The Effect of Expanded Vermiculite on the Fire Resistance of Waterborne Acrylic Coatings.

Due to their ability to prevent or slow the spread of fires, fire-retardant coatings are utilized as the main means of fire protection for steel structures, combining easy application and high economic efficiency. This study investigates the effects of the particle size and dosage of expanded vermiculite (EV) on the fire resistance and application performance of coatings. Ammonium polyphosphate, melamine, and pentaerythritol were used as intumescent fire-retardant systems, along with waterborne hydroxyl-modified acrylic resins as the film-forming substances. The properties of fire resistance coatings were tested via scanning electron microscope (SEM), X-ray diffractometry (XRD), thermogravimetric analysis (TGA), limiting oxygen index (LOI), and cone calorimetry. The excellent fire performance of the coatings with 3 wt.% 300-mesh EV was proven, exhibiting a relative expansion of 30.43 times. Moreover, the surface structure of the charcoal layer was dense. The total smoke production (TSP) and smoke concentration (TSR) were only 0.18 m2 and 0.25 m2/m2.

Brain developmental and cortical connectivity changes in transgenic monkeys carrying the human-specific duplicated gene SRGAP2C.

Human-specific duplicated genes contributed to phenotypic innovations during the origin of our own species, such as an enlarged brain and highly developed cognitive abilities. While prior studies on transgenic mice carrying the human-specific SRGAP2C gene have shown enhanced brain connectivity, the relevance to humans remains unclear due to the significant evolutionary gap between humans and rodents. In this study, to investigate the phenotypic outcome and underlying genetic mechanism of SRGAP2C, we generated transgenic cynomolgus macaques (Macaca fascicularis) carrying the human-specific SRGAP2C gene. Longitudinal MRI imaging revealed delayed brain development with region-specific volume changes, accompanied by altered myelination levels in the temporal and occipital regions. On a cellular level, the transgenic monkeys exhibited increased deep-layer neurons during fetal neurogenesis and delayed synaptic maturation in adolescence. Moreover, transcriptome analysis detected neotenic expression in molecular pathways related to neuron ensheathment, synaptic connections, extracellular matrix and energy metabolism. Cognitively, the transgenic monkeys demonstrated improved motor planning and execution skills. Together, our findings provide new insights into the mechanisms by which the newly evolved gene shapes the unique development and circuitry of the human brain.

Chinese herbal medicine combined with cognitive-behavioural therapy for avoidant paruresis: a controlled trial.

Background: Avoidant paruresis is a common clinical condition in urology and psychosomatic medicine. However, it has limited treatment options that are safe and effective with few side effects. Aims: Our study aimed to investigate the effectiveness and safety of the Chinese herbal Yangxin Tongquan decoction combined with cognitive-behavioural therapy (CBT) for avoidant paruresis. Methods: Sixty-eight patients with avoidant paruresis were divided into a treatment group (33 patients) and a control group (35 patients). The control group was assigned 10 weeks of CBT and systematic desensitisation. In addition to CBT and systematic desensitisation, the treatment group was given the Chinese herbal Yangxin Tongquan decoction during the 10-week study. The Shy Bladder Syndrome Scale (SBS) and the Self-rating Anxiety Scale (SAS) were administered before and after treatment to measure any change. Results: The overall efficacy in the treatment group (n=30) was 80.0% vs 62.5% in the control group (n=33). Comparing pretreatment and post-treatment measures, both groups showed improvement in SBS scores and SAS scores (treatment group: t(SBS) =8.397, p(SBS) <0.001, t(SAS) =8.216, p(SAS)<0.001; control group: t(SBS) =6.802, p(SBS) <0.001, t(SAS)=5.171, p(SAS) <0.001). Moreover, both groups' SBS and SAS scores changed significantly over time (SBS scores: Ftime =118.299, p<0.001; SAS scores: Ftime =92.114, p<0.001). However, the treatment group performed better than the control group (SBS scores: Ftime*group =5.709, p=0.020; SAS scores: Ftime*group =7.235, p=0.009). Conclusions: The Chinese herbal Yangxin Tongquan decoction combined with cognitive-behavioural psychotherapy positively affects the treatment of avoidant paruresis without significant adverse effects.

Temperature Responsive Diblock Polymer Brushes as Nanoreactors for Silver Nanoparticles Catalysis.

Metal nanoparticles are widely used in catalysis. Loading metal nanoparticles into polymer brushes has aroused wide attention, but regulation of catalytic performance still needs to be improved. The novel diblock polymer brushes, polystyrene@sodium polystyrene sulfonate-b-poly (N-isopropylacrylamide) (PSV@PSS-b-PNIPA) and PSV@PNIPA-b-PSS with reversed block sequence, were prepared by surface initiated photoiniferter-mediated polymerization (SI-PIMP) and used as nanoreactors to load silver nanoparticles (AgNPs). The block sequence caused the difference of conformation and further affected the catalytic performance. PSV@PNIPA-b-PSS@Ag was found to be able to control the amount of AgNPs exposed to external reactant of 4-nitrophenol at different temperatures to achieve regulation of the reaction rate due to the hydrogen bonds and further physical crosslinking between PNIPA and PSS.

Study on the Synthesis and Properties of Waterborne Polyurea Modified by Epoxy Resin.

The most notable features of polyurea are its fast reaction, energy-saving and high efficiency. In order to meet the needs of environmental protection, waterborne polyurea (WPUA) has become a research hotspot. However, the presence of hydrophilic groups in WPUA reduces its solvent resistance, heat resistance and mechanical properties. Therefore, it is necessary and valuable to develop a high-performance WPUA. In this study, epoxy-modified waterborne polyurea (WPUAE) emulsions were prepared using epoxy resin as a modifier. Fourier transform infrared spectroscopy (FT-IR) showed that E44 was successfully introduced into the molecular chain of WPUA. The WPUAE was tested for gel fraction, adhesion, contact angle, solvent resistance, tensile properties and thermal stability. The results showed that when the E44 content was 8 wt%, the performance of WPUAE was best, the adhesion of WPUAE coating film was 1.53 MPa, the gel fraction, water contact angle, water absorption, toluene absorption, tensile strength and decomposition temperature were 96.94%, 70.3°, 16.43%, 131.04%, 9.05 MPa and 365 °C, respectively. The results showed that epoxy resin as an emulsion modifier improved the comprehensive properties of WPUA.

Comparison of lncRNA Expression in the Uterus between Periods of Embryo Implantation and Labor in Mice.

Uterine function during pregnancy is regulated mainly by progesterone (P4) and estrogen (E2). Serum P4 levels are known to fluctuate significantly over the course of pregnancy, especially during embryo implantation and labor. In this study, pregnant mice at E0.5, E4.5, E15.5, and E18.5 (n = 3/E) were used for an RNA-Seq-based analysis of mRNA and lncRNA expression. In this analysis, 1971 differentially expressed (DE) mRNAs, 493 known DE lncRNAs, and 1041 novel DE lncRNAs were found between E0.5 and E4.5 at the embryo implantation stage, while 1149 DE mRNAs, 192 known DE lncRNAs, and 218 novel DE lncRNAs were found between E15.5 and E18.5 at the labor stage. The expression level of lncRNA-MMP11 was significantly downregulated by P4 treatment on MSM cells, while lncRNA-ANKRD37 was significantly upregulated. Notably, 117 DE mRNAs, 19 known DE lncRNAs, and 31 novel DE lncRNAs were commonly expressed between the two stages, indicating that these mRNAs and lncRNAs may be directly or indirectly regulated by P4.

Boronic acid-functionalized spherical polymer brushes for efficient and selective enrichment of glycoproteins.

Glycoproteins are related to many biological activities and diseases, and thereby their efficient capture and enrichment for diagnostics and proteomics have emerged to exhibit great significance. However, the lack of materials with high binding capacity and selectivity is still a big obstacle for further application. Herein, we reported a facile and eco-friendly approach to fabricate spherical polymer brushes with multiple boronic acid groups. Specifically, the whole process can be divided into three steps, the polystyrene (PS) core was obtained by traditional emulsion polymerization, followed by immobilization of a home-made photoinitiator. Subsequently, boronic acid-functionalized polymer chains (PBA) were chemically grafted via photo-emulsion polymerization, leading to spherical polymer brushes (PS-PBA) with boronate affinity. The particle size, morphology, and composition of as-prepared spherical polymer brushes were systematically characterized. The characteristics of glycoproteins binding to the spherical polymer brushes under different conditions, including pH values and ionic strength, were also investigated. PS-PBA brushes possess fast binding speed (30 min) and high binding capacity for glycoprotein ovalbumin (OVA) (377.0 mg g-1) under physiological pH conditions at 25 °C, because the low steric hindrance of flexible polymeric PBA chains facilitates the interaction between boronic acid groups and glycoproteins. Moreover, the binding capacity of PS-PBA brushes for glycoprotein OVA was ∼6.7 times higher than that for non-glycoprotein bovine serum albumin (BSA), indicating the excellent selective adsorption. This study provided a facile and efficient approach for the fabrication of boronic acid-functionalized materials that will be useful in the enrichment and separation of glycoproteins for the diagnosis of diseases.

Conformation Variation and Tunable Protein Adsorption through Combination of Poly(acrylic acid) and Antifouling Poly(N-(2-hydroxyethyl) acrylamide) Diblock on a Particle Surface.

Adsorption and desorption of proteins on biomaterial surfaces play a critical role in numerous biomedical applications. Spherical diblock polymer brushes (polystyrene with photoiniferter (PSV) as the core) with different block sequence, poly(acrylic acid)-b-poly(N-(2-hydroxyethyl) acrylamide) (PSV@PAA-b-PHEAA) and poly(N-(2-hydroxyethyl) acrylamide)-b-poly(acrylic acid) (PSV@PHEAA-b-PAA) were prepared via surface-initiated photoiniferter-mediated polymerization (SI-PIMP) and confirmed by a series of characterizations including TEM, Fourier transform infrared (FTIR) and elemental analysis. Both diblock polymer brushes show typical pH-dependent properties measured by dynamic light scattering (DLS) and Zeta potential. It is interesting to find out that conformation of PSV@PAA-b-PHEAA uniquely change with pH values, which is due to cooperation of electrostatic repulsion and steric hindrance. High-resolution turbidimetric titration was applied to explore the behavior of bovine serum albumin (BSA) binding to diblock polymer brushes, and the protein adsorption could be tuned by the existence of PHEAA as well as apparent PAA density. These studies laid a theoretical foundation for design of diblock polymer brushes and a possible application in biomedical fields.

Hairy Fluorescent Nanospheres Based on Polyelectrolyte Brush for Highly Sensitive Determination of Cu(II).

Currently, it is an ongoing challenge to develop fluorescent nanosphere detectors that are uniform, non-toxic, stable and bearing a large number of functional groups on the surface for further applications in a variety of fields. Here, we have synthesized hairy nanospheres (HNs) with different particle sizes and a content range of carboxyl groups from 4 mmol/g to 9 mmol/g. Based on this, hairy fluorescent nanospheres (HFNs) were prepared by the traditional coupling method (TCM) or adsorption-induced coupling method (ACM). By comparison, it was found that high brightness HFNs are fabricated based on HNs with poly (acrylic acid) brushes on the surface via ACM. The fluorescence intensity of hairy fluorescent nanospheres could be controlled by tuning the content of 5-aminofluorescein (5-AF) or the carboxyl groups of HNs easily. The carboxyl content of the HFNs could be as high as 8 mmol/g for further applications. The obtained HFNs are used for the detection of heavy metal ions in environmental pollution. Among various other metal ions, the response to Cu (II) is more obvious. We demonstrated that HFNs can serve as a selective probe and for the separation and determination of Cu(II) ions with a linear range of 0-0.5 µM and a low detection limit of 64 nM.

Synthesis of poly(acrylic acid) coated magnetic nanospheres via a multiple polymerization route.

Magnetic nanospheres are versatile candidates for both fundamental and practical applications. Before they are applied in more complicated fields, their surface must be modified by several functionalities. However, the surface modification can be affected by the magnetic nanoparticles (MNP) embedded in the polymer matrix. Herein, the synthesis of poly(acrylic acid) coated magnetic nanospheres via a multiple polymerization route is described. During the synthesis process, seed emulsion polymerization was applied to redistribute the MNP in the polymer matrix, and the relationship between the structure of magnetic nanospheres and the thickness of the grafted poly(acrylic acid) layer was investigated. The development of size, morphology and magnetic properties of the nanospheres were characterized by transmission electron microscopy, dynamic light scattering, thermogravimetric analysis, X-ray diffraction and vibrating sample magnetometry. This work would pave the way to design and preparation of new structure of functional magnetic nanospheres with precise surface modification.

Stabilization of Pickering Emulsions by Hairy Nanoparticles Bearing Polyanions.

Pickering emulsions are increasingly applied in drug delivery, oil-water separation, composite materials preparation, and other fields. However, systematic studies on the stabilization of Pickering emulsions to satisfy the growing application demands in multiple fields with long-term conservation are rare. Compared to conventional solid nanoparticles, polyanion-modified hairy nanoparticles are more stable in practical environments and are investigated in this study. Poly (sodium p-styrenesulfonate) was grafted to a polystyrene (PS) core via a photoemulsion polymerization. A hairy nanoparticle bearing polyanions called poly (sodium p-styrenesulfonate) brush (PS@PSS) was synthesized. The size and uniformity of the Pickering emulsions stabilized by PS@PSS were investigated via a polarizing microscope. The stability of Pickering emulsions were optimized by adjusting critical factors like ultrasonic power and time, standing time, oil phases, salt concentration, and water:oil ratio. Results indicated that the Pickering emulsions could be stabilized by PS@PSS nanoparticles, which showed remarkable and adjustable partial wetting properties. It was found that the optimized conditions were ultrasonic power of 150 W, ultrasonic time of 3 min, salt concentration of 0.1 mM, oil phase of hexadecane, and water:oil ratio of 1:1. The formation and stability of Pickering emulsion are closely related to the hairy poly (sodium p-styrenesulfonate) brush layer on the nanoparticle surface.

Design and preparation of bi-functionalized short-chain modified zwitterionic nanoparticles.

An ideal nanomaterial for use in the bio-medical field should have a distinctive surface capable of effectively preventing nonspecific protein adsorption and identifying target bio-molecules. Recently, the short-chain zwitterion strategy has been suggested as a simple and novel approach to create outstanding anti-fouling surfaces. In this paper, the carboxyl end group of short-chain zwitterion-coated silica nanoparticles (SiO2-ZWS) was found to be difficult to functionalize via a conventional EDC/NHS strategy due to its rapid hydrolysis side-reactions. Hence, a series of bi-functionalized silica nanoparticles (SiO2-ZWS/COOH) were designed and prepared by controlling the molar ratio of 3-aminopropyltriethoxysilane (APTES) to short-chain zwitterionic organosiloxane (ZWS) in order to achieve above goal. The synthesized SiO2-ZWS/COOH had similar excellent anti-fouling properties compared with SiO2-ZWS, even in 50% fetal bovine serum characterized by DLS and turbidimetric titration. Subsequently, SiO2-ZWS/COOH5/1 was chosen as a representative and then demonstrated higher detection signal intensity and more superior signal-to-noise ratios compare with the pure SiO2-COOH when they were used as a bio-carrier for chemiluminescence enzyme immunoassay (CLEIA). These unique bi-functionalized silica nanoparticles have many potential applications in the diagnostic and therapeutic fields. STATEMENT OF SIGNIFICANCE: Reducing nonspecific protein adsorption and enhancing the immobilized efficiency of specific bio-probes are two of the most important issues for bio-carriers, particularly for a nanoparticle based bio-carrier. Herein, we designed and prepared a bi-functional nanoparticle with anti-fouling property and bio conjugation capacity for further bioassay by improving the short-chain zwitterionic modification strategy we have proposed previously. The heterogeneous surface of this nanoparticle showed effective anti-fouling properties both in model protein solutions and fetal bovine serum (FBS). The modified nanoparticles can also be successfully functionalized with a specific antibody for CLEIA assay with a prominent bio-detection performance even in 50% FBS. In this paper, we also investigated an unexpectedly fast hydrolysis behavior of NHS-activated carboxylic groups within the pure short-chain zwitterionic molecule that led to no protein binding in the short-chain zwitterion modified nanoparticle. Our findings pave a new way for the designing of high performance bio-carriers, demonstrating their strong potential as a robust platform for diagnosis and therapy.

Conformation Study of Dual Stimuli-Responsive Core-Shell Diblock Polymer Brushes.

Stimuli-responsive nanoparticles are among the most popular research topics. In this study, two types of core-shell (polystyrene with a photoiniferter (PSV) as the core and diblock as the shell) polymer brushes (PSV@PNIPA-b-PAA and PSV@PAA-b-PNIPA) were designed and prepared using surface-initiated photoiniferter-mediated polymerization (SI-PIMP). Moreover, their pH- and temperature-stimuli responses were explored by dynamic light scattering (DLS) and turbidimeter under various conditions. The results showed that the conformational change was determined on the basis of the competition among electrostatic repulsion, hydrophobic interaction, hydrogen bonding, and steric hindrance, which was also confirmed by protein adsorption experiments. These results are not only helpful for the design and synthesis of stimuli-responsive polymer brushes but also shed light on controlled protein immobilization under mild conditions.

Antifouling performance of nano-sized spherical poly(N-hydroxyethyl acrylamide) brush.

The biomedical applications of nanoparticles are still impeded by the non-specific adsorption of proteins, cells, or others biological species in vivo/in vitro. In this work, poly(N-hydroxyethyl acrylamide) was hired to modify a solid polymer core, polystyrene (PS) nanoparticles, via surface-initiated photo-emulsion polymerization to form nano-sized spherical poly(N-hydroxyethyl acrylamide) brush (PS@PHEAA). Its antifouling ability and stability were investigated by dynamic light scattering (DLS), turbidimetric titration, and isothermal titration calorimetry (ITC). The size of PS@PHEAA was constant as a function of pH, while slightly changed with ionic strength in single protein solution. ITC data confirmed that protein was slightly adsorbed on PS@PHEAA and the ionic strength influenced the adsorption. All characterizations demonstrated that PHEAA layer reduced the interaction between nanoparticles and proteins. Thus, these nanoparticles ideal candidates for future applications in the biomedical field.

Tuning of surface protein adsorption by spherical mixed charged silica brushes (MCB) with zwitterionic carboxybetaine component.

Controlled protein adsorption and release without deformation and loss of activity under mild conditions is an essential issue for biological carriers. A spherical mixed charged silica brush (MCB), which could tune protein adsorption, has been prepared by introducing zwitterionic carboxybetaine copolymer onto the surface of silica nanoparticles for the first time. The simple surface-initiated reversible addition-fragmentation chain transfer polymerization (SI-RAFT) was applied to synthesize the MCB precursor - poly(2-(dimethylamino)ethyl methacrylate) modified silica nanoparticles (SiO2@PDMAEMA). Then, the end group in PDMAEMA was quaternized with propiolactone to obtain poly(DMAEMA-co-carboxybetaine methacrylate) modified silica nanoparticles (SiO2@poly(DMAEMA-co-CBMA)), which was denoted as MCB. In comparison, fully quaternized MCB (SiO2@PCBMA) was also prepared by a one-step strategy. Physicochemical behaviours of MCB in solution were systematically studied. The zwitterionic CBMA component endows the MCB with tunable adsorption towards both acidic and basic proteins through simple adjustment of the DMAEMA to CBMA ratio under mild conditions. This study may have great potential applications in the biomedical field, including tunable drug loading and releasing, and immobilized enzymes, etc.

ß-Lactoglobulin (BLG) binding to highly charged cationic polymer-grafted magnetic nanoparticles: effect of ionic strength.

Poly(2-(methacryloyloxy)ethyltrimethyl ammonium chloride) (PMATAC) modified magnetic nanoparticles (NPs) with a high zeta potential of ca. 50mV were synthesized by atom transfer radical polymerization (ATRP). The prepared NPs consist of a magnetic core around 13nm and a PMATAC shell around 20nm attached on the surface of magnetic nanoparticles. Thermodynamic binding parameters between ß-lactoglobulin and these polycationic NPs were investigated at different ionic strengths by high-resolution turbidimetry, dynamic light scattering (DLS), and isothermal titration calorimetry (ITC). Both turbidity and ITC show that binding affinities for BLG display a non-monotonic ionic strength dependence trend and a maximum appears at ionic strength of 50mM. Such observation should arise from the coeffects of protein charge anisotropy visualized by DelPhi electrostatic modeling and the strong electrostatic repulsion among highly charged NPs at a variety of ionic strengths.

Functional short-chain zwitterion coated silica nanoparticles with antifouling property in protein solutions.

A new functional nanoparticle, consisting of a silica core onto which short-chain zwitterions are chemically connected, was successfully prepared and showed excellent antifouling performance to protein solutions. These nanoparticles (NPs) own excellent stability even in 1M NaCl solutions for at least 48 h. The interaction between these "zwitterated" NPs and proteins were investigated by dynamic light scattering (DLS), turbidimetric titration, and isothermal titration calorimetry (ITC). The results demonstrated that the zwitterated NPs had antifouling property both in single protein solutions and serum (fetal bovine serum, FBS). The zwitterated NPs also own abundant functional groups which could conjugate with biomolecules for future applications in therapeutic and diagnostic field.

Encoding through the host-guest structure: construction of multiplexed fluorescent beads.

A new encoding strategy based on the host-guest structure was developed, where encoding is achieved by combinational use of a set of guest particles with different fluorescence intensity levels at various ratios. This system was proven to be well-defined and highly controllable.

Ultrasensitive ELISA using enzyme-loaded nanospherical brushes as labels.

Improving the detection sensitivity of enzyme-linked immunosorbent assay (ELISA) is of utmost importance for meeting the demand of early disease diagnosis. Herein we report an ultrasensitive ELISA system using horseradish peroxidase (HRP)-loaded nanospherical poly(acrylic acid) brushes (SPAABs) as labels. HRP was covalently immobilized in SPAABs with high capacity and activity via an efficient "chemical conjugation after electrostatic entrapment" (CCEE) process, thus endowing SPAABs with high amplification capability as labels. The periphery of SPAAB-HRP was further utilized to bind a layer of antibody with high density for efficient capture of analytes owing to the three-dimensional architecture of SPAABs. Using human chorionic gonadotrophin (hCG) as a model analyte, the SPAAB-amplified system drastically boosted the detection limit of ELISA to 0.012 mIU mL(-1), a 267-fold improvement as compared to conventional ELISA systems.

Enhancement of enzymatic activity by magnetic spherical polyelectrolyte brushes: a potential recycling strategy for enzymes.

Interactions between amyloglucosidase and magnetic spherical polyelectrolyte brushes (MSPB) were studied by turbidimetric titration, which reveals reversible and tunable behaviors of pH-dependent enzyme-SPB binding. Quantitative thermodyanmic parameters including binding affinity and stoichiometry between enzyme and SPBs were further measured by isothermal titration calorimetry (ITC). A large amount of enzyme can be loaded in MSPB without loss of MSPB stability. We demonstrated that the enzymatic activity of amyloglucosidase bound in MSPB could be greatly enhanced (catalytic reaction rate, k(bound) = 1.36k(free)) compared to free enzyme acitivity in solution. This is tremendous improvement from other carrier systems that usually lead to a significant decrease of enzymatic activity. Both the high enzyme loading capacity and the enhancement of the catalytic activity probably arise from the Coulombic interactions between the enzyme and MSPB. These findings provide a practical strategy for enhancement of enzyme activity and enzyme recycling by MSPB.