Rayleigh-like instability in the ion-shaping of Au-Ag alloy nanoparticles embedded within a silica matrix

We have studied how spherical 23 ± 3 nm Au(45)Ag(55) nanoparticles embedded within a silica matrix transform into prolate nanorods and nanowires by irradiating them with swift heavy ions. Samples were irradiated at room temperature and normal incidence with 74 MeV Kr and 36 MeV S ions for fluences up to 1.0 × 10(15) cm(-2). We demonstrate the existence of two regimes: (i) below a critical fluence, ～ 2.0 × 10(14) cm(-2), the transformation of the spherical nanoparticle into a nanorod is an individual process, i.e. each nanoparticle transforms into a single nanorod; (ii) for larger fluences the transformation from nanorod to nanowire becomes a collective process, i.e. the break up and dissolution of unstable nanorods contribute to the growth of long nanowires. The passage from the first to the second regime can be interpreted in terms of a Rayleigh-like instability under irradiation. The latter becomes active when the diameter of the nanowire approaches its saturation width under irradiation. Furthermore, we show that the composition of the alloy is only slightly modified during the ion-shaping process. Finally, the energy and the fluence thresholds for deformation and the deformation strain-rate are estimated.     

Live‐Cell Imaging with Water‐Soluble Aminophenoxazinone Dyes Synthesised through Laccase Biocatalysis

Aminophenoxazinone dyes with variable water solubilities were assayed for the first time in a live‐cell imaging application. Among a library of ten sulfonylated chromophores, one compound gave excellent results as an endocytic marker, showing a precise subcellular distribution. The compound was compared to four commercial vital tracers, including Lucifer Yellow. The first laccase‐mediated regioselective synthesis of a diphosphorylated 2‐aminophenoxazinone dye was also described. This compound, water‐soluble at 10^?2 M , displayed modest fluorescence properties and the ability to complex Mg²⁺ and Ca²⁺ cations, therefore giving fluorescence quenching.     

Feedback consistency effects in visual and auditory word recognition: Where do we stand after more than a decade?

The role of phonology-to-spelling consistency (i.e., feedback consistency) was investigated in 3 lexical decision experiments in both the visual and auditory modalities in French and English. No evidence for a feedback consistency effect was found in the visual modality, either in English or in French, despite the fact that consistency was manipulated for different kinds of units (onsets and rimes). In contrast, robust feedback consistency effects were obtained in the auditory lexical decision task in both English and French when exactly the same items that produced a null effect in the visual modality were used. Neural network simulations are presented to show that previous demonstrations of feedback consistency effects in the visual modality can be simulated with a model that is not sensitive to feedback consistency, suggesting that these effects might have come from various confounds. These simulations, together with the authors' results, suggest that there are no feedback consistency effects in the visual modality. In contrast, such effects are clearly present in the auditory modality. Given that orthographic information is absent from current models of spoken word recognition, the present findings present a major challenge to these models. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of glycemic index of spelt and wheat bread in human volunteers

The assessment of the glycemic index (GI) seems to be an important parameter to take into account in order to better understand the physiologic effects of foods with high carbohydrate levels. Among cereals, which are major sources of carbohydrates, spelt (Triticum spelta L.) has been considered as particularly interesting from a nutritional point of view. The aim of this study was to evaluate in vivo the GI of white spelt bread in healthy subjects. The wheat (Triticum aestivum L.) white bread was used as reference food. To avoid differences in the production of both breads, spelt and wheat breads were baked under the same controlled conditions. Results showed that the glycemic profile of spelt white bread was not different from that of wheat white bread (GI of 93 ± 9). The area under the glycemic curve significantly and negatively correlated to fasting glycemia and carbohydrate intake during evening meals preceding the test. In conclusion, the glycemic response to spelt bread was similar to that of wheat bread. However, in order to avoid more inter-individual variability, our data supports the importance to propose standardised carbohydrate content for the last meal before evaluating the GI of food.     

Effect of gate length in InAs/AlSb HEMTs biased for low power or high gain

The effect of gate-length variation on DC and RF performance of InAs/AlSb HEMTs, biased for low DC power consumption or high gain, is reported. Simultaneously fabricated devices, with gate lengths between 225 nm and 335 nm, have been compared. DC measurements revealed higher output conductance g_ds and slightly increased impact ionization with reduced gate length. When reducing the gate length from 335 nm to 225 nm, the DC power consumption was reduced by approximately 80% at an f_T of 120 GHz. Furthermore, a 225 nm gate-length HEMT biased for high gain exhibited an extrinsic f_T of 165 GHz and an extrinsic f_max of 115 GHz, at a DC power consumption of 100 mW/mm. When biased for low DC power consumption of 20 mW/mm the same HEMT exhibited an extrinsic f_T and f_max of 120 GHz and 110 GHz, respectively.     

Toward the first nonpeptidic molecular tong inhibitor of wild-type and mutated HIV-1 protease dimerization

Herein we describe the synthesis and HIV-1 protease (PR) inhibitory activity of 16 new peptidomimetic molecular tongs with a naphthalene scaffold. Their peptidic character was progressively decreased. Two of these molecules exhibited the best dimerization inhibition activity toward HIV-1 wild-type and multimutated ANAM-11 proteases obtained to date for this class of molecules (～40?nM for wild-type PR and 100?nM for ANAM-11 PR). Although the peptidic character of one molecular tong was completely suppressed, the mechanism of inhibition and inhibitory potency toward both proteases were maintained.     

Adventitial Tertiary Lymphoid Organs as Potential Source of MicroRNA Biomarkers for Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is an inflammatory disease associated with marked changes in the cellular composition of the aortic wall. This study aims to identify microRNA (miRNA) expression in aneurysmal inflammatory cells isolated by laser microdissection from human tissue samples. The distribution of inflammatory cells (neutrophils, B and T lymphocytes, mast cells) was evaluated in human AAA biopsies. We observed in half of the samples that adventitial tertiary lymphoid organs (ATLOs) with a thickness from 0.5 to 2 mm were located exclusively in the adventitia. Out of the 850 miRNA that were screened by microarray in isolated ATLOs (n = 2), 164 miRNAs were detected in ATLOs. The three miRNAs (miR-15a-3p, miR-30a-5p and miR-489-3p) with the highest expression levels were chosen and their expression quantified by RT-PCR in isolated ATLOs (n = 4), M1 (n = 2) and M2 macrophages (n = 2) and entire aneurysmal biopsies (n = 3). Except for the miR-30a-5p, a similar modulation was found in ATLOs and the two subtypes of macrophages. The modulated miRNAs were then evaluated in the plasma of AAA patients for their potential as AAA biomarkers. Our data emphasize the potential of miR-15a-3p and miR-30a-5p as biomarkers of AAA but also as triggers of ATLO evolution. Further investigations will be required to evaluate their targets in order to better understand AAA pathophysiology.     

Monitoring 2-D gel-induced modifications of proteins by MALDI-TOF mass spectrometry.

In addition to more than 200 endogenously produced post-translational modifications, a detailed analysis of 2-D gel-separated proteins must also consider other modifications that a protein can experience during various steps of its separation. This review describes the use of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry to investigate some of these modifications, which can originate during sample preparation and/or during the separation phase. The analyses described were mostly conducted at pH 9-9.5, and yielded reliable information on stable adduct formation that involved protein-bound amino acids and a number of gel components, including acrylamide derivatives, gel cross-linkers, and Immobiline chemicals. The -SH group of Cys was found to be the prime target of such adducts; however, longer reaction times revealed the involvement of the epsilon-NH2 of Lys. The same analysis revealed that the failure to achieve full reduction/alkylation prior to any electrophoretic step could result in protein-protein interaction, which could lead to a number of spurious spots in the final 2-D map. The implications of these modifications on the MS analysis in particular and on proteome research in general are discussed.     

A damage to crack transition model accounting for stress triaxiality formulated in a hybrid nonlocal implicit discontinuous Galerkin‐cohesive band model framework

Modelling the entire ductile fracture process remains a challenge. On the one hand, continuous damage models succeed in capturing the initial diffuse damage stage but are not able to represent discontinuities or cracks. On the other hand, discontinuous methods, as the cohesive zones, which model the crack propagation behaviour, are suited to represent the localised damaging process. However, they are unable to represent diffuse damage. Moreover, most of the cohesive models do not capture triaxiality effect. In this paper, the advantages of the two approaches are combined in a single damage to crack transition framework. In a small deformation setting, a nonlocal elastic damage model is associated with a cohesive model in a discontinuous Galerkin finite element framework. A cohesive band model is used to naturally introduce a triaxiality‐dependent behaviour inside the cohesive law. Practically, a numerical thickness is introduced to recover a 3D state, mandatory to incorporate the in‐plane stretch effects. This thickness is evaluated to ensure the energy consistency of the method and is not a new numerical parameter. The traction‐separation law is then built from the underlying damage model. The method is numerically shown to capture the stress triaxiality effect on the crack initiation and propagation.