Síntesis de una estructura nanoporosa de metal orgánico para el suministro controlado de azatioprina

New drug delivery systems are highly efficient in diseases diagnosis and treatment and also controlled release of drugs. The use of this technology has given rise to the invention of new porous nanoparticles which are called metal organic frameworks (MOFs). In the present research, a kind of MOFs with formula Cu3(BTC)2 (HKUST-1, BTC ¼ benzene-1,3,5-tricarboxylate) with Fe3O4 magnetic nanoparticles (MNPs) as a core have been able to create three-dimensional magnetic porous structures. This magnetic and porous structure and the pores capability in being controlled have made these frameworks to be used as one of the best carriers in drug delivery. This system could magnetically be directed to the considered point inside body if it contains a drug that has side effects and may harm other body organs. Azathioprine is used in rheumatoid arthritis, granulomatosis with polyangiitis, Crohn's disease, ulcerative colitis, systemic lupus erythematosus, and in kidney transplants to prevent rejection. However, in the present work we consider the drug injection for kidney transplants to prevent rejection.Los nuevos sistemas de administración de fármacos son altamente eficientes en el diagnóstico y tratamiento de enfermedades y también en la liberación controlada de fármacos. El uso de esta tecnología ha dado lugar a la invención de nuevas nanopartículas porosas que se denominan estructuras organometálicas (MOF). En la presente investigación, una especie de MOF con fórmula Cu3 (BTC) 2 (HKUST-1, BTC ¼ benceno-1,3,5-tricarboxilato) con nanopartículas magnéticas (MNP) de Fe3O4 como núcleo han podido crear tres- estructuras porosas magnéticas dimensionales. Esta estructura magnética y porosa y la capacidad de control de los poros han hecho que estas estructuras se utilicen como uno de los mejores vehículos en la administración de fármacos. Este sistema podría dirigirse magnéticamente al punto considerado dentro del cuerpo si contiene un medicamento que tiene efectos secundarios y puede dañar otros órganos del cuerpo. La azatioprina se usa en artritis reumatoide, granulomatosis con poliangeítis, enfermedad de Crohn, colitis ulcerosa, lupus eritematoso sistémico y en trasplantes de riñón para prevenir el rechazo. Sin embargo, en el presente trabajo consideramos la inyección de fármacos para trasplantes de riñón para prevenir el rechazo

Effect of Drying Conditions on the Catalytic Performance, Structure, and Reaction Rates over the Fe-Co-Mn/MgO Catalyst for Production of Light Olefins

The MgO-supported Fe-Co-Mn catalysts, prepared using co-precipitation procedure, were tested for production of light olefins via CO hydrogenation reaction. The effect of a range of drying conditions including drying temperature and drying time on the structure and catalytic performance of Fe-Co-Mn/MgO catalyst for Fischer-Tropsch synthesis was investigated in a fixed bed micro-reactor under the same operational conditions of T = 350 °C, P = 1 bar, H2/CO = 2/1, and GHSV = 4500 h-1. It was found that the catalyst dried at 120 °C for 16 h has shown the best catalytic performance for CO hydrogenation. Furthermore, the effect of drying conditions on different surface reaction rates was also investigated and it was found that the precursors drying conditions influenced the rates of different surface reactions. Characterization of catalyst precursors and calcined samples (fresh and used) was carried out using powder X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Brunauer-Emmett-Teller (BET) measurements, Temperature Programmed Reduction (TPR), Thermal Gravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC). Characterization results showed that different investigated variables (drying conditions) influenced the structure, morphology and catalytic performance of the ternary catalysts.

Fabrication of chelating diethylenetriaminated pan micro and nano fibers for heavy metal removal

In this study, commercial acrylic fibers were modified with diethylenetriamine to prepare metal chelating fibers. The effects of process parameters on the efficiency of the reaction were investigated. FTIR spectroscopy and TGA analysis were used to confirm the chemical changes made to the fibers during the reaction. The ability of the modified fibers for removal of Pb (II), Cu (II) and Ce (IV) ions from aqueous media was determined. The modified fibers showed a slight decrease in mechanical properties compared to raw ones. Furthermore, the acrylic micro fibers were electrospun to nanofibers and the ability of modified nanofibers for the adsorption of the metal ions was studied

COMPARISON OF RESISTANCE AND BIODEGRADABILITY PROPERTIES OF WOOD-PLASTIC COMPOSITES FROM WOOD FLOUR/ PHB / HDPE / STARCH

In this study, mechanical and biodegradability properties of wood plastic composite were investigated. Beech (fagus orientalis) flour 40 wt% was used as a reinforcing base material, maleic anhydride as a coupling agents and nano clay to improve the properties were added. The polymer studied was polyhydroxybutyrate (PHB) and the other polymer was high-density polyethylene (HDPE) .Three groups of composites were produced, in two groups each of the polymers alone and in the third group a combination of two types of polymers was used as a matrix. Starch 8 wt% and 12wt% was used as a copolymer. The specimens were mixed using a twin-screw extruder and made with an injection molding machine and subjected to mechanical tests: tensile strength and module, bending strength and module, impact resistance tests and biodegradability tests. In mechanical properties, it was observed that wood plastic composite with PHB base material has lower resistance properties than composites containing HDPE. With the addition of starch, all resistance properties were significantly reduced compared to the control sample without starch in all three groups of composite samples. Starch could not play the role of copolymer well in any of the groups. The third group of samples presented better results in terms of resistance properties than the first group. Modulus and resistances increased compared to the first group. In the biodegradability test, the samples were buried at a height of 25 cm for three months. Weight loss was due to the destruction of wood flour, starch and natural polymers by soil microorganisms. The weight loss trend of the samples was increasing until the end of the second month and then decreasing

Pressure responsive nanogel base on Alginate‐Cyclodextrin with enhanced apoptosis mechanism for colon cancer delivery

5‐Fluorouracil (5‐Fu) commonly use in the treatment of different kinds of cancer, but limited cellular uptake and death is still a problem. Herein, we report a simple process for the synthesis of pressure‐sensitive nanogels that indicate to be appropriate in the delivery of 5‐Fu. The hydrogels (Al‐CD) prepare by crosslinking of alginate (Al) with modified beta Cyclodextrin (β‐CD) as Crosslinker. Next, nanoparticles obtaine by an emulsification method. 5‐Fu as model drug loades into the Al‐CD nanogels easily by mixing it in aqueous solution with the nanoparticles. The results revealed that the Al‐CD nanogels are cytocompatible. They have also a noticeable drug encapsulation (82.1 ±5.7%) while they can release (in vitro controlled) 5‐Fu in conditions that imitate the intravascular pressure conditions. These nanogels can rapidly be taken up by HT‐29 cells (a colon cell line). In addition, a higher 5‐Fu intracellular accumulation and a significant cell death extension by apoptosis mechanism is notice when compare with free 5‐Fu. Accordingly, the developed nanogels can be employe as an excellent candidate to overcome the inefficiency of 5‐Fu in anticancer treatments and possibly can employe for further evaluation as a chemotherapical agent in applications beyond cancer. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 349–359, 2018.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143710/1/jbma36242.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143710/2/jbma36242_am.pd

The Impacts of Nanoclay on Sandy Soil Stability and Atmospheric Dust Control

Wind erosion and dust storms are main issues in arid and semi-arid regions. Application of soil stabilizer on unstable land might be an effective and sustainable strategy in arid and semi-arid countries to minimized harmful effects on environment and human health. The aim of this study was to assess the effect of using nanoclay for increasing soil stability, as a result of increasing in size of soil aggregation, and improving soil water holding capacity, as well as improving soil structure in sandy soil. An experiment was conducted with two treatments (0 and 3000 mg/l nanoclay were uniformly spread on the soil surface) in four replications on sandy soil, in Khara desert, nearly 100 km east of Isfahan, Iran. The annual rainfall is about 68/55 mm, mean annual ET0 is 2800 mm/year, and the elevation is 1450 m above sea level. Amount of soil erosion was measured with different wind velocity (31.0, 55.2 and 67.3 km h−1). An aggregation size and water retention of collected soil samples were measured by sieves and pressure plate, respectively. The results showed that the amount of soil erosion in nanoclay-treated soils was significantly different (P>0.05) in comparison with water-treated (control) soils. The volumetric water content at 100 KPa increased in nanoclay-treated soils compared to control treatment. Results also showed that the proportion of 0.25-2 mm aggregate (macroaggregate) significantly increased in nanoclay-treated soils. Based on aforementioned results, it can be concluded that application of nanoclay on soil surface is able to fix the sand and it has ability to cement the particles to each other, increase aggregation and reduce wind erosion. The results suggested that more attention should be directed towards using nanoclay on soil surface of unstable soil areas. That coild be an option for control of the atmospheric dust

The Impacts of Nanoclay on Sandy Soil Stability and Atmospheric Dust Control

Wind erosion and dust storms are main issues in arid and semi-arid regions. Application of soil stabilizer on unstable land might be an effective and sustainable strategy in arid and semi-arid countries to minimized harmful effects on environment and human health. The aim of this study was to assess the effect of using nanoclay for increasing soil stability, as a result of increasing in size of soil aggregation, and improving soil water holding capacity, as well as improving soil structure in sandy soil. An experiment was conducted with two treatments (0 and 3000 mg/l nanoclay were uniformly spread on the soil surface) in four replications on sandy soil, in Khara desert, nearly 100 km east of Isfahan, Iran. The annual rainfall is about 68/55 mm, mean annual ET0 is 2800 mm/year, and the elevation is 1450 m above sea level. Amount of soil erosion was measured with different wind velocity (31.0, 55.2 and 67.3 km h−1). An aggregation size and water retention of collected soil samples were measured by sieves and pressure plate, respectively. The results showed that the amount of soil erosion in nanoclay-treated soils was significantly different (P>0.05) in comparison with water-treated (control) soils. The volumetric water content at 100 KPa increased in nanoclay-treated soils compared to control treatment. Results also showed that the proportion of 0.25-2 mm aggregate (macroaggregate) significantly increased in nanoclay-treated soils. Based on aforementioned results, it can be concluded that application of nanoclay on soil surface is able to fix the sand and it has ability to cement the particles to each other, increase aggregation and reduce wind erosion. The results suggested that more attention should be directed towards using nanoclay on soil surface of unstable soil areas. That coild be an option for control of the atmospheric dust

Effects Of Nano-Clay Particles And Oxidized Polypropylene Polymers On Improvement Of The Thermal Properties Of Wood Plastic Composite

In this study, the effects of oxidized polypropylene, as a compatibilizer, and Nano-clay particles in improving the thermal properties of wood plastic composites are investigated. For this purpose, polypropylene polymer was oxidized in the vicinity of the air oxygen for 2 hours. Then, in order to produce the samples, Nano-clay particles at three levels (0%, 2% and 4%) were mixed with wood fibers, polypropylene polymer and the compatibilizer. Finally, the samples with thickness of 2mm and dimensions of 15×15cm were made by using hot press. For more precise investigation, the morphology of wood plastic composites was studied by using X-rays diffraction and electronic microscope images. Thermal properties of the composites were evaluated through thermal and differential analyses. The results of the thermal tests demonstrated that the addition of oxidized polypropylene and Nano-clay particles significantly improve the thermal properties of wood plastic composites. Furthermore, increment of Nano-clay particles content additionally improves thermal stability of the composites and also reduces the released heat amount during the thermal degradation. In addition, TEM images showed that the dispersion of Nano-clay particles in the composite has an intercalation structure. This subject also verified by the X-rays diffraction and it is an evidence of better thermal stability of the achieved wood plastic composites

An Investigation on Polymerization of Ethylene by Ziegler-Natta Catalyst in the Presence of a Promoter: Polymerization Behavior and Polymer Microstructure

The effect of a halocarbon (ethyl chloride) as a promoter on a Ziegler-Natta catalyst composed of‌ T‌iCl4 (catalyst), AlEt3 (activator) and Mg(OEt)2 (support) in the polymerization of ethylene have been investigated. In addition, the impact of this compound on the structural and thermal properties of the produced polyethylene has been studied. The catalyst activity and polymerization rate increased almost up to twice when a suitable molar ratio of ethyl chloride to triethylaluminum (TEA) was used. There was no change in the type of the profile of the polymerization rate during the polymerization time. A reduction in the polymer molecular weight was observed in the presence of the promoter and hydrogen. In addition, the MWD curve shifted toward lower values in the presence of ethyl chloride. Furthermore, a numerical method was used to obtain the most probable chain-length distribution, number   average molecular weight and weight fraction corresponding to each site type in the presence and absence of the promoter. Since, the catalyst had an irregular shape, the produced polymer also showed a similar morphology. In addition, the promoter used in the polymerization did not have any effect on the produced polymer morphology. The DSC results indicated that the presence of the promoter in the polymerization led to a decrease in the melting point of the produced polymer; whereas, there were no remarkable changes in the crystallization temperature of the polymers. Copyright © 2018 BCREC Group. All rights reserved Received: 2nd October 2017; Revised: 5th April 2018; Accepted: 26th April 2018 How to Cite: Gholami, Y., Abdouss, M., Abedi, S., Azadi, F., Baniani, P., Arsalanfar, M. (2018). An Investigation on Polymerization of Ethylene by Ziegler-Natta Catalyst in the Presence of a Promoter: Polymerization Behavior and Polymer Microstructure. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (3): 412-419 (doi:10.9767/bcrec.13.3.1574.412-419) Permalink/DOI: https://doi.org/10.9767/bcrec.13.3.1574.412-41

Essential role of structure, architecture, and intermolecular interactions of asphaltene molecules on properties (self-association and surface activity)

One of the important challenges of the oil industry is the formation of asphaltene deposits and emulsions, which cause many operational and economic problems. Asphaltenes are heavy and polar fractions of petroleum with a mixture of diverse molecules. Their structural complexity makes the understanding of their properties puzzling. The purpose of this review is to understand the self-association and surface activity properties of asphaltenes. There are some popular models for the mechanism of asphaltene aggregation; each alone is not complete and without defects. Experimental studies and molecular dynamics demonstrate that the mechanism of aggregation is influenced by asphaltene’ structure, architecture, and intermolecular forces. Factors such as oil composition, temperature, and pressure affect its intensity. In this article, these issues and their impact on the self-assembly of asphaltenes and ways to prevent it, especially chemical inhibitors, have been discussed in detail