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• A total of 930 metabolites were identified in quinoa sprouts. • 232 metabolites responded significantly to saline-alkali stress. • Saline-alkali stress decreased the concentration of flavonoids and phenolic acids. • Different metabolites were mainly enriched in flavonoid and amino acid pathways. Quinoa sprouts are a green vegetable rich in bioactive chemicals, which have multiple health benefits. However, there is limited information on the overall metabolic profiles of quinoa sprouts and the metabolite changes caused by saline-alkali stress. Here, a UHPLC-MS/MS-based widely targeted metabolomics technique was performed to comprehensively evaluate the metabolic profiles of quinoa sprouts and characterize its metabolic response to saline-alkali stress. A total of 930 metabolites were identified of which 232 showed significant response to saline-alkali stress. The contents of lipids and amino acids were significantly increased, while the contents of flavonoids and phenolic acids were significantly reduced under saline-alkali stress. Moreover, the antioxidant activities of quinoa sprouts were significantly affected by saline-alkali stress. The enrichment analysis of the differentially accumulated metabolites revealed that flavonoid, amino acid and carbohydrate biosynthesis/metabolism pathways responded to saline-alkali stress. This study provided an important theoretical basis for evaluating the nutritional value of quinoa sprouts and the changes in metabolites in response to saline-alkali stress. [ABSTRACT FROM AUTHOR]

β- d -Glucopyranoside,(3β,12β,20E)-12,25-dihydroxydammar-20(22)-en-3-yl (pseudo-ginsenoside Rh2) and its 20Z-isomer were synthesized from ginsenoside Rh2 under a mild condition, via a simple three-step called acetylation, elimination–addition and saponification. In addition, their activities were evaluated by eight different human tumor cells, compared with ginsenoside Rh2 group. Results indicated that the reaction in the side chain might greatly enhance the anti-proliferative activity of ginsenosides. [ABSTRACT FROM AUTHOR]

Tartary buckwheat is rich in flavonoids, which not only play an important role in the plant-environment interaction, but are also beneficial to human health. Rutin is a therapeutic flavonol which is massively accumulated in Tartary buckwheat. It has been demonstrated that transcription factors control rutin biosynthesis. However, the transcriptional regulatory network of rutin is not fully clear. In this study, through transcriptome and target metabolomics, we validated the role of FtMYB102 and FtbHLH4 TFs at the different developmental stages of Tartary buckwheat. The elevated accumulation of rutin in the sprout appears to be closely associated with the expression of FtMYB102 and FtbHLH4. Yeast two-hybrid, transient luciferase activity and co-immunoprecipitation demonstrated that FtMYB102 and FtbHLH4 can interact and form a transcriptional complex. Moreover, yeast one-hybrid showed that both FtMYB102 and FtbHLH4 directly bind to the promoter of chalcone isomerase (CHI), and they can coordinately induce CHI expression as shown by transient luciferase activity assay. Finally, we transferred FtMYB102 and FtbHLH4 into the hairy roots of Tartary buckwheat and found that they both can promote the accumulation of rutin. Our results indicate that FtMYB102 and FtbHLH4 can form a transcriptional complex by inducing CHI expression to coordinately promote the accumulation of rutin. Tartary buckwheat is renowned for its high flavonoid content, particularly rutin. There are several new findings in this study: • We found that flavonoids, specifically rutin, were also abundant in sprout and seedling, and that the content decreased as the plant matured from sprout to seedling. • We discovered that two new transcription factors, FtMYB102 and FtbHLH4, can regulate rutin biosynthesis. • FtMYB102 and FtbHLH4 can interact with each other to form a transcriptional complex that regulates target genes expression. [ABSTRACT FROM AUTHOR]

In this work, phenolphthalin was successfully introduced into the molecule chain of poly(aryl ether nitrile) (PEN) by nucleophilic substitution method in order to get carboxylated PEN (PEN-COOH) copolymers with a controlled carboxylation degree. Then, a series of PEN-COOH ultrafiltration membranes were prepared by immersion precipitation phase inversion method. The influence of the carboxylation degree of PEN-COOH on the structure and performance of the prepared polymeric membrane was studied by scanning electron microscope, atomic force microscope, porosity, contact angle, ultrafiltration and antifouling experiments, etc. The results showed that with the increase of carboxylation degree of polymeric membrane, the surface of PEN-COOH membrane gradually became dense and smooth, and its hydrophilicity increased. Meanwhile, both the pure water flux and permeation flux of the membrane decreased obviously, and the corresponding rejection ratio of bovine serum albumin (BSA) was slightly enhanced. Also, the membrane showed improvement in antifouling property. As the membrane with the best comprehensive performance, PEN-COOH-60% membrane had a BSA rejection ratio as high as 99.3%, while maintaining water flux of 351.7 (L m−2 h−1) and permeation flux of 160.1 (L m−2 h−1). With a water contact angle of 59.7°, the flux recovery rate of PEN-COOH-60% membrane significantly increased 37.1% compared with PEN and basically stable in the three cycles of antifouling experiments. These results proved that the introduction of carboxyl group into PEN molecular chain could effectively improve the antifouling performance of PEN-COOH membrane. [Display omitted] • A series of PEN-COOH copolymers with different carboxylation degrees were synthesized as UF membrane materials. • In-depth study of the structure and performance of PEN-COOH membranes with different carboxylation degrees. • A more hydrophilic and smoother surface could be obtained by increasing the carboxylation degree of PEN membrane matrix. • PEN-COOH-60% membrane had the best overall membrane properties, while taking into account good antifouling durability. [ABSTRACT FROM AUTHOR]

To achieve the superheat-resistant polymers for flexible display substrates, two new diamines, namely 6-amine-2-(4-aminobenzene)-1-methyl-benzimidazole (m -MePABZ), 5-amine-2-(4-amino-benzene)-1-methyl-benzimidazole (p -MePABZ) containing N-methyl benzimidazole (BI) were synthesized and a serials of poly(benzimidazole imide) (PBII) films were prepared through thermal imidization. Among them, the flexible polyimide (PI) film derived from m -MePABZ and pyromellitic dianhydride (PMDA) has an ultra-low coefficient of thermal expansion (CTE) down to 2.5 ppm K−1 and an outstanding high glass-transition temperature (T g) up to 431 °C. Furthermore, the employment of N-methyl overcame an issue of the high H 2 O-absorption of traditional PBIIs, and the effect of " para -" and " meta- connecting" methyl on molecular packing and properties of these PIs was investigated. These data provided a useful guide to develop high performance PBIIs by incorporating N-methyl. Image 1 • Two novel diamines (m -MePABZ and p -MePABZ) were successfully synthesized. • The effect of " para -" and " meta- connecting" methyl on molecular packing and properties of these PBIIs was investigated. • m -MePABZ-PMDA film illustrated an ultra-low CTE of 2.5 ppm K-1 and an extremely high T g of 431 °C. [ABSTRACT FROM AUTHOR]

A novel highly transparent polyimide film with reduced CTE value was synthesized by introducing bulky pendent group and amide unit and the effects of designed structures on the optical transparency and dimensional stability of polyimide film were studied in detail. [Display omitted] • Several PI films were fabricated by introducing bulky pendent group and amide unit. • The effects of introduced groups on the properties of PI films were studied. • The film possesses good optical properties with λ cutoff of 384 nm and T 450 nm of 81%. • The film with designed structure displays reduced CTE value of 45 ppm/℃. Monomers of 4,4′-((4-(trifluoromethyl)phenyl)methylene)bis(2,6-dimethylaniline) (3FTMDT) and N,N'-(2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diyl)bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxamide) (TA-TFMB) were synthesized and designed to fabricate polyimide film with simultaneously designed bulky pendent group and amide unit in polymer chains and their effects on the optical transparency and dimensional stability of films were investigated in detail. The prepared polyimide (3FTMDT/TA-TFMB) film possesses highly optical transparency (λ cutoff = 384 nm, T 450 nm = 81%, Haze = 0.86) and lighter color (L *=95.09, a *=-2.14, b *=6.44) with the in-plane coefficient of linear thermal expansion of 45 ppm/oC. Meanwhile, the film presents good thermal stability and mechanical properties, with a glass transition temperature (T g) of 337 °C and 5 wt% decomposition temperature of 459 °C under N 2 , the fracture strength and tensile modulus of the film are 105 MPa and 2.2 GPa, respectively. The film also exhibits low dielectric performances with intrinsic dielectric constant of 2.29 and dielectric loss of 8 × 10-3 at 10 KHz, and which could keep stable up to 280 °C. In addition, the film shows good solubility in common solvents and is easy to be processed. The highly transparent polyimide film with reduced coefficient of linear thermal expansion is expected to be used as substrate material for flexible display or other photoelectric fields. [ABSTRACT FROM AUTHOR]

In this paper, we present a synthetic strategy for N-phenyl substituted benzimidazole-derived diamines, including 2-(4-(4-aminophenoxy) phenyl)-1-phenyl-1H-benzo[d]imidazole-5-amine (para-diamine) and 2-(3-(4-aminophenoxy) phenyl)-1-phenyl-1H-benzo[d]imidazole-5-amine (meta-diamine). Two distinct series of N-phenyl substituted poly (benzimidazole imide)s (PBIPIs) were synthesized via reaction with different aromatic dianhydrides. The simulation reveals distinct amine reaction activities of two diamine monomers. The obtained PBIPIs exhibit exceptional heat resistance attributed to N-phenyl substituted benzimidazole (BI). The temperature at which weight loss of 5 % (T 5%) is in the range of 491–595 °C under N 2 environment, while the glass transition temperature is 237–329 °C. The PBIPIs exhibit specific solubility characteristics due to the flexible ether linkage groups' non-coplanarity and bulky pendant benzene groups. The PBIPIs possess tensile strength between 108 and 142 MPa, a tensile modulus of 4.0–5.9 GPa, and an elongation at a break of 4.2–26.4 %, indicating excellent mechanical properties. Additionally, the PBIPI with controlled molecular weight generated from BPADA incorporating 2-(3-(4-aminophenoxy) phenyl)-1-phenyl-1H-benzo[d]imidazole-5-amine (B-BPADA-PA) demonstrates exceptional melt processability. B-BPADA-PA possesses remarkable melt stability since its minimum complex viscosity is only 2100 Pa⋅s at 400 °C, and its melt viscosity ratio is 1.34 at 380 °C. [Display omitted] • The N-phenyl substituted benzimidazole-derived diamines were designed by a cleverly synthetic strategy. • The PBIPIs possessed excellent thermal resistance and superior mechanical properties. • The PBIPIs exhibited good solubility characteristics and extremely low water absorption. • B-BPADA-PA exhibited good melt processability with a minimum complex viscosity of 2100 Pa⋅s at 400 °C. [ABSTRACT FROM AUTHOR]

Membranes with low dielectric constant and high moisture resistance are the key material for miniaturized and integrated communication equipment as an interlayer dielectric layer. Here, a series of cross-linked PI aerogel membranes were prepared by co-polymerization and scraping coating technology. The introduction of the fluorinated blocks and benzimidazole ring structures can consequently garner novel PI aerogel membranes with fascinating dielectric properties and outstanding moisture resistance. The dielectric constants of the sample membranes are as low as 1.33 at 1 KHz and 1.32 at 1 MHz with dielectric loss as low as 0.0079 at 1 KHz and 0.0035 at 1 MHz. The water contact angle can reach 107.35° with a surface roughness value of 30.428 nm. Moreover, the PI aerogel membranes have high specific surface area and excellent thermal and mechanical properties. The thermal conductivity as low as 35.4 mW m−1 K−1 at room temperature indicates excellent thermal insulation performance. PIAM-2 is suitable as an interlayer dielectric layer for electronic components under harsh environment. In addition, the influence of surface roughness on surface wettability was also elaborated on which can provide a feasible method for the preparation of low dielectric materials with moisture resistance. [Display omitted] • PI aerogels are prepared by co-polymerization and scraping coating technology via supercritical CO 2 drying. • The synergistic effect of diamines makes aerogels with excellent thermal and mechanical property. • Thermal conductivity as low as 35.4 mW m−1K−1 indicates aerogels have super thermal insulation performance. • PIAM-2 has excellent moisture resistance with water contact angle of 107.35° and surface roughness of 30.428 nm. • Dielectric constant of PIAM-2 reaches 1.32 with dielectric loss 0.0035 at 1 MHz suitable as interlayer dielectric layers. [ABSTRACT FROM AUTHOR]

Novel diamines containing spirobisbenzoxazole scaffold structure were successfully synthesized. These diamines were homopolymerized with commercial 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and cyclohexanedianhydride (H'PMDA) to prepare a series of benzoxazole based polyimides (PBOIs). The obtained PBOIs exhibited good organic solubility and outstanding thermal properties, including glass transition temperature (T g) of 355–400 °C and 5% thermal decomposition temperatures (T d5%) of 474–490 °C. Meanwhile, these polymer films exhibited excellent mechanical strength, such as tensile strength of 79.4–92.1 MPa and elongation at break of 19.5%∼31.2%. In addition, such PBOIs have been proved to be novel microporous polymer with pore width distribution of 5–7 Å and BET surface area of 281–378 m2/g. The permeability-selectivity relationship of H'PMDA based PBOIs was close to the 2008 Robeson upper bound for CO 2 /CH 4 and O 2 /N 2 gas pairs, showing promise in the field of gas separation. [Display omitted] • Spirobibenzoxazole scaffold based Polyimides. • Good solubility and microporosity. • The permeability-selectivity relationship of H'PMDA based polyimides for CO 2 /CH 4 and O 2 /N 2 gas pairs close to the 2008 Robeson upper bound. [ABSTRACT FROM AUTHOR]

To prepare colorless polyimides (CPIs), two novel diamines, namely 6-amino-2-(2′-methyl-4′-aminobenzene)-N-phenylbenzimidazol (5a) and 6-amino-2-(2′-trifluoromethyl-4′-aminobenzene)-N-phenylbenzimidazol (5b) were synthesized, and two series of polyimides derived from them were developed. Except for the inherent asymmetric structures, the twisted moieties had been successfully incorporated in the benzimidazole dianmines through 2′- and N-substituents. The loose chain packing and hindered charge transfer (CT) interaction caused by the askew and distorted segments provided the polyimides with excellent optical transparency (80% transmittance at 400 nm, semi-alicyclic series), while the resulting films inherited the unique superheat-resistance of poly(benzimidazole imide)s (PBIIs), e.g., high glass-transition temperatures (up to 402 °C). Such outstanding optical and thermal properties expanded their application as heat-resistant colorless materials. Furthermore, the correlation between various 2′-substituents and characters of these PBII films was systematically analyzed. These data indicated that these colorless polyimides had potential application as optical and optoelectronic materials. [Display omitted] • Two novel benzimidazole dianmines containing 2′- and N-substituents (5a and 5b) were successfully synthesized. • Polyimide films with asymmetric and twisted structures were successfully synthesized. • The semi-aromatic poly(benzimidazole imide) films achieved colorlessness (T 400 = 80–81% and T g = 394–402 °C). • The effect of various 2′-substitutions on the properties of these N-phenyl-poly(benzimidazole imide)s was investigated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel spirobisbenzoxazole-based polyimides of intrinsic microporosity were prepared. • The polyimides showed good solubility, excellent thermal and mechanical properties. • Discuss the rotation restriction and thermal annealing process on gas permeation behavior. Improving the processability and permeability of aromatic polyimides is a prerequisite for promoting the application in the field of gas separation membranes. Here, a series of novel spirobisbenzoxazole-based polyimides were synthesized. The novel spirobisbenzoxazole unit showed a larger rigid step size than the reported spirobisindane unit, which more effectively destroyed the molecular packing. As a result, the obtained aromatic polyimides showed good organic solubility and significantly improved gas permeability. Such polyimides were also considered as polymers of intrinsic microporous (PIMs) with ultra-micropore distribution of 5 ∼ 7 Å and high BET surface areas ranging from 373 to 449 m2/g. Meanwhile, the obtained polyimide membranes exhibited excellent thermal properties (T g > 400 °C) and outstanding mechanical properties (σ > 100 MPa). The effects of rotation restriction and thermal annealing process on gas permeation behavior were also studied. [ABSTRACT FROM AUTHOR]

Herein, we obtained porous hollow carboxyl-polysulfone (PH-CPSF) microspheres through non-solvent-induced phase separation (NIPS) method and simple modification, used as highly efficient adsorbents for removing cationic dyes from sewage. The resulting PH-CPSF microspheres possess a hollow core and sponge-like shell structure, with high surface area, durable chemical inertness and structural stability. The as-synthesized PH-CPSF microspheres deliver a desirable adsorption effect after deprotonation treatment, with an adsorption capacity reaching up to 154.5 mg g−1 at 25 °C (pH = 7) of methylene blue (MB). The inter-molecular interactions between MB and the surface of the PH-CPSF, including π-π interaction, hydrogen bonding, strong charge attraction and weak charge attraction endow the adsorption ability of the PH-CPSF. The pseudo-second-order kinetic model pronounces in the adsorption behavior, and the adsorption equilibrium data is fitted to the Langmuir model. Moreover, PH-CPSF microspheres can also be used as adsorption fillers for large-scale water purification, and a removal rate of 94.0% for MB can be achieved under a flow rate of 8000 L m−3 h−1. The reusability of 95.3% removal effect for PH-CPSF microspheres after 20 consecutive cycles can be attained by a simple regeneration treatment. The adsorption efficiency of the PH-CPSF microspheres was evaluated by variety of cationic and anionic dyes, with high adsorption capacity toward cationic dyes (100%) and less than 10% toward anionic dyes. These results manifest that PH-CPSF microspheres are a potential adsorbent with long-term purification capabilities, which are expected to be used in small and large-scale sewage treatment. [Display omitted] • Carboxyl polysulfone (PH-CPSF) microspheres were prepared by the non-solvent-induced phase separation and click reaction. • The as-obtained PH-CPSF possess honeycomb core-shell and porous hollow structure with abundant functional groups. • Highly selective cationic dyes remove efficiency, mechanical/chemical stability and reusability are achieved by PH-CPSF. • The functional PH-CPSF show its potential for large-scaled sewage purification. [ABSTRACT FROM AUTHOR]

[Display omitted] • Poly(benzimidazole imide) films with asymmetric and twisted structures was successfully synthesized. • These poly(benzimidazole imide)s achieved more prominent properties than traditional poly(benzimidazole imide)s. • The semi-aromatic poly(benzimidazole imide)s were expected to be expanded as heat-resistant colorless materials. • The effect of various 2′-substitutions on the properties of these poly(benzimidazole imide)s was discussed. To prepare colorless polyimide (CPI) films with high thermal properties, an effective design strategy is incorporating asymmetric and twisted structures in the polymer chain-segments. Based on this strategy, 6,4′-diamino-2′-methyl-1-methyl-2-phenylbenzimidazole (5a) and 6,4′-diamino-2′-trifluoromethyl-1-methyl-2-phenylbenzimidazole (5b) were synthesized, and two series of their polyimides (semi- and fully aromatic series) were prepared, respectively. The obtained poly(benzimidazole imide)s (PBIIs) with loosely packed but rigid backbones possessed not only high glass transition temperature (T g) but also improved optical transparency. In particular, the semi-aromatic system achieved an excellent transmittance about 80% at 400 nm and an outstanding T g exceeding 400 °C. Furthermore, the influence of various 2′-substitutions on the combination properties of these poly(benzimidazole imide)s was systematically analyzed. These data expand the poly(benzimidazole imide)s as optical materials and provide a feasible method to prepare heat-resistant colorless polymers. [ABSTRACT FROM AUTHOR]

• Relationship between secondary metabolites and morphological variations. • 40 Cultivars of tartary buckwheat seeds from different regions. • Targeted metabolomics of flavonoids and anthraquinones. • Groats and hulls of tartary buckwheat seeds were studied respectively. Polyphenols (flavonoids and anthraquinones) are one of the most important phytochemicals in Fagopyrum tataricum L. Gaertn. (tartary buckwheat). However, the relationship between the polyphenols of tartary buckwheat seeds and their morphological variations is unclear. We developed a liquid chromatography–mass spectrometry-based targeted metabolomics method to study the chemical profiles of 60 flavonoids and 11 anthraquinones in 40 seed cultivars (groats and hulls). Both flavonoids and anthraquinones were related to variations in seed color; the fold change from yellowish-brown to black seeds was 1.24–1.55 in groats and 0.26–0.76 in hulls. Only flavonoids contributed to significant differences in seed shape; the fold change from long to short seeds was 1.29–1.78 in groats and 1.39–1.44 in hulls. Some differential metabolites were identified at higher concentrations in hulls than in groats. This study provides new insights into differences in polyphenols among tartary buckwheat seeds with different color and shape. [ABSTRACT FROM AUTHOR]