Single atom doping induced charge-specific distribution of Cu1-TiO_(2) for selective aniline oxidation via a new mechanism

Utilizing single atom sites doping into metal oxides to modulate their intrinsic active sites,achieving precise selectivity control in complex organic reactions,is a highly desirable yet challenging endeavor.Meanwhile,identifying the active site also represents a significant obstacle,primarily due to the intricate electronic environment of single atom site doped metal oxide.Herein,a single atom Cu doped TiO_(2)catalyst(Cu_(1)-TiO_(2)) is prepared via a simple“colloid-acid treatment”strategy,which switches aniline oxidation selectivity of TiO_(2) from azoxybenzene to nitrosobenzene,without using additives or changing solvent,while other metal or nonmetal doped TiO_(2) did not possess.Comprehensive mechanistic investigations and DFT calculations unveil that Ti-O active site is responsible for triggering the aniline to form a new PhNOH intermediate,two PhNOH condense to azoxybenzene over TiO_(2) catalyst.As for Cu_(1)-TiO_(2),the charge-specific distribution between the isolated Cu and TiO_(2) generates unique Cu_(1)-O-Ti hybridization structure with nine catalytic active sites,eight of them make PhNOH take place spontaneous dissociation to produce nitrosobenzene.This work not only unveils a new mechanistic pathway featuring the PhNOH intermediate in aniline oxidation for the first time but also presents a novel approach for constructing single-atom doped metal oxides and exploring their intricate active sites.

Exercise-induced irisin in bone and systemic irisin administration reveal new regulatory mechanisms of bone metabolism

Irisin is a polypeptide hormone derived from the proteolytic cleavage of fibronectin-type III domain- containing 5 （FNDC5） protein. Once released to circulation upon exercise or cold exposure, irisin stimulates browning of white adipose tissue （WAT） and uncoupling protein I （UCP1） expression, leading to an increase in total body energy expenditure by augmented UCPl-mediated thermogenesis. It is currently unknown whether irisin is secreted by bone upon exercise or whether it regulates bone metabolism in vivo. In this study, we found that 2 weeks of voluntary wheel-running exercise induced high levels of FNDC5 messenger RNA as well as FNDC5/irisin protein expression in murine bone tissues. Increased immunoreactivity due to exercise-induced FNDC5/irisin expression was detected in different regions of exercised femoral bones, including growth plate, trabecular bone, cortical bone, articular cartilage, and bone-tendon interface. Exercise also increased expression of osteogenic markers in bone and that of UCP1 in WAT, and led to bodyweight loss. Irisin intraperitoneal （IP） administration resulted in increased trabecular and cortical bone thickness and osteoblasts numbers, and concurrently induced UCP1 expression in subcutaneous WAT. Lentiviral FNDC5 IP administration increased cortical bone thickness. In vitro studies in bone cells revealed irisin increases osteoblastogenesis and mineralization, and inhibits receptor activator of nuclear factor-kB ligand （RANKL）- induced osteoclastogenesis. Taken together, our findings show that voluntary exercise increases irisin production in bone, and that an increase in circulating irisin levels enhances osteogenesis in mice.

INVESTIGATION ON THE NEW SYNTHETIC REACTIONS AND MECHANISMS OF SUBSTITUTED DIPHENYL ETHEPS

In the presence of alkali nitrite and carbonate,some nitrobenzenes subs- tituted by strongly electron withdrawing group undergo a self condensation in an aprotic polar sotvent to give symmetrical disubstituted diphenyl ethers in good yields.A possible mechanism is discussed,the nucteophilic aromatic substitution S_NAr and S_(Ru)Ar may occur simultaneously.

MECHANISM OF ELECTROCHEMILUMINESCENCE OF THE NEW REAGENT 6-(2-HYDROXY-DIETHYLAMINOPHENYLAZO)-2, 3-DIHYDRO-1, 4-PHTHALAZINE-1, 4-DIONE CATALYZED BY SILVER (Ⅰ)

The electrochemi luminescence <ecl> of a new reagent 6-<2-hydroxy-4-diethylaminophenylazo>-2, 3-dihydro-1, 4-phthatazine-1, 4-dione <HDEA> in basic aqueous solution was studied. Trace amount of silver showed significant effect on the efficiency of light emission of HDEA during a positive trigonometrical wave pulse was exerted on the electrodes In the present paper, the ecl spectra of HDEA have been measured. λ_(max) is 410 nm. The reaction of HDEA chemiluminescence and the circular voltammetry, ultraviolet-visible spectrometry for the system have been investigated. The possible mechanism of the ecl of HDEA-KCL-KOH-Ag(I) system has been proposed.

Welcome to subscribe to the new journal Journal of Rock Mechanics and Geotechnical Engineering

Journal of Rock Mechanics and Geotechnical Engineering（JRMGE）is a new academic publication in English launched in 2009,co-sponsored by Institute of Rock and Soil Mechanics,China Academy of Sciences,Chinese Society for Rock Mechanics and Engineering and Wuhan University.

A new mechanism found for the pathogenesis of Alzheimer’s

CAS scientists recently discovered that activation of a protein called β2-adrenergic receptor may lead to the abnormal formation of the amyloid plaques, which are believed to be the hallmark and primary cause of Alzheimer's disease.

Concise Strategies to Enhance the High-Rate Performance of Li_(3)VO_(4) Anodes:Cl Doping,Carbon Coating,and Spherical Architecture Design

The safe operating voltage and low volume variation of Li_(3)VO_(4)(LVO)make it an ideal anode material for lithium(Li)-ion batteries.However,the insufficient understanding of the inner storage mechanism hinders the design of LVO-based electrodes.Herein,we investigate,for the first time,the Li-ion storage activity in LVO via Cl doping.Moreover,N-doped C coating was simultaneously achieved in the Cl doping process,resulting in synergistically improved reaction kinetics.As a result,the as-prepared Cl-doped Li_(3)VO_(4) coated with N-doped C(Cl-LVO@NC)electrodes deliver a discharge capacity of 884.1 mAh/g after 200 cycles at 0.2 A/g,which is the highest among all of the LVO-based electrodes.The Cl-LVO@NC electrodes also exhibit high-capacity retention of 331.1 mAh/g at 8.0 A/g and full capacity recovery after 5 periods of rate testing over 400 cycles.After 5000 cycles at 4.0 A/g,the discharge capacity can be maintained at 423.2 mAh/g,which is superior to most LVO-based electrodes.The Li-ion storage activity in LVO via Cl doping and significant improvement in the high-rate Li-ion storage reported in this work can be used as references for the design of advanced LVO-based electrodes for high-power applications.

Dual-ionic imidazolium salts to promote synthesis of cyclic carbonates at atmospheric pressure

Novel dual-ionic imidazolium salts are shown to display excellent catalytic activity for cycloaddition of carbon dioxide and epoxides under room temperature and atmospheric pressure(0.1 MPa)without any solvent and co-catalyst leading to 96.1%product yield.It can be reused five times to keep the product yield over 90%.These intriguing results are attributed to a new reaction mechanism,which is supported by theoretical calculations along with the measurements of ^(13)C NMR spectrum and Fourier transform infrared spectroscopy(FT-IR).The excellent catalytic activity can be traced to a CO_(2)-philic group along with an electrophilic hydrogen atom.Our work shows that incorporation of CO_(2)-philic group is an feasible pathway to develop the new efficient ionic liquids.

ANALYZING ON THE VIBRATION CHARACTERISTICS OF A MICRO PIEZOELECTRIC ROBOT IN PIPELINE

The mathematical model of a micro piezoelectric elastic legged robot in pipeline was founded. The robotic resonant frequency worked out with the mathematical model is nearly equal to the frequency from experiment. It indicates that the mathematical model of the robot is correct. Besides, it studied the piezoelectric robotic structure parameters’ effect on the robotic performance. The result of the analysis on the robot constructs the base of an optimal design of a piezoelectric robot.

Mutant p53 promotes cell spreading and migration via ARHGAP44

The tumor suppressor p53 protein is either lost or mutated in about half of all human cancers.Loss of p53 function is well known to influence cell spreading,migration and invasion.While expression of mutant p53 is not equivalent to p53 loss,mutant p53 can acquire new functions to drive cell spreading and migration via different mechanisms.In our study,we found that mutant p53 significantly increased cell spreading and migration when comparing with p53-null cells.RNA-Seq analysis suggested that Rho GTPase activating protein 44(ARHGAP44) is a new target of mutant p53,which suppressed AKHGAP44 transcription.ARHGAP44 has GAP activity and catalyze GTP hydrolysis on Cdc42.Higher level of GTP-Cdc42 was correlated with increase expression of mutant p53 and reduced ARHGAP44.Importantly,wt-ARHGAP44 but not mutant ARHGAP44(R291A) suppressed mutant p53 mediated cell spreading and migration.Bioinformatics analysis indicated lower expression of ARHGAP44 in lung carcinoma compared with normal tissues,which was verified by RT-qPCR using specimens from patients.More interestingly,ARHGAP44 mRNA level was lower in tumors with mutant p53 than those with normal p53.Collectively,our results disclose a new mechanism by which mutant p53 stimulates cell spreading and migration.