A fraction of a 0.05M NaOH solution-soluble polysaccharide, termed AAFRC, was obtained from Auricularia polytricha by protease-assisted aqueous extraction followed by precipitation with ethanol and ...purification with gel filtration chromatography. Analysis by high performance liquid chromatography (HPLC) coupled to a TSK-G5000PWXL column and gel filtration chromatography on Sephacryl S-400HR indicated that AAFRC is homogenous with an average molecular weight (Mw) of about 1.20×106Da. The structure of AAFRC was revealed by chemical methods including Fourier transform infrared (FT-IR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. Results indicated that AAFRC is a glucan consisting 1,3-β-glucan, 1,4-α-glucan, and 1,3-α-glucan backbone with a single 1→)-α-d-glucopyranosyl side-branching unit on every six residues, on average, along the main chain. The growth of transplantable Sarcoma-180 (S180) in mice was also significantly inhibited by AAFRC compared with the model controls (P<0.01), with the inhibitory rate being 43.61%.
► A novel α β-glucan polysaccharide with an average molecular weight of 1.20×106Da. ► The polysaccharide with a single side-branching unit on every six residues. ► The polysaccharide is able to significantly inhibit the growth of Sarcoma-180. ► The structure is useful for revealing mechanisms of food-based therapies.
Subduction of young seafloors straddling mid-ocean ridges (MOR) is an inevitable consequence of plate tectonics. Surprisingly, this process correlates globally with prolonged back-arc extension when ...the MOR is largely trench-parallel. We investigate the underlying mechanism by analyzing the East China Sea Basin (ECSB) whose Cenozoic tectonic history consists of three syn-rift stages with the rift center progressively migrating oceanward. Global geodynamic models satisfying the past subduction history and present-day mantle structures successfully reproduce the lithospheric stress states of the evolving ECSB. We show that segmented removal of the Mesozoic Izanagi slab due to subduction of the young seafloor initiated Paleocene rifting within the western ECSB. Detachment of the former slab facilitated a strong landward mantle wind driven by the large pressure gradient across the slab. The resulting mantle traction pushed the thickened upper plate landward while entraining the young seafloors behind to slowly subduct, a process causing long-lasting Eocene extension of the central ECSB. The waning mantle wind after 30 Ma reduced basal traction and upper plate extension. A final phase of ECSB extension since the late Miocene formed the Okinawa Trough, when the subducting plate became old enough to trigger slab retreat. A similar dynamic scenario is also predicted in other circum-Pacific margins. We conclude that this enduring back-arc extension during MOR subduction represents an important mechanism for continental evolution during the closure of major ocean basins.
•Trench-parallel MOR subduction correlates with back-arc extension globally.•Slab tearing proceeds MOR subduction and generates enduring strong basal traction.•Realistic geodynamic models reproduce extension along major convergent margins.
This paper presents a novel approach that aims to predict better reservoir quality regions from seismic inversion and spatial distribution of key reservoir properties from well logs. The reliable ...estimation of lithology and reservoir parameters at sparsely located wells in the Sawan gas field is still a considerable challenge. This is due to three main reasons: (a) the extreme heterogeneity in the depositional environments, (b) sand-shale intercalations, and (c) repetition of textural changes from fine to coarse sandstone and very coarse sandstone in the reservoir units. In this particular study, machine learning (ML) inversion algorithm was selected to predict the spatial variations of acoustic impedance (AI), porosity, and saturation. While trained in a supervised mode, the support vector machine (SVM) inversion algorithm performed effectively in identifying and mapping individual reservoir properties to delineate and quantify fluid-rich zones. Meanwhile, the Sequential Gaussian Simulation (SGS) and Gaussian Indicator Simulation (GIS) algorithms were employed to determine the spatial variability of lithofacies and porosity from well logs and core analyses data. The calibration of the detailed spatial variations from post-stack seismic inversion using SVM and wireline logs data indicated an appropriate agreement, i.e., variations in AI is related to the variations in reservoir facies and parameters. From the current study, it was concluded that in a highly heterogeneous reservoir, the integration of SVM and GIS algorithms is a reliable approach to achieve the best estimation of the spatial distribution of detailed reservoir characteristics. The results obtained in this study would also be helpful to minimize the uncertainty in drilling, production, and injection in the Sawan gas field of Pakistan as well as other reservoirs worldwide with similar geological settings.
The major polymethoxyflavones in the fruit (ponkan) peels of
Citrus reticulata Blanco cv. ponkan were identified as isosinensetin, sinensetin, nobiletin and tetramethyl-
o-scutellarein by a combined ...separation using high-speed countercurrent chromatography and preparative high performance liquid chromatography, and structure elucidation by electrospray ionisation mass spectrometry (ESI-MS) and
1H and
13C nuclear magnetic resonance (NMR). The antiproliferative activity of the four compounds against four cancer cell lines (A549, HL-60, MCF-7 and HO8910) showed that isosinensetin had a lower IC
50 value for MCF-7 and HO8910 cancer cell lines. Determination of polymethoxyflavones in ponkan peels from different cultivation regions displayed relatively steady contents of the four compounds and a higher content of isosinensetin, which suggested that ponkan peels are excellent sources of functional polymethoxyflavones that may help prevent female cancers, such as ovarian cancer and breast cancer.
Uptake of di-(2-ethylhexyl) phthalate (DEHP) of nine vegetables including potherb mustard, bok choy, celery, spinach, cabbage, leaf of tube, lettuce, garlic, and edible amaranth in plastic film ...greenhouses with different plastic films, film thickness, greenhouse age, and greenhouse height was studied. The results showed that the higher the DEHP content of film, the thicker the film, the lower the height of the greenhouse, and the younger the age of the greenhouse were, the higher the DEHP concentration of vegetables was. The results afford significant information for production of safe vegetables with low level DEHP contamination.
(−)-Epigallocatechin-3-gallate (EGCG) was loaded in heat treated β-lactoglobulin (β-Lg) for the preservation of antioxidant activity. The effects of pH (2.5–7.0), the heating temperature of β-Lg ...(30–85 °C), the molar ratio of β-Lg to EGCG (1:2–1:32), and the β-Lg concentration (1–10 mg/mL) on the properties of β-Lg–EGCG complexes were studied. All four factors significantly influenced the particle size, the ζ-potential, and the entrapment efficiency of EGCG and EGCG loading in β-Lg particles. A stable and clear solution system could be obtained at pH 6.4–7.0. The highest protection of EGCG antioxidant activity was obtained with β-Lg heated at 85 °C and the molar ratio of 1:2 (β-Lg: EGCG). β-Lg–EGCG complexes were found to have the same secondary structure as native β-Lg.
Polysaccharides from a crude extract of
Auricularia polytricha were separated by high-speed countercurrent chromatography (HSCCC). The separation was performed with an aqueous two-phase system of ...PEG1000–K
2HPO
4–KH
2PO
4–H
2O (0.5:1.25:1.25:7.0, w/w). The crude sample (2.0
g) was successfully separated into three polysaccharide components of AAPS-1 (192
mg), AAPS-2 (137
mg), and AAPS-3 (98
mg) with molecular weights of 162, 259, and 483
kDa, respectively. These compounds were tested for growth inhibition of transplanted S180 sarcoma in mice. AAPS-2 had an inhibition rate of 40.4%. The structure of AAPS-2 was elucidated from partial hydrolysis, periodate oxidation, acetylation, methylation analysis, and NMR spectroscopy (
1H,
13C). These results showed AAPS-2 is a polysaccharide with a backbone of (1
→
3)-linked-β-
d-glucopyranosyl and (1
→
3, 6)-linked-β-
d-glucopyranosyl residues in a 2:1 ratio, and has one terminal (1→)-β-
d-glucopyranosyl at the O-6 position of (1→3, 6)-linked-β-
d-glucopyranosyl of the main chain.
The technique of amplitude variation with offset or angle (AVO or AVA) can be used to extract fluid and lithology information from prestack seismic data. Based on three-term AVO equations, three ...elastic parameters can be inverted for by linear AVO inversion. However, many theoretical and numerical studies have demonstrated that by using offset limited data, a three-term AVO inversion may have problems of instability and inaccuracy while inverting for the density term. We have searched for an elastic parameter that contains density information and inverted this parameter in a more stable manner using offset limited data. First, we test the sensitivity of elastic parameters to hydrocarbon reservoirs and select the optimal fluid factor (ρf) that contains density information and has an excellent performance as an inversion parameter used to detect hydrocarbons. Then, we derive approximate PP and PS reflection coefficient equations in terms of the fluid factor. The derived equations allow us to directly estimate the fluid factor of the reservoir. Finally, we apply these equations to synthetic data by employing a joint AVO inversion technique. The results show that the method is stable and unambiguous.
► PP and PS waves joint AVO inversion ► Re-derived PP and PS wave reflected coefficient AVO approximate equations. ► Optimally select the fluid-property which contains density information ► Fluid properties of the reservoir can be estimated in a direct manner. ► The method shows an excellent performance in hydrocarbon detection.
Verifiable and accurate prediction of reservoir pore sizes from well logs in a well with no previous exposure of core data is the desirable outcome for any technique intended to estimate pore size. ...Many methods are based on core and crushed rock samples such as thin section analysis, scanning electron microscope (SEM) and mercury intrusion capillary pressure (MICP) to characterize pore features but these methods are not commonly used because of their high cost. This study introduces a cost-effective approach to establish a relationship between hydraulic flow unit and pore size distribution using routine core analysis data and geophysical well logs. Multi-parameter cluster analysis is used to classify the reservoir rock volume into hydraulic flow unit with similar rock characteristics using reservoir quality index (RQI) and flow zone indicators. Well log and core analysis data were used to identify the hydraulic flow unit in the reservoir interval. The discriminant approach was then applied to the predicted hydraulic flow unit to access the range of pore sizes. The predicted hydraulic flow unit with high porosity and permeability and high RQI revealed a range of pore sizes (macro and mega pores). Comparing the obtained results with high-resolution rock thin section study and available empirical approaches indicated verifiable and satisfactory results. The study can extrapolate the pore size information vertically as well as in the neighboring wells in a quite simple and economical way.
The main difficulty of full waveform inversion (FWI) based on local optimization methods is that it tends to trap in local minima or cycle-skipping associated with inaccurate initial models and ...waveform misfit functions, especially for elastic media. To address this issue, we first discuss the relationship between reverse time migration (RTM) and traditional reflection FWI (RFWI). Then, we present an elastic RFWI (ERFWI) methodology. However, for ERFWI, high nonlinearity still exists in data residuals related misfit function, when true amplitude migration is not adopted. To further mitigate the cycle skipping and avoid the requirements of true amplitude migration, we develop a traveltime-based ERFWI method to update the low-wavenumber components of P- and S-velocity models. The traveltime-based ERFWI only eliminates traveltime residuals along the wave-path of sensitivity kernels to extract the long-wavelength background of the middle and deep parts. Once the traveltime of reflected waves is described correctly, the inversion result using the traveltime-based ERFWI method could be used as a velocity model for prestack depth migration (PSDM) or as an initial model for the conventional FWI to obtain high-resolution velocity model. The final results by combining traveltime-based ERFWI and conventional FWI illustrate that the combined method can obtain an improved result, compared with regular FWI methods.
•Comparing the characteristics of RTM and RFWI to explain the advantage of RFWI•Proposing the ERFWI methodology•Giving the generalized gradient based on weighted cross-correlation objective function•Improving the feasibility of ERFWI using the traveltime gradient operator
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