Two new flavanones from Polytrichum commune Hedw.

Seven flavanones, including two new compounds coupled with styryl units, communins C (1) and D (2), as well as five known compounds, were isolated from Polytrichum commune Hedw. The planar structures of all compounds were determined using extensive spectroscopic analysis. The absolute configurations of two new compounds were assigned by comparing experimental ECD with calculated ECD. The cytotoxicity of all isolates against HCT-116, BGC803, MCF7 and PANC-1 cell lines was evaluated. Communin D exhibited significant cytotoxic activity on BGC803 cells with an IC50 value of 9.3 µM.

Construction of a competency framework of dental hygienists: A Delphi study.

AIM: To explore the basic and core competencies of dental hygienists, construct a systematic and scientific competency framework for dental hygienists taking into account China's national conditions and provide a theoretical basis for the future training in China and other countries that have not yet established the competencies of dental hygienists. BACKGROUND: The establishment of dental hygienists role is essential for the public to improve the dental health level. Currently, more than 50 countries around the world have established the role of dental hygienists and defined the core competencies needed by dental hygienists. However, studies on developing a standardized and unified consensus of competencies of dental hygienists are lacking in China. METHODS: Based on the literature review and theoretical research, this study explored the theoretical basis and fundamental principle of constructing the competency framework for dental hygienists. Moreover, a correspondence questionnaire on dental hygienists' competency framework was initially constructed to clarify the specific content of each competency. Finally, the Delphi method was adopted to establish the indicators of the dental hygienists' competency framework according to the principle of expert selection and inclusion criteria. RESULTS: The three rounds of Delphi consultation experts were from nursing, stomatology and management and other fields. Three rounds of Delphi results showed that the expert authority, enthusiasm and coordination coefficients were high. Thereafter, a competency framework of dental hygienists with 4 primary indicators, 15 secondary indicators and 50 tertiary indicators was constructed, which included theoretical knowledge, professional skills, professional abilities and occupational qualities. CONCLUSION: Literature and theoretical research methods along with Delphi expert consultation were used to construct the competency framework of dental hygienists based on the onion model. The competency framework of dental hygienists was scientific, reasonable and practical, which is consistent with the current health situation in China and has distinct Chinese characteristics. Some of our findings, offer ideas for other developing countries that have not yet set up the role of dental hygienists or are in an initial stage.

Study of Active Phytochemicals and Mechanisms of Cnidii Fructus in Treating Osteoporosis Based on HPLC-Q-TOF-MS/MS and Network Pharmacology.

INTRODUCTION: This study aimed to clarify the anti-osteoporosis mechanism of Cnidii Fructus (CF) via network pharmacology and experimental verification.\ Methods: HPLC fingerprints combined with HPLC-Q-TOF-MS/MS analysis confirmed common components (CCS) of CF. Then, network pharmacology was used to investigate the anti-OP mechanism of CF, including potential anti-OP phytochemicals, potential targets, and related signalling pathway. Molecular docking analysis was carried on investigating the protein-ligand interactions. Finally, in vitro experiments were performed to verify anti-OP mechanism of CF. RESULTS: In this study, 17 compounds from CF were identified by HPLC-Q-TOF-MS/MS and HPLC fingerprints and then were further screened key compounds and potential targets by PPI analysis, ingredient-target network and hub network. The key compounds were SCZ10 (Diosmin), SCZ16 (Pabulenol), SCZ6 (Osthenol), SCZ8 (Bergaptol) and SCZ4 (Xanthotoxol). The potential targets were SRC, MAPK1, PIK3CA, AKT1 and HSP90AA1. Molecular docking further analysis indicated that the five key compounds have a good binding affinity with related proteins. CCK8 assays, TRAP staining experiments, and ALP activity assays concluded that osthenol and bergaptol inhibited osteoclast formation and promoted osteoblast bone formation to improve osteoporosis. CONCLUSION: Based on network pharmacology and in vitro experiments analysis, this study revealed that CF possessed an anti-OP effect, and its potential therapeutic effect may be involved with osthenol and bergaptol from CF.

Nitrogen-Regulated Theanine and Flavonoid Biosynthesis in Tea Plant Roots: Protein-Level Regulation Revealed by Multiomics Analyses.

Theanine and flavonoids (especially proanthocyanidins) are the most important and abundant secondary metabolites synthesized in the roots of tea plants. Nitrogen promotes theanine and represses flavonoid biosynthesis in tea plant roots, but the underlying mechanism is still elusive. Here, we analyzed theanine and flavonoid metabolism in tea plant roots under nitrogen deficiency and explored the regulatory mechanism using proteome and ubiquitylome profiling together with transcriptome data. Differentially expressed proteins responsive to nitrogen deficiency were identified and found to be enriched in flavonoid, nitrogen, and amino acid metabolism pathways. The proteins responding to nitrogen deficiency at the transcriptional level, translational level, and both transcriptional and translational levels were classified. Nitrogen-deficiency-responsive and ubiquitinated proteins were further identified. Our results showed that most genes encoding enzymes in the theanine synthesis pathway, such as CsAlaDC, CsGDH, and CsGOGATs, were repressed by nitrogen deficiency at transcriptional and/or protein level(s). While a large number of enzymes in flavonoid metabolism were upregulated at the transcriptional and/or translational level(s). Importantly, the ubiquitylomic analysis identified important proteins, especially the hub enzymes in theanine and flavonoid biosynthesis, such as CsAlaDC, CsTSI, CsGS, CsPAL, and CsCHS, modified by ubiquitination. This study provided novel insights into the regulation of theanine and flavonoid biosynthesis and will contribute to future studies on the post-translational regulation of secondary metabolism in tea plants.

Author Correction: Metal-coordinated sub-10 nm membranes for water purification.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Author Correction: Metal-coordinated sub-10 nm membranes for water purification.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Metal-coordinated sub-10 nm membranes for water purification.

Ultrathin membranes with potentially high permeability are urgently demanded in water purification. However, their facile, controllable fabrication remains a grand challenge. Herein, we demonstrate a metal-coordinated approach towards defect-free and robust membranes with sub-10 nm thickness. Phytic acid, a natural strong electron donor, is assembled with metal ion-based electron acceptors to fabricate metal-organophosphate membranes (MOPMs) in aqueous solution. Metal ions with higher binding energy or ionization potential such as Fe3+ and Zr4+ can generate defect-free structure while MOPM-Fe3+ with superhydrophilicity is preferred. The membrane thickness is minimized to 8 nm by varying the ligand concentration and the pore structure of MOPM-Fe3+ is regulated by varying the Fe3+ content. The membrane with optimized MOPM-Fe3+ composition exhibits prominent water permeance (109.8 L m-2 h-1 bar-1) with dye rejections above 95% and superior stability. This strong-coordination assembly may enlighten the development of ultrathin high-performance membranes.

Graphene Oxide Membranes with Conical Nanochannels for Ultrafast Water Transport.

Membrane-based separations have been increasingly utilized to address global energy crisis and water scarcity. However, the separation efficiency often suffers from the trade-off between membrane permeability and selectivity. Although great efforts have been devoted, a membrane with both high permeability and high selectivity remains a distant prospect. Inspired by the hourglass structure and ultrafast water transport in aquaporins, we propose a novel approach to fabricating membranes with conical nanochannels to reduce the mass transfer resistance and to introduce Laplace pressure as the internal driving force, which successfully breaks the permeability/selectivity trade-off. First, sulfonated polyaniline (SPANI) nanorods were in situ-synthesized and vertically aligned on sulfonated graphene oxide (SGO) nanosheets, forming SGO-SPANI X composites. Then, the graphene oxide (GO) membranes were fabricated by assembling SGO-SPANI X composites through pressure-assisted filtration, in which the SPANI nanorods would bend and flatten on the SGO nanosheets under low shear force, forming stripe arrays on SGO nanosheets. The tilted stripe arrays between the adjacent SGO nanosheets form the conical nanochannels inside GO membranes. The conical nanochannels significantly decreased the steric hindrance and enabled the generation of Laplace pressure as the internal driving force within membranes. Consequently, the resulting membranes exhibit an ultrahigh water permeability of 1222.77 L·m-2·h-1·bar-1 and high efficiency in dye removal from water with a rejection of 90.44% and permeability of 528 L·m-2·h-1·bar-1.

Asymmetric Aerogel Membranes with Ultrafast Water Permeation for the Separation of Oil-in-Water Emulsion.

Owing to highly porous and low density attributes, aerogels have been actively utilized in catalysis and adsorption processes, but their great potential in filtration requires exploitation. In this study, an asymmetric aerogel membrane is fabricated via one-pot hydrothermal reaction-induced self-cross-linking of poly(vinyl alcohol) (PVA), which exhibits ultrafast permeation for the separation of oil-in-water emulsion. Meanwhile, carbon nanotubes are added to improve the mechanical strength of the aerogel membranes. The self-cross-linking of PVA forms the supporting layer, and the exchange of water and vapor at the interface of PVA solution and air generates the separating layer as well as abundant hydroxyl groups on the membrane surface. The density, porosity, pore size, and wettability of the aerogel membrane can be tuned by the PVA concentration. Owing to high porosity (>95%) and suitable pore size (<85 nm), the aerogel membrane exhibits high rejection (99.0%) for surfactant-stabilized oil-in-water emulsion with an ultrahigh permeation flux of 135.5 × 103 L m-2 h-1 bar-1 under gravity-driven flow, which is 2 orders of magnitude higher than commercial filtration membranes with similar rejection. Meanwhile, the aerogel membrane exhibits superhydrophilicity, superoleophobicity underwater, and excellent antifouling properties for various surfactant-stabilized oil-in-water emulsions, as indicated by the fact that the flux recovery ratio maintains more than 93% after five cycles of the filtration experiment. The findings in this study may offer a novel idea to fabricate high-throughput filtration membranes.

Synergy of the mechanical, antifouling and permeation properties of a carbon nanotube nanohybrid membrane for efficient oil/water separation.

For water treatment applications, fabricating a high permeation flux membrane with super-strong mechanical strength and excellent long-term antifouling properties remains a great challenge. In this study, robust, antifouling carbon nanotube (CNT) nanohybrid membranes have been fabricated for oil/water separation. Polyethyleneimine (PEI) with abundant amino groups and a hyperbranched structure is utilized to construct a nanocoating on a CNT surface to enhance their hydrophilicity through multiple interactions between PEI and CNTs. Secondly, the vacuum-assisted self-assembly method is utilized to fabricate free-standing membranes by filtration of CNT dispersions. Finally, trimesoyl chloride (TMC) is utilized to post-modify membranes to enhance the mechanical strength and hydrophilicity and change the surface charge through reaction between amino groups and acyl chloride groups as well as hydrolysis of acyl chloride groups into carboxyl groups. The controlled stacking of CNTs renders membranes with a hierarchical nanostructure and a high porosity, leading to high water flux. The physical and chemical crosslinking renders membranes with high mechanical strength, as measured by atomic force microscopy (AFM) and tensile strength tests. The high hydrophilicity and negatively charged surface render membranes with good antifouling properties, as evaluated by filtration experiments of various oil-in-water emulsions. This study may reveal the great prospects of CNT-based membranes with superior comprehensive properties in water treatment relevant applications.

Improving Permeation and Antifouling Performance of Polyamide Nanofiltration Membranes through the Incorporation of Arginine.

Inspired by the hydrophilicity effect of arginine (Arg) in water channel aquaporins (AQPs), Arg was incorporated into the polyamide layer during interfacial polymerization to enhance the permeation and antifouling performance of the nanofiltration (NF) membranes. Due to the presence of active amine groups, Arg became another aqueous phase monomer along with piperazine (PIP) to react with trimesoyl chloride (TMC) during interfacial polymerization, which was incorporated into the polyamide network. The resulting polyamide NF membranes were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), static water contact angle, zeta potential, and positron annihilation spectroscopy (PAS) measurement. The effects of incorporating Arg in aqueous phase on water permeability and the rejection of dyes and inorganic salts of the NF membranes were studied, respectively. Similar to its function in AQPs, Arg apparently increased the hydrophilicity and the negative charges of the membrane surface and, consequently, the permeation performance. When the addition of Arg reached 40% to PIP, the water flux was doubled and the rejection ratios of Congo red and Orange GII were still >90%. Meanwhile, the antifouling experiments verified that the modified polyamide NF membranes possessed excellent fouling-resistant performance for negatively charged foulants of BSA, emulsified oil droplet, and humic acid. The flux was decreased below 15%, and recovery even rose to 89%.

Antifouling membranes for sustainable water purification: strategies and mechanisms.

One of the greatest challenges to the sustainability of modern society is an inadequate supply of clean water. Due to its energy-saving and cost-effective features, membrane technology has become an indispensable platform technology for water purification, including seawater and brackish water desalination as well as municipal or industrial wastewater treatment. However, membrane fouling, which arises from the nonspecific interaction between membrane surface and foulants, significantly impedes the efficient application of membrane technology. Preparing antifouling membranes is a fundamental strategy to deal with pervasive fouling problems from a variety of foulants. In recent years, major advancements have been made in membrane preparation techniques and in elucidating the antifouling mechanisms of membrane processes, including ultrafiltration, nanofiltration, reverse osmosis and forward osmosis. This review will first introduce the major foulants and the principal mechanisms of membrane fouling, and then highlight the development, current status and future prospects of antifouling membranes, including antifouling strategies, preparation techniques and practical applications. In particular, the strategies and mechanisms for antifouling membranes, including passive fouling resistance and fouling release, active off-surface and on-surface strategies, will be proposed and discussed extensively.

Zwitterionic materials for antifouling membrane surface construction.

UNLABELLED: Membrane separation processes are often perplexed by severe and ubiquitous membrane fouling. Zwitterionic materials, keeping electric neutrality with equivalent positive and negative charged groups, are well known for their superior antifouling properties and have been broadly utilized to construct antifouling surfaces for medical devices, biosensors and marine coatings applications. In recent years, zwitterionic materials have been more and more frequently utilized for constructing antifouling membrane surfaces. In this review, the antifouling mechanisms of zwitterionic materials as well as their biomimetic prototypes in cell membranes will be discussed, followed by the survey of common approaches to incorporate zwitterionic materials onto membrane surfaces including surface grafting, surface segregation, biomimetic adhesion, surface coating and so on. The potential applications of these antifouling membranes are also embedded. Finally, we will present a brief perspective on the future development of zwitterionic materials modified antifouling membranes. STATEMENT OF SIGNIFICANCE: Membrane fouling is a severe problem hampering the application of membrane separation technology. The properties of membrane surfaces play a critical role in membrane fouling and antifouling behavior/performance. Antifouling membrane surface construction has evolved as a hot research issue for the development of membrane processes. Zwitterionic modification of membrane surfaces has been recognized as an effective strategy to resist membrane fouling. This review summarizes the antifouling mechanisms of zwitterionic materials inspired by cell membranes as well as the popular approaches to incorporate them onto membrane surfaces. It can help form a comprehensive knowledge about the principles and methods of modifying membrane surfaces with zwitterionic materials. Finally, we propose the possible future research directions of zwitterionic materials modified antifouling membranes.

Free-Standing Graphene Oxide-Palygorskite Nanohybrid Membrane for Oil/Water Separation.

Graphene oxide (GO) is an emerging kind of building block for advanced membranes with tunable passageway for water molecules. To synergistically manipulate the channel and surface structures/properties of GO-based membranes, the different building blocks are combined and the specific interfacial interactions are designed in this study. With vacuum-assisted filtration self-assembly, palygorskite nanorods are intercalated into adjacent GO nanosheets, and GO nanosheets are assembled into laminate structures through π-π stacking and cation cross-linking. The palygorskite nanorods in the free-standing GOP nanohybrid membranes take a 3-fold role, rendering enlarged mass transfer channels, elevating hydration capacity, and creating hierarchical nanostructures of membrane surfaces. Accordingly, the permeate fluxes from 267 L/(m(2) h) for GO membrane to 1867 L/(m(2) h) for GOP membrane. The hydration capacity and hierarchical nanostructures synergistically endow GOP membranes with underwater superoleophobic and low oil-adhesive water/membrane interfaces. Moreover, by rationally imparting chemical and physical joint defense mechanisms, the GOP membranes exhibit outstanding separation performance and antifouling properties for various oil-in-water emulsion systems (with different concentration, pH, or oil species). The high water permeability, high separation efficiency, as well as superior anti-oil-fouling properties of GOP membranes enlighten the great prospects of graphene-based nanostructured materials in water purification and wastewater treatment.

Design and synthesis of organic-inorganic hybrid capsules for biotechnological applications.

Organic-inorganic hybrid capsules, which typically possess a hollow lumen and a hybrid wall, have emerged as a novel and promising class of hybrid materials and have attracted enormous attention. In comparison to polymeric capsules or inorganic capsules, the hybrid capsules combine the intrinsic physical/chemical properties of the organic and inorganic moieties, acquire more degrees of freedom to manipulate multiple interactions, create hierarchical structures and integrate multiple functionalities. Thus, the hybrid capsules exhibit superior mechanical strength (vs. polymeric capsules) and diverse functionalities (vs. inorganic capsules), which may give new opportunities to produce high-performance materials. Much effort has been devoted to exploring innovative and effective methods for the synthesis of hybrid capsules that exhibit desirable performance in target applications. This tutorial review firstly presents a brief description of the capsular structure and hybrid materials in nature, then classifies the hybrid capsules into molecule-hybrid capsules and nano-hybrid capsules based upon the size of the organic and inorganic moieties in the capsule wall, followed by a detailed discussion of the design and synthesis of the hybrid capsules. For each kind of hybrid capsule, the state-of-the-art synthesis methods are described in detail and a critical comment is embedded. The applications of these hybrid capsules in biotechnological areas (biocatalysis, drug delivery, etc.) have also been summarized. Hopefully, this review will offer a perspective and guidelines for the future research and development of hybrid capsules.

Antifouling, high-flux nanofiltration membranes enabled by dual functional polydopamine.

A facile method for fabricating antifouling and high-flux nanofiltration (NF) membranes was developed based on bioinspired polydopamine (PDA). Polyethersulfone (PES) ultrafiltration membrane as the support was first deposited a thin PDA layer and then chemically modified by a new kind of fluorinated polyamine via Michael addition reaction between fluorinated polyamine and quinone groups of PDA. PDA coating significantly reduced the pore sizes of the PES support membrane and endowed the NF membrane with high separation performance (flux about 46.1 L/(m(2) h) under 0.1 MPa, molecular weight cutoff of about 780 Da). The grafted fluorinated polyamine on the PDA layer could form low free energy microdomains to impede the accumulation/coalescence of foulants and lower the adhesion force between foulants and the membrane, rendering the membrane surface with prominent fouling-release property. When foulant solutions (including bovine serum albumin, oil and humic acid) were filtered, the resultant NF membrane exhibited excellent antifouling properties (the minimal value of total flux decline ratio was ∼8.9%, and the flux recovery ratio reached 98.6%). It is also found that the structural stability of the NF membrane could be significantly enhanced due to the covalent bond and other intermolecular interactions between the PDA layer and the PES support.

Composite polyelectrolyte multilayer membranes for oligosaccharides nanofiltration separation.

In the present work, composite polyelectrolyte multilayer (C-PEM) membranes were fabricated by using layer-by-layer (LbL) assembly technique for oligosaccharides nanofiltration (NF) separation. Specifically, the (chitosan/poly(styrene sulfonate) (PSS))3 multilayers designated as the middle layer (ML) were first deposited on the hydrolyzed polyacrylonitrile (PAN) ultrafiltration membranes, which were designated as the support layer. Then, the (poly(allylamine hydrochloride) (PAH)/PSS)2 multilayers designated as the top layer (TL) were deposited on the ML to form C-PEM membranes. When utilized for oligosaccharides NF separation, C-PEM membranes exhibited desirable performance compared to single-paired PEM membranes such as (PAH/PSS)5 and (chitosan/PSS)5 membranes owing to the collaboration of the TL and ML. In detail, C-PEM membranes acquired a permeation flux of 3.7±0.3 L m(-2) h(-1), 100% rejection of oligosaccharides and 63.0±0.5% rejection of glucose along with a high maltose/glucose selectivity of 46, demonstrating the promising potential for one-step membrane separation of oligosaccharides mixture.

Propylbenzmethylation at Val-1(α) markedly increases the tetramer stability of the PEGylated hemoglobin: a comparison with propylation at Val-1(α).

BACKGROUND: Hemoglobin (Hb)-based oxygen carriers (HBOCs) are potential pharmaceutical agents that can be used in surgery or emergency medicine. PEGylation can modulate the vasoactivity of Hb and is a widely used approach to develop HBOCs. However, PEGylation can significantly enhance the tetramer-dimer dissociation of Hb, which may perturb the structure of Hb and increase its observed adverse effect. Thus, it is necessary to increase the tetramer stability of the PEGylated Hb. METHODS: Propylbenzmethylation at Val-1(α) of HbA was carried out to stabilize the Hb tetramer. The propylbenzmethylated Hb at Val-1(α) (PrB-Hb) was used as the starting material for site-specific PEGylation at Cys-93(ß) of Hb using maleimide PEG. Structural and functional properties, autoxidation rate and thermal stability of the resultant product (PEG-PrB-Hb) were measured. RESULTS: Propylbenzmethylation at Val-1(α) led to 25-fold and 24-fold decreases in the tetramer-dimer dissociation constant of HbA and PEG-Hb, respectively. The increased tetramer stability is due to the enhanced hydrophobicity of the area around Val-1(α) and the increased polar interaction of Hb upon propylbenzmethylation. Thus, the structural and functional properties of PEG-Hb were improved, and its autoxidation rate and thermal denaturation were decreased. CONCLUSION: Propylbenzmethylation at Val-1(α) showed higher ability than propylation at Val-1(α) to improve the structural and functional properties and decrease the side effect of PEG-Hb. GENERAL SIGNIFICANCE: Our study can facilitate the biotechnological development of stable PEGylated Hb as more advanced HBOC. Our study is also expected to improve the stability of the tetrameric or dimeric proteins (e.g., uric oxidase) by propylbenzmethylation at their N-terminus.

Efficient wastewater treatment by membranes through constructing tunable antifouling membrane surfaces.

In the present study, a facile in situ approach for constructing tunable amphiphilic or hydrophilic antifouling membrane surfaces was demonstrated by exquisitely manipulating the microphase separation and surface segregation behavior of the tailor-made ternary amphiphilic block copolymers during the commonly utilized wet phase inversion membrane-formation process. Under dead-end filtration for oily wastewater treatment, the membrane with amphiphilic surface exhibited over 99.5% retention ratio of chemical oxygen demand (COD) without appreciable membrane fouling: the water permeation flux was slightly decreased during operation (total flux decline was 6.8%) and almost completely recovered to the initial value (flux recovery ratio was more than 99.0%) after simple hydraulic washing. While for the proteins-containing wastewater treatment, the membrane with hydrophilic surface exhibited about 52.6% COD retention ratio and superior antifouling performance: only 17.0% total flux decline and also more than 99.0% flux recovery ratio. Hopefully, the present approach can be developed as a competitive platform technology for the preparation of robust and versatile antifouling membrane, leading to the high process efficiency of wastewater treatments.

Trypsin-enabled construction of anti-fouling and self-cleaning polyethersulfone membrane.

Constructing anti-fouling and self-cleaning membrane surfaces based on covalent attachment of trypsin on poly(methacrylic acid)-graft-polyethersulfone (PMAA-g-PES) membrane was reported. The carboxylic acid groups enriched on asymmetric PMAA-g-PES membrane surface were activated with 1-ethyl-(3-3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) and employed as chemical anchors for the conjugation with amino groups of trypsin. Activity assays showed that such chemically immobilized trypsin was much more active and stable than that of the physically adsorbed counterpart. Trypsin covalently attached on membrane surface could substantially resist protein fouling in dynamic flow process. The considerable enhancement of protein solution permeation flux was observed as a consequence of rapid enzymatic degradation of protein deposited onto membrane surface. The permeation flux of the membrane could be recovered upon simple hydraulic flush after protein filtration, suggesting superior self-cleaning property. After multi-cycle BSA filtration over 15-day period, the active self-cleaning membrane maintained more than 95.0% of its initial flux.