The performance of active coated nanoparticles based on quantum-dot gain media

Quantum-dots (QDs) provide an exciting option for the gain media incorporated in active coated nanoparticles (CNPs) because they possess large gain coefficients resulting from their extreme confinement effects. The optical properties of core/shell QDs can be tuned by changing the relative size of the core/shell, that is, by effectively changing its band gap structure. Similarly, the resonance of a CNP can be adjusted by changing the relative sizes of its layers. It is demonstrated here that by optimally locating the QDs inside a resonant CNP structure it is possible to greatly enhance the intrinsic amplifying behavior of the combined QD-CNP system. © 2012 Sawyer D. Campbell and Richard W. Ziolkowski

Revisiting the relativistic ejection event in XTE J1550-564 during the 1998 outburst

We revisit the discovery outburst of the X-ray transient XTE J1550−564 during which relativistic jets were observed in 1998 September, and review the radio images obtained with the Australian Long Baseline Array, and light curves obtained with the Molonglo Observatory Synthesis Telescope and the Australia Telescope Compact Array. Based on Hi spectra, we constrain the source distance to between 3.3 and 4.9 kpc. The radio images, taken some 2 d apart, show the evolution of an ejection event. The apparent separation velocity of the two outermost ejecta is at least 1.3c and may be as large as 1.9c; when relativistic effects are taken into account, the inferred true velocity is ≥ 0.8c. The flux densities appear to peak simultaneously during the outburst, with a rather flat (although still optically thin) spectral index of −0.2

Anisotropic permittivity of ultra-thin crystalline Au films: Impacts on the plasmonic response of metasurfaces

It has been determined by density functional theory (DFT) simulations that the extracted permittivities of ultra-thin crystalline gold (Au) films exhibit large anisotropies which are not predicted by classical models or previous experimental determinations of the dielectric function. The optical scattering characteristics of a periodic array of Au discs are simulated with the DFT extracted permittivity and contrasted against those obtained with several commonly used Au permittivity models. It is demonstrated that the DFT-based transmittance spectra for these plasmonic metasurfaces lead to significantly redshifted results when compared to those predicted by standard Drude and Johnson-Christy permittivity models. © 2013 AIP Publishing LLC

No excess of mitochondrial DNA deletions within muscle in progressive multiple sclerosis

BACKGROUND: Mitochondrial dysfunction is an established feature of multiple sclerosis (MS). We recently described high levels of mitochondrial DNA (mtDNA) deletions within respiratory enzyme-deficient (lacking mitochondrial respiratory chain complex IV with intact complex II) neurons and choroid plexus epithelial cells in progressive MS. OBJECTIVES: The objective of this paper is to determine whether respiratory enzyme deficiency and mtDNA deletions in MS were in excess of age-related changes within muscle, which, like neurons, are post-mitotic cells that frequently harbour mtDNA deletions with ageing and in disease. METHODS: In progressive MS cases (n=17), known to harbour an excess of mtDNA deletions in the central nervous system (CNS), and controls (n=15), we studied muscle (paraspinal) and explored mitochondria in single fibres. Histochemistry, immunohistochemistry, laser microdissection, real-time polymerase chain reaction (PCR), long-range PCR and sequencing were used to resolve the single muscle fibres. RESULTS: The percentage of respiratory enzyme-deficient muscle fibres, mtDNA deletion level and percentage of muscle fibres harbouring high levels of mtDNA deletions were not significantly different in MS compared with controls. CONCLUSION: Our findings do not provide support to the existence of a diffuse mitochondrial abnormality involving multiple systems in MS. Understanding the cause(s) of the CNS mitochondrial dysfunction in progressive MS remains a research priority

Vector boson pair production at the LHC

We present phenomenological results for vector boson pair production at the LHC, obtained using the parton-level next-to-leading order program MCFM. We include the implementation of a new process in the code, pp -> \gamma\gamma, and important updates to existing processes. We incorporate fragmentation contributions in order to allow for the experimental isolation of photons in \gamma\gamma, W\gamma, and Z\gamma production and also account for gluon-gluon initial state contributions for all relevant processes. We present results for a variety of phenomenological scenarios, at the current operating energy of \sqrt{s} = 7 TeV and for the ultimate machine goal, \sqrt{s} = 14 TeV. We investigate the impact of our predictions on several important distributions that enter into searches for new physics at the LHC.Comment: 35 pages, 14 figure

Protection against Experimental Melioidosis with a Synthetic manno-Heptopyranose Hexasaccharide Glycoconjugate

This is the final version of the article. Available from the publisher via the DOI in this record.Melioidosis is an emerging infectious disease caused by Burkholderia pseudomallei and is associated with high morbidity and mortality rates in endemic areas. Antibiotic treatment is protracted and not always successful; even with appropriate therapy, up to 40% of individuals presenting with melioidosis in Thailand succumb to infection. In these circumstances, an effective vaccine has the potential to have a dramatic impact on both the scale and the severity of disease. Currently, no vaccines are licensed for human use. A leading vaccine candidate is the capsular polysaccharide consisting of a homopolymer of unbranched 1→3 linked 2-O-acetyl-6-deoxy-β-d-manno-heptopyranose. Here, we present the chemical synthesis of this challenging antigen using a novel modular disaccharide assembly approach. The resulting hexasaccharide was coupled to the nontoxic Hc domain of tetanus toxin as a carrier protein to promote recruitment of T-cell help and provide a scaffold for antigen display. Mice immunized with the glycoconjugate developed IgM and IgG responses capable of recognizing native capsule, and were protected against infection with over 120 × LD50 of B. pseudomallei strain K96243. This is the first report of the chemical synthesis of an immunologically relevant and protective hexasaccharide fragment of the capsular polysaccharide of B. pseudomallei and serves as the rational starting point for the development of an effective licensed vaccine for this emerging infectious disease.This work was funded by the United Kingdom Ministry of Defence. The mass spectral data described here were acquired on an Orbitrap Fusion mass spectrometer funded by National Institutes of Health grant 1S10OD010645-01A1

Experiential aspects of tourism gift consumption

This article addresses how consumers make use of fantasy, feelings, and fun when deciding, giving, and consuming gifts of tourism and leisure. Despite little industry awareness, consumers are engaging with such behaviour because tourism gifts offer considerable scope for the creative expression of donor–recipient relationships. This UK-based interpretive qualitative study captured data from donors, recipients, and tourism and leisure providers. The feelings (emotions), fantasies (imagination and dreaming), and fun (playfulness) were interrogated through the behavioural phases of gift decision making, gift exchange, post-exchange, and gift consumption. A range of emotions were displayed by donors and recipients at different stages in the gift-giving process; donor decision making in groups for created gifts was particularly charged. Fantasies were evident both for donors planning gifts and for recipients. As an intangible gift, means of exchange allowed for creative mechanisms beyond the classic wrapping strategies associated with physical gifts. The ‘decoy’ strategy stimulated the recipient’s imagination to conjure fantastical scenarios. Fun or playfulness was built into many of the gifts and often related to an element of ‘surprise’, an attribute of the perfect gift (e.g. Belk, 1996) in Western societies