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Growing data have indicated that the miR-17-92 cluster is implicated in inflammatory response and rheumatoid arthritis (RA). This study was aimed to investigate the effects of miR-92a on the proliferation and migration of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs). Our results showed that miR-92a was significantly down-regulated in RA synovial tissue and RA-FLSs, whereas the protein level of AKT2 is increased. Restoration of miR-92a suppressed the proliferation and migration of RA-FLSs. Down-regulation of miR-92a promotes proliferation and migration of normal human FLSs. Dual luciferase reporter gene assay showed that miR-92a could specifically bind with the 3′UTR of AKT2 and significantly repressed the luciferase activity. Down-regulation or up-regulation of miR-92a significantly increased or decreased the protein and phosphorylation levels of AKT2. siRNA-mediated down-regulation of AKT2 significantly prevented cell proliferation and migration of RA-FLSs, which were similar to the effects induced by overexpression of miR-92a. Moreover, AKT2 overexpression rescued miR-92a-mediated suppressive effect on proliferation and migration of RA-FLS. Thus, miR-92a could inhibit the proliferation and migration of RA-FLSs through regulation of AKT2 expression. [ABSTRACT FROM AUTHOR]

Background MicroRNAs (miRs) play an important role in osteoclastogenesis. However, no study has investigated the underlying molecular mechanisms of miR-145 in this process. The purpose of the present study was to investigate the role of miR-145 and its post-transcriptional mechanism in the progression of osteoclast differentiation. Methods Macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear factor-kB ligand (RANKL) were used to induce osteoclastogenesis originated from bone marrow-derived macrophages (BMMs). Female C57BL/6J mice were divided into sham, OVX, OVX + NC-agomir and OVX + miR-145-agomir groups. Tartrate-resistant acid phosphatase (TRAP) staining was performed to identify osteoclasts in-vitro and in-vivo . The mRNA and protein levels in osteoclast and tibia were assayed by qRT-PCR and western blotting, respectively. Results miR-145 expression was inhibited in RANKL-induced osteoclastogenesis, whereas overexpression of miR-145 attenuated it. We further found that Smad3 is a direct target gene of miR-145 by binding with its 3′-UTR. Overexpression of miR-145 significantly suppressed Smad3 mRNA and protein expression. In-vivo , miR-145 agomir treatment inhibited osteoclast activity in OVX mice by inhibiting Smad3 expression. Conclusion We provide the evidence that over-expression of miR-145 could inhibit osteoclast differentiation, at least partially, by decreasing Smad3 expression. [ABSTRACT FROM AUTHOR]

Osteoarthritis is a type of joint disease that may lead to other joint diseases. Previous research has demonstrated that tumor necrosis factor (TNF)‑α is associated with osteoarthritis activity and pathology. The possible mechanisms of the TNF‑α‑mediated signaling pathway have not been clearly elaborated in synovial fibroblasts. The present study aimed to investigate the potential mechanisms of TNF‑α in a mouse model of iodoacetate‑induced osteoarthritis. Reverse transcription‑quantitative polymerase chain reaction, ELISA, western blotting and immunohistochemistry were performed to evaluate the role of TNF‑α in the progression of osteoarthritis. The results revealed that the serum levels of TNF‑α, interleukin (IL)‑1β, IL‑4 and IL‑6 were significantly upregulated in a mouse model of iodoacetate‑induced osteoarthritis compared with healthy mice (P<0.01). TNF‑α, IL‑1β, IL‑4 and IL‑6 mRNA and protein levels were also significantly upregulated in synovial fibroblasts in the experimental mice (P<0.01). It was demonstrated that TNF‑α increased pro‑inflammation factors matrix metalloproteinase (MMP)‑3, MMP‑9, nuclear factor (NF)‑κB and receptor activator of NF‑κB ligand (RANKL) in synovial fibroblasts. It was also observed that the toll‑like receptor (TLR)‑3 was significantly upregulated and extracellular signal‑regulated kinase (ERK) and protein kinase B (AKT) were significantly downregulated in synovial fibroblasts in osteoarthritis mice (P<0.01). An in vitro assay demonstrated that TNF‑α inhibitor decreased mRNA and protein levels of IL‑1β, IL‑4 and IL‑6 in synovial fibroblasts. The knockdown of TLR‑3 abolished the TNF‑α upregulated mRNA and protein levels of IL‑1β, IL‑4 and IL‑6 in synovial fibroblasts. In addition, the knockdown of TLR‑3 also reversed TNF‑α‑upregulated ERK and AKT expression in synovial fibroblasts. In vivo assays demonstrated that TNF‑α inhibitor significantly decreased the deposition of IL‑1β, IL‑4 and IL‑6 as well as bone destruction and significantly increased the body weight and osteoarthritis score for osteoarthritic mice (P<0.01). TNF‑α inhibitor decreased TLR‑3 and significantly increased the expression and phosphorylation of ERK and AKT in articular cartilage (P<0.01). In conclusion the results of the present study indicate that TNF‑α serves an essential role in synovial fibroblasts in osteoarthritis, suggesting that inhibition of TNF‑α may decrease inflammation via the TLR‑3‑mediated ERK/AKT signaling pathway in a mouse model of monosodium iodoacetate‑induced osteoarthritis. [ABSTRACT FROM AUTHOR]

Herein, 2-vinylpyridines as a new type of electron-poor system for the asymmetric cross Rauhut-Currier reaction are reported. 2-Vinylpyridines are chemo- and enantioselectively activated by a newly designed chiral phosphine catalyst. The new reaction provides a powerful synthetic tool for accessing structurally diverse, highly valued chiral pyridine building blocks in good yields and with high enantioselectivities. Preliminary mechanistic studies reveal that two NH protons in the catalyst are critical for the synergistic activation of the substrates and governing the stereoselectivity of this reaction. [ABSTRACT FROM AUTHOR]

SnO2/graphitic carbon nitride (g-C3N4) composites were synthesized via a facile solid-state method by using SnCl4·5H2O and urea as the precursor. The structure and morphology of the as-synthesized composites were characterized by the techniques of X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), thermogravimetry-differential thermal analysis (TG-DTA), X-ray photoelectron spectroscopy (XPS), and N2 sorption. The results indicated that the composites possessed a two-dimensional (2-D) structure, and the SnO2 nanoparticles were highly dispersed on the surface of the g-C3N4 nanosheets. The gas-sensing performance of the samples to ethanol was tested, and the SnO2/g-C3N4 nanocomposite-based sensor exhibited admirable properties. The response value (Ra/Rg) of the SnO2/g-C3N4 nanocomposite with 10 wt % 2-D g-C3N4 content-based sensor to 500 ppm of ethanol was 550 at 300 °C. However, the response value of pure SnO2 was only 320. The high surface area of SnO2/g-C3N4-10 (140 m2·g−1) and the interaction between 2-D g-C3N4 and SnO2 could strongly affect the gas-sensing property. [ABSTRACT FROM AUTHOR]

The SnO2/g-C3N4 composites were synthesized via a facile calcination method by using SnCl4·and5H2O and urea as the precursor. The structure and morphology of the as-synthesized composites were characterized by the techniques of X-ray diffraction (XRD), the field-emission scanning electron microscopy and transmission electron microscopy (SEM and TEM), energy dispersive spectrometry (EDS), thermal gravity and differential thermal analysis (TG-DTA), and N2-sorption. The analysis results indicated that the as-synthesized samples possess the two dimensional structure. Additionally, the SnO2 nanoparticles were highly dispersed on the surface of the g-C3N4nanosheets. The gas-sensing performance of the as-synthesized composites for different gases was tested. Moreover, the composite with 7 wt % g-C3N4 content (SnO2/g-C3N4-7) SnO2/g-C3N4-7 exhibits an admirable gas-sensing property to ethanol, which possesses a higher response and better selectivity than that of the pure SnO2-based sensor. The high surface area of the SnO2/g-C3N4 composite and the good electronic characteristics of the two dimensional graphitic carbon nitride are in favor of the elevated gas-sensing property. [ABSTRACT FROM AUTHOR]

A large external energy input prevents wastewater treatment from being environmentally sustainable. A net-zero-energy (NZE) wastewater treatment concept based on biomass energy recycling was proposed to avoid wasting resources and to promote energy recycling in wastewater treatment plants (WWTPs). Simultaneously, a theoretical model and boundary condition based on energy balance were established to evaluate the feasibility of achieving NZE in WWTPs; the model and condition were employed to analyze data from 20 conventional WWTPs in China. A total of six WWTPs can currently export excess energy, eight WWTPs can achieve 100% energy self-sufficiency by adjusting the metabolic material allocation, and six municipal WWTPs cannot achieve net-zero energy consumption based on the evaluation of the theoretical model. The NZE model offset 79.5% of the electricity and sludge disposal cost compared with conventional wastewater treatment. The NZE model provides a theoretical basis for the optimization of material regulation for the effective utilization of organic energy from wastewater and promotes engineering applications of the NZE concept in WWTPs. [ABSTRACT FROM AUTHOR]

Flower-like SnO2/g-C3N4 nanocomposites were synthesized via a facile hydrothermal method by using SnCl4·5H2O and urea as the precursor. The structure and morphology of the as-synthesized samples were characterized by using the X-ray powder diffraction (XRD), electron microscopy (FESEM and TEM), and Fourier transform infrared spectrometer (FT-IR) techniques. SnO2 displays the unique 3D flower-like microstructure assembled with many uniform nanorods with the lengths and diameters of about 400-600 nm and 50-100 nm, respectively. For the SnO2/g-C3N4 composites, SnO2 flower-like nanorods were coupled by a lamellar structure 2D g-C3N4. Gas sensing performance test results indicated that the response of the sensor based on 7 wt. % 2D g-C3N4-decorated SnO2 composite to 500 ppm ethanol vapor was 150 at 340 °C, which was 3.5 times higher than that of the pure flower-like SnO2 nanorods-based sensor. The gas sensing mechanism of the g-C3N4nanosheets-decorated SnO2 flower-like nanorods was discussed in relation to the heterojunction structure between g-C3N4 and SnO2. [ABSTRACT FROM AUTHOR]

The present study aimed to screen potential genes associated with metastatic prostate cancer (PCa), in order to improve the understanding of the mechanisms underlying PCa metastasis. The GSE3325 microarray dataset, which was downloaded from the Gene Expression Omnibus database, consists of seven clinically localized PCa samples, six hormone-refractory metastatic PCa samples and six benign prostate tissue samples. The Linear Models for Microarray Data package was used to identify differentially-expressed genes (DEGs) and a hierarchical cluster analysis for DEGs was performed with the pheatmap package. Furthermore, potential functions for the DEGs were predicted by a functional enrichment analysis. Subsequently, microRNAs (miRNAs) potentially involved in the regulation of PCa metastasis were identified by WebGestalt software, and the miRNA-DEG regulatory network was visualized using Cytoscape. In addition, a pathway enrichment analysis for DEGs in the regulatory network was performed. A total of 306 and 2,073 genes were differentially expressed in the clinically localized PCa and the metastatic PCa groups, respectively, as compared with the benign prostate group, of which 174 were differentially expressed in both groups. A number of the DEGs, including CAMK2D and SH3BP4, were significantly enriched in the cell cycle, and others, such as MAF, were associated with the regulation of cell proliferation. Furthermore, some DEGs (CAMK2D and PCDH17) were observed to be regulated by miR-30, whereas others (ADCY2, MAF, SH3BP4 and PCDH17) were modulated by miR-182. Additionally, ADCY2 and CAMK2D were distinctly enriched in the calcium signaling pathway. The present study identified novel DEGs, including ADCY2, CAMK2D, MAF, SH3BP4 and PCDH17, that may be involved in the metastasis of PCa. [ABSTRACT FROM AUTHOR]

To extend the visible light response of ZnO, ZnO/CuO heterostructured nanocomposite was synthesized by a hydrothermal approach. At the same time, chitosan (Ch) is considered as a very promising natural polymer. It holds not only abundant resource and low cost, but also has excellent adsorption properties to a broad range of organic pollutants and some heavy metal ions. To improve the adsorption properties of ZnO/CuO nanocomposite, ZnO/CuO/chitosan organic-inorganic composites were prepared with precipitation method. The as-prepared nanocomposites were characterized by TEM (Transmission electron microscopy), SAED pattern (Selected Area Electron Diffraction), SEM (scanning electron microscopy), UV–Vis (Ultraviolet–visible spectroscopy), PL (Photoluminescence), XRD (X-ray diffraction), TGA (Thermo Gravimetric Analyzer), Fourier transform infrared spectroscopy spectra (FTIR) et al. To examine the surface and interface properties of nanocomposites, chemical prototype sensor arrays were constructed based on ZnO, ZnO/CuO, ZnO/Cu 2 O, ZnO/CuO/chitosan, ZnO/Cu 2 O/chitosan nanocomposites and QCM (quartz crystal microbalance) arrays devices. The adsorption response behaviors of the sensor arrays to some typical volatile compounds were examined under similar conditions. The results indicated that with comparison to ZnO nanostructure, the ZnO/CuO nanocomposite exhibited enhanced adsorption properties to some typical volatile compounds greatly, and the adsorption properties of ZnO/CuO/chitosan are much better than that of ZnO/CuO nanocomposite. The adsorption of ZnO/CuO system is super to that of ZnO/Cu 2 O. Therefore, ZnO/CuO/chitosan nanocomposite not only showed broadening visible light response, but also possessed of excellent adsorption properties, and has good potential applications in photocatalysts, chemical sensors, biosensors, self-cleaning coating fields et al. [ABSTRACT FROM AUTHOR]

Ethnopharmacological relevance Fructus Alpiniae oxyphyllae ( A. oxyphylla ) is a traditional herb which is widely used in East Asian for the treatment of dyspepsia, diarrhea, abdominal pain, poor memory, inflammatory conditions and cancer. Materials and methods The cytotoxic activities of ethanol extract (EE) and five extract layers including petroleum ether (PE), dichloromethane (DCLM), acetoacetate (EtOAc), n -Butanol (n-Bu) and water fractions (WF) of A. oxyphylla were tested on HepG2, SW480, MCF-7, K562 and HUVEC cell lines using MTT assay and LDH release assay. The component analysis was performed on HPLC with gradient elution. Hoechst 33342 staining, DCFH-DA fluorescence microscopy, flow cytometry analysis, western blot and migration assays were carried out to determine the anti-cancer mechanisms of PE. Results MTT analysis showed that EE, PE and DCLM could inhibit cell proliferation on HepG2, SW480, MCF-7, K562 and HUVEC cell lines, especially PE fraction. HPLC analysis pointed out five main components which may contribute to the anti-proliferative activity of PE. Further study showed that PE increased LDH release, induced apoptosis, disrupted mitochondrial membrane potential and elevated intracellular reactive oxygen species (ROS) in HepG2 cells, whereas the antioxidant N-acetyl-l-cysteine (NAC) prevented PE-induced ROS generation. The results of western blot revealed that PE induced apoptosis in HepG2 cells by enhancing Bax/Bcl-2 ratio, increasing cytochrome c in cytosol and activating caspase-3/9. Meanwhile, high levels of ROS could induce DNA damage-mediated protein expression, AKT, ERK inactivation and SAPKs activation. Furthermore, PE conspicuously blocked the migration of HUVEC cells. Conclusion The present results demonstrated that PE induced apoptosis in HepG2 cells may be via a ROS-mediated signaling pathway. [ABSTRACT FROM AUTHOR]

Abstract: Mesoporous carbonated hydroxyapatite microspheres (MCHMs) have been converted from calcium carbonate microspheres (CCMs) by hydrothermal method. After soaking the CCMs in disodium hydrogen phosphate solutions, carbonated hydroxyapatite nanoparticles are formed via a dissolution–precipitation reaction. X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) reveal that the as-obtained samples are calcium deficient hydroxyapatite with B-type CO3 2− substitution. The transmission electron microscopy (TEM) indicates that the MCHMs are composed of many nanoparticles within the whole microspheres. These nanoparticles aggregate to form mesopores with a pore size of 4.5–14.0nm among them. The formation mechanism of MHAMs has been discussed. [Copyright &y& Elsevier]

Abstract: Carbonated hydroxyapatite/carbon nanotube composite coatings (MHCs) with mesoporous structures were fabricated by electrophoretic deposition of nacre powders and carbon nanotubes on Ti6Al4V substrates followed by treatment with a phosphate buffer solution (PBS) by microwave irradiation method. The carbon nanotubes are dispersed uniformly on the whole MHCs. The conversion mechanism of the crack-free nacre/carbonate nanotube composite coatings (NCCs) to MHCs is a dissolution-precipitation reaction. After soaking in PBS, calcium ions are released from the nacre powders and react with phosphate ions to form carbonated hydroxyapatite nanoparticles. These nanoparticles aggregate to form mesopores with the pore sizes of ~3.9nm among them. Simulated body fluid (SBF) immersion tests reveal that MHCs have a good in vitro bioactivity. [Copyright &y& Elsevier]

Objectives: Colorectal cancer is one of the most common malignancies both in men and women. Owing to metastasis and resistance, the prognosis of colorectal cancer-CRC patients remains extremely poor with chemotherapy. A disintegrin and metalloproteinase 17 (ADAM17) induces the activation of Notch pathway and contributes to the chemoresistance. This study aimed to discover a novel ADAM17 inhibitor and investigate the chemosensitization effect. Materials and methods: Pharmacophore model, western blot and enzymatic assay were used to discover ZLDI-8. Cell proliferation was determined by MTT and colony formation assay. Cell migratory and invasive ability were determined by wound healing scratch and transwell assay. Immunofluorescence images and western blot analysed the expression of Notch or epithelial-mesenchymal transition (EMT) pathway markers. Xenografts were employed to evaluate the chemosensitization effect of ZLDI-8 in vivo. Results: We found that ZLDI-8 cell-specifically inhibited the proliferation of CRC, and this effect was due to abrogation of ADAM17 and Notch pathway. Meanwhile, we reported for the first time that ZLDI-8 synergistically improved the anti-tumour and anti-metastasis activity of 5-fluorouracil or irinotecan by reversing Notch and EMT pathways. Interestingly, in vivo studies further demonstrated that ZLDI-8 promoted the anti-tumour effect of 5-fluorouracil through Notch and EMT reversal. Conclusions: A novel ADAM17 inhibitor ZLDI-8 may be a potential chemosensitizer which sensitized CRC cells to 5-fluorouracil or irinotecan by reversing Notch and EMT pathways. [ABSTRACT FROM AUTHOR]

A strategy for the facile construction of the chiral quinolinylmethanolic structure, a core featured in cinchona alkaloids, is reported. A new reactivity is harnessed by TfOH-promoted chemoselective activation of α-C-H over O-H bond in quinolinylmethanols. The new reactivity is successfully engineered with an iminium catalysis in a synergistic manner to create a powerful conjugate addition-cyclization cascade process for synthesis of chiral quinoline derived γ-butyrolactones in good yields and with good to excellent enantioselectivities. The method enables the first total synthesis of natural product broussonetine in three steps. [ABSTRACT FROM AUTHOR]

A Co(OAc)2-catalyzed trifluoromethylation and subsequent C(3)-selective arylation of 2-(propargylamino)pyridines has been developed. A new 6-endo-dig cyclization involving an unprecedented C(3) selective arylation of the pyridines instead of a commonly observed 5-exo-dig cyclization with "N" is realized. Moreover, the study presents the first case of the installation of a trifluoromethyl group into electron-deficient azaarenes. The process delivers an efficient cascade approach to new trifluoromethylated 1,8-naphthyridine structures with a broad substrate scope. [ABSTRACT FROM AUTHOR]

Megakaryocytes (MKs) are one of the few cell types that become polyploid; however, the mechanisms by which these cells are designated to become polyploid are not fully understood. In this investigation, we successfully established two relatively synchronous polyploid cell models by inducing Dami and CMK cells with SP600125. We found that SP600125 induced the polyploidization of Dami and CMK cells, concomitant with the phosphorylation of ribosomal protein S6 kinase 1 (S6K1) at Thr421/Ser424 and dephosphorylation at Thr389. The polyploidization was partially blocked by H-89, a cAMP-dependent protein kinase (PKA) inhibitor, through direct binding to S6K1, leading to dephosphorylation at Thr421/Ser424 and phosphorylation at Thr389, independent of PKA. Overexpression of a rapamycin-resistant mutant of S6K1 further enhanced the inhibitory effect of LY294002 on the SP600125-induced polyploidization of Dami and CMK cells. SP600125 also induced the polyploidization of Meg-01 cells, which are derived from a patient with chronic myelogenous leukemia, without causing a significant change in S6K1 phosphorylation. Additionally, SP600125 induced the polyploidization of HEL cells, which are derived from a patient with erythroleukemia, and phosphorylation at Thr389 of S6K1 was detected. However, the polyploidization of both Meg-01 cells and HEL cells as a result of SP600125 treatment was lower than that of SP600125-induced Dami and CMK cells, and it was not blocked by H-89 despite the increased phosphorylation of S6K1 at Thr389 in both cell lines in response to H-89. Given that the Dami and CMK cell lines were derived from patients with acute megakaryocytic leukemia (AMKL) and expressed high levels of platelet-specific antigens, our data suggested that SP600125-induced polyploidization is cell-type specific, that these cell lines were more differentiated, and that phosphorylation at Thr421/Ser424 and dephosphorylation at Thr389 of S6K1 may play an important role in the SP600125-induced polyploidization of these cell lines synergistically with other signaling pathways. [ABSTRACT FROM AUTHOR]

Asymptotic expansion of singular integrals is presented for the study of the existence and uniqueness of spiky steady states of Keller-Segel's minimal chemotaxis model. A tool is developed to find asymptotic expansion of eigenpairs of a nonlocal singular eigenvalue problem arising from the study of stability of the spiky steady state. New insights are given to simplify significantly the proofs of the main results in [1]. [ABSTRACT FROM AUTHOR]

Using modeling approach of the complex network to construct a supply chain network model, this paper has mainly studied the problem of disruption risk control of supply chain under the background of globalization. The simulation result of the supply chain network model showed that the supply chain network is scale-free. The key nodes in the supply chain network can be identified by calculating the centrality of the nodes. Detailed results demonstrated that the ability of resist disruption risks and the network resilience of a supply chain can be improved by adding redundancy of the supply chain network and keeping a high level of collaborative working of the key suppliers. [ABSTRACT FROM AUTHOR]

Abstract: Implant-associated infection is a serious problem in orthopaedic surgery. One of the most effective ways is to introduce a controlled antibiotics delivery system into the bone filling materials, achieving sustained release of antibiotics in the local sites of bone defects. In the present work, mesoporous carbonated hydroxyapatite microspheres (MCHMs) loaded with gentamicin have been fabricated according to the following stages: (i) the preparation of the MCHMs by hydrothermal method using calcium carbonate microspheres as sacrificial templates, and (ii) loading gentamicin into the MCHMs. The MCHMs exhibit the 3D hierarchical nanostructures constructed by nanoplates as building blocks with mesopores and macropores, which make them have the higher drug loading efficiency of 70–75% than the conventional hydroxyapatite particles (HAPs) of 20–25%. The gentamicin-loaded MCHMs display the sustained drug release property, and the controlled release of gentamicin can minimize significantly bacterial adhesion and prevent biofilm formation against S. epidermidis. The biocompatibility tests by using human bone marrow stromal cells (hBMSCs) as cell models indicate that the gentamicin-loaded MCHMs have as excellent biocompatibility as the HAPs, and the dose of the released gentamicin from the MCHMs has no toxic effects on the hBMSCs. Hence, the gentamicin-loaded MCHMs can be served as a simple, non-toxic and controlled drug delivery system to treat bone infections. [Copyright &y& Elsevier]

Abstract: We present the results of a systematic study of chemical vapor deposition of graphene on silicon substrates. The silicon substrate is covered with SiO2 and capped with an electron-beam evaporator deposited nickel film, which serves as the catalyst for carbon precursor decomposition. Methane is used as the carbon precursor. Three key parameters of CVD growths, the growth temperature, time, and the post-growth cooling rate are studied and the optimized combination of the three allowed for the reproducible fabrication of single layer graphene of larger than 100μm2 covering more than 50% of the surface of 1-in. diameter Si wafers. We further demonstrate the transfer of CVD graphene onto SiO2/Si surfaces with higher than 95% success rate. Our result together with those reported by other research groups shows real promise of the integration of carbon electronics with silicon integrated circuit technology. [Copyright &y& Elsevier]

Abstract: Mesoporous carbonated hydroxyapatite microspheres (MCHMs) with a particle size of ∼5μm have been fabricated hydrothermally by soaking calcium carbonate microspheres (CCMs) in a disodium hydrogen phosphate solution at 140°C. The transformation mechanism is a dissolution–precipitation reaction. After soaking in the disodium hydrogen phosphate solution, the calcium ions released from the CCMs react with phosphate ions in the solution to form carbonated hydroxyapatite nanoparticles. These nanoparticles aggregate to form mesopores with the pore size of 4.0–14.0nm. The MCHMs have been tested as vancomycin delivery systems due to the presence of the OH units in the carbonated hydroxyapatite structure, which provide these carriers of great affinity towards host drug molecules. In addition, in vitro tests into a simulated body fluid (SBF) demonstrate that the MCHMs are bioactive, since an apatite layer deposits on their surfaces after 3days of assay. Such MCHMs could be useful in developing new biomaterials and have potential use in implanting and drug delivery for tissue regeneration. [Copyright &y& Elsevier]

The heavy metal (HM) ion-enzyme interaction is an important research topic in many areas. Using glucose oxidase (GOx) as an example, a comprehensive experimental platform based on quartz crystal microbalance and electroanalysis techniques is developed here to quantitatively study the HM ion-enzyme interactions and amperometric inhibitive assays of HM ions. The effects of some common HM ions on the bioactivities of solution-state GOx (GOxs), electrode surface-adsorbed GOx (GOxads), and polymer-entrapped GOx (GOxe) are comparatively examined on the basis of anodic amperometric detection of enzymatically generated H2O2. Ag+ shows the strongest inhibition effect among the HM ions examined, and the inhibitive assays of Ag+ based on GOxs, GOxads, and GOxe entrapped in poly(l-noradrenalin) (PNA) give limits of detection (LOD) of 2.0, 8.0, and 5.0 nM (S/N = 3), respectively. Inhibition effects of Hg2+, Cu2+, and Co2+ are detectable only at 15 μM or higher concentrations, and the other HM ions show undetectable inhibition even at 1.0 mM. The developed experimental platform allows one to quantify the number of the bound HM ions per GOxads molecule at various inhibition percentages. In addition, the electrosynthesized PNA matrix to entrap GOx for an inhibitive assay of Ag+ shows the lowest competitive affinity to HM ions and gives the highest sensitivity, as compared with several other polymer matrixes commonly used for the inhibitive assay. The suggested experimental platform is recommended for wide applications in enzymatic inhibitive assays and quantitative studies of the inhibition effects of HM ions on many other redox-event-relevant enzymes. [ABSTRACT FROM AUTHOR]

Abstract: Mesoporous titania coatings (MTCs) with a pore size of 4.75nm were prepared on Ti6Al4V substrates by a sol–gel process, and then irradiated with UV light at room temperature for 2h. The effects of mesoporous structure and UV irradiation on the in vitro bioactivity were investigated. Simulated body fluid (SBF) tests reveal that the MTCs exhibit a high apatite-forming ability, which may be attributed to the following reasons: (i) the BET surface area of the MTCs is ∼190m2/g, resulting in a greater density of Ti–OH groups than that without mesoporous structure; (ii) theoretical analysis reveals that the mesoporous structure can improve the driving force and nucleation rate of apatite precipitation in SBF. As compared with the MTCs, the UV-irradiated coatings do not exhibit any change in phase components and surface morphologies. However, the apatite-forming ability is higher on the UV irradiation coatings than on the MTCs because of the increase of Ti–OH groups and the improvement of wettability after UV irradiation. In addition, the investigation of the MG63 cell proliferation on the both substrates was performed. The results indicate that the MTCs before and after UV irradiation exhibit a good biocompatibility and are fit for the MG63 cell proliferation. [Copyright &y& Elsevier]

Abstract: Monodisperse mesoporous hydroxycarbonate apatite microspheres (MHAMs) were fabricated by soaking calcium carbonate microspheres (CCMs) in a cetyltrimethylammonium bromide (CTAB)/Na2HPO4/cyclohexane/n-butanol emulsion system. After soaking CCMs in the emulsion system at 20°C, hydroxycarbonate apatite nanocrystals nucleate heterogeneously on the surfaces of CCMs via a dissolution–precipitation reaction. The as-formed nanocrystals aggregate to form mesopores with the pore size of ∼3.9nm and ∼9.0nm. The smaller mesopores are derived from the direct aggregation of the nanocrystals, which do not change obviously with the reaction time. In contrast, the larger mesopores are formed by using CTAB micelles as templates, and their pore size decreases from ∼9.0nm to ∼7.4nm with increasing the reaction time from 6h to 1day. After reaction for 3 or 5days, the larger mesopores disappear because of unstability of the CTAB micelles. If reaction temperature is kept at 50°C, the conversion rate of CCMs to MHAMs is greater than that at 20°C, and the corresponding mesoporous structure is unimodal with the pore size of ∼3.9nm. Simulated body fluid immersion tests reveal that MHAMs have a great in vitro bioactivity, which is attributed to the mesoporous structure and B-type CO3 2− substitution of MHAMs. [Copyright &y& Elsevier]

Magnetic mesoporous carbonated hydroxyapatite microspheres have been fabricated hydrothermally by using CaCO3/Fe3O4microspheres as sacrificial templates. The high drug-loading capacity and sustained drug release property suggest that the multifunctional microspheres have great potentials for bone-implantable drug-delivery applications. [ABSTRACT FROM AUTHOR]