Journal of Sciences, Islamic Republic of Iran
Volume:31 Issue: 4, Autumn 2020

In the present study for the first time, a novel polyacrylonitrile-silver nanocomposite nanofiber was synthesized by electrospinning for adsorbing sulfur compounds in natural gas condensate. The synthesized material was characterized by SEM, EDAX, and XRD. The presence of C, N, O, and Ag proved that the composite was synthesized successfully. In order to achieve the best adsorption conditions, the effect of contact time, adsorbent dosage and initial sulfur compound concentration was examined. Under optimal values, efficiency of greater than 90% was found. In addition, different isotherms and kinetics models were tested to describe the sorption process. It was found that Freundlich (0.9900) was superior to Langmuir (0.9688), Temkin (0.9648) and Dubinin-Radushkevich (0.8273) models, revealing that sulfur compounds tend to for, multilayers on the heterogeneous surface of polyacrylonitrile-silver nanocomposite nanofiber. The energy value of the adsorption was 23.57 kJ/mol, indicating chemisorption reactions. Based on kinetics studies, the desulfurization by nanofibers followed Pseudo-second-order and Elovich kinetics. Finally, the desulfurization function of nanocomposite was studied and validated using adsorbent columns. The obtained results demonstrate polyacrylonitrile-silver nanocomposite nanofiber as a promising material in the field of desulfurization.

Alzheimer's disease is an irreversible chronic neurodegenerative disease which is the most common cause of dementia among older adults. According to amyloid hypothesis, cholin neurotransmitters have important roles in CNS memory function, therefore cholinesterase inhibitors can improve the Alzheimer's symptoms. In recent decades, marine creatures have become interested for their huge medicinal effects and potential of pharmaceutical preparations. Marine classifications contain pharmacologically active compounds with capibilities for improvement of cognitive disorders. This article provides a comprehensive overview of cholinesterase inhibitors from marines in 4 categories contain seaweeds, marine sponges, coelenterates and other invertebrates over the 47 years from 1970 to 2017 which resulted into important bioactive extracts and isolated compounds which representing a diverse range of structural classes such as pyrrole derivatives, sesquiterpene acetates, tetrazacyclopentazulene, bromotyrosine derivatives, plastoquinones, farnesylacetones and poly-alkylpyridinium polymers (Poly-APS). For each structural group, the important compounds with cholinesterase inhibition activities were introduced. The result showed marins can be considered as important sources to discover new cholinesterase inhibitiors.

Bavanat red bed copper deposits (Jolani area) are located in south Sanandaj-Sirjan metamorphic belt and approximately 15 km NW of Bavanat. In terms of lithology, these deposits include purple to red siltstone(PSS) which are also seen among the layers of green sandstone(GS). Copper mineralization such as malachite is observed in the GS unit at the surface. Both PSS and GS units have Jurassic age. The current study, has used Landsat 8 and SPOT 5 images for RS processing. This study indicated that RGB=432 color composite in SPOT 5 image has the best contrast for enhancement and detection of PSS and GS units. Only the Landsat 8 fused image has been able to enhance and detect the GS unit. Also, based on band ratio technique, RGB=(b6/b2), (b5/b3), (b7/b1) color composite for Landsat 8 data, has the best contrast for PSS and GS units. PCA method shows that RGB=PC4, PC2, PC1 for Spot 5 dataand RGB=PC1, PC2, PC3 for Landsat 8 data have the best contrast for enhancement and detection of the Bavanat red bed copper deposits. In this study, different methods of supervised classification such as SAM, SID and SVM were reviewed. Among these methods, SVM technique has the best layout for SPOT 5 image. This important layout as a basic geological map, can be very useful in additional exploration studies on the Bavanat red bed deposits.

Challenges such as advances in technology, demands of the global market, and limited warehouse spaces resort manufacturing industries to subcontracting. Subcontracting has been a considerable alternative in the manufacturing industries and is utilized as a strategic tool to diminish operation costs primarily to address the problem of scarcity when the firm faces a large demand on the commodity it supplies. The present study employed a mathematical model among firms engaging in subcontracting in search of an optimal schedule in the manufacture of the product and distribution of production time involved with an objective of obtaining a maximum profit. The constraints in the mathematical formulation included the total demand, processing capacity, available supply, processing rate, and time. The plausibility and the possible utility of the mathematical model has been explored employing sequential quadratic programming algorithm in the search of the optimal solutions.

The present study aimed to prepare Fe3O4 nanocarriers (NCs) by a thermal treatment method. After the Fe3O4 (Fe) NCs was prepared, zinc oxide and silica nanoparticles were added to it as Photosensitizer. The structure, morphology, and magnetic properties of Fe3O4@ZnO (Fe@Zn) and Fe3O4@SiO2 (Fe@Si) NCs were determined by XRD, FT-IR, FESEM, and VSM. Then, the loading and drug release of Fe, Fe@Zn, and Fe@Si NCs were investigated. The curcumin (CUR) release of Fe@Zn+CUR and Fe@Si+CUR increased from 30% and 26% at pH 7.4 to 53% and 57% at pH 5.5, respectively. The cytotoxicity of Fe@Zn and Fe@Si NCs were determined by MTT assay, hemolysis test, acute toxicity, and lethal dose test. The results showed that Fe@Zn and Fe@Si were appropriate for Photodynamic Therapy (PDT) and in the next step, the effect of Fe@Zn, Fe@Si, Fe@Zn+CUR, and Fe@Si+CUR NCs on MCF-7 cells under  visible light were studied. Finally, the ranking of the destruction of cancerous cells of MCF-7 using NCs under  visible light was: Fe@Zn+CUR>Fe@Zn>Fe@Si+CUR>Fe@Si.