Quasi-phase-matched high-order harmonic generation using tunable pulse trains

A simple technique for generating trains of ultrafast pulses is demonstrated in which the linear separation between pulses can be varied continuously over a wide range. These pulse trains are used to achieve tunable quasi-phase-matching of high harmonic generation over a range of harmonic orders up to the harmonic cut-off, resulting in enhancements of the harmonic intensity in excess of an order of magnitude. The peak enhancement depends on the separation between pulses, as well as the number of pulses in the train, representing an easily tunable source of quasi-phase-matched high harmonic generation

Identification of a New Rhoptry Neck Complex RON9/RON10 in the Apicomplexa Parasite Toxoplasma gondii

Apicomplexan parasites secrete and inject into the host cell the content of specialized secretory organelles called rhoptries, which take part into critical processes such as host cell invasion and modulation of the host cell immune response. The rhoptries are structurally and functionally divided into two compartments. The apical duct contains rhoptry neck (RON) proteins that are conserved in Apicomplexa and are involved in formation of the moving junction (MJ) driving parasite invasion. The posterior bulb contains rhoptry proteins (ROPs) unique to an individual genus and, once injected in the host cell act as effector proteins to co-opt host processes and modulate parasite growth and virulence. We describe here two new RON proteins of Toxoplasma gondii, RON9 and RON10, which form a high molecular mass complex. In contrast to the other RONs described to date, this complex was not detected at the MJ during invasion and therefore was not associated to the MJ complex RON2/4/5/8. Disruptions of either RON9 or RON10 gene leads to the retention of the partner in the ER followed by subsequent degradation, suggesting that the RON9/RON10 complex formation is required for proper sorting to the rhoptries. Finally, we show that the absence of RON9/RON10 has no significant impact on the morphology of rhoptry, on the invasion and growth in fibroblasts in vitro or on virulence in vivo. The conservation of RON9 and RON10 in Coccidia and Cryptosporidia suggests a specific relation with development in intestinal epithelial cells

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Order dependent spatial properties of high harmonic generation

We report on the dependence of the spatial properties of high harmonic generation on the harmonic order. We present interesting features in the transverse spatial coherence which may be important for coherent imaging experiments © OSA 2014

Order dependent spatial properties of high harmonic generation

We report on the dependence of the spatial properties of high harmonic generation on the harmonic order. We present interesting features in the transverse spatial coherence which may be important for coherent imaging experiments.Research in Optical Sciences © OSA 2014

General analytic solution for far-field phase and amplitude control, with a phase-only spatial light modulator

An analytical solution is presented for the phase which should be introduced by a phase-only spatial lightmodulator to generate far field phase and amplitude distributions within a domain of interest. The solution isdemonstrated experimentally and shown to enable excellent control of the farfield amplitude and phase

Improving the resolution obtained in lensless imaging with spatially shaped high-order harmonics

The resolution obtained with coherent diffractive imaging (CDI) is limited by a number of factors, one of which is the transverse coherence of the illuminating beam. For a successful reconstruction, it is accepted that the illuminating beam should have a lateral coherence length of at least twice the largest linear dimension of the sampl

Improving the resolution obtained in lensless imaging with spatially shaped high-order harmonics

The resolution obtained with coherent diffractive imaging (CDI) is limited by a number of factors, one of which is the transverse coherence of the illuminating beam. For a successful reconstruction, it is accepted that the illuminating beam should have a lateral coherence length of at least twice the largest linear dimension of the sampl