Size-Controlled Large-Diameter and Few-Walled Carbon Nanotube Catalysts for Oxygen Reduction

We demonstrate a new strategy for tuning the size of large-diameter and few-walled nitrogen-doped carbon nanotubes (N-CNTs) from 50 to 150 nm by varying the transition metal (TM = Fe, Co, Ni or Mn) used to catalyze graphitization of dicyandiamide. Fe yielded the largest tubes, followed by Co and Ni, while Mn produced a clot-like carbon morphology. We show that morphology is correlated with electrocatalytic activity for the oxygen reduction reaction (ORR). A clear trend of Fe \u3e Co \u3e Ni \u3e Mn for the ORR catalytic activity was observed, in both alkaline media and more demanding acidic media. The Fe-derived N-CNTs exhibited the highest BET (∼870 m2 g−1) and electrochemically accessible (∼450 m2 g−1) surface areas and, more importantly, the highest concentration of nitrogen incorporated into the carbon planes. Thus, in addition to the intrinsic high activity of Fe-derived catalysts, the high surface area and nitrogen doping contribute to high ORR activity. This work, for the first time, demonstrates size-controlled synthesis of large-diameter N-doped carbon tube electrocatalysts by varying the metal used in N-CNT generation. Electrocatalytic activity of the Fe-derived catalyst is already the best among studied metals, due to the high intrinsic activity of possible Fe–N coordination. This work further provides a promising route to advanced Fe–N–C nonprecious metal catalysts by generating favorable morphology with more active sites and improved mass transfer

Myricetin alleviates H2O2-induced senescence and apoptosis in rat nucleus pulposus-derived mesenchymal stem cells

Introduction. Transplantation of mesenchymal stem cells (MSCs) has been reported to be a novel promising target for the regeneration of degenerated intervertebral discs (IVDs). However, the culture and survival limitations of MSCs remain challenging for MSC-based biological therapy. Myricetin, a common natural flavonoid, has been suggested to possess antiaging and antioxidant abilities. Therefore, we investigated the biological function of myricetin, and its related mechanisms involving cell senescence in intervertebral disc degeneration (IDD). Material and methods. The nucleus pulposus-derived mesenchymal stem cells (NPMSCs) were isolated from 4-month-old Sprague-Dawley (SD) rats and identified by examining surface markers and multipotent differentiation. Rat NPMSCs were cultured in an MSC culture medium or culture medium with different concentrations of H2O2. Myricetin or the combination of myricetin and EX527 were added to the culture medium to investigate the effects of myricetin. Cell viability was evaluated by cell counting kit-8 assays (CCK-8). The apoptosis rate was determined using Annexin V/PI dual staining. The mitochondrial membrane potential (MMP) was analyzed by a fluorescence microscope after JC-1 staining. The cell senescence was determined by SA-β-Gal staining. MitoSOX green was used to selectively estimate mitochondrial reactive oxygen species (ROS) Apoptosis-associated proteins (Bax, Bcl2, and cleaved caspase-3), senescence markers (p16, p21, and p53), and SIRT1/PGC-1α signaling pathway-related proteins (SIRT1 and PGC-1α) were evaluated by western blotting. Results. The cells isolated from nucleus pulposus (NP) tissues met the criteria for MSCs. Myricetin showed no cytotoxicity up to a concentration of 100 μM in rat NPMSCs cultured for 24 h. Myricetin pretreatment exhibited protective effects against H2O2-induced apoptosis. Myricetin could also alleviate H2O2-induced mitochondrial dysfunctions of increased mitochondrial ROS production and reduced MMP. Moreover, myricetin pretreatment delayed rat NPMSC senescence, as evidenced by decreased senescence indicators and reduced SA-β-Gal activity. Pretreatment of NPMSCs with 10 μM EX527, a selective inhibitor of SIRT1, prior to exposure to 100 μM H2O2, reversed the inhibitory effects of myricetin on cell apoptosis. Conclusions. Myricetin could affect the SIRT1/PGC-1α pathway to protect mitochondrial functions and alleviate cell senescence in H2O2-treated NPMSCs

A comparative study of prepulse inhibition in children with first episode schizophrenia and normal children

Objective·To explore the characteristics of sensory gating and its variation in children with first episode schizophrenia (COS) by using a new technique of prepulse suppression (PI).Methods·By using the ERP recording and analysis system of brain products, PI was detected in 56 patients with COS and 38 healthy children (NC) using the paradigm of single strong stimulus and weak stimulus+strong stimulus. The patients′ performance was comprehensively evaluated with Positive and Negative Syndrome Scale (PANSS), Social Disability Screening Schedule (SDSS), Social Adjustment Rating Scale (SSRS), and Family Interview Schedule (FIS).Results·The social objective support formed by summing up the above scales was compared with the quantitative stanard of social support [the standard of social support scale was (8±2) points, and the value of COS group was (10±3) points], and the difference was statistically significant (P=0.007). No correlation was found between PI and PANSS total score and each factor score (all P>0.05). The latency of startle reflex in the COS group was longer than that in the NC group [the NC group was (86±11) ms, the COS group was (97±13) ms, P=0.001]. In the COS group, the amplitude of startle reflex of weak stimulus+strong stimulus was higher, and the latency was longer than that of the NC group [NC group: (39±12) μV, COS group (47±21) μV, P=0.007; the latency of the normal group was (84±17) ms, and that of the COS group was (97±20) ms, P=0.003]. PI inhibition rate in the COS group was lower than that in the NC group [(66±32) % in the NC group, (43±37) % in the COS group, P=0.000].Conclusion·COS patients have the same PI abnormality as adult schizophrenia. The change of PI inhibition may be the result of biological markers reflecting the change of agitated emotion in COS patients

EchoAI: A deep-learning based model for classification of echinoderms in global oceans

IntroductionIn response to the need for automated classification in global marine biological studies, deep learning is applied to image-based classification of marine echinoderms.MethodsImages of marine echinoderms are collected and classified according to their systematic taxonomy. The images belong to 5 classes, 38 orders, 145 families, 459 genera, and 1021 species, respectively. The deep learning model, EfficientNetV2, outperforms the competing model and is chosen for developing the automated classification tool, EchoAI. Then, the EfficientNetV2-based tool, EchoAI is applied to each taxonomic level.ResultsThe accuracy for the test dataset was 0.980 (class), 0.876 (order), 0.738 (family), 0.612 (genus), and 0.469 (species), respectively. Online prediction service is provided.DiscussionThe EchoAI model and results are facilitated for investigating the diversity, abundance and distribution of species at the global scale, and the methodological strategy can also be applied to image classification of other categories of marine organisms, which is of great significance for global marine studies. EchoAI is freely available at http://www.csbio.sjtu.edu.cn/bioinf/EchoAI/ for academic use

Adding Spin Functionality to Traditional Optoelectronics via Chiral Perovskite

Spin polarized current generation and injection into semiconductors at room temperature are key to enable a broader range of opto-spintronic functionalities, yet the inherent efficiency of spin injection across commonly used semiconductor-ferromagnet interfaces is limited. Here, we demonstrate efficient spin injection into commercially viable III-V light emitting diodes (LED) by integrating chiral halide perovskite layers with (AlxGa1-x)0.5In0.5P multiple quantum wells (MQW). Spin polarized current is injected via chirality induced spin selectivity (CISS) and the spin accumulation in the III-V semiconductor is detected via the emission of circularly polarized light with a degree of circular polarization of up to ~ 15%. X-ray photoemission spectroscopy (XPS) and transmission electron microscopy (TEM) cross sectional imaging indicate a pristine perovskite/III-V interface. These findings demonstrate chiral perovskite semiconductors transform well-developed semiconductor platforms to enable control over spin, charge, and light

A simulation study on the measurement of D0-D0bar mixing parameter y at BES-III

We established a method on measuring the \dzdzb mixing parameter $y$ for BESIII experiment at the BEPCII $e^+e^-$ collider. In this method, the doubly tagged $\psi(3770) \to D^0 \overline{D^0}$ events, with one $D$ decays to CP-eigenstates and the other $D$ decays semileptonically, are used to reconstruct the signals. Since this analysis requires good $e/\pi$ separation, a likelihood approach, which combines the $dE/dx$, time of flight and the electromagnetic shower detectors information, is used for particle identification. We estimate the sensitivity of the measurement of $y$ to be 0.007 based on a $20fb^{-1}$ fully simulated MC sample.Comment: 6 pages, 7 figure

Genome encode analyses reveal the basis of convergent evolution of fleshy fruit ripening

Altres ajuts: Generalitat de Catalunya/CERCA ProgrammeFleshy fruits using ethylene to regulate ripening have developed multiple times in the history of angiosperms, presenting a clear case of convergent evolution whose molecular basis remains largely unknown. Analysis of the fruitENCODE data consisting of 361 transcriptome, 71 accessible chromatin, 147 histone and 45 DNA methylation profiles reveals three types of transcriptional feedback circuits controlling ethylene-dependent fruit ripening. These circuits are evolved from senescence or floral organ identity pathways in the ancestral angiosperms either by neofunctionalisation or repurposing pre-existing genes. The epigenome, H3K27me3 in particular, has played a conserved role in restricting ripening genes and their orthologues in dry and ethylene-independent fleshy fruits. Our findings suggest that evolution of ripening is constrained by limited hormone molecules and genetic and epigenetic materials, and whole-genome duplications have provided opportunities for plants to successfully circumvent these limitations