Investigation of palladium and platinum levels in food by sector field inductively coupled plasma mass spectrometry.

Over the last two decades, there has been increased concern regarding the impact of some noble metals, such as Pd and Pt, on human health. These elements pollute the environment due to their widespread use as catalytic converters and in medical applications. The risk they pose to human health and the environment is still controversial; however, literature data point to diet as an important source of uptake by the human body. Within this context, the total Pd and Pt content of several Italian food commodities has been investigated. A total of 90 samples, including flour products, vegetables and foodstuffs of animal origin (meat, milk and eggs), were collected and freeze-dried. Samples were analyzed by sector field inductively coupled plasma mass spectrometry (SF-ICP-MS) after chopping or crushing followed by freeze-drying and microwave (MW)-assisted acid digestion in a Class-100 clean-room. A mathematical approach was adopted to correct the mass signals for still unresolved interference (mDeltam = 300, 10 000). The lowest and highest concentrations of Pt, i.e. 17 and 93 ng kg(-1) (dry weight, dw), were found in vegetables and flour products, respectively. The lowest Pd level (2830 ng kg(-1) dw) was found in eggs and the highest (47 800 ng kg(-1) dw) in vegetables.     

PIXE and XRF analysis of particulate matter samples: an inter-laboratory comparison

PIXE and XRF are very effective techniques in atmospheric aerosol investigation, therefore they are extensively used by the authors. In this work an inter-laboratory comparison of the results obtained analysing several samples (collected on different substrata) with both techniques is presented: the samples were analysed by PIXE (in Florence, at the 3 MV Tandetron accelerator of LABEC laboratory) and by XRF (in Genoa and Milan, where two Oxford XRF instruments are operational). The results of the three sets of measurements are in good agreement for all the analysed samples.The aim of this work was also to compare PIXE and XRF performance in atmospheric aerosol analysis with the routine set-up currently in use at the three laboratories, to determine the best technique to be applied depending on the substratum used for aerosol sampling and the main elements of interest for each specific research project. Results of the comparison between the minimum detection limits of both techniques will be shown for all the measured elements, for different substrata (Teflon, polycarbonate and cellulose mixed esters).     

Investigation on the effect of the presence of hyperbranched polymers on thermal and mechanical properties of an epoxy UV‐cured system

The use of hydroxyl‐functionalized hyperbranched polymers (HBPs) (Boltorn^® H20, H30 and H40) was investigated with respect to a UV‐cured epoxy system. Their presence induced an increase of the final epoxy conversion, which was interpreted on the basis of a chain‐transfer reaction. A decrease of the T_g values in the photocured films was observed when the amount of HBP additive in the photocurable formulation was increased. When the amount of HBP in the photocurable resin was increased, the density of photocured films increased, indicating a decrease on the free volume. Moreover, a clear increase in toughness was observed and attributed to the plasticization effect induced by the presence of HBP. This effect is particularly interesting for epoxy thermosets, which are characterized by good mechanical properties, although they are brittle and fragile. By increasing the toughness properties of these photocured resins it may be possible to broad their applications. Copyright © 2005 Society of Chemical Industry     

Thermal Deposition of Intact Tetrairon(III) Single‐Molecule Magnets in High‐Vacuum Conditions

A tetrairon(III) single‐molecule magnet is deposited using a thermal evaporation technique in high vacuum. The chemical integrity is demonstrated by time‐of‐flight secondary ion mass spectrometry on a film deposited on Al foil, while superconducting quantum interference device magnetometry and alternating current susceptometry of a film deposited on a kapton substrate show magnetic properties identical to the pristine powder. High‐frequency electron paramagnetic resonance spectra confirm the characteristic behavior for a system with S = 5 and a large Ising‐type magnetic anisotropy. All these results indicate that the molecules are not damaged during the deposition procedure keeping intact the single‐molecule magnet behavior.     

Carbon nanotubes supported Pt–Au catalysts for methanol-tolerant oxygen reduction reaction: A comparison between Pt/Au and PtAu nanoparticles

Two kinds of Pt–Au/CNT catalysts with different structures are prepared by synthesizing the formerly separated Pt/Au (Au separating Pt) in separate solutions, and PtAu nanoparticles in mixed solution using the borohydride reduction method with trisodium citrate as the stabilizing agent, and then depositing the metal colloid nanoparticles on the carbon nanotubes supporting material. The structural information and particle size are characterized by UV–vis absorption spectra, transmission electron microscopy (TEM), and X-ray diffraction (XRD). The results confirm the formation of Pt–Au nanoparticles with PtAu and separated Pt/Au structures. The catalytic activities for methanol oxidation reaction and oxygen reduction reaction are examined by electrochemical measurements. Compared with the Pt/CNT catalyst, the two Pt–Au/CNT catalysts show a lower overpotential for the oxygen reduction reaction in the presence of methanol, indicating a higher methanol tolerance on Au-modified Pt nanoparticles. Particularly, the Pt/Au/CNT catalyst with Au separating Pt nanoparticles structure exhibits the significantly higher methanol tolerance than PtAu/CNT catalyst. The enhanced methanol tolerance may be attributed to less methanol adsorption on Pt surface due to the effect of Au nanoparticles.     

Recollection and familiarity in amnesic mild cognitive impairment.

Objective: To investigate whether, in patients with amnesic mild cognitive impairment (a-MCI), recognition deficits are mainly due to a selective impairment of recollection rather than familiarity. Methods: Nineteen patients with a-MCI and 23 sex-, age-, and education-matched healthy controls underwent two experimental investigations, using the Process Dissociation Procedure (PDP) and the Remember/Know (R/K) procedure, to assess the differential contribution of recollection and familiarity to their recognition performance. Results: Both experimental procedures revealed a selective preservation of familiarity in a-MCI patients. Moreover, the R/K procedure showed a statistically significant impairment of recollection in a-MCI patients for words that were either read or anagrammed during the study phase. Conclusions: A-MCI is known to be commonly associated with a high risk of conversion to Alzheimer's disease (AD). Several previous studies have demonstrated a characteristic impairment of episodic memory in a-MCI, with an early dysfunction of recognition. Our findings are consistent with the knowledge of neurodegeneration occurring in AD, which is characterized, at the earliest disease stages, by a selective involvement of the entorhinal cortex. Moreover, the current study supports the dual process model of recognition, which hypothesizes recollection and familiarity to be independent processes associated with distinct anatomical substrates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Metallopolymer capacitor in "one pot" by self-directed UV-assisted process

Silver metalized methacrylate films are prepared by single-step UV curing process with good conductivity on both sides. The major component of the composite is Bisphenol A ethoxylate dimethacrylate, which can be photopolymerized by a photoreactive initiator under UV light. Under the same conditions of UV irradiation, silver ions are deposited as metal nanoparticles while the pyrrole is oxidized to polypyrrole. The migration of silver ions and pyrrole toward both surfaces during polymerization leads to the formation of a metallo-polymer capacitor. The composite films are characterized by SEM-EDX and electrical measurements for possible applications as capacitors in flexible and/or nonplanar electronics.     

China in the World: On Photography,Montages, and the Magic Lantern

Two examples of photographic montages from the first half of the twentieth century, one by the Modern Sketch Society in the magazine Shidai manhua and the other by the photographer Lang Jingshan, craft images of the modern Chinese nation. Although dramatically different, both images rely on assemblage formats and the photographic fragment in order to present a vision of a new China within a larger global context. This article proposes a nineteenth-century precursor to these photomontages in the form of an 1885 Shanghai magic lantern show as presented in the pages of the pictorial magazine Dianshizhai huabao. Originating as a lecture on world travel by the Chinese pastor and educator Yen Yung Kiung, the lecture was reconstituted into a lithographic series by the famous illustrator Wu Youru. Intended simultaneously as entertainment, as an educational and charity event, and as a series of lithographic and photographic images, the heterogeneous components of Yen and Wu’s travelogue bring together a complex but coordinated vision of the nation. Like a photomontage in its constant juxtaposition of pictorial pieces, this transmedial ‘Tour round the world’ strives to offer a particular view of China and its place in the modern world.     

Resource allocation and the attentional demands of letter encoding.

Evaluated evidence provided by W. C. Ogden et al (see record 1981-11851-001) against encoding automaticity when the 1st letter is not terminated after a brief exposure. Seven studies were conducted using 105 undergraduates. Evidence of encoding interference was found in the 1st 2 studies when the interval between the 2 letters was varied (50–2,000 msec), but this interference disappeared when there was a constant 1,000-msec interval between letters. On the basis of these findings, it was hypothesized that any momentary reduction in the resources demanded by the primary task would result in a real allocation of resources to the secondary task, which in turn would reduce the sensitivity of the secondary task to the demands of the primary one. This was tested by reducing resource allocation to the probe task at the time of encoding by reducing the expectancy (i.e., the probability) of probes in the temporal proximity of the 1st letter. This manipulation produced a large and significant increase in encoding interference. When the intensity of the tone (probe) was decreased from 70 to 60 db, the magnitude of encoding interference was further increased. Findings suggest that the magnitude of secondary task interference depends on within-trial changes in resource allocation between primary and secondary tasks. This possibility has general implications for dual-task methodology and the measurement of attentional demands. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impact of Soluble HLA-G Levels and Endometrial NK Cells in Uterine Flushing Samples from Primary and Secondary Unexplained Infertile Women

The aim of this research was to determine the levels of human leukocyte antigen G (HLA-G) and endometrial Natural Killer ((e)NK) cell percentages in uterine flushing samples from primary and secondary infertile women. sHLA-G levels were lower in the uterine flushing samples from primary infertile women in comparison with women with secondary infertility. Lower CD56⁺KIR2DL4⁺ (e)NK cell percentages were detected in primary infertile women compared with secondary infertile women. This is the first study demonstrating that primary and secondary unexplained infertilities are characterized by different basal sHLA-G levels and CD56⁺KIR2DL4⁺ (e)NK cell percentages.