995 research outputs found
A Rare Case of Jejunal Arterio-Venous Fistula: Treatment with Superselective Catheter Embolization with a Tracker-18 Catheter and Microcoils
Arterio-venous fistulas may develop spontaneously, following trauma or infection, or be iatrogenic in nature. We present a rare case of a jejunal arterio- venous fistula in a 35-year-old man with a history of pancreatic head resection that had been performed two years previously because of chronic pancreatitis. The patient was admitted with acute upper abdominal pain, vomiting and an abdominal machinery-type bruit. The diagnosis of a jejunal arterio-venous fistula was established by MR imaging. Transfemoral angiography was performed to assess the possibility of catheter embolization. The angiographic study revealed a small aneurysm of the third jejunal artery, abnormal early filling of dilated jejunal veins and marked filling of the slightly dilated portal vein (13-14 mm). We considered the presence of segmental portal hypertension. The patient was treated with coil embolization in the same angiographic session. This case report demonstrates the importance of auscultation of the abdomen in the initial clinical examination. MR imaging and color Doppler ultrasound are excellent noninvasive tools in establishing the diagnosis. The role of interventional radiological techniques in the treatment of early portal hypertension secondary to jejunal arterio-venous fistula is discussed at a time when this condition is still asymptomatic. A review of the current literature is include
Redshift Evolution in the Iron Abundance of the Intracluster Medium
Clusters of galaxies provide a closed box within which one can determine the
chemical evolution of the gaseous baryons with cosmic time. We studied this
metallicity evolution in the hot X-ray emitting baryons through an analysis of
XMM-Newton observations of 29 galaxy clusters in the redshift range 0.3 < z <
1.3. Taken alone, this data set does not show evidence for significant
evolution. However, when we also include a comparable sample of 115 clusters
observed with Chandra (Maughan et al. 2008) and a lower redshift sample of 70
clusters observed with XMM at z < 0.3 (Snowden et al. 2008), there is
definitive evidence for a decrease in the metallicity. This decrease is
approximately a factor of two from z = 0 to z \approx 1, over which we find a
least-squares best-fit line Z(z) / Z_{\odot} = (0.46 \pm 0.05) - (0.38 \pm
0.03)z. The greatest uncertainty in the evolution comes from poorly constrained
metallicities in the highest redshift bin
Probiotics, prematurity and neurodevelopment: Follow-up of a randomised trial
Objective To determine the impact of one probiotics combination on the neurodevelopment of very preterm children at 2–5 years corrected gestational age (CA).
Design Follow-up study of survivors of a double-blinded, placebo-controlled, randomised trial of probiotic effects on late-onset sepsis in very preterm infants that found reduced necrotising enterocolitis. setting 10 tertiary perinatal centres in Australia and New Zealand. Patients 1099 very preterm infants born <32 weeks’ gestation and weighing <1500 g. Intervention Probiotics (Bifidobacterium infantis, Streptococcus thermophilus and Bifidobacterium lactis) or placebo administered from birth until discharge home or term CA, whichever came sooner.
Main outcome measures Major neurodevelopmental impairment comprised any of moderate/severe cerebral palsy (Gross Motor Function Classification System score 2–5), motor impairment (Bayley-III Motor Composite Scale <–2SD or Movement Assessment Battery for Children <15th centile if ≫42 months’ CA), cognitive impairment (Bayley-III Composite Cognitive or Language Scales <–2SD or Wechsler Preschool and Primary Scale of Intelligence Full Scale Intelligence Quotient <–2SD if ≫42 months’ CA), blindness or deafness.
Results Outcome data were available for 735 (67%) participants, with 71 deaths and 664/1028 survivors assessed at a mean age of 30 months. Survival free of major neurodevelopmental impairment was comparable between groups (probiotics 281 (75.3%) vs placebo 271 (74.9%); relative risk 1.01 (95% CI 0.93 to 1.09)). Rates of deafness were lower in probiotic-treated children (0.6% vs 3.4%).
Conclusion Administration of the probiotics combination Bifidobacterium infantis, Streptococcus thermophilus and Bifidobacterium lactis to very preterm babies from soon after birth until discharge home or term CA did not adversely affect neurodevelopment or behaviour in early childhood
Long-term perspectives on terrestrial and aquatic carbon cycling from palaeolimnology
Lakes are active processors and collectors of carbon (C) and thus recognized as quantitatively important within the terrestrial C cycle. Better integration of palaeolimnology (lake sediment core analyses) with limnological or modelling approaches has the potential to enhance understanding of lacustrine C processing and sequestration. Palaeolimnology simultaneously assimilates materials from across lake habitats, terrestrial watersheds and airsheds to provide a uniquely broad overview of the terrestrial-atmospheric-aquatic linkages across spatial scales. The examination of past changes over decadal-millenial timescales via palaeolimnology can inform understanding and prediction of future changes in C cycling. With a particular, but not exclusive, focus on northern latitudes we examine the methodological approaches of palaeolimnology, focusing on how relatively standard and well tested techniques might be applied to address questions of relevance to the C cycle. We consider how palaeolimnology, limnology and sedimentation studies might be linked to provide more quantitative and holistic estimates lake C cycling. Finally, we use palaeolimnological examples to consider how changes such as terrestrial vegetation cover, permafrost thaw, the formation of new lakes and reservoirs, hydrological modification of inorganic C processing, land use change, soil erosion and disruption to global nitrogen and phosphorus cycles might influence lake C cycling
Transgenic increases in seed oil content are associated with the differential expression of novel Brassica-specific transcripts
<p>Abstract</p> <p>Background</p> <p>Seed oil accumulates primarily as triacylglycerol (TAG). While the biochemical pathway for TAG biosynthesis is known, its regulation remains unclear. Previous research identified microsomal diacylglycerol acyltransferase 1 (DGAT1, EC 2.3.1.20) as controlling a rate-limiting step in the TAG biosynthesis pathway. Of note, overexpression of <it>DGAT1 </it>results in substantial increases in oil content and seed size. To further analyze the global consequences of manipulating <it>DGAT1 </it>levels during seed development, a concerted transcriptome and metabolome analysis of transgenic <it>B. napus </it>prototypes was performed.</p> <p>Results</p> <p>Using a targeted <it>Brassica </it>cDNA microarray, about 200 genes were differentially expressed in two independent transgenic lines analyzed. Interestingly, 24–33% of the targets showing significant changes have no matching gene in <it>Arabidopsis </it>although these represent only 5% of the targets on the microarray. Further analysis of some of these novel transcripts indicated that several are inducible by ABA in microspore-derived embryos. Of the 200 <it>Arabidopsis </it>genes implicated in lipid biology present on the microarray, 36 were found to be differentially regulated in DGAT transgenic lines. Furthermore, kinetic reverse transcriptase Polymerase Chain Reaction (k-PCR) analysis revealed up-regulation of genes encoding enzymes of the Kennedy pathway involved in assembly of TAGs. Hormone profiling indicated that levels of auxins and cytokinins varied between transgenic lines and untransformed controls, while differences in the pool sizes of ABA and catabolites were only observed at later stages of development.</p> <p>Conclusion</p> <p>Our results indicate that the increased TAG accumulation observed in transgenic <it>DGAT1 </it>plants is associated with modest transcriptional and hormonal changes during seed development that are not limited to the TAG biosynthesis pathway. These might be associated with feedback or feed-forward effects due to altered levels of DGAT1 activity. The fact that a large fraction of significant amplicons have no matching genes in <it>Arabidopsis </it>compromised our ability to draw concrete inferences from the data at this stage, but has led to the identification of novel genes of potential interest.</p
Mapping the Operation of the Miniature Combustion Aerosol Standard (Mini-CAST) Soot Generator
The Jing Ltd. miniature combustion aerosol standard (Mini- CAST) soot generator is a portable, commercially available burner that is widely used for laboratory measurements of soot processes. While many studies have used the Mini-CAST to generate soot with known size, concentration, and organic carbon fraction under a single or few conditions, there has been no systematic study of the burner operation over a wide range of operating conditions. Here, we present a comprehensive characterization of the microphysical, chemical, morphological, and hygroscopic properties of Mini- CAST soot over the full range of oxidation air and mixing N2 flow rates. Very fuel-rich and fuel-lean flame conditions are found to produce organic-dominated soot with mode diameters of 10–60 nm, and the highest particle number concentrations are produced under fuel-rich conditions. The lowest organic fraction and largest diameter soot (70–130 nm) occur under slightly fuel-lean conditions. Moving from fuel-rich to fuel-lean conditions also increases the O:C ratio of the soot coatings from ~0.05 to ~0.25, which causes a small fraction of the particles to act as cloud condensation nuclei near the Kelvin limit (κ ~ 0–10−3). Comparison of these property ranges to those reported in the literature for aircraft and diesel engine soots indicates that the Mini-CAST soot is similar to real-world primary soot particles, which lends itself to a variety of process-based soot studies. The trends in soot properties uncovered here will guide selection of burner operating conditions to achieve optimum soot properties that are most relevant to such studies
Two More Candidate AM Canum Venaticorum (AM CVn) Binaries from the Sloan Digital Sky Survey
AM CVn systems are a select group of ultracompact binaries with the shortest
orbital periods of any known binary subclass; mass-transfer is likely from a
low-mass (partially-)degenerate secondary onto a white dwarf primary, driven by
gravitational radiation. In the past few years, the Sloan Digital Sky Survey
(SDSS) has provided five new AM CVns. Here we report on two further candidates
selected from more recent SDSS data. SDSS J1208+3550 is similar to the earlier
SDSS discoveries, recognized as an AM CVn via its distinctive spectrum which is
dominated by helium emission. From the expanded SDSS Data Release 6 (DR6)
spectroscopic area, we provide an updated surface density estimate for such AM
CVns of order 10^{-3.1} to 10^{-2.5} per deg^2 for 15<g<20.5. In addition, we
present another new candidate AM CVn, SDSS J2047+0008, that was discovered in
the course of followup of SDSS-II supernova candidates. It shows nova-like
outbursts in multi-epoch imaging data; in contrast to the other SDSS AM CVn
discoveries, its (outburst) spectrum is dominated by helium absorption lines,
reminiscent of KL Dra and 2003aw. The variability selection of SDSS J2047+0008
from the 300 deg^2 of SDSS Stripe 82 presages further AM CVn discoveries in
future deep, multicolor, and time-domain surveys such as LSST. The new
additions bring the total SDSS yield to seven AM CVns thus far, a substantial
contribution to this rare subclass, versus the dozen previously known.Comment: 19 pages, 5 figures, 1 table; submitted to A
Cataclysmic Variables from SDSS II. The Second Year
The first full year of operation following the commissioning year of the
Sloan Digital Sky Survey has revealed a wide variety of newly discovered
cataclysmic variables. We show the SDSS spectra of forty-two cataclysmic
variables observed in 2002, of which thirty-five are new classifications, four
are known dwarf novae (CT Hya, RZ Leo, T Leo and BZ UMa), one is a known CV
identified from a previous quasar survey (Aqr1) and two are known ROSAT or
FIRST discovered CVs (RX J09445+0357, FIRST J102347.6+003841). The SDSS
positions, colors and spectra of all forty-two systems are presented. In
addition, the results of follow-up studies of several of these objects identify
the orbital periods, velocity curves and polarization that provide the system
geometry and accretion properties. While most of the SDSS discovered systems
are faint (>18th mag) with low accretion rates (as implied from their spectral
characteristics), there are also a few bright objects which may have escaped
previous surveys due to changes in the mass transfer rate.Comment: Accepted for publication in The Astronomical Journal, Vol. 126, Sep.
2003, 44 pages, 25 figures (now with adjacent captions), AASTeX v5.
Impacts of ambient air quality on acute asthma hospital admissions during the COVID-19 pandemic in Oxford City, UK:a time-series study
OBJECTIVES: The study aims to investigate the short-term associations between exposure to ambient air pollution (nitrogen dioxide (NO2), particulate matter pollution-particles with diameter<2.5 µm (PM2.5) and PM10) and incidence of asthma hospital admissions among adults, in Oxford, UK.DESIGN: Retrospective time-series study.SETTING: Oxford City (postcode areas OX1-OX4), UK.PARTICIPANTS: Adult population living within the postcode areas OX1-OX4 in Oxford, UK from 1 January 2015 to 31 December 2021.PRIMARY AND SECONDARY OUTCOME MEASURES: Hourly NO2, PM2.5 and PM10 concentrations and meteorological data for the period 1 January 2015 to 31 December 2020 were analysed and used as exposures. We used Poisson linear regression analysis to identify independent associations between air pollutant concentrations and asthma admissions rate among the adult study population, using both single (NO2, PM2.5, PM10) and multipollutant (NO2 and PM2.5, NO2 and PM10) models, where they adjustment for temperature and relative humidity.RESULTS: The overall 5-year average asthma admissions rate was 78 per 100 000 population during the study period. The annual average rate decreased to 46 per 100 000 population during 2020 (incidence rate ratio 0.58, 95% CI 0.42 to 0.81, p<0.001) compared to the prepandemic years (2015-2019). In single-pollutant analysis, we observed a significantly increased risk of asthma admission associated with each 1 μg/m3 increase in monthly concentrations of NO2 4% (95% CI 1.009% to 1.072%), PM2.5 3% (95% CI 1.006% to 1.052%) and PM10 1.8% (95% CI 0.999% to 1.038%). However, in the multipollutant regression model, the effect of each individual pollutant was attenuated.CONCLUSIONS: Ambient NO2 and PM2.5 air pollution exposure increased the risk of asthma admissions in this urban setting. Improvements in air quality during COVID-19 lockdown periods may have contributed to a substantially reduced acute asthma disease burden. Large-scale measures to improve air quality have potential to protect vulnerable people living with chronic asthma in urban areas.</p
Impacts of ambient air quality on acute asthma hospital admissions during the COVID-19 pandemic in Oxford City, UK: a time-series study
Objectives: The study aims to investigate the short-term associations between exposure to ambient air pollution (nitrogen dioxide (NO2), particulate matter pollution—particles with diameter<2.5 µm (PM2.5) and PM10) and incidence of asthma hospital admissions among adults, in Oxford, UK.
Design:Â Retrospective time-series study.
Setting: Oxford City (postcode areas OX1–OX4), UK.
Participants: Adult population living within the postcode areas OX1–OX4 in Oxford, UK from 1 January 2015 to 31 December 2021.
Primary and secondary outcome measures:Â Hourly NO2, PM2.5Â and PM10Â concentrations and meteorological data for the period 1 January 2015 to 31 December 2020 were analysed and used as exposures. We used Poisson linear regression analysis to identify independent associations between air pollutant concentrations and asthma admissions rate among the adult study population, using both single (NO2, PM2.5, PM10) and multipollutant (NO2Â and PM2.5, NO2Â and PM10) models, where they adjustment for temperature and relative humidity.
Results: The overall 5-year average asthma admissions rate was 78 per 100 000 population during the study period. The annual average rate decreased to 46 per 100 000 population during 2020 (incidence rate ratio 0.58, 95% CI 0.42 to 0.81, p<0.001) compared to the prepandemic years (2015–2019). In single-pollutant analysis, we observed a significantly increased risk of asthma admission associated with each 1 μg/m3 increase in monthly concentrations of NO2 4% (95% CI 1.009% to 1.072%), PM2.5 3% (95% CI 1.006% to 1.052%) and PM10 1.8% (95% CI 0.999% to 1.038%). However, in the multipollutant regression model, the effect of each individual pollutant was attenuated.
Conclusions:Â Ambient NO2Â and PM2.5Â air pollution exposure increased the risk of asthma admissions in this urban setting. Improvements in air quality during COVID-19 lockdown periods may have contributed to a substantially reduced acute asthma disease burden. Large-scale measures to improve air quality have potential to protect vulnerable people living with chronic asthma in urban areas
- …