Pathological margins and advanced cutaneous squamous cell carcinoma of the head and neck.

OBJECTIVE:The recommended treatment for cutaneous squamous cell cancer (CuSCC) of the head and neck is Mohs surgical excision or wide local excision. Excision is recommended to a gross surgical margin of 4-6 mm however this is based on limited evidence and specify a goal histologic margin. The objective of this study was therefore to examine the reported histological margin distance following WLE of advanced CuSCC and its association with recurrence and survival. STUDY DESIGN:Retrospective database review. SETTING:All patients included received treatment at UC Davis Department of Otolaryngology-Head and Neck Surgery and/or Radiation Oncology in Sacramento, California. SUBJECTS AND METHODS:The patients included were treated for advanced CuSCC with primary surgery with or without adjuvant therapy. Kaplan Meier survival curves with log rank analysis were then performed to compare 5-year recurrence free survival, and disease-specific survival for patients with different margin distances. RESULTS:Total number of subjects was 92. The overall 5-year DSS and RFS was 68.8 and 51.0% respectively. When the pathological margin distance was ≥5 mm, 5-year disease specific survival was improved when compared to margin distance less than 5 mm (94.7 vs 60.7 p = 0.034). CONCLUSION:The findings of this study suggest that a histologic margin of at least 5 mm may increase survival in advanced head and neck CuSCC patients

Universal scaling of local plasmons in chains of metal spheres

The position, width, extinction, and electric field of localized plasmon modes in closely-coupled linear chains of small spheres are investigated. A dipole-like model is presented that separates the universal geometric factors from the specific metal permittivity. An electrostatic surface integral method is used to deduce universal parameters that are confirmed against results for different metals (bulk experimental Ag, Au, Al, K) calculated using retarded vector spherical harmonics and finite elements. The mode permittivity change decays to an asymptote with the number of particles in the chain, and changes dramatically from 1/f3to 1/f 1/2 as the gap fraction (ratio of gap between spheres to their diameter), f, gets smaller. Scattering increases significantly with closer coupling. The mode sharpness, strength and electric field for weakly retarded calculations are consistent with electrostatic predictions once the effect of radiative damping is accounted for. ©2010 Optical Society of America

Spectral Characterization of the AisaOWL

The AisaOWL is a recent-to-market thermal hyperspectral instrument. As such, there is little information about the sensor performance in the literature. The sensor covers the 7.6 to 12.6~$\mu m$ part of the Long Wave Infra-Red region with 102 continuous bands, and is capable of imaging in low-light conditions. This paper presents an independent characterisation of the AisaOWL sensor, examining the spectral accuracy of black body measurements at different temperatures and validating manufacturer recommendations for warm-up, integration and calibration times. This analysis is essential for establishing high quality operational procedures and in giving confidence to users of the data. In this study the sensor has been found to have a maximum error of 2~\textdegree C in absolute temperature measurement, and provides spectra most accurate in the 8 to 9~$\mu m$ region. The recommended warm-up time of 15 minutes has been confirmed, with a 1~\% increase in error identified for data collected only 7 minutes after switch on. The optimal integration time of 1.18~ms has been validated and an exponential decrease in performance observed outside the 0.85 to 1.2~ms range. The detector used by the sensor is shown to have stability issues and this has been examined by comparing black body data processed with different calibration data. While the detector is operating in a stable regime compatible with the calibration, these black body readings stay within 5~\% across the central bands, approaching 10~\% below 8~$\mu m$ and just exceeding 20~\% above 11~$\mu m$

Plasmon absorption in nanospheres: A comparison of sodium, potassium, aluminium, silver and gold

The optical absorption for nanospheres made from Na, K, Al, Ag and Au are compared as a precursor to choosing the ideal metal for use in a negative permittivity (NP) near-field superlens. The relationship between optical absorption of the metal nanosphere and the ability of the NP lens to reconstruct the near field is one to one. Metals with low dielectric losses have large plasmon absorption cross-sections and absorb over a very narrow wavelength range; they are consequently excellent materials for superlenses. Numerical solutions to Mie theory were used to calculate the absorption efficiency, Qabs, for nanospheres varying in radius between 5 and 100 nm in vacuum. We show that, although silver is the most commonly used material for superlensing, its absorption efficiency, as a nanosphere, at the plasmon resonance is not as strong as materials such as the alkali metals. Of all these materials, potassium spheres with a radius of 21 nm have an optimum absorption efficiency of 14.7, resulting in the ability of a film with thickness of 40 nm to reconstruct a grating with a period of 57 nm. © 2007 Elsevier B.V. All rights reserved

Epigenetic differences in monozygotic twins discordant for major depressive disorder

Although monozygotic (MZ) twins share the majority of their genetic makeup, they can be phenotypically discordant on several traits and diseases. DNA methylation is an epigenetic mechanism that can be influenced by genetic, environmental and stochastic events and may have an important impact on individual variability. In this study we explored epigenetic differences in peripheral blood samples in three MZ twin studies on major depressive disorder (MDD). Epigenetic data for twin pairs were collected as part of a previous study using 8.1-K-CpG microarrays tagging DNA modification in white blood cells from MZ twins discordant for MDD. Data originated from three geographical regions: UK, Australia and the Netherlands. Ninety-seven MZ pairs (194 individuals) discordant for MDD were included. Different methods to address non independently-and-identically distributed (non-i.i.d.) data were evaluated. Machine-learning methods with feature selection centered on support vector machine and random forest were used to build a classifier to predict cases and controls based on epivariations. The most informative variants were mapped to genes and carried forward for network analysis. A mixture approach using principal component analysis (PCA) and Bayes methods allowed to combine the three studies and to leverage the increased predictive power provided by the larger sample. A machine-learning algorithm with feature reduction classified affected from non-affected twins above chance levels in an independent training-testing design. Network analysis revealed gene networks centered on the PPAR-γ (NR1C3) and C-MYC gene hubs interacting through the AP-1 (c-Jun) transcription factor. PPAR-γ (NR1C3) is a drug target for pioglitazone, which has been shown to reduce depression symptoms in patients with MDD. Using a data-driven approach we were able to overcome challenges of non-i.i.d. data when combining epigenetic studies from MZ twins discordant for MDD. Individually, the studies yielded negative results but when combined classification of the disease state from blood epigenome alone was possible. Network analysis revealed genes and gene networks that support the inflammation hypothesis of MDD

Plasmonic resonances of closely coupled gold nanosphere chains

The optical properties of an ordered array of gold nanospheres have been calculated using the T-matrix method in the regime where the near-fields of the particles are strongly coupled. The array consists of a one-dimensional chain of spheres of 15 nm diameter where the number of spheres in the chain and interparticle spacing is varied. Calculations have been performed with chains up to 150 particles in length and with an interparticle spacing between 0.5 and 30 nm. Incident light polarized along the axis of the chain (longitudinal) and perpendicular (transverse) to it are considered, and in the latter case for wavevectors along and perpendicular to the chain axis. For fixed chain length the longitudinal plasmon resonance red shifts, relative to the resonance of an isolated sphere, as the interparticle spacing is reduced. The shift in the plasmon resonance does not appear to follow an exponential dependence upon gap size for these extended arrays of particles. The peak shift is inversely proportional to the distance, a result that is consistent with the van der Waals attraction between two spheres at short range, which also varies as 1/d. The transverse plasmon resonance shifts in the opposite direction as the interparticle gap is reduced; this shift is considerably smaller and approaches 500 nm as the gap tends to zero. Increasing the number of particles in the chain for a fixed gap has a similar effect on the longitudinal and transverse plasmon. In this case, however, the longitudinal plasmon tends toward an asymptotic value with increasing chain length, with the asymptotic value determined by the interparticle spacing. Here, the approach to the asymptote is exponential with a characteristic length of approximately two particles, at small interparticle spacings. This approach to an asymptote as the chain length becomes infinite has been verified in a finite element calculation with periodic boundary conditions. © 2009 American Chemical Society

The Economic Roots of Anti-immigrant Prejudice in the Global South: Evidence from South Africa

Most research in developed countries on prejudice toward foreign-born minorities suggests that cultural rather than economic threat motivates xenophobia. Prior studies leave unanswered questions about the origins of anti-immigrant prejudice in developing countries, where one-third of worldwide immigration occurs. Alternatively, developing-country research simply assumes that economic threat drives prejudice in the global South but has not presented credible empirical evidence. In this study, we seek to reliably measure anti-immigrant prejudice and examine possible determinants of prejudice and prejudice-based voting behavior. Through a list experiment conducted on a random sample of South Africans (N = 1,088), we investigate the predictive power of economic threat theory in explaining prejudice toward immigrants in South Africa. The results show that significant prejudice toward immigrants exists among South Africans and that such prejudice is higher among the unemployed, but these sentiments do not seem to influence vote choice. The evidence suggests that the determinants of anti-immigrant sentiments due to South-South migration are distinct from South-North migration

Who Controls Foreign Aid? Elite versus Public Perceptions of Donor Influence in Aid-Dependent Uganda

Does foreign aid enable or constrain elite capture of public revenues? Reflecting on prominent debates in the foreign aid literature, we examine whether recipient preferences are consistent with a view that foreign donors wield substantial control over the flow of aid dollars, making elite capture more difficult and mass benefits more likely. We compare elite and mass support for foreign aid versus government spending on development projects through a survey experiment with behavioral outcomes. A key innovation is a parallel experiment on members of the Ugandan national parliament and a representative sample of Ugandan citizens. For two actual aid projects, we randomly assigned different funders to the projects. Significant treatment effects reveal that members of parliament support government programs over foreign aid, whereas citizens prefer aid over government. Donor control also implies that citizens should favor foreign aid more and elites less as their perceptions of government clientelism and corruption increase. We explore this and report on other alternative mechanisms. Effects for citizens and elites are most apparent for those perceiving significant government corruption, suggesting that both sets of subjects perceive significant donor control over aid

Optimisation of absorption efficiency for varying dielectric spherical nanoparticles

In this paper we compare the optical absorption for nanospheres made from a range of transition and alkali metals from Li (A=3) to Au (A=79). Numerical solutions to Mie theory were used to calculate the absorption efficiency, Q abs, for nanospheres varying in radii between 5 nm and 100 nm in vacuum. We show that, although gold is the most commonly used nanoparticle material, its absorption efficiency at the plasmon resonance is not as strong as materials such as the alkali metals. Of all the materials tried, potassium spheres with a radius of 21 nm have an optimum absorption efficiency of 14.7. In addition we also show that, unlike gold, the wavelength of the plasmon peak in other materials is sensitive to the sphere radius. In potassium the peak position shifts by 100 nm for spheres ranging from 5 nm to 65 nm, the shift is less than 10 nm for gold spheres. © 2006 IEEE

The Hubble Constant from Observations of the Brightest Red Giant Stars in a Virgo-Cluster Galaxy

The Virgo and Fornax clusters of galaxies play central roles in determining the Hubble constant H_0. A powerful and direct way of establishing distances for elliptical galaxies is to use the luminosities of the brightest red-giant stars (the TRGB luminosity, at M_I = -4.2). Here we report the direct observation of the TRGB stars in a dwarf elliptical galaxy in the Virgo cluster. We find its distance to be 15.7 +- 1.5 Megaparsecs, from which we estimate a Hubble constant of H_0 = 77 +- 8 km/s/Mpc. Under the assumption of a low-density Universe with the simplest cosmology, the age of the Universe is no more than 12-13 billion years.Comment: 12 pages, LaTeX, with 2 postscript figures; in press for Nature, July 199