Repeated methamphetamine exposure decreases plasma brain-derived neurotrophic factor levels in rhesus monkeys

Background Brain-derived neurotrophic factor(BDNF)is known to prevent methamphetamine(METH)-induced neurotoxicity and plays a role in various stages of METH addiction.However,there is a lack of research with longitudinal design on changes in plasma BDNF levels in active METH-dependent individuals.Aims The aim of the study was to investigate changes in BDNF levels during METH self-administration in monkeys.Methods This study measured plasma BDNF levels in three male rhesus monkeys with continuous METH exposure and four male control rhesus monkeys without METH exposure.Changes in plasma BDNF levels were then assessed longitudinally during 40 sessions of METH self-administration in the three monkeys.Results Repeated METH exposure decreased plasma BDNF levels.Additionally,plasma BDNF decreased with long-term rather than short-term accumulation of METH during METH self-administration.Conclusions These findings may indicate that the changes in peripheral BDNF may reflect the quantity of accumulative METH intake during a frequent drug use period.

New Inverse Method for Determining Uniaxial Flow Properties by Spherical Indentation Test

The spherical indentation test has been successfully applied to inversely derive the tensile properties of small regions in a non-destructive way.Current inverse methods mainly rely on extensive iterative calculations,which yield a considerable computational costs.In this paper,a database method is proposed to determine tensile flow properties from a single indentation force-depth curves to avoid iterative simulations.Firstly,a database that contain numerous indentation force-depth curves is established by inputting varied Ludwic material parameters into the indentation finite elements model.Secondly,for a given experimental indentation curve,a mean square error(MSE)is designated to evaluate the deviation between the experimental curve and each curve in the database.Finally,the true stresses at a series of plastic strain can be acquired by analyzing these deviations.To validate this new method,three different steels,i.e.A508,2.25Cr1 Mo and 316L are selected.Both simulated indentation curves and experimental indentation curves are used as inputs of the database to inversely acquire the flow properties.The result indicates that the pro-posed approach provides impressive accuracy when simulated indentation curves are used,but is less accurate when experimental curves are used.This new method can derive tensile properties in a much higher efficiency compared with traditional inverse method and are therefore more adaptive to engineering application.

Single-atom Pd anchored in the porphyrin-center of ultrathin 2D-MOFs as the active center to enhance photocatalytic hydrogen-evolution and NO-removal

Single-atom catalysts were widely used to treat atmospheric pollution and alleviate energy crises through photocatalysis.However,how to prevent the aggregation of single atoms during the preparation and catalytic processes remained a great challenge.Herein,a novel ultrathin two-dimensional porphyrin-based single-atom photocatalyst Ti-MOF(abbreviated as TMPd)obtained through a simple hydrothermal synthesis strategy was used for photocatalytic hydrogen evolution and NO removal,in which the singleatom Pd tightly anchored in the center of porphyrin to ensure single-atom Pd stable existence.Compared with most reported MOFs-based photocatalysts,the TMPd showed an excellent hydrogen evolution rate(1.32 mmol g^(-1)h^(-1))and the NO removal efficiency(62%)under visible light irradiation.Aberrationcorrected high-angle annular dark-field scanning transmission electron microscope(HAADF-STEM)and synchrotron-radiation-based X-ray absorption fine-structure spectroscopy(XAFS)proved that pd in TMPd existed in an isolated state,and the atomic force microscope(AFM)proved the ultrathin morphology of TMPd.DFT calculations had demonstrated that single-atom Pd could serve as the active center and more effectively achieve electron transfer,indicating that single-atom Pd played a vital role in photocatalytic hydrogen evolution.In addition,a possible photocatalytic pathway of NO removal was proposed based on ESR and in-situ infrared spectra,in which the catalysts anchored with single-atom Pd could produce more active substances and more effectively oxidize NO to NO_(2)^(-)or NO_(3)^(-).The results suggested that coordinating single-atom metal species as the active site in the center of porphyrin could be a feasible strategy to obtain various ultrathin porphyrin-based single-atom photocatalysts to acquire excellent photocatalytic performance further.

Repairable,Recyclable,and Regenerable Macrocycle Organic Polymer

Covalent/metal organic frameworks are highly attractive due to their tunable structure and properties,and broad applications in multiple fields.However,they still suffer from numbers of drawbacks including low solubility,harsh synthesis and fabrication,and low mechanical flexibility.Herein,we report a new organic framework consisting of macrocycles and organic frames in its periodic structure,and denote it as macrocycle organic polymer(MOP).The size-tunable macrocycles containing peripheral furan units are synthesized by anionic ring-opening polymerization,which undergo a reversible Diels-Alde reaction with bismaleimide to generate/degrade MOPs at given temperatures.Relying on above features,MOPs exhibit excellent flexibility,healable ability and recycle ability.Interestingly,owing to the“living”nature of anionic ring-opening polymerization,MOPs can self-grow into bigger sizes in the presence of monomer and catalysis,analogs to the living creatures.Moreover,their high porosity and rich thioether structure enable them as good metal ion absorbers and promising applications in wearable electronics.

Processing and valorization of cellulose,lignin and lignocellulose using ionic liquids

Cellulose,lignin and lignocellulose are important bioresources in the nature.Their effective and environmentally friendly utilization not only reduces dependence on fossil resources but also protects the environment.Recently,a class of novel eco-friendly solvents,ionic liquids,is employed to dissolve and process these bioresources.In this mini-review,we summarized the recent advances of processing and valorization of cellulose,lignin and lignocellulose in ionic liquids.It is expected that this up-to-date survey provides a comprehensive information of this field,and accelerates the development and utilization of the renewable plant biomass resources.

Simultaneous Strain and Temperature Measurement Based on Chaotic Brillouin Optical Correlation-Domain Analysis in Large-Effective-Area Fibers

Chaotic Brillouin optical correlation domain analysis(BOCDA)has been proposed and experimentally demonstrated with the advantage of high spatial resolution.However,it faces the same issue of the temperature and strain cross-sensitivity.In this paper,the simultaneous measurement of temperature and strain can be preliminarily achieved by analyzing the two Brillouin frequencies of the chaotic laser in a large-effective-area fiber(LEAF).A temperature resolution of 1℃ and a strain resolution of 20μξ can be obtained with a spatial resolution of 3.9cm.The actual temperature and strain measurement errors are 0.37℃ and 10μξ,respectively,which are within the maximum measurement errors.

On extended state based Kalman filter for nonlinear time-varying uncertain systems with measurement bias

This paper addresses the state estimation for a class of nonlinear time-varying stochastic systems with both uncertain dynam-ics and unknown measurement bias.A novel extended state based Kalman filter(ESKF)algorithm is developed to estimate the original state,the uncertain dynamics and the measurement bias.It is shown that the estimation error of the proposed algorithm is bounded in the mean square sense.Also,the estimation of the measurement bias asymptotically converges to its true value,such that the infuence of measurement bias is eliminated.Furthermore,the asymptotic optimality of the estima-tion result is proved while the uncertain dynamics approaches to a constant vector.Finally,a simulation study for harmonic oscillator system model is provided to ilustrate the effectiveness of proposed method.

Stimuli-Responsive Molecules: Emerging Materials for Advanced Data-Encryption and Anti-Counterfeiting

Data security is a long-term challenge that spans the whole history of human society, particularly in the field of commercial activities and military actions. To date, a variety of data protection techniques have been developed. Early examples include watermarks and holograms.[1] Later, color-shifting inks and luminescent patterns had been developed as well.