Uncovering false positives on a virtual screening search for cruzain inhibitors

Some unexpected promiscuous inhibitors were observed in a virtual screening protocol applied to select cruzain inhibitors from the ZINC database. Physical-chemical and pharmacophore model filters were used to reduce the database size. The selected compounds were docked into the cruzain active site. Six hit compounds were tested as inhibitors. Although the compounds were designed to be nucleophilically attacked by the catalytic cysteine of cruzain, three of them showed typical promiscuous behavior, revealing that false positives are a prevalent concern in VS programs. (C) 2007 Elsevier Ltd. All rights reserved.

Photocatalyst TiO(2)-Co: the effect of doping depth profile on methylene blue degradation

In this work, we study the effect of doping depth profile on the photocatalytic and surface properties of TiO(2) films. Two thin film layers of TiO(2) (200 nm) and Co (5 nm), respectively, were deposited by physical evaporation on glass substrate. These films were annealed for 1 s at 100 and 400 A degrees C and the Co layer was removed by chemical etching. Atomic force microscopy (AFM) phase images showed changes in the surface in function of thermal treatment. The grazing-incidence X-ray fluorescence (GIXRF) measurements indicated that the thermal treatment caused migration of Co atoms to below the surface, the depths found were between 19 and 29 nm. The contact angle showed distinct values in function of the doped profile or Co surface concentration. The UV-vis spectra presented a red shift with the increasing of thermal treatment. Photocatalytical assays were performed by methylene blue discoloration and the higher activity was found for TiO(2)-Co treated at 400 A degrees C, the ESI-MS showed the fragments formed during the methylene blue decomposition.

Adsorption of the diazo dye Direct Red 23 onto a zinc oxide surface: A spectroscopic study

The adsorption of the diazo dye Direct Red 23 onto a zinc oxide surface at 30 degrees C in the dark was investigated. The color reduction was monitored by spectrophotometry at 503 run. The FTIR and Raman spectra of the Direct Red 23 adsorption as a function of ZnO concentration were registered. From the PM3 semi-empirical calculations of the atomic charge density and dipole moment of the Direct Red 23 molecule, it was demonstrated that the azo, dye molecule may be adsorbed onto the ZnO Surface through molecule geometry modifications, enhancing the interfacial area causing a variation in the bonding frequencies. (C) 2009 Elsevier B.V. All rights reserved.

Hybrid photocatalysts for the degradation of trichloroethylene in air

Hybrid photocatalysts based on an adsorbent SiMgOx and a photocatalyst TiO(2) were developed in a plate shape. The ceramic surface was coated with TiO(2) by the slip-casting technique. The effect of the support in the photocatalytic degradation of trichloroethylene (TCE) was analyzed by modifying TiO(2) loading and the layer thickness. Photocatalysts were characterised by N(2) adsorption-desorption, mercury intrusion porosimetry, SEM, UV-vis spectroscopy and XRD. A direct relationship between the TiO(2) content and the photocatalytic activity was observed up to three layers of TiO(2) (0.66 wt.%). Our results indicate that intermediate species generated on the TiO(2) layer can migrate through relatively long distances to react with the OH(-) surface groups of the support. By increasing the TiO(2) loading of the photocatalyst two effects were observed: trichloroethylene conversion is enhanced, while the efficiency of the oxidation process is decreased at expenses of increasing the selectivity to COCl(2) and dichloroacetylchloride (DCAC). The results are discussed in terms of the layer thickness, TiO(2) amount, TCE conversion and CO(2), and COCl(2) selectivity. (C) 2009 Elsevier B.V. All rights reserved.

Electrocombustion of humic acid and removal of algae from aqueous solutions

This paper reports experiments involving the electrochemical combustion of humic acid (HA) and removal of algae from pond water. An electrochemical flow reactor with a boron-doped diamond film anode was used and constant current experiments were conducted in batch recirculation mode. The mass transfer characteristics of the electrochemical device were determined by voltammetric experiments in the potential region of water stability, followed by a controlled current experiment in the potential region of oxygen evolution. The average mass transfer coefficient was 5.2 x 10(-5) m s(-1). The pond water was then processed to remove HA and algae in the conditions in which the reaction combustion occurred under mass transfer control. To this end, the mass transfer coefficient was used to estimate the initial limiting current density applied in the electrolytic experiments. As expected, all the parameters analyzed here-solution absorbance at 270 nm, total phenol concentration and total organic carbon concentration-decayed according to first-order kinetics. Since the diamond film anode successfully incinerated organic matter, the electrochemical system proved to be predictable and programmable.

Removal of phenol in high salinity media by a hybrid process (activated sludge plus photocatalysis)

The degradation of phenol by a hybrid process (activated sludge + photocatalysis) in a high salinity medium (50 g L-1 of chloride) has been investigated. The sludge used from a municipal wastewater facility was adapted to the high salt concentrations prior to use. The photocatalytic conditions were optimized by means of a factorial experimental design. TiO2 P25 from Degussa was used as the photocatalyst. The initial phenol concentration was approximately 200 mg L-1 and complete removal of phenol and a mineralization degree above 98% were achieved within 25 h of treatment (24 h of biological treatment and I h of photocatalysis). From HPLC analyses, five hydroxylated intermediates formed during oxidation have been identified. The main ones were catechol and hydroquinone, followed by 1,2,4-benzenetriol, 2-hydroxy- 1,4-benzoquinone, and pyrogallol, in this order. No formation of organochlorine compounds was observed. Therefore, the proposed hybrid process showed itself to be suited to treat phenol in the presence of high contents of salt. (c) 2007 Elsevier B.V. All rights reserved.

A comparative study of the electrogeneration of hydrogen peroxide using Vulcan and Printex carbon supports

A comparative study of two different conductive carbon-black pigments, Vulcan XC-72 R and Printex L6, for the electrogeneration of hydrogen peroxide (H(2)O(2)) by reducing dissolved oxygen in an alkaline solution was performed. The materials were physically characterized by X-ray diffraction (XRD), Fourier transform infrared attenuated total reflection (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). XRD shows the presence of SO(2) and ATR-FTIR technique indicates a difference in NO and SO(2) functional groups between the two carbon pigments. XPS indicated presence of SO and NO and more oxygenated acid species on Printex L6. A rotating ring-disk electrode was used for electrochemical analysis of the oxygen reduction reaction (ORR). The results showed that the Printex L6 was better than Vulcan XC-72 R for H(2)O(2) production. Results also indicate that the number of electrons transferred in the ORR for Printex L6 and Vulcan XC-72 R were 2.2 and 2.9, respectively, while the percentages of H(2)O(2) formed were 88% and 51%. Scanning electrochemistry microscopy images confirmed the higher amount of H(2)O(2) formed in the Printex L6 pigment. Printex L6 was shown to be a more promising for H(2)O(2) production than Vulcan XC-72 R, while the latter was shown to have more potential for fuel cells. (C) 2011 Elsevier Ltd. All rights reserved.

TiO(2)-PHOTOCATALYZED DEGRADATION OF PHENOL IN SALINE MEDIA IN AN ANNULAR REACTOR: HYDRODYNAMICS, LUMPED KINETICS, INTERMEDIATES, AND ACUTE TOXICITY

The photocatalytic degradation of phenol in aqueous suspensions of TiO(2) under different salt concentrations in an annular reactor has been investigated. In all cases, complete removal of phenol and mineralization degrees above 90% were achieved. The reactor operational parameters were optimized and its hydrodynamics characterized in order to couple mass balance equations with kinetic ones. The photodegradation of the organics followed a Langmuir-Hinshelwood-Hougen- Watson lumped kinetics. From GC/MS analyses, several intermediates formed during oxidation have been identified. The main ones were catechol, hydroquinone, and 3-phenyl-2-propenal, in this order. The formation of negligible concentrations of 4-chlorophenol was observed only in high salinity medium. Acute toxicity was determined by using Artemia sp. as the test organism, which indicated that intermediate products were all less toxic than phenol and a significant abatement of the overall toxicity was accomplished, regardless of the salt concentration.

A Contour-based Separation of VerticallyAttached Traffic Signs

This report presents an algorithm for locating the cut points for and separatingvertically attached traffic signs in Sweden. This algorithm provides severaladvanced digital image processing features: binary image which representsvisual object and its complex rectangle background with number one and zerorespectively, improved cross correlation which shows the similarity of 2Dobjects and filters traffic sign candidates, simplified shape decompositionwhich smoothes contour of visual object iteratively in order to reduce whitenoises, flipping point detection which locates black noises candidates, chasmfilling algorithm which eliminates black noises, determines the final cut pointsand separates originally attached traffic signs into individual ones. At each step,the mediate results as well as the efficiency in practice would be presented toshow the advantages and disadvantages of the developed algorithm. Thisreport concentrates on contour-based recognition of Swedish traffic signs. Thegeneral shapes cover upward triangle, downward triangle, circle, rectangle andoctagon. At last, a demonstration program would be presented to show howthe algorithm works in real-time environment.

Vitpunktsförskjutningens påverkan på ICC-profiler vid användande av optiska vitmedel

The connection between fluorescence and color management still is a relatively unexplored area. Thefollowing composition analyses the theory that when printing on fluorescent ink jet paper using ICCprofilesa more yellow print will appear. In theory the ICC-profile compensate for blue light that fluorescefrom the paper with the complementary color, yellow. The human eye apprehands this fluorescentlight as white.When categorizing a number of ink jet qualities some tests to indicate change of color in the final printwere made. Five qualities were chosen for further analyses, each with different white point. TheTC3.5CMYK target was prined on an ink jet printer and measured with different filters for the measurementequipment, GretagMacbeth Spectrolino. U- and UV-filters were used during the testings.From the measurement data ICC-profiles were made to make it possible to watch how the profiles compensatefor the blue change of color that appeared in the data. Although a distinct change of color intoblue were discernible in the measured data there is no evident proof that this cause a final print thatis more yellow. Other conclusions and results are to be read at the end of this composition.

Performance Evaluation of Different PV-Array Configurations under Weak Light Conditions and Partial Shadings

The paper analyses empirical performance data of five commercial PV-plants in Germany. The purpose was on one side to investigate the weak light performance of the different PV-modules used. On the other hand it was to quantify and compare the shading losses of different PV-array configurations. The importance of this study relies on the fact that even if the behavior under weak light conditions or the shading losses might seem to be a relatively small percentage of the total yearly output; in projects where a performance guarantee is given, these variation can make the difference between meeting or not the conditions.When analyzing the data, a high dispersion was found. To reduce the optical losses and spectral effects, a series of data filters were applied based on the angle of incidence and absolute Air Mass. To compensate for the temperature effects and translate the values to STC (25°C), five different methods were assessed. At the end, the Procedure 2 of IEC 60891 was selected due to its relative simplicity, usage of mostly standard parameters found in datasheets, good accuracy even with missing values, and its potential to improve the results when the complete set of inputs is available.After analyzing the data, the weak light performance of the modules did not show a clear superiority of a certain technology or technology group over the others. Moreover, the uncertainties in the measurements restrictive the conclusiveness of the results.In the partial shading analysis, the landscape mounting of mc-Si PV-modules in free-field showed a significantly better performance than the portrait one. The cross-table string using CIGS modules did not proved the benefits expected and performed actually poorer than a regular one-string-per-table layout. Parallel substrings with CdTe showed a proper functioning and relatively low losses. Among the two product generations of CdTe analyzed, none showed a significantly better performance under partial shadings.