Statistical event reconstruction techniques can give better results for gamma cameras than the traditional centroid method. However, implementation of such techniques requires detailed knowledge of ...the photomultiplier tube light-response functions. Here we describe an iterative method which allows one to obtain the response functions from flood irradiation data without imposing strict requirements on the spatial uniformity of the event distribution. A successful application of the method for medical gamma cameras is demonstrated using both simulated and experimental data. An implementation of the iterative reconstruction technique capable of operating in real time is presented. We show that this technique can also be used for monitoring photomultiplier gain variations.
Although Quercetin absorbs in the UVA/UVB electromagnetic region, it is limited for applications as a UV filter due to its low lipophilicity and capacity to penetrate the epidermis. In order to ...overcome this limitation, we synthetized and evaluated the photo protective properties of a derivative obtained from Quercetin. The derivative was prepared by alkylation of Quercetin with iodoethane and characterized by IR and NMR spectroscopy. The in vitro Solar Protection Factor was determined by the Mansur method and the cytotoxicity was evaluated using hepatocellular cell (Hep G2) cells. Finally, Quercetin and the corresponding derivative were incorporated in nanoemulsions. Nanoemulsions with particles sizes between 53 and 73 nm were obtained, and polydispersity indexes were around 0.1, indicating good homogeneity of the nanoemulsion particles. The cell viability study for the Quercetin derivative indicated a very low cytotoxicity profile. The chemical modification of Quercetin resulted in a promising compound with improved properties desirable for skin penetration and incorporation into sunscreen formulations.
Measuring ammonia (NH3) volatilization from urea-fertilized soils is crucial for evaluation of practices that reduce gaseous nitrogen (N) losses in agriculture. The small area of chambers used for ...NH3 volatilization measurements compared with the size of field plots may cause significant errors if inadequate sampling strategies are adopted. Our aims were: i) to investigate the effect of using multiple open chambers on the variability in the measurement of NH3 volatilization in urea-amended field plots and ii) to define the critical period of NH3-N losses during which the concentration of sampling effort is capable of reducing uncertainty. The use of only one chamber covering 0.015% of the plot (51.84 m2) generates a value of NH3-N loss within an expected margin of error of 30% around the true mean. To reduce the error margin by half (15%), 3–7 chambers were required with a mean of 5 chambers per plot. Concentrating the sampling efforts in the first two weeks after urea application, which is usually the most critical period of N losses and associated errors, represents an efficient strategy to lessen uncertainty in the measurements of NH3 volatilization. This strategy enhances the power of detection of NH3-N loss abatement in field experiments using chambers.
•We model experimentally and numerically a gully box.•We simulate turbulence with LES Smagorinsky using the OpenFOAM toolbox.•Reverse flow shows strong jet at the center and an anticlockwise vortex ...on the left side.•Drainage flow shows a clockwise vortex above and to the left of the bottom outlet.•Drainage flow exhibits large quantities of air-entrainment caused by a hydraulic jump.
Gullies are devices that connect the surface system to the sewer allowing the drainage of water during a rainfall event. During severe flooding, the sewer might become pressurized and water may gush out of the sewer onto the surface, in what is termed reverse flow. Experimental and numerical studies of gullies are rare because of the high computational time and the experimental facilities costs. In this paper we aim to characterize the average velocity inside a gully at the center profile and discuss the qualitative air-entrainment structure for both drainage and reverse flow conditions. The experimental facility termed the Multiple-Linking-Element experiment (MLE) is located at the University of Coimbra. OpenFOAM™ v.1.7.1 is used with the Large Eddy Simulation (LES) Smagorinsky model to simulate turbulence. Numerical and experimental results show reverse flow with a strong jet at the center and an anticlockwise vortex on the left side of the gully box, and drainage flow with a large clockwise vortex located above and slightly to the left of the bottom outlet. Reverse flow shows few traces of air-entrainment, unlike drainage flow that exhibits large quantities of air-entrainment caused by a hydraulic jump formed on the surface flow.
The populations of group B streptococcus (GBS) associated with vaginal carriage in pregnant women and invasive neonatal infections in Portugal were compared. GBS isolates were characterized by ...serotyping, pulsed-field gel electrophoresis (PFGE) profiling, and multilocus sequence typing (MLST). Serotypes III and V accounted for 44% of all colonization isolates (n = 269), whereas serotypes III and Ia amounted to 69% of all invasive isolates (n = 64). Whereas serotype Ia was associated with early-onset disease (EOD), serotype III was associated with late-onset disease (LOD). Characterization by PFGE and MLST identified very diverse populations in carriage and invasive disease. Serotype Ia was represented mainly by a single PFGE cluster defined by sequence type 23 (ST23) and the infrequent ST24. In contrast, serotype III was found in a large number of PFGE clusters and STs, but a single PFGE cluster defined by ST17 was found to be associated with invasive disease. Although serotype III was associated only with LOD, ST17 showed an enhanced capacity to cause both EOD and LOD. Our data reinforce the evidence for enhanced invasiveness of ST17 and identify a lineage expressing serotype Ia capsule and represented by ST23 and ST24 as having enhanced potential to cause EOD.
Some organic recalcitrant compounds are not degraded by conventional water treatment systems, making necessary the use of advanced technologies to eliminate these substances. Advanced Oxidation ...Processes (AOPs) have been extensively proposed to remove emerging contaminants aiming potable water reuse, but literature barely addresses neurotoxic effects of AOPs residual byproducts. These processes involve high costs associated with the electricity, maintenance and oxidizing agent used. However, electrochemical AOPs are techniques based on electron transfer, thus being a clean form of energy and very efficient in the degradation of organic pollutants. Parabens are naturally found in plant sources but most are chemically synthesized, requiring careful treatment to not disturb the environment. In this study, a mixture of parabens (10 mg L-1 each) was degraded by an electrochemical oxidation (EO) system with a Ti/Pt anode. Some parameters, such as the current density (25, 75 and 125 A m-2) and the electrolyte type and concentration (1.5, 3.0 and 5.0 g NaCl L-1 and 3.0 g Na2SO4 L-1) were changed. The best results were obtained with 125 A m-2 and 3.0 g NaCl L-1, which led to the complete degradation of the parabens present in the mixture, after 10 min. In addition to these studies neurotoxicity tests were also performed using the solutions of interest, before and after the EO treatment. It was observed, using the reactive oxygen species (ROS) fluorescent indicator H2DCFDA, that the non-treated solution caused an increase in ROS formation with a signal amplitude of 0.84 ± 0.20 above the baseline. After the EO process the parabens mixture did not lead to a significant ROS change. The solution to bridge the problem of high electricity costs may be replacing it with solar energy, low cost catalysts and other treatment processes involving renewable and eco-friendly energy.
The relationship between the Mn content and the cyclic deformation behaviour in bainitic rail steels is not yet clearly understood. The aim of this paper is, therefore, to study the cyclic plastic ...response of bainitic rail steels with different Mn contents. In order to meet these goals, low-cycle fatigue tests under fully-reversed strain-controlled conditions are performed at strain amplitudes in the range of 0.6 to 1.0%. The microstructure is analysed by TEM, SEM and XRD, and fracture surfaces are examined by SEM. The results show that the cyclic stress-strain response is significantly affected by the Mn addition. The steel without Mn initially strain hardens and then strain softens until final failure, while the steels with Mn content have an initial stage of strain hardening followed by saturation. Concerning the fatigue response, the addition of Mn is detrimental under higher strain amplitudes but, on the contrary, leads to longer lives under lower strain amplitudes. The fatigue response is explained by the different microstructure morphologies associated with the Mn alloying element.
Due to environmental and social conditions inherent to incarceration, tuberculosis (TB) and hepatitis B virus (HBV) are major diseases among prison inmates.
To determine overall and occult HBV ...infection (OBI) prevalence rates, risk factors and genotype distribution among inmates with active TB.
A cross-sectional study was conducted among 216 inmates with active TB recruited at the largest prisons in Campo Grande, Mato Grosso do Sul, Central Brazil. The participants were interviewed and tested for the presence of serological markers for HBV infection.
The overall prevalence of HBV infection (total hepatitis B core antibodies) was 10.2% (95%CI 6.2-14.2). HBV surface antigen (HBsAg) prevalence was 1.4% (3/216). HBV DNA was detected in all three HBsAg-positive samples and in 10.5% (2/19) of the anti-HBc-positive samples (OBI), giving a HBV-TB co-infection prevalence of 2.3% (5/216). A multivariate analysis of risk factors showed that history of sharing cutting instruments, length of incarceration and homosexual sex were associated with HBV infection.
Our findings indicate that HBV remains an important public health concern among prison inmates and active TB-HBV co-infection needs to be addressed for effective treatment.
Aim
To test the effects of a mineral trioxide aggregate‐based sealer (MTA Fillapex®) and MTA (MTA‐Ângelus®) on viability and on the production of cytokines, reactive oxygen species (ROS) and nitrogen ...species (NO) by M1 and M2 inflammatory macrophages.
Methodology
M1 (from C57BL/6 mice) and M2 (from BALB/c mice) peritoneal inflammatory macrophages were obtained and cultured in vitro in the presence of original and diluted extracts of MTA and MTA Fillapex (FLPX). The cell viability, ROS release and the release of tumour necrosis factor‐a, interleukin (IL)‐12, IL‐10 and NO in response to stimulation with interferon‐γ and Fusobacterium nucleatum or Peptostreptococcus anaerobius were evaluated. The data were analysed using the Mann–Whitney test and Student's t‐test.
Results
Fillapex was cytotoxic at the highest concentrations (1 : 1;1 : 2) and decreased the viability (P < 0.05) of both macrophage types (<20%). MTA did not interfere with cellular viability. FLPX inhibited the release of ROS and decreased NO release in F. nucleatum and P. anaerobius ‐stimulated M1 and M2 macrophages (≤25 μ mol L–1). F. nucleatum–stimulated M2 macrophage cultures released lower levels of TNF‐α when FLPX was added (≤1 ng mL−1). M2 macrophages released higher (>5 ng mL−1) levels of IL‐10 than M1 macrophages. Only M1 macrophage cultures produced IL‐12p70.
Conclusions
Fillapex impaired effector immune responses during inflammation (M1 macrophages), as well as during healing (M2 macrophages) responses.
This paper presents a homogenization-based theory for three-dimensional anisotropic beams. The proposed beam theory uses a hierarchy of solutions to carefully-chosen beam problems that are referred ...to as the fundamental states. The stress and strain distribution in the beam is expressed as a linear combination of the fundamental state solutions and stress and strain residuals that capture the parts of the solution not accounted for by the fundamental states. This decomposition plays an important role in the homogenization process and provides a consistent method to reconstruct the stress and strain distribution in the beam in a post-processing calculation. A finite-element method is presented to calculate the fundamental state solutions. Results are presented demonstrating that the stress and strain reconstruction achieves accuracy comparable with full three-dimensional finite element computations, away from the ends of the beam. The computational cost of the proposed approach is three orders of magnitude less than the computational cost of full three-dimensional calculations for the cases presented here. For isotropic beams with symmetric cross-sections, the proposed theory takes the form of classical Timoshenko beam theory with Cowper’s shear correction factor and additional load-dependent corrections. The proposed approach provides an extension of Timoshenko’s beam theory that handles sections with anisotropic construction.
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