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COVID-19 has caused major disruptions to agricultural supply chains around the world. Researchers and policy-makers are interested in identifying means to reduce the disruptive effects caused by the pandemic. We investigate the impacts of COVID-19 on the operation of e-commerce stores (in short, e-stores) specialising in agricultural inputs. The difference-in-differences method (DID) is employed to estimate the causal relationship between COVID-19 and online sales of agricultural inputs using data from 54,244 agricultural input e-stores registered in 118 prefecture-level cities across 15 provinces and hosted on two major Chinese e-commerce platforms. The results show that COVID-19 led to a substantial growth in monthly sales of agricultural input e-stores, and this growth of online sales varied across store scales and by types of agricultural inputs. In particular, e-stores selling seeds and seedlings experienced a larger growth in sales than stores selling agricultural machinery and implements, and the mid-and larger-scaled e-stores experienced more growth of sales than micro-and small-scaled e-stores. Further analysis reveals that the growth of online sales of agricultural inputs was driven mainly by an increase in the quantity of customer orders (QCO). The findings of this paper underscore the importance of e-commerce in ensuring the resilience of the agricultural supply chain during the pandemic period. [ABSTRACT FROM AUTHOR]

With the development of information technology, modern test systems require a large number of digital, automated measurement and test equipment. Utilize advanced image measurement technology and digital signal processing technology to digitally transform traditional visual optical instruments, realize efficient and intelligent automatic reading without changing the structure of the instrument, and improve reading accuracy. The upgrade and modification of the visual optical measuring instrument is of great practical significance. Therefore, firstly, a fuzzy edge detection algorithm based on microscope reading images is proposed, which changes the membership function, simplifies the calculation and shortens the processing time. Secondly, the image adaptive method is used to the selection of the segmentation threshold, and the thresholds of various images are gained, so that the segmentation is still more exact. The test results are shown below: the algorithm proposed in this article can hold the low gray edge info of the figure and decrease the reckon time contrast with the traditional PAL-King method. Hence, it can be used in the domain of image handle. [ABSTRACT FROM AUTHOR]

In order to make full use of marine resources, develop marine economy and build a powerful marine country, in recent years, the state has focused on the on-line analysis technology of marine water. In order to solve the problems of rapid change of marine environment and difficulty in the detection and analysis of water quality data, this paper presents an online analysis method of marine water quality data based on large electronic computer after comparing various methods of marine water quality detection in China and abroad. This method uses a variety of marine water quality sensors to collect marine water quality data synthetically, and then uses multi-sensor fusion technology to fuse the collected water quality data. Finally, it combines multisensor D-S evidence theory data fusion technology with computer to analyze water quality data synthetically online. It is concluded that this method can effectively improve the ability of marine pollution early warning and marine ecological environment protection by real-time comprehensive analysis and research of marine water quality data. [ABSTRACT FROM AUTHOR]

In this work, an ultra-wideband coding phase gradient metasurface (CPGM) is proposed for radar cross section (RCS) reduction. The design process is presented in detail, in which eight types of coding elements are proposed firstly by using Pancharatnam-Berry (P-B) phase. The eight types of coding elements have different reflection direction or phase response under the same EM-wave incidence for they can introduce a series of phase gradients with different directions or starting- values under both right-handed and left-handed circular-polarized incidences, so the proposed CPGM composed of these coding elements has excellent performance in RCS reduction. The simulated results show that, compared with a pure metallic plate with the same size, the RCS of the CPGM can be reduced more than 10 dB in the ultra-wide frequency band of 9.2-46.2 GHz under normal incidence with arbitrary polarization, the relative bandwidth is up to 133.6%; moreover, the RCS reduction under oblique incidence with arbitrary polarization can still be kept larger than 9.3 dB in the frequency band of 13.1-42.5 GHz when the incident angle is increased to 45°. Finally, one experiment is carried out, a reasonable agreement exists between the simulated and experimental results. [ABSTRACT FROM AUTHOR]

The functional groups and site interactions on the surfaces of two-dimensional (2D) layered titanium carbide can be tailored to attain some extraordinary physical properties. Herein a 2D alk-MXene (Ti3C2(OH/ONa)xF2-x) material, prepared by chemical exfoliation followed by alkalization intercalation, exhibits preferential Pb(II) sorption behavior when competing cations (Ca-(II)/Mg(II)) coexisted at high levels. Kinetic tests show that the sorption equilibrium is achieved in as short a time as 120 s. Attractively, the alk-MXene presents efficient Pb(II) uptake performance with the applied sorption capacities of 4500 kg water per alk-MXene, and the effluent Pb(II) contents are below the drinking water standard recommended by the World Health Organization (10 μg/L). Experimental and computational studies suggest that the sorption behavior is related to the hydroxyl groups in activated Ti sites, where Pb(II) ion exchange is facilitated by the formation of a hexagonal potential trap. [ABSTRACT FROM AUTHOR]

Long-period stacking ordered (LPSO) phases play an essential role in the development of magnesium alloys because they have a direct effect on mechanical and corrosion properties of the alloys. The LPSO structures are mostly divided to 18R and 14H. However, to date there are no consistent opinions about their degradation properties although both of them can improve mechanical properties. Herein we have successfully obtained two LPSO phases separately in the same Mg-Dy-Zn system and comparatively investigated the effect of different LPSO phases on degradation behavior in 0.9 wt.% NaCl solution. Our results demonstrate that a fine metastable 14H-LPSO phase in grain interior is more effective to improve corrosion resistance due to the presence of a homogeneous oxidation film and rapid film remediation ability. The outstanding corrosion resistant Mg-Dy-Zn based alloys with a metastable 14H-LPSO phase, coupled with low toxicity of alloying elements, are highly desirable in the design of novel Mg-based biomaterials, opening up a new avenue in the area of bio-Mg. [ABSTRACT FROM AUTHOR]

Magnetically aligned bicelles were used as a model membrane to study the orientation and dynamic properties of two cannabinoids (Δ 8-THC and Me-Δ 8-THC) using 31P and 2H NMR. The uniform alignment of the bicelles allowed us to obtain well resolved deuterium spectra from a solution NMR spectrometer. The preferred orientations of Δ 8-THC and Me-Δ 8-THC were calculated on the basis of the measurements of individual quadrupolar splittings. Our results agree with previous experiments using multilamellar membranes as well as with molecular dynamics simulation data described here. In conjunction with our earlier report using small and fast tumbling bicelles, the present work of well aligned bicelles shows that bicelle preparations can provide either pseudoisotropic or anisotropic NMR spectra to study the conformation, orientation, and dynamic properties of ligands in membrane bilayers. Such data are of critical value for understanding the interactions of lipophilic drug molecules with membrane proteins. [ABSTRACT FROM AUTHOR]

Structure−activity relationship studies of classical cannabinoid analogues have established that the C3 aliphatic side chain plays a pivotal role in determining cannabinergic potency. In earlier work, we provided evidence for the presence of subsites within the CB1 and CB2 cannabinoid receptor binding domains that can accommodate bulky conformationally defined substituents at the C3 alkyl side chain pharmacophore of classical cannabinoids. We have now extended this work with the synthesis of a series of Δ 8-THC analogues in which bornyl substituents are introduced at the C3 position. Our results indicate that, for optimal interactions with both CB1 and CB2 receptors, the bornyl substituents need to be within close proximity of the tricyclic core of Δ 8-THC and that the conformational space occupied by the C3 substituents influences CB1/CB2 receptor subtype selectivity. [ABSTRACT FROM AUTHOR]

A number of techniques, including circular dichroism, FTIR, front face fluorescence, and UV absorption spectrophotometries, dynamic light scattering, and DSC, were used to directly measure the colloidal and conformational stability of proteins in highly concentrated solutions. Using bovine serum albumin (BSA), chicken egg white lysozyme, human hemoglobin A0, and bovine fibrinogen as model proteins, the thermal transition temperatures of proteins in dilute and concentrated solutions were compared. At 10 °C, no significant differences in both secondary and tertiary structures were detected for proteins at different concentrations. When temperature was introduced as a variable, however, hemoglobin and fibrinogen demonstrated higher transition midpoints (Tms) in concentrated rather than in dilute solutions (ΔTm ∼ 2–10 °C). In contrast, lysozyme and BSA in concentrated solutions exhibit a lower Tm than in dilute solutions (ΔTm ∼ 2–20 °C). From these studies, it appears that a variety of factors determine the effect of high concentrations on the colloidal and conformational stability of a particular protein. While the prediction of excluded volume theory is that high concentrations should conformationally stabilize proteins, other factors such as pH, kinetics, protein dynamics, and intermolecular charge-charge effects may affect the overall stability of proteins at high concentrations under certain conditions. [ABSTRACT FROM AUTHOR]

The endogenous cannabinoid ligand anandamide is biosynthesized from membrane phospholipid precursors and is believed to reach its sites of action on the CB1 and CB2 receptors through fast lateral diffusion within the cell membrane. To gain a better insight on the stereochemical features of its association with the cell membrane and its interaction with the cannabinoid receptors, we have studied its conformation, location, and dynamic properties in a dipalmitoylphosphatidylcholine multilamellar model membrane bilayer system. By exploiting the bilayer lattice as an internal three- dimensional reference grid, the conformation and location of anandamide were determined by measuring selected inter- and intramolecular distances between strategically introduced isotopic labels using the rotational echo double resonance (REDOR) NMR method. A molecular model was proposed to represent the structural features of our anandamide/lipid system and was subsequently used in calculating the multispin dephasing curves. Our results demonstrate that anandamide adopts an extended conformation within the membrane with its headgroup at the level of the phospholipid polar group and its terminal methyl group near the bilayer center. Parallel static ²H NMR experiments further confirmed these findings and provided evidence that anandamide experiences dynamic properties similar to those of the membrane phospholipids and produces no perturbation to the bilayer. Our results are congruent with a hypothesis that anandamide approaches its binding site by laterally diffusing within one membrane leaflet in an extended conformation and interacts with a hydrophobic groove formed by helices 3 and 6 of CB1, where its terminal carbon is positioned close to a key cysteine residue in helix 6 leading to receptor activation. [ABSTRACT FROM AUTHOR]

Focuses on internal reorganization energy in heterogeneous intermolecular electron transfer. Extension of the Nelsen's method to calculate ... in the return ET reaction of the germinate radical ion pairs (GRIP); Model and method of calculation; Results of study; Discussion on the structure influence of the donor on ....

A simple channel estimator is presented for space time block code (STBC) based orthogonal frequency division multiplexing (OFDM) systems. 3 dB gain over traditional least square estimators is obtained using simple linear process and special pilots design. [ABSTRACT FROM AUTHOR]

High pressure thermal-mechanical treatment (4 GPa) is introduced to improve hardness of a Mg-7 wt. % Li alloy. The improvement in hardness is strongly temperature dependent and the highest hardness occurs in a narrow temperature range around 700 °C. The main reasons for improved hardness are mainly related to the increased phase relative abundance of hcp phase and the formation of superfine {...} compression twins in hcp-Li0.92Mg4.08 phase which effectively inhibits dislocation movement during deformation process. This phase transformation is consistent with the first principles calculations. It demonstrates that high pressure treatment is an effective approach to achieve higher strength Mg-Li based materials [ABSTRACT FROM AUTHOR]

As a powerful tool for studying the microcosm, electron microscopy is becoming more and more widely used and is one of the most important scientific analytical instruments invented in the 20th century. With the rapid development of computer technology and microscopic image technology, microscopic image acquisition and processing technology has been developed and widely used. Traditional human eye observations are easily misjudged by the operator's exhaustion, and images observed by the human eye are not recordable. This paper first introduces the history of the development of the microscope and analyzes the characteristics of the image under the digital microscope. Secondly, some basic theories of image preprocessing and analysis of some new results are discussed. Then the basic theory of edge extraction and the new achievements in edge extraction at home and abroad are discussed. Finally, some algorithms for primitive extraction and feature point extraction are discussed and compared. Combining the above research results into the existing image analysis and processing system can further improve the quality of image 3D visualization and the accuracy of the result data analysis, so as to provide a more objective basis for better expounding the physiological significance revealed. [ABSTRACT FROM AUTHOR]

Objective To determine the accuracy of material-specific images derived from contrast-enhanced dual-energy CT urography (DECTU) in detecting and measuring urinary stones in comparison with that of unenhanced images and its utility in calcified stone differentiation. Methods 105 patients with 202 urinary stones (121 had confirmed composition by infrared spectroscopy) underwent triphasic (unenhanced, portal venous (VP) and excretory phase (EP)) DECTU. Material-specific images were derived in VP and EP with calcium-water, calcium-iodine and CaOxalate_Dihydrate (COD)- Hydroxyapatite (HAP) as basis material pairs. Stone number and size were recorded on unenhanced images and VP and EP material-specific images, where stone densities were also measured. Material densities of calcified stones (pure calcium oxalate [pCaO, n = 34], mixed calcium oxalate [mCaO, n = 14], mixed carbonate phosphate [mCaP, n = 70]) were compared and thresholds for differentiating these stones were determined using receiver operating characteristic analysis. Results All 202 urinary stones were detected on the unenhanced, calcium (water) and calcium (iodine) images in VP. While the detection rate was significantly decreased to 58 and 64% using calcium (water) and calcium (iodine) images in EP, respectively (all p < 0.001). Stone sizes measured on calcium (iodine) images in VP was similar to that of unenhanced images (10.6 vs 10.7 mm, p > 0.05). Significant differences in material densities were found among pCaO, mCaO and mCaP on COD(HAP) images with AUC of 0.72–0.74 for differentiating these stones. Conclusion Material-specific images in VP derived from DECTU allow reliably detecting and measuring urinary tract stones in comparison with unenhanced images and can identify calcified stones with moderate diagnostic performance to provide potential 33% dose reduction. Advances in knowledge Material-specific images, especially the calcium (iodine) images in VP allow for reliable detection of urinary stones. Stone size measurement should be performed on the calcium (iodine) images in VP. Material density measurements on COD-HAP (VP) material decomposition images can be used to differentiate among pure calcium oxalate, mixed calcium oxalate and mixed carbonate phosphate stones with AUC of 0.72–0.74. [ABSTRACT FROM AUTHOR]

The use of polystyrenesulfonate (PSS) thin films in a high-quality passivation scheme involving the suppression of minority carrier recombination at the silicon surface is presented. PSS has been used as a dispersant for aqueous poly-3,4-ethylenedioxythiophene. In this work, PSS is coated as a form of thin film on a Si surface. A millisecond level minority carrier lifetime on a high resistivity Si wafer is obtained. The film thickness, oxygen content, and relative humidity are found to be important factors affecting the passivation quality. While applied to low resistivity silicon wafers, which are widely used for photovoltaic cell fabrication, this scheme yields relatively shorter lifetime, for example, 2.40 ms on n-type and 2.05 ms on p-type wafers with a resistivity of 1-5 Ω·cm. However, these lifetimes are still high enough to obtain high implied open circuit voltages (Voc) of 708mV and 697mV for n-type and p-type wafers, respectively. The formation of oxides at the PSS/Si interface is suggested to be responsible for the passivation mechanism. [ABSTRACT FROM AUTHOR]

The article discusses study that focuses on on the transport mechanism of Ginsenoside Rg1 and the role of sodium-dependent glucose co-transporter 1 in Rg1 uptake regulation after exposure to adrenaline. The study employs monolayers, non-linear regressions analysis, and liquid chromatography. Results reveal that adrenaline enhanced the absorption of Rg1through the regulation of sodium-dependent glucose co-transporter 1.

The article presents a study which evaluates adrenaline (epinephrine) ability to induce ginsenoside Rg1 (Rg1) uptake by Caco-2 cells. It uses Caco-2 cell monolayers to measure the uptake of Rg1. It mentions that adrenergic antagonists such as propranolol and phentolamine were added to the incubation medium to examine the effects of Rg1 uptake. Results show that the adrenaline incubation medium increased the amount of Rg1 uptake through Caco-2 cells.

Objective: To compare 5-year disease-free survival (DFS) and overall survival (OS) rates of laparoscopic radical hysterectomy (LRH) and abdominal radical hysterectomy (ARH) for stage IB1 and tumor size <2 cm with visible or invisible tumors. Methods: We retrospectively compared the oncological outcomes of 1,484 cervical cancer patients with IB1 and tumor size <2 cm on final pathology, who received ARH (n=899) or LRH (n=585) between January 2004 and December 2016. Patients were divided into visible tumor subgroup (ARH: n=668, LRH: n=444) and invisible tumor subgroup (ARH: n=231, LRH: n=141) according to tumor type. Results: LRH and ARH showed similar 5-year DFS and OS rates (93.3% vs. 93.1%, p=0.997; 96.2% vs. 97.5%, p=0.351) in total study population. LRH was not associated with worse 5-year DFS rate (hazard ratio [HR]=0.96; 95% confidence interval [CI]=0.58-1.58; p=0.871) or OS rate (HR=1.37; 95% CI=0.65-2.89; p=0.409) by multivariable analysis. In the visible tumor subgroups, LRH and ARH showed similar 5-year DFS and OS rates (91.9% vs. 91.9%, p=0.933; 95.0% vs. 96.9%, p=0.276), and LRH was not associated with worse 5-year DFS or OS rate (p=0.804, p=0.324). In the invisible tumor subgroups, LRH and ARH also showed similar 5-year DFS and OS rates (97.3% vs. 97.1%, p=0.815; 100% vs. 99.5%, p=0.449), and LRH was not associated with worse 5-year DFS rate (p=0.723). Conclusions: Among patients with stage IB1 and tumor size <2 cm, whether the tumor is visible or not, the oncological outcomes of LRH and ARH among cervical cancer patients are comparable. This suggests that LRH may be suitable for stage IB1 and tumor size <2 cm with visible or invisible tumors. [ABSTRACT FROM AUTHOR]

A hysteresis loop of minority carrier lifetime vs voltage is found in polystyrenesulfonate (PSS)/Si organic-inorganic hybrid heterojunctions, implying an interfacial memory effect. Capacitance-voltage and conductance-voltage hysteresis loops are observed and reveal a memory window. A switchable interface state, which can be controlled by charge transfer based on an electrochemical oxidation/deoxidation process, is suggested to be responsible for this hysteresis effect. We perform first-principle total-energy calculations on the influence of external electric fields and electrons or holes, which are injected into interface states on the adsorption energy of PSS on Si. It is demonstrated that the dependence of the interface adsorption energy difference on the electric field is the origin of this two-state switching. These results offer a concept of organic-inorganic hybrid interface memory being optically or electrically readable, low-cost, and compatible with the flexible organic electronics. [ABSTRACT FROM AUTHOR]

Light-induced degradation has been identified to be a critical issue for most silicon-based solar cell technologies. This study presents an observation of an opposite light-induced enhancement (LIE) effect in photovoltaic performance in poly(3,4-ethylthiophene):polystyrenesulfonate/n-Si organicinorganic hybrid solar cells. The reduced density of interface states under light soaking (LS) is found to be responsible for the LIE of the hybrid solar cells. An increased minor carrier lifetime under LS and a switchable photoluminescence intensity while applying a voltage bias are observed, providing evidence for the underlying physical mechanism [ABSTRACT FROM AUTHOR]

This study explored the effects of reactive nitrogenmetabolites (RNMS) on natural-killer- (NK-) cell-mediated killing of K562 cells and the influence of RNM scavengers, such as tiopronin (TIP), glutamylcysteinylglycine (GSH), and histamine dihydrochloride (DHT), on reversing the suppressing effect of RNM.We administered exogenous and endogenous RNM in the NK + K562 culture system and then added RNM scavengers. The concentrations of RNM, TNF-β and IFN-γ, and NK-cell cytotoxicity (NCC) and the percentage of living NK cells were then examined. We found that both exogenous and endogenous RNM caused the KIR to decrease (P < 0.01); however, RNM scavengers such as TIP and GSH rescued this phenomenon dose dependently. In conclusion, our data suggests that RNM scavengers such as TIP and GSH enhance the antineoplasmic activity of NK cells. [ABSTRACT FROM AUTHOR]

This study explored the effects of reactive nitrogenmetabolites (RNMS) on natural-killer- (NK-) cell-mediated killing of K562 cells and the influence of RNM scavengers, such as tiopronin (TIP), glutamylcysteinylglycine (GSH), and histamine dihydrochloride (DHT), on reversing the suppressing effect of RNM.We administered exogenous and endogenous RNM in the NK + K562 culture system and then added RNM scavengers. The concentrations of RNM, TNF-β and IFN-γ, and NK-cell cytotoxicity (NCC) and the percentage of living NK cells were then examined. We found that both exogenous and endogenous RNM caused the KIR to decrease (P < 0.01); however, RNM scavengers such as TIP and GSH rescued this phenomenon dose dependently. In conclusion, our data suggests that RNM scavengers such as TIP and GSH enhance the antineoplasmic activity of NK cells. [ABSTRACT FROM AUTHOR]

In earlier work we have provided evidence for the presence of a subsite within the CB1 and CB2 cannabinoid receptor binding domains of classical cannabinoids. This putative subsite corresponds to substituents on the C1‘-position of the C3-alkyl side chain, a key pharmacophoric feature in this class of compounds. We have now refined this work through the synthesis of additional C1‘-cycloalkyl compounds using newly developed approaches. Our findings indicate that the C1‘-cyclopropyl and C1‘-cyclopentyl groups are optimal pharmacophores for both receptors while the C1‘-cyclobutyl group interacts optimally with CB1 but not with CB2. The C1‘-cyclohexyl analogs have reduced affinities for both CB1 and CB2. However, these affinities are significantly improved with the introduction of a C2‘−C3‘ cis double bond that modifies the available conformational space within the side chain and allows for a better accommodation of a six-membered ring within the side chain subsite. Our SAR results are highlighted by molecular modeling of key analogs. [ABSTRACT FROM AUTHOR]

Lowering the L10 ordering temperature of FePt films is of great significance for their application as an ultrahigh density magnetic recording medium. In this study, the L10 ordering process of FePt thin films deposited directly on Si substrates has been significantly accelerated by the interface reaction between the thin film and the Si substrate, and thus the thin films show a low L10 ordering temperature of T = 310 °C as compared with those deposited on Si/SiO2 substrates. The accelerated L10 ordering transition is predominantly dependent on the rapid growth of the ordered domains during the interface reaction. The film thickness has an important effect on the interface reaction and thus can be used to tune the L10 ordering process of the FePt films. [ABSTRACT FROM AUTHOR]