Comparison of the interfacial properties of Eugenia uniflora and Triticum vulgaris lectins

We have investigated the interfacial and dielectric properties of EuniSL, a recently purified lectin obtained from seeds of Eugenia uniflora (EuniSL), through surface pressure (Pi) and surface potential (DeltaV) measurements of its floating monolayers at the 2.0相似文献   

Structural and Morphological Characterization of Pt/WO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>–ZrO<Subscript>2</Subscript> Catalysts

Abstract  Catalysts of Pt/WO _x –ZrO₂ type with 1 wt% of Pt and 10, 15 and 20 wt% of tungsten were synthesized and characterized. The structural and morphological features of these catalysts were studied. The samples were synthesized by impregnation method and calcined at 600 °C, 700 °C and 800 °C. The characterizations were carried out using different techniques: X-ray diffraction, Raman spectroscopy, scanning electronic microscopy, nitrogen adsorption measurement and refinement of their crystalline structures by Rietveld method. X-ray diffraction patterns revealed the formation ZrO₂ and WO₃ crystalline structures and its crystallite size were determined. The zirconium oxide crystallized into tetragonal and monoclinic phases and tungsten trioxide crystallized into monoclinic phase. Crystalline WO₃ and amorphous WO _x species were detected by Raman spectra. Index Abstract  Catalysts of Pt/WO _x –ZrO₂ type with 1 wt% of Pt and 10, 15 and 20 wt% of tungsten were synthesized and characterized. The structural and morphological features of these catalysts were studied. The samples were synthesized by impregnation method and calcined at 600 °C, 700 °C and 800 °C. The characterizations were carried out using different techniques: X-ray diffraction, Raman spectroscopy, scanning electronic microscopy, nitrogen adsorption measurement and refinement of their crystalline structures by Rietveld method. X-ray diffraction patterns revealed the formation ZrO₂ and WO₃ crystalline structures and its crystalline size were determined. The zirconium oxide crystallized into tetragonal and monoclinic phases and tungsten trioxide crystallized into monoclinic phase. Crystalline WO₃ and amorphous WO _x species were detected by Raman spectra.     

Low‐temperature Raman spectra of racemate DL‐Alanine crystals

Raman spectra of DL ‐Alanine crystals were investigated in the 50–3200 cm⁻¹ spectral region for temperatures ranging from 15 to 295 K. The crystalline structure of DL ‐Alanine represents a rare example of an amino acid racemate crystallizing in a non‐centrosymmetric space group. From this study, we have observed changes in the wavenumber of modes associated with both rocking of CO₂⁻ and skeletal vibrations. On the other hand, neither changes in the modes associated to CH or CH₃ vibrations nor substantial modifications of the lattice modes of the crystal were observed. Such result indicates slight changes of the CO₂ group orientation without observation of a solid–solid phase transition in the DL ‐Alanine crystal. Copyright © 2009 John Wiley & Sons, Ltd.     

(Co, Zn)O compound obtained from ZnTe vapor deposition on Co/Si substrates

(Co, Zn)O compound has been obtained by a non-expensive synthesis route. ZnTe thin films were obtained by isothermal close space sublimation on the Co thin layer previously sputtered on silicon substrates. After the annealing process in humid ambient cobalt atoms diffusion and Zn oxidation were obtained besides partial Te evaporation. The detailed characterization of the samples by using XRD, RBS, AFM, XPS, VSM and MFM techniques point to the formation of room temperature ferromagnetic Co _x Zn_(1−x)O phase (x<0.15). This ferromagnetic behavior is mainly attributed to Co atoms substituting Zn atoms in the ZnO network.     

Alterations in the fat body and midgut of Culex quinquefasciatus larvae following exposure to different insecticides

This study describes morphological alterations in the fat body and midgut of Culex quinquefasciatus larvae following exposure to different insecticides. To this end, both third and fourth instars of C. quinquefasciatus larvae were exposed for 30 and 60 min to organophosphate (50 ppb), pyrethroids (20 and 30 ppb), and avermectin derivates (1.5 and 54 ppb). Following incubation, pH measurements of the larvae gut were recorded. The fat body and midgut were also analyzed by light and transmission electron microscopy. These studies demonstrate a decrease in the pH of the larvae anterior midgut following exposure to all of the tested insecticides. Histochemical tests revealed a strong reaction for neutral lipids in the control group and a marked decrease in the group exposed to cypermethrin. Furthermore, a weak reaction with acidic lipids in larvae exposed to deltamethrin, temephos, ivermectin and abamectin was also observed. Insecticide-exposed larvae also exhibited cytoplasm granule differences, relative to control larvae. Finally, we noted a small reduction in microvilli size in the apex of digestive cells, although vesicles were found to be present. The destructive changes in the larvae were very similar regardless of the type of insecticide analyzed. These data suggest that alterations in the fat body and midgut are a common response to cellular intoxication.     

In vitro photodynamic antimicrobial chemotherapy in dentine contaminated by cariogenic bacteria

The development of a method to ensure bacterial-free substrates without extensive cavity preparation would be highly useful to dentistry, since there is no currently available effective method for killing residual bacteria in dentinal tissue. This randomized in vitro study determined parameters for using toluidine blue O (TBO) with a light-emitting diode (LED) for dentine caries disinfection and monitored intrapulpal/periodontal temperatures during irradiation. Occlusal human dentine slabs were immersed in Streptococcus mutans culture for demineralization induction. Slabs were allocated to 10 groups (n = 15), which were treated with 0.1 mg ml⁻¹ TBO with 5 min of incubation time or 0.9% NaCl solution for 5, 10 or 15 min, and submitted or not to irradiation for 5, 10 or 15 min (47, 94, and 144 J/cm²). Before and after treatments, dentine samples were analyzed with regard to S. mutans counts. In whole teeth, temperature in pulp and periodontium was measured by thermocouples during irradiation. Kruskal-Wallis/Student-Newman-Keuls, and ANOVA/Tukey test were respectively utilized to compare log reductions and temperature rises between groups. Bacterial reduction was observed when dentine was exposed to both TBO and LED at all irradiation times, as well as to LED alone for 10 and 15 min. Temperature increases lower than 2°C were observed for either pulp or periodontium. Concluding, LED combined with TBO is a safe and effective approach for dentine caries disinfection. Nevertheless, additional studies should be conducted to determine the influence of the irradiation in S. mutans viability in dentinal surface/tubules.     

A primal dual modified subgradient algorithm with sharp Lagrangian

We apply a modified subgradient algorithm (MSG) for solving the dual of a nonlinear and nonconvex optimization problem. The dual scheme we consider uses the sharp augmented Lagrangian. A desirable feature of this method is primal convergence, which means that every accumulation point of a primal sequence (which is automatically generated during the process), is a primal solution. This feature is not true in general for available variants of MSG. We propose here two new variants of MSG which enjoy both primal and dual convergence, as long as the dual optimal set is nonempty. These variants have a very simple choice for the stepsizes. Moreover, we also establish primal convergence when the dual optimal set is empty. Finally, our second variant of MSG converges in a finite number of steps.     

Effect of Bee Pollen on the Mechanical and Thermal Properties of Starch Films

The use of casein, starch and bee pollen as biodegradable materials has been promise. The objective of this work was the development and characterization of films containing casein, pollen and starch. The films were obtained by casting process and the solvent evaporation was performed at 40 °C/24 h. The films characterization was carried out by microscopy, thermal analysis, opacity test, mechanical properties and barrier methods. The starch films presented heterogeneous on microscopy analysis. The thermal behaviors of pollen films were similar. The formulation containing only pollen 3% was unable to form film. The introduction of pollen in starch film formulation improved the mechanical characteristic and thermal stability of films.     

Modified coupling agents based on thiourea, immobilized onto silica. Thermodynamics of copper adsorption

New silylating agents synthesized by incorporating the thiourea molecule into precursor agents containing increasing numbers of basic nitrogen atoms, 3-aminopropyltriethoxysilane, N-[3-(trimethoxysilyl)propyl]-ethylenediamine and N-[3-(trimethoxysilyl)propyl]diethylenetri-amine, through a solvent-free methodology were characterized before being successfully immobilized onto silica gel. The spectroscopic results support the elemental analysis, demonstrating that the thiourea molecule reacted in such a way as to maintain free amino groups. NMR data for carbon and silicon nuclei eflucidated the structural features associated with the incorporated chains and their bonds to the silica skeleton, with formation of covalent silicon-carbon bonds. Thermogravimetric data correlated with the degree of functionalization, which was also obtained from elemental analysis. The available basic nitrogen and sulfur atoms attached to the incorporated pendant chains have the ability to coordinate copper to give 1.10, 0.47 and 1.25 mmol g⁻¹ as maximum adsorption capacities for the samples prepared with the silanes containing one, two and three nitrogen atoms on their structures. The thermodynamic data for copper/basic center interactions at the solid/liquid interface were determined through calorimetric titration, and the set of data demonstrated favorable systems for all three newly synthesized derivatized silicas, as shown by exothermic enthalpic data, which yield negative Gibbs free energies for removal of this cation from aqueous solutions by all the newly synthesized materials.