646 research outputs found

    Sedimentary Iron Cycling and the Origin and Preservation of Magnetization in Platform Carbonate Muds, Andros Island, Bahamas

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    Carbonate muds deposited on continental shelves are abundant and well-preserved throughout the geologic record because shelf strata are difficult to subduct and peritidal carbonate units often form thick, rheologically strong units that resist penetrative deformation. Much of what we know about pre-Mesozoic ocean chemistry, carbon cycling, and global change is derived from isotope and trace element geochemistry of platform carbonates. Paleomagnetic data from the same sediments would be invaluable, placing records of paleolatitude, paleogeography, and perturbations to the geomagnetic field in the context and relative chronology of chemostratigraphy. To investigate the depositional and early diagenetic processes that contribute to magneitzation in carbonates, we surveyed over 500 core and surface samples of peritidal, often microbially bound carbonate muds spanning the last not, vert, similar 1000 yr and deposited on top of Pleistocene aeolianites in the Triple Goose Creek region of northwest Andros Island, Bahamas. Sedimentological, geochemical, magnetic and ferromagnetic resonance properties divide the sediment columns into three biogeochemical zones. In the upper sediments, the dominant magnetic mineral is magnetite, produced by magnetotactic bacteria and dissimiliatory microbial iron metabolism. At lower depths, above or near mean tide level, microbial iron reduction dissolves most of the magnetic particles in the sediment. In some cores, magnetic iron sulfides precipitate in a bottom zone of sulfate reduction, likely coupled to the oxidation of decaying mangrove roots. The remanent magnetization preserved in all oriented samples appears indistinguishable from the modern local geomagnetic field, which reflects the post-depositional origin of magnetic particles in the lower zone of the parasequence. While we cannot comment on the effects of late-stage diagenesis or metamorphism on remanence in carbonates, we postulate that early-cemented, thin-laminated parasequence tops in ancient peritidal carbonates are mostly likely to preserve syn-depositional paleomagnetic directions and magnetofossil stratigraphies

    The survival rate of hepatocellular carcinoma in asian countries: A systematic review and meta-analysis

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    Hepatocellular carcinoma or Liver cancer (LC) is the sixth most common cancer and the fourth cause of death worldwide in 2018. There has not been a comprehensive study on the survival rate of patients with LC in Asia yet. Therefore, the present study was conducted to evaluate the survival rate of patients with LC in Asian countries. The methodology of the present study is based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) statement. The researchers searched five international databases including Medline/PubMed, Scopus, Embase, Web of Knowledge and ProQuest until July 1, 2018. We also searched Google Scholar for detecting grey literature. The Newcastle-Ottawa Quality Assessment Form was used to evaluate the quality of selected papers. A total of 1425 titles were retrieved. 63 studies met the inclusion criteria. Based on the random-effect model one-year, three-year and five-year survival rate of LC were 34.8 (95 CI; 30.3-39.3), 19 (95 CI; 18.2-21.8) and 18.1 (95 CI;16.1-20.1) respectively. According to the results of our study, the LC survival rate in Asian countries is relatively lower than in Europe and North America. © 2020, Leibniz Research Centre for Working Environment and Human Factors. All rights reserved

    A survey on the radiation protection status among radiology staff

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    Introduction: Radiation exposure during radiological examination is a health concern, of which radiology professionals should be cognizant. We sought to evaluate the radiation protection knowledge, attitudes, and practice (KAP) amongst radiology staff of hospitals across 10 provinces of Iran. Materials and Methods: For evaluating the level of radiation protection KAP, 553 radiology staff were enrolled. A 32-item questionnaire was designed to assess radiation protection KAP, the validity which was confirmed by members of the Medical Physics and Biostatistics departments. The questionnaire evaluated the respondents' knowledge, practice, and attitudes towards the basic principles of radiation protection, the necessity of using protective equipment, and their performance in the implementation of radiation protection recommendations. Results: We found no significant difference in the level of radiation protection KAP between male and female radiology staff and among those with different educational levels and ages (P > 0.05). However, there was a significant association between radiation protection KAP and working experience, hospital size, and hospital type (P 0.05). Conclusion: Our results showed that the level of radiation protection KAP among radiology staff is inadequate. This might be due to the lack of ongoing training courses concerning protection against ionizing radiation. Thus, sustained training of radiation protection principles can promote KAP among the staff of radiology departments, and in turn, reduce public dose from medical diagnostic modalities. © 2018, Mashhad University of Medical Sciences

    Effect of Satureja hortensis extracted oil on Aspergillus flavusin fish feed

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    In a preliminary study, the antifungal properties of essential oil of Satureja hortensis at different tenderness were tested on potato – dextrose agar (PDA). The fungus Aspergillus flavus PTCC 5006 was isolated from pistachio nut obtained from Rafsanjan area, Iran. Among the essential oil compounds, 500 ppm concentration was completely inhibited Aspergillus flavus growth. After determination of the most effective concentration, it was added to fish feeds compound which inhibited fungal growth and production of aflatoxin. Its concentration was determined as 500 ppm and over of essential oil of Satureja hortensis. The essential oil of Satureja hortensis was analyzed by means of GC-MS and their effective factors were evaluated for fish feeds and their results are shown in tables

    Graft calcifications and dysfunction following liver transplantation

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    BACKGROUND: The molecular events, following ischemia and reperfusion (I/R) of the liver during transplantation are largely unknown. There is evidence that apoptotic and necrotic events may take place, and occasionally result in primary graft dysfunction. We herein report two cases, where significant I/R injury correlated with the development of liver calcification and primary liver dysfunction. CASE PRESENTATION: Both patients with clinical and biochemical evidence of primary graft dysfunction demonstrated calcification at light and electron microscopy levels. In addition, one patient had macroscopic evidence of calcification on cross-sectional imaging. Both patients died secondary to the sequelae of the graft dysfunction. CONCLUSIONS: Severe I/R-induced injury to the liver, clinically leads to graft dysfunction. This is due to advanced apoptotic and/or necrotic events at the hepatocyte level that may, on the most severe form, lead to calcification. The study of microcalcification at the early posttransplant period could provide insight in the events taking place following significant ischemia/reperfusion-induced injury to the graft

    The relativistic Sagnac Effect: two derivations

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    The phase shift due to the Sagnac Effect, for relativistic matter and electromagnetic beams, counter-propagating in a rotating interferometer, is deduced using two different approaches. From one hand, we show that the relativistic law of velocity addition leads to the well known Sagnac time difference, which is the same independently of the physical nature of the interfering beams, evidencing in this way the universality of the effect. Another derivation is based on a formal analogy with the phase shift induced by the magnetic potential for charged particles travelling in a region where a constant vector potential is present: this is the so called Aharonov-Bohm effect. Both derivations are carried out in a fully relativistic context, using a suitable 1+3 splitting that allows us to recognize and define the space where electromagnetic and matter waves propagate: this is an extended 3-space, which we call "relative space". It is recognized as the only space having an actual physical meaning from an operational point of view, and it is identified as the 'physical space of the rotating platform': the geometry of this space turns out to be non Euclidean, according to Einstein's early intuition.Comment: 49 pages, LaTeX, 3 EPS figures. Revised (final) version, minor corrections; to appear in "Relativity in Rotating Frames", ed. G. Rizzi and M.L. Ruggiero, Kluwer Academic Publishers, Dordrecht, (2003). See also http://digilander.libero.it/solciclo

    European Council of Legal Medicine (ECLM) on-site inspection forms for forensic pathology, anthropology, odontology, genetics, entomology and toxicology for forensic and medico-legal scene and corpse investigation: the Parma form

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    Further to a previous publication by the European Council of Legal Medicine (ECLM) concerning on-site forensic and medico-legal scene and corpse investigation, this publication provides guidance for forensic medical specialists, pathologists and, where present, coroners’ activity at a scene of death inspection and to harmonize the procedures for a correct search, detection, collection, sampling and storage of all elements which may be useful as evidence, and ensure documentation of all these steps. This ECLM’s inspection form provides a checklist to be used on-site for the investigation of a corpse present at a crime or suspicious death scene. It permits the collection of all relevant data not only for the pathologist, but also for forensic anthropologists, odontologists, geneticists, entomologists and toxicologists, thus supporting a collaborative work approach. Detailed instructions for the completion of forms are provided

    Cost-Effectiveness of Preoperative Screening and Eradication of Staphylococcus aureus Carriage

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    BACKGROUND: Preoperative screening for nasal S. aureus carriage, followed by eradication treatment of identified carriers with nasal mupirocine ointment and chlorhexidine soap was highly effective in preventing deep-seated S. aureus infections. It is unknown how cost-effectiveness of this intervention is affected by suboptimal S. aureus screening. We determined cost-effectiveness of different preoperative S. aureus screening regimes. METHODS: We compared different screening scenarios (ranging from treating all patients without screening to treating only identified S. aureus carriers) to the base case scenario without any screening and treatment. Screening and treatment costs as well as costs and mortality due to deep-seated S. aureus infection were derived from hospital databases and prospectively collected data, respectively. RESULTS: As compared to the base case scenario, all scenarios are associated with improved health care outcomes at reduced costs. Treating all patients without screening is most cost-beneficial, saving €7339 per life year gained, as compared to €3330 when only identified carriers are treated. In sensitivity analysis, outcomes are susceptible to the sensitivity of the screening test and the efficacy of treatment. Reductions in these parameters would reduce the cost-effectiveness of scenarios in which treatment is based on screening. When only identified S. aureus carriers are treated costs of screening should be less than €6.23 to become the dominant strategy. CONCLUSIONS: Preoperative screening and eradication of S. aureus carriage to prevent deep-seated S. aureus infections saves both life years and medical costs at the same time, although treating all patients without screening is the dominant strategy, resulting in most health gains and largest savings
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