1,067 research outputs found
SAMplus: adaptive optics at optical wavelengths for SOAR
Adaptive Optics (AO) is an innovative technique that substantially improves
the optical performance of ground-based telescopes. The SOAR Adaptive Module
(SAM) is a laser-assisted AO instrument, designed to compensate ground-layer
atmospheric turbulence in near-IR and visible wavelengths over a large Field of
View. Here we detail our proposal to upgrade SAM, dubbed SAMplus, that is
focused on enhancing its performance in visible wavelengths and increasing the
instrument reliability. As an illustration, for a seeing of 0.62 arcsec at 500
nm and a typical turbulence profile, current SAM improves the PSF FWHM to 0.40
arcsec, and with the upgrade we expect to deliver images with a FWHM of
arcsec -- up to 0.23 arcsec FWHM PSF under good seeing
conditions. Such capabilities will be fully integrated with the latest SAM
instruments, putting SOAR in an unique position as observatory facility.Comment: To appear in Proc. SPIE 10703 (Ground-based and Airborne
Instrumentation for Astronomy VII; SPIEastro18
Entwicklung und Charakterisierung eines kolloidalen Lithographieverfahrens zur Herstellung plasmonischer Biosensoren
Periodische Lochgitter in Metallfilmen zeigen ĂŒberraschende optische Eigenschaften, welche auf die resonante Anregung von OberflĂ€chenplasmonen (OP) zurĂŒckzufĂŒhren sind. So kann eine verstĂ€rkte Transmission bei ResonanzwellenlĂ€ngen der OP beobachtet werden, welche unter anderem vom Brechungsindex der Umgebung des Metallfilms abhĂ€ngt. In einer Reihe von Anwendungsfeldern wird der Einsatz von Lochgittern gegenwĂ€rtig untersucht, darunter die Verwendung in chemischen oder biologischen Sensoren. Trotz des Anwendungspotentials dieser Strukturen erfordert die Herstellung mit gegenwĂ€rtigen Methoden den Einsatz kostspieliger Verfahren oder ist nur mit geringem Durchsatz möglich. In dieser Arbeit wurde daher ein neuartiges, lithographisches Verfahren entwickelt, mit dem sich Lochgitter in Metallfilmen mit rein chemischen Methoden herstellen lassen. Hierzu wurde zunĂ€chst ein simples Verfahren entwickelt, um zweidimensionale Kolloidkristalle herzustellen. Dabei wurden Hydrogel-MikrosphĂ€ren aus Poly-(N-isopropylacrylamid) (PolyNIPAM) eingesetzt, da diese eine Reihe bemerkenswerte Eigenschaften aufweisen. Insbesondere fĂŒhrt der reversible VolumenphasenĂŒbergang der MikrosphĂ€ren zur Bildung nicht-dichtest-gepackter Kristalle, welche direkt als lithographische Maske in den nachfolgenden Prozessschritten eingesetzt werden können. Daneben kann die induzierte OberflĂ€chenaktivitĂ€t ausgenutzt werden, um durch mechanisches Tempern die Anzahl der Kristallgrenzen drastisch zu reduzieren. Dabei konnten Einkristalle erhalten werden, dessen Ausdehnung in der GröĂenordnung von mm^2 liegt. Der kolloidale Kristall fungiert im folgenden Prozessschritt als lithographische Maske bei der Erzeugung eines Lochgitters in einem Goldfilm. Dieser Schritt basiert auf der gerichteten Bindung von Goldnanopartikeln an das Glassubstrat und deren VergröĂerung durch chemische Goldabscheidung. Hierbei wurde unter anderem untersucht, wie sich die strukturellen Eigenschaften, wie Gitterkonstante, OberflĂ€chenrauheit und Filmdicke, prĂ€zise einstellen lassen. So kann etwa durch den Einsatz von MikrosphĂ€ren variablen Durchmessers die Gitterkonstanten zwischen ~ 300 - 1200 nm eingestellt werden. Dies ermöglicht die prĂ€zise Kontrolle der Position der Transmissions-Maxima im Spektrum. Die Transmission der erzeugten Lochgitter wurde im dritten Teil der Arbeit eingehend untersucht und wird erwartungsgemÀà vor allem durch die Gitterkonstante bestimmt. Insbesondere wurde der Einfluss der Struktur, wie etwa die Ordnung des Lochgitters, auf die optischen Eigenschaften untersucht. Daneben wurde die SensitivitĂ€t der Resonanzen auf Ănderungen des Brechungsindex bestimmt. Je nach betrachteter spektraler Signatur und Gitterkonstante ergab sich dabei die SensitivitĂ€t zu 300 - 800 nm/RIU. Sie ist damit vergleichbar mit Lochgittern, welche mit aufwendigeren Verfahren hergestellt wurden. Das letzte Kapitel beschĂ€ftigt sich mit der Entwicklung eines Modellsystems, das kĂŒnftig bei der Untersuchung des invasiven Potentials von Tumorzellen eingesetzt werden könnte. Das System basiert auf einem Lochgitter, welches mit einem Gelatinefilm definierter Dicke beschichtet wird. Durch die AktivitĂ€t von Kollagenasen, welche typischerweise von invasiven Tumorzellen sezerniert werden, kann die Gelatine abgebaut werden. In ersten Experimenten konnte gezeigt werden, dass der enzymatische Abbau im Transmissionsspektrum der Lochgitter verfolgt werden kann. Dies belegt die praktische Relevanz der untersuchten Lochgitter
The operational experience of private owners of small-sized care homes in China: a qualitative study
Background: Private small-sized care homes (<50 beds) have proliferated across China, however, until recently little was known about the characteristics of such institutions, and the challenges and the problems faced by their owners. This study aimed to explore the characteristics of small-sized, privately-owned care homes in the Peopleâs Republic of China; and to understand the motivation and challenges faced by their owners. Methods: This study used an interpretative phenomenological analysis approach of qualitative research. Owners of eight small-sized private care homes located in two cities of Henan Province, China, were interviewed using semi-structured interviews. Results: Four themes and eight subthemes were identified: 1. Motivation for establishing a care home business; 2. Certification and establishing a legal footing for the business; 3. Operational challenges; 4. Future business development. The study found that the development of privately owned small-sized care homes faced great challenges and critical survival problems due to policies, staffing, and management issues. There is a lack of regulations about the safety and quality of care provided for older people and a lack of legal protections for the owners of small-sized private care homes. Conclusion: The study suggests that formal regulations and provisions are needed to support these smaller-sized private care homes. Monitoring is also needed to ensure the quality of care. It also suggests that there needs more support by policymakers as well as provision monitoring services to improve quality of care in these care homes. Care regulations and standards are not unique to China so findings from this study can be applied to places where there are similar situations or if there are aged care services still developing
Greek OreganoâA Niche Crop for Iowa?
The project was the result of a discussion with an Iowa-based company specializing in allnatural health care products for livestock and companion animals. They are interested in finding local sources of oregano oil because they currently import more than 8,000 lb annually from a European supplier. Greek oregano oil is used in animal care products and other pharmaceuticalsfor its carvacrol content, which has shown to have antimicrobial properties. Their product specifications require oil that contains a minimum of 65% carvacrol and 3% thymol
Granulocytic sarcoma (chloroma) causing spinal cord compression
Granulocytic sarcoma (chloroma) is a rare solid tumor of myelogenous stem cells, usually appearing in patients with acute myelogenous leukemia and less commonly in patients with chronic myelogenous leukemia or myeloproliferative disorders. We present a spinal epidural granulocytic sarcoma causing thoracic spinal cord compression in a patient with chronic anemia secondary to myelofibrosis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46661/1/234_2004_Article_BF00588708.pd
Cardiovascular outcomes following a respiratory tract infection among adults with non-CF bronchiectasis: a general population based study
Rationale: Studies suggest that people with bronchiectasis are at increased risk of cardiovascular co-morbidities.
Objectives: We aimed to quantify the relative risk of incident cardiovascular events following a respiratory tract infection amongst people with bronchiectasis.
Methods: Using UK electronic primary care records, we conducted a within-person comparison using the self-controlled case series method. We calculated the relative risk of first time cardiovascular events (either first myocardial infarction [MI] or stroke) following a respiratory tract infection compared with the individualâs baseline risk.
Results: Our cohort consisted of 895 individuals with non-CF bronchiectasis with a first MI or stroke and at least one respiratory tract infection. There was an increased rate of first time cardiovascular events in the 91 day period after a respiratory tract infection (Incidence Rate Ratio [IRR] 1.56; 95% CI 1.20 to 2.02). The rate of a first cardiovascular event was highest in the first three days following a respiratory tract infection (IRR 2.73, 95% CI 1.41 to 5.27).
Conclusions: These data suggest that respiratory tract infections are strongly associated with a transient increased risk of first time MI or stroke amongst people with bronchiectasis. As respiratory tract infections are six times more common in people with bronchiectasis than the general population, the increased risk has a disproportionately greater impact in these individuals. These findings may have implications for including cardiovascular risk modifications in airway infection treatment pathways in this population
Stimulated Muscle Contractions Regulate Membrane-Bound and Soluble TLR4 to Prevent LPS-Induced Signaling and Myotube Atrophy in Skeletal Muscle Cells
Toll-like receptor 4 (TLR4) activation by lipopolysaccharides (LPS) contributes to chronic inflammation and causes upregulation of muscle atrophy signaling pathways. Exercise can suppress LPS/TLR4 axis activation by reducing the expression of TLR4 on immune cells. It is unknown how this regulation occurs, and it is not clear how exercise affects TLR4 on skeletal muscle. PURPOSE: To uncover the nature and mechanisms by which exercise affects TLR4 expression and intracellular signaling using cell culture models and human experiments. METHODS: C2C12 myotubes were subjected to electrical pulse stimulation (EPS) with and without subsequent treatment with 500 ng/mL lipopolysaccharide (LPS) along with corresponding control conditions. To investigate the effect of muscle contraction on the regulation of TLR4 in-vivo, we analyzed PBMC and serum samples from eight recreationally active men that completed 60-minutes of cycling at a moderate intensity (65% of VO2max). RESULTS: In-vitro, LPS decreased membrane-bound TLR4, increased TLR4 signaling (decreased inhibitor of ÎșBα), and induced myotube atrophy. However, stimulated muscle contractions decreased membrane-bound TLR4, increased soluble TLR4 (sTLR4), and prevented LPS-induced signaling and myotube atrophy. In human participants, a single bout of moderate-intensity exercise decreased membrane-bound TLR4 on PBMCs and increased serum-borne sTLR4. CONCLUSION: These experiments support exercise may exert a novel anti-catabolic/ anti-inflammatory effect by increasing sTLR4 and decreasing TLR4 expressed on the muscle membrane. These results could help improve interventions for conditions associated with TLR4-mediated inflammation and muscle atrophy, such as diabetes, sarcopenia, and cancer cachexia
A compilation, tabulation and analysis of spelling errors made by pupils in grades four, five, and six in free writing of sentences using given stimuli words
Thesis (M.A.)--Boston Universit
Personal exposure to air pollution and respiratory health of COPD patients in London
Previous studies have investigated the effects of air pollution on chronic obstructive pulmonary disease (COPD) patients using either fixed site measurements or a limited number of personal measurements, usually for one pollutant and a short time period. These limitations may introduce bias and distort the epidemiological associations as they do not account for all the potential sources or the temporal variability of pollution.We used detailed information on individuals' exposure to various pollutants measured at fine spatio-temporal scale to obtain more reliable effect estimates. A panel of 115 patients was followed up for an average continuous period of 128â
days carrying a personal monitor specifically designed for this project that measured temperature, PM10, PM2.5, NO2, NO, CO and O3 at one-minute time resolution. Each patient recorded daily information on respiratory symptoms and measured peak expiratory flow (PEF). A pulmonologist combined related data to define a binary variable denoting an "exacerbation". The exposure-response associations were assessed with mixed-effects models.We found that gaseous pollutants were associated with a deterioration in patients' health. We observed an increase of 16.4% (95% confidence interval: 8.6-24.6%), 9.4% (5.4-13.6%) and 7.6% (3.0-12.4%) in the odds of exacerbation for an interquartile range increase in NO2, NO and CO respectively. Similar results were obtained for cough and sputum. O3 was found to have adverse associations with PEF and breathlessness. No association was observed between particles and any outcome.Our findings suggest that, when considering total personal exposure to air pollutants, mainly the gaseous pollutants affect COPD patients' health
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