Moderate traumatic brain injury (TBI) in children often happen when there's a sudden blow to the frontal bone, end with long unconscious which can last for hours and progressive cognitive deficits. ...However, with regard to the influences of moderate TBI during children adulthood, injury-induced alterations of locomotive ability, long-term memory performance, and hippocampal electrophysiological firing changes have not yet been fully identified. In this study, lateral fluid percussion (LFP) method was used to fabricate moderate TBI in motor and somatosensory cortex of the 6-weeks-old mice. The motor function, learning and memory function, extracellular CA1 neural spikes were assessed during acute and subacute phase. Moreover, histopathology was performed on day post injury (DPI) 16 to evaluate the effect of TBI on tissue and cell morphological changes in cortical and hippocampal CA1 subregions. After moderate LFP injury, the 6-weeks-old mice showed severe motor deficits at the early stage in acute phase but gradually recovered later during adulthood. At the time points in acute and subacute phase after TBI, novel object recognition (NOR) ability and spatial memory functions were consistently impaired in TBI mice; hippocampal firing frequency and burst probability were hampered. Analysis of the altered burst firing shows a clear hippocampal theta rhythm drop. These electrophysiological impacts were associated with substantially lowered NOR preference as compared to the sham group during adulthood. These results suggest that moderate TBI introduced at motorsenory cortex in 6-weeks-old mice causes obvious motor and cognitive deficits during their adulthood. While the locomotive ability progressively recovers, the cognitive deficits persisted while the mice mature as adult mice. The cognitive deficits may be attributed to the general suppressing of whole neural network, which could be labeled by marked reduction of excitability in hippocampal CA1 subregion.
The shaking table test study on the ultra-large diameter shield tunnel in upper-soft and lower-hard site was rare, due to the limitations of test technology and equipment performance. This study ...performed a series of large-scale shaking table tests and numerical simulations, addressing this deficiency on the seismic response of an ultra-large diameter shield tunnel in upper-soft and lower-hard site. In shaking table tests, a modified method of similitude ratio designing developed in our previous study was adopted, which made it possible to conduct the large-scale test on a shaking table with general loading performance. The test and numerical results meet a good agreement, showing that an evident inflection occurs at the soft-hard interface in the curves of peak acceleration amplification factors versus depth. Furthermore, combining numerical simulations on the upper-soft and lower-hard site, pure soft site and pure hard site, the seismic response differences of the tunnel between upper-soft and lower-hard site and pure soft and hard sites are further revealed. The results demonstrate that the largest relative difference of tunnel strains between upper-soft and lower-hard site and pure soft or hard site always appears at haunch, and the haunch strain of the tunnel in upper-soft and lower-hard site keeps being larger than those in pure soft or hard site regardless of excitations. In addition, the deformation mode of the tunnel in upper-soft and lower-hard site is more like the shape of an avocado, while it presents a typical ellipse in pure soft or hard site.
•Shaking table tests are conducted on the ultra-large diameter shield tunnel in upper-soft and lower-hard site.•The seismic behavior of ultra-large diameter shield tunnel in upper-soft and lower-hard site is investigated.•The differences of tunnel strains between upper-soft and lower-hard site, pure soft site and pure hard site are revealed.•The deformation modes of tunnel in upper-soft and lower-hard site, pure soft site and pure hard site are compared.
Attribute-based encryption mechanism is widely used in outsourcing environment because of its charac-teristics of “one-to-many” communication. However, users attributes often change dynamically. In ...order to solve the problem of attribute revocation in the attribute-based encryption scheme in the outsourcing systems, combined with the attribute-based encryption scheme proposed by Yan et al., a revocable ciphertext-policy attribute-based encryption in data outsourcing systems from lattices is introduced. The scheme uses the LWE (learning with error) problem to construct the encryption and decryption algorithm, which can resist the quantum attack. Tree-access structure is adopted to realize flexible fine-grained access strategy. In addition, with the help of the data outsourcing management server, the attribute key and ciphertext are updated to achieve immediate attribute revocation. The scheme is proven to satisfy the security under the selective attribute and selective plaintext attack. The comparative analysi
A-manifolds and/3-manifolds, introduced by Gray （1978）, are two significant classes of Einstein-like Riemannian manifolds. A Riemannian manifold is Ricci parallel if and only if it is simultaneously ...an A-manifold and a B-manifold. The present paper proves that both focal submanifolds of each isoparametric hypersurface in unit spheres with g = 4 distinct principal curvatures are A-manifolds. As for the focal submanifolds with g = 6, m = 1 or 2, only one is an A-manifold, and neither is a B-manifold.
China is a key region for understanding fire activity and the drivers of its variability under strict fire suppression policies. Here, we present a detailed fire occurrence dataset for China, the ...Wildfire Atlas of China (WFAC; 2005-2018), based on continuous monitoring from multiple satellites and calibrated against field observations. We find that wildfires across China mostly occur in the winter season from January to April and those fire occurrences generally show a decreasing trend after reaching a peak in 2007. Most wildfires (84%) occur in subtropical China, with two distinct clusters in its southwestern and southeastern parts. In southeastern China, wildfires are mainly promoted by low precipitation and high diurnal temperature ranges, the combination of which dries out plant tissue and fuel. In southwestern China, wildfires are mainly promoted by warm conditions that enhance evaporation from litter and dormant plant tissues. We further find a fire occurrence dipole between southwestern and southeastern China that is modulated by the El Niño-Southern Oscillation (ENSO).
Polymer composites with high thermal conductivity have promising applications for the thermal management of modern electronic devices. Here, a novel strategy is proposed to enhance the thermal ...conductivity of epoxy composites by employing a hybrid graphene and boron nitride nanoparticle (GBN). In the GBN, boron nitride nanosheets (BNNSs) tightly adsorb onto the surface of graphene via π-π interactions, and act as bridges for conveying phonons as well as barriers for electrons transporting between adjacent graphene particles. The thermal conductivity and dielectric properties of composites containing GBN are then systematically investigated. The thermal conductivity is significantly enhanced (~140%) in GBN/epoxy composites containing only 5 wt% of GBN. High electrical resistivity (3.05 × 1012 Ω·cm) and low dielectric loss (tanδ < 0.08) are also observed. This study provides important insights into the design and fabrication of highly thermally conductive and electrically insulating composites.
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•Hybrid nanoparticles consisting of graphene and boron nitride nanosheets are prepared by combination of sonication and hydrothermal treatment.•Boron nitride nanosheets act as bridges for phonons conveying as well as barriers for electrons transporting between adjacent graphene particles.•Significant thermal conductivity enhancement is achieved at a low hybrid filler loading.
Severe pollution caused by atmospheric particulate matter (PM) has become a global environmental issue. Samples of atmospheric PM were collected before and during the Chinese Spring Festival in ...Xiamen, a coastal city in Southeast China, to investigate their chemical characteristics, sources, and formation mechanisms. The results indicated that PM2.5 mass concentrations comprised 53.60% and 56.31% of total suspended particulates before and during the Spring Festival, respectively. Due to the halt of factory production and construction and the reduction of vehicle flow during the Spring Festival, the concentrations of organic carbon, elemental carbon and water soluble ions in PM2.5 decreased by 78.56%, 84.19% and 27.53%, respectively, compared with those before the Spring Festival. However, the concentrations of K+, Mg2+, Al, Sr, and Ba increased by 3121.76%, 571.67%, 183.71%, 180.15%, and 137.58%, respectively, resulting from the display of fireworks and firecrackers during the Spring Festival. Analysis of backward air mass trajectory indicated that the concentrations of PM2.5 and its components were dominated by local pollution sources before and during the Spring Festival. The relationships between meteorological conditions and pollutant concentrations showed that the secondary organic aerosol was generated from the heterogeneous reaction before the Spring Festival, and the secondary inorganic aerosol was formed by the photochemical reaction during the Spring Festival.
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•Reduction of traffic flow decreased the PM2.5 during the Spring Festival.•Fireworks and firecrackers caused an adverse effect on the quality of atmosphere.•SOA was generated from the heterogeneous reaction before the Spring Festival.•SNA was formed by photochemical reaction during the Spring Festival.•O3 contributed to the formation of both SOC and SNA.
In present work, the abrasive-free jet polishing (AFJP) of bulk single-crystal KDP was first fulfilled, when using a newly-designed low-viscosity microemulsion as the AFJP fluid. The novel AFJP fluid ...shows a typical water-in-oil structure, in which the water cores uniformly distribute in the BmimPF6 IL, with a particle size of about 20-25 nm. What's more, the AFJP fluid is a controllable and selective non-abrasive jet fluid that the shape of the removal function is regular and smooth, presenting a similar Gaussian function, meanwhile, the dispersion coefficient of the removal rate is only 1.9%. Finally, the surface quality of the bulk single-crystal KDP is further improved by AFJP, meanwhile, the subsurface damage is first obviously mitigated.
The behavior of neutrophils is very important for the resolution of inflammation and tissue repair. People have used advanced imaging techniques to observe the phenomenon of neutrophils leaving the ...injured or inflammatory site and migrating back into blood vessels in transgenic zebrafish and mice, which is called neutrophil reverse migration. Numerous studies have shown that neutrophil reverse migration is a double-edged sword. On the one hand, neutrophil reverse migration can promote the resolution of local inflammation by accelerating the clearance of neutrophils from local wounds. On the other hand, neutrophils re-enter the circulatory system may lead to the spread of systemic inflammation. Therefore, accurate regulation of neutrophil reverse migration is of great significance for the treatment of various neutrophil- mediated diseases. However, the mechanism of neutrophil reverse migration and its relationship with inflammation resolution is unknown. In this review, we reviewed the relevant knowledge of neutrophil reverse migration to elucidate the potential mechanisms and factors influencing reverse migration and its impact on inflammation in different disease processes.
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