PEG‐Citrate dendrimer second generation: is this a good carrier for imaging agents In Vitro and In Vivo ?

While cancer is the leading cause of human''s deaths worldwide, finding an imaging agent which can detect cancer tumours is needed for cancer diagnosis. In the present study, PEG‐citrate dendrimer‐G₂ was used as a nano‐carrier of FITC dye and Iohexol to help passive targeting and uptake of both imaging agents in cancer cells/tumour in vitro and in vivo. Dendrimer was synthesisedand the product characterised using LC‐MS, FT‐IR, DLS, ELS, AFM, and ¹ HNMR. After FITC loading into dendrimer, MTT was performed to determine the cytotoxicity of formulation on HEK‐293 and MCF‐7 cells. In vitro imaging using dendrimer‐FITC was done via fluorescent microscope thereafter. Moreover, CT imaging using Iohexol was employed to show the targeting nature and ability of the complex to use as imaging agent in vivo. Data yielded in this study corroborate the notion that the promised dendrimer was synthesised properly and had no toxicity along with FITC on normal cell. Furthermore, CT and fluorescent images showed the targeting nature and imaging ability of Iohexol/FITC loaded dendrimer in vitro and in vivo. Overall, results showed promising characteristics of the novel complexes using dendrimer‐G₂ both in vitro and in vivo.Inspec keywords: drug delivery systems, cellular biophysics, molecular biophysics, fluorescence, cancer, tumours, drugs, nanomedicine, biomedical materials, dyes, toxicologyOther keywords: imaging agent, cancer tumours, cancer diagnosis, PEG‐citrate dendrimer‐G, FITC dye, cancer cells, FITC loading, vitro imaging, dendrimer‐FITC, CT imaging, targeting nature, promised dendrimer, fluorescent images, imaging ability, Iohexol/FITC     

An evolutionary algorithm approach to generate distinct sets of non-dominated solutions for wicked problems

Many engineering design problems must optimize multiple objectives. While many objectives are explicit and can be mathematically modeled, some goals are subjective and cannot be included in a mathematical model of the optimization problem. A set of alternative non-dominated fronts that represent multiple optima for problem solution can be identified to provide insight about the decision space and to provide options and alternatives for decision-making. This paper presents a new algorithm, the Multi-objective Niching Co-evolutionary Algorithm (MNCA) that identifies distinct sets of non-dominated solutions which are maximally different in their decision vectors and are located in the same non-inferior regions of a Pareto front. MNCA is demonstrated to identify a set of non-dominated fronts with maximum difference in decision vectors for a set of real-valued problems.     

Design and synthesis of zero–zero‐birefringence polymers using N‐methylmaleimide

Zero–zero‐birefringence polymers which exhibit no orientational birefringence and no photoelastic birefringence may be suitable candidates for the components of optical devices. To develop zero–zero‐birefringence polymers, a novel copolymerization system is required. We investigated two types of birefringence of poly(N‐methylmaleimide) (PMeMI) and showed that PMeMI exhibits positive orientational and photoelastic birefringence. On the basis of the results, we calculated the optimal composition for compensating both types of birefringence by solving three equations which describe the relationship between birefringence properties and weight fraction of monomers. When the copolymer compositions were MMA/BzMA/MeMI = 86/8/6 and 88/8/4 (wt %), zero–zero‐birefringence polymers were obtained. By using MeMI as a comonomer, these zero–zero‐birefringence polymers have a much higher glass transition temperature (T_g) than those of previous researches. Also, this polymer film has high transparency comparable with that of PMMA film. Therefore, we conclude that we successfully prepared zero–zero‐birefringence polymers using N‐substituted maleimide and that N‐substituted maleimide is a promising material for zero–zero‐birefringence polymers for optical devices. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40423.     

A note on “Fuzzy differential equations and the extension principle”

In this note, we show by an example that the main result in a paper by Bassanezi et al. [M.T. Mizukoshi, L.C. Barros, Y. Chalco-Cano, H. Román-Flores, R.C. Bassanezi, Fuzzy differential equations and the extension principle, Information Sciences 177 (2007) 3627-3635], is incorrect.     

Investigation of rheological,mechanical, and thermal properties of nanocomposites based on nitrile rubber-phenolic resin reinforced with nanographene

In this study, nanocomposites of acrylonitrile butadiene rubber (NBR)/phenolic resin/graphene nanoparticles (GNPs) were prepared using a two-roll mill. According to the results, the addition of GNPs increased the scorch time, vulcanization time, and viscosity of the blends. By adding phenolic resin and in the presence of a higher percentage of acrylonitrile, the modulus and tensile strength increased and the elongation at break decreased. The mechanical properties of the nanocomposites improved with increasing the amount of nanoparticles. The addition of 1.5 phr GNP to the blends containing NBR with 33% and 45% acrylonitrile increased the tensile modulus by 56% and 49%, respectively. The tensile properties of the nanocomposites were also investigated at 50, 25, and 75°C. It was observed that with increasing the amount of nanoparticles, the deterioration of the mechanical properties at elevated temperatures was reduced. Also, thermal stability increased with increasing the amount of nanoparticles in all the samples.     

An econometrics view of worldwide fossil fuel consumption and the role of US

Crude oil, coal and gas, known as fossil fuels, play a crucial role in the global economy. This paper proposes new econometrics modelling to demonstrate the trend of fossil fuels consumption. The main variables affecting consumption trends are: world reserves, the price of fossil fuels, US production and US net imports. All variables have been analysed individually for more than half a century. The research found that while the consumption of fossil fuels worldwide has increased trends in the US production and net imports have been dependent on the type of fossil fuels. Most of the US coal and gas production has been for domestic use, which is why it does not have a strong influence on worldwide fossil fuel prices. Moreover, the reserves of fossil fuels have not shown any diminution during the last couple of decades and predictions that they were about to run out are not substantiated. The nominal and real price of fossil fuels was found to change depending on the type. Finally, estimates of three econometric models for the consumption of fossil fuels from 1949 to 2006 are presented which identify the effects of significant variables.     

A new Levinson–Durbin based 2-D AR model parameter estimation method

This paper presents a new method for estimating the parameters of quarterplane two dimensional (2-D) autoregressive model based on the Levinson–Durbin algorithm. To achieve this aim, one-dimensional formulations related to Levinson–Durbin algorithm are extended to 2-D case. Online parameter estimation, capability of parameters variation detection, estimation improvement by using new data and less computational requirement are the significant advantages of the proposed method. Because of not involving complex and time consuming matrix computations, the presented method is computationally efficient. Numerical simulations are presented to show the efficiency of the proposed approach.     

Fast synthesis of MgAl2O4‒W and MgAl2O4‒W‒W2B composite powders by self-propagating high-temperature synthesis reactions

MgAl₂O₄?W and MgAl₂O₄?W?W₂B composite powders were obtained rapidly in a single step by self-propagating high-temperature synthesis of WO₃?Mg?xAl₂O₃ and WO₃?B₂O₃?Mg?yAl₂O₃ systems. The addition of various Al₂O₃ contents (x and y-values) to the starting materials was considered as the main synthesis parameter. Thermodynamic calculations revealed that the adiabatic temperature of both systems was decreased with increasing Al₂O₃ content. The XRD results indicated that after acid leaching of the WO₃?Mg?xAl₂O₃ combustion products, W and MgAl₂O₄ were formed as the main phases and WO₂, MgWO₄ and Al₂O₃ as the minor constituents in the final composite. On the other hand, MgAl₂O₄?W composites were synthesized in the WO₃?B₂O₃?Mg?yAl₂O₃ system at y<1.4 mol. By increasing the y-value to 2.1 mol, W₂B was formed as a new product leading to production of MgAl₂O₄?W?W₂B composite. The formation of spinel was confirmed by the Fourier transformed infrared spectroscopy analysis. Microstructure observations represented the uniform distribution of MgAl₂O₄ blocks within the fine spherical W particles. The melting of Al₂O₃ was found as a vital step for rapid synthesis of MgAl₂O₃ by the SHS route. Finally, the possible formation mechanism of MgAl₂O₄ during the combustion synthesis was proposed.