Natural leather based gamma-ray shielding materials enabled by the coordination of well-dispersed Bi3+/Ba2+ ions and RE2O3 coating

Abstract Gamma rays is widely used in modern science and technology, but it may cause health damage to practitioners. In the present study, natural composites based on leather and high-Z elements (atomic number ≥ 56) were fabricated and used as gamma rays shielding materials. These shielding materials were prepared by coating rare earth nanoparticles (Er2O3 or La2O3) onto the surface of natural leather, which was first impregnated with Bi3+ and Ba2+. Results show that the attenuation efficiency of the prepared Er1.31Bi5.46-NL (1.31 and 5.46 mmol cm−3 loaded elements) with thickness of 3.2 mm was 61.57% for incident rays at 121.78 keV (152Eu) and reached 96.4% in the incident of 59.5 keV (241Am), which is comparable to that of 0.25-mm lead plate (54.54 mmol cm−3). In addition, these natural-leather-based shielding materials exhibited low density (approximately 1/10 of Pb), high strength and wearable behaviors. Graphical abstrac

Environmental Applications of Electromembrane Extraction: A Review

Electromembrane extraction (EME) is a miniaturized extraction technique that has been widely used in recent years for the analysis and removal of pollutants in the environment. It is based on electrokinetic migration across a supported liquid membrane (SLM) under the influence of an external electrical field between two aqueous compartments. Based on the features of the SLM and the electrical field, EME offers quick extraction, effective sample clean-up, and good selectivity, and limits the amount of organic solvent used per sample to a few microliters. In this paper, the basic devices (membrane materials and types of organic solvents) and influencing factors of EME are first introduced, and the applications of EME in the analysis and removal of environmental inorganic ions and organic pollutants are systematically reviewed. An outlook on the future development of EME for environmental applications is also given

Deformation characteristics and engineering effect evaluation of a sandstone bedding excavation high slope treatment project during construction

In order to study the slope deformation law during and after the construction of the sandstone bed-cut high slope support project and the effect of the treatment project, this paper relies on a slope support project in Beijing to analyze the axial force of the anchor cable and the slope during the construction process. The slope displacement is monitored and analyzed, and the results show that the change of the axial force of the anchor cable is mainly divided into the acceleration loss stage, the fluctuation stage and the continuous stable trend stage; the change of the axial force of the anchor cable can well reflect the change of the internal force of the slope; the change of horizontal displacement and vertical settlement can reflect the change law of the deep displacement of the slope and the stability of the slope, has a better support effect. The finite element analysis software was used to simulate the excavation and support process of the sandstone-layered high slope. It was found that with the excavation of the slope, the displacement of the slope developed along the slope angle of the weak sliding surface, and the stability of the slope decreased. The monitoring results and the simulation results are compared and analyzed, and it is found that the change trends of the two are basically the same, which proves that the slope support system can effectively control the deformation of the slope. The research results can provide reference for the design and construction of similar slopes in the future

Prokaryote Distribution Patterns along a Dissolved Oxygen Gradient Section in the Tropical Pacific Ocean

Oceanic oxygen levels are decreasing significantly in response to global climate change; however, the microbial diversity and ecological functional responses to dissolved oxygen (DO) in the open ocean are largely unknown. Here, we present prokaryotic distribution coupled with physical and biogeochemical variables and DO gradients from the surface to near the bottom of a water column along an approximately 12,000-km transect from 13° N to 18° S in the Tropical Pacific Ocean. Nitrate (11.42%), temperature (10.90%), pH (10.91%), silicate (9.34%), phosphate (4.25%), chlorophyll a (3.66%), DO (3.50%), and salinity (3.48%) significantly explained the microbial community variations in the studied area. A distinct microbial community composition broadly corresponding to the water masses formed vertically. Additionally, distinct ecotypes of Thaumarchaeota and Nitrospinae belonging to diverse phylogenetic clades that coincided with specific vertical niches were observed. Moreover, the correlation analysis revealed large-scale natural feedback in which chlorophyll a (organic matter) promoted Thaumarchaeotal biomass at depths that subsequently coupled with Nitrospina, produced and replenished nitrate for phytoplankton productivity at the surface. Low DO also favored Thaumarchaeota growth and fueled nitrate production

Effects of Phosphate Solubilizing Bacteria on the Growth, Photosynthesis, and Nutrient Uptake of <i>Camellia oleifera</i> Abel.

Phosphorus (P) is a necessary nutrient for plant growth and plays an important role in plant metabolisms; however, the majority of P in soil is in insoluble forms. Phosphate solubilizing bacteria (PSB) can convert the insoluble phosphates into plant-available forms and may have the potential for use in sustainable agricultural practices. This study examined the effects of two native PSB, namely Bacillus aryabhattai (JX285) and Pseudomonas auricularis (HN038), and a mixture of both strains (1:1) on the growth of Camellia oleifera Abel. seedlings. The results showed a significant promotion of the growth of C. oleifera plants by three inoculation treatments. All the PSB inoculation treatments could improve the leaf nitrogen (N) and P content and had positive effects on the available N, P, and potassium (K) content of rhizosphere soil. A co-inoculation of the two native PSB strains caused a synergistic effect and achieved the best benefit. In conclusion, B. aryabhattai and P. auricularis could be used as biological agents instead of chemical fertilizers for agricultural production to reduce environmental pollution and increase the yield of tea oil

Atomically thin mesoporous NiCo2O4 grown on holey graphene for enhanced pseudocapacitive energy storage

Pseudocapacitive energy storage\ua0via\ua0Li+\ua0storage at the surface/interface of the electrode is promising for achieving both high energy density and high power density in lithium-ion batteries (LIBs). Thus, we created holey graphene (HG)\ua0via\ua0an etching method, and then\ua0in situ\ua0grew atomically thin mesoporous NiCo2O4\ua0nanosheets on the HG surface, resulting in a NiCo2O4–HG heterostructure. Since both NiCo2O4\ua0and HG possess atomic thickness and porous structures, the as-prepared nanocomposite enables efficient electrolyte diffusion and mass transfer, providing abundant accessible surface atoms for enhanced redox pseudocapacitance. Moreover, the strong coupling effect between NiCo2O4\ua0and graphene produces an ultra-large interfacial area and enhanced electrical conductivity, and subsequently promotes the intercalation pseudocapacitance. Consequently, the NiCo2O4@HG exhibits a high specific capacity of 1103.4 mA h g−1\ua0at 0.2C, ∼88.9% contribution from pseudocapacitance at 1 mV s−1, excellent rate capability, and ultra-long life up to 450 cycles with 931.2 mA h g−1\ua0retention, significantly outperforming previously reported electrodes. This work suggests that the maximum exposure and utilization of the surface/interfacial active sites is vital for the construction of high-performance pseudocapacitive energy storage devices

Atomically thin mesoporous NiCo2O4grown on holey graphene for enhanced pseudocapacitive energy storage

© 2020 The Royal Society of Chemistry. Pseudocapacitive energy storage via Li+ storage at the surface/interface of the electrode is promising for achieving both high energy density and high power density in lithium-ion batteries (LIBs). Thus, we created holey graphene (HG) via an etching method, and then in situ grew atomically thin mesoporous NiCo2O4 nanosheets on the HG surface, resulting in a NiCo2O4-HG heterostructure. Since both NiCo2O4 and HG possess atomic thickness and porous structures, the as-prepared nanocomposite enables efficient electrolyte diffusion and mass transfer, providing abundant accessible surface atoms for enhanced redox pseudocapacitance. Moreover, the strong coupling effect between NiCo2O4 and graphene produces an ultra-large interfacial area and enhanced electrical conductivity, and subsequently promotes the intercalation pseudocapacitance. Consequently, the NiCo2O4@HG exhibits a high specific capacity of 1103.4 mA h g-1 at 0.2C, ∼88.9% contribution from pseudocapacitance at 1 mV s-1, excellent rate capability, and ultra-long life up to 450 cycles with 931.2 mA h g-1 retention, significantly outperforming previously reported electrodes. This work suggests that the maximum exposure and utilization of the surface/interfacial active sites is vital for the construction of high-performance pseudocapacitive energy storage devices

CT imaging changes of corona virus disease 2019(COVID-19): a multi-center study in Southwest China

BACKGROUND:Since the first case of a coronavirus disease 2019 (COVID-19) infection pneumonia was detected in Wuhan, China, a series of confirmed cases of the COVID-19 were found in Southwest China. The aim of this study was to describe the imaging manifestations of hospitalized patients with confirmed COVID-19 infection in southwest China. METHODS:In this retrospective study, data were collected from 131 patients with confirmed coronavirus disease 2019 (COVID-19) from 3 Chinese hospitals. Their common clinical manifestations, as well as characteristics and evolvement features of chest CT images, were analyzed. RESULTS:A total of 100 (76%) patients had a history of close contact with people living in Wuhan, Hubei. The clinical manifestations of COVID-19 included cough, fever. Most of the lesions identified in chest CT images were multiple lesions of bilateral lungs, lesions were more localized in the peripheral lung, 109 (83%) patients had more than two lobes involved, 20 (15%) patients presented with patchy ground glass opacities, patchy ground glass opacities and consolidation of lesions co-existing in 61 (47%) cases. Complications such as pleural thickening, hydrothorax, pericardial effusion, and enlarged mediastinal lymph nodes were detected but only in rare cases. For the follow-up chest CT examinations (91 cases), We found 66 (73%) cases changed very quickly, with an average of 3.5 days, 25 cases (27%) presented absorbed lesions, progression was observed in 41 cases (46%), 25 (27%) cases showed no significant changes. CONCLUSION:Chest CT plays an important role in diagnosing COVID-19. The imaging pattern of multifocal peripheral ground glass or mixed consolidation is highly suspicious of COVID-19, that can quickly change over a short period of time