56 research outputs found

    PRACTICAL EXPLORATION OF LOW-COST YET HIGHLY ACCURATE 3D MAPPING TECHNIQUES FOR DOCUMENTATION AND CONSERVATION OF AN EGYPTIAN TOMB (THEBAN TOMB 45)

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    This research presents the initial endeavour to perform geo-referenced 3D reconstruction of an ancient Egyptian tomb located on the West Bank of the Nile in Luxor, evaluating low-cost techniques. This study uses low-cost equipment in conjunction with simple geodetical principles to accurately map a tomb in 3D to empower archaeological teams with limited budgets to efficiently and effectively map their projects. Emphasizing the project goals of both high detail and high accuracy, one of our chosen techniques is photogrammetry with a standard system camera. Additionally, 3D mapping with a modern smartphone was explored in the tomb and was compared with results from the photogrammetry process. Geo-referencing the underground map in a global grid was also part of the project goals. This research shows that, within certain reasonable constraints, the chosen low-cost techniques successfully achieved all goals of producing a highly detailed, highly accurate, and georeferenced 3D map of the selected tomb (Theban Tomb 45). In this first season of mapping the tomb in 3D, various mapping methods were used and tried and where possible compared. Digitally mapping an ancient, underground Egyptian tomb requires a planned approach. In order to better plan when using low-cost scanning equipment, preliminary research was done for mapping a mostly underground, relatively small but complex to survey ancient Egyptian tomb. Data have been collected with the use of both devices and also with a total station, a laser distance meter and a GNSS (Global Navigation Satellite System) datalogger

    The first multi-wavelength campaign of AXP 4U 0142+61 from radio to hard X-rays

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    For the first time a quasi-simultaneous multi-wavelength campaign has been performed on an Anomalous X-ray Pulsar from the radio to the hard X-ray band. 4U 0142+61 was an INTEGRAL target for 1 Ms in July 2005. During these observations it was also observed in the X-ray band with Swift and RXTE, in the optical and NIR with Gemini North and in the radio with the WSRT. In this paper we present the source-energy distribution. The spectral results obtained in the individual wave bands do not connect smoothly; apparently components of different origin contribute to the total spectrum. Remarkable is that the INTEGRAL hard X-ray spectrum (power-law index 0.79 +/- 0.10) is now measured up to an energy of ~230 keV with no indication of a spectral break. Extrapolation of the INTEGRAL power-law spectrum to lower energies passes orders of magnitude underneath the NIR and optical fluxes, as well as the low ~30 microJy (2 sigma) upper limit in the radio band.Comment: 6 pages, 1 figure. To be published in the proceedings of the conference "Isolated Neutron Stars: from the Interior to the Surface" (April 24-28, 2006, London, UK), eds. S. Zane, R. Turolla and D. Pag

    Carbogen-induced changes in rat mammary tumour oxygenation reported by near infrared spectroscopy

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    We have evaluated the ability of steady-state, radially-resolved, broad-band near infrared diffuse reflectance spectroscopy to measure carbogen-induced changes in haemoglobin oxygen saturation (SO2) and total haemoglobin concentration in a rat R3230 mammary adenocarcinoma model in vivo. Detectable shifts toward higher saturations were evident in all tumours (n = 16) immediately after the onset of carbogen breathing. The SO2 reached a new equilibrium within 1 min and remained approximately constant during 200–300 s of administration. The return to baseline saturation was more gradual when carbogen delivery was stopped. The degree to which carbogen increased SO2 was variable among tumours, with a tendency for tumours with lower initial SO2 to exhibit larger changes. Tumour haemoglobin concentrations at the time of peak enhancement were also variable. In the majority of cases, haemoglobin concentration decreased in response to carbogen, indicating that increased tumour blood volume was not responsible for the observed elevation in SO2. We observed no apparent relationship between the extent of the change in tumour haemoglobin concentration and the magnitude of the change in the saturation. Near infrared diffuse reflectance spectroscopy provides a rapid, non-invasive means of monitoring spatially averaged changes in tumour haemoglobin oxygen saturation induced by oxygen modifiers. © 1999 Cancer Research Campaig

    Frequency and risk factors of anthracycline-induced clinical heart failure in children: a systematic review

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    Background: Anthracyclines are essential for the treatment of the children with cancer. We performed a systematic review to evaluate the existing evidence of the frequency and risk factors of anthracycline-induced clinical heart failure (A-CHF) in children. Design: Medline was searched for articles reporting the frequency of A-CHF, published from 1966 to December 2000. Information about study features, risk factors and frequency were abstracted, and a validity score was given for each study. The potential predictive factors of A-CHF were analysed both within and across the studies. Results: The frequency of A-CHF in children was estimated in 30 studies described in 25 articles. All studies have serious methodological limitations. The frequency varied between 0% and 16%. In the analysis across the studies the type of anthracyclines and the maximal dose in 1 week explain a considerable part of the variation of the frequency of A-CHF. Conclusions: Doxorubicin and a dose above 45 mg/m(2) within 1 week seemed to increase the frequency of A-CHF. Well designed and executed studies are needed to accurately estimate the frequency of A-CHF and reliably assess the importance of potential risk factor

    Anthracycline-induced clinical heart failure in a cohort of 607 children: long-term follow-up study

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    PURPOSE: To determine the early and late cumulative incidence of anthracycline-induced clinical heart failure (A-CHF) after anthracycline therapy in childhood and to identify associated risk factors. PATIENTS AND METHODS: The cumulative incidence of A-CHF and the risk factors of A-CHF were assessed in a cohort of 607 children who had been treated with anthracyclines between 1976 and 1996. For 96% of the cohort, we obtained the clinical status up to at least January 1997. The mean follow-up time was 6.3 years. RESULTS: The cumulative incidence of A-CHF was 2.8%, after a mean follow-up time of 6.3 years and a mean cumulative dose of anthracyclines of 301 mg/m(2). A cumulative dose of anthracycline higher than 300 mg/m(2) was associated with an increased risk of A-CHF (relative risk, 11.8; 95% confidence interval, 1.6 to 59.5) compared with a cumulative dose lower than 300 mg/m(2). The estimated risk of A-CHF increased with time after the start of anthracycline chemotherapy to 2% after 2 years and 5% after 15 years. CONCLUSION: Up to 5% of patients will develop A-CHF 15 years after treatment, and patients treated with a cumulative dose of anthracyclines higher than 300 mg/m(2) are at highest risk for A-CHF. This is thus a considerable and serious problem among these young patients. The findings reinforce the need for strategies for early detection of patients at risk for A-CHF and for the evaluation of other chemotherapeutic possibilities or cardioprotective agents in relation to the surviva

    Frequency and risk factors of subclinical cardiotoxicity after anthracycline therapy in children: a systematic review

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    Background: The aim of this systematic review was to summarise and appraise the published evidence with regard to the frequency and risk factors of subclinical cardiotoxicity in apparently healthy survivors of childhood cancer after anthracycline therapy. Patients and methods: A search was made in Medline for studies published between 1966 and May 2001 that included >50 children and reported on the frequency of measures of subclinical cardiotoxicity. Information about the studies was abstracted by two reviewers and a validity score was calculated for each study. Results: The reported frequency of subclinical cardiotoxicity varied between 0% and 57% in the 25 studies included. Differences in outcome definitions of subclinical cardiotoxicity and differences in study patients with respect to the dose of anthracycline seemed to explain part of the wide variance of the frequency of subclinical cardiotoxicity. Fourteen of the 25 studies showed serious methodological limitations. Conclusions: The reported frequency of subclinical cardiotoxicity shows a wide variation. Well designed studies with accurate and precise outcome measurements in well described groups of patients, after a sufficiently long follow-up period, are needed to obtain more insight into the frequency and importance of risk factors, and the clinical consequences of anthracycline-related subclinical cardiotoxicit

    Microsatellite instability in childhood rhabdomyosarcoma is locus specific and correlates with fractional allelic loss.

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    Replication errors (RERs) were initially identified in hereditary nonpolyposis colon cancer and other tumors of Lynch syndrome II. Mutations in genes involved in mismatch repair give rise to a mutator phenotype, resulting in RERs. The mutator phenotype is thought to predispose to malignant transformation. Here we show that in the embryonal form of childhood rhabdomyosarcoma, RERs also occur, but in contrast to hereditary nonpolyposis colon cancer, only a subset of the microsatellite loci analyzed show RERs. The occurrence of RERs is strongly correlated with increased fractional allelic loss (P < 0.001), suggesting that the occurrence of RERs is a secondary phenomenon in rhabdomyosarcoma. Coincidental loss of genes involved in mismatch repair, possibly due to their proximity to tumor suppressor genes involved in tumor progression of embryonal form of childhood rhabdomyosarcoma, could explain the observed phenomenon
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