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To reveal the mechanism of photosynthesis inhibition by infection and the response of the MAPK signaling pathway to pathogen infection, tobacco leaves were inoculated with Pseudomonas syringae pv. tabaci (Pst), and the effects of Pst infection on photosynthesis of tobacco leaves were studied by physiological and proteomic techniques, with a focus on MAPK signaling pathway related proteins. Pst infection was observed to lead to the degradation of chlorophyll (especially Chl b) in tobacco leaves and the down-regulation of light harvesting antenna proteins expression, thus limiting the light harvesting ability. The photosystem II and I (PSII and PSI) activities were also decreased, and Pst infection inhibited the utilization of light and CO2. Proteomic analyses showed that the number of differentially expressed proteins (DEPs) under Pst infection at 3 d were significantly higher than at 1 d, especially the number of down-regulated proteins. The KEGG enrichment of DEPs was mainly enriched in the energy metabolism processes such as photosynthesis antenna proteins and photosynthesis. The down-regulation of chlorophyll a-b binding protein, photosynthetic electron transport related proteins (e.g., PSII and PSI core proteins, the Cytb6/f complex, PC, Fd, FNR), ATP synthase subunits, and key enzymes in the Calvin cycle were the key changes associated with Pst infection that may inhibit tobacco photosynthesis. The effect of Pst infection on the PSII electron acceptor side was significantly greater than that on the PSII donor side. The main factor that decreased the photosynthetic ability of tobacco leaves with Pst infection at 1 d may be the inhibition of photochemical reactions leading to an insufficient supply of ATP, rather than decreased expression of enzymes involved in the Calvin cycle. At 1 d into Pst infection, the PSII regulated energy dissipation yield Y(NPQ) may play a role in preventing photosynthetic inhibition in tobacco leaves, but the long-term Pst infection significantly inhibited Y(NPQ) and the expression of PsbS proteins. Proteins involved in the MAPK signaling pathway were up-regulated, suggesting the MAPK signaling pathway was activated to respond to Pst infection. However, at the late stage of Pst infection (at 3 d), MAPK signaling pathway proteins were degraded, and the defense function of the MAPK signaling pathway in tobacco leaves was damaged.

Intercropping of mulberry (Morus alba L.) and alfalfa (Medicago sativa L.) is a new forestry-grass compound model in China, which can provide high forage yields with high protein. Nitrogen application is one of the important factors determining the production and quality of this system. To elucidate the advantages of intercropping and nitrogen application, we analyzed the changes of physicochemical properties, enzyme activities, and microbial communities in the rhizosphere soil. We used principal components analysis (PCA) and redundancy discriminators analysis to clarify the relationships among treatments and between treatments and environmental factors, respectively. The results showed that nitrogen application significantly increased pH value, available nitrogen content, soil water content (SWC), and urea (URE) activity in rhizosphere soil of monoculture mulberry. In contrast, intercropping and intercropping + N significantly decreased pH and SWC in mulberry treatments. Nitrogen, intercropping and intercropping + N sharply reduced soil organic matter content and SWC in alfalfa treatments. Nitrogen, intercropping, and intercropping + N increased the values of McIntosh diversity (U), Simpson diversity (D), and Shannon–Weaver diversity (H′) in mulberry treatments. However, PCA scatter plots showed clustering of monoculture mulberry with nitrogen (MNE) and intercropping mulberry without nitrogen (M0). Intercropping reduced both H′ and D but nitrogen application showed no effect on diversity of microbial communities in alfalfa. There were obvious differences in using the six types of carbon sources between mulberry and alfalfa treatments. Nitrogen and intercropping increased the numbers of sole carbon substrate in mulberry treatments where the relative use rate exceeded 4%. While the numbers declined in alfalfa with nitrogen and intercropping. RDA indicated that URE was positive when intercropping mulberry was treated with nitrogen, but was negative in monoculture alfalfa treated with nitrogen. Soil pH and SWC were positive with mulberry treatments but were negative with alfalfa treatments. Intercropping with alfalfa benefited mulberry in the absence of nitrogen application. Intercropping with alfalfa and nitrogen application could improve the microbial community function and diversity in rhizosphere soil of mulberry. The microbial community in rhizosphere soil of mulberry and alfalfa is strategically complementary in terms of using carbon sources.

Acid rain, which has negative impacts on the vegetation of ecological systems, is widespread in Northern and Southern China. However, relatively little is known about the effects of acid rain on the growth and yield of economically important tree species in China. To address this issue, we studied the responses of mulberry seedlings to simulated acid rain (SAR) at different pH values. At pH 4.5, SAR induced increased antioxidant activities, total antioxidant capacity, and the accumulation of reactive oxygen species (OFR) relative to controls. However, the growth of the seedlings under SAR treatments at pH 4.5 and pH 5.6 was greater than controls. No significant differences in photosynthesis and chlorophyll a fluorescence quenching parameters were observed between the SAR treatments at pH 4.5 and pH 5.6 and controls. However, the SAR treatment at pH 3.5 resulted in altered leaf surface characteristics and changes to chloroplast ultrastructure, together with an increase in membrane electrical conductivity and an accumulation of OFR and malondialdehyde. In contrast, leaf antioxidant enzyme activities were decreased, together with electron transport parameters and photosynthesis. Taken together, these results show that the effects of acid rain on the growth and leaf physiology of mulberry seedling are dependent on pH. Moreover, mulberry seedlings had a high tolerance to acid rain at pH 4.5.

Circular RNAs (circRNAs) regulate gene expression in eukaryotes and participate in the progression of malignancy. Instead, the function and underlying mechanisms of circ_0000143 in T-cell acute lymphoblastic leukemia (T-ALL) remain unclear. In this study, quantitative real-time polymerase chain reaction (qRT-PCR) was executed to probe circ_0000143 expression in bone marrow samples from T-ALL patients. T-ALL cell lines (MOLT4 and CCRF-CEM) were used to construct cell models. The biological functions of circ_0000143 were studied by CCK-8 assay, Transwell assay, flow cytometry and Western blotting in vitro. Bioinformatics analysis, dual-luciferase reporter gene assay and RIP assay were applied to predict and validate the interaction between circ_0000143 and miR-142-3p, as well as miR-142-3p and cyclic glucocorticoid receptor alpha (GRα). It was revealed that circ_0000143 expression level was significantly reduced in T-ALL samples compared with healthy control. Circ_0000143 overexpression suppressed the viability, migration and invasion, and induced apoptosis of T-ALL cell line. Furthermore, circ_0000143 acted as a molecular sponge to the expression of miR-142-3p. GRα was validated as a downstream target of miR-142-3p, and GRα was positively modulated by circ_0000143. Taken together, these findings reveal that circ_0000143 / miR-142-3p / GRα axis is implicated in the progression of T-ALL , which is expected to become a novel therapeutic target in T-ALL.

The amphiphilic dodecylbenzenesulfonic acid (DBSA) is usually added into wells as an asphaltene precipitation inhibitor. The interfacially active DBSA and asphaltenes will be both adsorbed at the o...

As a bio-based platform chemical, it is desirable to convert levulinic acid (LA) to varieties of value-added biochemicals. n-Butane, mainly from nonrenewable fossil resources, is a basic chemical to produce some important chemicals, such as butadiene and ethylene. In this paper, 95.5% yield of n-butane was obtained from LA in one-step over base-treated Pt/C at around 300 °C in 4 h. The reaction pathway was confirmed to be the hydrodeoxygenation of LA to valeric acid (VA) and then the VA decarboxylation to n-butane by kinetic studies. Base-treated Pt/C had better reactivity due to its improved decarboxylation activity. Detailed characterization of the catalyst revealed that the Pt particle size is the key reason for the activity improvement, and further studies showed that Pt nanoparticles with a size of 2–4 nm showed the highest decarboxylation activity. This is the first report on the direct conversion of LA to n-butane.

In the crude oil production, comb-like octadecyl acrylate (OA) polymers are usually added into the well as flow improver, causing the existence of OA polymers in the produced fluid. OA polymers and...

Paraffins cause many issues during the production and transportation of crude oils. To date, there is abundant research on the rheological properties of crude oils after paraffin crystallization an...

Thioredoxin-like protein CDSP32 (Trx CDSP32), a thioredoxin-like (Trx-like) protein located in the chloroplast, can regulate photosynthesis and the redox state of plants under stress. In order to examine the role of Trx CDSP32 in the photosynthetic apparatus of plants exposed to cadmium (Cd), the effects of Trx CDSP32 on photosynthetic function and photoprotection in tobacco leaves under Cd exposure were studied using a proteomics approach with wild-type (WT) and Trx CDSP32 overexpression (OE) tobacco plants. Cd exposure reduced stomatal conductance, blocked PSII photosynthetic electron transport, and inhibited carbon assimilation. Increased water use efficiency (WUE), cyclic electron flow (CEF) of the proton gradient regulation 5 pathway (PGR5-CEF), and regulated energy dissipation [Y(NPQ)] are important mechanisms of Cd adaptation. However, CEF of the NAD(P)H dehydrogenase pathway (NDH-CEF) was inhibited by Cd exposure. Relative to control conditions, the expression levels of violaxanthin de-epoxidase (VDE) and photosystem II 22 kDa protein (PsbS) in OE leaves were significantly increased under Cd exposure, but those in WT leaves did not change significantly. Moreover, the expression of zeaxanthin epoxidase (ZE) under Cd exposure was significantly higher than that in WT leaves. Thus, Trx CDSP32 increased Y(NPQ) and alleviated PSII photoinhibition under Cd exposure. Trx CDSP32 not only increased PGR5-like protein 1A and 1B expression, but also alleviated the down-regulation of NAD(P)H-quinone oxidoreductase subunits induced by Cd exposure. Thus, Trx CDSP32 promotes CEF in Cd-exposed tobacco leaves. Thus, Trx CDSP32 alleviates the Cd-induced photoinhibition in tobacco leaves by regulating two photoprotective mechanisms: CEF and xanthophyll cycle-dependent energy dissipation.

Soil salinization is a critical factor limiting growth and causing physiological dysfunction in plants. The damage from alkaline salt in most plants is significantly greater than that from neutral salt. However, there is still a lack of research on the action mechanism by which saline alkali stress on plants under the same salt concentration across different pH values. The present study examined the effects of different pH values (7.0, 8.0, 9.0, and 10.0) under the same salt concentration (200 mmolL−1) on photosynthetic function, photoprotective mechanism, nitrogen metabolism, and osmotic regulation in alfalfa (Medicago sativa) leaves, including a transcriptomic analysis of changes in gene expression related to the above metabolic processes. The results showed that low pH saline alkali stress (pH 7.0 and 8.0) promoted chlorophyll synthesis in alfalfa leaves, and non-photochemical quenching (NPQ) and cyclic electron transfer (CEF) were promoted. There was no significant effect on plant growth or photochemical activity. The soluble sugar, proline, and soluble protein contents did not change significantly, and there was no obvious oxidative damage in alfalfa leaves. However, when pH increased to 9.0 and 10.0, KEGG enrichment analysis showed that photosynthesis (map00195) and nitrogen metabolism (map00910) were significantly enriched (P

Photosynthetic induction, a gradual increase in photosynthetic rate on a transition from darkness or low light to high light, has ecological significance, impact on biomass accumulation in fluctuating light and relevance to photoprotection in strong light. However, the experimental quantification of the component electron fluxes in and around both photosystems during induction has been rare. Combining optimized chlorophyll fluorescence, the redox kinetics of P700 [primary electron donor in Photosystem I (PSI)] and membrane inlet mass spectrometry in the absence/presence of inhibitors/mediator, we partially estimated the components of electron fluxes in spinach leaf disks on transition from darkness to 1,000 �mol photons�m−2�s−1 for up to 10 min, obtaining the following findings: (i) the partitioning of energy between both photosystems did not change noticeably; (ii) in Photosystem II (PSII), the combined cyclic electron flow (CEF2) and charge recombination (CR2) to the ground state decreased gradually toward 0 in steady state; (iii) oxygen reduction by electrons from PSII, partly bypassing PSI, was small but measurable; (iv) cyclic electron flow around PSI (CEF1) peaked before becoming somewhat steady; (v) peak magnitudes of some of the electron fluxes, all probably photoprotective, were in the descending order: CEF1 > CEF2 + CR2 > chloroplast O2 uptake; and (vi) the chloroplast NADH dehydrogenase-like complex appeared to aid the antimycin A-sensitive CEF1. The results are important for fine-tuning in silico simulation of in vivo photosynthetic electron transport processes; such simulation is, in turn, necessary to probe partial processes in a complex network of interactions in response to environmental changes.

In this article, poly(aminopropyl/methyl)silsesquioxane (PAMSQ) microspheres with different polarities were first synthesized and characterized. The polarity of the PAMSQ microspheres is progressively enhanced by increasing the aminopropyl molar ratios (1–25 mol%). Then, the effect of PAMSQ microspheres with different polarities on the flowability of the model waxy oils with/without asphaltenes was studied through rheological tests, DSC analyses, microstructure observation and asphaltenes precipitating measurement. The results indicated the PAMSQ microspheres alone could spacially hinder the interactions among the precipitated paraffin crystals, thus slightly improving the flowability of the model waxy oil without asphaltenes (MO-1). The improving ability of PAMSQ microspheres deteriorates with the polarity increasing, and the MO-1 shows the best flowability after adding 200 ppm PAMSQ-1 microsphere (with the aminopropyl molar ratio at 1 mol%). To our surprise, adding PAMSQ microspheres can significantly improve the flow behavior of the model waxy oil with 0.75 wt% asphaltenes (MO-2). Based on the asphaltenes precipitation data, the PAMSQ microspheres could adsorb asphaltenes to form the PAMSQ/asphaltene composite particles in MO-2. The composite particles can play a role of the heterogeneous nucleation templates for paraffin molecules and facilitate the formation of larger and more compact wax floccules, thus enhancing the flowability of MO-2 at low temperatures. The flow improving ability of the PAMSQ microspheres for MO-2 increases with increasing the polarity of the microspheres due to the increased interactions between the microspheres and asphaltenes. The MO-2 exhibits the best flowability after adding 200 ppm PAMSQ-3 microsphere (with aminopropyl molar ratio at 15 mol%). When the polarity of the microspheres is too strong (PMASQ-4 microsphere), however, the microspheres cannot dispersed in waxy oil stably, thus inhibiting the interactions between the microspheres and asphaltenes and deteriorating the flow improving ability of the microspheres for MO-2.

Drought stress led to a decrease in PSII photochemical activity in tobacco leaves and the blockage of electron transfer, especially from QA to QB on PSII acceptor side. In addition, drought stress caused a dramatic increase in H2O2 and MDA contents. However, the overexpression of 2-Cys Prx significantly reduced the H2O2 accumulation in tobacco seedlings and alleviated the degree of oxidative damage under drought stress. It also improved stomatal limitation and net photosynthetic rate of tobacco seedlings and reduced its PSII photoinhibition under drought stress which promoted the ability of PSII electron transfer.

Addition of K+ improves the tolerance of the photosynthetic apparatus to salt stress, but the primary, underlying mechanism is unclear, prompting our study. The main aim of this study was to elucidate the primary mechanism by which supplemental K+ alleviates the effects of salinity stress on photosynthetic parameters in mulberry seedlings. K+ contents in leaves and chloroplasts, plasma-membrane ATPase activity, photosynthetic properties and expression of genes encoding photosynthetic proteins and ion channels/transporters were measured. K+ addition during salt stress improved H+-ATPase activity in plasma-membranes, restored photosynthetic linear and cyclic electron flow, restored the activity of key Photosystem I (PSI) and PSII proteins, and increased dark-adapted PSII photochemical yield Fv/Fm, while reducing non-photochemical quenching. Among the genes encoding ion channels/transporters, that of the Two-Pore-K+ channel in thylakoid membranes (TPK3) was notably responsive to NaCl/K+ treatments: relative to the control (CK) treatment, it decreased slightly in the CK + K treatment, but increased in the NaCl treatment and increased further in the NaCl + K treatment. The above observations are consistent with our hypothesis that K+ supplementation in salt stress restores a high stromal [K+] which, by utilizing TPK3, minimizes a transient, proton diffusion potential that otherwise develops as protons exit the thylakoid lumen through the ATP synthase; thus, rapid charge compensation by K+ movement accelerates both the proton efflux from the lumen and the associated ATP synthesis to enhance carbon assimilation, thereby improving linear as well as cyclic electron flow. The hypothesis pinpoints the primary physicochemical mechanism by which potassium mitigates salt-stress impacts on photosynthesis. It rationalizes both the existence of a K+ channel in thylakoid membranes and the maintenance of a high stromal [K+].

Nitrogen dioxide (NO2) is a common outdoor air pollutant, which has adverse effects on the environment and human health. Herein, NO2 inhibited photosynthesis and antioxidant capacity in plants. Melatonin (Mel) is a neurohormone found in the pineal gland. Exogenous Mel alleviated chlorophyll degradation and increased the expression of key proteins and genes in the process of chlorophyll synthesis in tobacco leaves exposed to NO2. Additionally, the activities of photosystem II (PSII) and photosystem I (PSI) were enhanced. PSII and PSI reaction center proteins and genes were upregulated. Mel pre-treatment enhanced enzyme activities and expression of proteins related to the ascorbic acid–glutathione cycle and thioredoxin-peroxiredoxin pathway in leaves exposed to NO2, thus regulating their redox balance. Furthermore, exogenous Mel mediated the polyamine synthesis pathway and increased the expression of the key enzyme proteins SAMS1, SAMS2, and SAMS3 in the polyamine synthesis pathway in leaves under NO2 stress. Mel regulated ABA signal transduction and calmodulin binding transcription factors CAMTA12 and NtCaM calmodulin NtCaM2 in Ca2+ signal transduction. Collectively, these results elucidate that Mel can alleviate high-concentration NO2, thus suitable for agricultural application.

To explore the mechanisms underlying the action of the heavy metals Cd and Zn on the photosynthetic function of plant leaves, the effects of 100 μmol L−1 Cd and 200 μmol L−1 Zn stress (the exposure concentrations of Cd and Zn in the culture medium were 2.24 mg kg−1 and 5.36 mg kg−1) on the chlorophyll and carotenoid contents as well as the photosynthetic function of tobacco leaves (Long Jiang 911) were studied. The key proteins in these physiological processes were quantitatively analyzed using a TMT-based proteomics approach. Cd stress was found to inhibit the expression of key enzymes during chlorophyll synthesis in leaves, resulting in a decrease of the Chl content. However, Zn stress did not significantly influence the chlorophyll content. Leaves adapted to Zn stress by upregulating CAO expression and increase the Chl b content. Although the Car content in leaves did not significantly change under either Cd or Zn stress, the expressions of ZE and VDE during Car metabolism decreased significantly under Cd stress. This was accompanied by damages to the xanthophyll cycle and the NPQ-dependent energy dissipation mechanism. In contrast, under Zn stress, leaves adapted to Zn stress by increasing the expression of VDE, thus improving NPQ. Under Cd stress, the expressions of three sets of proteins were significantly down-regulated, including PSII donor-side proteins (PPD3, PPD6, OEE1, OEE2-1, OEE2-2, OEE2-3, and OEE3-2), receptor-side proteins (D1, D2, CP43, CP47, Cyt b559α, Cyt b559β, PsbL, PsbQ, PsbR, Psb27-H1, and Psb28), and core proteins of the PSI reaction center (psaA, psaB, psaC, psaD, psaE-A, PsaE-B, psaF, psaG, psaH-1, psaK, psaL, psaN, and psaOL). In comparison, only eight of the above proteins (PPD6, OEE3-2, PsbL, PsbQ, Psb27-H1, psaL, and psaOL) were significantly down-regulated by Zn stress. Under Cd stress, both the donor side and the receptor side of PSII were damaged, and PSII and PSI experienced severe photoinhibition. However, Zn stress did not decrease either PSII or PSI activities in tobacco leaves. In addition, the expression of electron transport-related proteins (cytb6/f complex, PC, Fd, and FNR), ATPase subunits, Rubisco subunits, and RCA decreased significantly in leaves under Cd stress. However, no significant changes were observed in any of these proteins under Zn stress. Although Cd stress was found to up-regulate the expressions of PGRL1A and PGRL1B and induce an increase of PGR5/PGRL1-CEF in tobacco leaves, NDH-CEF was significantly inhibited. Under Zn stress, the expressions of ndhH and PGRL1A in leaves were significantly up-regulated, but there were no significant changes in either NDH-CEF or PGR5/PGRL-CEF. Under Cd stress, the expressions of proteins related to Fd-dependent nitrogen metabolism and reactive oxygen species (ROS) scavenging processes (e.g., FTR, Fd-NiR, and Fd-GOGAT) were significantly down-regulated in leaves. However, no significant changes of any of the above proteins were identified under Zn stress. In summary, Cd stress could inhibit the synthesis of chlorophyll in tobacco leaves, significantly down-regulate the expressions of photosynthesis-related proteins or subunits, and suppress both the xanthophyll cycle and NDH-CEF process. The expressions of proteins related to the Fd-dependent nitrogen metabolism and ROS scavenging were also significantly down-regulated, which blocked the photosynthetic electron transport, thus resulting in severe photoinhibition of both PSII and PSI. However, Zn stress had little effect on the photosynthetic function of tobacco leaves.

Cadmium stress causes a decrease in chlorophyll content and inhibits photosynthesis in tobacco leaves. The role of thioredoxin-like protein CDSP32 expressed in plant chloroplasts is to alleviates the reduced enzymes expression involved in chlorophyll synthesis of tobacco leaves due to Cd exposure, effectively preventing chlorophyll degradation and promoting increased tobacco biomass. Overexpression of Trx CDSP32 can protect the oxygen-evolving complex on the PSII donor side and promote electron transfer on the PSII acceptor side of tobacco leaves under Cd stress. Trx CDSP32 not only significantly increase the PSI activity of tobacco leaves, but also alleviate cadmium-induced PSI photoinhibition. Although Trx CDSP32 has no significant effect on the expression of PC and FNR proteins in tobacco leaves under Cd stress, it can alleviate the decreased expression of protein subunits involved in photosynthetic electron transfer such as Cyt b6/f complex subunits, Fd, and ATP synthase subunits. Trx CDSP32 can promote the synthesis of chlorophyll, stabilize the electron transfer chain, and promote ATP synthase activity to alleviate cadmium-induced photoinhibition of PSII and PSI in tobacco leaves.

Recently, studies on the use of polymer nanomaterial composites as pour-point depressants (PPD) have drawn much attention, but the crystallization properties and improved rheological performance of waxy crude oils using nanoclay-based composite PPDs have rarely been reported. In this paper, montmorillonite (Mnt) was first organically modified using octadecyltrimethylammonium chloride (C21H46NCl, or stearyltrimethylammonium chloride) in aqueous solution. Then, the organically modified Mnt (OMnt) material was dispersed into a polyoctadecylacrylate (POA) matrix to prepare a POA/OMnt composite PPD by melt blending. The composition, structure, and morphology of Mnt, OMnt, and the POA/OMnt composite PPDs were investigated. The results showed that the OMnt and POA were compatible and that the OMnt was exfoliated into several sheets in the POA matrix. Subsequently, the isothermal crystallization kinetics of the POA/OMnt composite PPDs showed that small amounts of OMnt had a dramatic impact on POA chain motion during crystallization and facilitated POA crystallization. After it was added to a waxy crude oil, the POA/OMnt composite PPDs produced better rheological properties and performance than identical concentrations of the neat POA. The POA/OMnt composite PPDs can act as wax nucleation sites for wax molecule precipitation and result in larger and more compact wax crystal flocs, which adversely affect the formation of a wax crystal network and, thus, favor the improvement of waxy crude oil rheology.

In the previous work, we have reported that small dosages of the polymethylsilsesquioxane (PMSQ) microsphere can effectively improve the performance of the EVA pour point depressant (PPD) and the amount of EVA PPD adsorbed on the microsphere evidently influences the efficiency of the EVA/PMSQ composite particle. To further promote the adsorption of EVA on the microsphere and enhance the efficiency of the composite particle, here, the amino-functionalized PMSQ microspheres with different amino molar ratios (PAMSQ) are first synthesized and characterized. The flow behavior, exothermic crystallization and microstructure of the waxy crude oil undoped/doped with EVA, EVA/PMSQ and EVA/PAMSQ are systemically investigated. Results show that 50 ppm EVA PPD can greatly improve the flow behavior of the oil and small dosages (2.5 ppm) of PMSQ microsphere can significantly improve the performance of the EVA PPD. After the amino-functionalization, the flow improving efficiency of EVA/PAMSQ is further enhanced: the gelation point, G′, G″, apparent viscosity and yield stress of the oil sample decrease to a lower value. The best performance is found at adding 50 ppm EVA + 2.5 ppm PAMSQ-2 (with amino molar ratios at 15%). Compared to EVA/PMSQ, the EVA/PAMSQ exhibits a stronger nucleation effect to increase the WAT of the oil sample slightly, and outstandingly modifies the morphology of the precipitated wax crystals into larger and more compact flocs. The amino-functionalization facilitates more EVA PPDs adsorbing and concentrating on the PAMSQ microsphere, causing the formation of the EVA/PAMSQ composite particles. The composite particles provide stronger nucleation effect for the wax precipitation, resulting in larger and more compact wax microstructures and then further improving the flow behavior of the oil. The rheological improving performance of EVA/PAMSQ for the waxy crude oil increases with the increase of amino molar ratio and the efficiency of EVA/PAMSQ-2 reaches the best. When the amino molar ratio is too high (PMASQ-3), the PAMSQ-3 microsphere is unstable in oil phase and aggregates into large particle flocs, which inhibits the EVA adsorption on the PAMSQ-3 microsphere and then weakens the rheological improving efficiency of the EVA/PAMSQ-3 composite particle.

Here, we reported that by adjusting the stirring speed, condensation pH value, precursor concentration and reaction temperature, the morphologies of the polymethylsilsesquioxane (PMSQ) microsphere could be well controlled through the two-step sol-gel synthesis. Because of the specific structural property and strong hydrophobicity, the obtained PMSQ microsphere dispersed well in the ethylene-vinyl acetate copolymer (EVA) matrix to form EVA/PMSQ hybrid. Subsequently, the thermal properties of both EVA and EVA/PMSQ hybrid were investigated through the TGA and DSC tests. The presence of PMSQ microsphere generates a significant delay in the thermal degradation processes of EVA, thus improving the thermal stability of EVA. The PMSQ microsphere also obviously increases the onset crystallization temperature and the crystallization rate of EVA, meaning that adding PMSQ microsphere enhances the crystallization ability of EVA. Finally, by applying rheological tests and microscopic observation, EVA/PMSQ hybrid was found to further improve the flow behavior of Qinghai waxy crude oil than the neat EVA did. The EVA/PMSQ hybrid can act as heterogeneous nucleation templates of wax crystals, and favor the formation of wax crystal flocs with increased size and compactness, thus inhibiting the continuous wax crystal network structure and further improving the flow behavior of the waxy crude oil.

In part 1 (10.1021/acs.energyfuels.7b03657), the synergistic effect of ethylene–vinyl acetate copolymer (EVA) pour point depressant (PPD) and rensin-stabilized asphaltenes on improving the flowability of synthetic waxy oil has been verified. This paper is a continuous work studying the effect of the asphaltene content (0.01–3 wt %) on the synergistic effect between EVA PPD and resin-stabilized asphaltenes. The results showed that, in the absence of EVA and with the increase of the asphaltene content, the precipitated wax crystals of the waxy oil tend to grow gradually from initial big needle-like to smaller and more regular (spherical-like) particles with a larger amount; therefore, adding aphaltenes can only decrease the apparent viscosity of waxy oil at the temperature range slightly lower than the wax precipitation temperature (WPT) (the precipitated wax crystal amount is low), and the temperature range is broadened by increasing the asphaltene content. When the temperature is decreased far below the W...

Both polymeric pour point depressants (PPDs) and asphaltenes can improve the flowability of waxy oils. However, the effect of polymeric PPDs together with asphaltenes on the flowability of waxy oils is not clear. In this paper, the synergistic effect of ethylene–vinyl acetate (EVA) PPD (100 ppm) and resin-stabilized asphaltenes (0.75 wt %) on the flow behavior of model waxy oils (10–20 wt % wax content) was investigated through rheological tests, DSC analysis, microscopic observation, and asphaltenes precipitation tests. The results showed that the asphaltenes disperse well in the xylene/mineral oil solvent as small aggregates (around 550 nm) with the aid of resins. The EVA or asphaltenes alone moderately improve the flow behavior of waxy oils by changing the wax crystals’ morphology from long and needlelike to a large, radial pattern or fine particles, respectively. The wax precipitation temperatures (WPTs) of waxy oils are also slightly decreased by adding EVA or asphaltenes, meaning that the cocrystall...

In real crude-oil pipelines, the formed wax deposits could be heterogeneous along the radial or axial directions. However, studies on this aspect are scarce. In this paper, the effect of the polyoctadecyl acrylate (POA) wax inhibitor on the wax deposition of 10 wt % model waxy oil was investigated with the aid of an in-house wax deposition device, differential scanning calorimetry test, high-temperature gas chromatography–Fourier transform infrared analysis, and microscopic observation. The results showed that adding POA in the model waxy oil greatly modifies the morphology of precipitated wax crystals, thus greatly changing the wax deposition behavior of the oil. For oil sample 1 (without POA), the precipitated wax crystals (needle-like) more easily form porous network structures, causing the formation of a thick and porous wax deposit with relatively low WAT, wax conten,t and critical carbon number (CCN). With the increase of POA concentration (oil samples 2–5), the precipitated wax crystals become more...

Sorghum variety Longza 17 was used as the experimental organism in a study of the effects of different types of sodium salt (two neutral salts, NaCl and Na2SO4; and two alkaline salts, NaHCO3 and Na2CO3), at an equivalent Na+ concentration (100 mmol·L−1) on leaf growth parameters and PSII and PSI function by using the Fast Chlorophyll Fluorescence Induction Dynamics technique and 820 nm light reflectance curves. The results showed that at Na+ concentration of 100 mmol·L−1, different types of sodium salt stress significantly inhibited the growth of sorghum plants. Different types of sodium salt stress showed significant inhibition on the activities of PSII and PSI in sorghum leaves, the impact of different types of sodium salt on the activities of PSII and PSI in sorghum leaves was consistent, listed from greatest to least impact as Na2CO3 > NaHCO3 > Na2SO4 > NaCl. The effects of alkaline salt stress on the growth and photosynthetic properties of sorghum were greater than those under the neutral salt stress, therefore, in addition to considering the impact of Na+ concentration in the sorghum planting area, emphasis should also be given to the influence of the degree of alkalization, especially the higher alkalinity of Na2CO3.

In a previous work, the addition of the polymethylsilsesquioxane (PMSQ) microsphere (50–400 ppm) can improve the flow behavior of waxy crude oil through the spacial hindrance effect. However, the flow improving efficiency of the neat PMSQ microsphere is not as good as the traditional polymeric pour point depressants (PPDs). In this paper, the effect of the ethylene-vinyl acetate copolymer (EVA2806) PPD together with the PMSQ microsphere (with the size around 2 µm) on the flow behavior of a typical waxy crude oil was investigated. The results show that adding 50 ppm EVA PPD can greatly improve the flow behavior of the oil. The neat PMSQ microsphere cannot improve the flow behavior of the oil at small dosages (≤10 ppm), but can significantly improve the performance of the EVA PPD. The gelation point, G′, G″, transient apparent viscosity and yield stress of the oil decrease further after adding both 50 ppm EVA and a small amount of the PMSQ microsphere (≤10 ppm). The best flow improving efficiency is found at 50 ppm EVA + 2.5 ppm PMSQ. The addition of the PMSQ microsphere has little influence on the WAT and precipitated wax crystal amount of the oil doped with EVA, but outstandingly changes the morphology of the precipitated wax crystals into larger and more compact flocs. The adsorption tests show that the EVA molecules can adsorb and concentrate on the PMSQ microsphere, thus causing the formation of the EVA/PMSQ composite particles. The composite particles can act as nucleation templates for the wax precipitation, resulting in larger and more compact wax microstructures and then further improving the flow behavior of the oil. The PMSQ microsphere dosage and the amount of EVA PPD adsorbed on the microsphere obviously influence the performance of the composite particle with the best performance at 50 ppm EVA + 2.5 ppm PMSQ. The findings mentioned above provide a new way to improve the performance of polymeric PPDs efficiently.

Asphaltenes and organic acids are commonly-seen crude oil components possessing interfacial affinity. In this work, the co-adsorption behavior of asphaltenes and carboxylic acids and its effects on the emulsion stability are explored. Above all, the acids are found to deteriorate the stability of the original asphaltene-stabilized emulsion. Subsequently, the investigation of the co-adsorption behavior probes a competitive adsorption between the asphaltenes and acids. The interactions between the both components perform further contributions to the formation of the interfacial layer by affecting the dispersive state of asphaltenes. The decreasing dilational modulus of the interface and the decreasing crumpling ratio of the oil droplet with the addition of the acids both indicate a more compressible but weaker asphaltene-containing interfacial layer with the participation of the acids. The interactive mechanism is correlated with the dispersive state of the asphaltenes influenced by the acids, which is characterized by the conductivity and asphaltene precipitation experiments. The acids are verified to modify the dispersive state by combining with the asphaltenes and forming composite-like units, giving a better oil compatibility to the asphaltenes. With the changes in the alkyl chain length of the carboxylic acids, the oil compatibility of the acids changes correspondingly, thus influencing the combining tendency and the oil compatibility of the composite-like units. The hexadecanoic acid exhibits the strongest interactions with the asphaltenes among the acids.

SUMMARY Integrins are heterodimeric cell surface receptors composed of an α and β subunit that mediate cell adhesion to extracellular matrix proteins such as fibronectin. We previously studied integrin α5β1 activation during zebrafish somitogenesis, and in the present study, we characterize the integrin αV fibronectin receptors. Integrins are activated via a conformational change, and we perform single-molecule biophysical measurements of both integrin activation via fluorescence resonance energy transfer (FRET)-fluorescence lifetime imaging microscopy (FLIM) and integrin intra-heterodimer stability via fluorescence cross-correlation spectroscopy (FCCS) in living embryos. We find that integrin heterodimers that exhibit robust cell surface expression, including αVβ3, αVβ5, and αVβ6, are never activated in this in vivo context, even in the presence of fibronectin matrix. In contrast, activatable integrins, such as integrin αVβ1, and alleles of αVβ3, αVβ5, αVβ6 that are biased to the active conformation exhibit poor cell surface expression and have a higher intra-heterodimer dissociation constant (KD). These observations suggest that a weak integrin intra-heterodimer affinity decreases integrin cell surface stability and increases integrin activatability., Graphical Abstract, In brief Sun et al. examine fibronectin receptor biophysics in live embryos and find that many of these integrins are never activated along the zebrafish somite boundary. Integrins α5β1 and αVβ1 are activated, but integrins αVβ3, αVβ5, and αVβ6 exhibit no activity. Integrin intra-heterodimer affinity appears to determine how readily an integrin is activated.

Dissolution of CO 2 in crude oil can change its rheological properties notably, thus implying a broad application prospect in the fields of oil flooding and transportation. In this study, a pressurized stirring-viscometric apparatus was designed based on the stirring-viscometric theory, and the corresponding viscometric method was also proposed. On the basis of the newly developed apparatus and method, the effects of pressure, shear rate and temperature on the apparent viscosity of CO 2 -heavy oil mixture were probed. It was found that the apparent viscosity of CO 2 -heavy oil mixture decreases exponentially with the increase of pressure. It only needs the pressure of 2 MPa for the apparent viscosity to decrease dramatically, which is far better than the viscosity-reducing efficiency of N 2 under the same condition. Meanwhile, the shear thinning feature becomes more and more obvious with increasing pressure of CO 2 . Moreover, the viscosity reducing rate of CO 2 -heavy oil mixture becomes larger with decreasing temperature, while the opposite trend is true for N 2 -heavy oil mixture. The results of this study provide strong technical support for the feasibility of transporting viscosity-reduced heavy crude oil by CO 2 .

The W/O emulsion formed by waxy crude oil tends to gelatinize under low-temperature gathering conditions, which may harm the flow assurance of multiphase transportation. This study mainly focused on the wax-precipitating gelation process of crude oil emulsions, and the structural differences of the emulsions with different water fractions at their gelation temperatures (GTs). First, the changes of wax appearance temperature (WAT) and precipitated wax amount at GT with variable water cut were investigated by DSC. Then, the specific structural properties of these different water cut emulsions at their own GTs were investigated by viscoelastic, yielding behavior, and structural breakdown experiments. On these bases, the gelation mechanism of a waxy crude oil emulsion was deduced. The WAT of a waxy crude oil emulsion was found to rise, evidently with the addition of dispersed water, verifying that water droplets provide necessary nucleation sites for paraffins and thus make them more prone to precipitate. Whe...

Light quality can influence the photosynthetic characteristics, morphology and physiological processes of plants. To investigate the effects of different light qualities (white light, W; red light, R; blue light, B; mixture of red and blue light, RB) of light emitting diodes (LEDs) and white cold fluorescent lamp on the growth and morphology of fruiting mulberry plants (Morus alba L. cv. ‘Longsang No.1’), fruiting mulberry plants were grown under different light qualities: W, R, B and RB of the same photosynthetic photo flux density (PPFD; 100 μmol m-2 s-1) for 20 d. Our results showed that stem length and leaf area of plants grown under R were the highest. However, stem length and leaf area of plants grown under B were lowest. Dry weights (DW), leaf mass per area (LMA), chlorophyll a/b ratio, soluble protein content, sucrose and starch content, and total leaf nitrogen (N) content of plants grown under R were the lowest. Net photosynthetic rate (Pn), stomatal conductance (gs), and actual photochemical efficiency of PSII (ΦPSII) of plants grown under RB were similar to plants grown under W. Net photosynthetic rate (Pn) and ΦPSII of plants grown under R and B were lower than plants grown under W and RB. Antioxidant enzymes activity of plants grown under R, RB and B were higher than plants grown under W. The number of leaf stomata, leaf thickness, palisade tissue length and spongy tissue length were the lowest in plants grown under R. The number of leaf stomata, leaf thickness and palisade tissue length of plants grown under RB and B were higher than plants grown under R. The results of this study indicate that a certain ratio of mixed red and blue LEDs light can reduce adverse effects of monochromatic red and blue LEDs light on fruiting mulberry growth and development.

Water-in-waxy crude oil emulsion tends to gelatinize under shutdown conditions when the atmospheric temperature or sea water temperature is lower than its pour point, threatening pipeline restart safety. Based on previous researches about the complex rheological properties of waxy crude oil emulsion gel, elasto-viscoplastic thixotropic models were first compared with each other according to experimental results, and the model proposed by Teng was screened out to be the most accurate one that could describe the whole response after shear loading. Then the effects of rheological changes on pipeline start-up flow after the formation of emulsion gel were computed numerically with the help of this thixotropic model. It was found out through a case study of a 50 km long pipeline that the time for the flow to start and from start state to steady state at terminal of the pipeline transporting 30% water cut emulsion gel increases by 5.8 times and 2.1 times respectively when compared with the time for original crude oil. Meanwhile, the steady flow rate after start-up decreases dramatically by 85.9%. The pipeline transporting waxy crude oil could be restarted successfully at the pressure of 1.0 MPa, while it need to be pressurized to 5.0 MPa to resume flow when its 60% water cut emulsion gel is formed. All these results indicate that the emulsification of waxy crude oil makes pipeline restart more difficult, and the lengthening of the pipeline magnifies the influence of the emulsification. Therefore, the possibility of wax precipitation in crude oil emulsion and further the structural characteristics of the formed emulsion gel have to be taken into consideration during multiphase pipeline shutdown.

The novel and effective nanocomposite PPD has garnered attention for its potential application in pipelines transporting waxy crude oil. In this paper, melt blending method was used here to prepare the poly(octadecyl acrylate) (POA)/clay nanocomposite PPD, which shows much better performance on waxy crude oil. The effects of the POA and POA/clay nanocomposite PPDs on the structural properties of gelled Changqing waxy crude oil were well studied through rheological tests, DSC analyses and microscopic observation. The precipitated wax crystal amount of the crude oil at low temperatures does not change with the addition of POA and nanocomposite PPDs, but the addition greatly weakens the structure of the gelled crude oil. Compared with the same dosage of POA, the addition of nanocomposite PPD further inhibits the formation of wax crystal’s network and further weakens the structural strength and viscoelasticity of the gelled crude oil. Increasing the dosage of nanocomposite PPD favors the weakening of the gelled crude oil structure. The nanocomposite PPD particles can act as nucleation templates of wax crystals and further weaken the gelled structure of waxy crude oil. In addition, we deduce that controlling the dispersed state of polymeric PPDs in oil phase could control the performance of the polymeric PPDs. The decrease of the mean nanocomposite PPD particle size from 6 μm (prepared by solvent blending) to 2 μm (prepared by melt blending) changes the dispersed state of POA molecules in oil phase and thus greatly enhances the performance of nanocomposite PPD.

Background The PLASMIC score was recently published to aid in the early identification of thrombotic thrombocytopenic purpura (TTP) patients. This study aims to evaluate whether this score is suitable for Chinese suspected TTP patients and find the utility of patients' other characteristics in predicting severe ADAMTS13 deficiency. Methods We retrospectively studied a Chinese cohort of 38 consecutive hospitalized patients with suspected TTP, ADAMTS13 test results, and other clinical data from September 2016 to May 2018. The predictive power of PLASMIC score in our cohort was evaluated, and patients' other characteristics, especially the high lactate dehydrogenase/the upper limit of normal (LDH/ULN), were studied to determine their distinguishing ability for TTP patients. Results In this Chinese cohort, 17 patients were diagnosed with TTP according to ADAMTS13 activity results. When dichotomized at intermediate-high risk (scores 5-7) vs low risk (scores 0-4), the PLASMIC score predicted TTP with a sensitivity of 100%, a specificity of 9.52%, and a misdiagnosis rate of 90.48%. And the LDH/ULN alone, or plus platelet count, reticulocyte percentage and indirect bilirubin (IBIL) both had excellent predictive power (area under the curve [AUC] 0.937, 95% confidence interval [CI] 0.863-1.000, P = .000, and AUC 0.994, 95% CI 0.980-1.000, P = .000, respectively). The model including platelet count, reticulocyte percentage, IBIL, and LDH/ULN ratio had a sensitivity of 100%, a specificity of 95.2%, and a misdiagnosis rate of 4.8%. Conclusions A modified PLASMIC score plus LDH/ULN ratio might be more suitable for identifying ADAMTS13 deficiency patients, especially for making an earlier diagnosis, guiding the immediate and reasonable plasma exchange, and also avoiding unnecessary allocation of plasma.

A better understanding of soil fungal communities is very useful in revealing the effects of an agroforestry system and would also help us to understand the fungi-mediated effects of agricultural practices on the processes of soil nutrient cycling and crop productivity. Compared to conventional monoculture farming, agroforestry systems have obvious advantages in improving land use efficiency and maintaining soil physicochemical properties, reducing losses of water, soil material, organic matter, and nutrients, as well as ensuring the stability of yields. In this study, we attempted to investigate the impact of a mulberry/alfalfa intercropping system on the soil physicochemical properties and the rhizosphere fungal characteristics (such as the diversity and structure of the fungal community), and to analyze possible correlations among the planting pattern, the soil physicochemical factors, and the fungal community structure. In the intercropping and monoculture systems, we determined the soil physicochemical properties using chemical analysis and the fungal community structure with MiSeq sequencing of the fungal ITS1 region. The results showed that intercropping significantly improved the soil physicochemical properties of alfalfa (total nitrogen, alkaline hydrolysable nitrogen, available potassium, and total carbon contents). Sequencing results showed that the dominant taxonomic groups were Ascomycota, Basidiomycota, and Mucoromycota. Intercropping increased the fungal richness of mulberry and alfalfa rhizosphere soils and improved the fungal diversity of mulberry. The diversity and structure of the fungal community were predominantly influenced by both the planting pattern and soil environmental factors (total nitrogen, total phosphate, and total carbon). Variance partitioning analysis showed that the planting pattern explained 25.9% of the variation of the fungal community structure, and soil environmental factors explained 63.1% of the variation. Planting patterns and soil physicochemical properties conjointly resulted in changes of the soil fungal community structure in proportion.

Valsa canker, caused by the fungus Valsa mali, is one of the most destructive diseases of apple in the primary production areas of China and other East Asian countries. Currently, there are no effective control methods for this disease. We investigated the occurrence of Valsa canker in 24 apple orchards in Shaanxi Province in concert with foliar nutrient analysis, and found that there was a significant negative correlation of leaf potassium (K) content with incidence and severity of Valsa canker. Fertilization experiments showed that increasing tree K content enhanced resistance to pathogen colonization and establishment. Apple trees with leaf K content greater than 1.30% exhibited almost complete resistance to Valsa mali. Field trials demonstrated that increasing K fertilization could significantly reduce disease incidence. Improved management of tree nutrition, especially K content, could effectively control the occurrence and development of Valsa canker.

Marssonina blotch, caused by the fungus Marssonina coronariae, is a serious foliar disease on apple in East Asia as well as in other moist temperate regions in Asia, Europe, and South America. Several fungicides were investigated for their toxicity to mycelial growth and conidial germination of the pathogen in vitro. Tebuconazole, kresoxim-methyl, hexaconazole, propiconazole, and a mixture of tebuconazole and benziothiazolinone sharply inhibited mycelial growth but had less effect on conidial germination. Field tests were conducted in a commercial orchard in Baishui County, Shaanxi Province, China, during 2012, 2013, 2014, and 2015 in order to develop recommendations for apple growers. Three applications of tebuconazole, hexaconazole, propiconazole, or a mixture of tebuconazole and benziothiazolinone at 20-day intervals from early July to late August resulted in defoliation incidence of

As the complex component in crude oil, asphaltenes adsorb at the interface and exhibit unique interfacial properties, ruling the emulsifying properties and emulsion stability of produced fluid. Hence, this study deals with the adsorption behavior and interfacial dilational properties of asphaltenes. To investigate the adsorption behavior of asphaltenes, the dynamic interfacial tension is obtained with the pendant drop shape method at various concentrations and temperatures. Based on the adsorption kinetic equation, the adsorption behavior is found to be controlled by different mechanisms at different stages. The initial stage is dominated by the diffusion mechanism. Then, the adsorption process is gradually affected by diffusion and random sequential adsorption simultaneously. Finally, the controlling factor changes to the random sequential adsorption of adsorbed asphaltenes. A higher concentration of asphaltenes can accelerate the diffusion coefficient by increasing the concentration gradient, while the effect of temperature is weaker than concentration. Based on the experimental results, a new method is developed to quantify the influences of different mechanisms. After that, the droplet dilation experiment is carried out to probe the structural properties of the formed interfacial layer. By fitting the experimental data with the Langmuir equation of state, the average interfacial area occupied per asphaltene molecule is calculated. Finally, the emulsion stability experiments are carried out to support the conclusions in the interfacial experiments. This study enriches the adsorption kinetics theory of asphaltenes. It also contributes to the safe and economical transportation of produced fluid and rises the efficiency of demulsification.

The polyoctadecyl acrylate (POA), polyoctadecyl acrylate-vinyl acetate (POA-VA), polyoctadecyl acrylate-maleic anhydride (POA-MA), and polyoctadecyl acrylate-styrene (POA-St) were synthesized and used as pour point depressants (PPDs). The performance of the PPDs first increases with the increase of polar group (MA or VA) content, and then decreases with the further increase of polar group (MA or VA) content. The POA-VA PPDs show the best performance at the OA:VA molar ratio 3:1, whereas the POA-MA PPDs shows the best performance at the OA:MA molar ratio 7:1. The performance of POA-St PPDs decreases outstandingly with the increase of the nonpolar St molar fraction.

The yield stress and pour point are two important parameters related to flow assurance problems in waxy crude oil pipelines. The yield stresses at temperatures below the pour points of five waxy crude oils after heating to different temperatures have been investigated in the present paper. Both the experimental results in this work and data from the literature show that the yield stress values increase exponentially with the decreasing measurement temperature. The experimental results show that the heating temperature has an obvious influence on the yield stress and the pour point. However, it was noted that the yield stress values at the gel point temperature, defined as the highest temperature at which the movement of the sample cannot be observed during the quiescent pour point testing process, are approximately the same for a waxy crude oil after heating to different temperatures. An exponential relationship exists between the yield stress and the difference between the measurement temperature and gel point that is independent of the heating temperature. To explore this phenomenon, the relative magnitudes of the gravitational stress and the structural strength of the wax crystal network during the gel point test has been analyzed, and it was found that the yield stress value at the gel point has a favorable linear relationship with the oil density.

In order to find out the response mechanism of nitrogen assimilation and glutamine/glutamine family of amino acids metabolism in mulberry (Morus alba L.) leaves under NaCl and NaHCO(3) stress, and to reveal its role in salt alkali adaptation. The effects of the nitrogen metabolism of mulberry leaves were studied under 100 mmol L(−1) NaCl and NaHCO(3) stress.The results showed that the activity of NR and the content of TN and SP did not change significantly, the expression of NiR, Fd-NiR, Fd-NiR gene and theactivity of NiR increased significantly under NaCl stress, but nitrogen assimilation was inhibited under NaHCO(3) stress. NaCl stress had no significant effect on the expression and activity of GS and GOGAT in mulberry leaves. Under NaHCO(3) stress, the expression of Fd-GOGAT, Fd-GOGAT2, Fd-GOGAT gene, and the activity of GS and GOGAT were significantly decreased. NaCl stress can promote the accumulation of Pro, Put and Spd in mulberry leaves. The accumulation of Pro under NaHCO(3) stress is greater than that under NaCl stress. NaCl stress also induced the up-regulation of GAD, GAD1 and GAD1 gene expression, so promoting the synthesis of GABA may be an adaptive mechanism for mulberry to cope with NaCl stress, but the expression of GAD did not change significantly and GAD gene expression lower than CK under NaHCO(3) stress. Although both NaCl and NaHCO(3) stress could promote the synthesis of GSH by up-regulation of GCLM expression, GSH under NaHCO(3) stress was significantly higher than that under NaCl stress, the content of H(2)O(2) was still significantly higher than that of NaCl stress, that means GSH may not play a key role in alleviating the oxidative damage in mulberry leaves caused by salt and alkali.

Asphaltenes can adsorb at the interface between crude oil and produced water and form a defensive interfacial layer to stabilize emulsions. This paper details the effects of the polarities of asphaltene subfractions on emulsion stability and interfacial properties. Asphaltene subfractions with different polarities were first obtained by a solvent-precipitation method, followed by the characterization of their molecular structures and dispersive states in the model oil. The results show that the subfractions with lower polarity contain a higher proportion of aliphatic groups, which benefits oil compatibility, thus leading to a better dispersive state and weaker aggregation tendency. Then, the stabilities of the emulsions prepared with these subfractions were explored at different concentrations. The emulsion stability worsens as polarity weakens at 500 ppm. However, at a concentration of 5000 ppm, the emulsion stability increases first with a polarity decrease, reaches a peak, and then decreases. The adsorption behavior and interfacial structural strength are detected through dynamic interfacial tension and dilational viscoelastic experiments. The subfractions with lower polarities exhibit better dispersion in the model oil, allowing for higher rates of absorption. The dilational modulus and emulsion stability depend on the migration rate and surface coverage of the subfractions and share similar trends with changes in polarity. With an increase in the polarity of the subfractions, the surface coverage and migration rate have reverse contributions on the dilational modulus and emulsion stability. Additionally, the contributions become more obvious after asphaltene aggregation.

In oil fields, ethylene–vinyl acetate copolymers (EVA) are often added to the produced fluid as flow improvers. Asphaltenes in the crude oil and EVA can both adsorb at the interface and form a protective interfacial layer, affecting the emulsion stability of produced fluid. In this study, the effects of the interactions between asphaltenes and EVAs with different VA contents on the oil/water interfacial properties are investigated. To explore the adsorption behavior of asphaltenes and EVAs, the dynamic interfacial tension is firstly measured with droplet shape analysis method. The effects of the interactions between asphaltenes and EVAs are observed by analyzing the dynamic interfacial tension of the binary system and that of the single system. The added EVAs participate in the formation of interfacial layer and motivate the interfacial activity of asphaltenes to different degrees by influencing the dispersion state of asphaltenes in the model oil. The dilational modulus is then obtained by interfacial small-amplitude oscillation method. The addition of EVAs decreases the modulus, weakening the structure of interfacial layer. The conductivity experiment, asphaltene precipitation experiment and dynamic lighting scattering experiment are combined to explore the effect of EVAs on the dispersion state of asphaltenes. The polar moieties of EVAs interact with asphaltenes and form composite particles with peripheral nonpolar moieties, thus inhibiting asphaltenes from aggregation and improving the dispersion state. Among all the EVAs in this study, the EVA with 30% VA content has the strongest influence on the dispersion state of asphaltenes.

Asphaltenes in waxy crude oils greatly influence the performance of polymeric pour point depressants (PPDs), and the relevant mechanism needs to be further discovered. In this article, polyoctadecylacrylate (POA), polyoctadecyl-acrylate-maleic anhydride (POA-MA) and its aromatic pendants-modified derivatives, polyoctadecyl-acrylate-maleic anhydride-aniline (POA-MA-AN) and polyoctadecyl-acrylate-maleic anhydride-naphthylamine (POA-MA-NA) were synthesized and characterized. Subsequently, the performance of the four PPDs on the pure model waxy oil (MO-1) and the model waxy oil containing 0.3 wt% asphaltenes (MO-2) were investigated through the rheological test, DSC analysis and micro-observation. The results showed that the four PPDs could improve the flowability of MO-1 to some extent, and adding 500 ppm POA exhibited the best performance: the pour point decreased from the initial 29 °C to 22 °C and the yield stress at 10 °C reduced from the initial 627.20 Pa to 69.58 Pa. Adding comb-like PPDs could observably improve the flowability of MO-2, meaning that a synergistic effect exits between the asphaltenes and comb-like PPDs. Adding 500 ppm POA-MA-AN in MO-2 showed the best performance: the pour point decreased to 3 °C, the yield stress at 10 °C reduced to 1.27 Pa. The quantitative asphaltenes precipitation test and molecular dynamics simulations revealed that adding POA-MA-AN could significantly reduce the percentage of precipitated asphaltenes in the mixed solution and the interaction energy between POA-MA-AN and asphaltenes was the lowest. This indicates that introducing aromatic pendants in comb-like PPDs strengthens the interactions between asphaltenes and PPDs, facilitating the adsorption of PPDs on asphaltenes to form the composite particles and thus greatly improving the flowability of waxy oils.

Zhishi (ZS) and Zhiqiao (ZQ) are two important traditional Chinese medicines (TCMs) that exert various pharmacological functions due to their active ingredients. However, the oral absorption of these ingredients requires further study. At the early drug discovery stage, the high-throughput parallel artificial membrane permeability assay (PAMPA) is one of the most frequently used to predict transcellular passive absorption in in-vitro models. This study aims to establish a new approach to examine an optimal extraction process that can take into account not only the concentration of active ingredients but also the overall absorption properties of the mixtures extracted from TCMs. A high-performance liquid chromatography triple-quadrupole mass spectrometry (HPLC-QqQ-MS/MS) method was validated for the determination of the effective permeability value (Pe) applied to the above experimental medium. The PAMPA experiment showed that certain active ingredients such as diosmin, rhoifolin, eriocitrin, narirutin, naringin, hesperidin and neohesperidin were not detected in the permeability assay of mono-constituents but were well detected and achieved a better absorption in the permeability assay of the mixture, indicating that certain unknown ingredients may act as cosolvents to improve the solubility or permeability of other ingredients. Furthermore, solid phase extraction (SPE) as an enrichment and purification process enhances absorption. In the present study, a novel in vitro approach was developed to decipher the potential role of TCMs in global absorption, and the extraction process for complex TCMs was described and systematically optimized.

The cyclic electron flux (CEF) around photosystem I (PSI) was discovered in isolated chloroplasts more than six decades ago, but its quantification has been hampered by the absence of net formation of a product or net consumption of a substrate. We estimated in vivo CEF in leaves as the difference (ΔFlux) between the total electron flux through PSI (ETR1) measured by a near infrared signal, and the linear electron flux through both photosystems by optimised measurement of chlorophyll a fluorescence (LEFfl). Chlorophyll fluorescence was excited by modulated green light from a light-emitting diode at an optimal average irradiance, and the fluorescence was detected at wavelengths >710 nm. In this way, LEFfl matched the gross rate of oxygen evolution multiplied by 4 (LEFO2) in broad-spectrum white actinic irradiance up to half (spinach, poplar and rice) or one third (cotton) of full sunlight irradiance. This technique of estimating CEF can be applied to leaves attached to a plant.

Fluorescent proteins are transformative tools; thus, any brightness increase is a welcome improvement. We invented the "vGFP strategy" based on structural analysis of GFP bound to a single-domain antibody, predicting tunable dimerization, enhanced brightness (ca. 50%), and improved pH resistance. We verified all of these predictions using biochemistry, crystallography, and single-molecule studies. We applied the vsfGFP proteins in three diverse scenarios: single-step immunofluorescence in vitro (3× brighter due to dimerization); expression in bacteria and human cells in vivo (1.5× brighter); and protein fusions showing better pH resistance in human cells in vivo. The vGFP strategy thus allows upgrading of existing applications, is applicable to other fluorescent proteins, and suggests a method for tuning dimerization of arbitrary proteins and optimizing protein properties in general.