattern of serial monodomy in A. araneoides

Characterization of microwave absorption in carbon nanotubes using resonance aperture transmission method

A new method to characterize microwave electromagnetic absorption of a bulk carbon nanotube material is proposed and experimentally evaluated in this paper. The method is based on the measurement of microwave transmission through a capacitive-resonator aperture in a conductive screen loaded with a CNT sample under test. This method allows to measure microwave permittivity and absorption of thin samples, several atomic layers to few micrometers thick, with linear dimensions much smaller than the wavelength of radiation in free space. This minimal sample requirement restricts the application of conventional microwave characterization methods such as free-space or waveguide permittivity characterization. It is demonstrated that the resonance E-field enhancement inside the CRA leads to strong EM interaction of the microwave E-field with the CNT sample under test thus enabling high sensitivity and dynamic range of the measurement procedure. Another advantage of the proposed technique over conventional non-resonance characterization methods is that in the resonance transmission band, the CRA operation is reflection-less which leads to a relatively simple qualitative algebraic de-embedding procedure of the material parameters based on the principle of energy conservation. The experimental microwave absorption data of the multiwall CNT samples are presented in the S frequency band (2-4GHz), demonstrating microwave absorption properties of the multiwall CNT ribbons

Women’s experiences of maternity care in England: preliminary development of a standard measure

Background: As maternity services evolve and the population of women served also changes, there is a continuing need to effectively document the views of women with recent experience of care. A woman's maternity experience can have a positive or negative effect upon her emotional well-being and health, in the immediate and the long-term, which can also impact the infant and the wider family system. Measuring women's perceptions of maternity services is an important way of monitoring the quality of care provision, as well as providing key indicators to organisations of the services that they are providing. It follows that, without information identifying possible areas in need of improvement, it is not clear what changes should be made to improve the experiences of women during their journey through maternity services from pregnancy to the early weeks at home with a new baby. The objective is to describe the development process and psychometric properties of a measure of women's experience of maternity care covering the three distinctly different phases of maternity - pregnancy, labour and birth, and the early postnatal period. Methods: Data from a national survey of women who had recently given birth (n = 504) were used. Exploratory and confirmatory factor analytic methods were employed. The measure was assessed for underlying latent factor structure, as well as for reliability, internal consistency, and validity (predictive, convergent and discriminant). Results: The models developed confirmed the use of three separate, but related scales about experience of maternity care during pregnancy, labour and birth and the postnatal period. Data reduction was effective, resulting in a measure with 36 items (12 per scale). Conclusion: The need for a psychometrically robust and qualitatively comprehensive measure of women's experience of maternity care has been addressed in the development and validation of this prototype measure. The whole measure can be used at one time point, or the three separate subscales used as individual measures of experience during particular phases of the maternity journey with identified factor structures in their own right