RSC Advances

Pizarro, A. H.; Molina, C. B.; Rodriguez, J. J.

doi: 10.1039/c6ra24542kpmid: N/A

Catalytic hydrotreatment of synthetic dyes as azo compounds and triarylmethanes has been carried out under ambient-like conditions (25–50 °C, 1 atm) with H2 using Pd supported on Al-pillared clays and Al2O3 as catalysts. The treatment leads to complete decoloration of aqueous solutions of the azo dyes (azobenzene, methyl orange, Congo red and oil red) due to the catalytic hydrogenation of the NN bonds. Under acid pH the color removal was enhanced and a solid residue was formed in the case of Congo red, being completely removed. With aqueous solutions of the triarylmethane dyes crystal violet, fuchsine and malachite green complete decoloration was also achieved upon hydrogenation of the chromophore groups or modification of the chemical structure.

Zhang, Hongjiang; Zhang, Chong; Wang, Xunchang; Qiu, Zexiong; Liang, Xinmiao; Chen, Bing; Xu, Jiawei; Jiang, Jia-Xing; Li, Yuda; Li, Hui; Wang, Feng

doi: 10.1039/c6ra20765kpmid: N/A

A series of microporous organic polymers (MOPs) based on tetraethynyl monomers such as tetrakis(4-ethynylphenyl)methane and tetrakis(4-ethynylphenyl)silane was synthesized via conventional Sonogashira–Hagihara coupling reaction. The resulting MOPs were characterized by thermogravimetric analyses, IR-spectra, scanning electron microscopies, and the Brunauer–Emmett–Teller (BET) method. The incorporation of triphenylamine or azobenzene moieties into the polymer skeleton increases the number of electron donating basic nitrogen sites in the porous frameworks. Thus, these MOPs could exhibit efficient adsorption of Lewis acidic CO2 molecules and display good CO2-over-N2 selectivity. The triphenylamine-based polymer, TEPM-TPA, shows a high BET specific surface area up to 1072 m2 g−1 with a moderate CO2 uptake capacity of 2.41 mmol g−1 at 273 K and 1.13 bar. As for separation of CO2, both TEPM-Azo and TEPS-Azo exhibit relatively high CO2-over-N2 selectivities of 70.8 and 64.7 at 273 K, respectively, due to the N2-phobic feature of azo-based polymers.

Wang, Langlang; Wang, Xueqian; Jing, Xuli; Ning, Ping

doi: 10.1039/c6ra21715jpmid: N/A

The hydrogen cyanide (HCN) removal efficiency of activated carbon modified with different metal was studied under low oxygen conditions. When activated carbon was modified with Cu(NO)3, cobalt sulfonated phthalocyanine (CoSPc) and Ce(NO3)3·6H2O, its catalytic efficiency in HCN removal was significantly enhanced with the optimal conditions of 400 °C as the calcination temperature, 10% relative humidity and 1% oxygen concentration. And the catalytic hydrolysis and oxidation efficiency of AC–Cu–CoSPc–Ce was more than 98% at 200–350 °C with the maximum selectivity to N2 of 52.6% at 300 °C. Although both AC–Cu and AC–Cu–CoSPc–Ce catalysts were reliable and stable, AC–Cu–CoSPc–Ce had a better catalytic activity at lower temperature. According to BET and X-ray photoelectron spectroscopy (XPS) results, Cu was mainly in the form of CuO and Cu2O, Co was present in the form of Co2+ and Co0, and Ce was mainly in the form of CeO2 and Ce2O3 on the catalyst surface. The reaction pathways were proposed.

Zolfagharinia, Somayeh; Koukabi, Nadiya; Kolvari, Eskandar

doi: 10.1039/c6ra22791kpmid: N/A

Although glass recycling has been conducted since 1970s, and even though recycled glass waste has been used in the construction of various alternative products, the utilization of glass waste for catalytic applications has not been fully considered until now. In the present work, glass waste materials were demonstrated to be accessible, convenient, and inexpensive resources as catalyst supports for the immobilization of sulfonic groups on their surfaces to produce an efficient heterogeneous solid acid nanocatalyst, the so-called nano-glass-waste-supported sulfonic acid (n-glass-waste-SO3H (n-GW-SA)). Titration and XRD, FE-SEM, EDX, FT-IR, BET, BJH, TEM, and TGA analysis techniques were employed to fully characterize the as-prepared catalyst. The glass-waste-supported sulfonic acid exhibited superior catalytic performance in multicomponent reactions (MCRs) for the one-pot synthesis of biologically useful 3,4-dihydropyrimidin-2(1H)-ones and xanthene derivatives in high to excellent yields. The eco-friendly and economic advantages of the said catalyst include its good recoverability and reusability for several runs, low price, low toxicity, and facile accessibility, manufacture, and handling.

Jana, Soumen; Hennessy, Rebecca; Franchi, Federico; Young, Melissa; Hennessy, Ryan; Lerman, Amir

doi: 10.1039/c6ra24282kpmid: N/A

Regeneration of heart valves depends on the regeneration of cells residing in the heart valve leaflet, i.e., valvular interstitial cells (VICs). In this study, the regeneration capacity of VICs obtained from healthy and diseased valves of patients with various ages and genders were investigated. The cells obtained from the valves were cultured in vitro for 21 days on our developed standalone nanofibrous substrates. The substrates were pliable. Proliferation of cells, their morphologies, collagen deposition, and gene and protein expression were assayed to compare their regeneration capacity. VICs from healthy valves exhibited higher proliferation and cell spreading in comparison to VICs from diseased valves. However, collagen deposition by VICs from diseased valves was higher compared to the deposition by VICs from healthy valves, irrespective of age and gender of the patients. VICs on nanofibrous substrates showed high vimentin and collagen type I expression; expression of α-SMA showed the reverse trend demonstrating the importance of nanofibers in heart valve tissue engineering and regeneration. Although variations in proliferation, gene, and protein expression of VICs from healthy and diseased valves of patients with various ages and genders were observed, they were not statistically significant. Thus, VICs from a diseased valve maintain the potential to regenerate in a non-degenerative environment, providing an opportunity for tissue engineering of diseased valves.

Agarwal, Sankalp; Morshed, Muhammad; Labour, Marie-Noelle; Hoey, David; Duffy, Brendan; Curtin, James; Jaiswal, Swarna

doi: 10.1039/c6ra24382gpmid: N/A

This paper reports a multi-step procedure to fabricate a novel corrosion resistant and biocompatible PLGA–silane coating on the magnesium (Mg) alloy AZ31. The first step involves alkaline passivation followed by dip coating in a methyltriethoxysilane (MTES) and tetraethoxysilane (TEOS) mixture to produce a cross-linked siloxane coating. The second step is to impart an amine functionalization to the silane modified surface by using 3-aminopropyl-triethoxy silane (APTES) for promoting adhesion of the acid terminated poly-(lactic-co-glycolic) acid (PLGA) as a final coating step. Static contact angle measurements, Fourier transform infrared spectroscopy and scanning electron microscopy analysis confirmed the successful assembly of coatings on the AZ31 Mg alloy. Potentiodynamic polarization and impedance spectroscopy studies showed the improved initial corrosion resistance of the coated AZ31 substrate. Measurements of magnesium ion release, pH changes and hydrogen evolution showed enhanced corrosion protection of coated substrate over uncoated AZ31 alloy for 21 and 14 days respectively. The MTT assay, live–dead cells staining, DNA quantification and alkaline phosphatase activity assay were used to measure the biocompatibility, proliferation and differentiation of MC3T3-E1 osteoblast cells. Scanning electron microscopy was used to observe cell morphology and integration with the coated surface. The coated substrate showed improved cytocompatibility as compared to the uncoated AZ31 alloy surface. The application of such coatings on biodegradable Mg alloys enhanced their corrosion resistance and biocompatibility. An additional advantage is that the coating also served as a potential delivery vehicle for specific drugs and bio-active molecules releasing from an implant surface as the coatings, such as PLGA, adapt during the corrosion process, thereby enhancing bone regeneration.

Liu, Jian; McCarthy, Danielle L.; Tong, Linyue; Cowan, Michael J.; Kinsley, John M.; Sonnenberg, Laura; Skorenko, Kenneth H.; Boyer, Steven M.; DeCoste, Jared B.; Bernier, William E.; Jones, Wayne E.

doi: 10.1039/c6ra22797jpmid: N/A

Pharmaceuticals and personal care products are commonly discarded into environmental waters through sewers with human waste or by direct disposal causing serious contamination. Photocatalytic degradation of phenazopyridine (PAP) as a model pharmaceutical contaminant was investigated using TiO2 nanofibers and hybrid PEDOT infused TiO2 nanofibers. A novel material of PEDOT infused TiO2 nanofibers was fabricated via electrospinning and calcination to form TiO2 followed by the introduction of PEDOT using vapor phase polymerization. By changing the calcination temperature, the phase composition in TiO2 nanofibers can be adjusted to pure anatase phase, mixed phase and pure rutile phase. The photocatalytic activities of TiO2 nanofibers before and after PEDOT polymerization were measured by monitoring the decreasing concentration of PAP in aqueous solution under UV illumination using UV-Vis absorption spectroscopy. PEDOT infused TiO2 nanofibers showed an improved photocatalytic performance compared to their non-PEDOT infused counterparts for the degradation of PAP. This improvement can be attributed to the introduction of hole transport layer of PEDOT leading to an enhanced hole transfer from the TiO2 nanofibers to PEDOT. PEDOT infused rutile nanofiber has the most degradation enhancement (125%) compared to other two types of fibers (70% for PEDOT infused anatase & 30% for PEDOT infused mixed-phase).

Zhang, Kun; Wang, Xiaofeng; Guan, Fangxia; Li, Qian; Li, Jingan

doi: 10.1039/c6ra17584hpmid: N/A

Ophiopogonin D, a traditional Chinese medicinal ingredient, was immobilized to form a coating onto the surface of 316L stainless steel (316L SS), which is often used in cardiovascular implant materials, and evaluated for its endothelialization ability in vitro. The immobilized coating showed more hydrophilic property compared with the 316L SS control, contributing to protein absorption and cell spreading. A CCK-8 assay was performed to investigate the attachment and proliferation of vascular endothelial cells (VEC) onto the coating, and the results showed that there were more VEC on the Ophiopogonin D coating than on the 316L SS surface. The acridine orange (AO)/propidium iodide (PI) staining images of the VEC proved that the Ophiopogonin D coating could effectively inhibit VEC apoptosis, compared with the control. In addition, VEC on the Ophiopogonin D coating released more nitric oxide (NO) and PGI2 compared with VEC on the 316L SS. All the results indicated that Ophiopogonin D could significantly improve surface endothelialization and possessed potential applications for the surface modification of cardiovascular devices.

Horikoshi, Satoshi; Yamazaki, Satoshi; Narita, Atsushi; Mitani, Tomohiko; Shinohara, Naoki; Serpone, Nick

doi: 10.1039/c6ra20518fpmid: N/A

A novel phased array antenna system was tested for use in microwave-assisted organic syntheses under waveguideless and applicatorless setup conditions with the synthesis of the ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) as an example; 5.8 GHz microwaves were used to irradiate the sample through free space a distance of 5 m from the antenna system.

Xu, Zhuo; Li, Yangping; Liu, Zhengtang

doi: 10.1039/c6ra09229bpmid: N/A

The structural, electronic, and thermodynamic properties of a monolayer honeycomb Si1−xGexC sheet are analyzed using first-principles calculations based on density functional theory. The dynamical stability of our structures is testified by the analysis of phonon dispersion curves. Deviations of the lattice parameter, Young's modulus, and band gap of relaxed structures derived from Vegard's law are investigated; small bowing coefficients are observed except for Young's modulus. The band gaps are found to decrease as the concentration x increases. The T–x phase diagram, which identifies the stable, metastable, and unstable mixing areas, is also calculated and shows a critical temperature Tc of 187.45 K. The results provide a new method to modify the electronic properties of 2D-SiC, which has great importance in its applications for optoelectronic devices.