Photocatalytic decomposition of VOCs by AC–TiO2 and EG–TiO2 nanocomposites

Clean Technologies and Environmental Policy - In this study, TiO2 nanoparticles (NPs)-based catalysts were prepared for the photocatalytic removal of toluene as a model VOC from air under UV light....     

Investigation of Magnetic and Structural Properties of Amorphous Alloys Irradiated by Nd:YAG Laser

Amorphous metallic alloys (AMAS) have found wide application in various fields. Laser is used to modify materials. In this work, we have prepared an amorphous metallic alloy with composition Fe₇₇Co₂₁Si₂ using the melt spinning method. The prepared specimens have irradiated by a Nd:YAG laser at 1064?nm, with various fluences to investigate the corresponding induced change. The structures of specimens are verified by X-ray diffraction (XRD) before and after laser irradiated. Then magnetic parameters are measured using a vibrating sample magnetometer. Morphology reference and laser treated samples are investigated by the scanning electron microscope (SEM). The use of laser beam of relatively low energy, but with a subsequent overlapping of heated areas, resulted in a much more homogeneous structure in the heated areas of the ribbon. These measurements show that initially the magnetic properties are altered due to laser processing. The surface alteration was being simultaneously monitored by laser induced breakdown spectroscopy (LIBS).     

Microparticles containing erlotinib-loaded solid lipid nanoparticles for treatment of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) patients with sensitizing mutations in the exons 18–21 of the epithelial growth factor receptor (EGFR) gene show increased kinase activity of EGFR. Hence, tyrosine kinase inhibitors (TKIs) such as erlotinib (ETB) have commonly been used as the second line therapeutic option for the treatment of metastatic NSCLC. While the ETB is available as an oral dosage form, the local delivery of this TKI to the diseased cells of the lung may ameliorate its therapeutic impacts. In the current study, we report on the development of ETB-loaded solid lipid nanoparticle (SLN) based formulation of dry powder inhaler (ETB-SLN DPI). ETB-SLNs were formulated using designated amount of compritol/poloxamer 407. The engineered ETB-SLNs showed sub-100?nm spherical shape with an encapsulation efficiency of 78.21%. MTT assay and DAPI staining revealed that the ETB-SLNs enhanced the cytotoxicity of cargo drug molecules in the human alveolar adenocarcinoma epithelial A549 cells as a model for NSCLC. To attain the ETB-SLN DPI, the ETB-SLNs were efficiently spray dried into microparticles (1–5?μm) along with mannitol. The ETB-SLN DPI powder displayed suitable flowability and aerodynamic traits. The Carr's Index, Hausner ratio and Next Generation Impactor (NGI) analyses confirmed deep inhalation pattern of the formulation. Based on these findings, we propose the ETB-SLN DPI as a promising treatment modality for the NSCLC patients.     

Investigation of the ceramifying process of modified silicone–silicate compositions

Glass frits were added into silicone-based composites with the aim to improve low temperature ceramification at elevated temperatures. The effect of glass frits on the properties of ceramic residue is investigated. Field emission scanning electron microscopy (FESEM), electron probe microchemical analysis (EPMA) and X-ray diffraction analysis (XRD) showed that glass frits reacted via a eutectic reaction with mica and silica. Electrical conductivity measurements at elevated temperatures showed a decline in volume resistivity with glass frit addition. It was concluded that increased conductivity is a result of ionic conduction of the glass phase produced by eutectic reactions between frits, silica and mica at high temperatures. Thermal mechanical analysis (TMA) was used to explore the dimensional changes of these composites during programmed heat treatment.     

Laser-assisted preparation of C3N4/Fe2O3/Au nanocomposite: a magnetic reusable catalyst for pollutant degradation

Clean Technologies and Environmental Policy - Assorted common contaminants namely organic dyes and nitro compounds are generated by various industries and have caused alarming problems for the...     

Microchemical and microstructural investigations of degradation in asbestos-cement sheet

The physical and chemical transformations occurring in asbestos cement (A/C) sheet following a two-year natural exposure to sulfate rich water in a cooling tower have been investigated using a combination of analytical and microstructural techniques. The investigation was conducted on a reference A/C sheet, specimens of the partially degraded A/C sheet and chrysotile fibers recovered from the latter. The methods employed included X-ray diffraction, scanning electron microscopy and EDXA, thermogravimetry, infrared spectroscopy and evolved gas analysis during thermal decomposition. Analysis of the combined data conclusively show that the primary cause of degradation and delamination of the A/C sheet is the formation of gypsum (CaSO₄)·2H₂O crystals which is accompanied by substantial volume expansion. Apparently, carbonation, yielding calcite and/or vaterite crystals, is a secondary degradation mechanism.     

Novel dental nanocomposites: fabrication and investigation of their physicochemical,mechanical and biological properties

The aim of this study was to investigate biological, physicochemical and mechanical characteristics of a series of novel dental restorative nanocomposites that comprise dendritic methacrylate end-caped monomers, triethylene glycol dimethacrylate (TEGDMA; as diluting monomer) and modified silica nanoparticles (\(\hbox {M-SiO}_{2}\); as inorganic filler). The cytotoxicity effects of the monomers and fabricated nanocomposites were examined against NIH3T3 cells (the standard fibroblast cell line) through MTT and trypan blue cell viability tests, respectively. The antibacterial activities of the monomers were evaluated against Lactobacillus plantarum by standard agar disk diffusion approach. The mechanical properties (flexural strength (FS) and compressive strength (CS)) as well as some physicochemical characteristics such as water sorption (WS), sol fraction (SF) and double bond conversion (DC) were also investigated, and compared with corresponding characteristics of 3M Filtek Z250 as a reference. Thus, the fabricated nanocomposites have potential as dental restorative materials mainly due to their suitable biological, physicochemical and mechanical properties.     

Synthesis,in vitro characterization,and anti-tumor effects of novel polystyrene-poly(amide-ether-ester-imide) co-polymeric micelles for delivery of docetaxel in breast cancer in Balb/C mice

Objective: The goal of the present work was to make novel co-polymeric micellar carriers for the delivery of docetaxel (DTX).

Significance: Co-polymeric micelles can not only solubilize DTX and eliminate the need for toxic surfactants to dissolve it, but also cause passive targeting of the drug to the tumor and reduce its toxic side effects.

Methods: Poly(styrene-maleic acid) (SMA) was conjugated to poly (amide-ether-ester-imide)-poly ethylene glycol (PAEEI-PEG). Copolymer synthesis was proven by Fourier transform infrared (FTIR) and ¹H-nuclear magnetic resonance (¹H-NMR). The SMA-PAEEI-PEG micelles loaded with DTX were prepared and their critical micelle concentration (CMC), zeta potential, particle size, entrapment efficiency, and their release efficiency were studied. MCF-7 and MDA-MB231 breast cancer cells were used to evaluate the cellular uptake and cytotoxicity of the micelles. The antitumor activity of the DTX-loaded nanomicelles was measured in Balb/c mice.

Results: The FTIR and HNMR spectroscopy confirmed successful conjugation of SMA and PAEEI-PEG. The drug loading efficiency was in the range of 34.01–72.75% and drug release lasted for 120?h. The CMC value of the micelles was affected by the SMA/PAEEI-PEG ratio and was in the range of 29.85–14.28?µg/ml. The DTX-loaded micelles showed five times more cytotoxicity than the free drug. The DTX loaded micelles were more effective in tumor growth suppression in vivo and the animals showed an enhanced rate of survival.

Conclusion: The results show that the SMA-PAEEI-PEG micelles of DTX could potentially provide a suitable parenteral formulation with more stability, higher cytotoxicity, and improved antitumor activity.     

Hydrophilicity and morphological investigation of polycarbonate irradiated by ArF excimer laser

Lasers are used to modify polymeric materials. In this work, a number of polycarbonate (PC) pieces were exposed by ArF excimer laser, 193 nm, at various UV doses from 10 to 100 J/cm² with 50-500 mJ/pulse at 10 Hz pulse repetition rate. Morphology of PC has been investigated by scanning electron microscope (SEM) at three regimes pre-ablation, slow and fast ablation. SEM identifies that the conical defects are created on the polymer surface to grow opposite to the direction of laser irradiation. It increases the superficial absorptivity of the material dependent on the ArF laser induced conical microstructure geometry. The contact angle measurement was performed here, in order to determine the hydrophilicity of the irradiated polymer at various coherent doses. It is shown that the contact angle of PC samples which are exposed to the ArF laser significantly alters with UV dose below 7 J/cm².