4,208 research outputs found

    Human papillomavirus infection in esophageal squamous cell carcinoma and esophageal adenocarcinoma: a concise review

    Full text link
    The causal link between high-risk human papillomavirus (hr-HPV) infection and cervical, anogenital, and some oropharyngeal malignancies has been established by both molecular and epidemiological data. The association between HPV and esophageal squamous cell carcinoma (ESCC) remains controversial, as is the true prevalence of HPV infection in ESCC. The wide range in reported rates reflects variability in the primary literature, with some larger scale case–control studies suggesting the infection rates range from 0% to 78%. Interactions between HPV and the Barrett's metaplasia–dysplasia–carcinoma sequence have been explored, and these studies have shown some conflicting data. Overall, systematic reviews have reported the prevalence of HPV-positive DNA in esophageal adenocarcinoma patients of between 13% and 35%. Postulated reasons for discrepancies in HPV prevalence rates in esophageal cancer include variations in testing methodology and assay sensitivities; technical issues, including the lack of a gold-standard primer; types of specimens utilized (fresh-frozen versus formalin-fixed tissue); geographical variation; cross-contamination; and small sample sizes. Thus, efforts must be undertaken to (1) standardize HPV testing, ideally in a central laboratory and utilizing tests that detect viral transcriptional activity; (2) avoid cross-contamination; and (3) recruit large numbers of patients to accurately ascertain HPV rates in esophageal malignancy

    Kochen-Specker Vectors

    Full text link
    We give a constructive and exhaustive definition of Kochen-Specker (KS) vectors in a Hilbert space of any dimension as well as of all the remaining vectors of the space. KS vectors are elements of any set of orthonormal states, i.e., vectors in n-dim Hilbert space, H^n, n>3 to which it is impossible to assign 1s and 0s in such a way that no two mutually orthogonal vectors from the set are both assigned 1 and that not all mutually orthogonal vectors are assigned 0. Our constructive definition of such KS vectors is based on algorithms that generate MMP diagrams corresponding to blocks of orthogonal vectors in R^n, on algorithms that single out those diagrams on which algebraic 0-1 states cannot be defined, and on algorithms that solve nonlinear equations describing the orthogonalities of the vectors by means of statistically polynomially complex interval analysis and self-teaching programs. The algorithms are limited neither by the number of dimensions nor by the number of vectors. To demonstrate the power of the algorithms, all 4-dim KS vector systems containing up to 24 vectors were generated and described, all 3-dim vector systems containing up to 30 vectors were scanned, and several general properties of KS vectors were found.Comment: 19 pages, 6 figures, title changed, introduction thoroughly rewritten, n-dim rotation of KS vectors defined, original Kochen-Specker 192 (117) vector system translated into MMP diagram notation with a new graphical representation, results on Tkadlec's dual diagrams added, several other new results added, journal version: to be published in J. Phys. A, 38 (2005). Web page: http://m3k.grad.hr/pavici

    Measurement of atmospheric nitrous acid at Blodgett Forest during BEARPEX2007

    Get PDF
    Nitrous acid (HONO) is an important precursor of the hydroxyl radical (OH) in the lower troposphere. Understanding HONO chemistry, particularly its sources and contribution to HO_x (=OH+HO_2) production, is very important for understanding atmospheric oxidation processes. A highly sensitive instrument for detecting atmospheric HONO based on wet chemistry followed by liquid waveguide long path absorption photometry was deployed in the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX) at Blodgett Forest, California in late summer 2007. The median diurnal variation shows minimum HONO levels of about 20–30 pptv during the day and maximum levels of about 60–70 pptv at night, a diurnal pattern quite different from the results at various other forested sites. Measured HONO/NO_2 ratios for a 24-h period ranged from 0.05 to 0.13 with a mean ratio of 0.07. Speciation of reactive nitrogen compounds (NO_y) indicates that HONO accounted for only ~3% of total NO_y. However, due to the fast HONO loss through photolysis, a strong HONO source (1.59 ppbv day^(−1)) existed in this environment in order to sustain the observed HONO levels, indicating the significant role of HONO in NO_y cycling. The wet chemistry HONO measurements were compared to the HONO measurements made with a Chemical Ionization Mass Spectrometer (CIMS) over a three-day period. Good agreement was obtained between the measurements from the two different techniques. Using the expansive suite of photochemical and meteorological measurements, the contribution of HONO photolysis to HO_x budget was calculated to be relatively small (6%) compared to results from other forested sites. The lower HONO mixing ratio and thus its smaller contribution to HO_x production are attributed to the unique meteorological conditions and low acid precipitation at Blodgett Forest. Further studies of HONO in this kind of environment are needed to test this hypothesis and to improve our understanding of atmospheric oxidation and nitrogen budget

    Retrospective case note review of chronic spontaneous urticaria outcomes and adverse effects in patients treated with omalizumab or ciclosporin in UK secondary care.

    Get PDF
    BACKGROUND: Omalizumab is approved in the UK as add-on treatment for chronic spontaneous urticaria (CSU) in patients with inadequate response to H1-antihistamines. Ciclosporin is an established but unlicensed 3rd line option for CSU. Two parallel retrospective observational studies were conducted to describe outcomes of treatment and adverse events with omalizumab or ciclosporin for CSU treatment. METHODS: Data from UK specialist centres prescribing omalizumab (five centres) or ciclosporin (three centres) in CSU patients were collected from hospital records by clinical staff and pooled for analysis. RESULTS: Forty-six patients prescribed omalizumab and 72 patients prescribed ciclosporin were included. Twenty-two (48%) omalizumab-treated patients had paired Urticaria Activity Scores (UAS7), showing a 25.4 point improvement during treatment (P < 0.0001). Paired Dermatology Life Quality Index (DLQI) was available in 28 (61%) omalizumab-treated and 17 (24%) ciclosporin-treated patients. At least a 75% improvement in DLQI score was observed in 79% of omalizumab-treated and 41% of ciclosporin-treated patients, and 65% of omalizumab-treated patients had complete resolution of their quality-of-life impairment (DLQI 0-1) versus 21% of ciclosporin-treated patients. Clinician comments reported symptom clearance in 15/36 (42%) omalizumab-treated and 10/60 (17%) ciclosporin-treated patients. Proportions of patients with adverse events were similar but those for omalizumab resembled CSU symptoms, making causality assignment difficult, whereas those for ciclosporin were consistent with its known adverse effect profile. CONCLUSIONS: Validated patient-reported measures of disease severity and quality of life should be used routinely in CSU management. Based on clinician comments and DLQI scores, symptoms and quality of life showed a greater improvement in the omalizumab-treated cohort than in the ciclosporin-treated cohort

    Reconstructing pedigrees: some identifiability questions for a recombination-mutation model

    Full text link
    Pedigrees are directed acyclic graphs that represent ancestral relationships between individuals in a population. Based on a schematic recombination process, we describe two simple Markov models for sequences evolving on pedigrees - Model R (recombinations without mutations) and Model RM (recombinations with mutations). For these models, we ask an identifiability question: is it possible to construct a pedigree from the joint probability distribution of extant sequences? We present partial identifiability results for general pedigrees: we show that when the crossover probabilities are sufficiently small, certain spanning subgraph sequences can be counted from the joint distribution of extant sequences. We demonstrate how pedigrees that earlier seemed difficult to distinguish are distinguished by counting their spanning subgraph sequences.Comment: 40 pages, 9 figure

    Inferring Properties of Ancient Cyanobacteria from Biogeochemical Activity and Genomes of Siderophilic Cyanobacteria

    Get PDF
    Interrelationships between life and the planetary system could have simultaneously left landmarks in genomes of microbes and physicochemical signatures in the lithosphere. Verifying the links between genomic features in living organisms and the mineralized signatures generated by these organisms will help to reveal traces of life on Earth and beyond. Among contemporary environments, iron-depositing hot springs (IDHS) may represent one of the most appropriate natural models [1] for insights into ancient life since organisms may have originated on Earth and probably Mars in association with hydrothermal activity [2,3]. IDHS also seem to be appropriate models for studying certain biogeochemical processes that could have taken place in the late Archean and,-or early Paleoproterozoic eras [4, 5]. It has been suggested that inorganic polyphosphate (PPi), in chains of tens to hundreds of phosphate residues linked by high-energy bonds, is environmentally ubiquitous and abundant [6]. Cyanobacteria (CB) react to increased heavy metal concentrations and UV by enhanced generation of PPi bodies (PPB) [7], which are believed to be signatures of life [8]. However, the role of PPi in oxygenic prokaryotes for the suppression of oxidative stress induced by high Fe is poorly studied. Here we present preliminary results of a new mechanism of Fe mineralization in oxygenic prokaryotes, the effect of Fe on the generation of PPi bodies in CB, as well as preliminary analysis of the diversity and phylogeny of proteins involved in the prevention of oxidative stress in phototrophs inhabiting IDHS

    Correlations in Two-Dimensional Vortex Liquids

    Full text link
    We report on a high temperature perturbation expansion study of the superfluid-density spatial correlation function of a Ginzburg-Landau-model superconducting film in a magnetic field. We have derived a closed form which expresses the contribution to the correlation function from each graph of the perturbation theory in terms of the number of Euler paths around appropriate subgraphs. We have enumerated all graphs appearing out to 10-th order in the expansion and have evaluated their contributions to the correlation function. Low temperature correlation functions, obtained using Pad\'{e} approximants, are in good agreement with Monte Carlo simulation results and show that the vortex-liquid becomes strongly correlated at temperatures well above the vortex solidification temperature.Comment: 18 pages (RevTeX 3.0) and 4 figures, available upon request, IUCM93-01
    corecore