Thermo‐Switchable Charge Transport and Electrocatalysis Using Metal‐Ion‐Modified pNIPAM‐Functionalized Electrodes

Metal ions (Ag⁺, Cu²⁺, Hg²⁺) are incorporated into an electropolymerized, poly(N‐isopropyl acrylamide), pNIPAM, thermosensitive polymer associated with an electrode using the “breathing‐in” method. The ion‐functionalized pNIPAM matrices reveal ion‐dependent gel‐to‐solid phase‐transition temperatures (28 ± 1 °C, 25 ± 1 °C, 40 ± 1 °C for the Ag⁺, Cu²⁺, and Hg²⁺‐modified pNIPAM, respectively). Furthermore, the ion‐functionalized polymers exhibit quasi‐reversible redox properties, and the ions are reduced to the respective Ag⁰, Cu⁰, and Hg⁰ nanocluster‐modified polymers. The metal‐nanocluster‐functionalized pNIPAM matrices enhance the electron transfer (they exhibit lower electron‐transfer resistances) in the compacted states. The electron‐transfer resistances of the metal‐nanocluster‐modified pNIPAM can be cycled between low and high values by temperature‐induced switching of the polymer between its contracted solid and expanded gel states, respectively. The enhanced electron‐transfer properties of the metal nanocluster‐functionalized polymer are attributed to the contacting of the metal nanoclusters in the contracted state of the polymers. This temperature‐switchable electron transfer across a Ag⁰‐modified pNIPAM was implemented to design a thermo‐switchable electrocatalytic process (the temperature‐switchable electrocatalyzed reduction of H₂O₂ by Ag⁰‐pNIPAM).     

‘Diffuse skin browning’ in 1‐MCP‐treated apples: etiology and systems of control

BACKGROUND: ‘Diffuse skin browning’ (DSB) is a physiological disorder that affects Golden Delicious apples treated with 1‐methylcyclopropene (1‐MCP). Although a very high incidence is found, very little is known about the etiology of this disorder. This study aims to provide an understanding of the causes of this disorder and prevent it. RESULTS: A very high incidence of DSB was found in 1‐MCP‐treated apples independent of the location of the orchard. Similar to superficial scald, harvest maturity determines the DSB incidence, with the more mature fruit being less sensitive. The 1‐MCP dose (156 nL L^?1 or 625 nL L^?1) and the temperature at which the 1‐MCP treatment was applied (0.5 or 20 °C) did not affect the incidence of DSB. Diphenylamine (DPA) treatment did not prevent DSB, contrary to superficial scald. Additionally, controlled atmosphere storage only partially reduced the incidence of DSB, whereas progressive cooling strategies completely inhibited DSB occurrence. A direct correlation was found between the sensitivity of the Golden Delicious clone to russeting and its sensitivity to develop DSB during storage. CONCLUSION: Our results indicated that DSB and superficial scald are two different disorders involving different oxidative processes. DSB can be prevented by progressive cooling and selection of russeting‐resistant clones. Copyright © 2010 Society of Chemical Industry     

Functional food design based on a virtual food component: wheat bran equivalents for faecal bulk

This paper reports the first use of a virtual food component (VFC), which is a value that represents the functional efficacy of a food in the format of a food component, to accurately formulate a functional food and evaluate its efficacy. The effect measured was faecal bulking and the functional food was a cereal bar. The faecal bulking efficacy of ingredients was determined as their content of the VFC, wheat bran equivalents for faecal bulk (WBE_fb), which represents faecal bulking efficacy expressed in terms of the amount of wheat bran that would produce an equivalent effect. Using a validated animal model, we measured the faecal bulking efficacy of cereal bar ingredients individually and after combining them in a cereal bar recipe, before and after the combined ingredients had been baked. The sum of the WBE_fb contents of the ingredients was 29.7 WBE_fb per bar (SEM 2.4). The WBE_fb of the recipe mixture before baking was 33.2 WBE_fb per bar (SEM 2.4) and after baking was 28.5 WBE_fb per bar (SEM 2.9). Faecal bulking efficacy was not related to dietary fibre content. We conclude that the WBE_fb content of ingredients can be used to design cereal bars of specified faecal bulking efficacy and that the functionality is resistant to baking. Copyright © 2005 Society of Chemical Industry     

双核之争，谁家得利

2007年对于处理器市场来说,是双核产品真正爆发的一年。在这一年年中的时候。Intel和AMD先后拿出了500元价位的双核处理器产品,为多核心处理器的普及打下了坚实的基础。而在进入2008年之后．Intel和AMD在主流市场争斗量为激烈的“赛扬”及“闪龙”系列相继被打上双核的烙印．2008年双核完全普及的气息已经悄然而至,一场低端双核之争也随之一触即发……     

Paramagnetic Quantum Dots as Multimodal Probes for Potential Applications in Nervous System Imaging

An axonal tracer that can be detected by both magnetic resonance imaging (MRI) and fluorescence is of great interest for studying nerve regeneration, particularly for spinal cord injury repairs. In this study, we develop a new type of multifunctional nanoparticle that combines three different functionalities of paramagnetism, fluorescence, and axonal tracing into one nanomaterial. We demonstrate that the new synthesized quantum dot nanoparticles have good biocompatibilities and can be readily taken up by cells. In addition, the quantum dots show excellent longitudinal and transverse relaxivities (i.e. r ₁ ?=?11.22?±?0.10 mM^?1 s^?1 and r ₂ ?=?24.50?±?0.51 mM^?1 s^?1) at 1.5 T, MRI contrast properties better than those of Magnevist®, a commercially available MRI contrast agent. The UV–vis absorbance spectra of all the pQDs-BDA samples indicate that these tracers are stable at different temperatures. Taken together, this new nanomaterial demonstrates good performances for both optical and MR imaging modalities, suggesting its promising potential applications in non-invasive imaging, particularly as a novel multimodal axonal tracer for nervous system imaging.     

Effects of age and ritalin dosage on the mother–child interactions of hyperactive children.

Observed interactions between mothers and 54 hyperactive children in 3 age groups (4 yrs to 5 yrs 11 mo, 6 yrs to 7 yrs 11 mo, and 8 yrs to 9 yrs 11 mo) during a drug–placebo evaluation of 2 daily dosages (0.3 and 1.0 mg/kg) of Ritalin (methylphenidate). Results indicate few age or drug effects on social interactions during free play; however, numerous age and drug effects were seen in the task period. With age, children increased their compliance and decreased their negative behavior, and their mothers decreased their levels of control and management. Both doses of methylphenidate increased child compliance equally, but only at the higher dose were significant drug effects found on mothers' behavior: Mothers decreased their control and negative behavior toward children during the high-dose condition. Drug effects on these interactions were not affected by children's ages. It is concluded that although the parent–child interactions of hyperactive children improve with age, methylphenidate produces further improvements in task-related interactions. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Increase in low molecular size uronic acid in ripening banana fruit

Uronic acid soluble in ethanol/water (4:1 v/v) increased from 9 ± 1 mg kg^?1 fresh weight in pulp of unripe banana fruit. Musa (AAA Group, Cavendish subgroup) ‘Williams’, to 53 ± 13 mg kg^?1 fresh weight in fruit ripened for 13 days. This increase began within the first 2 days of ripening. Uronic acid soluble in phenol/acetic acid/water (2:1:1 w/v/v) increased from 15 ± 5 to 86 ± 17 mg kg^?1 fresh weight during the first 8 days of ripening, accompanied by a decrease in cell wall uronic acid from 10·2 ± 0·8 to 4·4 ± 0·4 g kg^?1 fresh weight. Most or all of the uronic acid in extracts of ripe pulp cochromatographed with monogalacturonic acid. The results were consistent with hydrolysis of cell wall polyuronides by exopolygalacturonase (EC 3.2.1.67).