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The exploitation of solid hydrogen storage materials is an important part of the large-scale application of hydrogen energy. However, Metal agglomeration is one of the main reasons that restrict the hydrogen storage performance of carbon-based hydrogen storage materials. Herein, we develop Ti-decorated boron doped porous graphene as a novel hydrogen storage material based on first-principles calculations. The geometry and electronic structure of Ti-decorated porous graphene with and without boron doped are calculated. Doping boron in porous graphene (PG) can significantly increase the metal-substrate interaction and prevents the formation of Ti-metal clusters. The Ti atom-decorated boron-doped porous graphene (Ti–B/PG) system can stably adsorb sixteen hydrogen molecules with a gravimetric hydrogen uptake of 8.58 wt%. The thermodynamic calculations prove a high usable capacity of the material, at the adsorbing and desorbing conditions of 25 °C, 30 atm and 100 °C, 3 atm. The excellent hydrogen capacity, good recyclability, and desirable desorption capacity of Ti–B/PG make it a very prospective material for hydrogen storage.

The method of MRI (Magnetic Resonance Imaging) image-guided robot for prostate seed implantation has developed rapidly in recent years. During the operation, although the puncture effect guided by MRI is very good, it is difficult for conventional robots driven by motors to work normally in this environment, which reduces the accuracy of seed implantation and affects the treatment effect.First, this paper designs a pneumatic prostate seed implantation robot that is compatible with MRI; the robot is composed of an execution module and an adjustment module, and can complete the positioning and adjustment of the robot's needle entry point, the pose adjustment of the puncture needle and the completion of seed implantation in the MRI space; meanwhile, the statics simulation analysis of its key components is carried out. Then, the kinematics analysis was carried out according to the designed robot structure, and the relationship between the posture of the needle tip and the change of the pneumatic cylinder was obtained; meanwhile, using MATLAB 2020 software, combined with the method of Monte Carlo random number sampling, the simulation analysis of the workspace was carried out. Finally, an experimental prototype is constructed to conduct puncture accuracy experiments, workspace experiments and performance comparison tests in MRI environment.The statics simulation results verify that the key components of the robot designed in this paper can meet the strength requirements of the robot. The simulation results of the workspace meet the requirements of space surgery for prostate seed implantation under the guidance of MRI environment. The puncture accuracy experimented to verify that increasing the puncture speed can improve the seed implantation accuracy, and the puncture deviation of the robot is less than the average deviation of the doctor's actual operation by 6.5 mm. The working space experiment shows that the pitch range is -23.3°~27.8°, the movement range in the X direction is 0~210 mm, the movement range in the Y direction is 0~101 mm, and the lifting range in the Z direction is 0~81 mm, which meets the workspace requirements under MRI. The performance comparison test results in the MRI environment show that the robot is well compatible with MRI instruments.The pneumatic prostate seed implantation robot designed in this paper has a reasonable structure and stable dynamic performance output, and can perform precise surgical operations in the MRI strong magnetic environment. The research work in this paper provides a design reference for the related research on the positioning accuracy of minimally invasive puncture surgery guided by MRI images.

Spirobichroman-based polymers with high gas permeability and selectivity are promising for their applications as membranes in gas separation. In this study, three spirobichroman-based polyimides (PIs; 6FDA-FH, 6FDA-DH, and 6FDA-MH) were synthesised by the polyreaction between diamines containing different substituents (benzene ring, pyridine ring, and methyl group) and 4,4′-(hexafluoroisopropylidene)-diphthalic anhydride (6FDA). The physical properties, gas transport behaviour, d-spacing, dihedral angle of molecules, and fractional free volume of the PIs were investigated through experiments and molecular simulations. The PIs exhibited excellent thermal stability and good solubility in common organic solvents. The gas permeability of the PIs was investigated; the results highlighted the critical role of the substituents in the enhancement of the gas separation performance of polymer membranes. Detailed analysis of the PIs showed that 6FDA-FH exhibits the highest gas permeability. This can be ascribed to the loose packing of the polymer chain owing to the increased dihedral angle between the two planes. However, the methyl substituent in 6FDA-MH disrupts the polymer chain packing rather than changing the dihedral angle between the two planes, thus enhancing the gas permeability of 6FDA-MH. Furthermore, 6FDA-DH exhibited the highest CO2/CH4 selectivity, which is attributed to the CO2 affinity of the polymer containing the pyridine unit.

The buoyancy of Microcystis colonies determines the occurrence and dominance of bloom on the water surface. Besides the cell density regulation and the formation of larger size aggregates, increases in cell volume per colony (Vcell) and the colony's compactness (i.e., volume ratio of cells to the colony, VR) may promote Microcystis colony buoyancy. Yet only a few studies have studied the relationship between the internal structure variation of colonies and their buoyancy, and the co-regulatory role of Vcell and VR of Microcystis colonies in the floating velocity (FV) remains largely unexplored. In the present study, we optimized a method for measuring the compactness of Microcystis colonies based on the linear relationship between total Vcell and chlorophyll a. Different relationships between the VRs and FVs were observed with different colony size and Vcell range groups. Both field and laboratory experiments showed that FV/(D50, median diameter)2 had a significant linear relationship with VR, indicating that the cell density and extracellular polysaccharides were unchanged over a short time period and could be estimated via the slope and intercept of a fitted line. We also constructed a functional relationship between FV, VR, and Vcell and found that high VR and Vcell can promote Microcystis buoyancy. This means that increasing cell compactness or Vcell may be an active regulation strategy for Microcystis colonies to promote buoyancy. Therefore, quantifying the internal structure of Microcystis colonies is strongly recommended for the assessment of Microcystis bloom development and their management. Graphical abstract.

Background Collagen peptides (CP) have been shown to protect against osteoporosis. Yet, its mechanism on anti-osteoporosis remains unclear. Method Cell viability, levels of alkaline phosphatase (ALP), reactive oxygen species (ROS), malondialdehyde (MDA) and superoxide dismutase (SOD) of hydrogen peroxide (H2O2)-induced oxidative stress in Saos-2 cells pretreated with CP were examined. The effect and regulatory of CP on FBXW7-p100-NF-κB axis and the relationship between the molecules were explored by overexpressing FBXW7, silencing p100 or NF-κB in Saos-2 cells. Western blot and RT-PCR were performed to determine the expressions of FBXW7, p100 and NF-κB. Hematoxylin & Eosin (H&E) staining was performed to determine morphological indexes of bone tissues in ovariectomized-induced osteoporosis rats treated with CP. Result CP increased cell viability, ALP and antioxidant activities in H2O2-induced oxidative stress in Saos-2 cells. Results on cell viability, ALP, antioxidant levels, protein and gene expression levels in FBXW7-overexpressed, p100-silenced and NF-κB-silenced Saos-2 cells indicate that FBXW7, p100 and NF-κB are the key regulators and CP treatment modulates FBXW7-p100-NF-κB axis in Saos-2 cells. In addition, pretreatment and treatment with CP in ovariectomized rats improved osteoporosis. Conclusion CP could effectively prevent and alleviate osteoporosis. The protective effect of CP on osteoporosis was achieved in part by inhibiting oxidative damage of osteoblasts and promoting bone formation.

Nitrogen dioxide (NO2) has been attracting a lot of attention because of its toxicity and potential in contaminating land, air, and water. However, research on NO2 release behavior under oxy–fuel c...

Herein, MWCNT-graft-polyimides (MWCNT-g-PIs) were prepared by the in situ grafting method. Strengthening the interfacial interaction between MWCNTs and polyimide chains decreased their interfacial thermal resistance (RC). In contrast to the RC of 10% MWCNT/PIs, the RC of 10% MWCNT-g-PI decreased by 16.7%. Hence, MWCNT-g-PIs possessed higher thermal conductivity than MWCNT/polyimides (MWCNT/PIs). Meanwhile, the Tg values of all the samples (MWCNT/PIs and MWCNT-g-PIs) were greater than 399 °C (by DMA). Compared with MWCNT/PIs, 5% and 10% MWCNT-g-PIs showed enhancement in thermal stability in air. The storage modulus retentions were greater than 63% at 200 °C and 45% at 300 °C. Also, 5% and 10% MWCNT-g-PIs maintained the high tensile strength of pure PI, and the tensile modulus increased up to 2.59 GPa on increasing the loading amount of MWCNTs. This study sheds light on improving the thermal conductivity of polyimides effectively at relatively low loadings.

A temperature-controlled ash deposition probe was applied to collect temporally resolved deposit samples in a 100 kW rated down-fired pilot-scale combustor under two atmospheres: (1) air condition ...

At present, the understanding of the dynamics of denitrifiers at different dissolved oxygen (DO) layers under organic carbon consumption within the surface sediments remains inadequate. In this study, high-throughput sequencing and quantitative PCR targeting nirS gene were used to analyze the denitrifier abundance dynamics, community composition, and structure for aerobic (DO 0.5–6.9 mg/L), hypoxic-anoxic (DO 0–0.5 mg/L), and anoxic (DO 0 mg/L) layers in surface sediments under organic carbon consumption. Based on the analysis of nirS gene abundance, the values of denitrifying bacteria decreased with organic carbon consumption at different DO layers. When the bacterial species abundance at the genus level were compared between the high-carbon and low-carbon sediments, there was significant increase in 6 out of 36, 7 out of 36 and 6 out of 36 genera respectively for the aerobic, hypoxic-anoxic and anoxic layers. On the other hand, 14 out of 36, 9 out of 36 and 15 out of 36 genera showed significant decrease in bacterial species abundance respectively for the aerobic, hypoxic-anoxic and anoxic layers. Additionally, 14 out of 36, 20 out of 36, and 15 out of 36 genera had no change in bacterial species abundance respectively for the aerobic, hypoxic-anoxic, and anoxic layers. This indicates that the carbon utilization ability of different denitrifiers on each DO layers was generally different from each other. Diversity of denitrifying bacteria also presented significant differences in different DO layers between the high- and low-carbon content sediment layers. Moreover, under the high-carbon and low-carbon content, the abundance of nirS gene showed a high peak within the hypoxic-anoxic regions, suggesting that this region might be the main distribution area for the denitrifying bacteria within the surface sediments. Furthermore, community of unique denitrifiers occurred in different DO layers and the adaptive changes of the denitrifier community followed the organic carbon consumption.

Lake Caohai has experienced extensive Microcystis blooms in recent years, and to improve its water quality, the local government carried out a series of water control measures. To better understand the dynamics of both pelagic and benthic Microcystis and their characteristics in Lake Caohai, we conducted a 1-year investigation from December 2015 to December 2016 to gain a seasonal outlook on the distribution and dynamics of cell abundance, colony size and intracellular microcystins (MCs) of Microcystis. The results indicated that the Microcystis bloom occupied primarily the northeastern region and then moved gradually from lakeshore to lake center. The perennial southwesterly winds and the water inflow from northeast to southwest in Lake Caohai determined the spatiotemporal distribution of pelagic Microcystis. Benthic Microcystis was mainly distributed in the northeastern region in summer, occupied the lake center in autumn and then occupied the southeastern region in winter, determined by the sedimentation of pelagic Microcystis and the death of benthic Microcystis. Small colonies (20–60 μm) overwintered more easily in both water column and sediment. The concentrations of intracellular toxin of benthic Microcystis were observed to be significantly higher than those of pelagic Microcystis. This might be because Microcystis synthesized large amount of MCs to acclimate to an unfavorable benthic environment. This knowledge on the dynamics of Microcystis expands our understanding of mechanisms underpinning the formation of Microcystis blooms.

Microcystis is one of the most common bloom-forming cyanobacteria in freshwater ecosystems throughout the world. However, the underlying life history mechanism and distinct temporal dynamics (inter- and intra-annual) of Microcystis populations in different geographical locations and lakes remain unclear but is critical information needed for the development of robust prediction, prevention, and management strategies. Perennial observations indicate that temperature may be the key factor driving differences in the overwintering strategy. This study quantitatively compared the overwintering abilities of Microcystis aeruginosa (Ma) in both the water column and sediments under a gradient of overwintering water temperatures (i.e., 4, 8, and 12 °C) using the death and proliferation rates of Ma. The results show that the dynamics of the Microcystis overwintering strategy were significantly affected by water temperatures. At 4 and 8 °C, Ma mainly overwintered in sediments and disappeared from the water column after exposure to low temperatures for a long duration, although some Microcystis cells can overwinter in the water column for short durations at low temperatures. At 12 °C, most Ma can overwinter in the water column. Rising temperatures promoted the proliferation of pelagic Ma but accelerated the death of benthic Ma. With warmer winter temperatures, pelagic Microcystis might become the primary inoculum sources in the spring. Our study highlights the overwintering strategy flexibility in explaining temporal dynamics differences of Microcystis among in geographical locations and should be considered in the context of global warming.

In the era of big data, more and more users store data in the cloud. Massive amounts of data have brought huge storage costs to cloud storage providers, and data deduplication technology has emerged. In order to protect the confidentiality of user data, user data should be encrypted and stored in the cloud. Therefore, deduplication of encrypted data has become a research hotspot. Cloud storage provides users with data sharing services, and the sharing of encrypted data is another research hotspot. The combination of encrypted data deduplication and sharing will inevitably become a future trend. The current better-performing updateable block-level message-locked encryption (UMLE) deduplication scheme does not support data sharing, and the performance of the encrypted data de-duplication scheme that introduces data sharing is not as good as that of UMLE. This paper introduces the ciphertext policy attribute based encryption (CP-ABE) system sharing mechanism on the basis of UMLE, applies the CP-ABE method to encrypt the master key generated by UMLE, to achieve secure and efficient data deduplication and sharing. In this paper, we propose a permission verification method based on bilinear mapping, and according to the definition of the security model proposed in the security analysis phase, we prove this permission verification method, showing that our scheme is secure. The comparison of theoretical analysis and simulation experiment results shows that this scheme has more complete functions and better performance than existing schemes, and the proposed authorization verification method is also secure.

Out breaks of mass mortalities occurred in Macrobrachium nipponense farms in Jintan county, Jiangsu Province. The bacterial isolates from M. nipponense exhibited the same phenotypic traits and biochemical characteristics, and were identified as Citrobacter freundii according to biochemical characteristics and molecular identification. The infection test revealed that the strain YG2 was pathogenic to M. nipponense, and the half lethal dose (LD

Adsorption mechanism and competitive adsorption of NH3 and As2O3 molecules on CuO (111) surface were investigated via density functional theory (DFT) simulations. The adsorption configuration, adsorption energy, electronic gains/losses, and projected density of states were thoroughly discussed. Results showed that As2O3 molecule was more likely to adsorb on CuO surface than NH3 molecule. For the adsorption of As2O3 on CuO surface, the “Osuf-Osuf bridge” site was the active site with the chemical adsorption energy of −1.39 eV. In the process of NH3 adsorption on CuO surface, N-Cu bond was formed in chemical adsorption, which was mainly attributed to the charge transfer from NH3 molecule to substrate surface. However, no obvious structural change occurred in physisorption. Thermodynamic analysis indicated that physisorption was the primary form for the adsorption of NH3 and As2O3 molecules on CuO surface under the actual SCR condition.

As an economically important crop, tea is widely cultivated in more than 50 countries and has numerous health benefits. Metabolomics has considerable advantages in the analysis of small molecules and has been widely used in tea science. We applied a metabolomic method to evaluate the dynamic changes in metabolites and pathways in the large-, middle- and small-leaf cultivars of Camellia sinensis (L.) Kuntze var. niaowangensis grown in the same area from Yunwu Mountain. The results indicate that flavonoid biosynthesis, stilbenoid, diarylheptanoid and gingerol biosynthesis, citrate cycle (TCA cycle), and propanoate metabolism may play important roles in the differences among cultivars. The levels of tea polyphenols, flavonoids and amino acids may impact the sensory properties of teas of different cultivars. Our results may help to elucidate the mechanism underlying the difference in tea quality and offer references for the breeding of high-quality tea cultivars.

Dynamic control of thioredoxin (Trx) oxidoreductase activity is essential for balancing the need of cells to rapidly respond to oxidative/nitrosative stress and to temporally regulate thiol-based redox signaling. We have previously shown that cytokine stimulation of the respiratory epithelium induces a precipitous decline in cell S-nitrosothiol, which depends upon enhanced Trx activity and proteasome-mediated degradation of Txnip (thioredoxin-interacting protein). We now show that tumor necrosis factor-α–induced Txnip degradation in A549 respiratory epithelial cells is regulated by the extracellular signal-regulated protein kinase (ERK) mitogen-activated protein kinase pathway and that ERK inhibition augments both intracellular reactive oxygen species and S-nitrosothiol. ERK-dependent Txnip ubiquitination and proteasome degradation depended upon phosphorylation of a PXTP motif threonine (Thr(349)) located within the C-terminal α-arrestin domain and proximal to a previously characterized E3 ubiquitin ligase–binding site. Collectively, these findings demonstrate the ERK mitogen-activated protein kinase pathway to be integrally involved in regulating Trx oxidoreductase activity and that the regulation of Txnip lifetime via ERK-dependent phosphorylation is an important mediator of this effect.

The responses of denitrifiers and denitrification ability to dissolved oxygen (DO) concent in different layers of surface lake sediments are still poorly understood. Here, the optimal denitrification condition was constructed based on response surface methodology (RSM) to analyze the denitrification characteristics of surface sediments. The aerobic zone (AEZ), hypoxic zone (HYZ), up-anoxic zone (ANZ-1) and sub-anoxic zone (ANZ-2) were partitioned based on the oxygen contents, and sediments were collected using a customized-designed sub-millimeter scale sampling device. Integrated real-time quantitative PCR, Illumina Miseq-based sequencing and denitrifying enzyme activities analysis revealed that denitrification characteristics varied among different DO layers. Among the four layers, the DNA abundance and RNA expression levels of norB, nirS and nosZ were the highest at the aerobic layer, hypoxic layer and up-axoic layer, respectively. The hypoxia and up-anaerobic layer were the active nitrogen removal layers, since these two layers displayed the highest DNA abundance, RNA expression level and enzyme activities of denitrification functional genes. The abundance of major denitrifying bacteria showed significant differences among layers, with Azoarcus, Pseudogulbenkiania and Rhizobium identified as the main nirS, nirK and nosZ-based denitrifiers. Pearson’s correlation revealed that the response of denitrifiers to environmental factors differed greatly among DO layers. Furthermore, napA showed higher DNA abundance and RNA expression level in the aerobic and hypoxic layers than anaerobic layers, indicating that aerobic denitrifiers might play important roles at these layers. Electronic supplementary material The online version of this article (10.1186/s13568-019-0855-9) contains supplementary material, which is available to authorized users.

Objective: To study on in immunological characteristics of T lymphocyte in peripheral blood from patients with Sjögren's syndrome (SS), provide the theory basis for the further research of Traditional Chinese medicine (TCM) targeted therapy. Methods: T lymphocyte subsets in peripheral blood from SS, RA and normal control groups were tested with various monoclonal antibodies and multicolor flow cytometry. T lymphocyte subsets were tested in peripheral blood from SS patients of different TCM Syndromes. The relationship between T lymphocyte subsets and disease activity was measured by erythrocyte sedimentation rate (SR)and serum IgG. Results: The percentage of CD4+T cells and the ration of CD4+ / CD8+ T cells in peripheral blood from SS patients decreased significantly, and the percentage of CD8+T cells increased than that in control groups (P < 0.05). Compared with patients in inactive period, the percentage of CD4+ T cells in peripheral blood from SS patients in the active stage increased (P > 0.05), the percentage of CD8+T cells decreased (P > 0.05), and the ration of CD4+ / CD8+ T cells increased (P < 0.05). Compared with control groups, the percentage of CD69 expressed on T cells in peripheral blood from SS patients decreased, and the percentage of CD95's expression increased (P < 0.05). The percentage of CD69CD95's expression also increased (P ＞ 0.05). There were no differences among CD4+ T cells, CD8+ T cells and CD4+ / CD8+ in peripheral blood from SS patients of different TCM Syndromes (P > 0.05). CD69 and CD95's expression on SS patients of different TCM Syndromes was no significantly different (P > 0.05). T cell receptor Vβ (TCR Vβ) subfamilies gene in peripheral blood from SS patients and control groups were expressed in all. Compared with control groups, Vβ 5.3, Vβ 13.1, Vβ 12, Vβ 7.2 had significant differences (P < 0.05). Comparison of different TCM Syndromes in SS group: Vβ 13.1 and Vβ 14 were significantly different (P < 0.05). Conclusion: There was dysimmunity on T lymphocyte subsets in peripheral blood of SS patients, which was related to disease activity; apoptosis after activation of autoreactive T cell may be induced by Chinese medicine; TCR Vβ subfamilies of different TCM syndromes were different, which noted that different autoreactive T cells of abnormal activation tended to result in different expression of TCM Different syndromes.

Removing the extensively accumulated cyanobacteria from lake is a straightforward means to tackle cyanobacterial blooms. However, developing removal technology with both high removal efficiency and large treatment capacity remains a great challenge. We developed a shipboard rotary drum filter (RDF) with a 35-mu m screen to remove cyanobacterial blooms at a flow rate of 900 m(3)/h in Lake Dianchi (Kunming, China). Nevertheless, the chlorophyll a (chl.a) concentration of the effluent was approximately 50 mu g/L, which is higher than the control target of 20 mu g/L. In this study, we aimed to improve the performance of RDF on cyanobacterial removal by the utilization of cationic polyacrylamide (CPAM). High molecular weight CPAM with a 30% cationic degree exhibited excellent flocculation effectiveness, with low flocculant doses, large sized flocs, short flocculation time, and high resistance to shear forces. Both the filtration rate and the cyanobacteria removal efficiency of the 35-mu m screen were notably improved by 1 mg/L of CPAM. After being added before the water inlet pump and being agitated by the pump impellers, the CPAM could effectively flocculate cyanobacteria particles at a hydraulic retention time shorter than 20 s. Chl.a concentration and turbidity in the effluents of the shipboard RDF were reduced to lower than 20 mu g/L and 12 NTU, respectively. Thus, a shipboard RDF coupled with CPAM flocculation is a promising approach to the removal of cyanobacterial blooms.

The density functional theory was employed to study the effect mechanism of CO₂ on arsenic adsorption by a carbonaceous surface. Geometry optimization and frequency calculation of each structure were calculated by B3LYP-D3/6-31G(d), and the single-point energy of each structure was obtained by B3LYP-D3/6-311+G(d,p). Results show that, when As and As₂O₃ were absorbed on the carbonaceous surface, the adsorption energies were in the range from −526.96 to −463.17 kJ/mol for As and from −24.19 to −11.09 kJ/mol for As₂O₃. It shows that the carbonaceous surface has a chemical adsorption for As and physical absorption for As₂O₃. In the presence of CO₂, the absorption energies decrease, which shows that CO₂ plays a positive impact on As and As₂O₃ adsorption by the carbonaceous surface. By electrostatic potential analysis, it can be concluded that CO₂ absorbed on the carbonaceous surface enhances active sites and, thus, improves the adsorption capacity of the carbonaceous surface for As and As₂O₃. Results show that electrostatic potential is a reliable tool to analyze the strength and orientation of the adsorption reaction, which can be well-predicted and explained by analyzing the magnitude and positions of extrema on the surface. The calculation results clarify the effect of CO₂ on arsenic adsorption by the carbonaceous surface and provide theoretical foundation for the emission and control of arsenic.

Hierarchical CeO2 octahedrons with average edge lengths of ∼562 nm, ∼353 nm, ∼65 nm, ∼52 nm, ∼46 nm self-assembled from 5 to 8 nm primary nanocrystals were synthesized via a facile hydrothermal route by regulating pH value of the reaction system. A possible formation mechanism was proposed. These hierarchical CeO2 octahedrons exhibited high activities for CO oxidation.