Unusual DNA binding modes for metal anticancer complexes

DNA is believed to be the primary target for many metal-based drugs. For example, platinum-based anticancer drugs can form specific lesions on DNA that induce apoptosis. New platinum drugs can be designed that have novel modes of interaction with DNA, such as the trinuclear platinum complex BBR3464. Also it is possible to design inert platinum(IV) pro-drugs which are non-toxic in the dark, but lethal when irradiated with certain wavelengths of light. This gives rise to novel DNA lesions which are not as readily repaired as those induced by cisplatin, and provides the basis for a new type of photoactivated chemotherapy. Finally, newly emerging ruthenium(II) organometallic complexes not only bind to DNA coordinatively, but also by H-bonding and hydrophobic interactions triggered by the introduction of extended arene rings into their versatile structures. Intriguingly osmium (the heavier congener of ruthenium) reacts differently with DNA but can also give rise to highly cytotoxic organometallic complexes

An aircraft borne dust particle counter and its applications to the study of clear air turbulence

Airborne photoelectric particle counter for mapping clear air turbulenc

Electronic doctoral theses in the UK: a sector-wide survey into policies, practice and barriers to Open Access

Sharing knowledge and research outputs is critical to the progress of science and human development, and a central tenet of academia. The Internet itself is a product of the academic community, and opening access to that community’s most important body of research, doctoral theses, is both a logical and an inevitable development. Progress toward open access to electronic theses has been slow in the UK. Much has been written on the perceived barriers and practical/infrastructural considerations that might explain this, but a comprehensive picture of that progress, and obstacles to it, was lacking. In 2010, a survey of policy and practice in UK HEIs was conducted by UCL (University College London) Library Services (commissioned by the Joint Information Systems Committee, JISC) to address this very issue. Incorporating inputs from 144 institutions currently awarding doctoral degrees, the work provides the first clear and detailed picture of the status of open access to doctoral research in the UK. The mission of the UK Council for Graduate Education (UKCGE) is to promote and support the interests of graduate education, and this it does through dissemination of best practice and intelligence on emergent trends; helping to shape policy and practice for the benefit of the UK HEI sector. This report contributes to that mission by bringing to the membership’s attention the results of this important work by UCL Library Services; a collaboration between UKCGE and the authors of the original work, it sets out the policies and practices that emerged from the survey and also considers what has been learned about the perceived barriers to the implementation of open access to electronic theses. The 2010 survey has enabled, for the first time, a differentiation to be made between barriers that are “real” and those which are unfounded and/or yet to be properly validated. At the same time, the work highlights the progress made in certain critical areas, as well as those that require our greater attention. A positive picture emerges for the UK on the adoption of the electronic thesis, with the majority of HEIs surveyed expected to be providing open access to their theses in five years’ time. A more detailed picture also emerges regarding the primary reasons for requests to restrict access to theses, some of which, notably, apply only to electronic (not print) theses. This has necessarily given rise to new policy developments. There is positive evidence also of collaboration among HEIs to provide an efficient and robust service for accessing electronic theses; pooling their resources and expertise either in the development of their institutional repositories or in operating a joint service. The key driver of open access to electronic theses is the opportunity for UK HEIs to “showcase” their research outputs to the widest possible audience and enhance their impact. There are no reliable means as yet to measure this impact, but there are encouraging early indications that electronic doctoral theses attract significant attention when made openly accessible. Open access to electronic theses may therefore indeed accelerate the sharing of knowledge and the progress of scientific discovery and human development

Probing the cool ISM in galaxies via 21cm HI absorption

Recent targeted studies of associated HI absorption in radio galaxies are starting to map out the location, and potential cosmological evolution, of the cold gas in the host galaxies of Active Galactic Nuclei (AGN). The observed 21 cm absorption profiles often show two distinct spectral-line components: narrow, deep lines arising from cold gas in the extended disc of the galaxy, and broad, shallow lines from cold gas close to the AGN (e.g. Morganti et al. 2011). Here, we present results from a targeted search for associated HI absorption in the youngest and most recently-triggered radio AGN in the local universe (Allison et al. 2012b). So far, by using the recently commissioned Australia Telescope Compact Array Broadband Backend (CABB; Wilson et al. 2011), we have detected two new absorbers and one previously-known system. While two of these show both a broad, shallow component and a narrow, deep component (see Fig. 1), one of the new detections has only a single broad, shallow component. Interestingly, the host galaxies of the first two detections are classified as gas-rich spirals, while the latter is an early-type galaxy. These detections were obtained using a spectral-line finding method, based on Bayesian inference, developed for future large-scale absorption surveys (Allison et al. 2012a).Comment: 1 page, 1 figure, published in Proceedings of IAU Symposium No. 29

Kinetic Monte Carlo simulations of the growth of polymer crystals

Based upon kinetic Monte Carlo simulations of crystallization in a simple polymer model we present a new picture of the mechanism by which the thickness of lamellar polymer crystals is constrained to a value close to the minimum thermodynamically stable thickness, l_{min}. The free energetic costs of the polymer extending beyond the edges of the previous crystalline layer and of a stem being shorter than l_{min} provide upper and lower constraints on the length of stems in a new layer. Their combined effect is to cause the crystal thickness to converge dynamically to a value close to l_{min} where growth with constant thickness then occurs. This description contrasts with those given by the two dominant theoretical approaches. However, at small supercoolings the rounding of the crystal profile does inhibit growth as suggested in Sadler and Gilmer's entropic barrier model.Comment: 12 pages, 13 figures, revte

HI in four star-forming low-luminosity E/S0 and S0 galaxies

We present HI data cubes of four low-luminosity early-type galaxies which are currently forming stars. These galaxies have absolute magnitudes in the range M_B=-17.9 to -19.9 (H_o=50 km/s/Mpc). Their HI masses range between a few times 10^8 and a few times 10^9 M_sun and the corresponding values for M_HI/L_B are between 0.07 and 0.42, so these systems are HI rich for their morphological type. In all four galaxies, the HI is strongly centrally concentrated with high central HI surface densities, in contrast to what is typically observed in more luminous early-type galaxies. In two galaxies (NGC 802 and ESO 118-G34), the kinematics of the HI suggests that the gas is in a strongly warped disk, which we take as evidence for recent accretion of HI. In the other two galaxies (NGC 2328 and ESO 027-G21) the HI must have been part of the systems for a considerable time. The HI properties of low-luminosity early-type galaxies appear to be systematically different from those of many more luminous early-type galaxies, and we suggest that these differences are due to a different evolution of the two classes. The star formation history of these galaxies remains unclear. Their UBV colours and Halpha emission-line strengths are consistent with having formed stars at a slowly-declining rate for most of the past 10^10 years. However, the current data do not rule out a small burst of recent star formation overlaid on an older stellar population.Comment: To appear in AJ, LateX, figures in gif format, paper also available at http://www.nfra.nl/~morganti/LowLu

Coherence-enhanced imaging of a degenerate Bose gas

We present coherence-enhanced imaging, an in situ technique that uses Raman superradiance to probe the spatial coherence properties of an ultracold gas. Applying this method, we obtain a spatially resolved measurement of the condensate number and more generally, of the first-order spatial correlation function in a gas of $^{87}$Rb atoms. We observe the enhanced decay of propagating spin gratings in high density regions of a Bose condensate, a decay we ascribe to collective, non-linear atom-atom scattering. Further, we directly observe spatial inhomogeneities that arise generally in the course of extended sample superradiance.Comment: 4 pages, 4 figure