4,016 research outputs found
Prediction of two-phase choked-flow through safety valves
Different models of two-phase choked flow through safety valves are applied in
order to evaluate their capabilities of prediction in different thermal-hydraulic conditions.
Experimental data available in the literature for two-phase fluid and subcooled liquid upstream
the safety valve have been compared with the models predictions. Both flashing flows and non-
flashing flows of liquid and incondensable gases have been considered.
The present paper
shows that for flashing flows good predictions are obtained by using the two-phase valve
discharge coefficient defined by Lenzing and multiplying it by the critical flow rate in an ideal
nozzle evaluated by either Omega Method or the Homogeneous Non-equilibrium Direct
Integration. In case of non-flashing flows of water and air, Leung/Darby formulation of the
two-phase valve discharge coefficient together with the Omega Method is more suitable to the
prediction of flow rate
Chlorophyll fluorescence data reveals climate-related photosynthesis seasonality in Amazonian forests
This is the final version of the article. Available from MDPI via the DOI in this record.Amazonia is theworld largest tropical forest, playing a key role in the global carbon cycle. Thus, understanding climate controls of photosynthetic activity in this region is critical. The establishment of the relationship between photosynthetic activity and climate has been controversial when based on conventional remote sensing-derived indices. Here, we use nine years of solar-induced chlorophyll fluorescence (ChlF) data from the Global Ozone Monitoring Experiment (GOME-2) sensor, as a direct proxy for photosynthesis, to assess the seasonal response of photosynthetic activity to solar radiation and precipitation in Amazonia. Our results suggest that 76% of photosynthesis seasonality in Amazonia is explained by seasonal variations of solar radiation. However, 13% of these forests are limited by precipitation. The combination of both radiation and precipitation drives photosynthesis in the remaining 11% of the area. Photosynthesis tends to rise only after radiation increases in 61% of the forests. Furthermore, photosynthesis peaks in the wet season in about 58% of the Amazon forest. We found that a threshold of ≈1943 mm per year can be defined as a limit for precipitation phenological dependence. With the potential increase in the frequency and intensity of extreme droughts, forests that have the photosynthetic process currently associated with radiation seasonality may shift towards a more water-limited system.We gratefully acknowledge the CAPES and FAPESP (Grants No. 13/14520-6 and No.
2013/50533-5) agencies for providing research fellowships and support this work. L.O.A and L.E.O.C.A thank the
National Council for Scientific and Technological Development (CNPq), for the productivity fellowship, processes
number 309247/2016-0 and 305054/2016-3, respectively. F.H.W. have been funded by the FAPESP (process number
13/14520-6, process number 15/50484-0 and process number 16/17652-9)
Longitudinal Variability in Hydrochemistry and Zooplankton Community of a Large River: A Lagrangian‐Based Approach
The variability in water quality and zooplankton community structure during downstream transport was investigated in the Po river (Italy) using for the first time a Lagrangian sampling approach. Two surveys were conducted, one in spring under relatively high discharge levels, and one at low flows in summer. Twelve stations along a 332‐km stretch of the river’s lowland reach and four major tributaries were sampled. A hydrodynamic modelling system was used to determine water transport time along the river, with a satisfying fit between simulated and observed discharge values. No clear downstream trend in phosphorus and nitrogen concentrations was found. Conversely, a marked longitudinal decrease in dissolved silica supports the hypothesis of increasing downstream silica limitation during the phytoplankton growing season.In spring, at low residence time, no apparent plankton growth was observed during downstream transport. In summer, higher temperatures and lower turbulence and turbidity associated with longer residence time stimulated algal growth and in‐stream reproduction of fast‐growing rotifer taxa, with the gradual downstream development of a truly potamal assemblage and the increase of the ratio of euplanktonic to littoral/epibenthic rotifer taxa. Crustacean zooplankton density was generally low. The importance of biotic interactions within the zooplankton in driving community abundance and composition appeared to increase in the downstream direction, paralleled by a decrease in the influence of physical forcing. Tributary influence was especially evident where severe anthropogenic alterations of river hydrology and trophic status resulted in enhanced plankton growth, ultimately affecting zooplankton structure in the main river. Copyright © 2016 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134064/1/rra3028.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134064/2/rra3028_am.pd
Upadacitinib: One More Option in the Treatment of Patients with Rheumatoid Arthritis and Crohn's Disease
Arthritis and IBD are conditions that can occur in the same patient simultaneously. The complexity
in managing these cases lies in detecting the signs and symptoms that point to the onset of the
disease at an early stage, and in choosing an appropriate course of treatment to control the joint
and intestinal aspects at the same time. In recent times, a new class of drugs has been added to the
treatment options: JAK inhibitors (JAKi), of which Upadacitinib is one. Being able to manage and
follow up with these patients in joint gastro-rheumatology outpatient clinics, where professionals
from both disciplines are able to follow these cases appropriately, avoiding delays in diagnosis andtreatment, is also importan
High-resolution tracking in a GEM-Emulsion detector
SHiP (Search for Hidden Particles) is a beam dump experiment proposed at the
CERN SPS aiming at the observation of long lived particles very weakly coupled
with ordinary matter mostly produced in the decay of charmed hadrons. The beam
dump facility of SHiP is also a copious factory of neutrinos of all three kinds
and therefore a dedicated neutrino detector is foreseen in the SHiP apparatus.
The neutrino detector exploits the Emulsion Cloud Chamber technique with a
modular structure, alternating walls of target units and planes of electronic
detectors providing the time stamp to the event. GEM detectors are one of the
possible choices for this task. This paper reports the results of the first
exposure to a muon beam at CERN of a new hybrid chamber, obtained by coupling a
GEM chamber and an emulsion detector. Thanks to the micrometric accuracy of the
emulsion detector, the position resolution of the GEM chamber as a function of
the particle inclination was evaluated in two configurations, with and without
the magnetic fiel
Antibacterial effects of two synthetic peptides against Enterococcus faecalis biofilms: A preliminary in vitro study
Aim: Current endodontic techniques are unable to fully eradicate intracanal bacteria. Thus, new agents that effectively eliminate endodontic pathogens are needed. The aim of this study was to assess the antibacterial properties of two synthetic peptides, namely KP and L18R, against planktonic cells and biofilms of the endodontic pathogen Enterococcus faecalis. Methodology: KP and L18R bactericidal activity against E. faecalis ATCC 29212 was evaluated by colony forming unit assays and the half maximal effective concentration (EC50) was calculated. The effect of peptides on E. faecalis biofilm formation onto polystyrene plates was also assessed by the crystal violet assay. Confocal laser scanning microscopy (CLSM) analysis was carried out to compare the effects of KP, L18R and a Ca(OH)2 saturated solution in an in vitro model of dental infection consisting in 2-day-old E. faecalis biofilms grown on hydroxyapatite disks. Results: Both KP and L18R showed strong bactericidal activity against planktonic E. faecalis. L18R proved to be 10-folds more ef fective than KP (KP and L18R EC50 values=4.520×10-6 M and 3.624×10-7 M, respectively). Peptides inhibited E. faecalis biofilm formation in a dose-dependent manner and L18R resulted more effectivethan KP. CLSM images showed that Ca(OH)2, KP and L18R remarkably impaired E. faecal is biof i lms pre -grown on hydroxyapatite. Conclusions: KP and L18R effectively inhibited E. faecalis, both in planktonic and biofilm form. L18R demonstrated a more potent antibacterial activity than KP. These preliminary results suggest that antimicrobial peptides may represent a promising new strategy for endodontic infection control
Activity of two antimicrobial peptides against Enterococcus faecalis in a model of biofilm-mediated endodontic infection
Enterococcus faecalis is a common cause of biofilm-associated opportunistic infections, which are often difficult to treat. The formation of E. faecalis biofilms on the dentinal walls of the root canal is frequently the cause of endodontic treatment failure and secondary apical periodontitis. In a preliminary work, two recognized antifungal peptides, KP and L18R, showed antibacterial activity against planktonic E. faecalis cells at micromolar concentrations. Moreover, L18R proved to reduce the biomass in the early stage of E. faecalis biofilm development on polystyrene plates, while a qualitative biofilm inhibition was demonstrated on hydroxyapatite disks by confocal laser scanning microscopy (CLSM). The aim of this study was to better characterize the effect of both peptides on E. faecalis biofilm. A reduction in metabolic activity after peptide treatment was detected by Al-amar Blue assay, while a remarkable impairment in the architecture of E. faecalis biofilms on hy-droxyapatite disks, along with a significant reduction in viable bacteria, was caused mostly by L18R, as assessed by CLSM and scanning electron microscopy. The lack of cytotoxicity of the investigated peptides against L929 murine fibroblasts was also determined. Obtained results suggest L18R as a promising candidate for the development of new strategies for endodontic infection control
Steroids efficacy in the acute management of seizure clusters in one case of PCDH19 female epilepsy
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Diatom extraction: A new technique with heated H2O2. A technical note
The best method of diatom identification in animal and human tissues is still an important discussion topic, in terms of effectiveness and reliability. In this technical note, authors propose a new method of extraction of diatoms using heated hydrogen peroxide from animal and human tissue samples. This method has been compared with the traditional method of digestion with acids. The results of the comparison show that heated hydrogen peroxide extraction is more efficient in terms of reduction of sediment, extraction of the material and preservation of diatoms proving to be a viable alternative to conventional approaches with acids in terms of costs and operator safety
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