•Sunflower- and soybean-based biodiesels were synthesized by transterification.•Stability to oxidation was determined using ASTMD 7545 method.•Ionol BF 200 was and effective inhibitor for biodiesel ...oxidation.•Antioxidant oxidation kinetics was of first order for soybean biodiesel.•Oxidation kinetics was apparently of zero-order for sunflower biodiesel.
The oxidation stability of biodiesels obtained from the transesterification of sunflower and soybean refined oils was studied using a method of accelerated oxidation (under 700kPa oxygen atmosphere), the so-called PetrOXY method. The antioxidant Ionol BF 200 was used in a concentration range from 0 to 5000ppm, and the experiments were carried out with temperatures varying from 130 to 145°C. Oxidation kinetics could be described with a good precision, considering that correlation coefficients were above 0.99, obeying a first-order reaction kinetics in relation to the concentration of antioxidant for soybean biodiesel and an apparently zero-order kinetics for sunflower biodiesel (which was the result of mathematical approximations derived from a more chemically appropriated first-order kinetics). Reaction specific velocities were determined and enthalpies of activation for antioxidant oxidation were determined from Arrhenius plots. All the results indicated that, for the same inhibitor concentration, sunflower-derived biodiesel was less stable towards oxidation than the soybean one.
•Bi1-xYbxFeO3 system were obtained by the solid-state method.•The compounds crystallize in the rhombohedral phase with space group R3c (161).•For the sample with x = 0.02, the transition from ...paramagnetic to antiferromagnetic state is observed at a Néel temperature of ∼120 K.•The insulating nature of the samples was confirmed through DC resistivity measurements.•Unsaturated hysteresis loops in electric polarization were observed, with a notable impact from leakage currents.
This work reports the effect of Yb3+ substitution on the structural, magnetic, and electrical properties of the Bi1-xYbxFeO3 system (x = 0.00, 0.02, 0.04, 0.05 and 0.06) synthesized via the solid-state reaction method. Structural properties at room temperature were studied by means of XRD diffraction. The XRD pattern were analyzed using Rietveld refinement. The results showed that the Bi1-xYbxFeO3 samples mainly crystallize in rhombohedral phase with space group R3c (161). Magnetic measurements as a function of temperature showed two magnetic behaviors, the first for x < 0.05 and the second one for x < 0.06. From the DC resistivity measurements, the insulating nature of the samples was verified. The electrical behavior of the compounds was also investigated by means of complex impedance spectroscopy. Strong dependence of the electrical properties on the frequency and composition was observed. The electric polarization showed unsaturated hysteresis loops, strongly affected by leakage current.
Scheme with proposed mechanism of sorption of tetracycline on chitosan particles.
Experiments to monitor and characterize the kinetics of adsorption of tetracycline on chitosan particles are reported ...in this work. The same pseudo-order kinetics that has been widely used for describing the adsorption in systems related to wastewater purification and drug loading was used to treat the present data. As some unexpected results came out from the experiments, it was necessary a detailed deduction for this sort of kinetics to be carried out, so that approximations related to short and long times were obtained. Firstly it was shown that an apparently linear
t/
q(
t) versus
t relationship did not imply a pseudo-second-order sorption kinetics, differently of what has been repeatedly reported in the literature. It was found that this misinterpretation could be avoided by using non-linear regression. Finally, the adsorption of tetracycline on chitosan particles was analyzed, using the insights obtained from theoretical analysis, and the parameters generated were used to analyze to adsorption kinetics and to propose an adsorption mechanism.
Levothyroxine (LT4) is a form of thyroid hormone used to treat hypothyroidism. In the brain, T4 is converted to the active form T3 by type 2 deiodinase (D2). Thus, it is intriguing that carriers of ...the Thr92Ala polymorphism in the D2 gene (DIO2) exhibit clinical improvement when liothyronine (LT3) is added to LT4 therapy. Here, we report that D2 is a cargo protein in ER Golgi intermediary compartment (ERGIC) vesicles, recycling between ER and Golgi. The Thr92-to-Ala substitution (Ala92-D2) caused ER stress and activated the unfolded protein response (UPR). Ala92-D2 accumulated in the trans-Golgi and generated less T3, which was restored by eliminating ER stress with the chemical chaperone 4-phenyl butyric acid (4-PBA). An Ala92-Dio2 polymorphism-carrying mouse exhibited UPR and hypothyroidism in distinct brain areas. The mouse refrained from physical activity, slept more, and required additional time to memorize objects. Enhancing T3 signaling in the brain with LT3 improved cognition, whereas restoring proteostasis with 4-PBA eliminated the Ala92-Dio2 phenotype. In contrast, primary hypothyroidism intensified the Ala92-Dio2 phenotype, with only partial response to LT4 therapy. Disruption of cellular proteostasis and reduced Ala92-D2 activity may explain the failure of LT4 therapy in carriers of Thr92Ala-DIO2.
Background
Chronic periapical lesions (CPLs) are common lesions of the oral cavity and are the result of caries, tooth fracture, iatrogenic causes, or factors causing contamination and pulp necrosis. ...Inflammatory cells participate in the expansion of CPLs by releasing factors that stimulate or inhibit osteolytic activity. The objective of this study was to investigate the participation of RANKL, TNF‐α, cathepsin K, IL‐33, and OPG in the development of radicular cysts (RCs) and periapical granulomas (PGs).
Methods
Paraffin‐embedded sections of 30 RCs and 22 PGs were submitted to immunohistochemistry.
Results
Immunoexpression of the proteins studied was observed in the epithelium and capsule of RCs, as well as in connective tissue of PGs. The expression of the osteoclastogenic factors studied differed significantly in RCs and PGs (P < .001), with lower expression of OPG in RCs. In PGs, the lowest expression was observed for cathepsin K. Comparison of the 2 lesions showed a similar participation of RANKL and IL33, while a significant difference was observed for OPG (P < .001), TNF‐α (P = .002), and cathepsin K (P = .016). No association of the expression of the proteins with lesions size was observed.
Conclusions
This study demonstrated the participation of RANKL, TNF‐α, IL‐33, cathepsin K, and OPG in the development of RCs and PGs, with emphasis on the highest immunoreactivity of cathepsin in RCs and TNF‐α and OPG in PGs. OPG possibly determines the slower growth of PGs compared to RCs.
For applications benefitting from the swelling properties of nanolayered silicates (clay minerals), it is of paramount importance to understand the hysteresis in the clay–water interaction. In this ...context, the present work investigates how the thermal history of Na+- and Li+-intercalated fluorohectorite affects the hydration process. By combining X-ray diffraction and thermogravimetric analysis, water adsorption of preheated and non-preheated fluorohectorite was measured and analyzed in terms of the characteristic interlayer distance. The number of water molecules per cation was also inferred. We find that some of the hydration states in preheated samples are suppressed, and transitions to higher hydration states are achieved at higher relative humidity values. This could be due to the initial water content that facilities crystalline swelling. However, the data for Li-fluorohectorite do not exclude the possibility of a low temperature Hofmann–Klemen effect at 150 °C. Our study also provides strong hints that the so-called 1.5 water layer state, observed in previous studies on smectites, is a metastable state. In addition, the impact of a hydrogenous structure in the interlayer space of Li-fluorohectorite on the clay’s hydration behavior is demonstrated. The results, if generalized, would have strong implications on a wide range of applications, where the thermal history of smectites is important.
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•IPEC particles were prepared with positive and negative net charges.•Sorption of sodium chromoglycate and tetracycline hydrochloride was carried out.•Tetracyline adsorbed both on ...positive and negatively charged IPECs.•Protonation by the tetracyline resulted in disruption of IPEC structure.
Interpolyelectrolyte complexes of chitosan and poly(sodium 4-styrenesulfonate) NaPSS were synthesized and obtained in the form of solid particles, with two different sulfonate to aminium molar ratios: 0.7, resulting in particles with positive zeta potential (IPEC+), and 1.4, yielding particles with negative zeta potential (IPEC−). Both particles were characterized as potential drug sorbents using differently charged drugs: sodium cromoglycate (negatively charged), and tetracycline hydrochloride (positively charged). The adsorption isotherm for cromoglycate and tetracycline on IPEC+ was adequately described by the Langmuir model, while the IPEC− sorption of tetracycline followed the Redlich-Peterson isotherm without the occurrence of cromoglycate sorption. The sorption kinetics consisted of two processes, one fast and the other slow, which were correlated to purely surface-related interactions and processes that resulted in diffusion and/or destruction/rearrangement on the particle surface and subsurface, respectively. Charge build up equilibrium and kinetics were also monitored via zeta potential measurements, and the differences between mass drug uptake and particle charging were used to propose adsorption mechanisms for the systems studied in this work.
Visceral leishmaniosis is a neglected tropical disease. We evaluated the spatial distribution of cases of visceral leishmaniosis in the state of Alagoas, Brazil. All cases of VL, registered by the ...health department, were analyzed and georeferenced. Results: Between 2008 and 2017, 97.1% of the municipalities presented sporadic classification of transmission. With temporal evolution, the incidence of cases of visceral leishmaniosis was concentrated in most municipalities in the microregion of Santana do Ipanema-AL. Space-time analysis, if considered, may promote the improvement of surveillance and control actions of visceral leishmaniosis.
Under the auspices of the European League Against Rheumatism (EULAR), a study group of investigators representing European biologic DMARD (bDMARD) registers was convened. The purpose of this initial ...assessment was to collect and compare a cross section of patient characteristics and collate information on the availability of potential confounders within these registers.
Baseline characteristics of patients starting their first bDMARD in an arbitrary year (2008) for the treatment of RA, including demographic and disease characteristics, bDMARD drug details and co-morbidities, were collected and compared across 14 European bDMARD registers.
A total of 5320 patients were included. Half the registers had restricted recruitment to certain bDMARDs during the study year. All registers` collected data on age, gender, disease duration, seropositivity for IgM-RF and 28-joint DAS (DAS28). The mean DAS28 ranged from 4.2 to 6.6 and the mean HAQ from 0.8 to 1.9. Current smoking ranged from 9% to 34%. Nine registers reported co-morbidities with varying prevalence.
In addition to demonstrating European-wide collaboration across rheumatology bDMARD registers, this assessment identified differences in prescribing patterns, recruitment strategies and data items collected. These differences need to be considered when applying strategies for combined analysis. The lack of a common data model across Europe calls for further work to harmonize data collection across registers.
PEO-PPO-PEO triblock copolymers (usually referred as EPE) have been employed in different fields, with a remarkable emphasis in biomedical-related applications. They are amphiphilic macromolecules, ...in which PEO segments are soluble in the aqueous phase, while PPO blocks have hydrophobic character. In this work we carried out experiments with surface tensiometry of aqueous solutions of an EPE copolymer, well-known as Kolliphor P188, as a function of temperature and concentration. From the resultant data, thermodynamic relationships were related to adsorption at non-saturated liquid/air interface (low copolymer concentrations). Surface excess curves were calculated from Kohlrausch-William-Watts (KWW) functions fitted to experimental data and critical micellar concentration,
was determined. The relationship of
and temperature was similar to the observed for the adsorption of EPE copolymer at non-saturated liquid/air interface: there was a drastic change in enthalpy and entropy of adsorption/micellization at
which was correlated to the critical micellar temperature,
for this copolymer.
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