Multi-GNSS Combined Orbit and Clock Solutions at iGMAS.

Global navigation services from the quad-constellation of GPS, GLONASS, BDS, and Galileo are now available. The international GNSS monitoring and assessment system (iGMAS) aims to evaluate the navigation performance of the current quad systems under a unified framework. In order to assess impact of orbit and clock errors on the positioning accuracy, the user range error (URE) is always taken as a metric by comparison with the precise products. Compared with the solutions from a single analysis center, the combined solutions derived from multiple analysis centers are characterized with robustness and reliability and preferred to be used as references to assess the performance of broadcast ephemerides. In this paper, the combination method of iGMAS orbit and clock products is described, and the performance of the combined solutions is evaluated by various means. There are different internal precisions of the combined orbit and clock for different constellations, which indicates that consistent weights should be assigned for individual constellations and analysis centers included in the combination. For BDS-3, Galileo, and GLONASS combined orbits of iGMAS, the root-mean-square error (RMSE) of 5 cm is achieved by satellite laser ranging (SLR) observations. Meanwhile, the SLR residuals are characterized with a linear pattern with respect to the position of the sun, which indicates that the solar radiation pressure (SRP) model adopted in precise orbit determination needs further improvement. The consistency between combined orbit and clock of quad-constellation is validated by precise point positioning (PPP), and the accuracies of simulated kinematic tests are 1.4, 1.2, and 2.9 cm for east, north, and up components, respectively.

Effects of slight structural distortion on the luminescence performance in (Ca1-x Eux )WO4 luminescent materials.

(Ca1-x Eux )WO4 (x = 0-21 mol%) phosphors were prepared using the classical solid-state reaction method. The influence of Eu3+ ion doping on lattice structure was observed using powder X-ray diffraction and Fourier transform infrared spectroscopy. Furthermore, under this influence, the luminescence properties of all samples were analyzed. The results clearly illustrated that the element europium was successfully incorporated into the CaWO4 lattice with a scheelite structure in the form of a Eu3+ ion, which introduced a slight lattice distortion into the CaWO4 matrix. These lattice distortions had no effect on phase purity, but had regular effects on the intrinsic luminescence of the matrix and the f-f excitation transitions of Eu3+ activators. When the Eu3+ concentration was increased to 21 mol%, a local luminescence centre of [WO4 ]2- groups was detected in the matrix and manifested as the decay curves of [WO4 ]2- groups and luminescence changed from single exponential to double exponential fitting. Furthermore, the excitation transitions of Eu3+ between different energy levels (such as 7 F0 →5 L6 , 7 F0 →5 D2 ) also produced interesting changes. Based on analysis of photoluminescence spectra and the chromaticity coordinates in this study, it could be verified that the nonreversing energy transfer of [WO4 ]2- →Eu3+ was efficient and incomplete.

Molten salt synthesis and luminescence of Dy3+ -doped Y3 Al5 O12 phosphors.

Dy3+ -doped Y3 Al5 O12 phosphors were prepared at a relatively low temperature using molten salt synthesis. The phase of the prepared Dy3+ -doped Y3 Al5 O12 phosphors was confirmed using X-ray powder diffraction. Results indicated that Dy3+ doping did not change the Y3 Al5 O12 phase. Following excitation at 352 nm, emission spectra of the Dy3+ -doped Y3 Al5 O12 phosphors consisted of blue, yellow, and red emission bands. The influence of Dy3+ concentration and excitation wavelength on emission was investigated. The ratio of yellow light to blue light varied with change in Dy3+ doping concentration, due to changes in the structure around Dy3+ . Emission intensities also changed when the excitation wavelength was changed. This variation is luminescence generated a system for tunable white light for Dy3+ -doped Y3 Al5 O12 phosphors.

Theoretical Investigation on the Microscopic Mechanism of Lattice Thermal Conductivity of ZnXP2 (X = Si, Ge, and Sn).

Thermal conductivity is an important physical parameter for the application of nonlinear optical single crystal materials. The underlying science of thermal transport behavior is not well established both experimentally and theoretically. In the present work, we have studied the microscopic picture of lattice thermal conductivity of ZnXP2 (X = Si, Ge, Sn), chalcopyrite ABC2 type infrared optical crystals, by using a harmonic and anharmonic lattice dynamic method and phonon Boltzmann transport equation based on first-principle calculations. With the mass of atom X increased, the phonon frequencies and phonon group velocities of ZnXP2 (X = Si, Ge, Sn) are shown not surprisingly to be decreased. Nevertheless, the phonon lifetime of ZnXP2 is unexpectedly increased, which is the governing mechanism for the increased thermal conductivity as 12.5 W/(m·k), 31.6 W/(m·k), and 35.4 W/(m·k), for ZnSiP2, ZnGeP2, and ZnSnP2, respectively, at 300 K. The contributions of optical phonons (with the frequency below 150 cm-1) to the total thermal conductivity are remarkable, reaching 18%, 31%, and 34% for three compounds, due to the significantly increased phonon lifetime in the frequency range 50-150 cm-1. To explore the physical insights of phonon lifetime and phonon anharmonicity, three-phonon scattering phase space and electronic localization function analysis of the X-P bond are provided. The results show that the covalent nature of X-P bonds is enhanced with the increased mass of atom X = Si, Ge, Sn, which induces the reduction of three-phonon scattering phase space in the frequency range 50-150 cm-1, leading to the enhancement of the phonon lifetime and thermal conductivity of ZnXP2.

The stable oxygen isotope ratio of resin extractable phosphate derived from fresh cattle faeces.

RATIONALE: Phosphorus losses from agriculture pose an environmental threat to watercourses. A new approach using the stable oxygen isotope ratio of oxygen in phosphate (δ18 OPO4 value) may help elucidate some phosphorus sources and cycling. Accurately determined and isotopically distinct source values are essential for this process. The δ18 OPO4 values of animal wastes have, up to now, received little attention. METHODS: Phosphate (PO4 ) was extracted from cattle faeces using anion resins and the contribution of microbial PO4 was assessed. The δ18 OPO4 value of the extracted PO4 was measured by precipitating silver phosphate and subsequent analysis on a thermal conversion elemental analyser at 1400°C, with the resultant carbon monoxide being mixed with a helium carrier gas passed through a gas chromatography (GC) column into a mass spectrometer. Faecal water oxygen isotope ratios (δ18 OH2O values) were determined on a dual-inlet mass spectrometer through a process of headspace carbon dioxide equilibration with water samples. RESULTS: Microbiological results indicated that much of the extracted PO4 was not derived directly from the gut fauna lysed during the extraction of PO4 from the faeces. Assuming that the faecal δ18 OH2O values represented cattle body water, the predicted pyrophosphatase equilibrium δ18 OPO4 (Eδ18 OPO4 ) values ranged between +17.9 and +19.9‰, while using groundwater δ18 OH2O values gave a range of +13.1 to +14.0‰. The faecal δ18 OPO4 values ranged between +13.2 and +15.3‰. CONCLUSIONS: The fresh faecal δ18 OPO4 values were equivalent to those reported elsewhere for agricultural animal slurry. However, they were different from the Eδ18 OPO4 value calculated from the faecal δ18 OH2O value. Our results indicate that slurry PO4 is, in the main, derived from animal faeces although an explanation for the observed value range could not be determined.

Intrinsic sources of high thermal conductivity of CdSiP2 determined by first-principle anharmonic calculations.

CdSiP2 is an outstanding mid-infrared nonlinear optical crystal material with high thermal conductivity. However, the microscopic physics behind its thermal transport behavior is still unclear. In this study, we have investigated the source of the thermal conductivity of CdSiP2 based on anharmonicity lattice dynamics (ALD) and the first-principle calculation. The results are well accordance with the experimental measurement in a wide temperature range. Based on our results, the acoustic phonon lifetime of CdSiP2 is higher than that of the thermoelectric and semiconducting materials reported in previous studies, which is induced by the low lattice anharmonicity demonstrated by CdSiP2. The mode-dependent thermal conductivity is obtained with the contribution of optical phonons being significant (27%) above 300 K; this is mainly due to the high phonon group velocity and relatively long phonon lifetime of low-energy optical phonons (80-200 cm-1). A high lifetime of acoustic phonons and remarkable contribution of low-energy optical phonons can be responsible for the high thermal conductivity of CdSiP2.

Nutrient and Microbiome-Mediated Plant-Soil Feedback in Domesticated and Wild Andropogoneae: Implications for Agroecosystems.

Plants influence the abiotic and biotic environment of the rhizosphere, affecting plant performance through plant-soil feedback (PSF). We compared the strength of nutrient and microbe-mediated PSF and its implications for plant performance in domesticated and wild grasses with a fully crossed greenhouse PSF experiment using four inbred maize genotypes (Zea mays ssp. mays b58, B73-wt, B73-rth3, and HP301), teosinte (Z. mays ssp. parviglumis), and two wild prairie grasses (Andropogon gerardii and Tripsacum dactyloides) to condition soils for three feedback species (maize B73-wt, teosinte, Andropogon gerardii). We found evidence of negative PSF based on growth, phenotypic traits, and foliar nutrient concentrations for maize B73-wt, which grew slower in maize-conditioned soil than prairie grass-conditioned soil. In contrast, teosinte and A. gerardii showed few consistent feedback responses. Both rhizobiome and nutrient-mediated mechanisms were implicated in PSF. Based on 16S rRNA gene amplicon sequencing, the rhizosphere bacterial community composition differed significantly after conditioning by prairie grass and maize plants, and the final soil nutrients were significantly influenced by conditioning, more so than by the feedback plants. These results suggest PSF-mediated soil domestication in agricultural settings can develop quickly and reduce crop productivity mediated by PSF involving changes to both the soil rhizobiomes and nutrient availability.

Zea mays genotype influences microbial and viral rhizobiome community structure.

Plant genotype is recognized to contribute to variations in microbial community structure in the rhizosphere, soil adherent to roots. However, the extent to which the viral community varies has remained poorly understood and has the potential to contribute to variation in soil microbial communities. Here we cultivated replicates of two Zea mays genotypes, parviglumis and B73, in a greenhouse and harvested the rhizobiome (rhizoplane and rhizosphere) to identify the abundance of cells and viruses as well as rhizobiome microbial and viral community using 16S rRNA gene amplicon sequencing and genome resolved metagenomics. Our results demonstrated that viruses exceeded microbial abundance in the rhizobiome of parviglumis and B73 with a significant variation in both the microbial and viral community between the two genotypes. Of the viral contigs identified only 4.5% (n = 7) of total viral contigs were shared between the two genotypes, demonstrating that plants even at the level of genotype can significantly alter the surrounding soil viral community. An auxiliary metabolic gene associated with glycoside hydrolase (GH5) degradation was identified in one viral metagenome-assembled genome (vOTU) identified in the B73 rhizobiome infecting Propionibacteriaceae (Actinobacteriota) further demonstrating the viral contribution in metabolic potential for carbohydrate degradation and carbon cycling in the rhizosphere. This variation demonstrates the potential of plant genotype to contribute to microbial and viral heterogeneity in soil systems and harbors genes capable of contributing to carbon cycling in the rhizosphere.

Inhibitory effect of paeoniflorin on the inflammatory vicious cycle between adipocytes and macrophages.

Obesity is associated with a state of chronic, low-grade inflammation. It is considered that the paracrine loop involving free fatty acid (FFA) and tumor necrosis factor (TNF)α between adipocytes and macrophages establishes an inflammatory vicious cycle that augments the inflammatory changes and insulin resistance in obese adipose tissue. Paeoniflorin (PF), one of the major components of Paeony root, has been shown to have anti-inflammatory effects in vivo. We investigated the effect of PF on the production of FFA and TNFα in the interaction between adipocytes and macrophages. Coculture of 3T3-L1 adipocytes and RAW 264.7 macrophages markedly enhanced the production of TNFα and FFA compared with the control cultures, however, treatment with PF dose-dependently inhibited the production. We further examined the effects of PF on TNFα-stimulated adipocyte lipolysis and on FFA-induced macrophage TNFα expression. PF inhibited TNFα-stimulated adipocyte lipolysis in a dose-dependent manner, which was compatible with suppressed phosphorylation of TNFα-activated ERK1/2 and preserved downregulation of perilipin. Palmitate, one of the most important saturated FFAs, induced macrophage TNFα upexpression, but PF partially attenuated the effect. These results indicate that PF exhibits anti-inflammatory properties by inhibiting the vicious cycle between adipocytes and macrophages. PF may be useful for ameliorating the inflammatory changes in obese adipose tissue.

Biochemical composition and function of subalpine shrubland and meadow soil microbiomes in the Qilian Mountains, Qinghai-Tibetan plateau, China.

Microorganisms participate in the soil biogeochemical cycle. Therefore, investigating variations in microbial biomass, composition, and functions can provide a reference for improving soil ecological quality due to the sensitivity of microorganisms to vegetation coverage changes. However, the differences in soil microorganisms between shrubland and meadow have not been investigated in ecologically vulnerable subalpine areas. This study aimed to investigate the biochemical composition and functions of the soil microbial community under two shrublands and a meadow at high altitudes (3,400-3,550 m). Three sites under two shrublands, Rhododendron thymifolium (RHO) and Potentilla fruticosa (POT), and one meadow dominated by Kobresia myosuroides (MEA), were selected on the southern slope of the Qilian Mountains on the northeastern edge of the Qinghai-Tibetan Plateau, China. Soil physicochemical properties, the microbial community composition expressed by the phospholipid fatty acid (PLFA) biomarker, and enzyme activities were analyzed as well as their relationships. The results showed that water holding capacity and the soil carbon, nitrogen, and potassium content in RHO and POT were higher than those in the MEA. Moreover, the soil active carbon, dissolved organic carbon, total nitrogen, and dissolved total nitrogen content in RHO were higher than those in POT. The abundance of total PLFAs, bacteria, and fungi beneath the shrublands was considerably higher than that in the MEA. The PLFA abundance in RHO was significantly higher than that in POT. The fungal-to-bacterial ratio of RHO and POT was significantly higher than that in the MEA. The activities of ß-glucosidase, cellobiohydrolase, and leucine aminopeptidase were the highest in RHO among the three vegetation types, followed by POT and MEA. The redundancy analysis indicated that the biochemical composition of the soil microorganisms and enzyme activities were driven by total nitrogen, dissolved organic carbon, water holding capacity, and soil organic carbon. Therefore, shrublands, which have higher biomass, can improve soil moisture status, increase soil carbon and nitrogen content (especially active carbon and active nitrogen), and further increase the abundance of total PLFAs, bacteria, and fungi. The increase of microbial biomass indirectly enhances the activity of relevant soil enzymes. The variations in PLFA abundance and enzyme activities can be attributed to shrub species, especially evergreen shrubs, which create more favorable conditions for soil microorganisms. This study provides a theoretical basis for investigating the soil biogeochemical cycle and a scientific basis for soil management and vegetation restoration in the subalpine regions.

A randomized, double-blind, placebo-controlled phase 1 and phase 2 clinical trial to evaluate efficacy and safety of a SARS-CoV-2 vaccine SCoK in adults.

BACKGROUND: To determine an appropriate dose of, and immunization schedule for, a vaccine SCoK against COVID-19 for an efficacy study; herein, we conducted randomized controlled trials to assess the immunogenicity and safety of this vaccine in adults. METHODS: These randomized, double-blind, placebo-controlled phase 1 and 2 trials of vaccine SCoK were conducted in Binhai District, Yan City, Jiangsu Province, China. Younger and older adult participants in phase 1 and 2 trials were sequentially recruited into different groups to be intramuscularly administered 20 or 40 µg vaccine SCoK or placebo. Participants were enrolled into our phase 1 and 2 studies to receive vaccine or placebo. RESULTS: No serious vaccine-related adverse events were observed in either trial. In both trials, local and systemic adverse reactions were absent or mild in most participants. In our phase 1 and 2 studies, the vaccine induced significantly increased neutralizing antibody responses to pseudovirus and live SARS-CoV-2. The vaccine induced significant neutralizing antibody responses to live SARS-CoV-2 on day 14 after the last immunization, with NT50s of 80.45 and 92.46 in participants receiving 20 and 40 µg doses, respectively; the seroconversion rates were 95.83% and 100%. The vaccine SCoK showed a similar safety and immunogenicity profiles in both younger participants and older participants. The vaccine showed better immunogenicity in phase 2 than in phase 1 clinical trial. Additionally, the incidence of adverse reactions decreased significantly in phase 2 clinical trial. The vaccine SCoK was well tolerated and immunogenic.

Solvothermal synthesis and photocatalytic activities of cubic potassium tantalite and cuprum doped potassium tantalite.

KTaO3 and Cu2+ doped KTaO3 were prepared by a solvothermal process. The measurements of XRD, FTIR, XPS, SEM, BET specific surface area, DRS, photoluminescence, photocurrent and electrochemical impedance spectroscopy measurements were carried out to investigate their physical and chemical properties. Especially, the photocatalytic activities of them were revealed by the photocatalysis of MB with irradiation of light in UV-Vis region. The measurements indicate that the Cu2+ doping does not obviously influence the phase and microstructure of KTaO3, but highly changes the optical and electrochemical properties. Cu2+ doped KTaO3 shows higher photocatalytic activity than KTaO3 in the degradation of methylene blue with irradiation of light in UV-Vis region, which results from the enhanced light absorbance, more efficient transfers and separation of photogenerated charge carriers.

Tuning nanocavities of Au@Cu2O yolk-shell nanoparticles for highly selective electroreduction of CO2 to ethanol at low potential.

The electrosynthesis of high-value ethanol from carbon dioxide and carbon monoxide addresses the need for the large-scale storage of renewable electricity and reduction of carbon emissions. However, the electrosynthesis of ethanol by the CO2 reduction reaction (CO2RR) has suffered from low selectivity and energy efficiency. Here, we report a catalyst composed of Au nanoparticles in Cu2O nanocavities (Au@Cu2O) that is very active for CO2 reduction to ethanol through the confinement of the CO intermediate. The architecture shows tandem catalysis mechanisms in which CO2 reduction on Au yolks produces CO filling Cu nanocavities, where a sufficiently high CO concentration due to the confinement effect promotes ethanol formation and then results in an ethanol faradaic efficiency of 52.3% at -0.30 V versus the reversible hydrogen electrode (vs. RHE) via regulating the hollow size of the Cu2O nanocavities. Such a strategy provides a new way of fabricating various tandem catalysts with high selectivity and efficiency for the CO2RR.

Luminescence of Tb3Al5O12 phosphors co-doped with Ce3+/Gd3+ for white light-emitting diodes.

Tb2.96- x Ce0.04GdxAl5O12 phosphors were synthesized through solid-state reactions. The influence of Gd3+ on the luminescence was investigated. Under the excitation at 460 nm, Tb2.96Ce0.04Al5O12 shows the characteristic emission band of Ce3+ with a peak wavelength at about 554 nm. After co-doping Gd3+ into Tb2.96Ce0.04Al5O12, the peak wavelength of the Ce3+ emission band shifts to longer wavelengths, which is induced by the increasing crystal field splitting. However, the Ce3+ emission intensity also decreases because the substitution of Tb3+ with Gd3+ causes lattice deformation and generates numerous structural and chemical defects. By comparing the light parameters of white light-emitting diodes (WLEDs) containing Y2.96Ce0.04Al5O12, Tb2.96Ce0.04Al5O12 and Tb2.81Ce0.04Gd0.15Al5O12 phosphors, we can find that the WLED containing the Tb2.81Ce0.04Gd0.15Al5O12 phosphor generates warmer light than the WLEDs containing Y2.96Ce0.04Al5O12 and Tb2.96Ce0.04Al5O12 phosphors. Moreover, the WLEDs fabricated by integrating a blue LED chip and Ce3+/Gd3+-co-doped Tb3Al5O12 phosphors show outstanding colour stability when driven under different currents.

[Observations of the non-surgical treatment response on diabetic patients with chronic periodontitis].

PURPOSE: To observe the non-surgical treatment response on diabetic patients with chronic periodontitis. METHODS: Moderate to advanced chronic periodontitis was studied in 36 Diabetes Mellitus (DM) patients classified as 20 cases with high and fluctuating blood glucose level (DM-H) and 16 cases with relatively low and stable blood glucose level (DM-L). 28 non-DM patients with chronic periodontitis served as control (Non-DM). Plaque Index (PlI), Gingival Index (GI), Bleeding on Probing (BOP), Probing Depth (PD) and Clinical Attachment Loss (AL) of all patients were recorded at 6 sites on each tooth at the baseline and in the first, the third, the sixth month after oral hygiene instrument (OHI), scaling and root planing. RESULTS: It was found that the short-term effect of non-surgical periodontal procedure had resulted in significant resolution of gingival inflammation and pronounced reduction in pocket depth and gain of attachment loss in all patients. The treatment response was similar in both DM and Non-DM patients with chronic periodontitis. CONCLUSIONS: Non-surgical periodontal treatment allowed for favorable treatment responses in a group of diabetic patients with chronic periodontitis and that their various profiles of blood glucose did not influence the short-term healing response to the treatment.