Summary
NAD+ availability decreases with age and in certain disease conditions. Nicotinamide mononucleotide (NMN), a key NAD+ intermediate, has been shown to enhance NAD+ biosynthesis and ameliorate various pathologies in mouse disease models. In this study, we conducted a 12 month-long NMN administration to regular chow-fed wild-type C57BL/6N mice during their normal aging. Orally administered NMN was quickly utilized to synthesize NAD+ in tissues. Remarkably, NMN effectively mitigates age-associated physiological decline in mice. Without any obvious toxicity or deleterious effects, NMN suppressed age-associated body weight gain, enhanced energy metabolism, promoted physical activity, improved insulin sensitivity and plasma lipid profile, and ameliorated eye function and other pathophysiologies. Consistent with these phenotypes, NMN prevented age-associated gene expression changes in key metabolic organs and enhanced mitochondrial oxidative metabolism and mitonuclear protein imbalance in skeletal muscle. These effects of NMN highlight the preventive and therapeutic potential of NAD+ intermediates as effective anti-aging interventions in humans.
Summary1. Many tree species undergo large fluctuations from year to year in seed production, a phenomenon known as masting. The resource budget model, based on the assumption that abundant seeding in a masting year depends on the abundance of resources stored over several years, is a key hypothesis in explaining the mechanism of masting. But do masting species really need such long-term storage to produce a large seed crop? 2. To test this hypothesis, we studied the relationship between the carbon accumulation period for seed production, as estimated by radiocarbon ( 14 C) analyses, and the coefficient of variation of annual seed production in 10 canopy tree species in a temperate deciduous forest. These species differ widely in their reproductive intervals. 3. In all the species studied, the accumulation period was < 1.4 years before seed maturation. Moreover, without taking species or reproductive intervals into account, there was no significant correlation between the carbon accumulation period and the fluctuation of annual seed production; both remained at an even level. 4. Synthesis. Our results suggest that temperate canopy trees used photosynthates produced in the current and/or the previous year for seed production, regardless of reproductive intervals. It might therefore be necessary to reconsider the importance of stored carbohydrate resources for masting.
Molecular
hydrogen is one of the essential reactants in the chemical
industry, and its generation from renewable sources such as biomass
materials and water is of great benefit to the future society. Generally,
molecular oxygen should be pre-eliminated in the hydrogen evolution
reactions (HERs) in order to avoid the reverse hydrogen oxidation
reaction (HOR). Here, we report a highly efficient HER from a formaldehyde/water
mixture using MgO supported Ag nanoparticles (AgNPs/MgO) as the catalyst
and molecular oxygen as a promoter. The HER rate depends almost linearly
on the oxygen partial pressure, and the optimal turnover frequency
(TOF) of the silver catalyst exceeds 6,600 h–1.
Based on the experimental and theoretical results, a surface stabilized
MgO/Ag–•OOH complex is suggested to be the
main catalytically active species for the HER.
Peripheral vision: A second generation dendritic phosphane, with tetraethylene glycol (TEG) moieties at the periphery, has been designed and prepared (see structure). It is particularly effective as a ligand for the title transformation when using aryl chloride substrates. To realize high catalytic activity, the TEG groups must be connected to the phosphane framework.
A new phosphine bearing dodeca(ethylene glycol) chains has been synthesized and employed as a ligand in the palladium-catalyzed Suzuki-Miyaura coupling reaction. The system was found to be highly effective using unactivated aryl chlorides as the substrate.
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