Statin Treatment Increases Lifespan and Improves Cardiac Health in Drosophila by Decreasing Specific Protein Prenylation

Statins such as simvastatin are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors and standard therapy for the prevention and treatment of cardiovascular diseases in mammals. Here we show that simvastatin significantly increased the mean and maximum lifespan of Drosophila melanogaster (Drosophila) and enhanced cardiac function in aging flies by significantly reducing heart arrhythmias and increasing the contraction proportion of the contraction/relaxation cycle. These results appeared independent of internal changes in ubiquinone or juvenile hormone levels. Rather, they appeared to involve decreased protein prenylation. Simvastatin decreased the membrane association (prenylation) of specific small Ras GTPases in mice. Both farnesyl (L744832) and type 1 geranylgeranyl transferase (GGTI-298) inhibitors increased Drosophila lifespan. These data are the most direct evidence to date that decreased protein prenylation can increase cardiac health and lifespan in any metazoan species, and may explain the pleiotropic (non-cholesterol related) health effects of statins

Controllable Synthesis of Centimeter-Sized 2D Ruddlesden-Popper Perovskite Single Crystals through Intermediate-Phase Engineering

International audience2D Ruddlesden-Popper (RP) perovskites have demonstrated highperformance emitters, and large-sized perovskite single crystals have always been pursued for efficient optoelectronic devices. However, large-sized 2D RP perovskite single crystals with high quality are still difficult to achieve due to the weak interaction between layers and strong anisotropy. Here, we show a rational design strategy to synthesize centimeter-sized 2D BM2PbBr4 (BM = benzimidazole) perovskite single crystals by intermediate-phase engineering (IPE). 1D (DMF)2BMPbBr3 intermediate-phase single crystals were structurally decoupled and transformed to perfect 2D BM2PbBr4 seed crystals with a certain thickness, presenting a huge advantage over the extrathin crystal sheets in random stacking by natural crystallization. Furthermore, the new BM with conjugated structures we obtained as the A-site of the 2D RP perovskite enhances the exciton confinement, resulting in a surprisingly large excitonic binding energy of 368.2 meV. The emitting decay time is shortened to 0.98 ns, which is the smallest among all the perovskite materials. Tailoring of the X-site components for 2D RP BM2PbBr4 - xClx (x = 1, 2, 3, and 4) series with tunable luminescence and decay time was also synthesized by IPE. We believe IPE provides a new way for synthesizing large-sized perovskite single crystals with fine-tunable properties to satisfy the target applications

Stereo‐hindrance Engineering of a Cation toward andlt-110andgt-‐oriented 2D Perovskite with Minimized Tilting and High‐performance X‐ray Detection

International audience2D <100>-oriented Dion–Jacobson or Ruddlesden–Popper perovskites are widely recognized as promising candidates for optoelectronic applications. However, the large interlayer spacing significantly hinders the carrier transport. <110>-oriented 2D perovskites naturally exhibit reduced interlayer spacings, but the tilting of metal halide octahedra is typically serious and leads to poor charge transport. Herein, a <110>-oriented 2D perovskite EPZPbBr4 (EPZ = 1-ethylpiperazine) with minimized tilting is designed through A-site stereo-hindrance engineering. The piperazine functional group enters the space enclosed by the three [PbBr6]4− octahedra, pushing Pb─Br─Pb closer to a straight line (maximum Pb─Br─Pb angle ≈180°), suppressing the tilting as well as electron–phonon coupling. Meanwhile, the ethyl group is located between layers and contributes an extremely reduced effective interlayer distance (2.22 Å), further facilitating the carrier transport. As a result, EPZPbBr4 simultaneously demonstrates high µτ product (1.8 × 10−3 cm2 V−1) and large resistivity (2.17 × 1010 Ω cm). The assembled X-ray detector achieves low dark current of 1.02 × 10−10 A cm−2 and high sensitivity of 1240 µC Gy−1 cm−2 under the same bias voltage. The realized specific detectivity (ratio of sensitivity to noise current density, 1.23 × 108 µC Gy−1 cm−1 A−1/2) is the highest among all reported perovskite X-ray detectors

REFERENCE PROCEDURES FOR THE MEASUREMENT OF GASEOUS EMISSIONS FROM LIVESTOCK HOUSES AND STORES OF ANIMAL MANURE

In the ten years before the EMILI 2012 symposium, g aseous losses from animal farms became increasingly important in the m edia. The paradox of this tendency was the great number of publications, scientific or not, even though the emissions of most animal farms had never been measured. Therefor e, the development of reference tools to measure greenhouse gas and ammonia emissio ns was important. Such tools allow recognition and remuneration of the best pract ices and equipment. Accordingly, ADEME funded an international project associating sev eral research and development organizations involved with the animal production c hain. The project proposed an initial set of 18 procedures to measure ammonia and greenho use gas emissions from animal houses and manure stores. These were adapted to the diversity of animal farms found throughout the world. Some methods were compared duri ng a “building” and a “liquid manure” experiment. Results showed a high difference among methods (ca. 80%), much higher than the estimated uncertainty. Associat ing independent emission measurements, together with a mass balance of the sy stem, is necessary for the reliability of further results. However, previously p ublished references lack uncertainty estimates of measurements that conform to GUM 2008. I n the coming years, this is one of the major concerns for measuring emission factor s. Uncertainty estimates should depend on the measurand (temporal: hourly, per batc h, yearly; spatial: animal, house, national) and include the uncertainties associated with system representativity and temporal interpolation

Mass spectrometry for the assessment of the occurrence and biological consequences of DNA adducts

Exogenous and endogenous sources of chemical species can react, directly or after metabolic activation, with DNA to yield DNA adducts. If not repaired, DNA adducts may compromise cellular functions by blocking DNA replication and/or inducing mutations. Unambiguous identification of the structures and accurate measurements of the levels of DNA adducts in cellular and tissue DNA constitute the first and important step towards understanding the biological consequences of these adducts. The advances in mass spectrometry (MS) instrumentation in the past 2–3 decades have rendered MS an important tool for structure elucidation, quantification, and revelation of the biological consequences of DNA adducts. In this review, we summarized the development of MS techniques on these fronts for DNA adduct analysis. We placed our emphasis of discussion on sample preparation, the combination of MS with gas chromatography-or liquid chromatography (LC)-based separation techniques for the quantitative measurement of DNA adducts, and the use of LC-MS along with molecular biology tools for understanding the human health consequences of DNA adducts. The applications of mass spectrometry-based DNA adduct analysis for predicting the therapeutic outcome of anti-cancer agents, for monitoring the human exposure to endogenous and environmental genotoxic agents, and for DNA repair studies were also discussed