Synthesis and Crystal Structure of 4-Methyl-6H-pyrido[3,2,1-<Emphasis Type="Italic">jk</Emphasis>]carbazol-6-one

Abstract  The synthesis, NMR and X-ray structure of 4-methyl-6H-pyrido[3,2,1-jk]carbazol-6-one—a potential DNA intercalator are reported. The compound crystallizes in the orthorhombic Pbca space group with unit cell parameters: a = 7.775(8), b = 15.113(7), c = 19.849(7) ?, V = 2332.8(3) ?³, Mr = 233.26 and Z = 8. In the three-dimensional arrangement of the molecules no classical hydrogen bonds were found; weak π···π and C–H···O interactions are responsible for the packing of the molecules in the crystal structure. Index Abstract  In the three-dimensional arrangement of the title compound no classical hydrogen bonds were found; weak π···π and C–H···O interactions are responsible for the packing of the molecules in the crystal structure.      

A reduced basis approach to large‐scale pseudospectra computation

For studying spectral properties of a nonnormal matrix $A\in {\mathbb{C}}^{n\times n}$, information about its spectrum σ(A) alone is usually not enough. Effects of perturbations on σ(A) can be studied by computing ε‐pseudospectra, i.e. the level sets of the resolvent norm function $\mathsf{g}(z)=\Vert {(zI?A)}^{?1}{\Vert }_2$. The computation of ε‐pseudospectra requires determining the smallest singular values ${\sigma }_{\min }(zI?A)$ for all z on a portion of the complex plane. In this work, we propose a reduced basis approach to pseudospectra computation, which provides highly accurate estimates of pseudospectra in the region of interest, in particular, for pseudospectra estimates in isolated parts of the spectrum containing few eigenvalues of A. It incorporates the sampled singular vectors of zI ? A for different values of z, and implicitly exploits their smoothness properties. It provides rigorous upper and lower bounds for the pseudospectra in the region of interest. In addition, we propose a domain splitting technique for tackling numerically more challenging examples. We present a comparison of our algorithms to several existing approaches on a number of numerical examples, showing that our approach provides significant improvement in terms of computational time.     

Novel properties of PES fabrics modified by corona discharge and colloidal TiO2 nanoparticles

The objective of this study was to highlight the potential application of the corona discharge at atmospheric pressure for the surface activation of polyester (PES) fabrics in order to improve the binding efficiency of colloidal TiO₂ nanoparticles. The obtained nanocomposite textile materials provide desirable level of UV protection, self‐cleaning properties, and photodegradation activity. The measured UV protection factor (UPF) of fabrics corresponds to UPF rating of 50+, designating the maximum UV protection. Additionally, the total photodegradation of methylene blue in aqueous solution was achieved after 24 hr of UV illumination and this capability was preserved and even improved after four repeated cycles. The results showed that the corona treated PES fabrics loaded with TiO₂ nanoparticles had considerably enhanced the overall efficiency compared to PES fabrics loaded only with TiO₂ nanoparticles. Copyright © 2009 John Wiley & Sons, Ltd.     

The effects of running gravitational coupling on rotating black holes

In this work we investigate the consequences of running gravitational coupling on the properties of rotating black holes. Apart from the changes induced in the space-time structure of such black holes, we also study the implications to Penrose process and geodetic precession. We are motivated by the functional form of gravitational coupling previously investigated in the context of infra-red limit of asymptotic safe gravity theory. In this approach, the involvement of a new parameter \({\tilde{\xi }}\) in this solution makes it different from Schwarzschild black hole. The Killing horizon, event horizon and singularity of the computed metric is then discussed. It is noticed that the ergosphere is increased as \({\tilde{\xi }}\) increases. Considering the black hole solution in equatorial plane, the geodesics of particles, both null and time like cases, are explored. The effective potential is computed and graphically analyzed for different values of parameter \({\tilde{\xi }}\). The energy extraction from black hole is investigated via Penrose process. For the same values of spin parameter, the numerical results suggest that the efficiency of Penrose process is greater in quantum corrected gravity than in Kerr Black Hole. At the end, a brief discussion on Lense–Thirring frequency is also done.     

Kinetic modeling and optimization of maceration and ultrasound-extraction of resinoid from the aerial parts of white lady’s bedstraw (Galium mollugo L.)

In this paper, extraction of resinoid from the aerial parts of white lady’s bedstraw (Galium mollugo L.) using an aqueous ethanol solution (50% by volume) was studied at different temperatures in the absence and the presence of ultrasound. This study indicated that ultrasound-assisted extraction was effective for extracting the resinoid and gave better resinoid yields at lower extraction temperature and in much shorter time than the maceration. A phenomenological model was developed for modeling the kinetics of the extraction process. The model successfully describes the two-step extraction consisting of washing followed by diffusion of extractable substances and shows that ultrasound influences only the first step. The extraction process was optimized using response surface methodology (RMS) and artificial neural network (ANN) models. For the former modeling, the second-order polynomial equation was applied, while the second one was performed by an ANN-GA combination. The high coefficient of determination and the low MRPD between the ANN prediction and the corresponding experimental data proved that modeling the extraction process in the absence and the presence of ultrasound using ANN was more accurate than RSM modeling. The optimum extraction temperature was determined to be 80 and 40 °C, respectively for the maceration and the ultrasound-assisted extraction, ensuring the highest resinoid yield of 22.0 g/100 g in 4 h and 25.1 g/100 g in 30 min, which agreed with the yields obtained experimentally for the same time (21.7 and 25.3 g/100 g, respectively).     

Epitaxial growth on porous GaAs substrates

We report on the electrochemical preparation of porous GaAs substrates in fluoride-iodide aqueous electrolytes for the lattice mismatched epitaxial growth from the vapor phase. The aim is to gain control over the uniformity of the pore nucleation layer and pore branching below this layer to achieve structures with a high degree of porosity and periodicity while leaving minimum damage on the substrate surface. Layers of In_xGa_1-xAs with varying In content are grown on GaAs substrates with different pore geometries and depths. Substantial differences in the surface morphology and photoluminescence efficiency of the layers grown on porous and conventional substrates are observed.     

Testing of a hot- and cold-wire probe to measure simultaneously the speed and temperature in supercritical CO2 flow

The use of hot-wire anemometry in carbon dioxide flow under supercritical conditions has been analyzed and implemented for the first time. A two-sensor probe to simultaneously measure streamwise velocity and temperature in this flow has been designed and constructed. A calibration and test flow loop that can provide supercritical state conditions above the critical point has been also designed, fabricated and tested. The temperature and velocity flow fields of the flow loop can be varied at constant pressure. It has been found that, above the pseudo-critical temperature, the velocity sensor response fits King’s cooling law with a high correlation coefficient. The dependence of the King’s law parameters on temperature can be accurately presented with second or higher order polynomial or exponential fits, depending on the extent of the temperature range. Below the pseudocritical temperature the data is scattered, and the variation with temperature of the King’s law parameters, determined from calibration, is irregular. The influence on this data scatter of the strong variation of the fluid properties near the critical point is analyzed, and a possibility to reduce it is proposed. The temperature sensor response both above and below the pseudocritical temperature is similar to the response under normal conditions. It is linear with a very high correlation coefficient between the calibration data and the fitted curve. It is also shown that the temperature response is not affected by variation of the flow’s speed.     

Fluorescent dendritic polymers and nanostructured coatings for the detection of chemical warfare agents and other analytes

Polyamidoamine (PAMAM) dendrimers of generations zero (G0) to four (G4), and a hyperbranched polyurea (HB‐PU), were functionalized with 1,5‐dansyl (1,5‐D), 2,5‐dansyl (2,5‐D), 2,6‐dansyl (2,6‐D) and nitrobenzofurazan (NBD) fluorophores that change their fluorescence emission wavelength in response to chemical environment, and the resulting dendritic polymers were characterized by MALDI‐TOF mass spectrometry, ¹H NMR, ¹³C NMR, and fluorescence spectroscopy. Fluorophore‐functionalized dendritic polymers were then reacted further with 3‐acryloxypropyldimethoxymethylsilane (AOP‐DMOMS) at various fluorophore to DMOMS substitution ratios. The resulting materials were cast onto glass slides, and cured into robust nanostructured coatings. Coatings with 50% fluorophore–50% DMOMS substitution showed the strongest fluorescence and the best physical properties. Coated coupons were tested against a wide range of analytes including the chemical warfare agent simulants dimethyl methylphosphonate (DMMP) and chloroethylethylsulfide (CEES), and the water‐methanol‐ethanol series. It was found that the ability of the coatings to distinguish between analytes decreased with increasing cross‐link density for both dendrimer and hyperbranched polymer‐based coatings. It was also found that the percent fluorophore substitution and the type of dendritic polymer carrying the fluorophore had no significant effect upon fluorescence emission wavelength, but fluorescence emission wavelength became less dependent upon solvent with increasing dendrimer generation and molecular mass. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5101–5115, 2009     

Laryngopharyngeal Symptoms and Gastroesophageal Reflux Disease

The incidence of gastroesophageal reflux disease (GERD) in patients with laryngopharyngeal symptoms is greater than expect. A prospective study was performed to investigate the incidence of gastroesophageal reflux disease (GERD) and laryngopharyngeal reflux (LPR) in patients with laryngopharyngeal symptoms. Laryngologic evaluation with nasopharyngeal and laryngeal endoscopy and gastroenterologic evaluation with esophagogastroduodenoscopy including measurement of pH value were performed in 46 patients. Therapeutic intervention included general antireflux precautions and antireflux medication, and eradication of Helicobacter pylori in selected cases. Posterior laryngitis was present in 33 patients. GERD was present in 25 patients, hiatus hernia in 4 patients, H pylori-positive gastritis in 11 patients, and Barrett's metaplasia in 2 patients. Increasing evidence shows that GERD may cause laryngopharyngeal symptoms. Otherwise laryngopharyngeal symptoms can be predictors of GERD. Medical antireflux treatment is also effective for laryngopharyngeal symptoms.