367 research outputs found
Can Image Enhancement Allow Radiation Dose to Be Reduced Whilst Maintaining the Perceived Diagnostic Image Quality Required for Coronary Angiography?
Objectives: The aim of this research was to quantify the reduction in radiation dose facilitated by image processing alone for percutaneous coronary intervention (PCI) patient angiograms, without reducing the perceived image quality required to confidently make a diagnosis. Methods: Incremental amounts of image noise were added to five PCI angiograms, simulating the angiogram as having been acquired at corresponding lower dose levels (10-89% dose reduction). Sixteen observers with relevant experience scored the image quality of these angiograms in three states - with no image processing and with two different modern image processing algorithms applied. These algorithms are used on state-of-the-art and previous generation cardiac interventional X-ray systems. Ordinal regression allowing for random effects and the delta method were used to quantify the dose reduction possible by the processing algorithms, for equivalent image quality scores. Results: Observers rated the quality of the images processed with the state-of-the-art and previous generation image processing with a 24.9% and 15.6% dose reduction respectively as equivalent in quality to the unenhanced images. The dose reduction facilitated by the state-of-the-art image processing relative to previous generation processing was 10.3%. Conclusions: Results demonstrate that statistically significant dose reduction can be facilitated with no loss in perceived image quality using modern image enhancement; the most recent processing algorithm was more effective in preserving image quality at lower doses. Advances in knowledge: Image enhancement was shown to maintain perceived image quality in coronary angiography at a reduced level of radiation dose using computer software to produce synthetic images from real angiograms simulating a reduction in dose
The time-dependent expression of keratins 5 and 13 during the reepithelialization of human skin wounds
The time-dependent reepithelialization of 55 human surgical skin wounds with a wound age between 8h and more than 2 months was investigated by the immunohistochemical localization of cytokeratins 5 and 13. A complete, rebuilt epidermal layer over the wound area was first detectable in a 5-day-old wound, while all wounds of more than 18 days duration contained a completely reepithelialized wound area. Between 5 and 18 days the basal layer of keratinocytes showed — in contrast to normal skin — only some cells positive for cytokeratin 5. In some, but not all lesions with a wound age of 13 days or more, a basal cell layer completely staining for cytokeratin 5 was demonstrable. This staining pattern was found in all skin wounds with a wound age of more than 23 days. The immunohistochemical detection of cytokeratin 13 which can be observed regularly in non-cornifying squamous epithelia provides no information for the time-estimation of human skin wounds, since no significant temporary expression of this polypeptide seems to occur during the healing of human skin wounds
The time-dependent rearrangement of the epithelial basement membrane in human skin wounds
In 62 human skin wounds (surgical wounds, stab wounds and lacerations after surgical treatment) we analyzed the immunohistochemical localization of collagen IV in the epithelial basement membrane. In 27 of these wounds the distribution of collagen VII, which represents a specific component of the basement membrane of stratified epithelia, was also analyzed. We were able to demonstrate a virtually identical co-distribution of both collagen IV and VII in the wound area with no significant time-dependent differences in the appearance of both collagen types. Fragments of the epithelial basement membrane could be detected in the wound area from as early as 4 days after wounding and after 8 days a complete restitution of the epithelial basement membrane was observed. In all cases with a wound age of more than 21 days the basement membrane was completely reformed over the former lesional area. The period between 8 and 21 days after wounding was characterized by a wide variability ranging from complete restitution to deposition of basement membrane fragments or total lack of the epidermal basement membrane
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African biomass burning is a substantial source of phosphorus deposition to the Amazon, Tropical Atlantic Ocean, and Southern Ocean
The deposition of phosphorus (P) from African dust is believed to play an important role in bolstering primary productivity in the Amazon Basin and Tropical Atlantic Ocean (TAO), leading to sequestration of carbon dioxide. However, there are few measurements of African dust in South America that can robustly test this hypothesis and even fewer measurements of soluble P, which is readily available for stimulating primary production in the ocean. To test this hypothesis, we measured total and soluble P in long-range transported aerosols collected in Cayenne, French Guiana, a TAO coastal site located at the northeastern edge of the Amazon. Our measurements confirm that in boreal spring when African dust transport is greatest, dust supplies the majority of P, of which 5% is soluble. In boreal fall, when dust transport is at an annual minimum, we measured unexpectedly high concentrations of soluble P, which we show is associated with the transport of biomass burning (BB) from southern Africa. Integrating our results into a chemical transport model, we show that African BB supplies up to half of the P deposited annually to the Amazon from transported African aerosol. This observational study links P-rich BB aerosols from Africa to enhanced P deposition in the Amazon. Contrary to current thought, we also show that African BB is a more important source of soluble P than dust to the TAO and oceans in the Southern Hemisphere and may be more important for marine productivity, particularly in boreal summer and fall
Design and methods of the Longitudinal Eating Disorders Assessment Project research consortium for veterans
Introduction
Military service members must maintain a certain body mass index and body fat percentage. Due to weight-loss pressures, some service members may resort to unhealthy behaviors that place them at risk for the development of an eating disorder (ED).
Objectives
To understand the scope and impact of EDs in military service members and veterans, we formed the Longitudinal Eating Disorders Assessment Project (LEAP) Consortium. LEAP aims to develop novel screening, assessment, classification, and treatment tools for veterans and military members with a focus on EDs and internalizing psychopathology.
Methods
We recruited two independent nationally representative samples of post-9/11 veterans who were separated from service within the past year. Study 1 was a four-wave longitudinal survey and Study 2 was a mixed-methods study that included surveys, structured-clinical interviews, and qualitative interviews.
Results
Recruitment samples were representative of the full population of recently separated veterans. Sample weights were created to adjust for sources of non-response bias to the baseline survey. Attrition was low relative to past studies of this population, with only (younger) age predicting attrition at 1-week follow-up.
Conclusions
We expect that the LEAP Consortium data will contribute to improved information about EDs in veterans, a serious and understudied problem
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Effect of end-wall riblets on radial turbine performance
This paper presents a detailed study of the impact of manufacturing residual riblets at the rotor hub surface of a radial inflow turbine on the flow within the rotor passages and their contribution to drag reduction. Numerical analysis has been used to study the effects of those features at design point conditions. Riblets with different height and spacing have been examined to determine the riblet geometry where the maximum drag reduction is achieved. The relative height of the riblets to rotor inlet blade height was introduced to generalise the results. At the end of this study the results were compared with the available data in literature. It was found that the introduction of riblets could reduce the wall shear stress at the hub surface, while they contribute to increasing the streamwise vorticity within the rotor passage. For the geometries tested, the minimum drag was achieved using riblets with relative height hrel = 2.5% equivalent to 19.3 wall units. The results revealed that the spacing between riblets have a minor effect on their performance, this is due to the size of the streamwise vortex above the hub surface which will be discussed in this work
The Grizzly, November 15, 1985
Alcohol Policy Revisited: Campus Pub? • Landis Becomes UC\u27s First Full-Time Minister • Wellness Sponsors Adopt-A-Smoker Contest • Letters: Kane Downs Kegs; Security Remains Controversial • Reverant Reflections • In Search of Success: Linda Troutman Lands Job at Prudential • Berry Receives Fulbright Scholarship • Protheatre • Bears Take ECAC for Third Time • McCloskey Breaks TD Pass Record Another One • Cross Country: To Sum it Up • Women\u27s Field Hockey Falters in First Round • Amazons Too Tough • Lindbergh Tragedy: We Love You Pelle! • College Degree Becoming More Valuablehttps://digitalcommons.ursinus.edu/grizzlynews/1152/thumbnail.jp
Languages cool as they expand: Allometric scaling and the decreasing need for new words
We analyze the occurrence frequencies of over 15 million words recorded in millions of books published during the past two centuries in seven different languages. For all languages and chronological subsets of the data we confirm that two scaling regimes characterize the word frequency distributions, with only the more common words obeying the classic Zipf law. Using corpora of unprecedented size, we test the allometric scaling relation between the corpus size and the vocabulary size of growing languages to demonstrate a decreasing marginal need for new words, a feature that is likely related to the underlying correlations between words. We calculate the annual growth fluctuations of word use which has a decreasing trend as the corpus size increases, indicating a slowdown in linguistic evolution following language expansion. This ‘‘cooling pattern’’ forms the basis of a third statistical regularity, which unlike the Zipf and the Heaps law, is dynamical in nature
Establishing a Large-Scale Field Experiment to Assess the Effects of Artificial Light at Night on Species and Food Webs
Artificial light at night (ALAN) is one of the most obvious hallmarks of human
presence in an ecosystem. The rapidly increasing use of artificial light has
fundamentally transformed nightscapes throughout most of the globe, although
little is known about how ALAN impacts the biodiversity and food webs of
illuminated ecosystems. We developed a large-scale experimental infrastructure
to study the effects of ALAN on a light-naïve, natural riparian (i.e.,
terrestrial-aquatic) ecosystem. Twelve street lights (20 m apart) arranged in
three rows parallel to an agricultural drainage ditch were installed on each
of two sites located in a grassland ecosystem in northern Germany. A range of
biotic, abiotic, and photometric data are collected regularly to study the
short- and long-term effects of ALAN on behavior, species interactions,
physiology, and species composition of communities. Here we describe the
infrastructure setup and data collection methods, and characterize the study
area including photometric measurements. None of the measured parameters
differed significantly between sites in the period before illumination.
Results of one short-term experiment, carried out with one site illuminated
and the other acting as a control, demonstrate the attraction of ALAN by the
immense and immediate increase of insect catches at the lit street lights. The
experimental setup provides a unique platform for carrying out
interdisciplinary research on sustainable lighting
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