Antioxidant properties of Teaw (Cratoxylum formosum Dyer) extract in soybean oil and emulsions

The antioxidant activity of an extract from Teaw (Cratoxylum formosum Dyer) leaves was studied in soybean oil and soybean oil-in-water emulsions. Samples containing the extract or reference antioxidants including chlorogenic acid, which comprises 60% of the Teaw extract, were stored at 60 degrees C and analyzed periodically for peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) to allow both hydroperoxides and hydroperoxide degradation products to be monitored. Chlorogenic acid and the Teaw extract were more effective than a-tocopherol in inhibiting lipid oxidation in bulk oil but were less effective in an oil-in-water emulsion in accordance with the polar paradox. The PV/TBARS ratio for oil samples containing chlorogenic acid was higher than for alpha-tocopherol and BHT because chlorogenic acid inhibits both hydroperoxide formation by radical scavenging and hydroperoxide decomposition by metal chelation. The importance of the metal-chelating activity in retarding hydroperoxide decomposition was confirmed by studying the decomposition of oil samples containing added ferric ions. The PV/TBARS ratio was higher for citric acid than for (x-tocopherol in the presence of added ferric chloride, but the order was reversed in samples lacking ferric chloride. Samples containing added chlorogenic acid gave the highest PV/TBARS ratios both in the presence and absence of ferric ions. The PV/TBARS ratios for the samples containing antioxidants fell rapidly to lower values in a soybean oil-in-water emulsion than in the soybean oil. This was due to increased hydroperoxide decomposition in the emulsion at the same PV. The Teaw extract contained 12% oil-soluble components, which contributed to a slightly higher oil-water partition coefficient than that of chlorogenic acid. The antioxidant activity of the aqueous phase of the Teaw extract was reduced more than that of chlorogenic acid by partitioning of the oil-soluble components into oil, which showed that the less-polar components contributed to the antioxidant activity of the Teaw extract in aqueous media.

Multistep electrochemical reduction path of clusters [Os3(CO)10(α-diimine)]: comparison of electrochemical and photochemical Os-Os(α-diimine) bond cleavage

Electrochemical reduction of the triangular clusters [Os-3(CO)(10)(alpha-dimine)] (alpha-dimine = 2,2'-bipyridine (bpy), 2,2'-bipyrimidine (bpym)) and [Os-3(CO)(10)(mu-bpym) ReBr(CO)(3)] produces primarily the corresponding radical anions. Their stability is strongly determined by the pi acceptor ability of the reducible alpha-dimine ligand, which decreases in the order mu-bpym > bpym >> bpy. Along this series, increasing delocalisation of the odd electron density in the radical anion over the Os(alpha-dimine) chelate ring causes weakening of the axial (CO)(4)Os-Os(CO)(2)(alpha-dimine) bond and its facile cleavage for alpha-diimine = bpy. In contrast, the cluster radical anion is inherently stable for the bridging bpym ligand, the strongest pi-acceptor in the studied series. In the absence of the partial delocalisation of the unpaired electron over the Re( bpym) chelate bond, the Os-3-core of the radical anion remains intact only at low temperatures. Subsequent one-electron reduction of [Os-3(CO)(10)(bpym)](center dot-) at T = 223 K gives the open-triosmium core (= Os-3*) dianion, [Os-3*(CO)(10)(bpym)](2-). Its oxidation leads to the recovery of parent [Os-3(CO)(10)( bpym)]. At room temperature, [Os-3*( CO)(10)(bpym)](2-) is formed along a two-electron (ECE) reduction path. The chemical step (C) results in the formation of an open- core radical anion that is directly reducible at the cathodic potential of the parent cluster in the second electrochemical (E) step. In weakly coordinating tetrahydrofuran, [Os-3*(CO)(10)( bpym)](2-) rapidly attacks yet non- reduced parent cluster molecules, producing the relatively stable open- core dimer [Os-3*(CO)(10)(bpym)](2)(2-) featuring two open- triangle cluster moieties connected with an ( bpym) Os - Os( bpym) bond. In butyronitrile, [Os-3*( CO)(10)(bpym)](2-) is stabilised by the solvent and the dimer [Os-3*(CO)(10)(bpym)](2)(2-) is then mainly formed by reoxidation of the dianion on reverse potential scan. The more reactive cluster [Os-3(CO)(10)(bpy)] follows the same reduction path, as supported by spectroelectrochemical results and additional valuable evidence obtained from cyclic voltammetric scans. The ultimate process in the reduction mechanism is fragmentation of the cluster core triggered by the reduction of the dimer [Os-3*(CO)(10)(alpha- diimine)](2)(2-). The products formed are [Os-2(CO)(8)](2-) and {Os(CO)(2)(alpha- diimine)}(2). The latter dinuclear fragments constitute a linear polymeric chain [Os( CO)(2)(alpha-dimine)] n that is further reducible at the alpha-dimine ligands. For alpha-dimine = bpy, the charged polymer is capable of reducing carbon dioxide. The electrochemical opening of the triosmium core in the [Os-3( CO)(10)(alpha-dimine)] clusters exhibits several common features with their photochemistry. The same Os-alpha-dimine bond dissociates in both cases but the intimate mechanisms are different.

Photochromic dithienylethene derivatives containing Ru(II) or Os(II) metal units. Sensitized photocyclization from a triplet state

Efficient photocyclization from a low-lying triplet state is reported for a photochromic dithienylperfluorocyclopentene with Ru(bpy)(3) units attached via a phenylene linker to the thiophene rings. The ring-closure reaction in the nanosecond domain is sensitized by the metal complexes. Upon photoexcitation into the lowest Ru-to-bpy (MLCT)-M-1 state followed by intersystem crossing to emitting (MLCT)-M-3 states, photoreactive (IL)-I-3 states are populated by an efficient energy-transfer process. The involvement of these (IL)-I-3 states explains the quantum yield of the photocyclization, which is independent of the excitation wavelength but decreases strongly in the presence of dioxygen. This behavior differs substantially from the photocyclization of the nonemissive dithienylperfluorocyclopentene free ligand, which occurs from the lowest (IL)-I-1 state on a picosecond time scale and is insensitive to oxygen quenching. Cyclic voltammetric studies have also been performed to gain further insight into the energetics of the system. The very high photocyclization quantum yields, far above 0.5 in both cases, are ascribed to the strong steric repulsion between the bulky substituents on the dithienylperfluorocyclopentene bridge bearing the chelating bipyridine sites or the Ru(bpy)(3) moieties, forcing the system to adopt nearly exclusively the reactive antiparallel conformation. In contrast, replacement of both Ru(II) centers by Os(II) completely prevents the photocyclization reaction upon light excitation into the low-lying Os-to-bpy (MLCT)-M-1 state. The photoreaction can only be triggered by optical population of the higher lying (IL)-I-1 excited state of the central photochromic unit, but its yield is low due to efficient energy transfer to the luminescent lowest (MLCT)-M-3 state.

Bibliographic analysis of persuasive systems: techniques, methods and domains of application

This paper presents findings of our study on peer-reviewed papers published in the International Conference on Persuasive Technology from 2006 to 2010. The study indicated that out of 44 systems reviewed, 23 were reported to be successful, 2 to be unsuccessful and 19 did not specify whether or not it was successful. 56 different techniques were mentioned and it was observed that most designers use ad hoc definitions for techniques or methods used in design. Hence we propose the need for research to establish unambiguous definitions of techniques and methods in the field.

Fault tolerant decentralised K-Means clustering for asynchronous large-scale networks

The K-Means algorithm for cluster analysis is one of the most influential and popular data mining methods. Its straightforward parallel formulation is well suited for distributed memory systems with reliable interconnection networks, such as massively parallel processors and clusters of workstations. However, in large-scale geographically distributed systems the straightforward parallel algorithm can be rendered useless by a single communication failure or high latency in communication paths. The lack of scalable and fault tolerant global communication and synchronisation methods in large-scale systems has hindered the adoption of the K-Means algorithm for applications in large networked systems such as wireless sensor networks, peer-to-peer systems and mobile ad hoc networks. This work proposes a fully distributed K-Means algorithm (EpidemicK-Means) which does not require global communication and is intrinsically fault tolerant. The proposed distributed K-Means algorithm provides a clustering solution which can approximate the solution of an ideal centralised algorithm over the aggregated data as closely as desired. A comparative performance analysis is carried out against the state of the art sampling methods and shows that the proposed method overcomes the limitations of the sampling-based approaches for skewed clusters distributions. The experimental analysis confirms that the proposed algorithm is very accurate and fault tolerant under unreliable network conditions (message loss and node failures) and is suitable for asynchronous networks of very large and extreme scale.

Systemic Inflammatory Reaction After Silicone Breast Implant

Systemic inflammation after augmentation mammaplasty with modern silicone implants is not currently recognized. In a prospective controlled study, C-reactive protein and other variables were monitored, aiming to test this hypothesis in a young cohort of patients. Females (18-30 years old, BMI = 18.5-30 kg/m(2), N = 52) were consecutively recruited for breast implant (n = 24, Group I) and for abdominal liposuction (n = 28, Group II/Controls). Patients were interviewed at baseline and followed until 6 months after operation. Variables included demographic and clinical information, surgical outcome, inflammatory markers and autoantibodies. Operations were well tolerated, without surgical or infectious complications. Mean prosthesis size was 258 +/- A 21 ml (range = 220-280) and mean aspirate of liposuction was 1972 +/- A 499 ml (range = 1200-3000). Preoperative, 2-month, and 6-month C-reactive protein concentrations for breast implant patients were 1.3 +/- A 1.2, 4.8 +/- A 3.0, and 4.3 +/- A 6.4 mg/l and for liposuction 3.5 +/- A 2.7, 3.5 +/- A 2.1, and 2.2 +/- A 2.2 mg/l, respectively. Change at 2 months was significant (p = 0.001). Autoantibody investigation failed to reveal remarkable aberrations, except for anticardiolipin elevation, which was nearly symmetrical in the two groups. C-reactive protein levels increased after operation and correlated with proinflammatory and procoagulatory indices. A mild increase in anticardiolipin IgM occurred but differences between populations were lacking. Despite excellent cosmetic outcomes and lack of complications, acute phase reaction could signal ongoing immunogenicity of silicone and long-term monitoring is recommended.

Ex Situ Scanning Electrochemical Microscopy (SECM) Investigation of Bismuth- and Bismuth/Lead Alloy Film-Modified Gold Electrodes in Alkaline Medium

Scanning electrochemical microscopy (SECM) in feedback mode was employed to characterise the reactivity and microscopic peculiarities of bismuth and bismuth/lead alloys plated onto gold disk substrates in 0.1 molL(-1) NaOH solutions. Methyl viologen was used as redox mediator, while a platinum microelectrode was employed as the SECM tip. The metal films were electrodeposited ex situ from NaOH solutions containing either bismuth ions only or both bismuth and lead ions. Approach curves and SECM images indicated that the metal films were conductive and locally reactive with oxygen to provide Bi(3+) and Pb(2+) ions. The occurrence of the latter chemical reactions was verified by local anodic stripping voltammetry (ASV) at the substrate solution interface by using a mercury-coated platinum SECM tip. The latter types of measurements allowed also verifying that lead was not uniformly distributed onto the bismuth film electrode substrate. These findings were confirmed by scanning electron microscopy images. The surface heterogeneity produced during the metal deposition process, however, did not affect the analytical performance of the bismuth coated gold electrode in anodic stripping voltammetry for the determination of lead in alkaline media, even in aerated aqueous solutions. Under the latter conditions, stripping peak currents proportional to lead concentration with a satisfactory reproducibility (within 5% RSD) were obtained.

Modelo experimental de lesões intra-epiteliais e de adenocarcinoma ductal pancreático induzidos por 7,12-dimetilbenzantraceno em camundongos

INTRODUÇÃO: O adenocarcinoma de pâncreas apresenta um mau prognóstico. A utilização de modelos experimentais é necessária para a compreensão do comportamento biológico tumoral, principalmente das lesões precoces (neoplasias intra-epiteliais pancreáticas - NIPan) e para o desenvolvimento de opções terapêuticas. OBJETIVO: Avaliar a carcinogênese pancreática induzida por 7,12-dimetilbenzantraceno (DMBA), em camundongos, aplicando a classificação das neoplasias intra-epiteliais pancreáticas. MÉTODOS: 90 camundongos machos, mus musculus, da cepa CF1, foram submetidos à laparotomia mediana e 1 mg de DMBA foi implantado na porção cefálica do pâncreas. Os animais foram divididos em dois grupos, com eutanásia em 30 e 60 dias. Em seguida, o pâncreas foi retirado, fixado em formalina e foram confeccionadas lâminas coradas com hematoxilina eosina. Os cortes histológicos foram avaliados por dois patologistas de acordo com os seguintes critérios: pâncreas normal, hiperplasia reacional, NIPan 1A, NIPan 1B, NIPan 2, NIPan 3 e carcinoma. As alterações inflamatórias também foram analisadas. RESULTADOS: A avaliação patológica evidenciou, no grupo de 30 dias: 4 (16,7%) animais com hiperplasia reativa, 16 (66,6%) com NIPan e 4 (16,7%) com adenocarcinoma. No grupo de 60 dias: 10 (27,1%) animais com hiperplasia reativa, 13 (35,1%) com NIPan e 14 (37,8%) com adenocarcinoma. A diferença entre os grupos apresentou significância estatistística (P < 0,05 – teste exato de Fisher). A prevalência de alterações inflamatórias em 30 dias foi: pancreatite aguda (n=11), pancreatite crônica (n=5) e inflamação dependente da bolsa (n=8). No grupo de 60 dias 11 espécimes apresentavam pancreatite aguda e 26 pancreatite crônica. CONCLUSÕES: O modelo experimental com DMBA em camundongos, induz neoplasia intra-epitelial pancreática e adenocarcinoma ductal histologicamente semelhantes ao carcinoma pancreático em humanos. Este modelo pode ser utilizado na investigação da carcinogênese com enfoque na progressão molecular das lesões precursoras até o adenocarcinoma.

Coordenação entre as respostas da catalase e da ascorbato peroxidade em folhas de feijão caupi submetidas a diferentes fontes de peróxido de hidrogênio

The plants are often exposed to variations in environmental conditions that may trigger metabolic disturbances leading to a consequent loss in productivity of crops. These stressful conditions usually induce an accumulation of reactive oxygen species (ROS) in the cell, a condition known how oxidative stress. Among these species, hydrogen peroxide (H2O2) is an important molecule involved in numerous signaling mechanisms. The present study aimed to understand the relationship between the different enzymatic mechanisms of elimination of H2O2 by catalase (CAT) and ascorbate peroxidase (APX) in leaf tissues of seedlings of the species Vigna unguiculata L. Walp, under conditions of oxidative stress induced by application of CAT inhibitor, 3-amino-1,2,4-triazole (3-AT), and H2O2 itself on the roots. Three experiments were conducted. The first experiment was performed applying the compound 3-AT (5 mM) during the time (hours). In the second experiment, seedlings were exposed to different concentrations of H2O2 (2.5, 5.0, 7.5, 10 mM) for 48 h. The third strategy included the pre-treatment with H2O2 (2.5 mM) for 24 h, followed by subsequent treatment with the inhibitor 3-AT and recovery control condition. Treatment with 3-AT causes a strong inhibition of CAT activity in leaf tissues accompanied by an increase of activity of APX. However a decrease in oxidative damage to lipids is not observed as indicated by TBARS. It was observed that activity of APX is directly linked to the content of peroxide. Inductions in the activities of CAT and APX were observed mainly in the seedlings treated with 2.5 mM H2O2. This can be associated with a decrease in oxidative damage to lipids. In contrast, one same tendency was not observed in treatments with higher concentrations of this ROS. These results suggest that the concentration of 2.5 mM H2O2 can induce responses antioxidants later in seedling cowpea. This concentration when applied as pre-treatment for 24 h promoted an induction systems removers CAT and APX, both in activity and in terms of gene expression. However this increment was not observed in the recovered plants and the plants subsequently subjected to 3-AT. Additionally, the pretreatment was not sufficient to attenuate the inhibition of CAT activity and oxidative damage to lipids caused by the subsequent application of this inhibitor. The results showed that the application of 3-AT and H2O2 in the root systems of seedlings of cowpea promote changes in the parameters analyzed in leaf tissues that indicate a direct response to the presence of these factors or systemic signaling mecanisms. H2O2 appears to activate the responses of two antioxidant systems in this study thar does not promote greater protection in case of additional treatment with 3-AT. This demonstrates the importance of the CAT system. In this work, complete results indicate that there is a difference between the signaling and the effects caused by exposure to H2O2 and by treatment with 3-AT

Um protocolo de comunicação multicast na camada de aplicação com Consciência de Localização

Internet applications such as media streaming, collaborative computing and massive multiplayer are on the rise,. This leads to the need for multicast communication, but unfortunately group communications support based on IP multicast has not been widely adopted due to a combination of technical and non-technical problems. Therefore, a number of different application-layer multicast schemes have been proposed in recent literature to overcome the drawbacks. In addition, these applications often behave as both providers and clients of services, being called peer-topeer applications, and where participants come and go very dynamically. Thus, servercentric architectures for membership management have well-known problems related to scalability and fault-tolerance, and even peer-to-peer traditional solutions need to have some mechanism that takes into account member's volatility. The idea of location awareness distributes the participants in the overlay network according to their proximity in the underlying network allowing a better performance. Given this context, this thesis proposes an application layer multicast protocol, called LAALM, which takes into account the actual network topology in the assembly process of the overlay network. The membership algorithm uses a new metric, IPXY, to provide location awareness through the processing of local information, and it was implemented using a distributed shared and bi-directional tree. The algorithm also has a sub-optimal heuristic to minimize the cost of membership process. The protocol has been evaluated in two ways. First, through an own simulator developed in this work, where we evaluated the quality of distribution tree by metrics such as outdegree and path length. Second, reallife scenarios were built in the ns-3 network simulator where we evaluated the network protocol performance by metrics such as stress, stretch, time to first packet and reconfiguration group time

Use of a titanium device in lateral sinus floor elevation: an experimental study in monkeys

Aim: To evaluate the effect of a space-maintaining device fixed to the lateral wall of the maxillary sinus after the elevation of the sinus mucosa on bone filling of the sinus cavity. Material and methods: Immediately after the elevation of the maxillary sinus Schneiderian membrane accomplished through lateral antrostomy in four monkeys, a titanium device was affixed to the lateral sinus wall protruding into the sinus cavity to maintain the mucosa elevated without the use of grafting material. The healing of the tissue around the implants was evaluated after 3 and 6 months. Ground sections were prepared and analyzed histologically. Results: The void under the elevated sinus membrane, originally filled with the blood clot, was reduced after 3 as well as after 6 months of healing of about 56% and 40.5%, respectively. In seven out of eight cases, the devices had perforated the sinus mucosa. The formation of mineralized bone and bone marrow amounted to about 42% and 69% after 3 and 6 months, respectively. The connective tissue represented about 53% and 23% of the newly formed tissue after 3 and 6 months, respectively. Conclusions: New bone formation was found below the devices. However, shrinkage of the newly formed tissue was observed both after 3 and 6 months of healing. Hence, the space-maintaining function of the devices used in the present study has to be questioned.

Hydrochemistry and weathering rates on Corumbatai River basin, São Paulo State, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Seeding of PMN powders made by the Pechini method

The partial oxalate method, with the columbite route, associated with the Pechini method, was used to obtain a very fine ceramic powder at low temperature. Using this route it was possible to obtain a very reactive powder and to synthesize a lead magnesium niobate (PMN) powder with up to 100% of perovskite phase at a lower temperatures than the PbO melting point. The influence of the BaTiO3 and PbTiO3 seeds in the phase formation, along with time and temperature during the PMN calcination, was also investigated. The amount of 2% of BaTiO3 seeds promoted PMN powder formation with 100% of perovskite phase and a very narrow particle size distribution. (C) 2001 Elsevier B.V. Ltd and Techna S.r.l. All rights reserved.

Hormonal therapy in the senescence: Prostatic microenvironment structure and adhesion molecules

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)