327 research outputs found
Sea surface salinity observed from the HY-2A satellite
Motivated by the shortcomings of radio frequency interferences (RFI) associated with the spaceborne L-band radiometers near the Northwest Pacific and previous study near the Amazon plume, this study presents a sea surface salinity (SSS) retrieval algorithm from the microwave radiometer onboard the HY-2A satellite. The SSS signal is improved by differentiating the reflectance between the C and X band. A reflectance calibration method is proposed by using a combination of radiative transfer model (RTM) and the Klein-Swift emissivity model. Evaluations of the retrieved SSS from the HY-2A satellite indicate that the root mean square error (RMSE) is about 0.35 psu on 0.5 degree grid spacing and monthly time scale which is comparable to the accuracy of SMOS and Aquarius-SAC/D satellites
Managing Reserve Deliverability Risk Of Integrated Electricity-heat Systems In Day-ahead Market: A Distributionally Robust Joint Chance Constrained Approach
The integrated electricity and heat system (IEHS) is an emerging demand-side flexible resource for power systems. IEHS operators participating in electricity markets considering their capabilities in reserve provision will face the reserve deliverability risk due to the energy-limited storage nature of heat systems. To address this challenge and increase profitability, a distributionally robust joint chance-constrained mechanism with enhanced quantifications is adopted for the heating system and reserve deployment uncertainties. Detailed pipeline storage representation for thermal networks and integrated demand response are incorporated into this strategic participation model. A two-stage distributionally robust joint chance constrained program is then incorporated to effectively manage the reserve deliverability risk by addressing uncertainties from local distributed energy resources and real-time reserve requests. The L-shaped algorithm is then customized by incorporating bi-linear Benders\u27 decomposition and modified scenario filtering method to efficiently tackle solution challenges for the sophisticated model. Numerical results show the advantages of our approach in virtual thermal storage utilization, risk management, computational performance enhancement and scalability
Impact of Inorganically Bound Sulfur on Late Shale Gas Generation
Nonisothermal,
confined pyrolysis was applied to a mature shale
sample from the Ordovician Salgan Formation in Tarim Basin, northwest
China. Experiments were conducted using gold-tubes with added water
at a very slow heating rate (2 °C/h) and end temperatures between
336 and 600 °C. To investigate the influence of inorganically
bound sulfur on the generation of gases and to consider the geological
occurrence of sulfur-containing minerals, such as prevalent pyrite
in shales, the experiments were carried out with and without admixtures
of MgSO<sub>4</sub>, CaSO<sub>4</sub>, and pyrite. High amounts of
methane along with lower amounts of wet gases were formed from highly
mature shale without minerals added, demonstrating a huge late gas
generation potential at post peak-oil window maturities. In the experiments
with added sulfates and pyrite, all organic gases were consumed in
varying proportions, resulting in different chemical and stable carbon
isotopic compositions. Pyrite treatment affects wet gas (C<sub>2</sub>–C<sub>5</sub>) evolution directly, but it affects methane
(C<sub>1</sub>) evolution indirectly. In contrast, sulfate treatments
affect C<sub>1</sub>–C<sub>5</sub> evolution directly. The
cumulative yield ratio of CO<sub>2</sub>/H<sub>2</sub>S indicates
that pyrite impacts on the hydrocarbon gas generation through low
valence sulfur such as S<sup>0</sup> or others, which are associated
with H<sub>2</sub>S generation. In the pyrite series, the smooth increase
in ethane yield at temperatures exceeding 504 °C, together with
a concomitant stable carbon isotope reversal, demonstrates a new origin
for ethane at high temperatures. The isotopic reversal may come from
reactions between water and solid kerogen/coke/pyrobitumen. Isotopic
reversal of ethane occurs only in the control and pyrite series but
not in the sulfate treatments. This provides evidence that anoxic
conditions are required. Thus, one can expect to encounter isotopic
reversals in high maturity, unconventional gas shale environments
in the presence of pyrite
Formulation and characterization of a novel, photoinitiated small intestinal sub-mucosal wound-healing hydrogel
Purpose: To design and characterize a novel 3-D photo-initiated small intestinal sub-mucosal (SIS) hydrogel for use as a scaffold.Methods: Two concentrations of hydrogel were used: 10 mg/mL SIS gel (designated as 1 % hydrogel) and 20 mg/mL SIS gel (designated as 2 % hydrogel). Cross-sections of the hydrogels were examined by scanning electron microscope. In vitro cell culture was carried out on the hydrogels, and cell count was obtained on each hydrogel at different time points. In addition, hematoxylin-eosin (H&E) staining was used to assess in vivo biodegradability of the gels, as well as tissue regeneration.Results: The 1 % hydrogel possessed a larger pore size (143 ± 22 μm) than the 2 % hydrogel (113 ± 17 μm) and showed significantly higher biodegradation rate (22.79 ± 2.47 % of gel left on day 5) than 2% hydrogel (35.37 ± 4.51 % of gel left on day 5) (p < 0.05). However, results from cell culture showed that the 2 % hydrogel had better biocompatibility than 1 % hydrogel. In vivo data revealed that the gels supported cell growth (cell count on days 3 and 5 were 48.33 ± 17.61 and 105.67 ± 21.36, respectively).Conclusion: These results suggest that SIS hydrogels have a high potential for application in tissue regeneration.Keywords: Extracellular matrix, Small intestinal sub-mucosa, Hydrogel, Wound healin
A new fluorescent chemosensor for highly selective and sensitive detection of inorganic phosphate (Pi) in aqueous solution and living cells
In this work, a new fluorescence chemosensor, FP-Fe3+ was developed for the detection of Pi in aqueous solution and living cells. The unique ligand, FP displayed a high affinity to Fe3+ (Ka = 1.40 × 106 M-1) in the presence of other competing cations, accompanied with a dramatic fluorescence quenching. The specific interaction of Pi and FP-Fe3+ ensemble led to the liberation of fluorophore, FP, and thus the fluorescence was recovered. The dose-dependent fluorescence enhancement of FP-Fe3+ showed a good linearity with a detection limit of 300 nM for Pi. The extraordinary performance of the present chemosensor, including high sensitivity, selectivity, and good biocompatibility enable the investigation of fluorescent response for Pi in living cells by confocal microscope. Quantitative monitoring of intracellular Pi was achieved by the flow cytometry analysis
Ru Nanoparticles Supported on MIL-101 by Double Solvents Method as High-Performance Catalysts for Catalytic Hydrolysis of Ammonia Borane
Highly dispersed crystalline Ru nanoparticles (NPs) were successfully immobilized inside the pores of MIL-101 by a double solvents method (DSM). HRTEM clearly demonstrated the uniform distribution of the ultrafine Ru NPs throughout the interior cavities of MIL-101. The synthesized Ru@MIL-101 catalyst was also characterized by X-ray diffraction (XRD), N2 adsorption desorption, and ICP-AES. The catalytic test indicated that the Ru NPs supported MIL-101 material exhibited exceedingly high activity and excellent durability for hydrogen generation from the catalytic hydrolysis of amine boranes
Multiple linear epitopes (B-cell, CTL and Th) of JEV expressed in recombinant MVA as multiple epitope vaccine induces a protective immune response
Epitope-based vaccination might play an important role in the protective immunity against Japanese encephalitis virus (JEV) infection. The purpose of the study is to evaluate the immune characteristics of recombinant MVA carrying multi-epitope gene of JEV (rMVA-mep). The synthetic gene containing critical epitopes (B-cell, CTL and Th) of JEV was cloned into the eukaryotic expression vector pGEM-K1L, and the rMVA-mep was prepared. BALB/c mice were immunized with different dosages of purified rMVA-mep and the immune responses were determined in the form of protective response against JEV, antibodies titers (IgG1 and IgG2a), spleen cell lymphocyte proliferation, and the levels of interferon-γ and interleukin-4 cytokines. The results showed that live rMVA-mep elicited strongly immune responses in dose-dependent manner, and the highest level of immune responses was observed from the groups immunized with 107 TCID50 rMVA-mep among the experimental three concentrations. There were almost no difference of cytokines and neutralizing antibody titers among 107 TCID50 rMVA-mep, recombinant ED3 and inactivated JEV vaccine. It was noteworthy that rMVA-mep vaccination potentiates the Th1 and Th2-type immune responses in dose-dependent manner, and was sufficient to protect the mice survival against lethal JEV challenge. These findings demonstrated that rMVA-mep can produce adequate humoral and cellular immune responses, and protection in mice, which suggested that rMVA-mep might be an attractive candidate vaccine for preventing JEV infection
Influence of composite elastic modulus and lateral load pattern on deflection of anti-slide pile head
This paper develops a new method to directly determine the composite elastic modulus of the reinforced concrete cantilever pile rather than adopt theoretical or empirical approaches. On the basis of the theory of material mechanism, the load-deflection equation was deduced to create the relationship between the elastic modulus and the ratio of load-deflection. The numerical modelling tests based on ANSYS separation modelling technology were carried out to determine the composite elastic modulus under different reinforcement ratio, concrete strength grade and distribution pattern of driving force. The results can be used to create the quantitative relationship between the composite elastic modulus and reinforcement ratio as well as concrete strength grade. Comparison amongst various lateral load pattern were made to show that the deflection of pile head is obviously affected by the lateral load pattern, and the corresponding equations of the deflection of the pile head under different lateral load pattern were proposed, which can reflect the ranking of the great influence on the deflection of the pile head, rectangular, trapezoidal and triangular lateral load pattern in order.
First published online: 24 Aug 201
The Feasibility Study of Megavoltage Computed Tomographic (MVCT) Image for Texture Feature Analysis
Purpose: To determine whether radiomics texture features can be reproducibly obtained from megavoltage computed tomographic (MVCT) images acquired by Helical TomoTherapy (HT) with different imaging conditions.Methods: For each of the 195 textures enrolled, the mean intrapatient difference, which is considered to be the benchmark for reproducibility, was calculated from the MVCT images of 22 patients with early-stage non-small-cell lung cancer. Test–retest MVCT images of an in-house designed phantom were acquired to determine the concordance correlation coefficient (CCC) for these 195 texture features. Features with high reproducibility (CCC > 0.9) in the phantom test–retest set were investigated for sensitivities to different imaging protocols, scatter levels, and motion frequencies using a wood phantom and in-vitro animal tissues.Results: Of the 195 features, 165 (85%) features had CCC > 0.9. For the wood phantom, 124 features were reproducible in two kinds of scatter materials, and further investigations were performed on these features. For animal tissues, 108 features passed the criteria for reproducibility when one layer of scatter was covered, while 106 and 108 features of in-vitro liver and bone passed with two layers of scatter, respectively. Considering the effect of differing acquisition pitch (AcP), 97 features extracted from wood passed, while 103 and 59 features extracted from in-vitro liver and bone passed, respectively. Different reconstruction intervals (RI) had a small effect on the stability of the feature value. When AcP and RI were held consistent without motion, all 124 features calculated from wood passed, and a majority (122 of 124) of the features passed when imaging with a “fine” AcP with different RIs. However, only 55 and 40 features passed with motion frequencies of 20 and 25 beats per minute, respectively.Conclusion: Motion frequency has a significant impact on MVCT texture features, and features from MVCT were more reproducibility in different scatter conditions than those from CBCT. Considering the effects of AcP and RI, the scanning protocols should be kept consistent when MVCT images are used for feature analysis. Some radiomics features from HT MVCT images are reproducible and could be used for creating clinical prediction models in the future
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