Fabrication of Multifunctional Nanostructured Porous Materials

Nanostructured porous materials generally, and nanoporous noble metals specifically, have received considerable attention due to their superior chemical and physical properties over nanoparticles and bulk counterparts. This dissertation work aims to develop well-established strategies for the preparation of multifunctional nanostructured porous materials based on the combination of inorganic-chemistry, organic-chemistry and electrochemistry. The preparation strategies involved one or more of the following processes: sol-gel synthesis, co-electrodeposition, metal ions reduction, electropolymerization and dealloying or chemical etching. The study did not stop at the preparation limits but extended to investigate the reaction mechanism behind the formation of these multifunctional nanoporous structures in order to determine the different factors controlling the nanoporous structures formation. First, gold-silica nanocomposites were prepared and used as a building blocks for the fabrication of high surface area gold coral electrodes. Well-controlled surface area enhancement, film thickness and morphology were achieved. An enhancement in the electrode’s surface area up to 57 times relative to the geometric area was achieved. A critical sol-gel monomer concentration was also noted at which the deposited silica around the gold coral was able to stabilize the gold corals and below which the deposited coral structures are not stable. Second, free-standing and transferable strata-like 3D porous polypyrrole nanostructures were obtained from chemical etching of the electrodeposited polypyrrole-silica nanocomposite films. A new reaction mechanism was developed and a new structural directing factor has been discovered for the first time. Finally, silver-rich platinum alloys were prepared and dealloyed in acidic medium to produce 3D bicontinuous nanoporous platinum nanorods and films with a nanoporous gold-like structure. The 3D-BC-NP-Pt displayed high surface area, typical electrochemical sensing properties in an aqueous medium, and exceptional electrochemical sensing capability in a complex biofouling environment containing fibrinogen. The 3D-BC-NP-Pt displayed high catalytic activity toward the methanol electro-oxidation that is 30 times higher that of planar platinum and high volumetric capacitance of 400 F/cm3. These findings will pave the way toward the development of high performance and reliable electrodes for catalysis, sensing, high power outputs fuel cells, battery-like supercapacitors and miniaturized device applications

Effect of different visible light curing systems on the color stability of resin cements

The present study aimed to compare the color stability of zirconia cemented veneers, using self-etch adhesive cement after curing with various systems and aging process. Materials and methods: A total of 27 veneers zirconia samples were cemented using resin cement on 27 labially prepared extracted anterior teeth to reach a flat surface, and classified into three groups according to the light curing units (LCU); Group I (Cured with Polywave Ivoclar Bluephase style LCU), Group II (Cured with Polywave Woodpecker iLED LCU), Group III (Cured with Monowave 3M Elipar LCU). Results: Monowave LCU exhibited significantly higher color changes than the polywave LCU ([P \u3c 0.05] [ΔE 2.94 ± 0.44]). Interaction between polywave polymerizing units and resin cement was not significant (P \u3e 0.05). Conclusion: This study concluded that different light curing systems have a significant effect on the final color of resin cement used in cementation of zirconia veneers. Polywave LCUs provide better color stability of zirconia veneers

Azo-Hydrazone Tautomerism and Antimicrobial activity of New substituted Imidazolines and Perimidines

Two new series of 2-{1-[(substitutedphenyl)-hydrazono]-2-oxo-2-phenyl-ethyl}-5,5-diphenyl-3,5-dihydro-imidazol-4-one  and  (1H-Perimidin-2-yl)-[(substitutedphenyl)-hydrazono]-acetic acid ethyl ester were prepared by coupling the diazonium salt of aniline and its derivatives with 2-(2-oxo-2-phenyl-ethylidene)-5,5-diphenyl-imidazolidin-4-one or ethyl 3-dimethylamino-2-(1H-perimidin-2-yl)-propenoate in ethanolic sodium hydroxide solution. The structures of all the newly synthesized compounds were confirmed by spectral (IR, 1H NMR, mass) spectra , and X-ray crystallographic and elemental analyses. Also, the azo-hydrazone tautomerism of these compounds was discussed. In addition, all the newly synthesized compounds were screened for their antibacterial and antifungal activity and the results obtained indicated that some of these compounds exhibited excellent activity

Exocyclic enaminones as building blocks for synthesis of bioactive polyheterocyclic compounds

The reaction of exocyclic enaminones namely, 2-(dimethylaminomethylene)-3,4-dihydro-2H-naphthalen-1-one,  3-(dimethylaminomethylene)-thiochroman-4-one and 2-(dimethyl-aminomethylene)-indane-1,3-dione, each with heterocyclic diazonium salts afforded the respective hydrazones which undergo either in situ dehydrative cyclization or cyclized by heating with acetic acid to give polycyclic compounds. The structure of all the newly synthesized products were confirmed by elemental and spectral (IR, IH NMR, Mass) data. Also, the biological activity of some of the prepared compounds was tested against some microorganisms and promising results were obtained

Towards Environmental Retrofitting of Egyptian Transitional Spaces: Courtyard-Building in Alexandria University, Egypt

Consuming huge amount of energy and emitting large amount of heat can be assumed as one of the main problems facing urban environment in the world today. These problems associated with current high urban density and less of vegetation within urban fabric. For instance, in Egypt, Universities are today facing rising problem of offering more educational spaces especially in large cities such as Cairo and Alexandria. The study thus focuses on Revival Egyptian buildings in Alexandria University based on hierarchical transitional spaces. As Egyptian transitional spaces, such as courtyards historically were essential outdoor spaces for multiple uses and purposes. As part of retrofitting research project of existed transitional spaces in Alexandria University, this paper focused on one parameter which is building height. This is by targeting to find the maximum height of courtyard building with minimum negative effect on air and thermal flow. This simulation is done with consideration to the surrounding urban context in Alexandria University. The simulation approach is based on two years of field measurement of thermal conditions and air velocity in the Universityrsquos transitional spaces. The study is usingfield-measurement data for nurturing the Computational Fluid Dynamics (CFD) model, and for validating the simulation results. The Computational Fluid Dynamics (CFD) study is done by introducing four cases of different building heights to investigating the changing air and thermal flow inside the existed courtyard. nbs

Site-selectivite Synthesis and Tautomerism of Arylazo Derivatives of Pyrazolo[3,4-d]pyrimido-[1,6-b][1,2,4]triazine

A simple synthetic strategy is described for synthesis of the hitherto unreported 5-arylazo-1,3-diphenyl-6-substituted-1H-pyrazolo[3,4-d]pyrimido[1,6-b][1,2,4]triazines 5a-n. The spectral data indicated that the studied compounds exist predominantly in the hydrazone tautomeric form 5A. The site-selectivity and mechanism of the studied reactions are discussed

Effect of excess boron on growth, membrane stability, and functional groups of tomato seedlings

With the scarcity of good quality water, plants like tomatoes will be more susceptible to excess boron (EB) in Mediterranean regions. The effects of EB on the growth, free, semi-bound, and bound boron (B) concentrations, and macromolecules of the Solanum lycopersicum L. cultivar Castle Rock, were investigated in this study. Seedlings were exposed to four levels of EB using boric acid. The results manifested that EB inhibited tomato growth, total water content, and photosynthetic pigments. EB harmed the membrane stability, as seen by increased potassium (K) leakage, UV absorbance metabolites, and electrolyte conductivity (EC) in leaf disc solution. EB raised concentrations of free, semi-bound, and bound forms of B in seedlings. Fourier transform infrared spectroscopy (FTIR) data revealed that EB induced uneven wax deposition, altered the shape of cell walls, and lowered cellulose synthesis in seedlings. EB affected the amide I and amide II indicating damage to the protein pools. These results provide new insights into understanding the specific effects of EB on the functional groups of different macromolecules of tomato seedlings

Assessment of the accuracy of multi-parametric MRI with PI-RADS 2.0 scoring system in the discrimination of suspicious prostatic focal lesions

AbstractObjectivesAssessing the value of Mp-MRI with PI-RAD2.0 in distinguishing between malignant and benign prostatic lesions.Patients & methods55 patients with suspicious prostatic lesions underwent PR examination, PSA tests, TRU/S, and Mp-MRI prostate. Mean age was 62years and imaging data were correlated with histopathological data.ResultsHistopathology results revealed 38 malignant lesions and 17 were benign. DWI showed significant restriction with low ADC value, 0.89±0.24μm2/ms in 30 PZ lesions that diagnosed to be likely malignant, (3–5 score) and 7 benign lesions showed no diffusion abnormality with ADC values, 1.34±0.21μm2/ms which were statistically significantly higher than those of malignant lesions (P<0.001). Of the 18 TZ lesions, T2WI diagnosed 7 to be likely malignant (score 3–5) and 11 were benign (1–2 score). DCE-MRI revealed positive results in 28 PZ and 8 TZ lesions. Adding DCE-MRI to DWI and T2WI score in equivocal lesions raises its score from 3 to 4 in 6/9 lesions that aid in malignant lesions diagnosis. Negative enhancement was noted in 9 PZ and 10 TZ benign lesions (−ve).ConclusionMulti-parametric MRI with PI-RAD V2 scoring system was proved to be non invasive and accurate tool for distinguishing between malignant and benign prostatic lesions