Synthesis and antimicrobial activity of metronidazole containing polymer and copolymers

Homopolymer and copolymers containing metronidazole (MTZ) drug were synthesized. Acryloyl chloride was reacted with MTZ (drug) to produce monomer containing MTZ, and then the monomer was copolymerized with various amounts of methyl methacrylate. The produced monomer, homopolymer, and copolymers were characterized by elemental analysis, IR, and ¹H‐NMR. The antimicrobial activities of the synthesized polymers were tested against Kelpsilic as fungal organisms, and Escherichia coli, Bacillus subitilus, and Pesudomonus areuginosa as bacteria organisms. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of demineralization and heating rate on the pyrolysis kinetics of Jordanian oil shales

The effect of mineral matter content on the activation energy of oil shale pyrolysis has been studied. Kerogen was isolated from raw oil shale by sequential HCl and HCl/HF digestion. Oil shale and kerogen samples were pyrolyzed in a Thermogravimetric Analyzer at different heating rates (1, 3, 5, 10, 30, and 50 °C/min) up to a temperature of 1000 °C. Total mass loss of all oil shale samples remained almost constant irrespective of the heating rate employed, whereas it decreased with the increase of heating rate for kerogen (74.5 to 71.4%). From the pyrolysis profile activation energy (Ea) was found to vary between 70 and 83 kJ/mol for oil shale, while 82-112 kJ/mol has been determined for isolated kerogen. An increase of both Ea and pre-exponential factor was observed with an increasing heating rate. It is concluded that the mineral matter in oil shale enhances catalytic cracking as is evident from the reduced Ea values of oil shale compared with those for kerogen.     

Oil shale pyrolysis kinetics and variable activation energy principle

A modified first order kinetic equation with variable activation energy is employed to model the total weight loss of Ellajjun oil shale samples. Fixed bed retort with 400 g of oil shale sample size is used in this study in 350–550 °C temperature range. Variable heating rate, h, in the range 2.6–5 °C min⁻¹ are tested.     

Intelligent and collaborative Multi-Agent System to generate and schedule production orders

The authors present a Multi-Agent System for constructing and releasing production orders. In a manufacturing enterprise, the generation of production orders consists in a set of coordinated tasks among departments. This has been achieved traditionally as a module of the Production Activity Control (PAC) system. However, classic PAC modules lack collaborative techniques and intelligent behaviour. Moreover, in real-life situations experienced planners take over traditional PAC systems, since the range of possibilities to actually build production orders increases exponentially. To contribute to production planning, we present an intelligent and collaborative Multi-Agent System (MAS), having coordinated two forms to emulate intelligence. The learning capability is achieved by means of a Feed-forward Artificial Neural Network (FANN) with the back-propagation algorithm. The FANN is embedded within a machine agent whose objective is to obtain the appropriate machine in order to comply with requirements coming from the sales department. Also, an expert system is provided to a tool agent, which in turn is in charge of inferring the right tooling. The MAS also consists of a coordinator and a spy. The coordinator agent has the responsibility to control the flow of messages among the agents, whereas the spy agent is constantly reading the Enterprise Information System. Finally, a scheduler agent schedules the production orders. The resultant MAS improves the current form to plan production in a factory dedicated to produce labels.     

Optimization of Focused Ultrasound Extraction (FUSE) and Supercritical Fluid Extraction (SFE) of Citrus Peel Volatile Oils and Antioxidants

In order to evaluate the use of citrus peel as a potential source of volatile oils and antioxidants in food industry, supercritical fluid extraction (SFE) and focused ultrasound extraction (FUSE) techniques have been thoroughly studied. Based on experimental designs and considering the extraction of monoterpenes among the volatile oils, the total phenol content, and the antioxidants, the most adequate extraction conditions have been defined for lemon and then applied to other citrus. The optimum SFE conditions for volatile oils and antioxidants were the following: pressure, 100 and 170 bar; temperature, 35 °C for both; flow, 1 mL/min in both cases; EtOH%, 0 and 40 %, respectively. FUSE extraction of the volatile oils was carried out with cyclohexane and the antioxidants with ethanol. The optimum instrumental conditions were roughly the same (extraction time 5 min, cycles 5 s^?1, and amplitude 30 % in both cases, and 10 and 15 mL, respectively, in the case of solvent volumes). Based on successive extractions, FUSE revealed a more efficient technique owing to the solvent features. Finally, a stability test of the content of aromas and antioxidant capacity was carried out and aromas were stable stored at 4 °C for 6 weeks and the antioxidant capacity, in the same conditions, for 13 weeks.     

Structural and morphological studies of zinc oxide incorporating single-walled carbon nanotubes as a nanocomposite thin film

Pure zinc-oxide and a composition of zinc oxide-single walled carbon nanotubes (ZnO-SWCNTs) thin films were prepared by using a sol–gel doctor blade technique. A precursor of zinc acetate dehydrate (Zn(CH₃COO)₂·2H₂O), absolute ethanol (C₂H₅OH) and triethanolamine were mixed in one solution. Non-acid treatment SWCNTs were doped in the prepared solution. Structural and morphological properties of ZnO and ZnO-SWCNTs thin films were studied by means of X-ray diffractometer (XRD), field-emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and transmission electron microscopy (TEM). XRD measurements indicated that the crystallite size of ZnO was bigger than the crystallite size of ZnO-SWCNTs; 0.4331 and 0.3386 nm, respectively. The FESEM images showed the hexagonal and nanorod structures of ZnO thin film and a broccoli-like ZnO nanostructures coated with CNTs for ZnO-SWCNTs thin film. The AFM analysis revealed smoother surface morphology of ZnO-SWCNTs thin film compared to the surface of pure ZnO thin film. TEM results captured the inner structures of ZnO and ZnO-SWCNTs. Inner and outer diameter of non-acid treatment SWCNTs were recorded about 5.09 and 14.95 nm, respectively. Photovoltaic performance of ZnO-SWCNTs based dye-sensitized solar cell (DSSC) showed high power conversion efficiency of 0.102 % compared to ZnO based DSSC (0.019 %). This study suggests that SWCNTs should be acid-treated to produce highly porous structure and greater surface area for better photovoltaic performance of the DSSCs.     

Solar energy in Malaysia: Current state and prospects

Malaysia is situated at the equatorial region with an average solar radiation of 400-600 MJ/m² per month. It has a promising potential to establish large scale solar power installations; however, solar energy is still at the infancy stage due to the high cost of photovoltaic (PV) cells and solar electricity tariff rate. The Malaysian government is keen to develop solar energy as one of the significant sources of energy in the country. According to the 9th Malaysia Plan (9MP), a large allocation had been dedicated for implementation of solar PV systems. On 25th July 2005, a Malaysian Building Integrated Photovoltaic (MBIPV) project had been announced and it was planned to end by 2010. The project consists of three categories which include: BIPV demonstration, national “SURIA1000” and BIPV showcase. Greater emphasis will be placed on energy efficiency under the Tenth Malaysia Plan (2011-2015). This paper discusses present and future situation of solar power in Malaysia, utilization of solar energy and the strategies taken by the Malaysian government and Non-Government Organizations (NGOs) to promote solar energy thermal applications and electricity power generation in the future.     

Effect of Hydrogen Peroxide on the Biosynthesis of Heme and Proteins: Potential Implications for the Partitioning of Glu-tRNAGlu between These Pathways

Glutamyl-tRNA (Glu-tRNA^Glu) is the common substrate for both protein translation and heme biosynthesis via the C₅ pathway. Under normal conditions, an adequate supply of this aminoacyl-tRNA is available to both pathways. However, under certain circumstances, Glu-tRNA^Glu can become scarce, resulting in competition between the two pathways for this aminoacyl-tRNA. In Acidithiobacillus ferrooxidans, glutamyl-tRNA synthetase 1 (GluRS1) is the main enzyme that synthesizes Glu-tRNA^Glu. Previous studies have shown that GluRS1 is inactivated in vitro by hydrogen peroxide (H₂O₂). This raises the question as to whether H₂O₂ negatively affects in vivo GluRS1 activity in A. ferrooxidans and whether Glu-tRNA^Glu distribution between the heme and protein biosynthesis processes may be affected by these conditions. To address this issue, we measured GluRS1 activity. We determined that GluRS1 is inactivated when cells are exposed to H₂O₂, with a concomitant reduction in intracellular heme level. The effects of H₂O₂ on the activity of purified glutamyl-tRNA reductase (GluTR), the key enzyme for heme biosynthesis, and on the elongation factor Tu (EF-Tu) were also measured. While exposing purified GluTR, the first enzyme of heme biosynthesis, to H₂O₂ resulted in its inactivation, the binding of glutamyl-tRNA to EF-Tu was not affected. Taken together, these data suggest that in A. ferrooxidans, the flow of glutamyl-tRNA is diverted from heme biosynthesis towards protein synthesis under oxidative stress conditions.     

Preparation of hydrophobic electrocatalyst layer and inorganic porous electrolyte layer for water absorbing porous electrolyte electrolysis cell

A water-absorbing porous electrolyte electrolysis cell is presented consisting of a hydrophobic gas diffusion layer (GDL), a controlled-hydrophobicity electrocatalyst layer, and a hydrophilic porous electrolyte layer. The specific character of this cell is that high-pressure water is injected directly into the porous electrolyte layer and is resisted by the electrocatalyst layer and GDL, which have strong water support force. In this study, the preparation method of the electrocatalyst layer and the porous inorganic electrolyte layer, and the evaluation of water electrolysis using the prepared layers were investigated. The optimized conditions and preparation methods of each layer of the MEA (i.e. the GDL, electrocatalyst layer, electrolyte layer) were determined. The assembly method and conditions of these three layers were also determined for fabricating MEAs for water electrolysis. The evaluation of water electrolysis tests using this MEA showed that the hydrogen evolution rate obeyed Faraday's Law in the low current density region (<10 mA cm^?2).