The Mechanical Performance and Reaction Mechanism of Slag-Based Organic-Inorganic Composite Geopolymers.

A series of organic-inorganic composite geopolymer paste samples were prepared with slag-based geopolymer and three types of hydrophilic organic polymers, i.e., PVA, PAA, and CPAM, by ordinary molding and pressure-mixing processes. The reaction mechanism between slag-based geopolymer and organic polymers was studied by FT-IR, NMR, and SEM techniques. The experimental results showed that the slag-based geopolymer with the addition of 3% PVA presented the highest 28-day flexural strength of 19.0 MPa by means of a pressure-mixing process and drying curing conditions (80 °C, 24 h) compared with the geopolymers incorporating PAA and CPAM. A more homogeneous dispersion morphology was also observed by BSE and SEM for the 3% PVA-incorporated slag-based geopolymer. The FT-IR testing results confirmed the formation of a C-O-Si (Al) bond between PVA and the slag-based geopolymer. The deconvolution of the Q3 and Q2(1Al) species obtained by 29Si NMR testing manifested the addition of PVA and increased the length of the silicon backbone chain in the geopolymer. These findings confirmed that a composite geopolymer with high toughness can be produced based on the interpenetrating network structure formed between organic polymers and inorganic geopolymer.

DNA Assembly of Plasmonic Nanostructures Enables In Vivo SERS-Based MicroRNA Detection and Tumor Photoacoustic Imaging.

Controllable self-assembly of the DNA-linked gold nanoparticle (AuNP) architecture for in vivo biomedical applications remains a key challenge. Here, we describe the use of the programmed DNA tetrahedral structure to control the assembly of three different types of AuNPs (∼20, 10, and 5 nm) by organizing them into defined positioning and arrangement. A DNA-assembled "core-satellite" architecture is built by DNA sequencing where satellite AuNPs (10 and 5 nm) surround a central core AuNP (20 nm). The density and arrangement of the AuNP satellites around the core AuNP were controlled by tuning the size and amount of the DNA tetrahedron functionalized on the core AuNPs, resulting in strong electromagnetic field enhancement derived from hybridized plasmonic coupling effects. By conjugating with the Raman molecule, strong surface-enhanced Raman scattering photoacoustic imaging signals could be generated, which were able to image microRNA-21 and tumor tissues in vivo. These results provided an efficient strategy to build precision plasmonic superstructures in plasmonic-based bioanalysis and imaging.

RNA-Cleaving DNAzyme-Based Amplification Strategies for Biosensing and Therapy.

Since their first discovery in 1994, DNAzymes have been extensively applied in biosensing and therapy that act as recognition elements and signal generators with the outstanding properties of good stability, simple synthesis, and high sensitivity. One subset, RNA-cleaving DNAzymes, is widely employed for diverse applications, including as reporters capable of transmitting detectable signals. In this review, the recent advances of RNA-cleaving DNAzyme-based amplification strategies in scaled-up biosensing are focused, the application in diagnosis and disease treatment are also discussed. Two major types of RNA-cleaving DNAzyme-based amplification strategies are highlighted, namely direct response amplification strategies and combinational response amplification strategies. The direct response amplification strategies refer to those based on novel designed single-stranded DNAzyme, and the combinational response amplification strategies mainly include two-part assembled DNAzyme, cascade reactions, CHA/HCR/RCA, DNA walker, CRISPR-Cas12a and aptamer. Finally, the current status of DNAzymes, the challenges, and the prospects of DNAzyme-based biosensors are presented.

Effect of Organic Polymers on Mechanical Property and Toughening Mechanism of Slag Geopolymer Matrix.

In this work, two series of chemically reactive polymers, silane coupling agents (SCAs) and water-soluble polymers, were specifically designed as an additive to improve the ductility of slag geopolymer paste by vibration pressure technique. The influences of organic polymers on the fluidity, rheological behavior, mechanical property, porosity, and toughening mechanism of slag geopolymer were investigated. The polycondensation and bonding characteristics of organic-inorganic products were calculated by 1H liquid nuclear magnetic resonance (NMR) technology and Fourier transform infrared (FT-IR). The polymerization degree of composite geopolymer was evaluated by 29Si NMR and X-ray photoelectron spectroscopy (XPS). The microscopic morphology of the geopolymer matrix was analyzed using scanning electron microscopy (SEM). The results showed that the dosage of the KH570 and PAA-Na with 5 wt% behaved best in improving the flexural strength and the compressive strength of geopolymer in their corresponding organic series, respectively. The addition of polymers decreased the fluidity and the fluidity loss ratio of geopolymer slurry but reduced the harmful pores of hardened geopolymer. The organic polymers acting as bridge-fixed water molecules weakened the repulsion force, and formed a three-dimensional network through molecular interweaving in a geopolymer matrix. Methacryloxy in silane coupling agents and carboxyl group in water-soluble polymers may contribute to the improvement of hydration product structure through strong bonding with C-A-S-H. Microscopic measurements indicated that the addition of KH570 and PAA-Na in geopolymer could form 73.55% and 72.48% Si-O-Si with C-A-S-H gel, higher than the reference, and increase the polycondensation degree of C-A-S-H phase, reflected by the increased generation of Q2 and Q2(1Al) and the longer chain length, leading to a higher densified geopolymer matrix with high ductility.

Engineering Metal-Organic Framework Hybrid AIEgens with Tumor-Activated Accumulation and Emission for the Image-Guided GSH Depletion ROS Therapy.

Aggregation-induced emission (AIE)-active luminogens (AIEgens) have demonstrated exciting potential for the application in cancer phototheranostics. However, simultaneously achieving tumor-activated bright emission, enhanced reactive oxygen species (ROS) generation, high tumor accumulation, and minimized ROS depletion remains challenging. Here, a metal-organic framework (MOF) hybrid AIEgen theranostic platform is designed, termed A-NUiO@DCDA@ZIF-Cu, composed of an AIEgen-loaded hydrophobic UiO-66 (A-NUiO@DCDA) core and a Cu-doped hydrophilic ZIF-8 (ZIF-Cu) shell. The fluorescence emission and therapeutic ROS activity of AIEgens are restrained during delivery. After uptake by tumor tissues, ZIF-Cu decomposition occurs in response to an acidic tumor microenvironment (TME), and the hydrophobic A-NUiO@DCDA cores self-assemble into large particles, extremely increasing the tumor accumulation of AIEgens. This results in enhanced fluorescence imaging (FLI) and highly improved 1O2 generation ability during photodynamic therapy (PDT). Meanwhile, the released Cu2+ reacts to glutathione (GSH) to generate Cu+, which provides an extra chemodynamic therapy (CDT) function through Fenton-like reactions with overexpressed H2O2, resulting in the GSH depletion-enhanced ROS therapy. As a result of these characteristics, the MOF hybrid AIEgens can selectively kill tumors with excellent efficacy.

Static gain estimation for nonlinear dynamic systems from steady-state values hidden in historical data.

Static gains are often required for control, diagnosis and optimization of nonlinear dynamic systems. This paper proposes a new approach to estimate static gains for nonlinear dynamic systems from steady-state values hidden in historical data. First, steady-state values of system inputs and outputs are extracted by automatically finding data segments in steady-state conditions. Second, static gains of nonlinear dynamic systems in different operating conditions are estimated via linear regression from these steady-state values. The proposed approach has two practical features: (i) estimated static gains can be verified in a convincing way, because the validness of extracted steady-state values is confirmed by visualizing data segments in steady-state conditions, and the accuracy of estimated static gains is verified by comparing the extracted steady-state values and their estimates; (ii) the proposed approach is simple to understand and implement in practice, since it only involves a linear equation between steady-state values and static gains, as well as a basic technique of linear regression. Numerical simulation and industrial application demonstrate the effectiveness of the proposed approach.

[Effect of acupuncture for regulating spleen and stomach on aspirin resistance in patients with type 2 diabetes mellitus: a randomized controlled trial].

OBJECTIVE: To observe the effect of acupuncture for regulating spleen and stomach on aspirin resistance in patients with type 2 diabetes mellitus (T2DM) and explore the effect mechanism. METHODS: A total of 68 T2DM patients complicated with aspirin resistance were randomized into an observation group and a control group, 34 cases in each one. On the base of the conventional treatment for diabetes, aspirin enteric-coated tablets were prescribed for oral administration, 100 mg each time, once daily in the control group. In the observation group, on the basis of the treatment as the control group, acupuncture was used for regulating spleen and stomach at Zhongwan (CV 12), Zusanli (ST 36), Yinlingquan (SP 9), Hegu (LI 4), etc., once daily. The treatment for 1 week was as one course and 4 courses of treatment were required totally in two groups. Before and After treatment, the indexes of platelet function (platelet aggregation rate [PAG] and salicylic acid concentration), the indexes of vascular endothelial function (6-keone prostaglandin F1α[6-keto-PGF1α], thromin B2 [TXB2] and cyclooxysynthase-2 [COX-2]), blood glucose (fasting plasma glucose [FPG], 2 h plasma glucose [2h PG] and glycosylated hemoglobin [HbA1c]), insulin resistance index (HOMA-IR), blood lipid indexes (total cholesterol [TC], triacylglycerol [TG], high-density lipoprotein cholesterol [HDL-C] and low-density lipoprotein cholesterol [LDL-C]) and the total score of TCM symptoms were observed in the patients of two groups. Clinical therapeutic effect and safety was compared in the patients between the two groups after treatment and the recurrence rate of cardiocerebrovascular events was followed up 6 months after treatment. RESULTS: After treatment, PAG, salicylic acid concentration, TXB2, COX-2, FPG, 2h PG, HbA1c, HOMA-IR, LDL-C, TC, TG and the total scores of TCM symptoms were all reduced as compared with those before treatment in the two groups (P<0.01, P<0.05), and 6-keto-PGF1αand HDL-C were increased as compared with those before treatment in the two groups (P<0.01, P<0.05). In comparison with the control group, the aforementioned indexes in the observation group were all improved significantly (P<0.01). The total effective rate was 91.2% (31/34) in the observation group, higher than 70.6% (24/34) in the control group (P<0.05). In follow up visit, the recurrence rate of cardiocerebrovascular events was 14.7% (5/34) in the observation group, lower than 29.4% (10/34) in the control group (P<0.05). The therapies were safe and had no obvious adverse reactions in both two groups. CONCLUSION: Acupuncture for regulating spleen and stomach combined with aspirin enteric-coated tablets relieve insulin resistance and reduces blood glucose and lipid as well as the recurrence rate of cardiocerebrovascular events in the patients with T2DM, which is probably related to the regulation of insulin resistance and the improvement of vascular endothelial function. This combined therapy achieves the better effect on aspirin resistance as compared with simple aspirin enteric-coated tablets.