57 research outputs found
Metal-Enhanced Near-Infrared Fluorescence by Micropatterned Gold Nanocages
In metal-enhanced fluorescence (MEF), the localized surface plasmon
resonances of metallic nanostructures amplify the absorption of excitation
light and assist in radiating the consequent fluorescence of nearby molecules
to the far-field. This effect is at the base of various technologies that have
strong impact on fields such as optics, medical diagnostics and biotechnology.
Among possible emission bands, those in the near-infrared (NIR) are
particularly intriguing and widely used in proteomics and genomics due to its
noninvasive character for biomolecules, living cells, and tissues, which
greatly motivates the development of effective, and eventually multifunctional
NIR-MEF platforms. Here we demonstrate NIR-MEF substrates based on Au nanocages
micropatterned with a tight spatial control. The dependence of the fluorescence
enhancement on the distance between the nanocage and the radiating dipoles is
investigated experimentally and modeled by taking into account the local
electric field enhancement and the modified radiation and absorption rates of
the emitting molecules. At a distance around 80 nm, a maximum enhancement up to
2-7 times with respect to the emission from pristine dyes (in the region 660
nm-740 nm) is estimated for films and electrospun nanofibers. Due to their
chemical stability, finely tunable plasmon resonances, and large light
absorption cross sections, Au nanocages are ideal NIR-MEF agents. When these
properties are integrated with the hollow interior and controllable surface
porosity, it is feasible to develop a nanoscale system for targeted drug
delivery with the diagnostic information encoded in the fluorophore.Comment: 41 pages, 18 figure
Assessing Risks Awareness in Operating Rooms among Post-Graduate Students: A Pilot Study
Background: In this study, we promote a global approach to occupational risk perception in order to improve occupational health and safety training programs. The study investigates
the occupational risk perception of operating room healthcare workers using an Analytic Hierarchy
Process approach. Methods: A pilot study was carried out through a cross-sectional survey in a university hospital in Southern Italy. An ad hoc questionnaire was administered to enrolled medical
post-graduate students working in the operating room. Results: Fifty medical specialists from seven
fields (anaesthetists, digestive system surgeons, general surgeons, maxillofacial surgeons, thoracic
surgeons, urologists, and gynaecologists) were questioned about perceived occupational risk by
themselves. Biological, ionizing radiation, and chemical risks were the most commonly perceived in
order of priority (w = 0.300, 0.219, 0.210). Concerning the biological risk, gynaecologists unexpected
perceived this risk as less critical (w = 0.2820) than anaesthesiologists (w = 0.3354), which have the lowest perception of the risk of ionizing radiation (w = 0.1657). Conclusions: Prioritization methods
could improve risk perception in healthcare settings and help detect training needs and perform
sustainable training programs
Finite-time erasing of information stored in fermionic bits
We address the issue of minimizing the heat generated when erasing the information stored in an array of quantum dots in finite time. We identify the fundamental limitations and trade-offs involved in this process and analyze how a feedback operation can help improve it
Diagnosis, treatment and prevention of pediatric obesity: consensus position statement of the Italian Society for Pediatric Endocrinology and Diabetology and the Italian Society of Pediatrics
The Italian Consensus Position Statement on Diagnosis, Treatment and Prevention of Obesity in Children and Adolescents integrates and updates the previous guidelines to deliver an evidence based approach to the disease. The following areas were reviewed: (1) obesity definition and causes of secondary obesity; (2) physical and psychosocial comorbidities; (3) treatment and care settings; (4) prevention.The main novelties deriving from the Italian experience lie in the definition, screening of the cardiometabolic and hepatic risk factors and the endorsement of a staged approach to treatment. The evidence based efficacy of behavioral intervention versus pharmacological or surgical treatments is reported. Lastly, the prevention by promoting healthful diet, physical activity, sleep pattern, and environment is strongly recommended since the intrauterine phase
Global maps of soil temperature
Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world\u27s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (−0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications
Global maps of soil temperature
Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km² resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e., offset) between in-situ soil temperature measurements, based on time series from over 1200 1-km² pixels (summarized from 8500 unique temperature sensors) across all the world’s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in-situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications
Global maps of soil temperature.
Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications
The ductular reaction in chronic liver disease : friend or foe ?
Cirrhosis and hepatocellular carcinoma (HCC), end stages of all chronic liver diseases, are characterized by expansion of small immature cholangiocytes – a mechanism named ductular reaction (DR). DR cells are believed to be progenitors able to differentiate in cholangiocytes or in hepatocytes. We lack evidence of the fate and role of the DR during chronic liver disease. We demonstrated here that DR cells adapt their phenotype accordingly to the liver injury: in severe hepatocellular damage, DR cells expand as biliary epithelium and establish new duct-canaliculi junctions favoring the drainage of bile; in the chronic fibrotic liver, DR cells differentiate into hepatocytes refueling the liver parenchyma with young and strong hepatocytes. Also, DR cells do not give rise to HCC and DR-derived hepatocytes are less susceptible to carcinogenesis than native ones. Thus, DR cells can be considered an ally for liver regeneration and its in vivo stimulation may salvage liver failure.(BIFA - Sciences biomédicales et pharmaceutiques) -- UCL, 201
Improving the persistence of first-year undergraduate women in computer science
This paper describes a study of undergraduate women’s retention in the first-year of the computer science major at the University of Pennsylvania for the purpose of identifying the underlying issues responsible for attrition. The subsequent steps taken by the faculty to improve women’s retention is also discussed
Sundials in the shade: A study of women\u27s persistence in the first year of a computer science program in a selective university
Currently women are underrepresented in departments of computer science, making up approximately 18% of the undergraduate enrollment in selective universities. Most attrition in computer science occurs early in this major, in the freshman and sophomore years, and women drop out in disproportionately greater numbers than their male counterparts. Taking an ethnographic approach to investigating women\u27s experiences and progress in the first year courses in the computer science major at the University of Pennsylvania, this study examined the pre-college influences that led these women to the major and the nature of their experiences in and outside of class with faculty, peers, and academic support services. This study sought an understanding of the challenges these women faced in the first year of the major with the goal of informing institutional practice about how to best support their persistence. The research reviewed for this study included patterns of leaving majors in science, math and engineering (Seymour & Hewitt 1997), the high school preparation needed to pursue math and engineering majors in college (Strenta, Elliott, Adair, Matier, & Scott, 1994), and intervention programs that have positively impacted persistence of women in computer science (Margolis & Fisher, 2002). The research method of this study employed a series of personal interviews over the course of one calendar year with fourteen first year women who had either declared on intended to declare the computer science major in the School of Engineering and Applied Science at the University of Pennsylvania. Other data sources were focus groups and personal interviews with faculty, administrators, admissions and student life professionals, teaching assistants, female graduate students, and male first year students at the University of Pennsylvania. This study found that the women in this study group came to the University of Pennsylvania with a thorough grounding in mathematics, but many either had an inadequate background in computer science, or at least perceived inadequacies in their background, which prevented them from beginning the major on an equal footing with their mostly male peers and caused some to lose confidence and consequently interest in the major. Issues also emanated from their gender-minority status in the Computer and Information Science Department, causing them to be socially isolated from their peers and further weakening their resolve to persist. These findings suggest that female first year students could benefit from multiple pathways into the major designed for students with varying degrees of prior experience with computer science. In addition, a computer science community within the department characterized by more frequent interaction and collaboration with faculty and peers could positively impact women\u27s persistence in the major
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