3,743 research outputs found
Long-term carriage, and transmission of methicillin-resistant Staphylococcus aureus after discharge from hospital
The purpose of this study was to determine whether patients who become carriers of methicillin-resistant Staphylococcus aureus (MRSA) during their stay in hospital, remain colonized after discharge. Thirty-six patients colonized with MRSA during one of three outbreaks at Utrecht University Hospital (1986-89) were screened 2 or 3 years after they had become carriers. Patients were also interviewed to determine factors contributing to persistent carriage, such as antibiotics, re-admissions to the hospital, presence of skin lesions and chronic diseases. At the same time transmission of MRSA to family members was determined. The epidemic MRSA strain was still found in three patients (8%). One was a cystic fibrosis patient who had had frequent re-admissions to the hospital and had received several course of antibiotic treatment. Both of the other patients had skin lesions: a fistula and a colostomy respectively. None of the 44 family members of the patients was colonized or infected with MRSA. We conclude that long-term MRSA carriage occurs with low frequency and is comparable to persistent carriage of methicillin-sensitive Staphylococcus aureus (MSSA). Transmission of MRSA to healthy individuals in an antibiotic-free environment is a rare event
Chitinozoan biozonation in the upper Katian and Hirnantian of the Welsh Basin, UK
AbstractHere we present a chitinozoan biostratigraphical framework for the South Wales upper Katian and Hirnantian (Ashgill) succession. The current study indicates that three of the six Avalonian Ashgill chitinozoan biozones are recognised in the Welsh Basin; the bergstroemi, fossensis and umbilicata biozones. The Baltoscandian and Laurentian Hercochitina gamachiana biozone is suggested by the presence of Belonechitina cf. gamachiana and the Spinachitina taugourdeaui biozone is suggested by Spinachitina cf. taugourdeaui. Intervening between these is a newly erected lower Hirnantian regional biozone, the Belonechitina llangrannogensis n. sp. biozone. The late Katian (Cautleyan–Rawtheyan) Conochitina rugata biozone was not recognised, though the index taxon is recorded. The presence of B. cf. gamachiana below the lithological expression of the Hirnantian glacial maximum and alongside Rawtheyan graptolite and trilobite assemblages shows that the local base of the B. cf. gamachiana biozone lies beneath the Katian–Hirnantian boundary. Although at present in open nomenclature, the finds of B. cf. gamachiana and S. cf. taugourdeaui, from sites where these chitinozoans co-occur with graptolites, are potentially important; the area offers the potential to study how B. cf. gamachiana and S. cf. taugourdeaui are taxonomically and stratigraphically linked to the original index species. A composite Katian–Hirnantian chitinozoan biozonation for the Welsh Basin is presented and three new species are defined: Belonechitina llangrannogensis n. sp., Belonechitina ceregidionensis n. sp. and Spinachitina penbryniensis n. sp
TARGET: toward a solution for the readout electronics of the Cherenkov Telescope Array
TARGET is an application specific integrated circuit (ASIC) designed to read
out signals recorded by the photosensors in cameras of very-high-energy
gamma-ray telescopes exploiting the imaging of Cherenkov radiation from
atmospheric showers. TARGET capabilities include sampling at a high rate
(typically 1 GSample/s), digitization, and triggering on the sum of four
adjacent pixels. The small size, large number of channels read out per ASIC
(16), low cost per channel, and deep buffer for trigger latency (~16 s at
1 GSample/s) make TARGET ideally suited for the readout in systems with a large
number of telescopes instrumented with compact photosensors like multi-anode or
silicon photomultipliers combined with dual-mirror optics. The possible
advantages of such systems are better sensitivity, a larger field of view, and
improved angular resolution. The two latest generations of TARGET ASICs, TARGET
5 and TARGET 7, are soon to be used for the first time in two prototypes of
small-sized and medium-sized dual-mirror telescopes proposed in the framework
of the Cherenkov Telescope Array (CTA) project. In this contribution we report
on the performance of the TARGET ASICs and discuss future developments.Comment: 8 pages, 3 figures. In Proceedings of the 34th International Cosmic
Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions
at arXiv:1508.0589
Development of a SiPM Camera for a Schwarzschild-Couder Cherenkov Telescope for the Cherenkov Telescope Array
We present the development of a novel 11328 pixel silicon photomultiplier
(SiPM) camera for use with a ground-based Cherenkov telescope with
Schwarzschild-Couder optics as a possible medium-sized telescope for the
Cherenkov Telescope Array (CTA). The finely pixelated camera samples air-shower
images with more than twice the optical resolution of cameras that are used in
current Cherenkov telescopes. Advantages of the higher resolution will be a
better event reconstruction yielding improved background suppression and
angular resolution of the reconstructed gamma-ray events, which is crucial in
morphology studies of, for example, Galactic particle accelerators and the
search for gamma-ray halos around extragalactic sources. Packing such a large
number of pixels into an area of only half a square meter and having a fast
readout directly attached to the back of the sensors is a challenging task. For
the prototype camera development, SiPMs from Hamamatsu with through silicon via
(TSV) technology are used. We give a status report of the camera design and
highlight a number of technological advancements that made this development
possible.Comment: 8 pages, 5 figures, In Proceedings of the 34th International Cosmic
Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions
at arXiv:1508.0589
Роль международной мобильности ученых на разных этапах истории науки Украины
В статье освещается эволюция международного сотрудничества ученых Украины с зарубежными исследователями. Продемонстрировано огромное влияние стажировки отечественных ученых в крупнейших научных центрах мира, совместных исследований с зарубежными исследователями для становления науки в Украине, развития сети научных учреждений и высших учебных заведений. Охарактеризовано основные тенденции международного сотрудничества ученых Национальной академии наук и миграции научных работников в последние десятилетия.У статті висвітлюється еволюція міжнародного співробітництва вчених України з зарубіжними дослідниками. Продемонстровано величезний вплив стажування вітчизняних учених у найбільших наукових центрах світу, спільних досліджень із зарубіжними дослідниками для становлення науки в Україні, розвитку мережі наукових установ та вищих навчальних закладів. Охарактеризовано основні тенденції міжнародної співпраці вчених Національної академії наук України та міграції наукових працівників в останні десятиліття.Evolution of the international cooperation of Ukrainian scientists with foreign researchers is emphasized. The great impact from probation of national scientists at largest research centers across the globe, joint research with foreign partners on establishing the science system in Ukraine and building up the network of research institutions and higher education establishments is shown. Main tendencies in the international cooperation of scientists from the National Academy of Sciences of Ukraine and scientists’ migration in the latest decades
Matrix metalloproteinase 13 modulates intestinal epithelial barrier integrity in inflammatory diseases by activating TNF
Several pathological processes, such as sepsis and inflammatory bowel disease (IBD), are associated with impairment of intestinal epithelial barrier. Here, we investigated the role of matrix metalloproteinase MMP13 in these diseases. We observed that MMP13(-/-) mice display a strong protection in LPS- and caecal ligation and puncture-induced sepsis. We could attribute this protection to reduced LPS-induced goblet cell depletion, endoplasmic reticulum stress, permeability and tight junction destabilization in the gut of MMP13(-/-) mice compared to MMP13(+/+) mice. Both in vitro and in vivo, we found that MMP13 is able to cleave pro-TNF into bioactive TNF. By LC-MS/MS, we identified three MMP13 cleavage sites, which proves that MMP13 is an alternative TNF sheddase next to the TNF converting enzyme TACE. Similarly, we found that the same mechanism was responsible for the observed protection of the MMP13(-/-) mice in a mouse model of DSS-induced colitis. We identified MMP13 as an important mediator in sepsis and IBD via the shedding of TNF. Hence, we propose MMP13 as a novel drug target for diseases in which damage to the gut is essential
The PANDA GEM-based TPC Prototype
We report on the development of a GEM-based TPC prototype for the PANDA
experiment. The design and requirements of this device will be illustrated,
with particular emphasis on the properties of the recently tested GEM-detector,
the characterization of the read-out electronics and the development of the
tracking software that allows to evaluate the GEM-TPC data.Comment: submitted to NIMA 4 pages, 6 picture
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