Toward Detection of the Molecular Parity Violation in Chiral Ru(acac)3 and Os(acac)3.

We present a theory-experiment investigation of the helically chiral compounds Ru(acac)3 and Os(acac)3 as candidates for next-generation experiments for detection of molecular parity violation (PV) in vibrational spectra. We used relativistic density functional theory calculations to identify optimal vibrational modes with expected PV effects exceeding by up to 2 orders of magnitude the projected instrumental sensitivity of the ultrahigh resolution experiment under construction at the Laboratoire de Physique des Lasers in Paris. Preliminary measurements of the vibrational spectrum of Ru(acac)3 carried out as the first steps toward the planned experiment are presented.

The association between removing and reintroducing man-made jumps in terrain parks and severe alpine skiing and snowboarding injuries.

OBJECTIVES: To explore the effect of removing and reintroducing man-made jumps in terrain parks (TPs), on the proportion of severe injuries among alpine skiers and snowboarders in Québec, Canada. DESIGN: Quasi-experimental study. METHODS: Injuries were identified via injury report forms completed by ski patrollers during seasons 2000-2001 to 2016-2017 in Québec ski areas. Severe injuries were defined based on the type of injury or ambulance evacuation. Logistic regression analysis was used to provide adjusted odds ratios (AOR) for the comparison of the time periods before jump removal (PRE) and after jump reintroduction (POST) with the jump removal interval (INT). RESULTS: Compared with INT, the proportion of severe injuries in PRE was not significantly different (AOR: 1.05; 95% CI: 0.85-1.30), but was higher in POST (AOR: 1.76; 95% CI: 1.24-2.51) for ski areas with jump removal. In ski areas without jump removal, there was no change in PRE (AOR: 0.96; 95% CI: 0.87-1.07) and increased odds of severe injuries in POST (AOR: 1.20; 95% CI: 1.07-1.35). A supplementary analysis suggested that removing jumps from TPs has contributed significantly to a reduction in the proportion of severe injuries. This protective effect appears to decline over time. CONCLUSIONS: These results do not suggest that removing jumps from TPs as an effective long-term injury prevention strategy in skiing and snowboarding. Collecting data on exposure could improve our understanding of how removing, introducing or reintroducing man-made jumps in TPs is associated with the risk of minor and severe injuries in TPs and on regular trails.

Versatile and robust synthesis process for the fine control of the chemical composition and core-crystallinity of spherical core-shell Au@Ag nanoparticles.

Au nanoparticles (NPs) characterized by distinct surface chemistry (including dodecanethiol or oleylamine as capping agent), different sizes (∼5 and ∼10 nm) and crystallinities (polycrystalline or single crystalline), were chosen as seeds to demonstrate the versatility and robustness of our two-step core-shell Au@Ag NP synthesis process. The central component of this strategy is to solubilize the shell precursor (AgNO3) in oleylamine and to induce the growth of the shell on selected seeds under heating. The shell thickness is thus controlled by the temperature, the annealing time, the (shell precursor)/(seed) concentration ratio, seed size and crystallinity. The shell thickness is thus shown to increase with the reactant concentration and to grow faster on polycrystalline seeds. The crystalline structure and chemical composition were characterized by HRTEM, STEM-HAADF, EELS and Raman spectroscopy. The plasmonic response of Au@Ag core-shell NPs as a function of core size and shell thickness was assessed by spectrophotometry and simulated by calculations based on the discrete dipole approximation (DDA) method. Finally, the nearly monodisperse core-shell Au@Ag NPs were shown to form micrometer-scale facetted 3D fcc-ordered superlattices (SLs) after solvent evaporation and deposition on a solid substrate. These SLs are promising candidates for applications as a tunable surface-enhanced Raman scattering platform.

Terrain park feature compliance with Québec ski area safety recommendations.

OBJECTIVES: The primary objective of this paper is to examine terrain park (TP) feature compliance with recommendations from a ski area industry guide (are TP features compliant with the guide?) and determine factors that could be associated with TP feature compliance in Québec ski areas (do factors influence TP feature compliance?), Canada. These recommendations on the design, construction and maintenance are provided by the Québec Ski Areas Association Guide. METHODS: A group of two to four trained research assistants visited seven ski areas. They used an evaluation tool to assess the compliance of 59 TP features. The evaluation tool, originally developed to assess the quality of TP features based on the guide, was validated in a previous study. Compliance was calculated by the percentage of compliant measures within a given feature. The potential influence of four factors on compliance (size of the TP, size of the feature, snow conditions and type of feature) were examined using a mixed-effects logistic regression model. RESULTS: The average TP feature compliance percentage was 93% (95% CI 88% to 99%) for boxes, 91% (95% CI 89% to 94%) for rails and 89% (95% CI 86% to 92%) for jumps. The logistic regression showed that none of the four factors examined were associated with TP feature compliance with the guide. CONCLUSION: Our results suggest that TP features are highly compliant with the guide in Québec ski areas.

Copper nanoparticles of well-controlled size and shape: a new advance in synthesis and self-organization.

Here, we report a new synthetic route for spherical small copper nanoparticles (CuNPs) with size ranging from 3.5 nm to 11 nm and with an unprecedented associated monodispersity (<10%). This synthesis is based on the reduction of an organometallic precursor (CuCl(PPh3)3) by tert-butylamine borane in the presence of dodecylamine (DDA) at a moderate temperature (50 to 100 °C). Because of their narrow size distribution, the CuNPs form long-range 2D organizations (several µm(2)). The wide range of CuNPs sizes is obtained by controlling the reaction temperature and DDA-to-copper phosphine salt ratio during the synthesis process. The addition of oleic acid (OA) after the synthesis stabilizes the CuNPs (no coalescence) for several weeks under a nitrogen atmosphere. The nature and the reactivity of the ligands were studied by IR and UV-visible spectroscopy. We thus show that just after synthesis the nanoparticles are coated by phosphine and DDA. After adding OA, a clear exchange between phosphine and OA is evidenced. This exchange is possible thanks to an acid-base reaction between the free alkylamine in excess in the solution and OA. OA is then adsorbed on the NPs surface in the form of carboxylate. Furthermore, the use of oleylamine (OYA) instead of DDA as the capping agent allows one to obtain other NP shapes (nanorods, triangles and nanodisks). We get evidence that OYA allows the selective adsorption of chloride ions derived from the copper precursor on the different crystallographic faces during the growth of CuNPs that induces the formation of anisotropic shapes such nanorods or triangles.

Feasibility of using a sheathless guiding catheter for left ventricular endomyocardial biopsy performed by transradial approach.

The role of endomyocardial biopsy (EMB) in the diagnosis and treatment of adults presenting a newly unexplained cardiomyopathy remains controversial and the clinical indication varies among different centers. Furthermore, the choice of the ventricular site for EMB is still under debate. The right ventricular EMB is commonly used due to safety features and left ventricle (LV) EMB has not yet gained acceptance because of concerns about possible complications. Of note, when LV-EMB is performed, the femoral artery is usually the access site. There is a large body of evidence supporting the safety and feasibility of transradial approach in a broad spectrum of patients and settings in the catheterization laboratory. Therefore, the aim of the present manuscript is to report the feasibility of performing a LV-EMB by the transradial approach using a sheathless guiding catheter as an ad hoc procedure.

Acute myocarditis triggering coronary spasm and mimicking acute myocardial infarction.

A 24-year-old healthy man consulted to our center because of typical on-and-off chest-pain and an electrocardiogram showing ST-segment elevation in inferior leads. An urgent coronary angiography showed angiographically normal coronary arteries. Cardiovascular magnetic resonance imaging confirmed acute myocarditis. Although acute myocarditis triggering coronary spasm is an uncommon association, it is important to recognize it, particularly for the management for those patients presenting with ST-segment elevation and suspect myocardial infarction and angiographically normal coronary arteries. The present report highlights the role of cardiovascular magnetic resonance imaging to identify acute myocarditis as the underlying cause.

Stability of self-ordered thiol-coated silver nanoparticles: oxidative environment effects.

Here, we study the stability of the 2D organization of thiol-coated silver nanoparticles (NPs) by transmission electron microscopy. Whatever the alkyl chain length and the nature of the silver precursor, we show the rapid corrosion (over a few days) of the NPs by O2 from laboratory air whereas they remain stable for several weeks under a nitrogen atmosphere. We show that this phenomenon is amplified by the humidity in the air and by thiols trapped in the NP monolayers. We obtain evidence of these thiols in excess by infrared and energy-dispersive spectroscopies. This study of stability has been extended to gold nanoparticles (AuNPs) coated with dodecanethiols. The AuNPs remain stable under laboratory air because of the higher redox potential of Au compared to that of Ag and O2.

Vibrational spectra and structures of Ti-N2O and OTi-N2: a combined IR matrix isolation and theoretical study.

The reaction of atomic titanium with nitrous oxide has been reinvestigated using matrix isolation in solid neon coupled to infrared spectroscopy and by quantum chemical methods. Our technique of sublimation of Ti atoms from a filament heated at about 1500 °C allowed the formation of three species: one Ti-N(2)O pair of van der Waals (vdW) type characterized by small red shift with respect to N(2)O monomer, and two isomers of OTi-N(2) pair where N(2) is in interaction with the OTi moiety either with end-on or side-on structure. Interconversion between these structures has been performed with several wavelengths. In the visible and near-ultraviolet the conversion vdW → OTi-N(2) (end-on) is observed with characteristic times strongly varying according to the wavelength. In the near-infrared the conversion OTi-N(2) (end-on) → OTi-N(2) (side-on) occurs, the vdW species remaining unchanged. These selectivities allow 8, 6, and 4 vibrational transitions to be assigned for vdW, (3)[OTi(η(1)-NN)] (end-on), and (1)[OTi(η(2)-NN)] (side-on), respectively. Electronic and geometrical structures are also investigated with double-hybrid functionals. It has been shown that the side-on geometry corresponds to the ground state of (1)[OTi(η(2)-NN)] in the singlet electronic state. The theoretical vibrational analysis supports well the experimental attributions.

Evaluation of CO coordination energies from spectroscopic data: on the use of vibrational isotopic effects.

For molecules containing a linearly coordinated carbonyl group, relationships linking 13C and 18O isotopic effects on the CO stretching vibration to the force constant of the M-C coordination bond are proposed. These relationships are rationalized by simple considerations involving the mechanical coupling of the CO and M-C oscillators, tested on model triatomic molecules, and generalized to larger systems. Previous theoretical considerations and several examples presented here show that the long-accepted relation between the shift in the stretching frequency of the coordinated CO with respect to that of isolated CO and the coordination strength has no general predictive power. In contrast, the force constant of the coordination bond can be correlated with the coordination binding energy, and a method for empirically estimating this important parameter from spectroscopic observations of the strongly absorbing CO stretching vibrations of molecular systems or adsorbates is proposed.

Efficacy and safety of rosuvastatin and atorvastatin in patients with hypercholesterolemia and a high risk of coronary heart disease: a randomized, controlled trial.

BACKGROUND: This double-blind, multicenter, randomized trial compared rosuvastatin and atorvastatin for reducing low-density lipoprotein cholesterol (LDL-C) in adults with hypercholesterolemia and a high risk of coronary heart disease. METHODS: After a 6-week dietary lead-in period, patients with LDL-C levels > or =160 and <250 mg/dL and triglyceride levels < or =400 mg/dL were randomly assigned to 24 weeks' treatment in 1 of 3 groups, each with forced dose titrations at 12 and 18 weeks. Starting and titrated doses for each group were rosuvastatin 5, 20, and 80 mg (n = 127); rosuvastatin 10, 40, and 80 mg (n = 128); and atorvastatin 10, 40, and 80 mg (n = 128). RESULTS: At 24 weeks, LDL-C was reduced significantly more with 80 mg rosuvastatin (combined rosuvastatin group) than with atorvastatin 80 mg (60% vs 52% [P <.001]). At 12 weeks, rosuvastatin 5 and 10 mg reduced LDL-C significantly more than atorvastatin 10 mg (40% [P <.01], 47% [P <.001] vs 35%). At 18 weeks, LDL-C reductions were also significantly greater in both rosuvastatin groups than in the atorvastatin group (52% [P <.01], 59% [P <.001] vs 47%). Consequently, more patients receiving rosuvastatin achieved LDL-C goals. Total cholesterol, high-density lipoprotein cholesterol (HDL-C), non-HDL-C, apolipoproteins B and A-I, and all lipid ratios were more favorably modified by rosuvastatin at 24 weeks (P <.01). Effects of the 2 agents on triglycerides were similar. CONCLUSIONS: Rosuvastatin was more efficacious than atorvastatin in modifying lipids in patients with hypercholesterolemia and a high coronary heart disease risk.