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Thomas Arn Hansen Helena Fridholm Tobias Guldberg Fr?slev Kristín Rós Kjartansdóttir Eske Willerslev Lars Peter Nielsen Anders Johannes Hansen 《PloS one》2015,10(11)
Rattus norvegicus (R. norvegicus) are ubiquitous and their presence has several effects on the human populations in our urban areas on a global scale. Both historically and presently, this close interaction has facilitated the dissemination of many pathogens to humans, making screening for potentially zoonotic and emerging viruses in rats highly relevant. We have investigated faecal samples from R. norvegicus collected from urban areas using a protocol based on metagenomic enrichment of circular DNA genomes and subsequent sequencing. We found a new type of papillomavirus, with a L1 region 82% identical to that of the known R. norvegicus Papillomavirus 2. Additionally, we found 20 different circular replication associated protein (Rep)-encoding single stranded DNA (CRESS-DNA) virus-like genomes, one of which has homology to the replication-associated gene of Beak and feather disease virus. Papillomaviruses are a group of viruses known for their carcinogenic potential, and although they are known to infect several different vertebrates, they are mainly studied and characterised in humans. CRESS-DNA viruses are found in many different environments and tissue types. Both papillomaviruses and CRESS-DNA viruses are known to have pathogenic potential and screening for novel and known viruses in R. norvegicus could help identify viruses with pathogenic potential. 相似文献
3.
A new instrument for environmental monitoring, called at 1-Hz fluorometer, provides two modes of application. First, it enables
a quantitative determination of algal concentrations down to 20 ng/l. Second, it can be used as a biosensor for changes in
environmental conditions. The distinction between the signals from living chlorophyll-containing algae and other fluorescent
material is achieved by using two modulated light-sources resulting in a mean fluence rate of 200 μE. The measuring light
induces changes in chlorophyll fluorescence (yield) with a frequency of 1 kHz, and the actinic light modulates the redox state
of the quenchers of PS II with a frequency of 1 Hz. This leads to a modulation of the yield which is detected by two phase-sensitive
rectifiers (double correlation). Measurements from different sites in a river, and in the Baltic and North Seas, show that
correction by the built-in simultaneously-measured attenuation is necessary in order to obtain values which are identical
with those determined by a photometric analysis (Uvikon 860). This applies if the transmission becomes less than about 95%.
Suspensions ofDunaliella salina exposed to ammonia and phosphate were used for illustrating the usage for environmental monitoring. It is shown that this
system can measure changes in the chlorophyll fluorescence of living algae caused by changes in concentration of ammonia down
to 1 μg/l and of phosphate down to 10 μg/l. 相似文献
4.
Stephan J. Linke Andreas Frings Ling Ren Amadeus Gomolka Udo Schumacher Rudolph Reimer Nils-Owe Hansen Nathan Jowett Gisbert Richard R. J. Dwayne Miller 《PloS one》2015,10(3)
The impact of using a Femtosecond laser on final functional results of penetrating keratoplasty is low. The corneal incisions presented here result from laser ablations with ultrafast desorption by impulsive vibrational excitation (DIVE). The results of the current study are based on the first proof-of-principle experiments using a mobile, newly introduced picosecond infrared laser system, and indicate that wavelengths in the mid-infrared range centered at 3 μm are efficient for obtaining applanation-free deep cuts on porcine corneas. 相似文献
5.
Christoph Plieth Burkhard Sattelmacher Ulf-Peter Hansen Marc R. Knight 《The Plant journal : for cell and molecular biology》1999,18(6):643-650
Aluminium, the most abundant metal in the earth's crust, is highly toxic to most plant species. One of the prevailing dogmas is that aluminium exerts this effect by disrupting cellular calcium homeostasis. However, recent research gives strongly conflicting results: aluminium was shown to provoke either an increase or a decrease in cytosolic free calcium concentration ([Ca2+]c). To solve this question, we have adopted a novel approach: [Ca2+]c measurements in intact plant roots as opposed to isolated cells, and the correlative measurements of intracellular and external pH. The results obtained show that plant roots respond to low external pH by a sustained elevation in [Ca2+]c. In the presence of aluminium, this pH-mediated elevation in [Ca2+]c does not occur, therefore any potential calcium-mediated protection against low pH is likely to be irreversibly inhibited. The severity of the inhibitory effect of aluminium on [Ca2+]c depends on the concentration of external calcium, thus perhaps explaining why the effects of aluminium toxicity are ameliorated in calcium-rich soils. It seems possible that a primary toxic effect of aluminium might be to impair calcium-mediated plant defence responses against low pH. 相似文献
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Kirsten Skamstrup Hansen Stefan Vieths Helle Vestergaard Per Stahl Skov Carsten Bindslev-Jensen Lars K. Poulsen 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2001,756(1-2)
The aim of the study was to investigate the possibility of a seasonal variation in reactivity to apples in 27 birch pollen allergic patients. Before and during the birch pollen season 1998, the patients were subjected to double-blind, placebo-controlled food challenges (DBPCFCs) with grated fresh Golden Delicious apple followed by an open food challenge with whole fresh apple. The clinical reactions elicited during the challenges were evaluated both by the patients and the investigators. Moreover, the skin reactivity and the in vitro reactivity to apple were evaluated by skin prick test (SPT), leukocyte histamine release (HR), measurement of specific IgE, and immunoblotting experiments. The sensitivity of the DBPCFC, when compared with the result of the open challenge, was 0.74 (14/19) before the season and 0.80 (16/20) during the season. None of the patients reacted to the blinded challenge without a subsequent reaction to the open challenge. One placebo reaction was registered both before and in season, but not in the same patient. The patient scores of the first positive challenges, and the maximal scores of each combined blinded and open challenge session, were significantly increased during the pollen season (P<0.05). The scores of the open challenge were significantly higher than the scores of the DBPCFC both before the season and during the in-season challenges (P<0.05). Specific IgE against Golden Delicious increased during season (P<0.05), while neither SPT, HR, nor immunoblotting experiments could confirm an increase in reactivity. In conclusion, the results of the oral challenge tests indicated an increase in clinical reactivity to apples during the birch pollen season in birch pollen allergic individuals. 相似文献
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V E Hjortdal E S Hansen D Kj?lseth T B Henriksen F Gottrup J C Djurhuus 《Plastic and reconstructive surgery》1991,87(2):326-334
In eight pigs, total blood flow, regional capillary blood flow distribution, and arteriovenous (AV) shunting were studied during the first 4 postoperative hours after elevation of a myocutaneous rectus abdominis island flap. Capillary blood flow and AV shunting were measured using radioactive microspheres before flap creation and 1 and 4 hours after surgery. Total blood flow, measured continuously as venous outflow, increased in the first postoperative hour (p less than 0.05). Elevation of the flap caused a slight decrease in skin capillary blood flow (p less than 0.05), whereas muscular capillary blood flow increased (p less than 0.01). AV shunting accounted for 50 percent of the total flap blood flow, whereas it was negligible in the abdominal wall prior to flap elevation. Thus stalk blood flow, skin appearance, and skin temperature may be poor indicators of nutritional capillary perfusion. However, the clinical and nutritional consequences of these findings remain to be established. 相似文献