Study of photon detection efficiency and position resolution of BESIII electromagnetic calorimeter

We study the photon detection efficiency and position resolution of the electromagnetic calorimeter (EMC) of the BESIII experiment. The control sample of the initial-state-radiation (ISR) process of $e^+e^-\rightarrow \gamma \mu^+\mu^-$ is used at $J/\psi$ and $\psi(3770)$ resonances for the EMC calibration and photon detection efficiency study. Photon detection efficiency is defined as the predicted photon, obtained by performing a kinematic fit with two muon tracks, matched with real photons in the EMC. The spatial resolution of the EMC is defined as the separation in polar ($\theta$) and azimuthal ($\phi$) angles between charged track and associated cluster centroid on the front face of the EMC crystals.Comment: 5 page

Giant room-temperature spin caloritronics in spin-semiconducting graphene nanoribbons

pre-printSpin caloritronics refers to generating spin current by thermal gradient. Here we report a theoretical study demonstrating giant spin caloritronic effects in a new class of materials, called spin semiconductors, which are characterized with a "spin gap," the energy gap between spin-up and -down channels. Generally, spin Seebeck coefficient (Ss ) is shown to increase linearly with the spin gap. Specifically, unprecedented large Ss ∼ 3.4 mV/K and spin figure of merit ZsT ∼ 119 were found in spin-semiconducting graphene nanoribbons (GNRs) with sawtooth (ST) zigzag edges, based on first-principles calculations. Such giant spin caloritronic effects are shown to originate from a large spin gap of ST GNRs, in addition to two other spin-independent features of large band gap and narrow bandwidth which are commonly known for good thermoelectric materials. Our studies suggest that spin-semiconducting nanostructures, such as ST GNRs, are promising candidates for room-temperature spin caloritronics with high efficiency

The Important Functions of GSH-Dependent Enzyme Glutaredoxin 2 (Grx2)

Reactive oxygen species (ROS) are generated at a very high rate throughout our lives as part of normal aerobic life. Glutathione (GSH), normally an antioxidant molecule that scavenges free radicals, oxidizes to form glutathione mixed disulfide (GSSG). As the GSSG/GSH ratio increases, GSSG naturally adds to other proteins, causing protein glutathionylation. Protein glutathionylation, defined as the reversible formation of a mixed disulfide (PSSG) between protein thiols (P-SH) and glutathione (GSH), appears to be the most important mode of thiol oxidation. In my chapter, we will discuss the important roles of GSH and GSH-dependent enzymes in health and disease, with the emphasis on glutaredoxin and thioredoxin systems. Their structures, catalytic reaction mechanisms, major physiological functions, and associations with diseases will be summarized in my chapter. We will also mention how GSH-dependent enzymes play a role in each major organ systems including the nervous, cardiovascular, immune, and visual system