פרסומים

Background Repeated checking is a common ritual in obsessive-compulsive disorder (OCD). van den Hout and Kindt (2003b) devised a task demonstrating paradoxical reductions in memory confidence following repeated checking. This effect was later found to be contingent upon response inhibition. The current study aims to (1) test an alternative interpretation, whereby repeated-checking effects are caused by viewing multiple exemplars, and (2) test whether repeated checking affects response inhibition.

Docosahexaenoic acid (DHA) promotes synthesis of anti-inflammatory prostaglandins and relief of dry eye symptoms. However, topical ophthalmic application of DHA is difficult because of its lipophilic property. Therefore, it is important to develop aqueous-based formulation with enhanced capabilities. Novel, unique water-dilutable microemulsions (MEs) were constructed to allow loading of naturally occurring rigid long-chain triglyceride of DHA (TG-DHA). The TG-DHA serves as solubilizate and as the oil phase, therefore preparation is poor in oil. The structural transformations of MEs upon water dilution were studied by SAXS, viscosity, electrical conductivity, self-diffusion NMR, DSC, cryo-TEM, and DLS techniques. At low water content a new type of water-in-oil (W/O) structure is formed. The glycerol/water phase hydrates the headgroups of surfactants, and the oil solvates their tails, forming ``ill-defined bicontinuous domains\''\. Upon further water dilution more structured bicontinuous domains of high viscosity are formed. After additional dilution, the mesophases invert to oil-in-water (O/W) droplets of similar to 8 nm. In the structures composed of up to 25 wt% water, the TG-DHA spaces and de-entangles the surfactant tails. Once the bicontinuous structures are formed, the surfactants and TG-DHA content decrease and their interfacial layer shrinks, leading to entanglement and buildup of viscous non-Newtonian mesophase. Above 70 wt% water TG-DHA is embedded in the core of the O/W droplets, and its effect on the droplets' structure is minimal. This new dilutable ill-defined microemulsion can be a potential delivery vehicle for ophthalmic TG-DHA transport. (C) 2015 Elsevier Inc. All rights reserved.

In this study we characterized a new and improved transport vehicle for 2,6-diisopropylphenol (propofol), a hydrophobic anesthesia drug, in the absence and presence of dendrimers being a transporting agents across cells, polypropylenimine (PPI) dendrimer generation 2 (PPI-G2) into a microemulsion (ME). Three unique systems of water-dilutable compositions capable of inverting from W/O to bicontinuous and to O/W structures upon water dilutions were studied by means of electrical conductivity, electron paramagnetic resonance (EPR), and self-diffusion nuclear magnetic resonance (SD-NMR). The microviscosity, as well as the order parameter (from EPR results) increase with the increase in the dendrimer content, while inverting the structures from W/O to bicontinuous ME. Inversion from the bicontinuous mesophase to the O/W nanodroplets caused a very minor increase in the order parameter. Self-diffusion NMR measurements provided information on the diffusivity and the interactions of the different components of the ME. It was found that propofol has no effect on the diffusivity of the components since it is embedded within the core of the ME droplets. However, the dendrimer increases the diffusivity of water. In addition, we learned that at high dendrimer content, it remains solubilized; however its location at the ME/water interface moves to the water continuous phase. The study demonstrates the ability of water dilutable MEs to act as drug carriers hosting both propofol and dendrimer. (C) 2016 Elsevier B.V. All rights reserved.

Subclinical chronic mastitis was induced to examine the effects on oocyte developmental competence. Uninfected Holstein cows were intramammary administrated with serial (every 48 h for 20 days) low doses of toxin of Staphylococcus aureus origin (Gram-positive; G+), endotoxin of Escherichia coli origin (Gram-negative; G–) or sterile saline (control). Follicular fluid of toxin- and saline-treated cows was aspirated from preovulatory follicles and used as maturation medium. Oocytes harvested from ovaries collected at the abattoir were matured and then fertilised and cultured for 8 days. The percentage of oocytes undergoing nuclear maturation, determined by meiotic nuclear stages, did not differ between groups. Cytoplasmic maturation, determined by cortical granule distribution, was affected by both toxins (P < 0.05). The percentage of oocytes cleaving to 2- and 4-cell embryos and of embryos developing to the blastocyst stage was lower in both toxin-treated groups than in the control group (P < 0.05). There was no significant difference in the total cell number in Day 8 blastocysts among the groups; however, the apoptotic index was higher in both toxin-treated groups compared with control (P < 0.05). The relative abundance of prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclo-oxygenase; PTGS2) mRNA increased, whereas that of growth differentiation factor 9 (GDF9) decreased in matured oocytes. In addition, PTGS2 expression increased and POU class 5 homeobox 1 (POU5F1) expression decreased in 4-cell embryos developed from both G+ and G– oocytes. Thus, regardless of toxin type, subclinical mastitis disrupts oocyte cytoplasmic maturation and alters gene expression in association with reduced developmental competence.

Much remains unknown about what drives microbial community structure and diversity. Highly structured environments might offer clues. For example, it may be possible to identify metabolically similar species as groups of organisms that correlate spatially with the geochemical processes they carry out. Here, we use a 16S ribosomal RNA gene survey in a lake that has chemical gradients across its depth to identify groups of spatially correlated but phylogenetically diverse organisms. Some groups had distributions across depth that aligned with the distributions of metabolic processes predicted by a biogeochemical model, suggesting that these groups performed biogeochemical functions. A single-cell genetic assay showed, however, that the groups associated with one biogeochemical process, sulfate reduction, contained only a few organisms that have the genes required to reduce sulfate. These results raise the possibility that some of these spatially correlated groups are consortia of phylogenetically diverse and metabolically different microbes that cooperate to carry out geochemical functions.

The demand for catalyst with higher activity and higher selectivity is still a central issue in current material science community. On the basis of first-principles calculations, we demonstrate that the catalytic performance of the Pd–TiO₂ hybrid nanostructures can be selectively promoted or depressed by choosing the suitable shaped Pd and TiO₂ nanocrystals. To be more specific, the catalytic activities of Pd nanoparticles enclosed by (100) or (111) facets can be promoted more significantly when dosed on the TiO₂(001) than on TiO₂(101) under irradiation. Such theoretical prediction has then been further verified by the experimental observations in which the Pd(100)–TiO₂(001) composites exhibit the highest catalytic performance toward the activation of oxygen among all the other shaped hybrid nanostructures. As a result, the selection of facets of support materials can provide an extra tuning parameter to control the catalytic activities of metal nanoparticles. This research opened up a new direction for designing and preparing catalysts with enhanced catalytic performance.