Link-State Aware Hybrid Routing in the Terrestrial-Satellite Integrated Network.

In this paper, we study data transmission in the Terrestrial-Satellite Integrated Network (TSIN), where terrestrial networks and satellites are combined together to provide seamless global network services for ground users. However, efficiency of the data transmission is limited by the time-varying inter-satellite link connection and intermittent terrestrial-satellite link connection. Therefore, we propose a link-state aware hybrid routing algorithm, which selects the integrated data transmission path adaptively in this paper. First of all, a space-time topology model is constructed to represent the dynamic link connections in TSIN. Thus, the transmission delay can be analyzed accordingly, and the data transmission problem can then be formulated. To balance the effectiveness and accuracy of searching a hybrid path, we carefully discuss the optimization of space-time topology updating, and propose an inter-satellite link selection algorithm. For the terrestrial-satellite link in hybrid routing, the data transmission problem is transformed into a weighted bipartite graph matching problem and solved with a Kuhn-Munkres-based link selection algorithm. To verify the effectiveness of our proposed routing algorithm, extensive simulations are conducted based on a realistic Hongyun constellation project. Results show that the network performance is improved with respect to data transmission delay, packet loss rate, and throughput.

Dynamic Divide Grouping Non-Orthogonal Multiple Access in Terrestrial-Satellite Integrated Network.

Non-orthogonal multiple access (NOMA) has been extensively studied to improve the performance of the Terrestrial-Satellite Integrated Network (TSIN) on account of the shortage of frequency band resources. In this paper, the terrestrial network and satellite network synergistically provide complete coverage for ground users, and based on the architecture, we first formulate a constrained optimization problem to maximize the sum rate of the TSIN under the limited spectrum resources. As the terrestrial networks and the satellite network will cause interference to each other, we first investigate the capacity performance of the terrestrial networks and the satellite networks separately, in which the optimal power control factor expression is derived. Then, by constructing the relationship model between user elevation angle, beam angle and distance, we develop a dynamic group pairing schemes to ensure the effective pairing of NOMA users. Based on the user pairing, to obtain the optimal resource allocation, a joint optimization algorithm of power allocation, beam channel and base station channel resource is proposed. Finally, simulation results are provided to evaluate the user paring scheme as well as the total system performance, in comparison with the existing works.

Influence of hydrocolloids and natural emulsifier in the physical stability of UHT oat beverage.

This study aimed to improve the physical stability of ultra-high temperature (UHT) oat beverage by adding hydrophilic colloids (guar gum [GG] and xanthan gum [XG]) and a natural emulsifier (soluble soybean polysaccharide [SSPS]). The stability of the oat beverage was characterized by particle size, zeta potential, rheological properties, Fourier-transform infrared (FTIR) spectroscopy, backscattered light intensity (ΔBS), and microstructure. The results indicated that XG reduced the average particle size and size distribution of the beverage, indicating that XG could prevent particle aggregation. GG increases the apparent viscosity of the oat beverage without affecting the zeta potential. When SSPS was added to the oat beverage, it increased the absolute value of the zeta potential and the infrared absorption peak intensity, while the average particle size and backscattered light intensity (ΔBS) decreased, resulting in a more uniform microstructure. The zeta potential reached a maximum value of 32.12 when GG, XG, and SSPS were combined, indicating that the physical stability of the oat beverage was effectively improved when all three were present simultaneously. This study may provide some suggestions for the industrial production of low-viscosity cereal beverages with good stability.

Polyethyleneimine-reinforced Sn/Cu foam dendritic self-supporting catalytic cathode for CO2 reduction to HCOOH.

In this work, a novel catalytic cathode of polyethyleneimine (PEI)-Sn/Cu foam with dendritic structure was prepared by electrodeposition and impregnation. It was used in the electrocatalytic reduction of CO2 to HCOOH, and its performance in this process was evaluated. At -0.97 V vs. RHE, the faradaic efficiency and current density reached 92.3% and 57.1 mA cm-2, respectively, in a 0.5 M KHCO3 electrolyte. The HCOOH production rate reached 890.4 µmol h-1 cm-2, which exceeds those for most reported Sn catalysts. Density functional theory calculations showed that use of Sn/Cu foam is more conducive to HCOOH formation than use of Cu or Sn alone, and *OCHO is the main intermediate in HCOOH formation. The results of OH- adsorption experiments confirmed that the introduction of PEI enhanced the catalytic capacity of the Sn/Cu foam, stabilized CO2·- intermediates, and promoted HCOOH generation. These results will provide an attractive strategy for developing efficient catalysts with excellent activities and stabilities for CO2 electroreduction.

Combining electrokinetic treatment with modified zero-valent iron nanoparticles for rapid and thorough dechlorination of trichloroethene.

In situ injection of nanoscale zero-valent iron (nZVI) slurry is a promising method to treat chlorinated solvents represented by trichloroethylene (TCE) in groundwater. In this study, the effects of sulfidation and emulsification treatment on the performance of nZVI reductive dechlorination of TCE under enhancement by an external electric field were evaluated. The hydrophobic oil film on the surface of sulfidized and emulsified zero-valent iron (S-EZVI) can sequestrate more than one-fifth of the unreacted TCE in the early stage of the experiment (at 5 min). The FeS layer formed on the surface of S-EZVI can facilitate the electron-transfer process and reduce the degree of corrosion of Fe0 with water by 94.0%. Electric-field-enhanced S-EZVI technology can remove more than 93.1% of TCE in the pH range 6.0-9.0, and the performances in overly acid and overly alkali environments both improved. Under the optimal conditions, the TCE removal rate and reaction constant of the applied electric field group reached 96.7% and 1.6 × 10-2 L g-1 min-1, respectively, which were much higher than those of the group without an electric field (53.2% and 3.3 × 10-3 L g-1 min-1) owing to rapid concurrent hydrogenolysis of dichloroethenes and vinyl chloride, or another transformation pathway, such as direct oxidation by the anode. Thereby, this method avoids accumulation of chlorinated intermediates, especially toxic vinyl chloride. This work shows that combination technology has many characteristics that are favorable for field application, and it is expected to provide a new reference and have application value for development of in situ efficient and thorough treatment of TCE-contaminated groundwater.

Graphene-Supported Single Nickel Atom Catalyst for Highly Selective and Efficient Hydrogen Peroxide Production.

Hydrogen peroxide (H2O2) production by electrocatalytic two-electron oxygen reduction shows promise as a replacement for energy-intensive anthraquinone oxidation or H2/O2 direct synthesis. Here, we report on graphene-supported Ni single-atom (SA) electrocatalysts, which are synthesized by a simple surfactant-free reduction process with enhanced electrocatalytic activity and stability. Unlike conventional Ni nanoparticles or alloy catalysts, the well-dispersed Ni-SA sites lack adjacent Ni atoms. This structure promotes H2O2 production by a two-electron oxygen reduction pathway under an alkaline condition (pH = 13). This catalyst exhibited enhanced H2O2 selectivity (>94%) with a considerable mass activity (2.11 A mgNi-1 at 0.60 V vs reversible hydrogen electrode), owing to the presence of oxygen functional groups and isolated Ni sites. Density functional theory calculations provide insights into the role of this catalyst in optimizing the two-electron oxygen reduction reaction pathway with high H2O2 selectivity. This work suggests a new method for controlling reaction pathways in atomically dispersed non-noble catalysts.

Chlorophyll a fluorescence and transcriptome reveal the toxicological effects of bisphenol A on an invasive cyanobacterium, Cylindrospermopsis raciborskii.

Bisphenol A has attracted worldwide attention due to its harmful effects on humans, animals and plants. In this study, the toxicological effects of BPA on Cylindrospermopsis raciborskii were assessed based on chlorophyll a fluorescence and transcriptome analyses. The results showed that the growth of C. raciborskii was significantly inhibited when BPA exceeded 0.1 mg L-1. A marked rise of phase J was observed at a concentration greater than 0.1 mg L-1, while a K phase appeared at 20 mg L-1. The chlorophyll a fluorescence parameters of RC/CS0, F0, φP0, φE0, and ψ0, underwent a significant decline under all treatments of BPA, whereas a significant increase in both VJ and M0 occurred under all concentrations of BPA. Additionally, ABS/RC and DIo/RC markedly increased at 10 mg L-1 and 20 mg L-1. The transcriptome analysis revealed that the genes of photosynthesis, including psbA, psbB, psbC, psbD, apcA, apcB, cpcA, and cpcB, as well as those of chlorophyll and carotenoid biosynthesis, namely hemN, acsF, chlL, chlN, chlP, crtB, pds, were all down-regulated. Moreover, BPA also inhibited the oxidative phosphorylation, glycolysis/gluconeogenesis, citrate cycle (TCA cycle), and fatty acid metabolism in C. raciborskii. Taken together, these results suggest BPA can negatively affect the expression of multiple genes and the vital energy metabolism process to arrest the growth and photosynthesis of C. raciborskii.

Inhibition of matrix metalloproteinases related to metastasis by diosgenyl and pennogenyl saponins.

ETHNOPHARMACOLOGICAL RELEVANCE: Diosgenyl and pennogenyl saponins isolated from Rhizoma Paridis, showed pro-apoptosis and immunoregulation with antitumor activity in cultured cells and animal systems. AIM OF THE STUDY: To evaluate their anti-metastatic mechanism on cancer cells and discuss their structure-activity relationship on anti-tumor effect. MATERIALS AND METHODS: This research used the wound healing and migration assay to detect their anti-invasive effect on B16 melanoma cells. Through the gelatin zymography assay, immunofluorescence analysis and western blot, saponins exhibited different levels of protein expression inhibition of MMP-1, -2, -3, -9 and -14. RESULTS: Through the analysis, diosgenyl and pennogenyl saponins inhibited the metastasis of B16 melanoma cells. Diosgenyl saponins also showed strong suppression of enzyme activity of MMP-2 and -9. Different saponins exhibited different levels of inhibition on MMP expression. CONCLUSIONS: 17-α OH increases the sensitivity of diosgenyl saponins to the membrane-bound protease which can stimulate proMMP-2 activation, but it also decreases the anti-metastatic activity of diosgenyl saponin. Furthermore, their combination might provide a potential therapeutic modality for metastasis.