467 research outputs found

    Nitric Oxide: Implications for Vascular and Endovascular Surgery

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    AbstractNitric oxide has a key role in vascular homeostasis. It plays a protective role by suppressing abnormal proliferation of vascular smooth muscle following various pathological situations including atherosclerosis and restenosis after vascular interventions such as balloon angioplasty, stent deployment and bypass grafting. It also has strong antiplatelet and anti-thrombogenic properties. In this review, possible applications to daily vascular and endovascular surgery practice, including systemic use of NO donors, enhancing endogenous production of NO by L-arginine and gene therapy, local delivery strategies and coating stents and grafts with NO-delivering/enhancing chemicals are reviewed

    Leishmaniose cutanée dans le foyer urbain de Sanliurfa (Turquie)

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    In the leishmaniasis focus of Sanliurfa, south-east Turquey, phlebotomine sandflies catches in houses and stables seem to confirm the parasitological data with an urban cycle due to #Leishmania tropica transmitted by #Phlebotomus sergenti. The incidence could be reduce drastically by intradomiciliar and stables insecticide pulverisations. (Résumé d'auteur

    Controllable Synthesis of Gold Nanoparticles in Aqueous Solution by Microwave Assisted Flow Chemistry

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    The development of energy efficient, reproducible, and high throughput approaches to gold nanoparticle (Au-NP) synthesis has gained increasing attention over the past decades due to applications in biomedicine, sensors, and catalysis. In this work, single mode microwave irradiation is for the first time combined with microflow chemistry to fabricate Au-NPs continuously and reproducibly with controllable size in an aqueous solution. The major experimental parameters including microwave power, citrate-to-gold molar ratio ([Cit]/[Au]), and reaction residence time have been investigated systematically. As indicated by TEM, the mean particle width of the synthesized Au-NPs is between 4 and 15 nm with mean aspect ratio between ∼1.4 and 2.2 after only 90 s of microwave irradiation. Furthermore, the Au particle morphology can be manipulated from nanowires to nanoparticles by adjusting the [Cit]/[Au] ratio. HRTEM analysis of the produced Au-NPs and UV–vis spectroscopy suggests a correlation between the red-shifted surface plasmon resonance peak and the particle aspect ratio that is probably dependent on the creation of particle–particle junctions, which alter both the size and the aspect ratio of the Au-NPs. The synthesis further demonstrated high reproducibility

    Wearable Nano-Based Gas Sensors for Environmental Monitoring and Encountered Challenges in Optimization

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    With a rising emphasis on public safety and quality of life, there is an urgent need to ensure optimal air quality, both indoors and outdoors. Detecting toxic gaseous compounds plays a pivotal role in shaping our sustainable future. This review aims to elucidate the advancements in smart wearable (nano)sensors for monitoring harmful gaseous pollutants, such as ammonia (NH3), nitric oxide (NO), nitrous oxide (N2O), nitrogen dioxide (NO2), carbon monoxide (CO), carbon dioxide (CO2), hydrogen sulfide (H2S), sulfur dioxide (SO2), ozone (O3), hydrocarbons (CxHy), and hydrogen fluoride (HF). Differentiating this review from its predecessors, we shed light on the challenges faced in enhancing sensor performance and offer a deep dive into the evolution of sensing materials, wearable substrates, electrodes, and types of sensors. Noteworthy materials for robust detection systems encompass 2D nanostructures, carbon nanomaterials, conducting polymers, nanohybrids, and metal oxide semiconductors. A dedicated section dissects the significance of circuit integration, miniaturization, real-time sensing, repeatability, reusability, power efficiency, gas-sensitive material deposition, selectivity, sensitivity, stability, and response/recovery time, pinpointing gaps in the current knowledge and offering avenues for further research. To conclude, we provide insights and suggestions for the prospective trajectory of smart wearable nanosensors in addressing the extant challenges

    A Case study of light pollution in France after the change in legislation

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    France issued a decree to restrict and prohibit mainly outdoor lighting effective from January 1st, 2019. Effectiveness of this legislation has been evaluated in this study using GIS data which was first used in \cite{2020MNRAS.493.1204A} (so called astroGIS database - \url{astrogis.org}). A subset of Artificial Light layer of astroGIS database has been adapted for years between January 2012 and December 2019. During 2019, radiance of 1.9×1091.9 \times 10^{9} W cm−2^{-2} sr−1^{-1} has been released into space. Annual light pollution in France decreased by 6\% after the enactment of artificial light legislation. France continue to have potential Dark Sky Park locations for example cities like Indre, Lot, Nievre and Creuse having the lowest light pollution values. A strong correlation between population and light pollution (R≃0.83R\simeq 0.83) has been observed. A similar but a weak correlation can also be observed for GDP (R≃0.28R\simeq 0.28). However, it is still too early to justify whether the improvements observed in the dataset are due to the enactment of the legislation or not.Comment: 10 pages, 4 figures, 2 tables, Submitted to Astrophysics and Space Scienc

    The temporal analysis of light pollution in Turkey using VIIRS data

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    © 2021, The Author(s), under exclusive licence to Springer Nature B.V.Artificial Light pollution (AL) in Turkey and in Turkish observatories between 2012–2020 have been studied using the archival data of Visible Infrared Imaging Radiometer Suite (VIIRS) instrument. The astroGIS database has been used in processing the data (astrogis.org) Aksaker et al. (2020a). The total energy released to space from Turkey increased by 80% in 2019 with respect to 2012. In the span of the dataset, a steady and continuous increase has been observed throughout all cities of the country. On the other hand, Dark Sky Park locations, East and Southeast Anatolian regions and mostly rural areas around the cities kept their AL level constant. Four demographic parameters have been studied and they were found to be correlated very well with AL: Population (R≃ 0.90); GDP (R≃ 0.87); Total Power Consumption (R≃ 0.66) and Outdoor Lightening (R≃ 0.67). Contrary to countries acting to prevent AL increases, Turkey seems to be at the beginning of an era where AL will arithmetically increase throughout the country and enormous amount of energy will continuously escape to space and therefore will be wasted. Therefore, a preventive legislation, especially for invaluable astronomical site locations such as TURAG, TUG, DAG and ÇAAM where each is counted as a truly dark site due to their SQM values, has to be enacted in Turkey, in very near future

    Microwave Intensified Synthesis: Batch and Flow Chemistry

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    Many studies have been conducted on organic and inorganic synthesis by microwave heating owing to its special heating mechanism, leading to improved reaction rate, higher purity and yields. We specifically demonstrated microwave heating in the fabrication of nanoparticles and polyester. By fine-tuning the microwave and experimental parameters, the materials prepared have shown excellent physical and bio-properties, e. g. narrow particle size distribution, controlled morphology, varied molecular structure and so forth. We further highlight the recent procedure of using fluidic reactors on preparing both metals and metal oxides nanoparticles. The experimental design strategies and fundamentals of the microwave interaction with chemicals are presented. Furthermore, the key factors and issues facing in this area are also discussed

    Global Site Selection for Astronomy

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    A global site selection for astronomy was performed with 1 km spatial resolution (∼\sim 1 Giga pixel in size) using long term and up-to-date datasets to classify the entire terrestrial surface on the Earth. Satellite instruments are used to get the following datasets of Geographical Information System (GIS) layers: Cloud Coverage, Digital Elevation Model, Artificial Light, Precipitable Water Vapor, Aerosol Optical Depth, Wind Speed and Land Use -- Land Cover. A Multi Criteria Decision Analysis (MCDA) technique is applied to these datasets creating four different series where each layer will have a specific weight. We introduce for the first time a ``Suitability Index for Astronomical Sites'' namely, SIAS. This index can be used to find suitable locations and to compare different sites or observatories. Mid-western Andes in South America and Tibetan Plateau in west China were found to be the best in all SIAS Series. Considering all the series, less than 3 \% of all terrestrial surfaces are found to be the best regions to establish an astronomical observatory. In addition to this, only approximately 10 \% of all current observatories are located in good locations in all SIAS series. Amateurs, institutions or countries aiming to construct an observatory could create a short-list of potential site locations using layout of SIAS values for each country without spending time and budget.The outcomes and datasets of this study has been made available through a web site, namely ``Astro GIS Database'' on \texttt{\url{www.astrogis.org}}.Comment: 19 Pages, 4 Figures, 7 tables, Accepted for publication in MNRA
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