Spherical carbons: Synthesis, characterization and activation processes

Spherical carbons have been prepared through hydrothermal treatment of three carbohydrates (glucose, saccharose and cellulose). Preparation variables such as treatment time, treatment temperature and concentration of carbohydrate have been analyzed to obtain spherical carbons. These spherical carbons can be prepared with particle sizes larger than 10 μm, especially from saccharose, and have subsequently been activated using different activation processes (H3PO4, NaOH, KOH or physical activation with CO2) to develop their textural properties. All these spherical carbons maintained their spherical morphology after the activation process, except when KOH/carbon ratios higher than 4/1 were used, which caused partial destruction of the spheres. The spherical activated carbons develop interesting textural properties with the four activating agents employed, reaching surface areas up to 3100 m2/g. Comparison of spherical activated carbons obtained with the different activating agents, taking into account the yields obtained after the activation process, shows that phosphoric acid activation produces spherical activated carbons with higher developed surface areas. Also, the spherical activated carbons present different oxygen groups’ content depending on the activating agent employed (higher surface oxygen groups content for chemical activation than for physical activation).

Integrin-linked kinase regulates the rate of platelet activation and is essential for the formation of stable thrombi

BACKGROUND: Integrin-linked kinase (ILK) and its associated complex of proteins are involved in many cellular activation processes, including cell adhesion and integrin signaling. We have previously demonstrated that mice with induced platelet ILK deficiency show reduced platelet activation and aggregation, but only a minor bleeding defect. Here, we explore this apparent disparity between the cellular and hemostatic phenotypes. METHODS: The impact of ILK inhibition on integrin αII b β3 activation and degranulation was assessed with the ILK-specific inhibitor QLT0267, and a conditional ILK-deficient mouse model was used to assess the impact of ILK deficiency on in vivo platelet aggregation and thrombus formation. RESULTS: Inhibition of ILK reduced the rate of both fibrinogen binding and α-granule secretion, but was accompanied by only a moderate reduction in the maximum extent of platelet activation or aggregation in vitro. The reduction in the rate of fibrinogen binding occurred prior to degranulation or translocation of αII b β3 to the platelet surface. The change in the rate of platelet activation in the absence of functional ILK led to a reduction in platelet aggregation in vivo, but did not change the size of thrombi formed following laser injury of the cremaster arteriole wall in ILK-deficient mice. It did, however, result in a marked decrease in the stability of thrombi formed in ILK-deficient mice. CONCLUSION: Taken together, the findings of this study indicate that, although ILK is not essential for platelet activation, it plays a critical role in facilitating rapid platelet activation, which is essential for stable thrombus formation.

Measurement of action spectra of light-activated processes

We report on a new experimental technique suitable for measurement of light-activated processes, such as fluorophore transport. The usefulness of this technique is derived from its capacity to decouple the imaging and activation processes, allowing fluorescent imaging of fluorophore transport at a convenient activation wavelength. We demonstrate the efficiency of this new technique in determination of the action spectrum of the light mediated transport of rhodamine 123 into the parasitic protozoan Giardia duodenalis. (c) 2006 Society of Photo-Optical Instrumentation Engineers.

Activaciones patrimoniales e iniciativas museísticas: ¿por quién? y ¿para qué?

[ES] Se suele afirmar que hay dos tipos de patrimonio cultural. Uno, “eterno”, “riguroso”, “irremplazable” o “global”; otro, “contingente”, “flexible”; “sustituible” o “local”. El primero es de la “humanidad”; el segundo, de la “comunidad”. Los trabajos que se presentan en esta publicación, describen y analizan procesos de activación de ese segundo tipo de patrimonio: los intereses y las valorizaciones que han conducido a la patrimonialización o puesta en valor de unos bienes culturales; qué agentes han intervenido en ese proceso; por qué, para qué y cómo lo han llevado a cabo. Se interesan más por el modus operandi que por el opus operatum. Escritos por profesores, investigadores, especialistas y técnicos, los trabajos de esta publicación presentan un conjunto de experiencias europeas y americanas, mostrando un panorama diverso y complejo del campo patrimonial y museístico, así como distintas aproximaciones en función de la posición que ocupa el autor respecto a los bienes culturales.

从字形到语义：跨语言Stroop效应的ERP研究

According to the influential dual-route model of reading (Coltheart, Rastle et al. 2001), there are two routes to access the meaning of visual words: one directly by orthography (orthography-semantic) and the other indirectly via the phonology (phonology-semantic). Because of the dramatic difference between written Chinese and alphabetical languages, it is still on debate whether Chinese readers have the same semantic activation processes as readers of alphabetical languages. In this study, the semantic activation processes in alphabetical German and logographic Chinese were compared. Since the N450 for incongruent color words in the Stroop tasks was induced by the semantic conflict between the meaning of the incongruent color words and color naming, this component could be taken as an index for semantic activation of incongruent color words in Stroop tasks. Two cross-script Stroop experiments were adopted to investigate the semantic activation processes in Chinese and German. The first experiment focused on the the role of phonology, while the second one focused on the realative importance of orthography. Cultural differences in cognitive processing between individuals in western and eastern countries have been found (Nisbett & Miyamoto, 2005). In order to exclude potential differences in basic cognitive processes like visual discrimination capabilities during reading, a visual Oddball experiment with non-lexical materials was conducted with all participants. However, as indicated by the P300 elicited by deviant stimuli in both groups, no group difference was observed. In the first Stroop experiments, color words (e.g., “green”), color-word associates (e.g., “grass”), and homophones of color words were used. These words were embedded into color patches with either congruent color (e.g. word “green” in green color patch) or incongruent colors (e.g. word “green” in either red or yellow or blue color patch). The key point is to observe whether homophones in both languages could induce similar behavioral and ERP Stroop effects to that induced by color words. It was also interesting to observe to which extent the N450 was related to the semantic conflicts. Nineteen Chinese adult readers and twenty German adult readers were asked to respond to the back color of these words in the Stroop experiment in their native languages by pressing the corresponding keys. In the behavioral data, incongruent conditions (incongruent color words, incongruent color-word associates, incongruent homophones) had significantly longer reaction times as compared to corresponding congruent conditions. All incongruent conditions in the Geman group elicited an N450 in the 400 to 500 ms time window. In the Chinese group, the N450 in the same time window was also observed for the incongruent color words and incongruent color-word associates. These results indicated that the N450 was very sensitive to semantic conflict-even words with semantic association to colors (e.g. “grass”) could elicite similar N450. However, the N450 was absent for incongruent homophones of color words in the Chinese group. Instead, in a later time window (600-800 ms), incongruent homophones elicited a positivity over left posterior regions as compared to congruent homophones. Similar positivity was also observed for color words in the 700 to 1000 ms time window in the Chinese group and 600 to 1000 ms time window for incongruent color words and homophones in the Geman group. These results indicate that phonology plays an important role in Geman semantic activation processes, but not in Chinese. In the second Stroop experiment, color words and pseudowords which had similiar visual shape to color words in both languages were used as materials. Another group of eighteen Chinese and twenty Germans were involved in the Stroop experiment in their native languages.The ERPs were recorded during their performance. In the behavioral data, strong and comparable Stroop effects (as counted by substract the reaction times in the congruent conditions from reaction times in the incongruent conditions) were observed. In the ERP data, both incongruent color words and incongruent pseudowords elicited an N450 over the whole brain scalp in both groups. These results indicated that orthography played an equally important role in semantic activation processes in both languages. The results of the two Stroop experiments support the view that the semantic activation process in Chiense readers differs significantly from that in German readers. The former rely mainly on the direct route (orthography-semantic), while the latter use both direct route and incirect route (phonology-semantic). These findings also indicate that the characteritics of different languages shape the semantic activation processes.

Influence of preparation conditions on the characteristics of activated carbons produced in laboratory and pilot scale systems

The central theme of this investigation is to evaluate the feasibility of using bituminous coal as a precursor material for the production of chars and activated carbons using physical and chemical activation processes. The chemical activation process was accomplished by impregnating the raw materials with different dehydrating agents in different ratios and concentrations, prior to heat treatment (ZnCl2, KCl, KOH, NaOH and Fe2(SO4)3·xH2O). Steam activation of the precursor material was adopted for the preparation of activated carbon using physical activation technology. Different types of bituminous coal; namely, contaminated Columbian (contaminated with pet. coke), pure Columbian, Venezuelan and New Zealand bituminous coal were used in the production processes. BET surface area, micropore area, pore size distribution and total pore volume of the chars and activated carbons were determined from N2 adsorption/desorption isotherm, measured at 77 K. Charring conditions, charring temperature of 800 °C and charring time of 4 h, proved to be the optimum conditions for preparing chars. Contaminated Columbian were found to be the best precursor material for the production of char with reasonable physical characteristics (surface area = 138.1 m2 g-1 and total pore volume of 8.656 × 10-0.2 cm3 g-1). An improvement in the physical characteristics of the activated carbons was obtained upon the treatment of coal with dehydrating agents. Contaminated Columbian treated with 10 wt% ZnCl2 displayed the highest surface area and total pore volume (surface area = 231.5 m2 g-1 and total pore volume = 0.1227 cm3 g-1) with well-developed microporisity (micropore area = 92.3 m2 g-1). Venezuelan bituminous coal using the steam activation process was successful in producing activated carbon with superior physical characteristics (surface area = 863.50 m2 g-1, total pore volume = 0.469 cm3 g-1 and micropore surface area = 783.58 m2 g-1).

Design, Manufacture and Performance of Germanium Bipolar Transistors

Germanium NPN bipolar transistors have been manufactured using phosphorus and boron ion implantation processes. Implantation and subsequent activation processes have been investigated for both dopants. Full activation of phosphorus implants has been achieved with RTA schedules at 535?C without significant junction diffusion. However, boron implant activation was limited and diffusion from a polysilicon source was not practical for base contact formation. Transistors with good output characteristics were achieved with an Early voltage of 55V and common emitter current gain of 30. Both Silvaco process and device simulation tools have been successfully adapted to model the Ge BJT(bipolar junction transistor) performance.

Hydrogen-permeation characteristics of a SrCeO3-based ceramic separation membrane:Thermal, ageing and surface-modification effects

Dense ceramics with mixed protonic-electronic conductivity are of considerable interest for the separation and purification of hydrogen and as electrochemical reactors. In this work, the hydrogen permeability of a Sr_0.97Ce_0.9Yb_0.1O_{3 - δ} (SCYb) membrane with a porous Pt catalytic layer on the hydrogen feed-exposed side has been studied over the temperature range 500-804 °C employing Ar as the permeate sweep gas. A SiO₂-B₂O₃-BaO-MgO-ZnO-based glass-ceramic sealant was successfully employed to seal the membrane to the dual-chamber reactor. After 14 h of exposure to 10% H₂:90% N₂ at 804 °C, the H₂ flux reached a maximum of 33 nmol cm^{- 2} s^{- 1}, over an order of magnitude higher than that obtained on membranes of similar thickness without surface modification. The permeation rate then decreased slowly and moderately on annealing at 804 °C over a further 130 h. Thereafter, the flux was both reproducible and stable on thermal cycling in the range 600-804 °C. The results indicate an important role of superficial activation processes in the flux rate and suggest that hydrogen fluxes can be further optimised in cerate-based perovskites. © 2009 Elsevier B.V. All rights reserved.

Eliminación de compuestos causantes de olores mediante adsorbentes/catalizadores obtenidos a partir de lodos de depuradora

El aumento de la cantidad de lodos y las dificultades inherentes a su aplicación agrícola y/o disposición en vertederos, hace necesario encontrar nuevas alternativas para su gestión. A nivel europeo, hoy en día se tiende hacia la aplicación de tratamientos térmicos (incineración, pirólisis y gasificación) que permiten una valoración energética de los lodos, si bien generan un residuo sólido que sigue siendo necesario gestionar. El problema medioambiental provocado por (malos) olores resulta difícil de abordar de una manera genérica, teniendo en consideración la propia naturaleza del olor y sus posibles causas. Los olores en las EDARs son provocados básicamente por la degradación de la materia orgánica en condiciones anaeróbicas y se detectan en todas las operaciones unitarias en diferentes niveles de concentración. Esta tesis incidiendo en ambos aspectos, tiene por objeto investigar la valorización de lodos como materiales precursores de adsorbentes/ catalizadores para la eliminación de olores en el entorno de las EDARs, maximizando la reutilización de los lodos. Para la realización de los experimentos se han seleccionado lodos procedentes de tres EDARs situadas en la región de Girona (SC, SB, SL) que difieren en cuanto al tratamiento de los lodos. Ambas muestras han sido caracterizadas con el fin de determinar las diferencias más importantes en los lodos de partida. Los parámetros de caracterización incluyen el análisis de composición química (análisis elemental e inmediato, determinación contenido en cenizas, medida pH, DRX, FT-IR, SEM / EDX) así como análisis de superficie (adsorción de N2 y CO2). En primer lugar los lodos caracterizados han sido sometidos a diferentes tratamientos térmicos de gasificación y pirólisis y los adsorbentes/ catalizadores obtenidos se han probado como adsorbentes para la eliminación de H2S. Como consecuencia de este estudio, se ha desechado el uso de uno de lodos (SC) puesto que se obtenían resultados muy similares a (SB), a continuación el estudio se centró en el lodo de SL. Con este objetivo se han preparado 12 muestras 6 de ellas pirolizadas y 6 gasificadas en el rango de temperaturas que comprende 600-1100 ºC. Posteriormente las muestras han sido caracterizadas y se ha determinado la capacidad de eliminación (x/M) del H2S. Los resultados muestran que hemos sido capaces de obtener unos materiales que si bien, presentan un bajo desarrollo de porosidad dan lugar a valores de capacidades de eliminación elevados y comparables a carbones y materiales adsorbentes comerciales (Centaur, Sorbalit). Las elevadas eficiencias de eliminación se atribuyen básicamente a la presencia de especies catalíticamente activas tales como los óxidos mixtos de calcio y hierro determinados por DRX en las muestras tratadas térmicamente. El segundo bloque de resultados se centra la mejora de las propiedades texturales de estos materiales adsorbentes. Con este objetivo se llevaron acabo procesos de activación física con CO2 y química con H3PO4 e hidróxidos alcalinos (NaOH y KOH), que hasta el momento no se había probado con este tipo de precursores. Los resultados indican que la activación física (CO2) y química (H3PO4) no son unos buenos métodos para la obtención de adsorbentes altamente porosos con este tipo de materia prima bajo las condiciones probadas, sin embargo la activación con hidróxidos alcalinos da lugar a materiales adsorbentes con superficies específicas de hasta 1600 m2g-1. En el caso de la activación con hidróxidos, tanto el incremento de la relación agente activante/ precursor como el incremento de la temperatura producen un descenso del rendimiento, al mismo tiempo que incrementan el valor de SBET. Los materiales resultantes de la activación con hidróxidos alcalinos se han probado como adsorbentes/ catalizadores para la eliminación de H2S. Los resultados indican que un incremento del área superficial no es indicativo de un aumento de la capacidad de eliminación dada la naturaleza ácida de estos materiales obtenidos. Con el fin de contrarrestar el efecto ácido de estos materiales se han realizado los mismos ensayos añadiendo NaOH al lecho de reacción llegando a valores de x/M de hasta 450 mgg-1. Posteriormente también se han realizado ensayos de eliminación de NH3 con algunas de estas muestras, y los resultados obtenidos de x/M son del orden de carbones activados comerciales. Los materiales adsorbentes obtenidos tras la activación con hidróxidos alcalinos se convierten en materiales muy atractivos para ser utilizados como adsorbentes/ catalizadores de múltiples contaminantes (COVs, Hg...).

Adsorção do corante amarelo reativo BF-4G 200% por argila esmectita

This study aimed to evaluate the potential use of smectite clays for color removal of textile effluents. The experiments were performed by testing exploratory/planning method factorial and fractional factorial where the factors and levels are predetermined. The smectite clays were used originating from gypsum hub of the region Araripe-PE, and the dye used was Reactive Yellow BF-4G 200%. The smectite clay was collected and transported to the Laboratory of Soil Physics of UFRPE, where it held its preparation through air drying, lump breaking and classification in sieve to then submit it to the adsorption process. Upon completion of 22 complete factorial design it was concluded that the values of (96, 96,5 and 95,8%) corresponding to the percentage of of removal for "in-kind", chemically and thermally activated, respectively and adsorbed amounts of (4,80, 4,61 and 4,74 mg/g) for three clays. Showed that the activation processes used did not increase the adsorption capacity of smectite clay. The kinetic data were best fitted to the Freundlich isotherm, with an exponential distribution of active sites and that shows above the Langmuir equation for adsorption of cations and anions by clays. The kinetic model that best adapted to the results was the pseudosecond order model. In the factorial design study 24-1, at concentrations up to 500 mg/L obtains high percentage of color removal (92,37, 90,92 and 93,40%) and adsorbed amount (230,94, 227,31 and 233,50 mg/g) for three clays. The kinetic data fitted well to Langmuir and Freundlich isotherms. The kinetic model that best adapted to the results was the pseudosecond order model

O papel da escola na vida de adolescentes vítimas de violência sexual: risco e proteção

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ativação da ligação c-h no metano por espécies MOm n+ (M = Nb, Fe; m = 0, 1; n = 0, 1, 2): estrutura eletrônica, mecanismo de reação e reatividade

The need for renewal and a more efficient use of energy resources has provided an increased interest in studies of methane activation processes in the gas phase by transition metal oxides. In this respect, the present work is an effort to assess , by means of a computational standpoint, the reactivity of NbOm n+ and FeOm n+ (m = 1, 2, n = 0, 1, 2) oxides in the activation process of the methane C-H bond, which corresponds to the first rate limiting step in the process of converting methane to methanol. These oxides are chosen, primarily, because the iron oxides are the most experimentally studied, and iron ions are more abundant in biological mediums. The main motive for choosing niobium oxides is the abundance of natural reserves of this mineral in Brazil (98%), especially in Minas Gerais. Initially, a thorough investigation was conducted, using different theoretical methods, to analyze the structural and electronic properties of the investigated oxides. Based on these results, the most reliable methodology was selected to investigate the activation process of the methane C-H bond by the series of iron and niobium oxides, considering all possible reaction mechanisms known to activate the C-H bond of alkanes. It is worth noting that, up to this moment and to our knowledge, there are no papers, in literature , investigating and comparing all the mechanisms considered in this work. I n general, the main results obtained show different catalytic tendencies and behaviors throughout the series of monoxides and dioxides of iron and niobium. An important and common result found in the two studies is that the increase in the load on the metal center and the addition of oxygen atoms to the metal, clearly favor the initial thermodynamics of the reaction, i.e., favor the approach of the metal center to methane, distorting its electron cloud and, thereby, decreasing its inertia. Comparing the two sets of oxides, we conclude that the iron oxides are the most efficient in activating the methane C-H bond. Among the iron oxides investigated, FeO + showed better kinetic and thermodynamic performance in the reaction with methane, while from the niobium oxides and ions NbO 2+ and NbO2 2+, showed better catalytic efficiency in the activation of the methane C-H bond.

Functional neuroimaging of emotional learning and autonomic reactions

This article provides a selective overview of the functional neuroimaging literature with an emphasis on emotional activation processes. Emotions are fast and flexible response systems that provide basic tendencies for adaptive action. From the range of involved component functions, we first discuss selected automatic mechanisms that control basic adaptational changes. Second, we illustrate how neuroimaging work has contributed to the mapping of the network components associated with basic emotion families (fear, anger, disgust, happiness), and secondary dimensional concepts that organise the meaning space for subjective experience and verbal labels (emotional valence, activity/intensity, approach/withdrawal, etc.). Third, results and methodological difficulties are discussed in view of own neuroimaging experiments that investigated the component functions involved in emotional learning. The amygdala, prefrontal cortex, and striatum form a network of reciprocal connections that show topographically distinct patterns of activity as a correlate of up and down regulation processes during an emotional episode. Emotional modulations of other brain systems have attracted recent research interests. Emotional neuroimaging calls for more representative designs that highlight the modulatory influences of regulation strategies and socio-cultural factors responsible for inhibitory control and extinction. We conclude by emphasising the relevance of the temporal process dynamics of emotional activations that may provide improved prediction of individual differences in emotionality.

Induced oleoresin biosynthesis in grand fir as a defense against bark beetles.

Grand fir (Abies grandis) saplings and derived cell cultures are useful systems for studying the regulation of defensive oleoresinosis in conifers, a process involving both the constitutive accumulation of resin (pitch) in specialized secretory structures and the induced production of monoterpene olefins (turpentine) and diterpene resin acids (rosin) by nonspecialized cells at the site of injury. The pathways and enzymes involved in monoterpene and diterpene resin acid biosynthesis are described, as are the coinduction kinetics following stem injury as determined by resin analysis, enzyme activity measurements, and immunoblotting. The effects of seasonal development, light deprivation, and water stress on constitutive and wound-induced oleoresinosis are reported. Future efforts, including a PCR-based cloning strategy, to define signal transduction in the wound response and the resulting gene activation processes are delineated.

Well-defined mesoporosity on lignocellulosic-derived activated carbons

Activated carbons with a highly developed mesoscale cavitation-linked structure have been prepared from natural products (e.g. peach stones) by combining chemical and physical activation processes. Characterization results show that these materials exhibit a large “apparent” surface area (∼1500 m2/g) together with a well-defined mesoporous structure, i.e. large cavities connected to the external surface through narrower mesoporous necks (cavitation effects).