This paper addresses the buckling and vibration analysis of isotropic and laminated plates by a first-order shear deformation theory. The numerical approach is based on collocation with radial basis ...functions. The model allows the analysis of arbitrary boundary conditions and irregular geometries. It is shown that the present method, based on a first-order shear deformation theory produces highly accurate natural frequencies and modes of vibration, as well as critical loads and modes.
The capability to produce blend chitosan–whey protein films at acidic pH, carrying a high amount of protein, is demonstrated, even though under these conditions a pure whey protein film could not be ...obtained. The films are biphasic and characterized by a compositional gradient, with the downward film surface containing a lower amount of protein than the upward surface. The surface richer in protein was more hydrophobic than that richer in chitosan. The difference in composition and hydrophilicity between both surfaces increases with the amount of protein incorporated in the film. Increasing the protein amount decreased elongation at break and tensile strength but, in general, had little effect on water vapor permeability. Although some of the film functionality might be compromised due to the incompatibility between the polysaccharide and protein components within the film matrix, the blended films, especially those with intermediated protein amount, may have useful applications on those food systems where the edible films should break up during the cooking or mastication process.
Wetland soils, especially those under a semi-arid climate, are among the least studied soils in the tropics. The hypersaline tidal flats on the north-eastern Brazilian coast, locally named apicum, ...are coastal wetland ecosystems in the peripheral portions of semi-arid estuaries. Despite their great ecological importance, they have been highly impacted by anthropogenic activities. Morphological and analytical data of six soil profiles, representative of the different coastal compartments (mangroves, apicum and coastal tablelands) of the north-eastern Brazilian coast, were examined to better understand the pedogenesis of apicum soils. The hypersaline tidal flat soils were classified as Typic Fluvaquents and Typic Sulfaquents with the following main characteristics: predominance of sand fraction (62–77%); presence of high-activity clays (>24cmolckg-1 clay); clay fraction comprising kaolinite, illite, smectite and an interstratified smectite/illite; exchangeable complex dominated by Na+ (ESP ≥15%); elevated levels of salinity (electrical conductivity, EC 25–44dSm-1); alkaline pH values (7.5–9.5). The sandy texture and quartz-dominated composition of the hypersaline, tidal flat soils indicate a pedogenesis associated with the superficial addition of mineral material. This upbuilding process would have lowered the watertable (relatively to the ground level) and decreased the flooding frequency by the tides, favouring salinisation and solonisation processes at the hypersaline tidal flats. Furthermore, the still-existing hydromorphism would have promoted the maintenance of gleisation and sulfidisation. The presence of pyrite on the hyper-saline tidal flat soils further corroborates the formation of apicum soils from/over buried mangroves.
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•Temperature dependence on the vibrational properties of the K2Mo2O7·H2O.•Temperature-induced phase transformation in the K2Mo2O7·H2O.•Electronic properties of the K2Mo2O7·H2O ...semiconductor material.•Lattice dynamic calculations based on the density-functional theory (DFT).
This study reports a temperature-dependent Raman scattering and X-ray diffraction study of K2Mo2O7·H2O. The high-temperature Raman scattering analysis shows that the material remains structurally stable, with triclinic symmetry, in a temperature range from 300 to 413 K and undergoes a structural phase transition between 413 and 418 K. This phase transition is most likely connected with the dehydration process of K2Mo2O7·H2O. The temperature-dependent X-ray diffraction patterns are measured from 30 to 573 K. The results show that the discovered phase transition occurs between 419 and 433 K, in good agreement with the Raman scattering results. According to the Raman data, with increasing temperature, the dehydrated crystal of K2Mo2O7 undergoes a new phase transformation at 603 K and melts at ~843 K. Principal component and hierarchical cluster analyses are performed based on the treatment of the raw spectral data to infer the phase transformations occurring in the material. Assignments of the Raman modes for the K2Mo2O7 system at ambient conditions are studied through first-principles calculations based on density functional perturbation theory. These calculations are applied to understand the electronic properties, including the band structure and the associated projected density of states, of K2Mo2O7 under the local density approximation.
Abstract
Objective
This study proposes to present reference parameters for trigeminal (V) and facial (VII) cranial nerves (CNs)-triggered electromyography (tEMG) during endoscopic endonasal approach ...(EEA) skull base surgeries to allow more precise and accurate mapping of these CNs.
Study Design
We retrospectively reviewed EEA procedures performed at the University of Pittsburgh Medical Center between 2009 and 2015. tEMG recorded in response to stimulation of CN V and VII was analyzed. Analysis of tEMG waveforms included latencies and amplitudes. Medical records were reviewed to determine the presence of perioperative neurologic deficits.
Results
A total of 28 patients were included. tEMG from 34 CNs (22 V and 12 VII) were analyzed. For CN V, the average onset latency was 2.9 ± 1.1 ms and peak-to-peak amplitude was 525 ± 436.94 μV (
n
= 22). For CN VII, the average onset latency and peak-to-peak amplitude were 5.1 ± 1.43 ms and 315 ± 352.58 μV for the orbicularis oculi distribution (
n
= 09), 5.9 ± 0.67 ms and 517 ± 489.07 μV on orbicularis oris (
n
= 08), and 5.3 ± 0.98 ms 303.1 ± 215.3 μV on mentalis (
n
= 07), respectively.
Conclusion
Our data support the notion that onset latency may be a feasible parameter in the differentiation between the CN V and VII during the crosstalk phenomenon in EEA surgeries but the particularities of this type of procedure should be taken into consideration. A prospective analysis with a larger data set is necessary.
Single-stage and multi-stage strategies have been evaluated and compared for the purification of human antibodies using liquid–liquid extraction in aqueous two-phase systems (ATPSs) composed of ...polyethylene glycol 3350 (PEG 3350), dextran, and triethylene glycol diglutaric acid (TEG-COOH). The performance of single-stage extraction systems was firstly investigated by studying the effect of pH, TEG-COOH concentration and volume ratio on the partitioning of the different components of a Chinese hamster ovary (CHO) cells supernatant. It was observed that lower pH values and high TEG-COOH concentrations favoured the selective extraction of human immunoglobulin G (IgG) to the PEG-rich phase. Higher recovery yields, purities and percentage of contaminants removal were always achieved in the presence of the ligand, TEG-COOH. The extraction of IgG could be enhanced using higher volume ratios, however with a significant decrease in both purity and percentage of contaminants removal. The best single-stage extraction conditions were achieved for an ATPS containing 1.3% (w/w) TEG-COOH with a volume ratio of 2.2, which allowed the recovery of 96% of IgG in the PEG-rich phase with a final IgG concentration of 0.21
mg/mL, a protein purity of 87% and a total purity of 43%. In order to enhance simultaneously both recovery yield and purity, a four stage cross-current operation was simulated and the corresponding liquid–liquid equilibrium (LLE) data determined. A predicted optimised scheme of a counter-current multi-stage aqueous two-phase extraction was hence described. IgG can be purified in the PEG-rich top phase with a final recovery yield of 95%, a final concentration of 1.04
mg/mL and a protein purity of 93%, if a PEG/dextran ATPS containing 1.3% (w/w) TEG-COOH, 5 stages and volume ratio of 0.4 are used. Moreover, according to the LLE data of all CHO cells supernatant components, it was possible to observe that most of the cells supernatant contaminants can be removed during this extraction step leading to a final total purity of about 85%.
•Non Fickian mathematical model for glioma growth.•Non Fickian behavior is induced by the viscoelasticity of the brain tissue.•Chemotherapy protocols that lead to the reduction of tumor mass.•Non ...Fickian discrete model that mimics the continuous one.•Numerical experiments showing the effectiveness of the approach.
In this paper we propose a mathematical model to describe the evolution of glioma cells taking into account the viscoelastic properties of brain tissue. The mathematical model is established considering that the glioma cells are of two phenotypes: migratory and proliferative. The evolution of the migratory cells is described by a diffusion–reaction equation of non Fickian type deduced considering a mass conservation law with a non Fickian migratory mass flux. The evolution of the proliferative cells is described by a reaction equation. A stability analysis that leads to the design of efficient protocols is presented. Numerical simulations that illustrate the behavior of the mathematical model are included.
The present study was designated to evaluate the antileishmanial activity of acid and basic fractions that were obtained after acid-basic extraction, from ethanolic 70% crude extract and pure ...compounds from the stem bark of
Aspidosperma ramiflorum. The basic alkaloidal fraction presented a good activity against the extracellular form (promastigotes) of
Leishmania (L.)
amazonensis (LD
50 value<47
μg/ml). Based on these findings, the basic fraction was fractionated on silica gel column chromatography in a bioassay-guided fractionation affording individual purified ramiflorines A and B. Both ramiflorines A and B showed significant activity against
Leishmania (L.)
amazonensis (LD
50 values of 16.3±1.6
μg/ml and 4.9±0.9
μg/ml, respectively). Our results are promising, showing that these compounds are biologically active against Gram-positive bacteria.
This paper studies the multiaxial fatigue behaviour of maraging steel samples produced by selective laser melting. Hollow cylindrical specimens with transverse circular holes are subjected to ...different in-phase bending-torsion loading scenarios. Fatigue crack initiation sites and fatigue crack angles are predicted from the first principal stress field. Fatigue lifetime is computed using a straightforward approach, based on a one-parameter damage law, developed via uniaxial low-cycle fatigue tests. The cyclic plasticity at the notch-controlled process zone is accounted for by combining the equivalent strain energy density concept and the theory of critical distances within a linear-elastic framework. Regardless of the multiaxial loading scenario, experimental observations and predicted lives are very well correlated.
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•Multiaxial fatigue behaviour was significantly affected by the bending moment to the torsion moment ratio.•Un-melted regions at surface and subsurface were the main cause of fatigue crack initiation at the notch.•Fatigue crack initiation sites and fatigue crack angles were predicted from the first principal stress field.•Multiaxial fatigue life was successfully predicted using an uniaxial one-parameter damage law.
Polycyclic aromatic hydrocarbons (PAHs) are organic compounds ubiquitous in the environment and known for their toxic, mutagenic, and carcinogenic effects. These compounds can bioaccumulate in the ...biota and be transferred through trophic webs. The franciscana dolphin (Pontoporia blainvillei), as top predators, can be an environmental sentinels. Thus, this study aimed to provide data about PAHs concentration in their hepatic tissue collected on the coast of Espírito Santo (Franciscana Management Area, FMA Ia), Rio de Janeiro (FMA IIa), and São Paulo states (FMA IIb), in Southeastern Brazil. PAHs were detected in 86 % of franciscana dolphins (n = 50). The highest ∑PAHsTotal median concentration was reported in FMA Ia followed by FMA IIb and FMA IIa (1055.6; 523.9, and 72.1 ng.g-1 lipid weight, respectively). Phenanthrene was detected in one fetus and two neonates, showing maternal transfer of PAHs in these dolphins. Evaluating PAHs with potential toxic effects is of utmost importance for the conservation of a threatened species.
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•PAHs were detected in 86 % (43/50) of franciscana dolphins analyzed.•Naphthalene, fluorene, phenanthrene, and pyrene were the most frequent compounds.•The potential carcinogenic benzo(a)pyrene was detected in 26 % (13/50) of franciscanas.•Maternal transfer of PAHs to one fetus and two neonates was evidenced.•Mutagenic and carcinogenic PAHs are another threat to a critically endangered species.
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