The paper mainly discusses the oil and gas engineering techniques based on Digital Earth Platform (DEP), such as exploration, development, gathering and transportation In the process of using oil and gas resources, Digital Earth Platform can promote the engineering with the supported by spatial information. It also improves the scientificity, accuracy, rationality of the oil and gas engineering techniques, greatly reduces cost and increases benefit.
We successfully synthesized four kinds of copolymers with varying molecular weights of poly(lactide-co-glycolide)(PLGA) to yield methoxy-poly(ethylene glycol)-block-poly(lactide-co-glycolide)(mPEG-PLGA) nano carriers: mPEG-PLGA(3k), mPEG-PLGA(9k), mPEG-PLGA(11k) and mPEG-PLGA(16k). An antitumor drug, 10-hydroxycamptothecin(HCPT), was encapsulated into the mPEG-PLGA nanocarrier cores by self-assembly in dialysis. The lower molecular weight nanocarriers degraded more quickly, resulting in mass loss, pH decline, and a rapid HCPT release rate in vitro. The degradation and drug release of the nanocarriers were dependent on the PLGA molecular weight. However, the larger molecular weight nanocarriers could not increase the loading content and encapsulation efficiency. Considering the antitumor effect of these nanocarriers, the mPEG-PLGA(9k) nanocarrier, which had the highest drug loading content[(7.72 +/- 0.57)%] and a relatively high encapsulation efficiency [(22.71 +/- 5.53)%], is an optimum agent for drug delivery.
A combined study of zircon U-Pb dating, Hf isotopes and trace elements has been carried out for granodioritic neosomes of migmatites from the Tianjingping area in northwestern Fujian Province. Zircons are characterized by zoning, higher Th/U ratios (mostly >= 0.1), HREE enrichment, and positive Ce and negative Eu anomalies, and show features similar to magmatic or anatectic zircons. Apparent Pb-206/U-238 ages for the zircons are 447 +/- 2 Ma (95% conf., MSWD = 0.88), corresponding to a Caledonian event. epsilon(Hf)(t) values are -13.3 to -9.7, indicating a crustal source. Two-stage Hf model ages are 1.7 to 1.9 Ga, suggesting that protolith of the migmates was probably formed in the Paleoproterozoic. The granodioritic neosomes have the characteristics of peraluminous calc-alkaline granite, and their REE patterns and trace elements spidergrams show features of middle to upper crustal rocks. Together with previous studies, we conclude that the protolith of the Cathaysia basement in the Tianjingping area was likely formed in the middle-late Paleoproterozoic and experienced partial melting during the Caledonian period. The recognition of Caledonian reworking of the Paleoproterozoic basement in the Cathaysia Block provides a new insight into the tectonic evolution of the Cathaysia Block in the Caledonian period and the interaction between the Cathaysia Block and the Yangtze Block.
The applications of nano-surface chemistry in the field of spectral analysis have attracted growing interest in recent years.In this article,we reviewed the applications of nanomaterials-based chemical reactions for spectral analysis,including the development in plasma-catalysis,surface-enhanced spectroscopy,separation and preconcentration,chemical vapor generation,labeling and signal amplification.Introduction of nano-surface chemistry to spectral analysis not only improves the sensitivity and selectivity,broadens the application range of spectral analysis,but also affords analytical community special characterization tools.
This paper discusses the durability of concrete incorporated with a mineral admixture of siliceous iron tailings that were activated mechanochemically. The mechanochemically activated siliceous iron tailings replaced 10-40% of the cement in the concrete, and tests of the concrete's resistance to permeability, frost, and carbonation were conducted. The test results showed that as 10%, 20%, 30%, and 40% of the cement is replaced, the impermeability of the concrete is superior to that of the control group, and at the cement replacement amounts of 10%, 20%, and 30%, the concrete's impermeability tends to increase with the replacement amount. Furthermore, at the cement replacement amount of 40%, the concrete's impermeability is on a slight decline. As 30% of the cement is replaced, the frost resistance of concrete is better than that of the control concrete, and at the cement replacement amounts of 10%, 20%, and 40%, the frost resistance of the concrete is similar to that of the control group. As 10%, 20%, 30%, and 40% of the cement is replaced, the carbonation resistance of the concrete is inferior to that of the control group, and the carbonation resistance presents a downward trend with the increase in replacement percentage; however, the concrete can still meet the requirements of practical construction works. It follows that when cement is replaced by mechanochemically activated siliceous iron tailings in part, concrete still possesses good durability. (C) 2020 Elsevier Ltd. All rights reserved.
Background: Hyssopus cuspidatus Boriss has been used to treat bronchial asthma for many years in Uighur medicine. JAX2, an ethanol extract from this plant, has effectiveness against bronchial asthma. However, the molecular basis for the anti-inflammatory effects of JAX2 remains unclear. Purpose: This study aimed to evaluate the mechanism of JAX2 against bronchial asthma. Methods: We established an asthma model in rats using ovalbumin (OVA), and an inflammatory model in RAW264.7 cells using lipopolysaccharide (LPS) stimulation. To evaluate the anti-inflammatory effects of JAX2, the concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-4, IL-6, IL-17, eotaxin and immunoglobulin (Ig) E were measured by enzyme-linked immunosorbent assay (ELISA). Cell viability was investigated by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl) 2H-tetrazolium, inner salt (MTS) assay. Further, nitric oxide (NO) and reactive oxygen species (ROS) were determined using Griess reagent and 2,7-dichlorofluorescein diacetate. The phosphorylation of p-extracellular signal-regulated kinase (ERK), p-JunNH2- terminal kinase (JNK), p38 kinases (p38) and p-inhibitor of nuclear factor kappa-B kinase (IKK), and nuclear translocation of p-p65 kinases (p-p65) were determined by immunofluorescence to uncover the effects of JAX2 on the Mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-kappa B) signaling pathways. Results: After JAX2 administration to rats, Interferon (IFN)-gamma concentrations in BALF increased significantly. Further, the concentrations of TNF-alpha, IL-4, IL-6, IL-17 and eotaxin in BALF, and IgE in serum decreased. JAX2 decreased TNF-alpha, IL-6 and NO in cell supernatant, and reduced ROS intracellularly. Concurrently, IFN-gamma concentrations increased in cell supernatant significantly. In LPS-induced RAW264.7 cells, JAX2 inhibited phosphorylation of p-ERK, p-JNK and p-38 MAPK. The subsequent phosphorylation of p-IKK and nuclear translocation of the p-p65 subunit of NF-kappa B were also suppressed. Conclusion: Based on these findings, we believe that JAX2 has both preventive and treatment effects in bronchial asthma. Furthermore, in the RAW264.7 cell inflammatory model, JAX2 also inhibited NF-kappa B and MAPK signaling pathways.
AIM: To evaluate the effects of luteolin against amyloid beta-peptide 25-35 (A beta(25-35)) on rat cerebral microvascular endothelial cells (CMECs). METHODS: CMECs were isolated from Wistar rats at 3-week-old, and randomly divided into 5 groups including control group, A beta(25-35) group, 0.1, 1.0, and 10.0 mu mol.L-1 luteolin groups. Cell viability was determined with MTS assay. Intracelluar ROS level and SOD activity were monitored by DCFH-DA and SOD inhibition assay, respectively. Transendothelial electrical resistance was measured using an EVOM resistance meter. gamma-Glutamyl transpeptidase and alkaline phosphatase activities were detected using activity assay kits. Levels of TXA(2) and PGI(2) in culture medium were measured as their stable metabolites, TXB2 and 6-keto-PGF(1 alpha), by ELISA. RESULTS: Luteolin attenuated A beta(25-35)-induced toxicity at 0.1, 1.0, and 10 mu mol.L-1, inhibited intracellular ROS generation, and increased SOD activity at 1.0 and 10 mu mol.L-1. Luteolin was also found to preserve CMECs barrier function, involving the alleviation of TEER reduction, the increase of characteristic enzymatic activity, and regulation of TXA(2) and PGI(2) secretion. CONCLUSION: Luteolin had the ability to protect rat CMECs against A beta(25-35)-induced toxicity.
A combined study using LA-ICP-MS U-Pb dating, Hf isotopes, trace elements and the Ti-in-zircon geothermometer was carried out on zircons from the metamorphosed basic-ultrabasic rocks in the metamorphic basement of the Cathaysia Block, southwestern Zhejiang Province. The formation and metamorphic ages of the rocks from the metamorphic basement of the Cathaysia Block were determined based on zircon U-Pb geochronology. The age for the magmatic crystalline zircons from the protolith is about 1.85 Ga. The epsilon (Hf) (t) values of the older zircons were from -7 to -3, with two-stage model Hf ages (T(DM2)(LC)) of about 2.9 to 3.4 Ga, indicating that the source material was derived from anatexis and recycling of the Archean crust. The newly formed metamorphic zircons yielded U-Pb ages of 260-230 Ma. The metamorphic temperature calculated using the Ti-in-zircon geothermometer ranged from 610 to 720 degrees C, consistent with the results from petrographic observations, indicating that the Cathaysia Block experienced an amphibolite facies metamorphism during the Indosinian. Results from this study provided an important timeframe for the tectonic evolution in South China and the Southeast Asia during the Late Permian and Early Triassic times.
We established a novel strategy for the synthesis of reduced graphene oxide(rGO)@TiO2 nanotube hybrids using an 18 W UV-assisted photo-catalytic reduction method for utilization as photo-anode of dye-sensitized solar cells(DSSCs). The photo-conversion efficiency of DSSCs was significantly enhanced after the addition of rGO, and in addition, the photo-anode showed decreased internal resistance. Analysis of rGO@TiO2 hybrids by transmissions scanning electron microscopy(TEM), X-ray diffraction(XRD), Raman spectra, N-2 adsorption and desorption, atomic force microscopy(AFM) and X-ray photoelectron spectroscopy(XPS) demonstrates that the rGO modified TiO2 nanotubes can increase the short-circuit current and the conversion efficiency of dye-sensitized solar cells. The efficiency is improved by almost two folds as much compared to those of the bare TiO2 nanotubes.
Chemical vapor generation(CVG) is an important sample introduction technique,and is widely used for atomic spectrometry for its enhanced sensitivity and selectivity.In the past 30 years,inductively coupled plasma mass spectrometry(ICP-MS) has become a widely used and the most sensitive instrument for(ultra-)trace element determination and elemental speciation.A review of applications of this state-of-the-art coupling of CVG and ICP-MS is presented.Discussion is focused on its applications for both element determination and speciation,including hydride generation,cold vapor generation,photochemical vapor generation,alkylation,and electrochemical vapor generation.In addition,recent studies undertaken isotope dilution calibration in CVG-ICPMS for achieving improved accuracy and precision are summarized,and the future perspectives are discussed.
In this paper, an algorithm for estimating fundamental matrix based on removing the exceptional points is proposed. It uses normalized 8-point algorithm to estimate the initial value of the fundamental matrix, and then refines it by eliminating the exceptional points. Furthermore, the Genetic Algorithm(GA) is used to optimize the initial fundamental matrix by minimizing the Sampson error. Experiment results show that our algorithm is quite correct and reasonable for estimating the fundamental matrix.
Rittmann, B. E.
Sequentially and intimately coupled photolysis with biodegradation were evaluated for their ability to accelerate quinoline-removal and quinoline-mineralization kinetics. UV photolysis sequentially coupled to biodegradation significantly improved biomass-growth kinetics, which could be represented well by the Aiba self-inhibition model: UV photolysis increased the maximum specific growth rate ( max) by 15%, and the inhibition constant ( KSI) doubled. An internal loop photo-biodegradation reactor (ILPBR) was used to realize intimately coupled photolysis with biodegradation. The ILPBR was operated with batch experiments following three protocols: photolysis alone (P), biodegradation alone (B), and intimately coupled photolysis and biodegradation (P&B). For P&B, the maximum quinoline removal rate ( rmax) increased by 9%, KSI increased by 17%, and the half-maximum-rate concentration ( KS) decreased by 55%, compared to B; the composite result was a doubling of the quinoline-biodegradation rate for most of the concentration range tested. The degree of mineralization was increased by both forms of photolysis coupled to biodegradation, and the impact was greater for intimate coupling (18% increase) than sequential coupling (5%). The benefits of UV photolysis were greater with intimate coupling than with sequential coupling due to parallel transformation by biodegradation and photolysis.
The theoretical crystal-morphology of zinc tricarbohydrazide perchlorate (ZnCP) was studied using the morphology simulation software. The growth trends and surface characteristics were calculated using the Bravais-Friedel-Donnay- Harker (BFDH), Growth Morphology, and Equilibrium Morphology methods; these provide theoretical guidance for the choice of crystal-control reagents. On the basis of the simulations, experiments were carried out to study the effects of five different crystal-control reagents, including carboxymethylcellulose (A), polyacrylamide (B), dextrin (C), Tween 40 (D), and Tween 60 (E), in the control of the crystal-morphology of ZnCP. Mixtures of two reagents and higher temperatures were used to further optimize the ZnCP crystals. The results show that ZnCP crystals are well dispersed, and have a large apparent density and regular crystal-morphology under the control of a mixture of reagents A and E in a mass ratio of 1:4 at 80 degrees C.
With the purpose of tracing the variations of the organic matter sources of sediments, a sample column (25.96 m in size) from the Hemudu Area of Hangzhou Bay was put through AMS(14)C dating and biogeochemical analysis. TOC and TN presented similar variation trends, suggesting the same and stable sources of organic matter; the bad correlation between the grain size and TOC content indicated that the organic matter occurrence was neither controlled by the grain size nor the surface absorption of the fine particles, but it may has something to do with the complicated sedimentary hydrodynamic force, the input of organic matter and microbial action. Judging on the basis of C/N ratio and delta C-13(TOC), the organic carbon in sediments was a mixture of terrigenous and marine organic carbon, testifying to the land-sea interaction characteristic of the study area. The indexes experienced abrupt changes at about 6.5 ka BP, when the lighter terrigenous organic carbon made an increased proportion to the heavier marine organic carbon. The phenomenon reflected the enclosure of the lagoon and the reduced exchange interactions with the seawater of open seas.