Abstract Reactive oxygen species (ROS) are important factors mediating aging according to the free radical theory of aging. Few studies have systematically measured ROS levels in relationship to aging, partly due to the lack of tools for detection of specific ROS in live animals. By using the H2O2-specific fluorescence probe Peroxy Orange 1, we assayed the H2O2 levels of live Caenorhabditis elegans with 41 aging-related genes being individually knocked down by RNAi. Knockdown of 14 genes extends the lifespan but increases H2O2 level or shortens the lifespan but decreases H2O2 level, contradicting the free radical theory of aging. Strikingly, a significant inverse correlation between lifespan and the normalized standard deviation of H2O2 levels was observed (p < 0.0001). Such inverse correlation was also observed in worms cultured under heat shock conditions. An oxidative fluctuation hypothesis of aging is thus proposed and suggests that the ability of animals to homeostatically maintain the ROS levels within a narrow range is more important for lifespan extension than just minimizing the ROS levels though the latter still being crucial.

SALL4 has recently been identified to promote chemo-resistance in multiple types of cancer, but the underlying mechanism remains to be fully established. Open chromatin structure is important for DNA damage response (DDR) and DNA repair. Here, we demonstrate that SALL4 promotes open chromatin by destabilizing heterochromatin protein 1α (HP1α) by recruiting ubiquitin E3 ligase CUL4B to HP1α. The silencing of SALL4 in cancer cells decreased the expression levels of Glut1 and inhibited glycolysis in cancer cells. The upregulation of HP1α in human cancer cells suppressed open chromatin, glycolysis and Glut1 expression levels. Therefore, SALL4 promotes the expression of Glut1 and open chromatin through a HP1α-dependent mechanism. Impaired DDR in SALL4-deficient human cancer cells can be rescued by the restored expression of Glut1, indicating the importance of HP1α-Glut1 axis in SALL4-mediated DDR. These findings demonstrate that SALL4 could induce drug resistance by enhancing DDR and DNA repair through promoting glycolysis and subsequent chromatin remodeling.

Virtual desktop infrastructure (VDI) deployments are a rapidly growing segment in the Mobile/Cloud Era. Compared to traditional enterprise desktop deployments, VDI can reduce the total cost of ownership by as much as 50%. However, the cost of powering a VDI deployment is still a significant IT expense. Typically these deployments consist of a complex system of interconnected server, storage and networking components. Thus, it is challenging to minimize energy consumption of the entire system while at the same time satisfying performance requirements. In this work, we first derive an accurate VDI performance model and then propose a hierarchical heuristic to minimize energy consumption without violating performance constraints. We also demonstrate that such an approach reduces algorithmic complexity significantly. Results from hardware experiments show that in scenarios with low consolidation ratios energy savings range from 3% to 6%, while for high consolidation ratios they range from 11% to 25%. In all cases, the measured end-to-end performance penalty is minimal.

Rocks are heterogeneous multiscale porous media: two rock samples with identical bulk properties can vary widely in microstructure. The advent of digital rock technology and modern 3-D printing provides new opportunities to replicate rocks. However, the inherent trade-off between imaging resolution and sample size limits the scales over which microstructure and macrostructure can be identified and related to each other. Here, we develop a multiscale digital rock construction strategy by combining X-ray computed microtomography and focused-ion beam (FIB)-scanning electron microscope (SEM) images, and we apply the technique to a tight sandstone. The computed tomography (CT) scanning images characterize macroscale pore structures, while the FIB-SEM images capture microscale pore textures. The FIB-SEM images are then coupled to CT images via a template-matching algorithm and superposition. Bulk properties, including porosity and pore and throat size distribution, can be recovered with this approach. Permeability prediction with a pore network model for the largest connected pore network are 3 orders and 1 order of magnitude greater than the bulk rock measured value using the CT-only and the SEM-CT coupled images, respectively.

Electrochemical conversion of small molecules such as carbon dioxide (CO2) and carbon monoxide (CO) to high-value multi-carbon products (C2+) offers a chemical upgrade approach for fuels and chemical feedstock production using renewable energy, in the possible absence of the petrochemical industry under the new energy system such as hydrogen economy. Identifying robust and efficient electrocatalysts to selectively produce C2+ products remains a challenge. Herein, we report a synthetic strategy of atomically dispersing copper atoms on nitrogen-rich porous carbon (Cu–N–C) through pyrolysis of a supramolecular assembly. Benefitting from the unsaturated coordination structure, in KOH electrolyte, the Cu–N–C with a Cu content of 6.9 wt% exhibits a maximum acetate Faradaic efficiency (FE) of 30% with an acetate partial current density as high as 48 mA cm−2 in electrochemical CO reduction. Different from the C–C coupling mechanism on metallic copper, we propose a CO insertion mechanism for the acetate production on the single site copper catalyst.

We present a measurement of the branching fraction for the decay of the neutral B meson into the final state J/psipi(+)pi(-). The data set contains approximately 56 x 10(6) BB pairs produced at the Upsilon(4S) resonance and recorded with the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) storage ring. The result of this analysis is B(B0-->J/psipi(+)pi(-))=(4.6+/-0.7+/-0.6) x 10(-5), where the first error is statistical and the second is systematic. In addition, we measure B(B0-->J/psirho(0))=(1.6+/-0.6+/-0.4) x 10(-5).