Plasticizers and related toxic degradation products in wastewater sludges.

Plasticizers can persist during the treatment of wastewaters in sewage treatment plants (STPs) and can be discharged in effluents and/or accumulated in sewage sludges. For example, di-2-ethylhexyl phthalate (DEHP) is a common plasticizer that is now considered a priority pollutant and is known to accumulate in sludges. This may add constraints to the exploitation of the beneficial uses of sludges that contain significant quantities of plasticizers. Recently, it was demonstrated in studies with pure cultures that the biodegradation of plasticizers including DEHP and di-ethylhexyl adipate (DEHA) generates toxic metabolites including 2-ethylhexanoic acid, 2-ethylhexanol, and 2-ethylhexanal. However, the environmental impacts and fate of the degradation products arising from plasticizers are unknown. Therefore, this work investigated the concentrations of DEHP and DEHA and their metabolites in the sludges from several STPs in Quebec, Canada. DEHP and DEHA were found in concentrations ranging from 15 to 346 mg kg(-1) and 4 to 743 mg kg(-1), respectively, in primary, secondary, digested, dewatered or dried sludges. Metabolites were detected in almost all sludges, except those that had undergone a drying process at high temperature. It is concluded that sludges can represent significant sources of plasticizers and their toxic metabolites in the environment.     

In vitro testing of thiolated poly(aspartic acid) from ophthalmic formulation aspects

Ocular drug delivery formulations must meet anatomical, biopharmaceutical, patient-driven and regulatory requirements. Mucoadhesive polymers can serve as a better alternative to currently available ophthalmic formulations by providing improved bioavailability. If all requirements are addressed, a polymeric formulation resembling the tear film of the eye might be the best solution. The optimum formulation must not have high osmotic activity, should provide appropriate surface tension, pH and refractive index, must be non-toxic and should be transparent and mucoadhesive. We would like to highlight the importance of in vitro polymer testing from a pharmaceutical aspect. We, therefore, carried out physical–chemical investigations to verify the suitability of certain systems for ophthalmic formulations. In this work, in situ gelling, mucoadhesive thiolated poly(aspartic acid)s were tested from ophthalmic formulation aspects. The results of preformulation measurements indicate that these polymers can be used as potential carriers in ophthalmic drug delivery.     

When Isolated at Full Receptivity,in Vitro Fertilized Wheat (Triticum aestivum,L.) Egg Cells Reveal [Ca2+]cyt Oscillation of Intracellular Origin

During in vitro fertilization of wheat (Triticum aestivum, L.) in egg cells isolated at various developmental stages, changes in cytosolic free calcium ([Ca²⁺]_cyt) were observed. The dynamics of [Ca²⁺]_cyt elevation varied, reflecting the difference in the developmental stage of the eggs used. [Ca²⁺]_cyt oscillation was exclusively observed in fertile, mature egg cells fused with the sperm cell. To determine how [Ca²⁺]_cyt oscillation in mature egg cells is generated, egg cells were incubated in thapsigargin, which proved to be a specific inhibitor of the endoplasmic reticulum (ER) Ca²⁺-ATPase in wheat egg cells. In unfertilized egg cells, the addition of thapsigargin caused an abrupt transient increase in [Ca²⁺]_cyt in the absence of extracellular Ca²⁺, suggesting that an influx pathway for Ca²⁺ is activated by thapsigargin. The [Ca²⁺]_cyt oscillation seemed to require the filling of an intracellular calcium store for the onset of which, calcium influx through the plasma membrane appeared essential. This was demonstrated by omitting extracellular calcium from (or adding GdCl₃ to) the fusion medium, which prevented [Ca²⁺]_cyt oscillation in mature egg cells fused with the sperm. Combined, these data permit the hypothesis that the first sperm-induced transient increase in [Ca²⁺]_cyt depletes an intracellular Ca²⁺ store, triggering an increase in plasma membrane Ca²⁺ permeability, and this enhanced Ca²⁺ influx results in [Ca²⁺]_cyt oscillation.     

Simulation of special bubble detectors for PICASSO

The PICASSO project is a cold dark matter (CDM) search experiment relying on the superheated droplet technique. The detectors use superheated freon liquid droplets (active material) dispersed and trapped in a polymerised gel. This detection technique is based on the phase transition of superheated droplets at about room temperature and ambient pressure. The phase transition is induced by nuclear recoils when an atomic nucleus in the droplets interacts with incoming subatomic particles. This includes CDM particles candidate as the neutralino (a yet-to-discover particle predicted in extensions of the standard model of particle physics). Simulations performed to understand the detector response to neutrons and alpha particles are presented along with corresponding data obtained at the Montreal Laboratory.     

The effect of thiol content on the gelation and mucoadhesion of thiolated poly(aspartic acid)

A synthetic poly(amino acid), poly(aspartic acid) modified with thioethyl side groups, was studied as an in situ gelling and mucoadhesive dosage form. The chemical structure and the controllable, large thiol content of the polymer were confirmed using ¹H NMR spectroscopy and Ellman's assay. In situ gelation of aqueous polymer solutions was induced by oxidation and monitored using oscillation rheometry. The strength of mucoadhesion towards excised mucosa was characterised by tensile tests in ex vivo experiments. Release kinetics of ophthalmic antibiotic ofloxacin was studied from an in situ crosslinked hydrogel and a liquid formulation to prove the sustained release of the former. © 2017 Society of Chemical Industry     

Production and blood parameters of Holstein cows treated prepartum with sodium monensin or propylene glycol

Forty-five multiparous Holstein cows were assigned to one of 3 treatments in a randomized complete block design. The objective was to evaluate the effects of sodium monensin (M) and propylene glycol (PPG) during the prepartum period on performance and metabolic parameters during the late dry and first 9 wk postpartum for cows receiving M postpartum. Treatments were: control (C), M in a controlled-release capsule to deliver 335 +/- 33 mg/d for approximately 100 d, and 300 mL/d of PPG drenched orally. Treatments started at 35 and 21 d prior to the expected date of calving for cows receiving M and PPG, respectively. To ensure that all treatments would be restricted to the prepartum period, C and PPG cows received a M controlled-release capsule in the first 24 h after calving. Prepartum propylene glycol administration increased concentrations of glucose and insulin, and decreased beta-hydroxybutyrate and nonesterified fatty acids in plasma prepartum. Milk production was similarly affected by treatments. However, prepartum M treated cows tended to produce more 3.5% fat-corrected milk compared with control, but similar to PPG. Milk fat content and yield tended to be greater for cows that received M prepartum than for C cows, while PPG cows were similar to M and C. Prepartum administration of M decreased milk protein content, but no effect was observed on protein yield.     

Copper and iron based thin film nanocomposites prepared by radio frequency sputtering. Part I: elaboration and characterization of metal/oxide thin film nanocomposites using controlled in situ reduction process

Copper and iron based thin films were prepared on glass substrate by radio-frequency sputtering technique from a delafossite CuFeO₂ target. After deposition, the structure and microstructure of the films were examined using grazing incidence X-ray diffraction, Raman spectroscopy, electron probe micro-analysis and transmission electron microscopy coupled with EDS mapping. Target to substrate distance and sputtering gas pressure were varied to obtain films having different amount and distribution of copper nanoparticles and different composition of oxide matrix. The overall reaction process, which starts from CuFeO₂ target and ends with the formation of films having different proportion of copper, copper oxide and iron oxide, was described by a combination of balanced chemical reactions. A direct relationship between the composition of the metal/oxide nanocomposite thin film and the sputtering parameters was established. This empirical relationship can further be used to control the composition of the metal/oxide nanocomposite thin films, i.e. the in situ reduction of copper ions in the target.     

Polycyclic aromatic hydrocarbons in the air in the St. Lawrence Basin (Québec)

High-volume air samples were collected from 1993 to 1996 in rural areas of Québec to investigate on the levels and the vapor-particle partitioning of polycyclic aromatic hydrocarbons (PAHs). Ranges for the mean concentrations of total PAHs (ng m(-3)) were as follows: Villeroy, 3.31-18.92; St. Anicet, 7.57-22.84; and Mingan, 0.50-0.53. Lower molecular weight PAHs predominated at all locations. Particle-gas partition coefficients (Kp) were in good correlation with their vapor pressures (r2 = 0.79-0.97) with slopes deviating from the expected value of -1. The curve of the fractions of PAHs on particles in St Anicet in 1995 fell on that of Lake Superior. In St. Anicet, fractions of phenanthrene, fluoranthene, pyrene, and chrysene on particles were close to those calculated from the soot-air partition coefficient (KSA). At all sites the mean ratios of particulate PAH of the same molecular weight but of very different reactivities were similar during the same sampling days, suggesting that particle-bearing PAHs in Villeroy and Mingan were of the same nature as those found in St. Anicet where adsorption onto soot particles was the major mechanism. Furthermore, the enthalpies of desorption for the predominant PAHs were close at all sites.     

Micro- and macrostructural characterization of polyvinylpirrolidone rotary-spun fibers

The application of high-speed rotary spinning can offer a useful mean for either preparation of fibrous intermediate for conventional dosage forms or drug delivery systems. Polyvinylpyrrolidone (PVP) and poly(vinylpyrrolidone-vinylacetate) (PVP VA) micro- and nanofibers of different polymer concentrations and solvent ratios were prepared with a high-speed rotary spinning technique. In order to study the influence of parameters that enable successful fiber production from polymeric viscous solutions, a complex micro- and macrostructural screening method was implemented. The obtained fiber mats were subjected to detailed morphological analysis using scanning electron microscope (SEM), and rheological measurements while the microstructural changes of fiber samples, based on the free volume changes, was analyzed by positron annihilation lifetime spectroscopy (PALS) and compared with their mechanical characteristics. The plasticizing effect of water tracked by ortho-positronium lifetime changes in relation to the mechanical properties of fibers. A concentration range of polyvinylpyrrolidone solutions was defined for the preparation of fibers of optimum fiber morphology and mechanical properties. The method enabled fiber formulation of advantageous functionality-related properties for further formulation of solid dosage forms.