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During cryopreservation, sperm was submitted to an increase in reactive oxygen species generation. This work aimed to improve the quality of frozen equine sperm after the addition of ...antioxidants lactoferrin (Lf) and catalase (Cat) to a freezing extender. Semen from six stallions was frozen with the extenders: F1) control, INRA 82 freezing extender, F2) F1 + 500 μg/ml Lf and F3) F1 + 200 IU/ml Cat. After thawing, sperm motility parameters, membrane functionality and integrity, and acrosome integrity and spontaneous acrosome‐reacted sperm were evaluated with a computer‐assisted sperm analysis, a hypoosmotic swelling test and epifluorescent microscopy, respectively. Nitrite, hydroperoxide and iron concentrations of frozen semen were measured with spectrophotometry. The percentage of functional membrane sperm treated with Lf was higher (50.7% ± 11.6%) compared to that of the control (37.6% ± 15.6%), while the iron (61.4 ± 11.6 vs 73.3 ± 13.8 mg/dl) and nitrite concentrations (16.3 ± 7.1 vs 25.9 ± 4.2 μM/μg protein) were lower, respectively (p < .05). Thus, it can be suggested that Lf protect stallion spermatozoon during freezing as it has increased the percentage of sperm with functional membrane and decreased the lipid oxidant agents.
The presence of pharmaceutic compounds has been widely detected in water and wastewater due to the increase in their production and consumption. Since conventional treatments are not able to totally ...remove these microcontaminants, more efficient technologies, such as adsorption, must be investigated. This study aimed to evaluate the adsorption of diclofenac sodium (DS) onto commercial organoclay (Spectrogel® Type C) in static system. Process optimization was performed through Central Composite Design (CCD) and the adsorbent mass of 0.5 g and agitation speed of 200 rpm were selected as the optimum conditions. The variable initial concentration of DS was not statistically significant. Pseudo-first order model showed the best correlation to kinetic experimental data and the investigation of adsorption mechanism revealed that external mass transference was the main rate-controlling step. Equilibrium data obtained at 15 °C and at 30 °C were best described by Freundlich isotherm model and at 50 °C by Temkin isotherm model. The maximum adsorption capacity from Langmuir was of 0.133 mmol/L at 50 °C. Thermodynamically, the process is spontaneous and endothermic. Characterization analysis depicted that DS adsorption takes place on the surface of Spectrogel, which is not significantly modified by the process.
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•Adsorption of diclofenac sodium onto Spectrogel Type C organoclay was examined.•The variables agitation speed and adsorbent mass are statistically significant.•The external film diffusion is the main rate-controlling mechanism.•The process is spontaneous, endothermic and occurs on the organoclay's surface.•No significant modifications on the organoclay are verified after adsorption.
Although there are many studies about superhydrophobicity on aluminum alloys substrates and their resistance to corrosion, few studies have evaluated the effect of the initial surface condition on ...obtaining super-hydrophobic surfaces. Different initial surface treatment (sanded, blasted and untreated) conditions were investigated on 5052 aluminum alloy to evaluate their influence on obtaining superhydrophobic surfaces with anticorrosive properties in saline medium. These surfaces were obtained in three sequential steps: acid etching in hydrochloric acid solution; chemical treatment in zinc nitrate in alkaline medium; and finally, reducing surface energy by using stearic acid. The characteristics of the surface were studied using scanning electron microscopy, energy dispersive spectroscopy, confocal microscopy and contact angle measurements. The corrosion resistance was evaluated by linear potentiodynamic polarization. The results revealed that the initial surface condition influenced the superhydrophobic and anticorrosion properties of the coatings. The sample initially sanded presented the best results of contact angle, sliding angle and efficiency of corrosion resistance, with values of 154°, 5.67° and 89.82%, respectively. However, after immersion corrosion test for 28 days, the coating lost superhydrophobic character and presented hydrophilic behavior.
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•The coatings wettability was influenced by the initial treatment of the surface.•The wettability decreased after chemical modification for all conditions.•The best contact angle was 154° for the sanded initially surface.•The sanded samples had an efficiency of corrosion resistance of 89.82%.•The coating presented hydrophilic behavior after 28 days immersion in NaCl solution.
A quantificação de células progenitoras hematopoéticas pelo fenótipo (CD34+/CD45+) ou por cultivo celular (Ensaio Clonogênico – que mede as Unidades de Formação de Colônias - UFC) é usada para ...determinar a qualidade de produtos de leucaférese aplicados ao transplante de medula óssea. A razão entre os progenitores CD34+ e unidades formadoras de colônia de granulócitos e macrófagos – UFC-GM apresentam grandes variações, mas pode expressar os prejuízos decorrentes da criopreservação destas células. Nosso objetivo foi avaliar a perda de qualidade destes produtos pós criopreservação tendo como referências a relação entre CD34 e UFC pré criopreservação.
Esta análise compreendeu 177 amostras pré-criopreservação e 169 amostras pós-criopreservação. 36 amostras pós-criopreservação foram submetidas a novo cultivo para confirmação de redução da perda de capacidade proliferativa. Para avaliar a quantidade de progenitores por citometria de fluxo, as amostras foram incubadas com anticorpos anti-CD45 e anti-CD34 e analisadas conforme método indicado pela ISHAGE/ISCT. O ensaio clonogênico foi realizado pela cultura de células nucleadas do produto de leucaférese, em meio de cultura semissólido contendo ágar, soro fetal bovino e meio condicionado de linhagem 5637, como fonte de fatores de crescimento. As placas foram incubadas por 12-14 dias. Após o término da incubação, as amostras foram fixadas com vapor de formol até a data de contagem das colônias. A relação entre células CD34+ e UFC foi determinada pelo quociente entre o número de células CD34+ e o número de UFC no produto da aférese. O método de criopreservação foi automatizado e os produtos foram mantidos em nitrogênio líquido. A análise estatística dos valores foi feita pelo teste de Mann-Whitney e t-paired.
A mediana da relação CD34/UFC em amostras pré criopreservação foi de 36 (3-2143) e em amostras pós criopreservação foi de 102 (2-19171). A perda de capacidade proliferativa pós-criopreservação foi significativa p < 0,0001 (Main-Whitney U). Amostras que pós criopreservação apresentavam perdas fora dos níveis de tolerância foram repetidas e apresentaram resultados semelhantes (R CD34/CFU com mediana 425 e pós repetição 473).
A perda de capacidade proliferativa pós congelamento é muito variável entre pacientes, é necessário identificar os fatores de risco associados para prever coleta satisfatória aos pacientes com maior risco de perda da qualidade do enxerto pós criopreservação, um estudo de características clínicas dos pacientes ou de propriedades citológicas nestes produtos poderá auxiliar na interpretação destes resultados.
O ensaio clonogênico em produtos criopreservados revela a perda de capacidade proliferativa de progenitores pós-descongelamento e pode agregar valores de qualidade juntamente com a viabilidade celular. Observamos que uma taxa de cerca de 25% de amostras apresentam perda significativa da capacidade hematopoética in vitro. Os resultados foram confirmados por repetição do ensaio clonogênico, que apresentou reprodutibilidade.
•DLS and SAXS can be used to characterize sphere/worm-like transitions in microemulsions.•Increase in characteristic relaxation rate from DLS indicates this transition.•Broadening of relaxation rate ...distribution from DLS is caused by an increase in micellar dimensions.•SAXS indicates that oil phase inhibits the formation of worm-like structures.
Dynamic light scattering and SAXS were used to characterize the change in dimensions of the dispersed phase in microemulsions based on C12E9 non-ionic surfactant, butanol, xylene, and water, as a function of dispersed phase concentration. A KWW-based equation was fitted to data from intensity correlation functions of the microemulsions and a transition from spherical to worm-like geometry was related to a decrease in the dimensions of the randomly oscillating regions of the resultant systems as well as to the broadening of their characteristic relaxation rate distributions. More specifically, the transition was characterized by an increase in the characteristic relaxation rate as well as by a decrease in the stretching coefficient (related to an increased heterogeneity of more complex colloidal structures). Static SAXS was used to characterize the transition as occurring at the maximum ratio between the radii of gyration of the system with and without xylene, which was shown to me correlated to previously obtained data associating this transition to a maximum in the ratio of viscosities for the same systems.
A drastic change in apparent flow activation enthalpy (the slope of lnη0versus 1/T curve) indicates a transition between nanodrop/worm-like geometries. Display omitted
► Viscosity of a microemulsion ...has an Arrhenius-type dependence on temperature. ► Arrhenius dependence has two activation enthalpies, above and below a critical temperature. ► DLS suggests relaxation is governed by 2 relaxation rate distributions (2 KWW functions). ► Parameters from KWW equation have abrupt changes above and below same critical temperature. ► Changes related to increase/decrease of worm-like structures as a function of temperature.
Polyethoxylated alkyl compounds consist in a surfactant class that, apart from having a broad application in many fields, yields self-assembled clusters with peculiar geometries: the worm-like micelles. In this work a microemulsion consisting of xylene, water, butanol, and nonaethyleneglycol-monododecylether was studied using rheometry and dynamic light scattering. Zero-shear rate viscosity-temperature dependence had a peculiar Arrhenius character, with the occurrence of two apparent flow activation enthalpies, a higher one below 25°C, and a lower one above this very temperature. KWW equation was fitted to intensity correlation function data obtained from dynamic light scattering experiments at different temperatures. The temperature dependence of KWW-related parameters indicated that the change in flow activation enthalpy could be related to a change in micelle morphology.
Scheme showing micelle formation as both oil and surfactant concentrations are raised: (a) at very dilute concentrations, surfactant is almost entirely in the bulk and oil at the surface; (b) ...hemimicelle formation; (c) system above CMC.
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▶ Wormlike micelle-nanodrop change was characterized by maximum effective diameter. ▶ This maximum coincided with the maximum relative viscosity obtained by viscometry. ▶ Turbulent behavior occurrence was used to rheologically characterize microemulsions. ▶ Adsorption isotherms suggested BuOH in nonionic systems behave as part of oil phase.
Alkyl polyethoxylates are surfactants widely used in vastly different fields, from oil exploitation to pharmaceutical applications. One of the most interesting characteristics of these surfactants is their ability to form micellar systems with specific geometry, the so-called wormlike micelle. In this study, dynamic light scattering (DLS), capillary viscometry, torque rheometry and surface tensiometry experiments were carried out in systems based on xylene, water, butanol (cosurfactant), and nona-ethyleneglycol-monododecyl ether (surfactant), with fixed surfactant:cosurfactant:oil composition (with and without oil phase) and varying overall concentration. The results showed that a transition from wormlike micelles to nanodrops was characterized by maximum relative viscosity (depending on how relative viscosity was defined), which was connected to maximum effective diameter, determined by DLS. Surface tension suggested that adsorption at the air–water interface had a Langmuir character and that the limiting value of the surfactant surface excess was independent of the presence of cosurfactant and xylene.
Latexes based on ethyl methacrylate (EMA), acrylic acid (AA), crosslinked with 1,6-hexanediol propoxylate diacrylate (HPDA), were synthesized via emulsion polymerization, yielding dispersions with ...different acidic group contents and crosslinking densities. The latexes were thickened using various NaOH/AA molar ratios and the resultant dispersions were characterized by pH-metry, zeta potentiometry, and turbidimetry. The process of thickening by carboxyl neutralization was shown to be dependent on the neutralization effect on particle-particle interactions and particle solubilization. Turbidimetry, pH-metry, and zeta potential measurements showed that neutralization resulted in partial latex solubilization and viscometry indicated that, for a given latex, an optimum thickening was achieved for and specific NaOH/AA molar ratio, showing the existence of a relationship between thickening, particle-particle interactions, latex solubilization, and polyelectrolyte effect.
To investigate the effect of different light-curing units and depths on the degree of conversion (DC) through Fourier transform infrared spectroscopy (FTIR) and Knoop Hardness Number (KHN) of a ...silorane-based composite resin (Filtek LS, 3M ESPE, St Paul, MN, USA) (LS).
LS specimens mounted in a particular designed matrix were photoactivated by three light-cure units (LCUs) at depths of 2, 3, 4, and 5 mm. The DC was determined in a FTIR spectrometer with an attenuated total reflectance accessory. The KHN was measured in an automatic microhardness tester. The results were analyzed using the Friedman and Spearman statistical tests (α=0.05).
There was no effect of LCUs on the DC (p=0.472) or KHN (p=0.174) for all of the studied depths. The highest DC and KHN means were found at 2-mm depth, which were not statistically different from 3-mm depth, but were higher than 4-mm and 5-mm depths (p=0.007). Spearman analysis found a positive linear correlation between the variables KHN and DC (r=0.858, p<0.000).
The LCUs' effect was not verified. Values of DC and KHN for LS decreased with increasing depth. The highest values for both DC and KHN were obtained at depths of 2-3 mm.
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