Phononic Crystal Made of Silicon Ridges on a Membrane for Liquid Sensing.

We propose the design of a phononic crystal to sense the acoustic properties of a liquid that is constituted by an array of silicon ridges on a membrane. In contrast to other concepts, the ridges are immersed in the liquid. The introduction of a suitable cavity in the periodic array gives rise to a confined defect mode with high localization in the cavity region and strong solid-liquid interaction, which make it sensitive to the acoustic properties of the liquid. By using a finite element method simulation, we theoretically study the transmission and cavity excitation of an incident flexural wave of the membrane. The observation of the vibrations of this mode can be achieved either outside the area of the phononic crystal or just above the cavity. We discuss the existence of the resonant modes, as well as its quality factor and sensitivity to liquid properties as a function of the geometrical parameters. The performance of the proposed sensor has then been tested to detect the variation in NaI concentration in a NaI-water mixture.

Analysis of stochastic crystallization in micron-sized droplets of undercooled liquid l-arabitol.

Kinetics of isothermal crystallization of l-arabitol were analyzed from the undercooled liquid state within micron-sized droplets from micro-Raman spectroscopy. This study reveals that crystallization slightly above Tg is controlled by stochastic heterogeneous nucleation inherent to the droplet size. Microscopic Raman investigations performed in droplets give the unique opportunity to analyze the pure metastable Form II of l-arabitol. It was found that Form II is characterized by a molecular packing more compact than that of the stable Form I, inherent to strong intermolecular hydrogen bonding. Kinetics laws obtained by analyzing several droplets at different temperatures, reveal the transient character of Form II, quasi systematically detected during the crystallization process of form I. Form II appears as the first step of crystallization prior to successive short-living metastable states which is necessary to achieve a complete crystallization in Form I. It was found that the kinetics of conversion between the metastable states (Form II) into Form I is dependent on the amount of strong hydrogen bonding distinctive of Form II.

Prevalence and correlates of non-optimal secondary medical prevention in patients with stable coronary artery disease.

BACKGROUND: In patients with coronary artery disease (CAD), non-optimal use of evidence-based medications is associated with an increased risk of adverse outcome. AIMS: To assess the prevalence and correlates of non-optimal secondary medical prevention in patients with stable CAD. METHODS: We included 4184 consecutive outpatients with stable CAD. Treatment at inclusion was classified as optimal/non-optimal regarding the four major classes of secondary prevention drugs: antithrombotics; statins; angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs); and beta-blockers. For each treatment, the prescription was considered non-optimal if the drug was missing despite a class IA indication according to international guidelines. To assess the information globally, non-optimal secondary prevention was defined as at least one major treatment missing. RESULTS: The proportions of patients with non-optimal treatment were 0.7%, 7.8%, 12.9% and 10.3% for antithrombotics, statins, ACE inhibitors/ARBs and beta-blockers, respectively. Non-optimal secondary medical prevention was observed in 16.8% of cases. By multivariable analysis, the correlates of non-optimal secondary medical prevention were long time interval since last coronary event (P<0.0001), older age (P<0.0001), diabetes mellitus (P<0.0001), hypertension (P<0.0001), no history of myocardial infarction (P=0.001), no history of coronary revascularization (P=0.013) and low glomerular filtration rate (P=0.042). CONCLUSIONS: Although most patients with stable CAD are receiving evidence-based medications according to guidelines, there remain subgroups at higher risk of non-optimal treatment. In particular, it might be feasible to improve prevention by focusing on patients in whom a long time has elapsed since the last coronary event.

Structure determination of L-arabinitol by powder X-ray diffraction.

Powder X-ray diffraction patterns of the commercial phase of L-arabinitol were recorded with a laboratory diffractometer. The starting structural model was found by a Monte-Carlo simulated annealing method. The final structure was obtained through Rietveld refinements with soft restraints on the interatomic bond lengths and bond angles. H atoms of hydroxyl groups were localized by minimization of the crystalline energy. The cell is triclinic with the space group P1 and contains two molecules. The crystalline cohesion is achieved by an important network of O-H···O hydrogen bonds.

Novel tailormade Bi4MO4(PO4)2 structural type (M = Mg, Zn).

In the Bi(2)O(3)-MO-P(2)O(5) ternary system, the commonly observed sizable 1D ribbon-like units have been extended to their 2D infinite end member, leading to the novel tailormade Bi(4)MO(4)(PO(4))(2) compounds. It contains planar [Bi(2)O(2)](2+) derivatives, separated by two slabs of PO(4), which create channels hosting the M(2+) cations (M = Mg, Zn). For both compounds, supercell orderings occur comparatively to the predicted ideal crystal structure (V(Mg) = 2V(ideal) and V(Zn) = 8V(ideal)). In the Mg case a transition into the ideal lattice occurs above 450 °C. In spite of the conceptual assembly of 2D motifs, the final architecture is three-dimensional due to strong interbonds. Thus, our work gives new insights on the possibility for versatile organization of original secondary building units (SBUs) able to self-assemble into predicted structural edifices. Single-crystal and powder XRD versus temperature, high-temperature (31)P NMR, as well as transmission electron microscopy were used for structural characterization. Preliminary electric characterization is also reported.

Solid-state vitrification of crystalline griseofulvin by mechanical milling.

The thermodynamic, dynamic, and structural changes of crystalline griseofulvin upon high-energy ball milling at room temperature have been studied. The investigations have been performed by differential scanning calorimetry (DSC), dielectric relaxation spectroscopy, and powder X-ray diffraction. The results indicate that this compound undergoes a direct crystal-to-glass transformation upon milling, whereas no glass transition can be clearly detected upon heating because of the exceptional sub-glass transition temperature (T(g) ) recrystallization of the milled sample. This intrinsic difficulty for characterizing the glassy state has been overcome using three independent strategies: (i) comparison of the evolutions upon milling of both the crystalline powder and the quenched liquid, (ii) use of fast DSC to delay the recrystallization event, and (iii) search for dielectric ß relaxations typical of glasses in the milled compound.