The influence of partial composite action between concrete slab and steel beam and of partial-strength connections on the seismic response of composite frames is evaluated. To this end, experimental ...tests were carried out at the Laboratory of the National Technical University of Athens. The specimens, one-story one-bay moment-resisting frames with steel–concrete composite beams, were tested under base acceleration on the shaking table. Experimental results demonstrated that for different degrees of partial interaction between the slab and the beam the response of the specimens varied significantly. Specimens with intermediate and low shear connection degree showed the most favourable performance, in terms of ductile behavior and energy dissipation. The slip between the slab and the beam interface contributed to the energy dissipated by the system and the ductility demands decreased on other parts like the beam ends and the joints. Then, finite element models simulating the behavior of the tested specimens were developed and, after validation, extended parametric studies were carried out. The main objective is to investigate the influence of the partial interaction and the employment of partially restrained beam-to-column joints on the dissipative capacities of composite frames under strong ground motions. Numerical results confirmed the experimental conclusions and revealed that the use of intermediate and low shear connection degrees with partial-strength joints results in an advantageous seismic design.
•Modified QuEChERS approach for extraction of 3-MCPD diesters in edible oils.•Clean-up based on d-SPE was tested using Si-SAX, Z-sep+ and PSA as sorbents.•Validation of LC–MS/MS method to determine ...seven 3-MCPD diesters using FDA guideline.•3-MCPD diesters in 12 edible oils and 2 margarine samples was determined.
A fast and effective method using a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) approach which includes partitioned liquid-liquid extraction (PLLE) and dispersive solid phase extraction (dSPE) clean-up step for the determination of seven 3-monochloropropane-1,2-diol (3-MCPD) fatty acid diesters in vegetable oils is developed and validated according to the Food and Drug Administration (FDA) guidelines. Due to the complexity of the matrices, combination of silica based sorbents (Silica Strong Anion Exchange (Si-SAX), Supel™ QuE Z-Sep+ (Z-Sep+) and Primary Secondary Amine (PSA) were tested for lipid removal. The effect of several experimental factors on the efficiency of the extraction procedure was studied by a screening design 3422//16 and a response surface Doehlert design. The separation and determination was carried out by liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS). The method provided suitable linearity (r2 > 0.9960), precision (relative standard deviation (RSD) lower than 10%) and accuracy, in terms of recovery. The limits of detection (LOD) and limits of quantification (LOQ) ranged from 10 to 20 μg kg −1 and from 25 to 50 μg kg−1, respectively. The recoveries at three spiking levels of 100, 250, and 500 μg kg−1 were over the range of 71.4–122.9% with RSD lower than 13%. The method was successfully applied in edible oils and fatty food samples. The results provide valuable information to assess the risk of exposure to these foodborne contaminants.
A growth trial was conducted to test three isonitrogenous diets (59% crude protein, dry matter basis) for Senegalese sole during the ongrowing stage. A control diet (S-15) based on a commercial diet ...for sole (15% crude fat, 23
kJ
g
−1 energy) was compared with a plant protein based diet (S-15PP) with similar energy content. This plant-based diet was supplemented with arginine, threonine, methionine and lysine to reach the levels of the S-15 diet. A low-energy diet, S-8, was formulated with the very same feed ingredients as S-15, but dietary fish oil was reduced (8% crude fat, 21
kJ
g
−
1
). Triplicate groups of 20 fish with a mean initial body weight of 180
g were reared at 19
°C and fed the experimental diets using automatic feeders that distributed 4 meals a day, during 8
months. At the end of the experiment all groups reached commercial size (>
300
g). Dietary treatments did not affect mean final body weight. Daily growth index was generally low (0.4–0.5) and feed conversion ratio (FCR, range 2.5–2.9) did not vary significantly between treatments. Fish fed S-8 ingested fewer lipids, but its whole body or tissue lipid was equal to fish fed the S-15 and the S-15PP diets. Sole fed the S-15PP diet showed reduced plasma taurine and increased liver vacuolisation due to excess lipid storage. This diet also induced the highest Hepatosomatic index (HSI) and viscerosomatic index (VSI). Muscle, liver or skin total lipid content did not vary significantly amongst treatments. Whole body lipid content and plasma triglycerides were significantly lower in the S-15PP than in the S-15, and cholesterol showed the same trend. Protein gain (23–27
g/kg/day), whole body protein content (18–19% wet weight) and muscle protein content (19%) were not affected by the dietary treatments. Results indicate that replacement of dietary fish meal by a mixture of plant protein sources did not adversely affect growth, feed or protein utilisation of large-sized sole, but increased vacuolization and necrosis signs in hepatocytes. This could probably be avoided by an addition of taurine in the high PP diets. The cardiovascular protection and health beneficial properties associated with fish consumption can be achieved with sole either fed low-fat diets or plant protein based-diets, as confirmed by the still high levels of
n-
3 and DHA registered in the flesh of those fish.
Diffusion of ferric ions in ferrous sulfate (Fricke) gels represents one of the main drawbacks of some radiation detectors, such as Fricke gel dosimeters. In practice, this disadvantage can be ...overcome by prompt dosimeter analysis, and constraining strongly the time between irradiation and analysis, implementing special dedicated protocols aimed at minimizing signal blurring due to diffusion effects. This work presents a novel analytic modeling and numerical calculation approach of diffusion coefficients in Fricke gel radiation sensitive materials. Samples are optically analyzed by means of visible light transmission measurements by capturing images with a charge-coupled device camera provided with a monochromatic filter corresponding to the XO-infused Fricke solution absorbance peak. Dose distributions in Fricke gels are suitably delivered by assessing specific initial conditions further studied by periodical sample image acquisitions. Diffusion coefficient calculations were performed using a set of computational algorithms based on inverse problem formulation. Although 1D approaches to the diffusion equation might provide estimations of the diffusion coefficient, it should be calculated in the 2D framework due to the intrinsic bi-dimensional characteristics of Fricke gel layers here considered as radiation dosimeters. Thus a suitable 2D diffusion model capable of determining diffusion coefficients was developed by fitting the obtained algorithm numerical solutions with the corresponding experimental data. Comparisons were performed by introducing an appropriate functional in order to analyze both experimental and numerical values. Solutions to the second-order diffusion equation are calculated in the framework of a dedicated method that incorporates finite element method. Moreover, optimized solutions can be attained by gradient-type minimization algorithms. Knowledge about diffusion coefficient for a Fricke gel radiation detector is helpful in accounting for effects regarding elapsed time between dosimeter irradiation and further analysis. Hence, corrections might be included in standard dependence of optical density differences and actual, non-diffused, absorbed dose distributions. The obtained values for ferric ion diffusion coefficient are around 0.65 mm
2
h
−1
, being in good agreement with previous works corresponding to similar Fricke gel dosimeter compositions. Therefore, more accurate 2D and 3D dose mapping might be attained, thus constituting valuable improvements in Fricke gel dosimetry, and parallely a high precision method of diffusion modeling and calculation has been developed.
Abstract Heterozygous mutations in the PINK1 gene are considered a susceptibility factor to develop early-onset Parkinson's disease (PD), as supported by dopamine hypometabolism in asymptomatic ...mutation carriers and subtle alterations of dopamine-dependent striatal synaptic plasticity in heterozygous PINK1 knockout (PINK1+/− ) mice. The aim of the present study was to investigate whether exposure to low-dose rotenone of heterozygous PINK1+/− mice, compared to their wild-type PINK1+/+ littermates, could impact on dopamine-dependent striatal synaptic plasticity, in the absence of apparent structural alterations. Mice were exposed to a range of concentrations of rotenone (0.01–1 mg/kg). Chronic treatment with concentrations of rotenone up to 0.8 mg/kg did not cause manifest neuronal loss or changes in ATP levels both in the striatum or substantia nigra of PINK1+/− and PINK1+/+ mice. Moreover, rotenone (up to 0.8 mg/kg) treatment did not induce mislocalization of the mitochondrial membrane protein Tom20 and release of cytochrome c in PINK1+/− striata. Accordingly, basic electrophysiological properties of nigral dopaminergic and striatal medium spiny neurons (MSNs) were normal. Despite the lack of gross alterations in neuronal viability in chronically-treated PINK1+/− , a complete loss of both long-term depression (LTD) and long-term potentiation (LTP) was recorded in MSNs from PINK1+/− mice treated with a low rotenone (0.1 mg/kg) concentration. Even lower concentrations (0.01 mg/kg) blocked LTP induction in heterozygous PINK1+/− MSNs compared to PINK1+/+ mice. Of interest, chronic pretreatment with the antioxidants alpha-tocopherol and Trolox, a water-soluble analog of vitamin E and powerful antioxidant, rescued synaptic plasticity impairment, confirming that, at the doses we utilized, rotenone did not induce irreversible alterations. In this model, chronic exposure to low-doses of rotenone was not sufficient to alter mitochondrial integrity and ATP production, but profoundly impaired the expression of long-term plasticity at corticostriatal synapses in PINK1 heterozygous knockout mice, suggesting that disruption of synaptic plasticity may represent an early feature of a pre-manifesting state of the disease, and a potential tool to test novel neuroprotective agents.
To be able to study nutrient requirement and utilization in any species, a diet supporting normal feed intake and growth equally well as a traditional fish meal-based diet is needed. Additionally the ...formulation of the diet should allow low levels of the nutrient under study. When studying the amino acid metabolism and requirements, one cannot rely on the fish meal-based diets as fish meal are nicely balanced according to requirements. Therefore the current study aimed to develop a plant protein-based diet (with low fish meal inclusion) to be used in the nutritional studies of Senegalese sole juveniles supporting feed intake and growth close to that obtained in a fish meal-based control feed. Two experiments were conducted to evaluate whether Senegalese sole juveniles would accept and utilize diets containing high plant protein inclusion. For testing the acceptance of high plant protein inclusion, two diets were formulated: a reference diet that contained fish meal as the main protein source (450 g kg⁻¹ dry matter) whereas in the test diet, fish meal was substituted by a mixture of plant ingredients (soybean meal, corn and wheat gluten) with l-lysine supplementation. In order to improve the palatability, 50 g kg⁻¹ squid meal was added to both diets. The indispensable amino acids (IAA) profile of the test diet was made similar to the control diet by adding crystalline amino acids. Further, automatic feeders were used to improve the feed intake. Fish (24 g initial body weight) were fed the diets for a period of 4 weeks. As fish accepted both diets equally well, a second study was undertaken to test the growth performance. Fish (6 g initial BW) were fed the diets for a period of 12 weeks. The use of automatic feeders to deliver the feed and the addition of both squid and balancing the indispensable amino acids resulted in growth performance and accretion not differing from the fish meal fed control. It can be concluded that juvenile Senegalese sole are able to grow and utilize high plant-protein diets when both diet composition and feeding regime are adequate for this species.
Glass system of composition (50−x)TeO2–5Sb2O3–45B2O3: xMnO with ‘x’ ranging from 0.3 to 1.5mol% has been prepared via melt quenching followed by controlled crystallization. Further, the samples were ...characterized by X-ray diffraction, scanning electron microscopy and DSC techniques. A number of studies viz., optical absorption, EPR, and luminescence of these glass ceramics have been carried out. The spectroscopic studies have confirmed the existence of manganese ions in trivalent state in addition to divalent. EPR spectra of all investigated glass ceramics exhibit resonance signals that are characteristic for Mn2+ ions. The changes found in all the properties as function of the crystallizing agent (MnO) have been discussed in detail.
► High rigid TeO2–Sb2O3–B2O3: MnO glass ceramics are synthesized and characterized. ► Optical absorption spectra exhibit bands due to Mn2+ and traces of Mn3+ ions also. ► EPR spectra exhibit a resonance signal with effective g at 2.02. ► Gradual transformation of Mn ions from tetragongal to octahedral environment is observed.
Tissue paper was the only paper grade whose consumption increased during 2020 in Europe. In a highly competitive context, this work explores a strategy based on bisacrylamide cross-linkers and ...poly(vinyl alcohol) (PVA), seeking to enhance the water uptake of pulps for tissue paper and the key properties of the resulting tissue sheets: water absorption capacity, capillarity, softness, porosity, and strength. For that, α-cellulose from cotton and a kraft hardwood pulp, in parallel, were reacted with
N,N’
-methylenebisacrylamide, both in the absence and in the presence of PVA. The water desorption rate of the modified polymers was monitored. Pulp blends were then mixed with a conventional softwood pulp (30%) to prepare laboratory tissue paper sheets (20 g m
–2
). For cotton cellulose, cross-linking with PVA more than doubled the water uptake, up to 7.3 g/g. A significant enhancement was also obtained in the case of pulps, up to 9.6 g/g, and in the case of paper, to 11.9 g/g. This improvement was consistent with a drastic increase in porosity, and it was not detrimental to paper strength.
Graphical Abstract
Experimental tests and numerical analyses were carried out to study the seismic behavior of semi-rigid partial-strength steel–concrete composite beam-to-column joints. First, a detailed description ...of the experimental program and the main results of the experimental tests were presented. Four full-size sub-assemblages representing exterior composite beam-to-column joints were tested under cyclic loading at the Laboratory of the Politecnico di Milano. The specimens exhibited large dissipative capacities and very stable and ductile behavior without significant reduction in strength and stiffness. The hysteretic behavior and the dominant failure modes of the tested sub-assemblages, the contribution of the column web panel to the overall joint rotations and the mechanisms which may describe the force transfer between concrete slab and column were analyzed and discussed. Then, finite element models of the tested specimens were developed and numerical analyses were carried out in order to further investigate the stress state in the composite sub-assemblages and to study the influence of various parameters on the joint behavior. The influence of the slab contribution, the mechanisms of force transfer in the slab in the connection zone, the effect of the degree of partial interaction and the stress field existing in the slab for various layout of seismic rebars were studied.
