303 research outputs found

    Comment on 'Tumour antigen expression in hepatocellular carcinoma in a low-endemic western area'

    Get PDF
    We comment on the recent study by Sideras et al (2015) that combines tissue microarrays (TMAs) and immunohistochemistry to investigate the expression pattern of 15 antigens belonging to different categories, including cancer-testis antigens and oncofetal proteins in hepatocellular carcinoma (HCC). Because current therapies for HCC are far from ideal (Ilan, 2014) and immunotherapy has been suggested as a potential therapeutic option, the Authors aimed at identifying a panel of biologically relevant tumour antigens with broad expression in a western European population of HCC patients and specific expression in the tumour tissue with no, or little, expression in surrounding non- tumoral tissue (Sideras et al., 2015)

    Unravelling quantum carpets: a travelling wave approach

    Get PDF
    Quantum carpets are generic spacetime patterns formed in the probability distributions P(x,t) of one-dimensional quantum particles, first discovered in 1995. For the case of an infinite square well potential, these patterns are shown to have a detailed quantitative explanation in terms of a travelling-wave decomposition of P(x,t). Each wave directly yields the time-averaged structure of P(x,t) along the (quantised)spacetime direction in which the wave propagates. The decomposition leads to new predictions of locations, widths depths and shapes of carpet structures, and results are also applicable to light diffracted by a periodic grating and to the quantum rotator. A simple connection between the waves and the Wigner function of the initial state of the particle is demonstrated, and some results for more general potentials are given.Comment: Latex, 26 pages + 6 figures, submitted to J. Phys. A (connections with prior literature clarified

    Exact results for `bouncing' Gaussian wave packets

    Full text link
    We consider time-dependent Gaussian wave packet solutions of the Schrodinger equation (with arbitrary initial central position, x_0, and momentum, p_0, for an otherwise free-particle, but with an infinite wall at x=0, so-called bouncing wave packets. We show how difference or mirror solutions of the form psi(x,t)-psi(-x,t) can, in this case, be normalized exactly, allowing for the evaluation of a number of time-dependent expectation values and other quantities in closed form. For example, we calculate _t explicitly which illustrates how the free-particle kinetic (and hence total) energy is affected by the presence of the distant boundary. We also discuss the time dependence of the expectation values of position, _t, and momentum, _t, and their relation to the impulsive force during the `collision' with the wall. Finally, the x_0,p_0 --> 0 limit is shown to reduce to a special case of a non-standard free-particle Gaussian solution. The addition of this example to the literature then expands on the relatively small number of Gaussian solutions to quantum mechanical problems with familiar classical analogs (free particle, uniform acceleration, harmonic oscillator, unstable oscillator, and uniform magnetic field) available in closed form.Comment: 14 pages, 1 embedded .eps figur

    Quantum carpet interferometry for trapped atomic Bose-Einstein condensates

    Full text link
    We propose an ``interferometric'' scheme for Bose-Einstein condensates using near-field diffraction. The scheme is based on the phenomenon of intermode traces or quantum carpets; we show how it may be used in the detection of weak forces.Comment: 4 figures. Submitted to Phys. Rev.

    Superrevivals in the quantum dynamics of a particle confined in a finite square well potential

    Get PDF
    We examine the revival features in wave packet dynamics of a particle confined in a finite square well potential. The possibility of tunneling modifies the revival pattern as compared to an infinite square well potential. We study the dependence of the revival times on the depth of the square well and predict the existence of superrevivals. The nature of these superrevivals is compared with similar features seen in the dynamics of wavepackets in an anharmonic oscillator potential.Comment: 8 pages in Latex two-column format with 5 figures (eps). To appear in Physical Review

    Opportunities for the Primary Prevention of Obesity during Infancy

    Get PDF
    Are chubby babies healthy babies? Whereas most seem well during infancy, evidence is increasing that heavier babies have a poorer long-term health trajectory than their trimmer counterparts. Data have emerged over the past 2 decades that early life growth patterns and behaviors play an important role in the etiology of obesity, yet there has been very little focus on the primary prevention of obesity during infancy by the medical, behavioral health, and public health communities. A recent report from the National Health and Nutrition Examination Survey (NHANES) highlighted the need for very early intervention when it revealed that between 2003 and 2006, a staggering 24.4% of children aged 2 to 5 years already were overweight or obese (body mass index [BMI; calculated as the weight in kilograms divided by height in meters squared] 85th–94th and ≥95th percentiles, respectively) [1]. NHANES data also have described obesity (weight-for-length/height ≥95th percentile) among infants younger than 2 years ( Fig. 1). Between the late 1970s and 2000, the prevalence of obesity among infants 6 to 23 months old increased by more than 60% [2]. Reports from the Centers for Disease Control and Prevention (CDC) Pediatric Nutrition Surveillance System [3] and a Massachusetts Health Maintenance Organization [4] similarly showed significant increases in the prevalence of overweight for infants and toddlers for all age groups since the 1980

    Self-interference of a single Bose-Einstein condensate due to boundary effects

    Full text link
    A simple model wavefunction, consisting of a linear combination of two free-particle Gaussians, describes many of the observed features seen in the interactions of two isolated Bose-Einstein condensates as they expand, overlap, and interfere. We show that a simple extension of this idea can be used to predict the qualitative time-development of a single expanding BEC condensate produced near an infinite wall boundary, giving similar interference phenomena. We also briefly discuss other possible time-dependent behaviors of single BEC condensates in restricted geometries,such as wave packet revivals.Comment: 8 pages, no figures, to appear in Physica Script

    Optimum spectral window for imaging of art with optical coherence tomography

    Get PDF
    Optical Coherence Tomography (OCT) has been shown to have potential for important applications in the field of art conservation and archaeology due to its ability to image subsurface microstructures non-invasively. However, its depth of penetration in painted objects is limited due to the strong scattering properties of artists’ paints. VIS-NIR (400 nm – 2400 nm) reflectance spectra of a wide variety of paints made with historic artists’ pigments have been measured. The best spectral window with which to use optical coherence tomography (OCT) for the imaging of subsurface structure of paintings was found to be around 2.2 μm. The same spectral window would also be most suitable for direct infrared imaging of preparatory sketches under the paint layers. The reflectance spectra from a large sample of chemically verified pigments provide information on the spectral transparency of historic artists’ pigments/paints as well as a reference set of spectra for pigment identification. The results of the paper suggest that broadband sources at ~2 microns are highly desirable for OCT applications in art and potentially material science in general

    Comparison of age-specific cataract prevalence in two population-based surveys 6 years apart

    Get PDF
    BACKGROUND: In this study, we aimed to compare age-specific cortical, nuclear and posterior subcapsular (PSC) cataract prevalence in two surveys 6 years apart. METHODS: The Blue Mountains Eye Study examined 3654 participants (82.4% of those eligible) in cross-section I (1992–4) and 3509 participants (75.1% of survivors and 85.2% of newly eligible) in cross-section II (1997–2000, 66.5% overlap with cross-section I). Cataract was assessed from lens photographs following the Wisconsin Cataract Grading System. Cortical cataract was defined if cortical opacity comprised ≥ 5% of lens area. Nuclear cataract was defined if nuclear opacity ≥ Wisconsin standard 4. PSC was defined if any present. Any cataract was defined to include persons who had previous cataract surgery. Weighted kappa for inter-grader reliability was 0.82, 0.55 and 0.82 for cortical, nuclear and PSC cataract, respectively. We assessed age-specific prevalence using an interval of 5 years, so that participants within each age group were independent between the two surveys. RESULTS: Age and gender distributions were similar between the two populations. The age-specific prevalence of cortical (23.8% in 1(st), 23.7% in 2(nd)) and PSC cataract (6.3%, 6.0%) was similar. The prevalence of nuclear cataract increased slightly from 18.7% to 23.9%. After age standardization, the similar prevalence of cortical (23.8%, 23.5%) and PSC cataract (6.3%, 5.9%), and the increased prevalence of nuclear cataract (18.7%, 24.2%) remained. CONCLUSION: In two surveys of two population-based samples with similar age and gender distributions, we found a relatively stable cortical and PSC cataract prevalence over a 6-year period. The increased prevalence of nuclear cataract deserves further study
    corecore