Determination of silicon in fats and oils by electrothermal atomic absorption spectrometry with in-furnace air oxidation

A graphite-furnace atomic absorption spectrometric emthod is reported for determination of dimethylpolysiloxane (silicone) in edible fats and oils. It incorporates an air-oxidation step in the furnace program to reduce matrix interferences. The detection limit is 0.3 mg kg^?1 in soils, and short-term precision is about 6% at silicon concentrations of 1.7–2.0 mg kg^?1. The procedure was successfully applied to a variety of commercial frying fats and oils, to quantify silicone loss during polish filtration during oil manufacture, to quantify sorption of antifoam onto fried food, and to detect fugitive sources of silicone encountered in deep-fat frying operations.     

Visual spatial memory is enhanced in female rats (but inhibited in males) by dietary soy phytoestrogens

Background  

In learning and memory tasks, requiring visual spatial memory (VSM), males exhibit superior performance to females (a difference attributed to the hormonal influence of estrogen). This study examined the influence of phytoestrogens (estrogen-like plant compounds) on VSM, utilizing radial arm-maze methods to examine varying aspects of memory. Additionally, brain phytoestrogen, calbindin (CALB), and cyclooxygenase-2 (COX-2) levels were determined.     

The application of homotopy analysis method to solve nonlinear differential equation governing Jeffery–Hamel flow

In this paper Jeffery–Hamel flow has been studied and its nonlinear ordinary differential equation has been solved through homotopy analysis method (HAM). The obtained solution in comparison with the numerical ones represents a remarkable accuracy. The results also indicate that HAM can provide us with a convenient way to control and adjust the convergence region.     

Neuromodulation by soy diets or equol: Anti-depressive &; anti-obesity-like influences,age- &; hormone-dependent effects

Background  

Soy-derived isoflavones potentially protect against obesity and depression. In five different studies we examined the influence of soy-containing diets or equol injections on depression, serotonin levels, body weight gain (BW) and white adipose tissue (WAT) deposition in female Long-Evans rats at various stages of life [rats were intact, ovariectomized or experienced natural ovarian failure (NOF)].     

Enhanced Carrier Diffusion Enables Efficient Back-Contact Perovskite Photovoltaics

Back-contact architectures offer a promising route to improve the record efficiencies of perovskite solar cells (PSCs) by eliminating parasitic light absorption. However, the performance of back-contact PSCs is limited by inadequate carrier diffusion in perovskite. Here, we report that perovskite films with a preferred out-of-plane orientation show improved carrier dynamic properties. With the addition of guanidine thiocyanate, the films exhibit carrier lifetimes and mobilities increased by 3–5 times, leading to diffusion lengths exceeding 7 μm. The enhanced carrier diffusion results from substantial suppression of nonradiative recombination and improves charge collection. Devices using such films achieve reproducible efficiencies reaching 11.2 %, among the best performances for back-contact PSCs. Our findings demonstrate the impact of carrier dynamics on back-contact PSCs and provide the basis for a new route to high-performance back-contact perovskite optoelectronic devices at low cost.     

Polydopamine as a Visible-Light Photosensitiser for Photoinitiated Polymerisation

Polydopamine (PDA) is a synthetic model for melanin and has a wide range of opto-electronic properties that underpin its utility in applied and biological settings, from broadband light absorbance to possessing stable free radical species. Here, we show that PDA free radicals are photo-responsive under visible light irradiation, enabling PDA to serve as a photo-redox catalyst. Steady-state and transient electron spin resonance spectroscopy reveals a reversible amplification in semiquinone radical population within PDA under visible light. This photo-response modifies the redox potential of PDA and supports sensitisation of exogenous species via photoinduced electron transfer (PET). We demonstrate the utility of this discovery by employing PDA nanoparticles to photosensitise a common diaryliodonium photoinitiator and initiate free-radical polymerisation (FRP) of vinylic monomers. In situ ¹H nuclear magnetic resonance spectroscopy reveals an interplay between PDA-driven photosensitising and radical quenching during FRP under blue, green, and red light. This work provides crucial insights into the photoactive free radical properties of melanin-like materials and reveals a promising new application for polydopamine as a photosensitiser.