Improving the Antibacterial Property of Polyethylene Terephthalate by Cold Plasma Treatment

Many studies suggest strong hydrophilicity of plasma treated polyester surfaces. However, no studies have been reported on the influence of plasma on the antibacterial activity of polyethylene terephthalate. First samples were padded with triclosan as antibacterial agent with different concentrations. Second samples were treated by oxygen plasma with different operating frequency and treating time, respectively. Afterwards, plasma treated samples were padded with triclosan in same conditions. The results revealed that the antibacterial activity slighlty increased after treating with triclosan. SEM images and FTIR spectra showed that horizontal channels were brought about on the fiber surface and then better surface roughness and wettability were obtained by plasma. Fibers were fully coated with triclosan after plasma and the antibacterial activity increased with increasing operating frequency and reaction time. Finally, the samples treated with triclosan after plasma gave acceptable results and showed the best antibacterial activity for Staphylococcus aureus and Escherichia coli.     

The removal of chlorinated organic herbicide in water by gamma-irradiation

In this study, the radiation-induced degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide in aqueous solution was studied under various conditions as a function of irradiation dose in the absence and presence of hydrogen peroxide. The obtained data confirmed that largest yield of radiolytic degradation is obtained in oxidation processes/ionizing radiation, where oxidation is carried out with hydroxyl radicals. For complete degradation of 50?ppm 2,4-D, a required dose was lower in the presence of hydrogen peroxide. The formed major toxic phenolic intermediates were 2,4-dichlorophenol (2,4-DCP) and 4-chlorophenol (4-CP). The chemical analysis of the 2,4-D and the intermediates resulted from the radiolytic degradation were performed using a gas chromatography associated to mass spectrometry (GC?CMS) with ion trap dedector (ITD) and ion chromatography (IC). The formation of chlorophenols in addition to chloride, formaldehyde and carboxylic acids was studied as a function of absorbed dose.     

Ethynyl-bridged porphyrin-corrole dyads and triads: Synthesis,properties and DFT calculations

Ethynyl-bridged porphyrin-corrole dyads and triads were synthesized by using Pd(0) mediated coupling reactions and their structures were characterized by NMR, FT-IR, UV/Vis and fluorescence techniques. Besides spectroscopic techniques, computational studies at B3LYP/6-311G(d,p) level of DFT were also used to elucidate the minimum energy geometries and the molecular orbital characteristics of the new dyads and triads. DFT calculations pointed out the presence of charge separated donor-acceptor property between macrocycles of dyads and triads, and the emission studies indicated an excited state interaction between macrocycles, and energy transfer from the porphyrin to the corrole unit.     

Density functional theory study of interactions between carbon dioxide and functionalized polyhedral oligomeric silsesquioxanes

Polyhedral Oligomeric Silsesquioxanes (POSS) are cage‐structured inorganic–organic hybrid materials which can be used in various industrial applications. It is recently discovered that POSS structures with certain functional groups can be solubilized in supercritical CO₂ allowing their applications in environmentally benign supercritical processing of materials. In this theoretical study, nature and energetics of the interactions of octatrifluoropropyl POSS, octatrifluoromethyl POSS, and octamethyl POSS with CO₂ are investigated according to the principles of density functional theory (DFT) by use of Gaussian 09 software. Simulations show that CO₂‐octamethyl POSS pair has hydrogen bonding between the O atom of CO₂ and the H atom of the methyl group, and CO₂‐octatrifluoromethyl POSS pair has interactions between the C atom of CO₂ and the F atom of the trifluoromethyl group. CO₂‐octatrifluoropropyl POSS pair is found to have both interaction types. The octamethyl, the octatrifluoromethyl and the octatrifluoropropyl POSS structures have interaction energies of ?2.18 kcal/mol, ?3.10 kcal/mol, and ?3.77 kcal/mol, respectively. This shows that the presence of Lewis acid–Lewis base interaction between C and F instead of hydrogen bonding between O and H atoms enhances the interaction of the molecule with CO₂, while the presence of both interactions between the octatrifluoropropyl POSS‐CO₂ pair makes the intermolecular interaction even stronger.     

Effect of irradiation on ethyl 2‐amino‐4,5,6,7‐tetrahydrobenzo[b]thiophene‐3‐carboxylate: an ESR study

Ethyl 2‐amino‐4,5,6,7‐tetrahydrobenzo[b]thiophene‐3‐carboxylate [C₁₁H₁₅NO₂S] was synthesized by the Gewald method. Its single crystals were grown from an alcohol/ethyl acetate solution at 15 °C and characterized using IR and ¹H‐NMR. These single crystals were irradiated for 72 h at 298 K by a ⁶⁰Co gamma source with a dose speed of 0.864 kGy/h. After irradiation, electron spin resonance (ESR) measurements were carried out to study radiation‐induced radicals in the temperature range from 120 to 450 K. Additionally, for the single crystal, ESR angular dependencies were measured in the xy, xz and yz planes of the substance. This irradiated single crystal was analyzed based on the ESR spectra. Analysis of the spectra revealed that the radical was formed by a C–H bond fission at the carbon end of the substance. It was also observed that the color of the sample changed after irradiation. The hyperfine and g parameters were determined from the experimental spectra. It was inferred from these results that the hyperfine parameters and g value exhibited anisotropic behavior. The average values of these parameters were calculated as follows: g = 2.0088, A_H1=H2 = 20.70 G, A_H3=H4 = 10.80 G, A_Ha = 4.59 G, A_Hb = 3.24 G and, A_N = 6.10 G. Copyright © 2011 John Wiley & Sons, Ltd.     

Adaptive network fuzzy inference system modeling for the input selection and prediction of anaerobic digestion effluent quality

This paper presents the development and evaluation of three adaptive network fuzzy inference system (ANFIS) models for a laboratory scale anaerobic digestion system outputs with varied input selection approaches. The aim was the investigation of feasibility of the approach-based-control system for the prediction of effluent quality from a sequential upflow anaerobic sludge bed reactor (UASBR) system that produced a strong nonlinearship between its inputs and outputs. As ANFIS demonstrated its ability to construct any nonlinear function with multiple inputs and outputs in many applications, its estimating performance was investigated for a complex wastewater treatment process at increasing organic loading rates from 1.1 to 5.5 g COD/L d. Approximation of the ANFIS models was validated using correlation coefficient, MAPE and RMSE. ANFIS was successful to model unsteady data for pH and acceptable for COD within anaerobic digestion limits with multiple input structure. The prediction performance showed a high feasibility of the model-based-control system on the anaerobic digester system to produce an effluent amenable for a consecutive aerobic treatment unit.     

Modified iteration method for solving fractional gas dynamics equation

This paper is devoted to the time‐fractional gas dynamics equation with Caputo derivative. Fractional operators are very natural tools to model memory‐dependent phenomena. Modified iteration method is proposed to obtain the approximate and analytical solution of the fractional gas dynamics equation. This method is a combined form of the new iteration method and Laplace transform. Modified iteration method really is powerful and simple method compared with other methods. Existence and uniqueness of solution are proven. Numerical results for different cases of the equation are obtained. Copyright © 2016 John Wiley & Sons, Ltd.     

Encapsulation and release by star‐shaped block copolymers as unimolecular nanocontainers

A five‐arm star‐shaped poly(ethylene oxide) (PEO) with terminal bromide groups was used as a macroinitiator for the atom transfer radical polymerization of tert‐butyl acrylate (tBA), resulting in five‐arm star‐shaped poly(ethylene oxide)‐block‐poly(tert‐butyl acrylate) block copolymers. The polymerization proceeded in a controlled way using a copper(I)bromide/pentamethyl diethylenetriamine catalytic system in acetonitrile as solvent. The hydrolysis of the tBA blocks of the amphiphilic star‐shaped PEO‐b‐PtBA block copolymer resulted in dihydrophilic star structures. The encapsulation of the star‐block copolymers and their release properties in acid environment have been followed by UV‐spectroscopy and color changes, using the dye methyl orange as a hydrophilic guest molecule. Characterization of the structures has been done by ¹H NMR, size exclusion chromatography, MALDI‐TOF, and differential scanning calorimetry. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 650–660, 2008     

Capillary Electrophoretic Determination of Citalopram in Pharmaceutical Tablets and Serum

Determination of citalopram by capillary electrophoresis is described. Compounds were separated at 28 kV in 75 μm i.d. fused silica capillary tubing (total length 85 cm, effective length 65 cm) with 10 mM borate buffer, pH 8.5, containing 10% (v/v) methanol as running buffer. Citalopram and propylparaben (IS) appeared at 3.5 and 5.5 min, respectively. Repeatable linear results were obtained. The limits of detection and quantification were 5.73 × 10⁻⁶ and 1.72 × 10⁻⁵ M, respectively. When citalopram was determined in a pharmaceutical tablet by capillary electrophoresis and by a UV-spectrophotometric method differences between the results were not significant. The citalopram content of tablets was 100.8 ± 2.95% of the label claim. The amount found in serum was 26.7 ± 0.1% of the free drug, indicating that 73.3% of the drug was bound to protein.