430 research outputs found

    Implications of SARS-COV-2 infection in the diagnosis and management of the pediatric gastrointestinal disease

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    Gastrointestinal diseases such as celiac disease, functional gastrointestinal disorders (FGIDs), inflammatory bowel disease (IBDs) and acute or chronic diarrhea are quite frequent in the pediatric population. The approach, the diagnosis and management can be changed in the 2019 coronavirus disease (COVID-19) pandemic era. This review has focused on: i) the current understanding of digestive involvement in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected children and adolescents and the clinical implications of COVID-19 for pediatric gastroenterologists, ii) the impact of COVID-19 on the clinical approach to patients with pre-existing or onset diseases, including diagnosis and treatment, and iii) the role and limited access to the instrumental diagnosis such as digestive endoscopy. To date, it is unclear if immunosuppression in patients with IBD and chronic liver disease represents a risk factor for adverse outcomes. Scheduled outpatient follow-up visits may be postponed, especially in patients in remission. Conversely, telemedicine services are strongly recommended. The introduction of new therapeutic regimens should be made on an individual basis, discussing the benefits and risks with each patient. Furthermore, psychological care in all children with chronic disease and their parents should be ensured. All non-urgent and elective endoscopic procedures may be postponed as they must be considered at high risk of viral transmission. Finally, until SARS-CoV-2 vaccination is not available, strict adherence to standard social distancing protocols and the use of personal protective equipment should continue to be recommended

    Tailoring the electronic properties of silicon with cysteine: A first principle study

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    We discuss the electronic structure modifications induced on the dihydride-terminated Si(001) surface upon cysteine adsorption by means of ab initio calculations: several stable functionalization schemes are presented, providing different routes for biological recognition, surface nanostructuring, and biomolecular electronics applications. The resulting hybrid systems are discussed and compared in terms of stability, structural, and electronic properties. Based on our results, we propose STM and photoemission experiments to determine unambiguously the adsorption mechanism involved and the attached functional group

    Mode discrimination criterion for effective differential amplification in Yb-doped fiber design for high power operation

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    The mode discrimination criterion for single mode operation, usually considered in fiber amplifiers designed for high power operation, has been investigated and tested on three di erent fiber designs, a large pitch fiber and two symmetry free photonic crystal fibers. To have a significant collection of results, parameters like pump configuration, pump power, and amplifier length have been varied. The analysis has been carried out through the use of a custom numerical tool provided with e cient thermal and spatial amplification models. From the obtained results, it is possible to observe that the mode discrimination criterion is helpful but not strictly necessary to pledge an e ective single mode operation through di erential amplification. This fact extends the possibility for the study, as well as for the optimization, of di erent fiber designs. The use of advanced numerical analysis, which takes into consideration amplification along with thermally influenced modes guidance, becomes extremely useful for an e ective fiber design

    Transport methods and interactions for space radiations

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    A review of the program in space radiation protection at the Langley Research Center is given. The relevant Boltzmann equations are given with a discussion of approximation procedures for space applications. The interaction coefficients are related to solution of the many-body Schroedinger equation with nuclear and electromagnetic forces. Various solution techniques are discussed to obtain relevant interaction cross sections with extensive comparison with experiments. Solution techniques for the Boltzmann equations are discussed in detail. Transport computer code validation is discussed through analytical benchmarking, comparison with other codes, comparison with laboratory experiments and measurements in space. Applications to lunar and Mars missions are discussed

    First proof-of-principle of inorganic lead halide perovskites deposition by magnetron-sputtering

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    The present work reports the application of RF-magnetron sputtering technique to realize CsPbBr 3 70 nm thick films on glass substrate by means of a one-step procedure. The obtained films show highly uniform surface morphology and homogeneous thickness as evidenced by AFM and SEM investigations. XRD measurements demonstrate the presence of two phases: a dominant orthorhombic CsPbBr 3 and a subordinate CsPb 2 Br 5 . Finally, XPS data reveals surface bromine depletion respect to the stoichiometrical CsPbBr 3 composition, nevertheless photoluminescence spectroscopy results confirm the formation of a highly luminescent film. These preliminary results demonstrate that our approach could be of great relevance for easy fabrication of large area perovskite thin films. Future developments, based on this approach, may include the realization of multijunction solar cells and multicolor light emitting devices

    Threshold meson production and cosmic ray transport

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    An interesting accident of nature is that the peak of the cosmic ray spectrum, for both protons and heavier nuclei, occurs near the pion production threshold. The Boltzmann transport equation contains a term which is the cosmic ray flux multiplied by the cross section. Therefore when considering pion and kaon production from proton-proton reactions, small cross sections at low energy can be as important as larger cross sections at higher energy. This is also true for subthreshold kaon production in nuclear collisions, but not for subthreshold pion production.Comment: 9 pages, 1 figur

    Structured self-monitoring of blood glucose is associated with more appropriate therapeutic interventions than unstructured self-monitoring: A novel analysis of data from the PRISMA trial

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    Aims: To investigate the relationship between single therapeutic interventions and indicators of glycemic control in the PRISMA trial, a large study comparing the effects of intensive structured SMBG (ISM) vs. active control (AC) in non-insulin-treated type 2 diabetes (T2D). Methods: Information was collected at four time points, corresponding to months 3, 6, 9, and 12 and visits 2, 3, 4, and 5, respectively. Data on therapeutic interventions, HbA1c levels and the number of hypoglycemic episodes at each visit were analyzed. Results: Intensification of drug therapy occurred in 20.3% vs. 15.6%, and no change in 71.8% vs. 78.7% of visits for the ISM and AC groups, respectively. On the other hand, de-intensification and redistribution of drugs and/or drug dose occurred in a similar proportion of visits. Intensification of drug therapy in both groups was associated with significant reductions in HbA1c vs. the previous visit, while de-intensification of therapy led to a significant increase in HbA1c in the AC group only. Conclusions. Our data strongly support that structured SMBG has clinical value in reducing HbA1c in non-insulin-treated T2D and suggest that this clinical benefit may be mediated by more appropriate and timely changes in drug therapy

    Enhanced Photostability and Photoactivity of Ruthenium Polypyridyl-Based Photocatalysts by Covalently Anchoring Onto Reduced Graphene Oxide

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    \ua9 2024 The Authors. Published by American Chemical Society. Recent studies toward finding more efficient ruthenium metalloligands for photocatalysis applications have shown that the derivatives of the linear [Ru(dqp)2]2+ (dqp: 2,6-di(quinolin-8-yl)-pyridine) complexes hold significant promise due to their extended emission lifetime in the μs time scale while retaining comparable redox potential, extinction coefficients, and absorption profile in the visible region to [Ru(bpy)3]2+ (bpy: 2,2′-bipyridine) and [Ru(tpy)2]2+ (tpy: 2,2′:6′,2″-terpyridine) complexes. Nevertheless, its photostability in aqueous solution needs to be improved for its widespread use in photocatalysis. Carbon-based supports have arisen as potential solutions for improving photostability and photocatalytic activity, yet their effect greatly depends on the interaction of the metal complex with the support. Herein, we present a strategy for obtaining Ru-polypyridyl complexes covalently linked to aminated reduced graphene oxide (rGO) to generate novel materials with long-term photostability and increased photoactivity. Specifically, the hybrid Ru(dqp)@rGO system has shown excellent photostable behavior during 24 h of continual irradiation, with an enhancement of 10 and 15% of photocatalytic dye degradation in comparison with [Ru(dqp)2]2+ and Ru(tpy)@rGO, respectively, as well as remarkable recyclability. The presented strategy corroborates the potential of [Ru(dqp)2]2+ as an interesting photoactive molecule to produce more advantageous light-active materials by covalent attachment onto carbon-based supports

    Improved Spacecraft Materials for Radiation Shielding

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    In the execution of this proposal, we will first examine current and developing spacecraft materials and evaluate their ability to attenuate adverse biological mutational events in mammalian cell systems and reduce the rate of cancer induction in mice harderian glands as a measure of their protective qualities. The HZETRN code system will be used to generate a database on GCR attenuation in each material. If a third year of funding is granted, the most promising and mission-specific materials will be used to study the impact on mission cost for a typical Mars mission scenario as was planned in our original two year proposal at the original funding level. The most promising candidate materials will be further tested as to their transmission characteristics in Fe and Si ion beams to evaluate the accuracy of the HZETRN transmission factors. Materials deemed critical to mission success may also require testing as well as materials developed by industry for their radiation protective qualities (e.g., Physical Sciences Inc.) A study will be made of designing polymeric materials and composite materials with improved radiation shielding properties as well as the possible improvement of mission-specific materials
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