Inorganic Halide Perovskite Nanowires/Conjugated Polymer Heterojunction-Based Optoelectronic Synaptic Transistors for Dynamic Machine Vision.

Inspired by the retina, artificial optoelectronic synapses have groundbreaking potential for machine vision. The field-effect transistor is a crucial platform for optoelectronic synapses that is highly sensitive to external stimuli and can modulate conductivity. On the basis of the decent optical absorption, perovskite materials have been widely employed for constructing optoelectronic synaptic transistors. However, the reported optoelectronic synaptic transistors focus on the static processing of independent stimuli at different moments, while the natural visual information consists of temporal signals. Here, we report CsPbBrI2 nanowire-based optoelectronic synaptic transistors to study the dynamic responses of artificial synaptic transistors to time-varying visual information for the first time. Moreover, on the basis of the dynamic synaptic behavior, a hardware system with an accuracy of 85% is built to the trajectory of moving objects. This work offers a new way to develop artificial optoelectronic synapses for the construction of dynamic machine vision systems.

A conductive catecholate-based framework coordinated with unsaturated bismuth boosts CO2 electroreduction to formate.

Bismuth-based metal-organic frameworks (Bi-MOFs) have received attention in electrochemical CO2-to-formate conversion. However, the low conductivity and saturated coordination of Bi-MOFs usually lead to poor performance, which severely limits their widespread application. Herein, a conductive catecholate-based framework with Bi-enriched sites (HHTP, 2,3,6,7,10,11-hexahydroxytriphenylene) is constructed and the zigzagging corrugated topology of Bi-HHTP is first unraveled via single-crystal X-ray diffraction. Bi-HHTP possesses excellent electrical conductivity (1.65 S m-1) and unsaturated coordination Bi sites are confirmed by electron paramagnetic resonance spectroscopy. Bi-HHTP exhibited an outstanding performance for selective formate production of 95% with a maximum turnover frequency of 576 h-1 in a flow cell, which surpassed most of the previously reported Bi-MOFs. Significantly, the structure of Bi-HHTP could be well maintained after catalysis. In situ attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) confirms that the key intermediate is *COOH species. Density functional theory (DFT) calculations reveal that the rate-determining step is *COOH species generation, which is consistent with the in situ ATR-FTIR results. DFT calculations confirmed that the unsaturated coordination Bi sites acted as active sites for electrochemical CO2-to-formate conversion. This work provides new insights into the rational design of conductive, stable, and active Bi-MOFs to improve their performance towards electrochemical CO2 reduction.

Preparing Thick Gradient Surface Layer in Cu-Zn Alloy via Ultrasonic Severe Surface Rolling for Strength-Ductility Balance.

A gradient structure (GS) design is a prominent strategy for strength-ductility balance in metallic materials, including Cu alloys. However, producing a thick GS surface layer without surface damage is still a challenging task limited by the available processing technology. In this work, a gradient structure (GS) surface layer with a thickness at the millimeter scale is produced in the Cu-38 wt.% Zn alloy using ultrasonic severe surface rolling technology at room temperature. The GS surface layer is as thick as 1.1 mm and involves the gradient distribution of grain size and dislocation density. The grain size is refined to 153.5 nm in the topmost surface layer and gradually increases with increasing depth. Tensile tests indicate that the single-sided USSR processed alloy exhibits balanced strength (467.5 MPa in yield strength) and ductility (10.7% in uniform elongation). Tailoring the volume fraction of the GS surface layer can tune the combination of strength and ductility in a certain range. The high strength of GS surface layer mainly stems from the high density of grain boundaries, dislocations and dislocation structures, deformation twins, and GS-induced synergistic strengthening effect. Our study elucidates the effect of the thick GS surface layer on strength and ductility, and provides a novel pathway for optimizing the strength-ductility combination of Cu alloys.

Polymer-Assisted Space-Confined Strategy for the Foot-Scale Synthesis of Flexible Metal-Organic Framework-Based Composite Films.

At the gas-liquid interface, the confined synthesis of metal-organic framework (MOF) films has been extensively developed by spreading an ultrathin oil layer on the aqueous surface as a reactor. However, this interface is susceptible to various disturbances and incapable of synthesizing large-area crystalline MOF films. Herein, we developed a polymer-assisted space-confined strategy to synthesize large-area films by blending poly(methyl methacrylate) (PMMA) into the oil layer, which improved the stability of the gas-liquid interface and the self-shrinkage of the oil layer on the water surface. Meanwhile, the as-synthesized MOFs as a quasi-solid substrate immobilized the edge of the oil layer, which maintained a large spreading area. Thanks to this synergistic effect, we synthesized the freestanding MOF-based film with a foot-level (0.66 ft) lateral dimension, which is the largest size reported so far. Besides, due to the phase separation of the two components, the MOF-PMMA composite film combined the conductivity of MOFs (1.13 S/m) with the flexibility of PMMA and exhibited excellent mechanical properties. More importantly, this strategy could be extended to the preparation of other MOFs, coordination polymers (CPs), and even inorganic material composite films, bringing light to the design and large-scale synthesis of various composite films for practical applications.

Ultrastable Laurionite Spontaneously Encapsulates Reduced-dimensional Lead Halide Perovskites.

Reduced dimensional lead halide perovskites (RDPs) have attracted great research interest in diverse optical and optoelectronic fields. However, their poor stability is one of the most challenging obstacles prohibiting them from practical applications. Here, we reveal that ultrastable laurionite-type Pb(OH)Br can spontaneously encapsulate the RDPs in their formation solution without introducing any additional chemicals, forming RDP@Pb(OH)Br core-shell microparticles. Interestingly, the number of the perovskite layers within the RDPs can be conveniently and precisely controlled by varying the amount of CsBr introduced into the reaction solution. A single RDP@Pb(OH)Br core-shell microparticle composed of RDP nanocrystals with different numbers of perovskite layers can be also prepared, showing different colors under different light excitations. More interestingly, barcoded RDP@Pb(OH)Br microparticles with different parts emitting different lights can also be prepared. The morphology of the emitting microstructures can be conveniently manipulated. The RDP@Pb(OH)Br microparticles demonstrate outstanding environmental, chemical, thermal, and optical stability, as well as strong resistance to anion exchange processes. This study not only deepens our understanding of the reaction processes in the extensively used saturation recrystallization method but also points out that it is highly possible to dramatically improve the performance of the optoelectronic devices through manipulating the spontaneous formation process of Pb(OH)Br.

[Meridian differentiation of low back pain in Neijing (Inner Canon of Yellow Emperor)].

There are various contents about diagnosis and treatment of low back pain in Neijing (Inner Canon of Yellow Emperor), which are closely related to meridians and collaterals, forming a complete theoretical system of meridian differentiation for low back pain. Its theory and application are interpreted in this paper from five main aspects, including 18 meridians and collaterals densely distributing in the tendons and bones of the waist, the pathogenesis of low back pain lying in the disorders of the meridian qi and blood, the nature of low back pain being reflected by the color and shape of meridians and collaterals, the disordered meridians of low back pain being first identified based on syndrome differentiation, the acupuncture prescription being selected according to meridian differentiation. The purpose of this paper is to guide clinical practice, explore the advantages and characteristics of meridian differentiation, and provide theoretical reference and evidence for promoting the standardization of TCM.

[Hypothalamic Transcription Profiles Associated with Twirling-reducing Needling in Rats with Stress-induced Prehypertension].

OBJECTIVE: To observe the effect of twirling-reducing needling on changes of profile of differentially-expressed genes in the hypothalamus in rats with stress-induced prehypertension (SI-PHT), so as to explore its mechanism under-lying improvement of prehypertension. METHODS: Wistar male rats were randomly divided into blank control group (n=12), model group (n=12) and acupuncture group (n=10). The SI-PHT model was established by planta-electric-shock stimulation (30 V, 5 s) plus noise stimulation (80-100 db, 50 ms), twice daily, continuously for 11 days. Manual acupuncture stimulation (twirling-reducing needling) was applied to bilateral "Taichong" (LR 3) and "Quchi" (LI 11) for about 1 min (60 cycles/min), followed by retaining the needles for 20 min during modeling preparation, once daily for 11 days. The systolic blood pressure (SBP) and behavior changes were recorded before intervention and on the 3rd, 5th, 7th, 9th and 11th day during modeling. The expression (Fold change,|FC| ≥ 1.5) profile of genes in the hypothalamus was analyzed using Affymetrix GeneChip Rat Gene 2.0 ST Array, followed by analyzing the differentially-expressed genes involving the related biological process,molecular function, and signaling pathways by using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), separately. RESULTS: After modeling, the systolic pressure levels were remarkably increased from the 3rd day to the 11th day in both model and acupuncture groups relatively to their respective baseline levels (P<0.01), and were significantly lower in the acupuncture group than in the model group (P<0.01) from the 5th day to the 11th day. Meanwhile, 93 genes were up-regulated and 153 down-regulated in the model group relative to the control group (P<0.05,|FC| ≥ 1.5), while in comparison with the model group, 59 genes were up-regulated and 86 down-regulated in the acupuncture group (P<0.05,|FC| ≥ 1.5). The expression levels of the 40 differen-tially-expressed genes (24 up-regulated and 16 down-regulated) in the model group were evidently reversed after acupuncture stimulation (P<0.05,|FC| ≥ 1.5). After acupuncture stimulation, the expression of acyl-CoA synthetase medium-chain family member 3 (Acsm 3) gene was down-regulated, and chorionic gonadotropin-alpha (Cgα), crystal (Cry) αB and thyroid stimulating hormone beta (Tshß) genes and the autoimmune thyroid disease (AITD) pathway were up-regulated (P<0.05,|FC| ≥ 1.5), suggesting an involvement of fatty acid biosynthetic processing, G-protein coupled receptor protein signaling, and hormone activity, etc. in acupuncture-induced blood-pressure lowering. CONCLUSIONS: Twirling-reducing needling of acupuncture can lower blood pressure in prehypertension rats, which may be related to its effects in regulating expression of Acsm 3, Cgα, CryαB, Tshß genes and in activating AITD pathway.

[Application of gene chip technology for acupuncture research over the past 15 years].

To explore the application of gene chip technology in the acupuncture research so as to provide evidences for the mechanism of acupuncture for regulating bodies. The literature on the application of gene chip technology in the acupuncture field from 2001 to 2016 was collected in PubMed, Springer, CNKI and WANFANG databases, which was analyzed and summarized. There were some achievements of the technology for acupuncture research, focusing on the five aspects, including the study of the relationship between meridian-point and viscera, the influencing factors of acupuncture effect, the effect and mechanism of acupuncture analgesia, the mechanism of acupuncture anti-aging, the effect and mechanism of acupuncture for diseases of each system. Gene chip technology plays an important role in researching acupuncture mechanism. It is an important technology for genomics study of acupuncture. However, there are also some disadvantages such as high cost, deficient data mining, non-uniform observation objects, deficient professionals, etc. All those need further resolution so as to promote the application of this technology in the acupuncture researching field.

Warm white light generation from a single phase Dy3+ doped Mg2Al4Si5O18 phosphor for white UV-LEDs.

A series of Mg2-xAl4Si5O18:xDy(3+) (0 ≤x≤ 0.18) samples were synthesized, for the first time, by a solid state method both in a reducing atmosphere and in air. XRD, diffuse reflectance spectra, excitation spectra, emission spectra, decay times and thermal quenching were used to investigate the structure, photoluminescence, energy transfer and thermal properties. The results show that Mg2Al4Si5O18:Dy(3+) can efficiently absorb UV light and emit violet-blue light in the range of 400 to 500 nm from oxygen vacancies in the host as well as blue light (∼480 nm) and yellow light (∼576 nm) from the f-f transitions of Dy(3+). The emission intensities of the samples obtained under a reducing atmosphere are far superior to those of the samples obtained in air due to an efficient energy transition from oxygen vacancies in the host to Dy(3+). An analysis of the thermal quenching shows that the phosphor Mg2Al4Si5O18:Dy(3+) has excellent thermal properties. The emission intensities of typical samples synthesized in a reducing atmosphere and in air at 250 °C are 70% and 81% of their initial intensities at 20 °C, respectively. In addition, the emission colors of all of the samples are located in the white light region and the optimal chromaticity coordinates and Correlated Color Temperature are (x = 0.34, y = 0.33) and 5129 K, respectively. Therefore, these white Mg2Al4Si5O18:Dy(3+) phosphors could serve as promising candidates for white-light UV-LEDs.