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Background: Chimeric antigen receptor natural killer (CAR-NK) cells represent a promising advancement in CAR cell therapy, addressing limitations observed in CAR-T cell therapy. However, our prior study revealed challenges in CAR-NK cells targeting CD19 antigens, as they failed to eliminate CD19+ Raji cells in NSG tumor-bearing mice, noting down-regulation or loss of CD19 antigen expression in some Raji cells. In response, this study aims to enhance CD19 CAR-NK cell efficacy and mitigate the risk of tumor recurrence due to target antigen escape by developing CD19 and CD20 (CD19/CD20) dual-targeted CAR-NK cells. Methods: Initially, mRNA encoding anti-CD19 CARs (FMC63 scFv-CD8α-4-1BB-CD3ζ) and anti-CD20 CARs (LEU16 scFv-CD8α-4-1BB-CD3ζ) was constructed via in vitro transcription. Subsequently, CD19/CD20 dual-targeted CAR-NK cells were generated through simultaneous electrotransfection of CD19/CD20 CAR mRNA into umbilical cord blood-derived NK cells (UCB-NK). Results: Following co-electroporation, the percentage of dual-CAR expression on NK cells was 86.4% ± 1.83%, as determined by flow cytometry. CAR expression was detectable at 8 h post-electric transfer, peaked at 24 h, and remained detectable at 96 h. CD19/CD20 dual-targeted CAR-NK cells exhibited increased specific cytotoxicity against acute lymphoblastic leukemia (ALL) cell lines (BALL-1: CD19+CD20+, REH: CD19+CD20−, Jurkat: CD19−CD20−) compared to UCB-NK, CD19 CAR-NK, and CD20 CAR-NK cells. Moreover, CD19/CD20 dual-targeted CAR-NK cells released elevated levels of perforin, IFN-γ, and IL-15. Multiple activation markers such as CD69 and cytotoxic substances were highly expressed. Conclusions: The creation of CD19/CD20 dual-targeted CAR-NK cells addressed the risk of tumor escape due to antigen heterogeneity in ALL, offering efficient and safe 'off-the-shelf' cell products. These cells demonstrate efficacy in targeting CD20 and/or CD19 antigens in ALL, laying an experimental foundation for their application in ALL treatment. [ABSTRACT FROM AUTHOR]

The application of bamboo fibers (BFs) as a reinforcing filler in polylactic acid (PLA) is hindered by their poor compatibility owing to the intrinsic hydrophilia of BFs and the hydrophobicity of PLA. To solve this issue, cardanol (CD) and epoxidized cardanol glycidyl ether (ECGE) were used as compatibilizers to strengthen and toughen PLA/BF bio‐composites, to the best of our knowledge, preparing PLA/BF/CD and PLA/BF/ECGE bio‐composites. The impact strengths of the synthesized bio‐composites increased from 7.75 to 23.75 and 7.75 to 23.95 kJ/m2, respectively, compared with that of a PLA/BF composite without compatibilizer. The investigation of the mechanical properties, crystallization, fractured surface morphology, and solvent stress‐cracking resistance properties revealed that the toughening mechanism of the PLA/BF/CD bio‐composites are mainly based on the plasticization of CD, which results in high impact toughness but low tensile strength. Moreover, the modification with ECGE improves the impact and tensile strengths of the bio‐composite owing to the following factors: (1) the epoxy groups of ECGE generate strong interactions with the BF surface and PLA to form an enhanced interfacial structure; (2) when present at high concentrations, chain extension reaction between ECGE and PLA to increase the molecular chain entanglement of PLA; and (3) upon curing and crosslinking, ECGE forms an entangled network structure that toughens the matrix. [ABSTRACT FROM AUTHOR]

The occupation tendencies of Cr, Cu, Mo, Nb, Ni, Ti and V in Fcc-Fe stacking fault containing vacancy were studied by the first principles calculations. The effects of C, N and Nb, Ti co-segregation in the region of vacancy is discussed. The results are as follows: the substitutional elements Cr, Cu, Mo, Ni, Nb, Ti and interstitial elements C, N have no segregation tendency at the stacking fault of Fcc-Fe (111) plane. When the stacking fault contains vacancy, the above elements have the tendency to segregate around the vacancy, and C, N tend to occupy vacancy and their segregation tendency is the stronger than that of substitutional elements. C, N are easily co-segregated with Nb, Ti in the region of vacancy. It is difficult for Mo to aggregate around the carbonitride precipitates, which is conducive to the use of nano-scale carbide and nitride precipitation strengthening in high Mo austenitic steel, and simultaneously improves corrosion resistance. Nb and Ti tend to aggregate around the vacancy where occupied by C, N. [ABSTRACT FROM AUTHOR]

To overcome the migration of epoxidized soybean oil (ESO) used as a poly(vinyl chloride) (PVC) plasticizer, ESO‐branched cardanol (CD) ethers (ESO‐CDn) are designed and synthesized in this work. The incorporation of the benzene ring and the C15 straight chain of CD provided excellent plasticizing efficiency, and the increase in the molecular weight by branching CD with ESO enhanced the migration resistance of the plasticizer. In this work, two different methods are adopted to prepare PVC/ESO/CD and PVC/ESO‐CDn, namely the one‐step method (dynamic vulcanization of ESO, CD, and PVC) and the two‐step method (synthesis of ESO‐CD and then mixing it with PVC). The first method is convenient, while it is also uncontrollable, leading to an incomplete reaction between ESO and CD. The second method offers a controllable reaction between ESO and CD. The chemical structure of ESO‐CDn is fully characterized. Furthermore, the thermal, mechanical, rheology, and migration resistance properties of PVC/ESO/CD and PVC/ESO‐CDn are compared. The relationship between the molecular structure and plasticizer performance is investigated, and the plasticization mechanism is proposed. The tensile and thermal properties indicate that PVC/35ESO‐CD10 offered a superior anti‐thermal aging performance due to the excellent plasticizing and migration resistance effects of ESO‐CD10. [ABSTRACT FROM AUTHOR]

Due to the vital role of classroom communications in the success of EMI courses, factors driving students to communicate with teachers and classmates need to be recognized. In this respect, several scholars worldwide have explored different emotional, personal, and environmental sources of students' willingness to communicate (WTC). Nonetheless, the impacts of learning motivation and academic self-efficacy have somehow been overlooked in previous investigations. That is, few investigations have inspected the effects of these personal factors on students' decisions to speak. Additionally, no research study has been carried out on the consequences of motivation and self-efficacy for EMI students' decisions to communicate. To address the mentioned gaps, this investigation measured the influences of learning motivation and academic self-efficacy on Chinese EMI students' WTC. In doing so, three closed-ended questionnaires were given to 303 Chinese EMI students. Correlation tests indicated positive links between WTC, academic self-efficacy, and learning motivation. Regression analysis also demonstrated the significant, positive effects of learning motivation and academic self-efficacy on Chinese EMI students' WTC. The results of this inquiry could be beneficial for all EMI teachers and teacher trainers. [ABSTRACT FROM AUTHOR]

Sweet cherry is prone to senesce and decay due to high postharvest respiration rate and fungal infection. The effects of natamycin-chitosan coating on physicochemical and microbial properties of sweet cherries stored at 4 °C were investigated. Scanning electron microscopy results revealed that natamycin was more uniformly distributed on sweet cherry pericarps with the help of chitosan coating. Respiration rate of sweet cherries was suppressed by chitosan coating during the storage and as a result, total soluble solids (13.53 %–13.80 %) and titratable acidity (0.91 %–0.93 %) were remained higher values and weight loss (2.54 %–2.85 %) was decreased in chitosan and natamycin-chitosan groups. Although both natamycin and chitosan were effective in inhibiting yeast and mold, sweet cherries treated with the combination of natamycin and chitosan showed significantly lower yeast and mold count (3.31 log CFU/g) and decay rate (1.67 %) compared with control. Natamycin combined chitosan inhibited the pathogenic fungi of sweet cherries, such as Alternaria , Cladosporium and Penicillium. These results indicated that postharvest natamycin-chitosan coating has great advantages in maintaining fruit quality, inhibiting fungi, and reducing decay rate of sweet cherry. • Sweet cherries were coated with chitosan and natamycin. • Natamycin was uniformly distributed on sweet cherry by chitosan coating. • Chitosan was effective in maintain the physicochemical properties of sweet cherry. • Chitosan-natamycin coating inhibited pathogenic fungi of sweet cherry. [ABSTRACT FROM AUTHOR]

Aeromonas salmonicida is ubiquitously distributed in aquatic environments and is one of the major pathogens of freshwater aquaculture fish. Recent studies have demonstrated that A. salmonicida plays a crucial role in fish spoilage. In this study, a novel antibacterial agent, lactobionic acid (LBA), was investigated for its antibacterial effect against A. salmonicida. The results showed that the minimum inhibitory concentration (MIC) of LBA was 16 mg/mL. Bacterial cells dropped below the detection limit within 2 h after exposure to 2 MIC of LBA. The cells treated with LBA became rough and sunken, and LBA caused cellular protein leakage and an increase in conductivity. Transcriptomic analysis exhibited that the expression of 1273 genes in A. salmonicida was altered by LBA, including 700 down-regulated and 573 up-regulated genes. The most representative down-regulated genes were enriched in bacterial chemotaxis, two-component system and ATP-binding cassette transporter pathways. LBA showed an effective inhibitory effect on A. salmonicida in refrigerated grass carp and could prolong the storage time of grass carp. Overall, the intervention of LBA resulted in the decrease of cell chemotaxis and disturbance of cellular metabolic processes, which inhibited A. salmonicida. These results revealed the antibacterial mechanism of LBA against A. salmonicida , which provided a strategy for the control of fish spoilage. • LBA can effectively inhibit the growth of A. salmonicida. • LBA destroyed the integrity of cell membrane and caused protein leakage. • LBA disturbed the chemotaxis, two-component system and quorum sensing pathways. • LBA can prolong the storage time of refrigerated grass carp. [ABSTRACT FROM AUTHOR]

Background. Patients with stable chronic obstructive pulmonary disease (COPD) have been observed to benefit from tiotropium bromide. However, there are few studies of tiotropium bromide on sputum and sputum viscosity. To evaluate the effect of tiotropium bromide on mucus hypersecretion, a randomized, double-blind controlled trial was performed. Methods. 120 cases of patients with pulmonary function grade II were divided into two groups, which include the treatment group given tiotropium bromide powder inhalation (18 μg, inhalation, QD) and the control group given formoterol fumarate powder inhalation (12 μg, inhalation, BID) plus ambroxol hydrochloride tablets (60 mg, oral, TID). After 3 months of treatment, the pulmonary function and α1-acid glycoprotein (α1-AGP) in sputum were detected, and the changes of glycoprotein and Ca2+ content were evaluated by Miller classification. Results. Three patients (2 cases in the treatment group and 1 case in the control group) were dropped due to loss of follow-up, and 117 cases of patients were enrolled in this study. After 3 months of treatment, the sputum character score, α1-acid glycoprotein, Ca2+ content, and lung function of the two groups were significantly improved; group comparison analyses revealed that there was no significant difference in the content of α1-AGP, Ca2+ in sputum, and lung function between the two groups (P > 0.05), but the improvement of sputum properties was significant (P < 0.05), and the treatment group was better than the control group (t = − 2.77 ; P = 0.007). Conclusions. Inhaled tiotropium bromide can effectively inhibit the mucus hypersecretion in stable COPD patients, improve the sputum properties and lung function of patients, and improve the quality of life of patients. [ABSTRACT FROM AUTHOR]

COVID-19 pandemic has resulted in an unprecedented global public health crisis. It is obvious that SARS-CoV-2 vaccine is needed to control the global COVID-19 public health crisis. Since obvious advantages including fast manufacturing speed, potent immunogenicity and good safety profile, six mRNA vaccines have been used to prevent SARS-CoV-2 infections in clinic with lipid nanoparticles (LNP) formulation via intramuscular injection. In this work, we first constructed RBD-encoding mRNA (RBD-mRNA) formulated in liposomes (LPX/RBD-mRNA) and investigated the influence of administration routes on the immunogenicity. LPX/RBD-mRNA can express RBD in vivo and successfully induced SARS-CoV-2 RBD specific antibodies in the vaccinated mice, which efficiently neutralized SARS-CoV-2 pseudotyped virus. Moreover, the administration routes were found to affect the virus neutralizing capacity of sera derived from the immunized mice and the types (Th1-type and Th2-type) of cellular immune responses. This study indicated that liposome-based RBD-mRNA vaccine with optimal administration route might be a potential candidate against SARS-CoV-2 infection with good efficacy and safety. [Display omitted] [ABSTRACT FROM AUTHOR]

Polymers of intrinsic microporosity (PIMs) are a new type of polymer material with unique microporous structure and have been widely applied in gas separation. In recent years, PIMs have also experienced rapid growth in liquid separation and purification; however, so far, no review is reported on the application of PIMs in this field. This paper reports a comprehensive and critical review on the recent research progress of PIMs in the application of liquid separation and purification including membrane separation and adsorption. First, the structural characteristics and synthesis methods of PIMs are briefly described. Subsequently, their applications in membrane separation are described in detail, including pervaporation (removal of organics from water, dehydration of solvents, and separation of organic mixtures), nanofiltration (dye rejection), and adsorption (dyes, organic contaminants, metal ions, oil/water separation, and enantiomeric separation). The effect of material structure and modification on the separation performance is emphasized, and possible new research directions are mentioned. Finally, the application of PIMs in liquid separation and purification is prospected. In conclusion, PIMs exhibit excellent separation efficiency and stable operation characteristics in liquid separation and purification, and they have attractive and broad development prospects. More valuable applications remain to be developed. [ABSTRACT FROM AUTHOR]

The precipitation of the σ phase at the grain boundary (GB) has an important effect on the properties of super austenitic stainless steel. This study used density functional theory (DFT) calculations to assess the segregation of Mo and B atoms at the GB and their effects on GB strength. The results demonstrated that Mo and B atoms tend to converge to grain boundary positions and B atoms are easier to segregate than Mo atoms. In addition, B can restrain the segregation of Mo to grain boundary positions, making it difficult for the positions to form an σ phase. An analysis of the inhibitory effect of different contents of B on Mo indicated that higher B content is better for restraining Mo segregation to grain boundary sites. These results are beneficial for improving the shortcomings of super austenitic stainless steel. B can also increase the GB strength while inhibiting the segregation of Mo to grain boundary sites and a charge density analysis demonstrated the results. [ABSTRACT FROM AUTHOR]

Three bis(phenyl)fluorene-based cardo diamine monomers with different side groups (–CF3, –H, and –CH3) were synthesized and used to synthesize three 6FDA-based polyimides (6FDA-FBPF, 6FDA-BPF, and 6FDA-MBPF). The influence of bis(phenyl)fluorene cardo moiety and different side groups on the glass transition temperature (Tg), thermal stabilities, and chain packing of the synthesized polyimides were systematically studied. The gas permeabilities and selectivities of three bis(phenyl)fluorene-based polyimide membranes were studied and correlated with their fractional free volumes and chain packing conditions. As a result, the obtained polyimides showed promising performance for hydrogen separation. Among the three polyimides, 6FDA-FBPF had the highest gas permeabilities which exhibited H2 permeability of 151.12 Barrer and H2/CH4 selectivity of 62.19. The high gas separation performance of 6FDA-FBPF mainly attributed to the ineffective chain packing via the incorporation of bi(phenyl)fluorene cardo moiety and introduction of bulky CF3 side groups into the polyimide backbones that is favorable to formation hourglass-shaped pores. [ABSTRACT FROM AUTHOR]

Herein, we report an efficient nickel-catalyzed direct cyclization of amines with alcohols for the synthesis of various nitrogen containing heterocycles. These processes employ the sustainable “borrowing hydrogen” strategy and have many advantages, such as earth-abundant metal catalysts, easily available starting materials, wide synthetic versatility and harmless waste emission. [ABSTRACT FROM AUTHOR]

This study aimed to establish a quantitative structure–property relationship (QSPR) model for predicting the gas separation performance of polyimide membranes using neural networks combined with the repeat unit structure of materials. Using a data bank based on 125 polyimides, we calculated a total of 20 descriptors for all polyimides using Yampolskii's group contribution method, which divides polyimides' repeat units into their smallest groups. The number of groups contained in each polyimide is taken as the network input, and the gas permeability as the network output. Two neural network models, back-propagation (BP) and genetic algorithm-optimized back-propagation (GABP) algorithms, were used as the prediction model, and the prediction results were compared. When compared with the previous models used to predict the gas separation performance for all polymers and other machine learning (ML) models, the prediction results obtained using the GABP model are encouraging, showing a root mean squared error (RMSE) of 0.44 for CO 2 , indicating that the model is applicable to polyimide. In addition, the GABP model is easy to operate, requires few parameters, it is also applicable to copolyimides. The GABP model based on the group contribution method can thus satisfactorily predict polyimides' gas separation. This is expected to be used to guide the synthesis and structure screening of polyimides for saving resources and commercialization. [Display omitted] • A quantitative structure–property relationship (QSPR) model is established. • Neural network models are proposed to predict the gas permeability of polyimides. • The results show that GABP model achieves better results. • GABP model is applicable to copolymers. • GABP model requires few parameters and is easy to operate and extend. [ABSTRACT FROM AUTHOR]

Abstract: Polymers with rigid and contorted structures are always preferred for use as gas separation membranes. Owing to the contorted nature of the spiro‐center, the spirobichroman structure is an effective scaffold for impeding polymer chain packing. Two spirobichroman‐based diamines, 6,6′‐bis(4‐amino‐2‐trifluoromethylphenoxy)‐4,4,4′,4′,7,7′‐hexamethyl‐2,2′‐spirobichroman (FSBC) and 6,6′‐bis(4‐aminophenoxy)‐4,4,4′,4′,7,7′‐hexamethyl‐2,2′‐spirobichroman (SBC), with or without CF3 side groups are prepared. The two diamines are separately reacted with 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA) and 3,3′,4,4′‐diphenylsulfonetetracarboxylic dianhydride (DSDA) to obtain four spirobichroman‐based polyimides, denoted as BTDA‐FSBC, BTDA‐SBC, DSDA‐FSBC, and DSDA‐SBC. The different molecular structures among the four monomers are expected to alter the fractional free volume of the corresponding polyimides by impacting chain‐packing conditions, and then controlling the gas transport properties. Chemical structures, thermal and physical properties of the polyimides are fully characterized. Two different methods, molecular dynamics simulation and Bondi's group contribution method are employed to characterize the fractional free volumes (FFVs) of these polyimides. In the end, it is found that FSBC‐based polyimides exhibit relatively higher gas permeability than SBC‐based polyimides. [ABSTRACT FROM AUTHOR]

To improve fuel use and energy-conversion efficiency and reduce the emission of pollutants, oxygenation is now deemed an effective chemical treatment of water in supercritical and ultra-supercritical power plants. Supercritical water with dissolved oxygen significantly enhances the oxidation rate of steels in the main steam pipeline and super-heater header. However, at the atomic scale, the mechanism of metal oxidation in supercritical water containing dissolved oxygen is unknown and has not been investigated by simulation. In this work, the oxidation of iron in supercritical water containing dissolved oxygen is studied by ab initio molecular dynamics and first principles calculations. The results indicate that dissolved oxygen in supercritical water dramatically accelerates the oxidation of iron. With the help of oxygen, the decomposition of water occurs on the iron surface, thereby producing more iron oxides and iron hydroxides. Additionally, hydrogen peroxide (H2O2) forms as an intermediate product, instantaneously decomposing to form iron hydroxides, and this is another reason for the enhancement in the oxidation of steel by supercritical water containing dissolved oxygen. Based on the results from ab initio molecular dynamics, we develop herein typical models of water molecules and oxygen molecules reacting directly on the iron surface and then carry out first-principles calculations. The results show that water decomposes on the iron surface only with the assistance of adjacent oxygen molecules and in the absence of surrounding water molecules. This investigation deepens our understanding of the oxidation mechanism of metal in supercritical water containing dissolved oxygen. The ideas and methods implemented in this work can also be used to study other materials exposed to supercritical water involving oxygen. [ABSTRACT FROM AUTHOR]

A novel triptycene-based diamine, 2,6-diaminotriptycene-14-carboxylic acid, was synthesized and used for preparing carboxylic acid containing triptycene-based Tröger's base copolymers, CoPIM-TB-1 and CoPIM-TB-2, with another diamine monomer, 2,6-diaminotriptycene. The copolymers were subsequently post - crosslinked by glycidol to form C-CoPIM-TB-1 and C-CoPIM-TB-2. Glycidol crosslinking greatly impeded inter-chain mobility of the triptycene-based copolymers and subsequently restricted both physical aging rate and CO 2 induced plasticization. Gas permeabilities of 40 days old C-CoPIM-TB-2 film decreased by 7%, 5%, and 9%, to gases H 2 , CO 2 , and O 2 , respectively, which were slower than those of the uncrosslinked PIM-Trip-TB polymer of which permeabilities decreased by 21%, 42%, and 30%, respectively. Mixed gas permeation results showed no CO 2 induced plasticization at a CO 2 partial pressure up to 20 atm. Moreover, separation performance of C-CoPIM-TB-1 and C-CoPIM-TB-2 went over the Robeson 2008 upper bounds for gas pairs including O 2 /N 2 , CO 2 /CH 4 , CO 2 /N 2 and H 2 /N 2 . All these results indicated a great potential for the post-crosslinked Triptycene-Based Tröger's Base polymers for natural gas sweetening. [ABSTRACT FROM AUTHOR]

A proper increase of d -spacing after crosslinking is an effective strategy to enhance gas separation performance and anti-plasticization property of polymeric membranes. One way to achieve high chain distance is to design and prepare polymer precursors that have large side groups with crosslinkable functionality. Our previous research proved that the decarboxylation crosslinked polyimides connected by a biphenyl group showed enlarged d -spacing. However, the 100% crosslinking temperature is 425–450 °C that is higher than the glass transition temperature ( T g ) of most polymers and may cause problem for preparing asymmetric crosslink membranes. Here we proposed a thermal oxidative crosslinking method which had a lower crosslinking temperature than the decarboxylation crosslinking method. Specifically, we synthesized two phenolphthalein-based cardo diamines, MPP and PP, with or without CH 3 substituted groups and prepared the 6FDA-MPP and 6FDA-PP polyimides. The lactone ring in the cardo moiety decomposed and the crosslinking reaction took place by heating the polymer in an air purge atmosphere. A 100% conversion of the crosslinking reaction was obtained at 400 °C. In addition, the crosslinked polyimides showed increased d -spacing, high CO 2 permeability and CO 2 /CH 4 selectivity than before. The best result for pure gas test was achieved for 6FDA-MPP-400, which had a CO 2 permeability of 193.8 Barrer with a CO 2 /CH 4 ideal selectivity of 39.2. No plasticization was observed for the 6FDA-MPP-400 and 6FDA-PP-400 polyimides at a CO 2 pressure up to 450 psia. In addition, both 6FDA-MPP-400 and 6FDA-PP-400 showed excellent mixed gas selectivity of 35 at a partial CO 2 pressure of 147 psia. [ABSTRACT FROM AUTHOR]

A borrowing-hydrogen reaction between amines and alcohols is an atom-economic way to prepare alkylamines, ideally with water as the sole byproduct. Herein, nickel catalysts are used for direct N-alkylation of hydrazides and arylamines using racemic alcohols. Moreover, a nickel catalyst of ( S)-binapine was used for an asymmetric N-alkylation of benzohydrazide with racemic benzylic alcohols. [ABSTRACT FROM AUTHOR]

A borrowing-hydrogen reaction between amines and alcohols is an atom-economic way to prepare alkylamines, ideally with water as the sole byproduct. Herein, nickel catalysts are used for direct N-alkylation of hydrazides and arylamines using racemic alcohols. Moreover, a nickel catalyst of ( S)-binapine was used for an asymmetric N-alkylation of benzohydrazide with racemic benzylic alcohols. [ABSTRACT FROM AUTHOR]

The effect of solution annealing on the microstructure evolution and pitting corrosion resistance of SAF2906 super duplex stainless steel has been investigated. The samples are solution treated from 850 to 1100 °C for 30 min and then water quenched to room temperature. The results show that static recrystallization preferentially occurs within the δ ferrite phase at 900 °C, and the static recrystallization of the ferrite and austenite phases is completed at 1050 °C. When samples aere exposed to higher temperatures, the grain of the ferrite and austenite does not seem to coarsen. Inappropriate annealing at temperatures below 1050 °C inevitably lead to many secondary phases, which are characterized by transmission electron microscopy to be Cr2N and the σ phase. With an increase in the solution temperature, the σ phase dissolved into the matrix before Cr2N, and as the temperature reached 1050 °C, no secondary phases can be observed by scanning electron microscopy. The pitting corrosion resistance of the samples after solution annealing is determined by anodic polarization tests. The electrochemical results show that the σ phase and Cr2N decreased the pitting corrosion resistance and that the σ phase had a more significant effect on the corrosion resistance compared with Cr2N. [ABSTRACT FROM AUTHOR]

The development of a bio-based plasticizer with good plasticizing performance, migration resistance, and thermal stability for polyvinyl chloride (PVC) is still a notable challenge due to the trade-off between molecular weight and compatibility. Herein, epoxidized isosorbide-based esters featuring multiple epoxy groups were prepared via the esterification of isosorbide with various aliphatic acids with C-18 alkyl chains (oleic acid, linoleic acid, and linolenic acid) followed by epoxidation. The resulting epoxidized isosorbide-based esters were utilized as PVC resin plasticizers, and the overall performance of these plasticized PVC specimens was investigated in detail. Moreover, the esterification reaction was optimized and 1-propylsulfonic-3-methylimidazolium hydrogensulfate ionic liquid was selected as the catalyst. After the reaction was complete, the ionic liquid and product were in separate phases, enabling facile catalyst recycling in a simple, convenient, and environmentally friendly process. The most superior plasticizing effect was achieved by epoxidized isosorbide linolenate (EGLA-ISB). In comparison to the PVC samples plasticized with dioctyl terephthalate (DOTP), those plasticized with EGLA-ISB demonstrated a 15-fold increase in thermal stability during isothermal testing (a PVC/50EGLA-ISB film had a low weight loss of approximately 1.5% after heating at 200 °C for 120 min). Furthermore, the initial thermal decomposition temperature of the PVC plasticized by EGLA-ISB increased by almost 40 °C (up to 306.9 °C) compared to pure PVC, and a higher elongation at break (387%) was also observed. The excellent performance of the PVC plasticized by EGLA-ISB was attributed to the C-18 alkyl chains and multiple epoxy groups of EGLA-ISB, which improved its PVC compatibility, enhanced the thermal stability of the PVC. [Display omitted] • EGLA-ISB was prepared via the esterification of isosorbide with linolenic acid and followed by epoxidation. • 1-Propylsulfo-3-methylimidazolium hydrogen sulfate ionic liquid was chosen as the catalyst for the esterification reaction. • After the reaction was complete, the ionic liquid and product were in separate phases, enabling facile catalyst recycling. • PVC/50EGLA-ISB film has a low weight loss of approximately 1.5% after heating at 200 °C for 120 min. • EGLA-ISB avoids the trade-off between molecular weight and compatibility. [ABSTRACT FROM AUTHOR]

Ion transport plays an important role in various biological processes because of the ability of ions to move rapidly in biological ion channel‐confined spaces. For example, rapid proton transport in ATPases is attributed to confined channel spaces and conjugated sites. According to molecular dynamics simulations, the confined spaces and conjugated sites in nanochannels can enhance ion transport. Herein, it is demonstrated that the ATPase‐like structures of sulfonic acid‐modified covalent organic framework nanochannels, which promote the formation of highly ordered and continuous water molecular chains and confined spaces, can support ion (H+, Li+, Na+, and K+) transport rates that are an order of magnitude higher than those of bulk water. The ion transport rates in the nanochannel are superior to those in other artificial channels. Moreover, the selectivity of cations in the nanochannel is evaluated using the diffusion potential with a concentration gradient. The simulations and experimental results demonstrate that confined spaces and conjugated sites are crucial for efficient ion transport in nanochannels modified by sulfonic acid groups as cation conductor materials. [ABSTRACT FROM AUTHOR]

The spoilage potential of Shewanella putrefaciens and S. baltica isolated from spoiled refrigerated Litopenaeus vannamei was evaluated by in vitro assays for trimethylamine oxide reduction, extracellular hydrolytic enzymes and biofilm formation, and in vivo inoculation into surface-sterilised shrimp followed by microbial, biochemical and sensory analyses during storage for 5 days at 4 °C. S. baltica displayed higher spoilage potential than S. putrefaciens both in vitro and in vivo. Shrimp co-inoculated with them had one-day shorter shelf life than those mono-inoculated, based on the results of bacterial density, volatile base nitrogen, trimethylamine, volatile organic compounds and sensory analysis, which strongly suggests cooperation of Shewanella species in shrimp spoilage. Exogenous cyclo-(L-Pro-L-Leu) boosted bacterial growth, extracellular protease and collagenase activities, and biofilm formation of S. putrefaciens and S. baltica at least before they entered the stationary phase, indicating that cyclo-(L-Pro-L-Leu)-dependent quorum sensing, a recently suggested communication mechanism between them, contributes to the cooperation. [ABSTRACT FROM AUTHOR]

Three spirobichroman-based diamines, FSBC, SBC and MSBC, with different substituted groups (-CF 3, -H, and -CH 3 ) were synthesized. The diamines were reacted with 4,4′-hexafluoroisopropylidene bisphthalic dianhydride (6FDA) to form 6FDA-FSBC, 6FDA-SBC, and 6FDA-MSBC polyimides, respectively. The organosolubilities, molecular weights ( M n ), densities, glass transition temperature (T g ), thermal stabilities, fractional free volume (FFV), d -spacing and gas separation properties of the spirobichroman-based polyimides were systematically studied. The three spirobichroman-based polyimides had high M n and T g , excellent thermal stabilities, and good solubilities in a wide range of organic solvents. 6FDA-FSBC exhibited the highest gas permeability which could be attributed to its insufficient chain packing conditions rooting from the incorporation of spriobichroman backbone with the spiro and non-coplaner nature, and the bulky CF 3 substituting group that increased the polymer FFV and decreased the polymer chain flexibility. 6FDA-MSBC had the highest H 2 /CH 4 selectivity due to the present of the CH 3 group in the diamine moiety which had the turnstile-like rotary thermal motion that inhibited the diffusion of large molecules like CH 4 but had little effect on the diffusion of small molecules like H 2 . [ABSTRACT FROM AUTHOR]

Two carboxylic acid containing diamines, CADA1 and CADA2, with or without bulky CF 3 group were synthesized and polymerized with 6FDA, BTDA and DSDA to form four polyimides, denoted as 6FDA-CADA1, 6FDA-CADA2, BTDA-CADA1 and DSDA-CADA1. After the thermal induced decarboxylation crosslink reaction, polyimides with 100 times’ higher CO 2 permeabilities, similar CO 2 /CH 4 selectivities and much better plasticization resistant properties were obtained compared with the un-crosslinked polyimides. The polymer d-spacing increased with the heating temperature and those of the fully crosslinked polyimides, 6FDA-CADA1-450 and DSDA-CADA1-450, were 5.81 Å and 5.51 Å, respectively, which were very close to the estimated distance between the crosslinked polymer chains (5.57 Å, calculated by Material Studio). The CO 2 -induced plasticization phenomenon was not observed at a CO 2 pressure up to 30 atm for polyimides after thermally treated at temperatures above 425 °C. Moreover, polyimides crosslinked at different temperatures had almost the same selectivities, but their permeabilities gradually increased with the crosslinking temperature. For CO 2 /CH 4 gas pair, the separation performances of 6FDA-CADA1-425 and BTDA-CADA1-450 membranes surpassed the “2008 Robeson Upper Bound”, and other membranes thermally treated at 400 and 425 °C were all positioned near the “1991 Robeson Upper Bound”. [ABSTRACT FROM AUTHOR]

Fish skin has both positive and negative effects on the shelf-life of the fish. This study aimed to investigate the spoilage process of the skin and flesh of refrigerated farmed turbot ( Scophthalmus maximus) with vacuum packaging. Microbial community changes were analyzed by combining culture-dependent and culture-independent methods. The results indicated that the shelf-life of vacuum-packaged refrigerated turbot was 16 d; skin mucus was the interference factor of turbot quality. The culture-dependent analysis demonstrated that the total viable counts and the population of H2S-producing bacteria, Pseudomonas spp., Enterobacteriaceae spp., and lactic acid bacteria in skin had a range of 0.45 to 1.40 log (CFU/g) higher than the microbial numbers in flesh after 16 d in storage. 16S high throughout sequencing results demonstrated that the compositions of spoilage microbes were similar in skin and flesh. Shewanella spp., followed by Carnobacterium spp., was the dominant spoilage organism at day 16. Quorum sensing (QS) signaling activity increased during the storage. Exogenous N-butanoyl-L-homoserinelactone(C4-HSL) and N-hexanoyl-Lhomoserine lactone (C6-HSL) significantly accelerated the spoilage process of refrigerated turbot, while the addition of 4, 5-Dihydroxypentane-2, 3-dione (DPD) prolonged the lag phase duration. Therefore, QS may be involved in the spoilage process of refrigerated turbot. [ABSTRACT FROM AUTHOR]

Thermal oxidative crosslinking results in the generation of oxygen bridges among polymer chains and helps regulate the membrane microstructure. Simultaneously, any strategy to increase the crosslinking sites of polyimide (PI) can improve the crosslinking efficiency and allow precise control of the pore structure of membranes. Phenolphthalein-based PIs are potentially suitable precursors for thermal oxidative crosslinking of membranes, since thermal treatment will result in the degradation of lactone ring leading to the generation of a pair of phenyl crosslinking sites. In this work, three phenolphthalein-based diamines with different structures were designed and synthesized. The three diamines were subsequently reacted with 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA) to prepare phenolphthalein-based PIs. The original membranes were post-treated by thermal oxidation crosslinking at 400 °C and 425 °C, respectively; the lactone ring underwent decomposition, and the imide ring opened at the same time, resulting in the generation of multiple crosslinking sites and correspondingly improving the crosslinking efficiency. The effect of the side groups (−CH 3 , –CF 3 or unsubstituted) of phenolphthalein-based diamine and thermal treatment temperatures on the gas separation performance of phenolphthalein-based PI membranes were investigated. Wide-angle X-ray diffractometry (WAXD) and wide-angle X-ray scattering (WAXS) analysis demonstrated that the π-π stacking distance were improved. BTDA-FPP-425 had a CO 2 /CH 4 selectivity of 37.68. This thermal degradation along with thermal oxidative crosslinking strategy provides a promising approach for fabrication of CO 2 /CH 4 separation membrane. [Display omitted] • Phenolphthalein-based polyimide is a suitable precursor for thermal crosslinking. • BTDA-based polyimide has low cost and good mechanical properties. • The lactone ring and the imide ring open, generating multiple crosslinking sites. • Thermal degradation and oxidative crosslinking improved the π-π stacking values. • A strategy for making CO 2 /CH 4 separation membrane with anti-plastic was achieved. [ABSTRACT FROM AUTHOR]

A novel strategy was employed to introduce a carbon layer on Si particle to overcome the intrinsic poor electrical conductivity and significant volume change. The carbon layer was fabricated by forming polyphosphazene coating through a facile precipitation polymerization method, followed by carbonization. As a result of formation of core-shell structure, the Si anode exhibited improved cycling stability (740 mA h/g remained after 100 cycles) and rate capability (300 mA h/g at a rate 2C). In addition, 99% coulombic efficiency was remained after 100 cycles. [ABSTRACT FROM AUTHOR]

Carboxylated PIM-1 fibers were prepared by one-step hydrolysis of PIM-1 fibers using sodium hydroxide solution. The chemical structure and morphology of the hydrolyzed PIM-1 fibers were characterized. The adsorption behaviors of the hydrolyzed PIM-1 fibers towards different organic dyes and heavy metal ions in an aqueous solution were investigated. The results showed that the hydrolyzed PIM-1 fibers could effectively adsorb methylene blue (MB), safranin O (SO), and methylene violet (MV), but barely adsorb methyl orange (MO), indicating a selective adsorption property. Isotherm studies revealed that the Freundlich model was more suitable for describing the adsorption behavior of the hydrolyzed PIM-1 fibers than the Langmuir model. The adsorption mechanism was investigated by UV–vis absorbance spectra and solution pH effect. It was concluded that the adsorption process was based on the host–guest interactions between the hydrolyzed PIM-1 fibers and the dyes. In addition, the hydrolyzed PIM-1 fibers exhibited an improved adsorption capacity for heavy metal ions (41.2 mg/g for Pb 2+ , 16.9 mg/g for Cu 2+ , respectively) than the pristine PIM-1 fibers. Based on our results, the hydrolyzed PIM-1 fibers, as an easily prepared adsorbent material, show potential application for the selective removal of various organic dyes and heavy metal ions in wastewater treatment. [ABSTRACT FROM AUTHOR]

This study investigated the segregation behavior of alloying additives X (X = Si, Al, V, Ti, Mo, W, Nb, Y) on the Fe(1 1 1)/Cr 2 O 3 (0 0 0 1) interface as well as the effects of these additives on the interfacial adhesive strength by using the first-principles method. The results indicated that W, Mo, and Nb atoms were easily segregated at the Fe(1 1 1)/Cr 2 O 3 (0 0 0 1) interface, however, the introduction of them would weaken the adhesive strength of the interface through weak-electron effects. Moreover, Y, Al, Si, Ti, and V were difficult to segregate at the Fe(1 1 1)/Cr 2 O 3 (0 0 0 1) interface. Comparison of separation energies and interfacial structural properties suggested that introduction of Si and Al improved the adhesive strength of the Fe(1 1 1)/Cr 2 O 3 (0 0 0 1) interface through strong interactions between Si/Al and O. Thus, Si and Al improved the adhesion of surface oxide scales and enhanced oxidation resistance. [ABSTRACT FROM AUTHOR]

At present, people's environmental awareness gradually enhances, and the environmental requirements on production and living continuously improve. Urban sewage discharge management and sewage treatment intensity are increasing in whole country, and urban water environment has certain improvement. But in rural areas, due to relatively weak environmental awareness of residents, not high economic development degree and not perfect infrastructure construction, the issue has not been handled properly. It seriously restricts further development of rural economy, and contradiction between water pollution worsening and farmers eager to raise the level of living environment increasingly aggravating has become key problem restricting China's new rural construction. According to status quo of rural water pollution in China, causes and hazards of rural water pollution are analyzed in detail, and several treatment suggestions are put forward. [ABSTRACT FROM AUTHOR]

Background: 5-Hydroxytryptamine (5-HT) and stem cells marker G-protein-coupled receptor 5 (LGR5) are associate with gastrointestinal inflammation and tumorigenesis. But the relationship between 5-HT and LGR5 is unclear. Objective: To explore the expression and correlation of 5-HT and LGR5 in gastric mucosa of patients with gastritis and gastric cancer (GC). Methods: A total of 41 patients with GC and 98 patients with chronic gastritis were included in this study. The expression of TPH1 mRNA, LGR5 mRNA and β-catenin mRNA in gastric mucosa were explored by Real-time Quantitative polymerase chain reaction (qPCR). 5-HT-positive cells and LGR5-positive cells in gastric mucosa were detected by immunohistochemistry stains. The co-localization of 5-HT and chromogranin A (CgA), 5-HT receptor4 (5-HTR4) and LGR5 were detected by multiplex immunofluorescence. Results: The expression of 5-HT and LGR5 in patients with GC was significantly higher than patients with chronic gastritis (p < 0.05). The positive rate of 5-HT and LGR5 increased sequentially in the patients with non-atrophic gastritis, intestinal metaplasia and GC, which were 18.52%, 35.56% and 75.61% for 5-HT, and 27.78%, 40.91% and 95.12% for LGR5, respectively. The expression of 5-HT and LGR5 was positively correlated in gastritis and GC patients (p < 0.05). Moreover, the expression level of TPH1 mRNA and LGR5 mRNA was also positively correlated in gastritis patients (r = 0.7377, p < 0.001). Besides, 5-HT was partially co-localized with CgA, and 5-HTR4 was co-localized with LGR5 in gastric mucosa. Conclusion: The increase of 5-HT synthesis in gastric mucosa may have an impact on LGR5-positive gastric epithelial stem cells. [ABSTRACT FROM AUTHOR]

Highlights: [•] The dissolution and diffusion properties of S in Ni were studied under the applied stress. [•] S diffusion is accelerated under the applied tensile stress. [•] Under the applied tensile stress, the structure of the Ni–S system became more stable. [•] The dissolved S has a tendency of precipitating from the Ni matrix. [ABSTRACT FROM AUTHOR]

Poly(butylene adipate-co-terephthalate) (PBAT) is a biodegradable polymer synthesized from petrochemical resources. PBAT has an exceptionally high elongation at break values which makes it one of the most promising substitutes for LDPE packaging films. However, the applicability of PBAT films is still limited by low strength and high production costs. In this work, we used polyethylene glycol 600 (PEG-600) as a coating agent to modify the surface of calcium carbonate and improve compatibility with the polymer matrix. A series of PBAT/CaCO3 composite films having different CaCO3 particle size and content of coating agent was prepared using extrusion blow molding. The effect of particle size of CaCO3 filler and the content of a coating agent on the mechanical and rheological properties of composite films have been studied. The biodegradation properties have been tested by burying the samples in soil or keeping them in artificial seawater for 90 days. It was shown that the addition of PEG-600 improves compatibility between the matrix and CaCO3 filler as polar –OH groups of PEG have a high affinity toward the polar surface of CaCO3. Moreover, the hydrophilicity of PEG-600 increased the diffusivity of water molecules and facilitated PBAT degradation. This work provides experimental data and theoretical guidance that support the development of high-performance PBAT/calcium carbonate films for the single use packaging industry. [ABSTRACT FROM AUTHOR]

In Mg-Li-Al alloys, θ-phase MgAlLi is a strengthening and metastable phase which is liable to be transformed to the equilibrium phase AlLi on overaging. While the structural details of the θ-phase MgAlLi and the microscopic transformation are still unknown. In this paper, the structure of MgAlLi unit cell was determined through X-ray powder diffraction simulation. Microscopic transformation process of θ-phase MgAlLi was discussed in detail using first principles method. [ABSTRACT FROM AUTHOR]

Abstract: A nano TiO2 film was coated on AZ31 alloy substrate by sol–gel method. The TiO2 film was characterized by X-ray diffractometry (XRD), differential scanning calorimetry-thermogravimetric analysis (DSC-TG), field emission scanning electron microscopy (FE-SEM) and energy dispersion spectroscopy (EDS). The degradation of the nano-TiO2 coated alloy was evaluated by immersion test and electrochemical measurement. An attempt was made to relate corrosion of coated alloys with the annealing treatment and resultant structural evolution. [Copyright &y& Elsevier]

Polymer/clay composites are an innovative class of materials. In this study, we present a facile method for the preparation of biodegradable and robust PLA/organomodified montmorillonite (OMMT) composite films with excellent gas barrier performance. When the design of PLA/OMMT composite films, in addition to making OMMT have good intercalation effect in the matrix, the compatibility of intercalating polymer and matrix should also be considered. In this work, two polymers with high gas barrier properties, namely poly(vinyl alcohol) (PVA) and ethylene vinyl alcohol copolymer (EVOH), were selected to intercalate OMMT. The morphology and microstructures of the prepared PLA/PVA/OMMT and PLA/EVOH/OMMT composites were characterized by the X-ray diffraction measurement, scanning electron microscopy, and differential scanning calorimetry. It was shown that the good dispersibility of PVA in the PLA matrix, rather than the intercalation effect, was responsible for the improved gas barrier and mechanical properties of PLA/PVA/OMMT composite. The elongation at break increases from 4.5% to 22.7% when 1 wt % PVA is added to PLA/OMMT. Moreover, gas barrier of PLA/PVA1/OMMT measured as O2 permeability is 52.8% higher than that of neat PLA. This work provides a route to intercalate OMMT interlayer with high gas barrier polymers and thus can be a useful reference to fabricate PLA/OMMT composites with improved gas barrier and mechanical properties. A comparison of oxygen permeabilities with existing commercial packaging films indicates that the biodegradable PLA/PVA/OMMT may serve as a viable substitute for packaging film applications. [ABSTRACT FROM AUTHOR]

"Green" alternatives for petroleum-derived engineering plastics, like poly(ethylene terephthalate) (PET), include polyesters synthesized from 2,5-furan-dicarboxylic acid (FDCA). FDCA-based polyesters attracted a lot of attention from scientists and engineers because of their excellent gas barrier properties. This work analyzed, theoretically and experimentally, the transport properties of oxygen and carbon dioxide in amorphous poly(ethylene 2,5-furandicarboxylate) (PEF), poly(propylene 2,5-furandicarboxylate) (PPF) and poly(butylene 2,5-furandicarboxylate) (PBF) films. Molecular simulations studied the effect of the furan-based polyesters containing different amounts of methylene on the films' gas transport performance and other properties. The adsorption capacity and active sites in the films were assessed using the Grand Canonical Monte Carlo (GCMC) method. The gas molecule diffusion through the films was analyzed by the molecular dynamics approach. The permeability of three polymers are extremely low. Specifically, PEF and PPF showed almost no difference in their gas permeability. However, as the methylene groups amount increased to 4 (in PBF), the oxygen permeability increased significantly while barely any changes in CO 2 were observed. We also prepared furan-based polyester films to experimentally assess their permeation performance, which agreed with the results obtained by simulations. This work provided some insights into the permeability and formation mechanisms of these films. In particular, the non-linear axis of ring rotation coupled with the dipolarity of the heterocycle in furan-base polyesters significantly hinders its furan ring-flipping. This feature is favorable in advancing furan-based polyesters as novel materials for food packaging applications. [Display omitted] •O 2 and CO 2 permeabilities in PEF and PPF were very similar. • For PBF, the O 2 permeability increased while the CO 2 permeability did not change significantly compared to PEF and PPF. • The low rotational activity, as well as the polarity and the steric asymmetry, restrict the furan ring flipping. • The presence of C−H⋯O hydrogen bonds also enables the furan-based polyesters with excellent gas barrier properties. [ABSTRACT FROM AUTHOR]

Post-modification of the chemical structures can be used to tailor the properties of polymers of intrinsic microporosity (PIM-1), which shows promise for application of PIM-1 gas separation membrane. Methane sulfonic acid (MSA) is capable of hydrolyzing and crosslinking nitrile groups of PIM-1 to form carboxylic acid-contained and triazine groups crosslinked PIM-1 (cPIM-1), and simultaneously catalyze in situ synthesis of porous polymer networks (PPNs) in PIM-1 matrix. These reactions were carried out at the same time by a one-step method. Characterization of hydrolysis and crosslinking process of nitrile groups in PIM-1 was performed by ATR, XPS, solubility, and 1H NMR analysis. MSA catalyzed synthetic approach of PPNs includes the trimerization of three acetyl groups and involves a coupled process of polymerization and membrane architecture formation. Finally, the process of crosslinking and hydrolysis can provide enhanced gas pair selectivity of PIM-1 membrane (cPIM-1) while the gas permeability of the membranes (cPIM-1/PPNs) can be increased by the incorporation of PPNs microstructure networks. As a result, the optimal cPIM-1/PPNs showed Roberson's 2008 upper bound separation performance for CO 2 /CH 4 and CO 2 /N 2. The cPIM-1/PPN2-3% membrane demonstrated the best CO 2 comprehensive separation performance with the permeability of almost 11511 Barrer, with ideal selectivity of 24.3 and 22.2 for CO 2 /N 2 and CO 2 /CH 4 respectively. Furthermore, the cPIM-1/PPNs membranes show excellent anti-aging properties. This indicates that MSA-catalyzed hydrolysis, crosslinking and in situ synthesis PPNs can effectively adjust the topological structure of PIM-1 membrane for CO 2 separation. [Display omitted] • Methane sulfonic acid (MSA) is capable of hydrolyzing and crosslinking nitrile groups of PIM-1 to form carboxylic acid-contained and triazine groups crosslinked cPIM-1. • Simultaneously, MSA can catalyze in situ synthesis of porous polymer networks (PPNs) in PIM-1 matrix. • The process of crosslinking and hydrolysis can provide enhanced gas pair selectivity of cPIM-1. • The gas permeability of cPIM-1/PPNs membranes can be increased by the incorporation of PPNs microstructure networks. [ABSTRACT FROM AUTHOR]

Poly(butylene adipate-co-terephthalate) (PBAT) is considered as the most promising polymers for preparing biodegradable mulching films. However, PBAT films are suffered to severe weathering in use. This study aims to look into the effects of high amounts of micro-sized calcium carbonate and silane coated calcium carbonate on the weathering of PBAT films, as well as the effects of photooxidative degradation and hydrolysis on the weathering performance of neat PBAT and composite films. The effects of two different artificial weathering processes, namely only UV irradiation (dry condition) and UV irradiation + water spray condition, on the degradation rate of neat PBAT and its composite films were evaluated to distinguish the influences of photooxidative degradation and hydrolysis on the weathering of PBAT films. The results indicated that neat PBAT film had the fastest degradation rate under two different weathering conditions. After adding calcium carbonate, the degradation rate was delayed due to the shading effect of calcium carbonate. Comparing two different weathering conditions, it was found that degradation rates of PBAT in water spray conditions were higher than in dry conditions due to accelerated degradation rate via hydrolysis. However, in the water spray condition, the mechanical characteristics of the films containing silane-coated calcium carbonate degraded more slowly than in the dry condition. Although hydrolysis reaction accelerates the molecular weight reduction rate of PBAT, at the same time, silane molecules self-crosslink to form a three-dimensional network in the presence of water, thus compensating for the loss of mechanical properties of PBAT matrix caused by the decrease of molecular weight. [Display omitted] • The degradation rate of PBAT is delayed in PBAT/CaCO 3 films due to the shading effect of CaCO 3. • The degradation rate of PBAT is higher under water spraying conditions than under dry conditions. • The cross-linking reaction of silanes will form network structures which can improve the mechanical strength of the film. [ABSTRACT FROM AUTHOR]

The dependence of the local field enhancement in gold nanoshells was investigated as a function of the core and embedding medium dielectric constant. Numerical calculations based on quasistatic theory indicated two local field factor peaks. If the core dielectric constant is a fixed value and the dielectric constant of surrounding medium is increased from 1.0 to 6.0, the shorter wavelength peak redshifts and decreases nonlinearly, whereas the longer wavelength peak redshifts, increases first and then decreases. On the contrary, if the surrounding dielectric constant is a fixed value and the core dielectric constant is increased from 1.0 to 6.0, the shorter wavelength peak redshifts and increases nonlinearly, whereas the longer wavelength peak redshifts and decreases nonlinearly. [ABSTRACT FROM AUTHOR]

In this research work, both natural weathering and artificial weathering processes were carried out to investigate the effects of multi-functional epoxy chain extender (Joncryl ADR 4370) content on the degradation and the mechanical properties and molecular weight of poly(butylene adipate- co -terephthalate) (PBAT). The carboxyl end-groups of PBAT decreased significantly with an increase in ADR content from 0 to 1.5 wt%. Similarly, the molecular weight of PBAT initially increased and then decreased because of the formation of a crosslinked network structure under the influence of excessive chain extenders. The main degradation mechanism of PBAT during the natural and artificial weathering process is photo-degradation and hydrolyzation. The degradation rate of PBAT increased with increasing content of chain extender, as hydroxyl groups facilitate the water attack on the ester bonds of PBAT. In contrast, the higher content of chain extender presented the lower loss velocity of the tensile strength. This is mainly because the more ADR content, the more crosslinking network structures will be formed during the melting extrusion which can slow down the decrease of tensile strength. Hence, it is indicated that the crosslinking structure has more effect on tensile strength than that of hydrolysis effect during degradation. According to the analysis and study on the performance changes of PBAT/ADR materials under the conditions of long-term natural weathering (360d) and artificial weathering (600 h), this work provides theoretical guidance to produce PBAT mulching films with excellent performance. [Display omitted] •Effect of chain extender and its content on weathering resistance of the PBAT. •The main degradation mechanism of PBAT during weathering process is photo-degradation and hydrolyzation. •The higher content of chain extender presents the lower loss velocity of the PBAT tensile strength. •This work provides theoretical guidance to produce PBAT mulching films with excellent performance. [ABSTRACT FROM AUTHOR]

The effect of boron (B) on stress corrosion resistance of S31254 in the presence of residual stresses has been studied. The microstructure and corrosion resistance of S31254 containing B at different levels of cold deformation are analyzed in this study. In the results, it is shown that B favors the improvement of deformation uniformity of S31254. The grain boundary (GB) and slip bands have better corrosion resistance at 5% deformation, and the overall corrosion resistance is better than that of the undeformed state, with smaller passivation current density and narrower width of GB corrosion grooves, especially for the 40B samples. At 30% deformation, the overall corrosion resistance of 40B S31254 is better than 0B due to improved deformation uniformity. [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) is the prevailing raw material for fused deposition modeling (FDM) 3D printing filaments, offering benefits such as a low printing temperature, minimal shrinkage, and biodegradability. However, this material has challenges such as poor toughness, low heat deflection temperature, susceptibility to moisture‐induced thermal degradation, and high costs. This study addressed these concerns by incorporating natural bamboo fiber (BF) into PLA, elevating heat the deflection temperature and lowering the material costs. Additionally, a synthesized branched structure compatibilizer, in the form of epoxidized soybean oil‐branched cardanol ether (ESOn‐ECD), enhanced the toughness of PLA, the bonding strength between PLA and the BF surface, and the flowability of high‐fiber composites during processing and printing. The mechanical, thermal, and rheological properties were assessed, demonstrating the promising processing performance of PLA/BF/ESO3‐ECD. The fully biobased composite exhibits strength, toughness, good processability, excellent 3D printability, and durability, implying substantial potential in FDM 3D filament production. Highlights: Bio‐based PLA/bamboo fiber/ESO3‐ECD FDM 3D printing filaments were developed.The excellent nucleation ability of the bamboo fibers enhances the crystallization rate and crystallinity of PLA.The epoxy values and branching degree of ESOn‐ECD are crucial for its effective modification. [ABSTRACT FROM AUTHOR]

Aiming to address the Mo volatilization problem of super-austenitic stainless steel at high temperature, the S31254 steel containing B and rare earth element Y with high oxidation resistance was designed. It was observed that a synergy of B + Y can promote the formation of the dense Cr2O3 layer at 1050 and 1100 °C, making MoO3 layer formation difficult. While the oxide layers of the 0B sample from top to bottom were divided into four layers: Fe-rich oxide layer, MoO3 layer, Cr–Mn–Ni spinel oxide layer, and Cr2O3 layer (loose and porous), thus the undense Cr2O3 layer in the 0B sample can hardly inhibit MoO3 volatilization, especially at 1100 °C. In addition, the synergistic effect of B and Y on the diffusion of Cr to the surface was calculated using first-principles calculations. The results demonstrated that both the addition of B and Y can enhance Cr diffusion to the surface, while Y can specifically promote the combination of Cr and O. Consequently, the combined presence of B and Y exhibits a more favorable synergy for improving the density of the Cr2O3 layer, effectively inhibiting MoO3 formation and volatilization, thereby enhancing the oxidation resistance of S31254. [ABSTRACT FROM AUTHOR]

With the popularity of portable positioning devices, crowd-sourced trajectory data have attracted widespread attention, and led to many research breakthroughs in the field of road network extraction. However, it is still a challenging task to detect the road networks of old downtown areas with complex network layouts from high noise, low frequency, and uneven distribution trajectories. Therefore, this paper focuses on the old downtown area and provides a novel intersection-first approach to generate road networks based on low quality, crowd-sourced vehicle trajectories. For intersection detection, virtual representative points with distance constraints are detected, and the clustering by fast search and find of density peaks (CFDP) algorithm is introduced to overcome low frequency features of trajectories, and improve the positioning accuracy of intersections. For link extraction, an identification strategy based on the Delaunay triangulation network is developed to quickly filter out false links between large-scale intersections. In order to alleviate the curse of sparse and uneven data distribution, an adaptive link-fitting scheme, considering feature differences, is further designed to derive link centerlines. The experiment results show that the method proposed in this paper preforms remarkably better in both intersection detection and road network generation for old downtown areas. [ABSTRACT FROM AUTHOR]

Graphene oxide(GO)/polylactic acid (PLA) nanocomposite, prepared using a solvent-free melt mixing processing, is investigated as a potential oxygen barrier packaging film in this work. In order to disperse GO homogeneously in PLA matrix, hydrophobic silane coupling agent, i.e., γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560), is used to modify the graphene oxide sheets. The modified GO is able to be well bonded to the PLA due to the formation of covalent bonds between the epoxy groups of KH560 and the carboxyl and hydroxyl terminal groups of PLA. Furthermore, the thermal stability of GO is enhanced due to the long alkyl side chain of KH560, which could also increase the crystallinity of PLA. As a result, the crystallinity of PLA is significantly improved because of the linear KH560 chains, which can act as nucleating agents to improve the crystallization. The KH560-GO helps to reduce the O2 permeability of KH560-GO/PLA composite films via a dual-action mechanism: (1) providing physical barrier due to their native barrier properties, and (2) by resulting in higher degree of crystallinity. The as-prepared KH560-GO0.75/PLA is able to exhibit ca. 33% and ca. 13% decrease in the PO2 than the neat PLA and GO0.75/PLA film, respectively. Finally, the mechanical properties and impact fractured surfaces indicate that the increase in the tensile strength and elongation at break value of KH560-GO/PLA are due to the strong interfacial adhesion and the strong bonding between the epoxy group of KH560-GO and hydroxyl and carboxyl acid terminal groups of PLA matrix. [ABSTRACT FROM AUTHOR]

With the help of the nonequilibrium Green's function technique, we theoretically analyze the thermospin property through a typical T-shaped spin valve with spin-flip scattering in the linear regime. The influences of spin-flip coefficient of interdot λ , spin-flip coefficient of intradot η and interdot hopping coefficient t + δ σ Δ t on thermospin property are discussed. As interdot hopping coefficient t is equal to energy level ε , the spectrum of G s shows Fano-like effect with ε variation. Antiresonance position of G s is almost unchanged and its width becomes narrower with ε increasing. Spin thermopower S s is close to the maximum of the peak and charge thermopower S c is equal to zero for t = ε. As a result, the pure spin thermopower S s can be obtained, which means that a pure spin current may be produced by a temperature gradient in our system. It is found that spin figure of merit Z T s can reach a considerable value by adjusting key parameters of the system, such as Δ t , β , α , ϕ. The typical T-shaped spin valve can be treated as a stable thermospin battery which allows to convert the heat energy to spin voltage, thus produces the pure spin current in the device. • We derive the expressions of the thermoelectric coefficients by means of the nonequilibrium Green function. • The influences of spin-flip scattering on thermospin property are analyzed. • As interdot hopping coefficient t is equal to energy level ε , the spectrum of Gs shows Fano-like effect with ε variation. • It is found that spin figure of merit ZTs can reach a considerable value by adjusting key parameters. • The typical T-shaped spin valve can be treated as a stable thermospin battery. [ABSTRACT FROM AUTHOR]

Extracting highly detailed and accurate road network information from crowd-sourced vehicle trajectory data, which has the advantages of being low cost and able to update fast, is a hot topic. With the rapid development of wireless transmission technology, spatial positioning technology, and the improvement of software and hardware computing ability, more and more researchers are focusing on the analysis of Global Positioning System (GPS) trajectories and the extraction of road information. Road intersections are an important component of roads, as they play a significant role in navigation and urban planning. Even though there have been many studies on this subject, it remains challenging to determine road intersections, especially for crowd-sourced vehicle trajectory data with lower accuracy, lower sampling frequency, and uneven distribution. Therefore, we provided a new intersection-first approach for road network generation based on low-frequency taxi trajectories. Firstly, road intersections from vector space and raster space were extracted respectively via using different methods; then, we presented an integrated identification strategy to fuse the intersection extraction results from different schemes to overcome the sparseness of vehicle trajectory sampling and its uneven distribution; finally, we adjusted road information, repaired fractured segments, and extracted the single/double direction information and the turning relationships of the road network based on the intersection results, to guarantee precise geometry and correct topology for the road networks. Compared with other methods, this method shows better results, both in terms of their visual inspections and quantitative comparisons. This approach can solve the problems mentioned above and ensure the integrity and accuracy of road intersections and road networks. Therefore, the proposed method provides a promising solution for enriching and updating navigable road networks and can be applied in intelligent transportation systems. [ABSTRACT FROM AUTHOR]