Synthesis,Characterization, and Evaluation of Surface and Thermal Properties and Cytotoxicity of 2-Hydroxy-3-Phenoxypropyl Imidazolium Bola-Type Gemini Amphiphiles

A library of imidazolium-based gemini cationic bola amphiphiles was synthesized using a regioselective ring-opening reaction of glycidyl phenyl ether with imidazole under solvent-free conditions. The corresponding hexafluorophosphate (PF₆⁻) and tetrafluoroborate (BF₄⁻) counterion-containing amphiphiles were also synthesized and characterized using nuclear magnetic resonance (NMR) and mass spectroscopy. The micellar and interfacial parameters like the critical micelle concentration (CMC), surface pressure at the CMC (П_cmc), surface tension at CMC ( γ_cmc ), counterion binding (β), maximum surface excess concentration ( Γ_max ), minimum area per molecule ( A_min ), standard free energy of micellization () and adsorption (), and Kraft temperature were evaluated using surface tension and conductometry methods in aqueous solution as well as in buffer solution. Dynamic light scattering (DLS) was used to determine the size of the micelles formed in the aqueous solution. Cytotoxicity tests were carried out on the C6 glioma cancerous brain cell line using the MTT assay (3-(4, 5-dimethylthiazole-2-yl)-2, 5-diphenyltetrazolium bromide) to evaluate the IC₅₀ value of all the synthesized amphiphiles. Thermal stability of these amphiphiles was also evaluated using a thermal gravimetric analyzer (TGA). Economic way of synthesis, moderate thermal stability, a low value of CMC, and cytotoxicity of these amphiphiles will inspire new research in the field of nanobiotechnology and pharmaceutical industries.     

hSMA-PS: a novel memetic approach for numerical and engineering design challenges

Engineering with Computers - Recent work trend is to hybridize two and more variants in order to recognize better quality of functional and remedies to the global challenges of optimisation. The...     

Synthesis,Characterization and Evaluation of Surface and Thermal Properties of 3‐Cyclohexyloxy‐2‐Hydroxypropyl Pyridinium and Imidazolium Surface‐Active Ionic Liquids

In this work, 1‐halo‐3‐(cyclohexyloxy)propan‐2‐ol ( 3a/3b ) were reacted with N‐methylimidazole ( 4 ) or pyridine ( 5 ) to yield the respective 3‐(3‐(cyclohexyloxy)‐2‐hydroxypropyl)‐1‐methyl‐1H‐imidazol‐3‐ium ( 6a/6b ) or pyridinium ( 7a/7b ) surface‐active ionic liquids (SAIL). The self‐aggregation behavior of these ionic liquids (IL) was evaluated by conductometric and tensiometric methods. The thermal stability and size of the micelles were determined by thermogravimetric analysis and dynamic light scattering studies, respectively. The investigated IL were found to exhibit very low cytotoxicity as evaluated by MTT (3‐(4, 5‐dimethylthiazol‐2‐yl)‐2, 5‐diphenyltetrazolium bromide) assay on the C6 glioma cell line, indicating that the investigated SAIL can be considered for biological applications like drug and gene delivery. The conventional IL 3‐methyl‐1‐octyl imidazolium bromide ( C ₈ mimBr ) was used for comparison in property evaluations.     

Robot-Assisted Needle Steering Using a Control Theoretic Approach

This paper presents a new 2D motion planner for steering flexible needles inside relatively rigid tissue. This approach uses a nonholonomic system approach, which models tissue-needle interaction, and formulates the problem as a Markov Decision Process that is solvable using infinite horizon Dynamic Programming. Unlike conventional numerical solvers such as the value iterator which inherently suffers from the curse of dimensionality for processing large-scale models, partitioned-based solvers show promising numerical performance. Given the locations of the obstacles and the targeted area, the proposed solver provides a descent solution where high spatial or angular resolution is required. As theoretically expected, it is shown how prioritized partitioning increases computational performance compared to the generic value iteration which has been used in an existing steering approach. Starting from any initial condition in the workspace, this method enables the needle to reach its target and avoid collisions with obstacles through selecting the shortest path with the least number of turning points thereby causing less trauma. In this paper, emphasis is given to the control aspects of the problem rather than to biomedical issues. Experimental results using an artificial phantom show that the method is capable of positioning the needle tip at the targeted area with an acceptable level of accuracy.     

Intelligent Physical Layer Secure Relay Selection for Wireless Cooperative Networks with Multiple Eavesdroppers

Wireless Personal Communications - The modern and emerging wireless communication technologies are benefiting from relaying techniques, which is already adopted in long term evolution (LTE) Release...     

Mg Doped Copper Ferrite with Polyaniline Matrix Core–Shell Ternary Nanocomposite for Electromagnetic Interference Shielding

Electromagnetic interference shielding materials based on polyaniline/Mg_0.6Cu_0.4Fe₂O₄ ternary nanocomposites were prepared using in situ chemical oxidation polymerization method. The crystalline, structural and morphology analyses of the synthesized material were studied by X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR) and high resolution transmission electron microscopy (HR-TEM). The nanocomposites were examined by UV–Vis spectroscopy (UV–Vis), four probe resistivity, vibrating sample magnetometer (VSM), thermal gravimetric analysis (TGA) and vector network analyzer (VNA) for the optical, electrical, thermal, magnetic and shielding properties. XRD, FTIR and UV–Vis spectra analyses confirmed the formation of ferrites and polyaniline phases in the composites. The particle sizes of Mg_0.6Cu_0.4Fe₂O₄ are lying in the range of 15–40 nm verified by the HR-TEM. VSM study proved the presence of magnetic nanoparticles in the polyaniline matrix. TGA results revealed that the mixing of ferrites particles in polyaniline has improved its thermal stability. The nanocomposites are showing the significant shielding effectiveness value up to 32.8 dB in the X-band frequency range which makes them potential shielding material for electromagnetic interference shielding applications due to lightweight, good processability and low cost.     

Receptor clustering: activate to accumulate?

Postsynaptic receptor clustering is thought to be of critical importance in central neurotransmission. Recent work suggests that the formation and size of such clusters may depend on synaptic activity, although that dependence appears to vary according to the type of receptor that mediates the postsynaptic response.     

Influence of double application technique on the bonding effectiveness of self‐etch adhesive systems

Aim: To evaluate and compare the effect of double‐application of single‐step self‐etch adhesives using microleakage study and to analyze the dentin–adhesive interfacial micromorphology. Methods: In total, 72 extracted human premolars were divided into three groups for different self‐etch adhesives (G Bond, GC [GB], Optibond, Kerr [OB], and Xeno V Plus, Dentsply [XV]). Class V cavities were prepared. Each group was further divided into two subgroups (n = 10) according to the placement technique of the adhesive, using the single‐application [subgroup (a)] or double‐application method [subgroup (b)]. Resin composite (Z 250, 3M ESPE, St. Paul, MN) was used to restore the cavities and light cured for 40 s. Twenty samples from each group were subjected to microleakage study. Two samples from both the subgroups of the three adhesives were used for scanning electron microscopic examination of the resin–dentin interfacial ultrastructure. Dye leakage scores were subjected to statistical analysis using Kruskal–Wallis and Mann–Whitney U‐tests at significance level of P < 0.05. Results: GB depicted significantly more microleakage which was significantly greater than OB and XV. The double application led to significant decrease in microleakage of GB with no significant effect on the microleakage scores of other two all‐in‐one adhesives, that is OB and XV. Conclusion: Double application of all‐in‐one self‐etch adhesives improves the marginal sealing ability in dentin although it appears to be product dependent. Microsc. Res. Tech. 78:489–494, 2015. © 2015 Wiley Periodicals, Inc.     

Effect of localised charges on nanoscale cylindrical surrounding gate MOSFET: Analog performance and linearity analysis

The paper presents a simulation study of Nanoscale Cylindrical Surrounding Gate (SRG) MOSFET with localised interface charges. The objective of the present work is to study the performance degradation due to hot carrier induced/radiation induced/stress induced damage in the form of localised/fixed charges at the semiconductor/oxide interface of the device. Impact of fixed charges has been studied on the characteristics such as drain current, transconductance and its higher order terms, device efficiency and linearity FOMs. Effect of nature and extension of interface fixed charges has been discussed in detail through extensive simulation. Circuit reliability issues of the device are discussed in terms of DC bias point degradation.     

Synthesis and thermal stability of polyesters and polyamides from β-(2-methoxy-5-methylphenyl) glutaconic acid,diols, and diamines

Some polyester and polyamide resins were prepared by condensing β-(2-methoxy-5-methylphenyl) glutaconic acid with diols and diamines. The polycondensates were characterized by IR, TG, DSC, VPO, and elemental analysis. Some polycondensates were found to be soluble in acetone, dimethylformamide, and dioxane. All polymers were found to decompose in the range of ≈200 to ≈600°C. Their softening points are in the range of ≈ 90 to ≈ 190°C. They are brown black in colour. The kinetics of decomposition were studied. The kinetic parameters were evaluated by the method of Broido. It is observed that the energy of activation of polycondensates depends upon the presence of diol and diamine components in the polymer.