High salinity effects on the depletion attraction in colloid-polymer mixtures.

HYPOTHESIS: Depletion attraction induced by polymers can be employed across multiple disciplines. Previous studies implied that besides screening the electrostatic repulsion between colloids, adding salt may also affect the polymers even in a nonpolar solvent. Here, we study the depletion-induced gelation of a colloid-polymer model system, focusing on the salt effects on the depletion attraction. EXPERIMENTS: Confocal microscopy was used to quantitatively characterize the colloidal gels formed by the polymethylmethacrylate (PMMA)/polystyrene (PS) model system. The attraction experienced by colloids was estimated by correlating the colloidal dynamics with the local structure. Correspondingly, static light scattering was employed to systematically investigate the polymers. The resulting radius of gyration Rg and osmotic pressure were used to evaluate the depletion attraction offered by polymers. FINDINGS: Salt was discovered to lower the strength of inter-particle attraction, which can be attributed to the salt-induced decrease in Rg. The depletion attraction grew sublinearly with c, owing to the considerable decrease in Rg in the good solvent as c increased. We demonstrated how the close form equations in the framework of renormalization group theory can be employed to predict the depletion interaction using the properly determined zero-concentration radius of gyration.

Effects of Stimulation Position and Frequency Band on Auditory Spatial Perception with Bilateral Bone Conduction.

Virtual sound localization tests were conducted to examine the effects of stimulation position (mastoid, condyle, supra-auricular, temple, and bone-anchored hearing aid implant position) and frequency band (low frequency, high frequency, and broadband) on bone-conduction (BC) horizontal localization. Non-individualized head-related transfer functions were used to reproduce virtual sound through bilateral BC transducers. Subjective experiments showed that stimulation at the mastoid gave the best performance while the temple gave the worst performance in localization. Stimulation at the mastoid and condyle did not differ significantly from that using air-conduction (AC) headphones in localization accuracy. However, binaural reproduction at all BC stimulation positions led to similar levels of front-back confusion (FBC), which were also comparable to that with AC headphones. Binaural BC reproduction with high-frequency stimulation led to significantly higher localization accuracy than with low-frequency stimulation. When transcranial attenuation (TA) was measured, the attenuation became larger at the condyle and mastoid, and increased at high frequencies. The experiments imply that larger TAs may improve localization accuracy but do not improve FBC. The present study indicates that the BC stimulation at the mastoid and condyle can effectively convey spatial information, especially with high-frequency stimulation.

Syntheses, Characterization, Crystal Structures and Antimicrobial Activity of Schiff Base Copper(II) Complexes Derived from 2-Bromo-6-((2-(isopropylamino)ethylimino)methyl)phenol.

Three new copper(II) complexes, [Cu(LH)2]Br2 (1), [Cu(LH)2]NCS2 (2), and [Cu(LH)2](NO3)2 (3), where LH is the zwitterionic form of 2-bromo-6-((2-(isopropylamino)ethylimino)methyl)phenol (HL), were synthesized and characterized by elemental analysis, IR and UV-vis spectroscopy. The structures of the complexes were further confirmed by single crystal X-ray structure determination. All compounds are mononuclear copper(II) complexes. The Cu atoms in the complexes are coordinated by two imino N and two phenolate O atoms from two LH ligands, forming square planar coordination. The compounds were assayed for their antimicrobial activities.

Enhancing the Nutritional Properties of Bread by Incorporating Mushroom Bioactive Compounds: The Manipulation of the Pre-Dictive Glycaemic Response and the Phenolic Properties.

Wheat bread supplemented with mushroom powder from three different species of mushrooms was investigated in terms of starch characteristics (content, gelatinisation, and digestibility) and antioxidant capacities. The decrease in total starch contents, and increase in phenolic contents of the breads, were associated with increased mushroom powder contents. Mushroom inclusion reduced the rate of reducing sugar released over 120 min in an in vitro digestion compared to the control sample, implying a lower area under the curve (AUC) value with the inclusion of mushroom powder and a potentially lower predicted glycaemic response of the bread. Mushroom powder incorporation also enhanced the DPPH radical scavenging assay and oxygen radical absorbance capacity (ORAC) compared to control bread. The action of the addition of different mushroom powders on the bread crust and crumb microstructure properties was also studied. Mushroom powder altered the internal microstructure of the bread crust and crumb by affecting the interactions between starch and the other components of the bread. Overall, this shows that mushroom powder could be added to bread to deliver health benefits to consumers.

Addition of mushroom powder to pasta enhances the antioxidant content and modulates the predictive glycaemic response of pasta.

This study reports the effects of addition of mushroom powder on the nutritional properties, predictive in vitro glycaemic response and antioxidant potential of durum wheat pasta. Addition of the mushroom powder enriched the pasta as a source of protein, and soluble and insoluble dietary fibre compared with durum wheat semolina. Incorporation of mushroom powder significantly decreased the extent of starch degradation and the area under the curve (AUC) of reducing sugars released during digestion, while the total phenolic content and antioxidant capacities of samples increased. A mutual inhibition system between the degree of starch gelatinisation and antioxidant capacity of the pasta samples was observed. These results suggest that mushroom powder could be incorporated into fresh semolina pasta, conferring healthier characteristics, namely lowering the potential glycaemic response and improving antioxidant capacity of the pasta.

Physical, Predictive Glycaemic Response and Antioxidative Properties of Black Ear Mushroom (Auricularia auricula) Extrudates.

Black ear mushroom (Auricularia auricula) is an important genus of cultivated mushroom, which contains health benefits. Incorporating black ear (BE) mushroom into brown rice by extrusion changed the physicochemical, and more importantly, the nutritional characteristics of the extrudates. With increased incorporation of BE mushroom in the extrudates in vitro starch digestion of the different extrudates revealed significantly reduced starch digestion, suggesting a lower glycaemic index. In addition, incorporation of BE in brown rice extrudates increased the total phenolic concentration of the samples, which led to higher % scavenging effect against free-radicals in DPPH assay. In the ORAC assay for anti-oxidant activity, BE powder exhibited the highest anti-oxidant activity, followed by 10% BE and 15% BE, and 5% BE extruded products. The extruded brown rice control exhibited the lowest antioxidant activity. Inclusion of black ear mushroom was shown to improve the nutritional qualities of the food product illustrating the connection between plant bioactive ingredients and human health.