168 research outputs found

    Analysis of Wireless Power System Efficiency in Dependency on Configuration of Resonant Tank

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    This chapter compares various compensation methods for resonant coupling of the wireless energy transfer system. A proposed analysis is particularly relevant to any application where contactless battery charging is used. Main parameters that are investigated include efficiency and electrical variables (current and voltage) of the circuit. In order to analyze the most suitable solution of coupling compensation, the relevant equations are graphically interpreted for each discussed circuit topology. Finally, this chapter provides the recommendations how to design the wireless power-transfer system with the highest possible efficiency for the given system parameters (switching frequency and transmitting distance)

    Treatment of metastatic head and neck cancer with mesenchymal stem cells combined with prodrug gene therapy

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    This is a clinical observation of a patient treated for metastatic head and neck cancer with mesenchymal stem cells mediated prodrug gene therapy. The cells were applied intravenously. We did not observe any therapeutic effect. However, a temporal bicytopenia was observed. Key Words: metastatic head and neck cancer, therapeutic stem cells, blood counts

    Phylogeographic perspective on the distribution and dispersal of a marine pathogen, the oyster parasite Bonamia exitiosa

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    The significance of infectious disease has intensified as our marine ecosystems are increasingly altered, with molluscan taxa being among the affected. One of the important pathogens to emerge in recent years, the oyster parasite Bonamia exitiosa,has a broad geographic distribution and has been found to infect a number of oyster species. In order to better understand how B. exitiosa achieved this wide distribution, a gene genealogy was constructed using internal transcribed spacer region ribosomal DNA sequencing data from across the host species range.The analysis revealed population structure in the form of 4 well-defined groups of sequences: 3corresponding to geographic regions (temperate Atlantic and Pacific waters of the Southern Hemisphere, California, and the western Atlantic along the coast of the Americas) and the fourth geographically cosmopolitan. Inclusion of B. exitiosa sequences from New Zealand, Australia, and Argentina in the Southern Hemisphere group may reflect natural dispersal of the parasite via raft-ing with oyster hosts, whereas the California group may reflect limited anthropogenic movement of a host species, Ostrea lurida. The extensive geographic distribution of B. exitiosa parasites belonging to the cosmopolitan and Atlantic Coast groups may relate to both natural and anthropogenic dispersal of a single host, O. stentina, which is distributed from the eastern Americas tothe Mediterranean and African coast to New Zealand — that is, in most regions where B. exitiosa has been found to occur

    Bacteremias caused by Escherichia coli in cancer patients — analysis of 65 episodes

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    AbstractObjectives: The aims of this study were to evaluate risk factors, clinical presentation, outcome and antimicrobial susceptibility in patients with Escherichia coli bacteremia occurring over seven years in a single cancer hospital.Methods: Sixty five episodes of bacteremia from E. coli appearing over seven years from 12,301 admissions in a single cancer institution were retrospectively analyzed.Results: The proportion of bacteremia caused by E. coli among Gram-negative bacteremia was 20.8% (the second most common organism after Pseudomonas aeruginosa), and infection-associated mortality was 17%.The incidence in 1989–1995 varied from 14.3 to 24.7%. The most common risk factors were: solid tumors as the underlying disease (70.7%); central venous catheter insertion (32.3%); prior surgery (46.2%), and prior chemotherapy within 48 h (44.4%). Neutropenia and urinary catheters did not place patients at high risk in any of the subgroups. When we compared the two subgroups of 61 cases of bacteremia — monomicrobial and polymicrobial (when E. coli was isolated from blood culture with another microorganism) — we found that acute leukemia and breakthrough (recurrence while receiving antibiotics) bacteremia were more frequently associated with polymicrobial E. coli bacteremia. There was also a difference in infection-associated mortality: monomicrobial bacteremia due to E. coli only had a significantly lower mortality in comparison with polymicrobial E. coli bacteremia (8.9 vs 35.0%, respectively; P<0.03).Conclusion: The susceptibility of 115 E. coli strains isolated from 65 episodes of bacteremia was stable. Only two episodes caused by quinolone-resistant strains occurred, both in 1995, after six years of using ofloxacin for prophylaxis in neutropenic patients in our hospital. We found that 85.2–91.3% of all strains were susceptible to aminoglycosides, 97.8% to quinolones, and 90–100% to third generation cephalosporins and imipenems.The patients most commonly infected had solid tumors and the mortality was only 17%

    Light pulsed irradiation in growing seedlings

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    This work presents the research results of dynamic characteristics of ARPL-1W LEDs with a narrow-spectrum composition of luminescence (red, green, blue) using switching power supply of U-shaped pulses. Based on the results of increase and decrease of light flux and analysis of the kinetics of photosynthetic processes, from light absorption to absorption of CO2 from the atmosphere and the formation of carbohydrates, the LED irradiation installation is designed and approbated for growing seedlings. According to the results of experimental studies it is shown that pulsed irradiation stimulates faster plant growth without losing their morphometric parameters

    Parasites of Moroccan desert Coptodon guineensis (Pisces, Cichlidae): transition and resilience in a simplified hypersaline ecosystem

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    Sebkha Imlili (Atlantic Sahara) is a salt flat with over 160 permanent holes of hypersaline water generated in the Holocene and inhabited by euryhaline organisms that are considered to be relics of the past, including the cichlid fish Coptodon guineensis. We surveyed the fish parasites four times over one year, to i) identify the parasites, and ii) determine possible seasonality in infection patterns. Over 60% of the fish were infected by one to three helminths: an acanthocephalan in the intestine and two digenean metacercariae in the kidney, spleen, liver, muscle, and mesenteries. The acanthocephalan Acanthogyrus (Acanthosentis) cf. tilapiae was identified morphologically and molecularly; only one digenean (the heterophyid Pygidiopsis genata) could be identified molecularly. Both identified parasites were present throughout the sampling periods; the unidentified metacercariae were present only in summer and fall. Mean intensities, but not prevalence of infection by the acanthocephalan, reflected a biannual pattern of transmission. Infection accrued with fish size, possibly due to cannibalism. Because the water holes include only a few invertebrates, the intermediate hosts of these parasites can be inferred to be the gastropod Ecrobia ventrosa for the digeneans and either the copepod Cletocamtpus retrogressus or the ostracod Cyprideis torosa for the acanthocephalan. This ecosystem appears stable and provides a window into the past, as the acanthocephalan likely switched from freshwater tilapia to C. guineensis when the Sebkha formed. However, this is a vulnerable environment where the survival of these parasites depends on interactions maintained among only very few hosts

    Integrated motor drives: state of the art and future trends

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    With increased need for high power density, high efficiency and high temperature capabilities in Aerospace and Automotive applications, Integrated Motor Drives (IMD) offers a potential solution. However, close physical integration of the converter and the machine may also lead to an increase in components temperature. This requires careful mechanical, structural and thermal analysis; and design of the IMD system. This paper reviews existing IMD technologies and their thermal effects on the IMD system. The effects of the power electronics (PE) position on the IMD system and its respective thermal management concepts are also investigated. The challenges faced in designing and manufacturing of an IMD along with the mechanical and structural impacts of close physical integration is also discussed and potential solutions are provided. Potential converter topologies for an IMD like the Matrix converter, 2-level Bridge, 3-level NPC and Multiphase full bridge converters are also reviewed. Wide band gap devices like SiC and GaN and their packaging in power modules for IMDs are also discussed. Power modules components and packaging technologies are also presented
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