Ferrocene-Based Cationic Surfactants: Surface and Antimicrobial Properties

A novel series of ferrocenyl surfactants was synthesized by the reaction of ferrocene disulfonic acid with different primary and tertiary fatty amines to produce the corresponding ammonium salts Fc[SO₃ ^{− +}NH₃(CH₂) _n CH₃]₂, where n = 9, 11, or 15 and Fc[SO₃^{− +}NH(CH₃)₂(CH₂) _n CH₃]₂, where n = 7 or 11, respectively, and where Fc = ferrocene. Chemical structures were confirmed by microelemental analysis, FTIR, and ¹H NMR spectroscopy. The critical micelle concentration of each prepared surfactant was determined using equilibrium surface tension. Furthermore, air/water interface parameters including effectiveness (π _CMC), efficiency (Pc₂₀), maximum surface excess (Г_max), and minimum surface area (A _min) were determined at 30, 40, and 50 °C. Thermodynamic parameters (ΔG°, ΔS°, and ΔH°) for both micellization and adsorption processes were recorded. The new synthesized surfactants were screened as antimicrobial agents against different bacterial and fungal organisms.     

Enhancement of the optical and mechanical properties of chitosan using Fe<Subscript>2</Subscript>O<Subscript>3</Subscript> nanoparticles

In this work, the optical and mechanical properties of Fe₂O₃ nanoparticles (NPs)/chitosan nanocomposite films have been investigated. Nanocomposite films of different weight ratios of Fe₂O₃ NPs/chitosan (0, 1, 5, 10, 20 and 30 wt%) were fabricated using casting technique. The optical properties of colloidal Fe₂O₃ NPs and Fe₂O₃ NPs/chitosan nanocomposite films were recorded using UV–visible spectrophotometer. As the ratio of Fe₂O₃ NPs to chitosan increases from 0 to 30%, the energy band gap of Fe₂O₃ NPs/chitosan films decreases from 3.16 to 2.11 eV. This decrease is due to quantum confinement effect. The mechanical properties of the nanocomposite films as a function of sweeping temperature were measured using a dynamic mechanical analyzer. An enhancement in storage modulus, stiffness and glass transition temperature (T_g) has been observed as the ratio of Fe₂O₃ NPs/chitosan increases. T_g of Fe₂O₃ NPs/chitosan nanocomposite film shifts towards higher temperature side with respect to pure chitosan film from 152.1 to 166.3?°C as the ratio of Fe₂O₃ NPs/chitosan increases from 0 to 30 wt%. The increase in T_g is mainly attributed to the decrease in free volumes and vacancies in the nanocomposite films as the weight ratio of Fe₂O₃ NPs/chitosan increases.     

Microleakage of oral microflora for porcelain and some porcelain repair materials--in vitro study

Repairing porcelain fractures has become of interest to the dentist. The intra oral fracture of metal-ceramic restorations may be due to inadequate metal support, excessive porcelain thickness, technical flaws, and occlusal forces. Various techniques for intra oral porcelain repair have been suggested. The resin-porcelain junction has been in question since the advent of the porcelain veneer for cast metal restorations. To enhance this, several intermediary products and techniques have been developed to increase the chemical bond between the fractured porcelain and the repair materials. Clinical procedures for porcelain repair has required roughening of porcelain surface with a rotary abrasives, application of silane followed by composite to replace the contour of the restoration (2, 13, 14). Laboratory data suggested that the strong bond of the repair materials was developed.     

Prevention of tooth hypersensitivity caused by the hydrodynamic action of zinc phosphate and composite resin luting cements (SEM) study

This study was done to determine the role of cement liner as a reducing factor to the fluid movement in order to prevent tooth hypersensitivity according to the hydrodynamic theory during cementation of crowns. A total of fourty freshly extracted intact lower molar were selected for this study. After conventional tooth preparation the teeth were sub-divided into four equal groups to identify the role of cement liner in preventing the penetration of used cement into the dentinal tubules. Scanning electron microscopic study proved the efficiency of glass ionomer liner on preventing cement penetration into the dentinal tubules.     

Development of Novel Quinoline-Based Sulfonamides as Selective Cancer-Associated Carbonic Anhydrase Isoform IX Inhibitors

A new series of quinoline-based benzenesulfonamides (QBS) were developed as potential carbonic anhydrase inhibitors (CAIs). The target QBS CAIs is based on the 4-anilinoquinoline scaffold where the primary sulphonamide functionality was grafted at C4 of the anilino moiety as a zinc anchoring group (QBS 13a–c); thereafter, the sulphonamide group was switched to ortho- and meta-positions to afford regioisomers 9a–d and 11a–g. Moreover, a linker elongation approach was adopted where the amino linker was replaced by a hydrazide one to afford QBS 16. All the described QBS have been synthesized and investigated for their CA inhibitory action against hCA I, II, IX and XII. In general, para-sulphonamide derivatives 13a–c displayed the best inhibitory activity against both cancer-related isoforms hCA IX (K_Is = 25.8, 5.5 and 18.6 nM, respectively) and hCA XII (K_Is = 9.8, 13.2 and 8.7 nM, respectively), beside the excellent hCA IX inhibitory activity exerted by meta-sulphonamide derivative 11c (K_I = 8.4 nM). The most promising QBS were further evaluated for their anticancer and pro-apoptotic activities on two cancer cell lines (MDA-MB-231 and MCF-7). In addition, molecular docking simulation studies were applied to justify the acquired CA inhibitory action of the target QBS.     

Influence of copper nanoparticles capped by cationic surfactant as modifier for steel anti-corrosion paints

The synthesized cationic surfactant N-(2-(2-mercaptoacetoxy) ethyl)-N,N-dimethyldodecan-1-aminium bromide (QSH) was used to prepare colloidal copper nanoparticles (CuNPs) in water through the chemical reduction method. The obtained copper nanoparticles were characterized by FTIR spectrum and transmission electron microscopy (TEM). The corrosion performance was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements in addition to the salt spray test. The results obtained from these methods were in good agreement. Results showed that the modified coating provide a good coverage and an additional corrosion protection of the carbon steel.     

An analytical model for silicon MIS/IL solar cells to optimize cell parameters through thermal annealing

A model has been developed which simulates the effect of cell parameters in order to optimize them by controlling the fabrication conditions, namely, annealing time and annealing temperature. Calculation of the efficiency as a function of surface states density D_it, positive fixed oxide charge density Q_f and mobile charge density Q_m, that depend on anealing conditions are carried out. A compromise between D_it and Q_m for different anealing temperatures for high performance cells has been investigated.     

Design and testing of high-density polyethylene nanocomposites filled with lead oxide micro- and nano-particles: Mechanical,thermal, and morphological properties

This research discusses the mechanical behavior and the microstructure of high-density polyethylene (HDPE)-based composites, manufactured using the melt-mixing and thermal-pressing techniques, where HDPE is mixed with various percentages of either bulk lead monoxide (bulk PbO) or PbO nanoparticles (PbO-NPs) acting as fillers. The scanning electron microscope and the field emission transmission electron microscope were utilized to identify the morphology of polymeric composites. Both showed the proper dispersion of PbO in the HDPE matrix without substantial agglomerations. The effect of PbO on the thermal behavior of the HDPE was studied using the thermogravimetric analysis. Tensile tests were implemented to find out how the mechanical characteristics of the composites were affected. Yield stress, % elongation at break, stiffness, tensile energy (toughness), ultimate tensile strength, and ultimate tensile strain were elucidated in this work. The values of stiffness, ultimate tensile strength, and yield stress increased by increasing either the bulk PbO or PbO-NPs' loading up to 40.0 wt % with reference to the hosting matrix. The values of ultimate tensile strain, tensile energy, and % elongation at break of the assembled composites diminished dramatically by increasing the filler's content from 10.0 to 50.0 wt %. Besides, composites with PbO-NPs as a filler were identified as having higher mechanical characteristics than those with bulk PbO for the same wt %. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47812.     

Rhodamine B hydrazide loaded polysulfone fabrics for Cu(II) detection: Morphological and optical properties

Polysulfone-based materials were fabricated as casted films, porous membranes, and nanofibers by solution casting, phase inversion process, and electrospinning technique, respectively. Photoactive rhodamine B hydrazide molecules were loaded into the fabrics either in preloading or postloading processes. The morphological structure of the fabrics was investigated by scanning electron microscopy and the wettability was determined by contact angle measurements. Detailed spectroscopic characterizations of the closed and open forms of rhodamine B was performed both in solution and in the solid-state composite materials. Theoretical investigations supported the depiction of the absorption and emission features of the two forms. The response of the prepared composite materials to Cu(II) ions has been tested by absorption and emission spectroscopy and confocal fluorescence imaging. The most effective materials for Cu(II) detection were found to be polysulfone films prepared by phase inversion and postloaded with 10% rhodamine B hydrazide. These results open the way to the development of composite sensory membranes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48408.     

Tuning photocurrent response through size control of CdSe quantum dots sensitized solar cells

The photovoltaic characterization of CdSe quantum dots sensitized solar cells (QDSSCs) by tuning band gap of CdSe quantum dots (QDs) through size control has been investigated. Fluorine doped tin oxide (FTO) substrates were coated with 20 nm in diameter TiO₂ nanoparticles (NPs). Pre-synthesized colloidal CdSe quantum dots of different sizes (from 4.0 to 5.4 nm) were deposited on the TiO₂-coated substrates using direct adsorption (DA) method. The FTO counter electrodes were coated with platinum, while the electrolyte containing I^?/I ₃ ^? redox species was sandwiched between the two electrodes. The current density-voltage (J-V) characteristic curves of the assembled QDSSCs were measured for different dipping times, and AM 1.5 simulated sunlight. The maximum values of short circuit current density (J_sc) and conversion efficiency (η) are 1.62 mA/cm² and 0.29 % respectively, corresponding to CdSe QDs of size 4.52 nm (542 nm absorption edge) and of 6 h dipping time. The variation of the CdSe QDs size mainly tunes the alignment of the conduction band minimum of CdSe with respect to that of TiO₂ surface. Furthermore, the J_sc increases linearly with increasing intensity of the sun light, which indicates the sensitivity of the assembled cells.