[1,3‐Bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene]chloridogold(I)

The molecule of the title compound, [AuCl(C₂₇H₃₆N₂)], which belongs to a class of potentially catalytically active N‐heterocyclic carbene complexes, has crystallographic C₂ symmetry and approximate C_2v symmetry. The structure is isostructural with the Cu^I and Ag^I analogues. A previous report of the structure of the title compound as its toluene solvate [Fructos et al. (2005). Angew. Chem. Int. Ed. 44 , 5284–5288] has inaccurate geometry for the complex molecule as a consequence of probable incorrect refinement in the space group Cc, instead of C2/c [Marsh (2009). Acta Cryst. B 65 , 782–783]. The Au—C bond length of 1.998 (4) Å in the title compound is more consistent with the mean distance of 1.979 (14) Å found in 52 other reported [AuCl(carbene)] complexes than with the shorter distance of 1.942 (3) Å given for the refinement in the space group Cc for the toluene solvate and the value of 1.939 Å obtained from the recalculation of that structure in C2/c.     

Toward a Raman/FORS discrimination between Art Nouveau and contemporary stained glasses from CdSxSe1 − x nanoparticles signatures

CdS_xSe_{1 − x} quantum dots received considerable attention in academic studies and as cut‐off filters and indirect‐gap semiconductors. These later compounds have also been used for artistic purposes to produce colored glass since the 1920s thanks to their bright colors. Because non‐invasive conditions are now mandatory when considering objects belonging to the cultural heritage, the use of Raman and fiber optics reflectance spectroscopy has been identified as potential ones to obtain information about the nanostructure of six samples of historical glass produced between the late 1920s and modern days. The average elemental composition of the nanocrystals has been deduced processing both optical and vibrational data, and the result arising has been compared taking into account the several factors affecting the experimental results. The diffusion of zinc inside the nanocrystals has also been questioned by the shift caused on the CdS‐ and CdSe‐like phonon band wavenumber and on the absorption edge wavelength. An investigation of the size distribution and crystallinity of CdS_xSe_{1 − x} nanoparticles has been also performed considering those parameters that are mainly influenced by the disorder of the system, such as the extent of the Urbach tail and the Raman bandwidth. Thanks to the results obtained, discrimination between the more recent glass and the older Art Nouveau ones has been verified, leading to the identification of a useful analytical protocol for conservation purposes. Copyright © 2015 John Wiley & Sons, Ltd.     

Pyrolysis of the hybrid energy cane: thermal decomposition and kinetic modeling using non-isothermal thermogravimetric analysis

Journal of Thermal Analysis and Calorimetry - This work aims to investigate the thermal decomposition and reaction kinetics of the hybrid energy cane, as well as its thermochemical properties....     

Controlling the leader-laggard dynamics in delay-synchronized lasers

We study experimentally the collective dynamics of two delay-coupled semiconductor lasers. The lasers are coupled by mutual injection of their emitted light beams, at a distance for which coupling delay times are non-negligible. This system is known to exhibit lag synchronization, with one laser leading and the other one lagging the dynamics. Our setup is designed such that light travels along different paths in the two coupling directions, which allows independent control of the two coupling strengths. A comparison of unidirectional and bidirectional coupling reveals that the leader-laggard roles can be switched by acting upon the coupling architecture of the system. Additionally, numerical simulations show that a more extensive control of the network architecture can also lead to changes in the dynamics of the system. Finally, we discuss the relevance of these results for bidirectional chaotic communications.     

Strategies of karyotype differentiation in Elateridae (Coleoptera, Polyphaga)

The chromosome study of five species of the family Elateridae, belonging to the subfamilies Agrypninae and Elaterinae, and the analysis of the cytogenetic data previously recorded for this family permitted the establishment of the main strategies of karyotypic differentiation that has occurred in the elaterids. In Agrypninae, the three species studied (Conoderus fuscofasciatus, Conoderus rufidens, and Conoderus sp.) showed the male karyotype 2n=16+X0. This karyotypic uniformity detected in these Conoderus species has also been shared with other species of the same genus, differing considerably from chromosomal heterogeneity verified in the subfamily Agrypninae. The use of the C-banding technique in C. fuscofasciatus and Conoderus sp. revealed constitutive heterochromatin in the pericentromeric region of the majority of the chromosomes. In C. fuscofasciatus, additional constitutive heterochromatin were also observed in the long arm terminal region of almost all chromosomes. Among the representatives of Elaterinae, the karyotype 2n=18+Xy(p) of Pomachilius sp.2 was similar to that verified in the majority of the Coleoptera species, contrasting with the chromosomal formula 2n=18+X0 detected in Cardiorhinus rufilateris, which is most common in the species of Elaterinae. In the majority of the elaterids, the chromosomal differentiation has frequently been driven by reduction of the diploid number; but, among the four cytogenetically examined subfamilies, there are some differences in relation to the trends of karyotypic evolution.     

Pixel-by-pixel analysis of DCE MRI curve patterns and an illustration of its application to the imaging of the musculoskeletal system

Dynamic contrast enhanced (DCE) MRI is a widespread method that has found broad application in the imaging of the musculoskeletal (MSK) system. A common way of analyzing DCE MRI images is to look at the shape of the time-intensity curve (TIC) in pixels selected after drawing an ROI in a highly enhanced area. Although often applied to a number of MSK affections, shape analysis has so far not led to a unanimous correlation between these TIC patterns and pathology. We hypothesize that this might be a result of the subjective ROI approach. To overcome the shortcomings of the ROI approach (sampling error and interuser variability, among others), we created a method for a fast and simple classification of DCE MRI where time-curve enhancement shapes are classified pixel by pixel according to their shape. The result of the analysis is rendered in multislice, 2D color-coded images. With this approach, we show not only that differences on a short distance range of the TIC patterns are significant and cannot be appreciated with a conventional ROI analysis but also that the information that shape maps and conventional standard DCE MRI parameter maps convey are substantially different.     

Photodynamic Activity on Biofilm in Endotracheal Tubes of Patients Admitted to an Intensive Care Unit

Ventilator-associated pneumonia (VAP) is an infection that arises after endotracheal intubation affecting patients under intensive care. The presence of the endotracheal tube (ETT) is a risk factor since it is colonized by multispecies biofilm. Antimicrobial photodynamic therapy (aPDT) could be a strategy to decontaminate ETTs. We verify if methylene blue (MB) associated with external illumination of the ETT could be an alternative to destroy biofilm. We performed an in vitro and ex vivo study. In vitro study was performed with P. aeruginosa biofilm grew over ETT for 7 days. After treatment, the surviving cells were cultured for 3 days and the biofilm was analyzed by crystal violet absorbance. Ex vivo study employed ETT obtained from extubated patients. aPDT was performed with MB (100 µm ) and red LED (λ = 640±20 nm). We quantified the biofilm thickness and used scanning electron microscopy and fluorescence technique to verify morphological and functional changes after aPDT. Our results showed that bacteria remain susceptible to aPDT after sequential treatments. We also attested that aPDT can reduce biofilm thickness, disrupt biofilm attachment from ETT surface and kill microbial cells. These data suggest that aPDT should be investigated to decrease VAP incidence via ETT decontamination.     

A Supported Bismuth Halide Perovskite Photocatalyst for Selective Aliphatic and Aromatic C–H Bond Activation

Direct selective oxidation of hydrocarbons to oxygenates by O₂ is challenging. Catalysts are limited by the low activity and narrow application scope, and the main focus is on active C−H bonds at benzylic positions. In this work, stable, lead-free, Cs₃Bi₂Br₉ halide perovskites are integrated within the pore channels of mesoporous SBA-15 silica and demonstrate their photocatalytic potentials for C−H bond activation. The composite photocatalysts can effectively oxidize hydrocarbons (C₅ to C₁₆ including aromatic and aliphatic alkanes) with a conversion rate up to 32900 μmol g_cat⁻¹ h⁻¹ and excellent selectivity (>99 %) towards aldehydes and ketones under visible-light irradiation. Isotopic labeling, in situ spectroscopic studies, and DFT calculations reveal that well-dispersed small perovskite nanoparticles (2–5 nm) possess enhanced electron–hole separation and a close contact with hydrocarbons that facilitates C(sp³)−H bond activation by photoinduced charges.