Rapid and highly efficient synthesis of thioureas in biocompatible basic choline hydroxide

A straightforward and convenient synthesis of symmetrical thiourea derivatives by the reaction of primary amines and carbon disulfide in biocompatible basic choline hydroxide is presented. A variety of biologically important thiourea derivatives can be obtained in good to excellent yields without a tedious work-up under mild reaction conditions. A series of primary aliphatic and aromatic amines with different substituted functional groups have been converted to thiourea derivatives under milder reaction conditions and short reaction times.     

Automatic fire detection based on soft computing techniques: review from 2000 to 2010

Automatic fire detection system is a system that is capable of assessing environmental factors and their effects on the environment as well as predicting the occurrence of fire in the early stages and even before the outbreak. There are two perspectives in fire detection: fire detection in forests or jungles and fire detection in occupied or residential areas. Automatic fire detection has attracted increased attention due to its importance in decreasing fire damage. There are many studies that have considered appropriate techniques for early fire detection. In recent years researches have been studying technical developments in this field aimed at exploiting wireless communications networks, detection systems and fire prediction systems design. In this paper the automatic fire detection researches using intelligent techniques from 2000 to 2010 is reviewed. We could classify researches to four categories: fire detectors, reduce false alarms systems, fire data analysis and fire predictors. We also classify the intelligent techniques outlined in the researches for each category.     

A PSO-based model to increase the accuracy of software development effort estimation

Development effort is one of the most important metrics that must be estimated in order to design the plan of a project. The uncertainty and complexity of software projects make the process of effort estimation difficult and ambiguous. Analogy-based estimation (ABE) is the most common method in this area because it is quite straightforward and practical, relying on comparison between new projects and completed projects to estimate the development effort. Despite many advantages, ABE is unable to produce accurate estimates when the importance level of project features is not the same or the relationship among features is difficult to determine. In such situations, efficient feature weighting can be a solution to improve the performance of ABE. This paper proposes a hybrid estimation model based on a combination of a particle swarm optimization (PSO) algorithm and ABE to increase the accuracy of software development effort estimation. This combination leads to accurate identification of projects that are similar, based on optimizing the performance of the similarity function in ABE. A framework is presented in which the appropriate weights are allocated to project features so that the most accurate estimates are achieved. The suggested model is flexible enough to be used in different datasets including categorical and non-categorical project features. Three real data sets are employed to evaluate the proposed model, and the results are compared with other estimation models. The promising results show that a combination of PSO and ABE could significantly improve the performance of existing estimation models.     

Sustained drug release using supramolecular hydrogels composed of cyclodextrin inclusion complexes with PCL/PEG multiple block copolymers

Methadone hydrochloride is a narcotic drug used to relieve chronic pain and control withdrawal symptoms in people undergoing detoxification for opiate addiction, but poses some limits. To reduce the limits and increase the drug’s effectiveness, supramolecular hydrogels composed of α-CD (α-cyclodextrin) and PCL/PEG (polycaprolactone/polyethylene glycol) copolymers, which gained attention due to their advantages, were chosen in this study as controlled-release formulations. PCL/PEG/PCL and PCL/PEG copolymers were synthesized by a microwave-assisted method and then supramolecular hydrogels were prepared by mixing the solutions of copolymers/drug and α-CD to make a methadone hydrochloride sustained-release system. Effects of the drug, copolymer, and α-CD concentrations and copolymer structure on gelation time were also investigated. The systems had rheological properties that depended on copolymer construction and component concentrations. The microwave-assisted method provides an accelerated synthesis of the copolymers with yield of 57 % and low level of impurities. The supramolecular hydrogels demonstrated shear thinning and thixotropic behavior and regained their networks quickly after passing through a fine needle. Due to the porous construction of supramolecular hydrogels, they swell in the presence of fluids and absorb large quantities of water, thereby making the system comprehensively biocompatible. In this study, supramolecular hydrogels composed of α-CD with tri- and di-block copolymers were investigated and found to have rheological properties that depended on copolymer construction and component concentrations. Changing one parameter alone like copolymer or α-CD concentration or the length of blocks could not significantly affect on the drug release, but combination of these factors was efficient. Results of the present study indicated that supramolecular hydrogels composed of α-CD and PCL/PEG copolymers are appropriate drug delivery systems that can release methadone hydrochloride in a sustained manner.     

Photoluminescence study of SBA-15@ZnO/Au nanocomposite for potential use in Staphylococcus aureus detection

Journal of Porous Materials - Staphylococcus aureus is most common causes of hospital-acquired infections and food-associated disease. In the last years, sensing platform based on fluorescence-...     

Super Magnetic Niosomal Nanocarrier as a New Approach for Treatment of Breast Cancer: A Case Study on SK-BR-3 and MDA-MB-231 Cell Lines

In the present study, a magnetic niosomal nanocarrier for co-delivery of curcumin and letrozole into breast cancer cells has been designed. The magnetic NiCoFe₂O₄ core was coated by a thin layer of silica, followed by a niosomal structure, allowing us to load letrozole and curcumin into the silica layer and niosomal layer, respectively, and investigate their synergic effects on breast cancer cells. Furthermore, the nanocarriers demonstrated a pH-dependent release due to the niosomal structure at their outer layer, which is a promising behavior for cancer treatment. Additionally, cellular assays revealed that the nanocarriers had low cellular uptake in the case of non-tumorigenic cells (i.e., MCF-10A) and related high viability but high cellular uptake in cancer cell lines (i.e., MDA-MB-231 and SK-BR-3) and related low viability, which is evidenced in their high cytotoxicity against different breast cancer cell lines. The cytotoxicity of the letrozole/curcumin co-loaded nanocarrier is higher than that of the aqueous solutions of both drugs, indicating their enhanced cellular uptake in their encapsulated states. In particular, NiCoFe₂O₄@L-Silica-L@C-Niosome showed the highest cytotoxicity effects on MDA-MB-231 and SK-BR-3 breast cancer cells. The observed cytotoxicity was due to regulation of the expression levels of the studied genes in breast cancer cells, where downregulation was observed for the Bcl-2, MMP 2, MMP 9, cyclin D, and cyclin E genes while upregulation of the expression of the Bax, caspase-3, and caspase-9 genes was observed. The flow cytometry results also revealed that NiCoFe₂O₄@L-Silica-L@C-Niosome enhanced the apoptosis rate in both MDA-MB-231 and SK-BR-3 cells compared to the control samples. The findings of our research show the potential of designing magnetic niosomal formulations for simultaneous targeted delivery of both hydrophobic and hydrophilic drugs into cancer cells in order to enhance their synergic chemotherapeutic effects. These results could open new avenues into the future of nanomedicine and the development of theranostic agents.     

Extracellular Vesicles: Interplay with the Extracellular Matrix and Modulated Cell Responses

The discovery that cells secrete extracellular vesicles (EVs), which carry a variety of regulatory proteins, nucleic acids, and lipids, has shed light on the sophisticated manner by which cells can communicate and accordingly function. The bioactivity of EVs is not only defined by their internal content, but also through their surface associated molecules, and the linked downstream signaling effects they elicit in target cells. The extracellular matrix (ECM) contains signaling and structural molecules that are central to tissue maintenance and repair. Recently, a subset of EVs residing within the extracellular matrix has been identified. Although some roles have been proposed for matrix-bound vesicles, their role as signaling molecules within the ECM is yet to be explored. Given the close association of EVs and the ECM, it is not surprising that EVs partly mediate repair and regeneration by modulating matrix deposition and degradation through their cellular targets. This review addresses unique EV features that allow them to interact with and navigate through the ECM, describes how their release and content is influenced by the ECM, and emphasizes the emerging role of stem-cell derived EVs in tissue repair and regeneration through their matrix-modulating properties.     

Production and characterization of nanocomposites based on poly(amide-imide) containing 4,4′-methylenebis(3-chloro-2,6-diethylaniline) using nano-TiO2 surface-coupled by 3-aminopropyltriethoxysilane

In this work, the poly(amide-imide) (PAI) was synthesized from the polymerization reaction of 4,4′-methylenebis(3-chloro-2,6-diethyl trimellitimidobenzene) as a diacid with 4,4′-methylenebis(3-chloro-2,6-diethylaniline) under green condition using molten tetra-n-butylammonium bromide and triphenylphosphite. Ultrasonic technique was used for preparation of PAI/TiO₂ nanocomposites (PAI/TiO₂ NCs). For the improvement of TiO₂ nanoparticles (NPs) dispersion and enhancing interactions between NPs and polymeric matrix the surface of TiO₂ was successfully modified by silane coupling agent (3-aminopropyltriethoxysilane). The resulting NCs were characterized by FT-IR, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The TGA of the obtained NCs proves the enhancement in the thermal stability with an increase in the percentage of titania NPs. TEM and FE-SEM images showed that the NPs were uniformly dispersed in the polymer matrix. The shielding effect of nano TiO₂ under UV radiation was examined by UV–vis.     

Hydrothermal synthesis of pure AlPO4-5 without fluoride medium: synthesis, characterization and application as a support

Hydrothermal synthesis of pure AlPO₄-5 crystals using various reaction gels is reported. The influence of synthesis conditions on the purity of the AlPO₄-5 has been studied by changing Al sources and factors affecting the pH of the starting gel. It was observed that the additive acid to adjust the gel pH value has strongly influenced both the crystallinity and purity of the resulting AlPO₄-5 crystals. The crystals were characterized by XRD, FT-IR, TGA, BET, SEM and TPD techniques. The resulting microporous AlPO₄-5 was used as an efficient support for a functional polymer to produce an efficient heterogeneous basic nanocomposite catalyst. The catalytic activity of this novel nanocomposite was tested for Knoevenagel reaction under solvent-free conditions at room temperature. The catalyst showed a considerable degree of reusability besides very good activity.     

Effects of formulation properties on sol–gel behavior of chitosan/glycerolphosphate hydrogel

Chitosan solution containing glycerolphosphate disodium salt (Gp) is an injectable thermosensitive in situ gel-forming system which undergoes sol–gel transition under certain physiological pH and temperature conditions. When a drug-incorporated chitosan/Gp solution is injected into the body, it forms a three-dimensional gel at 37 °C, which allows the drug to be released in a sustained manner. This hydrogel can be used as a drug delivery system for prolonged release of peptides and glycopeptides. The objective of this work was to investigate the effect of different excipients on the sol–gel behavior of this thermosensitive hydrogel. Chitosan polymeric solutions (2 % w/v) containing Gp and different excipients, such as hydroxypropyl methyl cellulose (HPMC), polyethylene glycol (PEG) with two different molecular weights (PEG200 and PEG1000), and poloxamer (F127) in various concentrations, were prepared, and the pH, sol–gel transition time, and syringeability of the final solutions were evaluated. The obtained results point to HPMC as the best additive for chitosan/Gp solutions in developing an in situ gel-forming drug delivery system with optimum gelling time. A significant decrease was noted in the sol-to-gel transition time (from 90 to 60 s) when HPMC was added to the system. This may have been due to the HPMC structure which acted as a viscosity-enhancing and gel-promoting agent. The in vitro release of vancomycin hydrochloride from chitosan/Gp/HPMC hydrogel was also studied. Vancomycin release studies showed a sustained release profile for over 20 days. It can be concluded that combining chitosan/Gp and HPMC is a promising strategy for preparing a thermally reversible in situ gel-forming delivery system with an optimized gelation time.