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Background-Retrospective postinfarction studies revealed that decreased heart rate turbulence (HRT) indicates increased risk for subsequent death. This is the first prospective study to validate HRT in a large cohort of the reperfusion era. Methods and Results-One thousand four hundred fifty-five survivors of an acute myocardial infarction (age Ͻ76 years) in sinus rhythm were enrolled. HRT onset (TO) and slope (TS) were calculated from Holter records. Patients were classified into the following HRT categories: category 0 if both TO and TS were normal, category 1 if either TO or TS was abnormal, or category 2 if both TO and TS were abnormal. The primary end point was all-cause mortality. During a follow-up of 22 months, 70 patients died. Multivariately, HRT category 2 was the strongest predictor of death (hazard ratio, 5.9; 95% CI, 2.9 to 12.2), followed by left ventricular ejection fraction (LVEF) Յ30% (4.5; 2.6 to 7.8), diabetes mellitus (2.5; 1.6 to 4.1), age Ն65 years (2.4; 1.5 to 3.9), and HRT category 1 (2.4; 1.2 to 4.9). LVEF Յ30% had a sensitivity of 27% at a positive predictive accuracy level of 23%. The combined criteria of LVEF Յ30%, HRT category 2 or LVEF Ͼ30%, age Ն65 years, diabetes mellitus, and HRT category 2 had a sensitivity of 24% at a positive predictive accuracy level of 37%. The combined criteria of LVEF Յ30% or LVEF Ͼ30%, age Ն65 years, diabetes mellitus, and HRT category 1 or 2 had a sensitivity of 44% at a positive predictive accuracy level of 23%. Conclusions-HRT is a strong predictor of subsequent death in postinfarction patients of the reperfusion era. (Circulation.

International audienceWe report here a simple method for controlling the crystal size and morphology of zeolitic imidazolate framework-8 (ZIF-8) nanocrystals in methanol solution. ZIF-8 crystals were prepared by mixing 2-methylimidazole (Hmim) with various zinc salts for 1 h and using a Hmim/Zn(+2) salt molar ratio of 8/1. All products prepared were assigned to a sodalite-type structure and both particle size and morphology were found to be dependent on the reactivity of the Zn(+2) salt. Small ZIF-8 crystals with diameters varying between ca. 50 and 200 nm were obtained with reactive zinc salts like Zn(acac)2, Zn(NO3)2, ZnSO4 or Zn(ClO4)2 as demonstrated by SEM, TEM and DLS analyses. The use of ZnCl2, Zn(OAc)2 or ZnI2 afforded crystals with sizes varying between ca. 350 and 650 nm. Finally, the low reactive ZnBr2 salt was found to generate microsized crystals. Taking ZIF-8 crystals prepared from Zn(NO3)2, Zn(OAc)2 and ZnBr2 as representatives and through thermogravimetric analysis and BET measurements, we also demonstrated that changes in particle size induced changes in stability and adsorption properties. The small sized ZIF-8 crystals produced from Zn(NO3)2 were found to exhibit the highest surface area (1700 m2 g−1) and the best catalytic activity in Knoevenagel and Friedländer reactions

International audienceCu2+-doped zeolitic imidazolate framework (ZIF) crystals were efficiently prepared by reaction of Cu(NO3)2, Zn(NO3)2, and 2-methylimidazole in methanol at room temperature. Scanning electron microscopy, transmission electron microscopy and X-ray diffraction showed that the Cu/ZIF-8 particles were nanosized (between ca. 120 and 170 nm) and that the body-centered cubic crystal lattice of the parent ZIF-8 framework is continuously maintained, regardless of the doping percentage. Moreover, thermogravimetric analyses and specific BET surface area measurements demonstrated that the doping does not alter the high stability of ZIF-8 crystals and that the porosity only decreases at a high doping percentage (25% in Cu2+). The Cu/ZIF-8 material showed excellent catalytic activity in the [3 + 2] cycloaddition of organic azides with alkynes and in Friedländer and Combes condensations due to the high catalyst surface area and the high dispersion of Cu/ZIF-8 particles. Notably, the Cu/ZIF-8 particles not only exhibit excellent performance but also show great stability in the reaction, allowing their reuse up to ten times in condensation reactions. Our findings explored a simple and powerful way to incorporate metal ions into the backbones of open framework materials without losing their properties

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Despite the growing interest of quantum dots (QDs) in biological applications, there are many concerns regarding the potential accumulation and toxic effects of Cd-containg QDs in animals and humans. Zinc oxide QDs are promising alternatives for diagnosis and imaging but their aqueous instability has markedly limited their use. Generations 1, 2 and 3 (noted G1, G2, and G3, respectively) of new poly(amidoamine) (PAMAM) dendrons bearing a siloxane group at the focal point were prepared from 3-aminopropyltrimethoxysilane. Using tetramethylammonium hydroxide as cross-linking agent, hydrophobic oleate-capped ZnO QDs were functionalized with G1 or G2 dendrons, as evidenced by FT-IR, UV-visible and XPS analyses, and were successfully transferred in aqueous solution. AFM and TEM images show that ZnO@G1 and ZnO@G2 QDs have a spherical shape with average crystalline sizes of 5.3 and 5.1 nm, respectively. Immediately after dispersion in water, ZnO@G1 and ZnO@G2 QDs exhibit a broad and strong visible emission peak centered at 550 nm with a quantum yield of ca. 18%. A strong increase of photoluminescence quantum yields was observed over time and values up to 59% could be reached after ca. 20 days of storage in water at room temperature. The good quantum yields and the stabilities of PAMAMdendron capped ZnO QDs ensured their potential applications in cell imaging. ZnO@G2 were successfully used for the labelling of the Gram + bacterium Staphylococcus aureus. The biocompatibility of these QDs is markedly improved compared to Cd-based ones as growth inhibition tests showed that ZnO@G2 QDs could be used with concentrations up to 1 mM without altering the cell growth of the Escherichia coli bacterium while most Cd-containing QDs exhibit cytotoxicity already at the nM level. .

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