Imaging Neural Activity in the Primary Somatosensory Cortex Using Thy1-GCaMP6s Transgenic Mice

The mammalian brain exhibits marked symmetry across the sagittal plane. However, detailed description of neural dynamics in symmetric brain regions in adult mammalian animals remains elusive. In this study, we describe an experimental procedure for measuring calcium dynamics through dual optical windows above bilateral primary somatosensory corticies (S1) in Thy1-GCaMP6s transgenic mice using 2-photon (2P) microscopy. This method enables recordings and quantifications of neural activity in bilateral mouse brain regions one at a time in the same experiment for a prolonged period in vivo. Key aspects of this method, which can be completed within an hour, include minimally invasive surgery procedures for creating dual optical windows, and the use of 2P imaging. Although we only demonstrate the technique in the S1 area, the method can be applied to other regions of the living brain facilitating the elucidation of structural and functional complexities of brain neural networks

Biogas slurry as an alternative to chemical fertilizer: Changes in soil properties and microbial communities of fluvo-aquic soil in the North China Plain

Biogas slurry application offers an alternative to chemical fertilizer in realizing ecologically re-cycling agriculture. However, the responses of soil fertility and microbial communities to long term use of biogas slurry need to be explored in different soil types and regions. We investigated the effects of repeated applications over six years on the soil properties and microbial character-istics of a fluvo-aquic soil in the North China Plain. The experiment, with equivalent nitrogen in-puts, comprised: biogas slurry (BS), chemical fertilizer (CF) or substitution of half the chemical fertilizer with biogas slurry (BSCF); a control treatment had no fertilizer addition. Soil samples, at a depth of 0–20 cm, were collected for their physicochemical properties. Microbial community diversity and composition was investigated using high-throughput sequencing. Biogas slurry ap-plication treatments tended to lower the soil bulk density while increasing the water-holding ca-pacity and the water-stable aggregate mean weight diameter. Organic carbon and available nu-trient concentrations (nitrogen, potassium and phosphorus) were enhanced in all fertilization treatments relative to the control, especially in the BSCF treatment. Significant differences in mi-crobial community composition were detected between the control and all of the fertilization treatments. BSCF resulted in the greatest diversity and most evenly balanced assemblages of both bacteria and fungi at the phylum level. There were clear associations between microbial composi-tion and changes in soil environmental variables caused by the fertilization treatments. Bacterial community composition and alpha diversity were associated particularly with differences in soil total nitrogen, pH, and available potassium, whereas fungal communities were more related to available potassium. Half substitution of the chemical fertilizer by biogas slurry gave the greatest improvement in soil structure and nutrient availability and this was associated with greater microbial diversity and better balanced microbial communities. Our results suggest that partial substitution with biogas slurry is an alternative to complete chemical fertilizer and that it offers clear benefits for the topsoil structure and fertility in fluvo-aquic soils. It also represents a prom-ising approach to a biogas-linked agroecosystem that restores sustainable coordination between cropping and animal husbandry under an intensive production regime

Mesoporous Spherical Silica Filler Prepared from Coal Gasification Fine Slag for Styrene Butadiene Rubber Reinforcement and Promoting Vulcanization

Coal gasification fine slag (CFS) is a solid contaminant produced by an entrained flow gasifier, which pollutes fields and the air in the long term. CFS is a potential polymer reinforcement filler and has been used in polypropylene and acrylonitrile butadiene styrene resins. Coal gasification fine slag mesoporous silica (FS-SiO2) was prepared by acid leaching, calcination, and pH adjustment, with a larger specific surface area and less surface hydroxyl compared to the commercial precipitated silica (P-silica). The cure characteristics, crosslink density, mechanical properties, the morphology of the tensile fractures, dynamic mechanics, and rubber processing of the prepared styrene butadiene rubber (SBR) composites filled with P-silica and FS-SiO2 were analyzed, respectively. The results indicated that FS-SiO2 was dispersed more uniformly in the SBR matrix than P-silica owing to its smaller amount of surface hydroxyl and spherical structure, resulting in a better mechanical performance and wet skid resistance. In particular, the SBR composites with a filler pH of 6.3 exhibited the highest crosslink density and tensile strength, being superior to commercial P-silica. Significantly, the curing time decreased with the increase in the pH of FS-SiO2, which caused the rubber processing to be more efficient. This strategy can reduce the cost of rubber composites and the environmental pollution caused by CFS

Safety evaluation of urban underground utility tunnel with the grey clustering method based on the whole life cycle theory

The construction of urban underground utility tunnel is a complicated process. With the rapid development of urbanization in China, the safety problem of utility tunnel is becoming more and more prominent. To evaluate the safety of utility tunnel, this study proposed an evaluation model based on the whole life cycle theory. Firstly, combining with the characteristics of utility tunnel, the construction period was divided into four phases: preliminary planning, design, construction and operation and maintenance. Through literature analysis and expert investigation method, 26 evaluation indices were selected, and the whole life cycle safety evaluation index system of urban underground utility tunnel was established; Secondly, the entropy weight method was used to determine the weight of each index; Thirdly, in order to evaluate the security of the utility tunnel in the whole life cycle, a grey clustering evaluation model was constructed. Finally, a case study was conducted to explain the application of the proposed model and to verify the validity of the model, the results indicated that the model could provide a new way to evaluate the safety state of the utility tunnel project

The brain network in support of social semantic accumulation

Some studies have indicated that a specific 'social semantic network' represents the social meanings of words. However, studies of the comprehension of complex materials, such as sentences and narratives, have indicated that the same network supports the online accumulation of connected semantic information. In this study, we examined the hypothesis that this network does not simply represent the social meanings of words but also accumulates connected social meanings from texts. We defined the social semantic network by conducting a meta-analysis of previous studies on social semantic processing and then examined the effects of social semantic accumulation using a functional Magnetic Resonance Imaging (fMRI) experiment. Two important findings were obtained. First, the social semantic network showed a stronger social semantic effect in sentence and narrative reading than in word list reading, indicating the amplitude of social semantic activation can be accumulated in the network. Second, the activation of the social semantic network in sentence and narrative reading can be better explained by the holistic social-semantic-richness rating scores of the stimuli than by those of the constitutive words, indicating the social semantic contents can be integrated in the network. These two findings convergently indicate that the social semantic network supports the accumulation of connected social meanings

Facile Fabrication of Diatomite-Supported ZIF-8 Composite for Solid-Phase Extraction of Benzodiazepines in Urine Samples Prior to High-Performance Liquid Chromatography

A novel diatomite-supported zeolitic imidazolate framework-8 sorbent (ZIF-8@Dt-COOH) was in situ fabricated and developed for solid-phase extraction of three benzodiazepines (triazolam, midazolam and diazepam) in urine followed by high-performance liquid chromatography. ZIF-8@Dt-COOH was easily prepared by coating ZIF-8 on the surface of Dt-COOH and characterized by Fourier transform infrared spectra, X-ray powder diffractometry and scanning electron microscopy. Compared with bare Dt-COOH, the extraction efficiency of ZIF-8@Dt-COOH for the target was significantly increased from 20.1–39.0% to 100%. Main extraction parameters, including ionic strength and pH of solution, loading volume, washing solution, elution solvent and elution volume, were optimized in detail. Under optimum conditions, the developed method gave linearity of three BZDs in 2–500 ng/mL (r ≥ 0.9995). Limits of detection (S/N = 3), and limits of quantification (S/N = 10) were 0.3–0.4 ng/mL and 1.0–1.3 ng/mL, respectively. In addition, the average recoveries at three spiked levels (5, 10 and 20 ng/mL) varied from 80.0% to 98.7%, with the intra-day and inter-day precisions of 1.4–5.2% and 1.5–8.2%, respectively. The proposed method provided an effective purification performance and gave the enrichment factors of 24.0–29.6. The proposed method was successfully employed for the accurate and sensitive determination of benzodiazepines in urine

Bimetallic PtNi Nanoclusters Supported on Carbon Nanospheres as Catalysts for H₂ Production from Dimethylamineborane Hydrolysis

Although remarkable advances are achieved in the development of novel and high-efficiency catalytic systems for H2 production from the decomposition of dimethylamineborane in neat organic media, there are few available reports on H2 production upon dimethylamineborane hydrolysis. Hence, it is still of high importance to design and develop efficient and highly selective catalysts for H2 production upon dimethylamineborane hydrolysis. Herein, we have first designed and synthesized a series of carbon nanosphere (CNS)-supported PtNi bimetallic nanohybrids (PtNi/CNS), by immobilization of nearly monodispersed PtNi bimetallic nanoparticles at the surface of CNSs, for the highly selective and efficient H2 production from dimethylamineborane hydrolysis. Among them, the optional Pt0.7Ni0.3/CNS nanohybrid exhibits the highest turnover frequency of 16,607 h–1, which exceeded most reported catalytic systems, in the H2 generation from dimethylamineborane hydrolysis at 30 °C under 0.3 M NaOH due to the superior synergistic effect. The activation energy (Ea) of Pt0.7Ni0.3/CNS-catalyzed dimethylamineborane hydrolysis is calculated to be 31.1 kJ/mol. Interestingly, the large kinetic isotope effect of 2.76 with D2O verified that the breaking of a water O–H bond is the rate-controlling step of dimethylamineborane hydrolysis. This work presents a new, efficient, and durable Pt-based nanocatalyst for H2 production from dimethylamineborane hydrolysis

Pt-Based Oxygen Reduction Reaction Catalysts in Proton Exchange Membrane Fuel Cells: Controllable Preparation and Structural Design of Catalytic Layer

Proton exchange membrane fuel cells (PEMFCs) have attracted extensive attention because of their high efficiency, environmental friendliness, and lack of noise pollution. However, PEMFCs still face many difficulties in practical application, such as insufficient power density, high cost, and poor durability. The main reason for these difficulties is the slow oxygen reduction reaction (ORR) on the cathode due to the insufficient stability and catalytic activity of the catalyst. Therefore, it is very important to develop advanced platinum (Pt)-based catalysts to realize low Pt loads and long-term operation of membrane electrode assembly (MEA) modules to improve the performance of PEMFC. At present, the research on PEMFC has mainly been focused on two areas: Pt-based catalysts and the structural design of catalytic layers. This review focused on the latest research progress of the controllable preparation of Pt-based ORR catalysts and structural design of catalytic layers in PEMFC. Firstly, the design principle of advanced Pt-based catalysts was introduced. Secondly, the controllable preparation of catalyst structure, morphology, composition and support, and their influence on catalytic activity of ORR and overall performance of PEMFC, were discussed. Thirdly, the effects of optimizing the structure of the catalytic layer (CL) on the performance of MEA were analyzed. Finally, the challenges and prospects of Pt-based catalysts and catalytic layer design were discussed