Double-period zero-order metal gratings as effective selective absorbers

W.-C. Tan, J. Roy Sambles, and T. W. Preist, Physical Review B, Vol. 61, pp. 13177-13182 (2000). "Copyright © 2000 by the American Physical Society."The electromagnetic response of a zero-order metal grating having a primary deep short-period component and a shallow long-period component is modeled. It is found that such a metal grating has an unusual surface-plasmon-polariton band structure and exhibits strong selective absorption of incident radiation. This opens up potential for designing metal surfaces with specific optical response features

VHEE FLASH sparing effect measured at CLEAR, CERN with DNA damage of pBR322 plasmid as a biological endpoint

Ultra-high dose rate (UHDR) irradiation has been shown to have a sparing effect on healthy tissue, an effect known as ‘FLASH’. This effect has been studied across several radiation modalities, including photons, protons and clinical energy electrons, however, very little data is available for the effect of FLASH with Very High Energy Electrons (VHEE). pBR322 plasmid DNA was used as a biological model to measure DNA damage in response to Very High Energy Electron (VHEE) irradiation at conventional (0.08 Gy/s), intermediate (96 Gy/s) and ultra-high dose rates (UHDR, (2 × 109 Gy/s) at the CERN Linear Electron Accelerator (CLEAR) user facility. UHDRs were used to determine if the biological FLASH effect could be measured in the plasmid model, within a hydroxyl scavenging environment. Two different concentrations of the hydroxyl radical scavenger Tris were used in the plasmid environment to alter the proportions of indirect damage, and to replicate a cellular scavenging capacity. Indirect damage refers to the interaction of ionising radiation with molecules and species to generate reactive species which can then attack DNA. UHDR irradiated plasmid was shown to have significantly reduced amounts of damage in comparison to conventionally irradiated, where single strand breaks (SSBs) was used as the biological endpoint. This was the case for both hydroxyl scavenging capacities. A reduced electron energy within the VHEE range was also determined to increase the DNA damage to pBR322 plasmid. Results indicate that the pBR322 plasmid model can be successfully used to explore and test the effect of UHDR regimes on DNA damage. This is the first study to report FLASH sparing with VHEE, with induced damage to pBR322 plasmid DNA as the biological endpoint. UHDR irradiated plasmid had reduced amounts of DNA single-strand breaks (SSBs) in comparison with conventional dose rates. The magnitude of the FLASH sparing was a 27% reduction in SSB frequency in a 10 mM Tris environment and a 16% reduction in a 100 mM Tris environment

Surface plasmon-related resonances on deep and asymmetric gold gratings

M. Kreiter, S. Mittler, W. Knoll, and J. Roy Sambles, Physical Review B, Vol. 65, article 125415 (2002). "Copyright © 2002 by the American Physical Society."Based on theoretical calculations, the surface plasmonlike resonances on deep and asymmetric gold gratings are reinvestigated and assigned to two classes possessing different characteristic symmetry properties. Reflectivity measurements on deep grating structures with varying depth and asymmetry allow for a detailed study of the influence of these parameters on the lowest-order resonances as well as the experimental observation of a higher-order resonance

Patient-reported wellbeing and clinical disease measures over time captured by multivariate trajectories of disease activity in individuals with juvenile idiopathic arthritis in the UK: a multicentre prospective longitudinal study

Background: Juvenile idiopathic arthritis (JIA) is a heterogeneous disease, the signs and symptoms of which can be summarised with use of composite disease activity measures, including the clinical Juvenile Arthritis Disease Activity Score (cJADAS). However, clusters of children and young people might experience different global patterns in their signs and symptoms of disease, which might run in parallel or diverge over time. We aimed to identify such clusters in the 3 years after a diagnosis of JIA. The identification of these clusters would allow for a greater understanding of disease progression in JIA, including how physician-reported and patient-reported outcomes relate to each other over the JIA disease course. / Methods: In this multicentre prospective longitudinal study, we included children and young people recruited before Jan 1, 2015, to the Childhood Arthritis Prospective Study (CAPS), a UK multicentre inception cohort. Participants without a cJADAS score were excluded. To assess groups of children and young people with similar disease patterns in active joint count, physician’s global assessment, and patient or parental global evaluation, we used latent profile analysis at initial presentation to paediatric rheumatology and multivariate group-based trajectory models for the following 3 years. Optimal models were selected on the basis of a combination of model fit, clinical plausibility, and model parsimony. / Finding: Between Jan 1, 2001, and Dec 31, 2014, 1423 children and young people with JIA were recruited to CAPS, 239 of whom were excluded, resulting in a final study population of 1184 children and young people. We identified five clusters at baseline and six trajectory groups using longitudinal follow-up data. Disease course was not well predicted from clusters at baseline; however, in both cross-sectional and longitudinal analyses, substantial proportions of children and young people had high patient or parent global scores despite low or improving joint counts and physician global scores. Participants in these groups were older, and a higher proportion of them had enthesitisrelated JIA and lower socioeconomic status, compared with those in other groups. / Interpretation: Almost one in four children and young people with JIA in our study reported persistent, high patient or parent global scores despite having low or improving active joint counts and physician’s global scores. Distinct patient subgroups defined by disease manifestation or trajectories of progression could help to better personalise health-care services and treatment plans for individuals with JIA. / Funding: Medical Research Council, Versus Arthritis, Great Ormond Street Hospital Children’s Charity, Olivia’s Vision, and National Institute for Health Researc

Can we improve outcome of congenital diaphragmatic hernia?

This review gives an overview of the disease spectrum of congenital diaphragmatic hernia (CDH). Etiological factors, prenatal predictors of survival, new treatment strategies and long-term morbidity are described. Early recognition of problems and improvement of treatment strategies in CDH patients may increase survival and prevent secondary morbidity. Multidisciplinary healthcare is necessary to improve healthcare for CDH patients. Absence of international therapy guidelines, lack of evidence of many therapeutic modalities and the relative low number of CDH patients calls for cooperation between centers with an expertise in the treatment of CDH patients. The international CDH Euro-Consortium is an example of such a collaborative network, which enhances exchange of knowledge, future research and development of treatment protocols

Alterations in pulmonary vascular function in rats exposed to intermittent hypoxia

Vasoactive agents were examined in arteries from control rats and rats exposed to intermittent hypoxia (10% oxygen; 8 h/day) for 3, 5 or 20 days. Hypoxic rats developed right ventricular hypertrophy after 5 days, but became pulmonary hypertensive (elevated right ventricular systolic pressure; RVSP) only after 20 days. In pulmonary arteries (main and intralobar), responses to acetylcholine and ionomycin (endothelium-dependent vasodilators) were reduced after 20 and 5 days of intermittent hypoxia, whereas contractions to 5-hydroxytryptamine (5-HT) were enhanced (potency increase >10-fold) after 20, 5 and 3 days. Contractions to endothelin-1 and a thromboxane-mimetic, but not Ca-2divided by, were also increased. No changes in vascular function occurred in aorta. Since changes in pulmonary vascular function preceded the increase in RVSP they do not result from, but may contribute to, the development of hypoxia-induced pulmonary hypertension. If similar changes occur in humans, they may be important in conditions characterised by intermittent, as opposed to continuous, hypoxia. (C) 2003 Elsevier B.V. All rights reserved