Optical properties of nickel(II)-azo complexes thin films for potential application as high-density recordable optical recording media

Smooth thin films of three kinds of nickel(II)-azo complexes were prepared by the spin-coating method. Absorption spectra of the thin films on K9 glass substrate in the 300-600 nn wavelength region were measured. Optical constants (complex refractive index N = n + ik) and thickness of the thin films prepared on single-crystal silicon substrate in the 300-600 nm wavelength region were investigated on rotating analyzer-polarizer type of scanning ellipsometer, and dielectric constants epsilon (epsilon = epsilon(1) + i epsilon(2)), absorption coefficients a as well as reflectance R of thin films were then calculated at 405 nm. In addition, in order to examine the possible use of nickel(II)-azo complex thin film as an optical recording medium, one of the nickel(II)-azo complex thin film prepared on K9 glass substrate with an Ag reflective layer was also studied by atomic force microscopy and static optical recording. The results show that the nickel(II)-azo complex thin film is smooth and has a root mean square surface roughness of 2.25 nm, and the recording marks on the nickel(II)-azo complex thin film are very clear and circular, and their size can reach 200 nn or less. (c) 2006 Elsevier Ltd. All rights reserved.

Efeitos da atividade física de baixa intensidade na estrutura das túnicas íntima e média da aorta em ratos espontaneamente hipertensos (SHR)

O exercício contínuo de baixa intensidade é capaz de atenuar a hipertrofia da célula muscular lisa da parede da aorta de ratos espontaneamente hipertensos (SHR), e parece atuar sobre a distribuição de fibras oxitalânicas, elaunínicas e elásticas. As alterações funcionais das grandes artérias relacionadas com a idade, deposição de colágeno e elastina na parede arterial e a elasticidade, são também melhoradas com a atividade física. No presente trabalho objetivamos estudar os efeitos da atividade física aeróbica de baixa intensidade no remodelamento estrutural da artéria aorta em modelo de hipertensão genética de ratos SHR. Através da análise da distribuição das fibras oxitalânicas, elaunínicas e elásticas na aorta dos animais controles e SHR submetidos ou não a atividade física de baixa intensidade. Foram utilizados 32 ratos, sendo 16 ratos SHR machos e 16 ratos normotensos Wistar Kyoto (WKY) machos com 8 semanas de idade. Ratos machos foram alocados em 4 grupos: WKY sedentário (WKY-SED), WKY exercitado (EX-WKY), SHR sedentário (SED-SHR), e SHR exercitado (EX-SHR). Os ratos sedentários foram limitados à atividade na caixa, enquanto que os ratos exercitados foram submetidos a um exercício de 1 h / dia, 5 dias / semana. Esses grupos passaram pelo protocolo de atividade física de 20 semanas e a pressão arterial foi mensurada semanalmente (PA). As aortas foram colhidas e processadas para microscopia de luz, microscopia eletrônica e western blotting. Foram realizadas as colorações orcinol neo-fucsina e resorcina-fucsina de Weigert. No grupo hipertenso, o exercício mantém a PA em um nível relativamente semelhante ao inicio do protocolo, mostrando a capacidade de prevenir o aumento da PA ao longo das 20 semanas. No grupo dos animais hipertensos não tratados, a PA aumenta. A PA aumentou progressivamente nos ratos SED-SHRs atingindo 1894 mmHg, mas o exercício físico impediu este processo. Ao final do experimento a PA nos ratos EX-SHRs foi similar o dos ratos WKY (1184 vs. 1144 mmHg), respectivamente. Observou-se maior expressão de elastina e maior distribuição de fibras oxitalânicas, elaunínicas e elásticas em animais que foram submetidos ao protocolo de exercício físico. A porcentagem de fibras elásticas e oxitalânicas foi menor em SED-SHR comparado com SED-WKY, mas o exercício físico aumentou a porcentagem dessas fibras em ambos os grupos. Através da imuno-histoquímica ultra-estrutural para elastina e fibrilina, os grupos EX-WKY e EX-SHR apresentaram uma marcação mais intensa para elastina e fibrilina. Animais hipertensos que não sofreram o protocolo de exercício físico apresentam espessura da parede da aorta maior que a dos animais que sofreram o exercício. O número de lamelas elásticas, bem como as fibras oxitalânicas e elaunínicas, é maior no grupo EX-SHR, em relação ao SED-SHR. Os grupos exercitados tiveram maior expressão de eNOS que seus respectivos grupos sedentários, e as células endoteliais apresentaram características morfológicas preservadas. A associação da atividade física com modelos de hipertensão genética mostra que o exercício físico tem efeitos benéficos nessa situação, uma vez que atenua a hipertensão e o remodelamento adverso da parede da aorta.

Role of saphenous vein wall in the pathogenesis of primary varicose veins

UNLABELLED: Varicose veins may be due to weakness of the vein wall as a result of structural problems. There are conflicting findings in the literature about these problems especially concerning collagen, elastin and smooth muscle cells content. The aim of this study was to look at the structural abnormalities of varicose veins (with and without valvular incompetence).

MATERIALS AND METHODS: We studied 70 specimens of long saphenous veins from 35 patients (24 with varicose and 11 with normal veins). Two specimens were taken from each vein approximately 3-4 cm from the saphenofemoral junction. Vein specimens were processed for histological and electron microscopic studies. Both qualitative and quantitative analyses were performed to assess the degree of wall changes. Using the image analyzer, contents of collagen, elastin and smooth muscle cells, in addition to intimal and medial thickness, were measured.

RESULTS: Light microscopy revealed significant increase in intimal and medial thickness and collagen content of media and significant decrease in elastin content in varicose veins compared with normal veins. There was no statistical significant difference between varicose veins with and without saphenofemoral valve incompetence. Electron microscopy showed marked degenerative changes in intima and media of varicose veins.

CONCLUSION: The findings in our study supported the theory of primary weakness of the vein wall as a cause of varicosity. This weakness is due to intimal changes, disturbance in the connective tissue components and smooth muscle cells.

Microwave activation of the electro-oxidation of glucose in alkaline media

The oxidation of glucose is a complex process usually requiring catalytically active electrode surfaces or enzyme modified electrodes. In this study the effect of high intensity microwave radiation on the oxidation of glucose in alkaline solution at Au, Cu, and Ni electrodes is reported. Calibration experiments with the Fe(CN)(6)(3-/4-) redox system in aqueous 0.1 M NaOH indicate that strong thermal effects occur at both 50 and 500 mu m diameter electrodes with temperatures reaching 380 K. Extreme mass transport effects with mass transport coefficients of k(mt) > 0.01 m s(-1) (or k(mt) > 1.0 cm s(-1)) are observed at 50 mu m diameter electrodes in the presence of microwaves. The electrocatalytic oxidation of glucose at 500 mu m diameter Au, Cu, or Ni electrodes immersed in 0.1 M NaOH and in the presence of microwave radiation is shown to be dominated by kinetic control. The magnitude of glucose oxidation currents at Cu electrodes is shown to depend on the thickness of a pre-formed oxide layer. At 50 mu m diameter Au, Cu, or Ni electrodes microwave enhanced current densities are generally higher, but only at Au electrodes is a significantly increased rate for the electrocatalytic oxidation of glucose to gluconolactone observed. This rate enhancement appears to be independent of temperature but microwave intensity dependent, and therefore non-thermal in nature. Voltammetric currents observed at Ni electrodes in the presence of microwaves show the best correlation with glucose concentration and are therefore analytically most useful.

Microwave activation of the electro-oxidation of glucose in alkaline media

The oxidation of glucose is a complex process usually requiring catalytically active electrode surfaces or enzyme-modified electrodes. In this study the effect of high intensity microwave radiation on the oxidation of glucose in alkaline solution at Au, Cu, and Ni electrodes is reported. Calibration experiments with the Fe(CN)63–/4– redox system in aqueous 0.1 M NaOH indicate that strong thermal effects occur at both 50 and 500 µm diameter electrodes with temperatures reaching 380 K. Extreme mass transport effects with mass transport coefficients of kmt > 0.01 m s–1(or kmt > 1.0 cm s–1) are observed at 50 µm diameter electrodes in the presence of microwaves. The electrocatalytic oxidation of glucose at 500 µm diameter Au, Cu, or Ni electrodes immersed in 0.1 M NaOH and in the presence of microwave radiation is shown to be dominated by kinetic control. The magnitude of glucose oxidation currents at Cu electrodes is shown to depend on the thickness of a pre-formed oxide layer. At 50 µm diameter Au, Cu, or Ni electrodes microwave enhanced current densities are generally higher, but only at Au electrodes is a significantly increased rate for the electrocatalytic oxidation of glucose to gluconolactone observed. This rate enhancement appears to be independent of temperature but microwave intensity dependent, and therefore non-thermal in nature. Voltammetric currents observed at Ni electrodes in the presence of microwaves show the best correlation with glucose concentration and are therefore analytically most useful.

Increased versican content is associated with tendinosis pathology in the patellar tendon of athletes with jumper

Expansion of the extracellular matrix is a prominent but poorly characterized feature of tendinosis. The present study aimed to characterize the extent and distribution of the large aggregating proteoglycan versican in patients with patellar tendinosis. We obtained tendon from tendinopathy patients undergoing debridement of the patellar tendon and from controls undergoing intramedullary tibial nailing. Versican content was investigated by Western blotting and immunohistochemistry. Microvessel thickness and density were determined using computer-assisted image analysis. Markers for smooth muscle actin, endothelial cells (CD31) and proliferating cells (Ki67) were examined immunohistochemically. Western blot analysis and immunohistochemical staining revealed elevated versican content in the proximal patellar tendon of tendinosis patients (P=0.042). Versican content was enriched in regions of fibrocartilage metaplasia and fibroblast proliferation, as well as in the perivascular matrix of proliferating microvessels and within the media and intima of arterioles. Microvessel density was higher in tendinosis tissue compared with control tissue. Versican deposition is a prominent feature of patellar tendinosis. Because this molecule is not only a component of normal fibrocartilagenous matrices but also implicated in a variety of soft tissue pathologies, future studies should further detail both pathological and adaptive roles of versican in tendons.

Structure and thickness optimization of active layer in nanoscale organic solar cells

 This paper presents the development of a two-dimensional model of multilayer bulk heterojunction organic nanoscale solar cells, consisting of the thickness of active layer and morphology of the device. The proposed model is utilized to optimize the device parameters in order to achieve the best performance using particle swarm optimization algorithm. The organic solar cells under research are from poly (3-hexylthiophene) and [6,6]-phenyl C61-butyric acid methyl ester type which are modelled to be investigated for performance enhancement. A three-dimensional fitness function is proposed involving domain size and active layer thickness as variables. The best results out of 20 runs of optimization show that the optimized value for domain size is 17 nm, while the short-circuit current vs. voltage characteristic shows a very good agreement with the experimental results obtained by previous researchers. © 2014 Springer Science+Business Media New York

Análise morfométrica digital na parede aórtica de suínos após implante de stents não revestidos versus stents revestidos com dacron

Os stents são dispositivos intravasculares implantados com o objetivo de dilatar ou fixar a placa de colesterol contra a parede arterial. O objetivo avaliar dois tipos de stents de aço inoxidável, um recoberto com poliéster (dacron) e outro não recoberto, implantados na aorta infra-renal de suínos jovens, foram avaliados por morfometria digital para medir o espessamento intimal. Foi realizado um estudo experimental randomizado, separados em dois grupos(stents não revestidos e revestidos com dacron) e duas fases (I e II). Oito stents recobertos com dacron e oito stents de aço inoxidável (30mm de extensão e 8 mm de diâmetro), não revestidos, foram implantados através de abordagem retroperitoneal na aorta infrarenal normal de 16 suínos normolipêmicos. Para a passagem do sistema de implante, foi necessário uma pequena arteriotomia na aorta distal (fase I). Após quatro semanas, a aorta com os stents foram removidas em monoblocos (fase II). Os valores de hematimetria e do lipidograma foram coletados nas duas fases e não apresentaram alterações que pudessem influenciar o estudo. Amostras de tecido dos sítios de fixação (proximal e distal) dos stents foram retiradas, confeccionadas lâminas, que foram coradas pelas técnicas de hematoxilina e eosina de Verhoeff e enviadas para análise morfométrica digital. A camada intima distal não apresentou diferença estatística significativa. A camada média proximal das porções proximal e da porção distal não apresentaram diferença entre os grupos. Os dois tipos de stents apresentaram 100% de perviedade, boa biocompatibilidade e boa incorporação a parede aórtica de suínos normolipêmicos. A camada íntima proximal do grupo de stents revestidos com dacron apresentou espessura maior do que os stents não revestidos, mas com significância estatísitica limítrofe.

Contribution to the study of aortic mural structure of opossum (Didelphis albiventris)

Opossum is considered one of the most primitive mammals, with transition evolutive characteristics. In mammals, the aorta artery is referred as the main body blood vessel. The arteries wall structural organization follows a basic pattern, being contituted of three tunics: Intima, Median and Adventicial. After euthanasia, three samples of opossum had segments from the aorta artery ascendent, thoracic descending and abdominal descending portions removed, fixed in phormalin at 10% for 48 hours. Then, the material was washed in alcohol 70% several times, dehydrated in alcohois of growing concentrations, diafanized in xylol and included in "paraplast". Cuts with 5 to 7 mu m of thickness were placed in histological laminae and submitted to color methods of Hematoxilin-Eosin, Masson, Mallory and Calleja Tricromics. It was observed that in the different portions ascendent, thoracic and abdominal descending of aorta, the intima tunic presents much thick, made up of a layer of smooth muscular cells and elastic fibers, forming a limiting internal elastic membrane. In the three portions studied, the median tunic was the most evident layer, constituted of colagen fibers, smooth muscular cells arranged in a circular manner and elastic fibers, showing a variation in the mural elements proportion. It was evidenced the presence of a external elastic lamina, marking the transition between the median and adventicial tunic, formed by elastic fibers condensation. The aortic adventicial tunic showed to be little organized, having in its structure predominantely colagen fibers beans with some isolated smooth muscular fibers or in small fascicules among a few elastic fibers.

Ultrastructural studies of the mandibular glands of the minima, media and soldier ants of Atta sexdens rubropilosa (Forel 1908)

The mandibular glands of Hymenoptera are structures associated with the mandibles and constitute part of the salivary glands system. Histological studies in workers of Atta sexdens rubropilosa revealed that this gland contains two portions: a secretory and a storage portion or reservoir. Both portions are connected by means of canaliculi. The object of the present work was the study of the ultratructure of the mandibular glands of minima, media and soldier ant of A. s. rubropilosa by TEM techniques. The glands, in the three castes studied, possess a reservoir, constituted by a simple pavementous epithelium surrounded by the cuticular intima and the secretory portion is constituted by cells of rounded shape. The secretory cells, mainly of minima and soldier, were rich in smooth endoplasmic reticulum. The media worker and soldier presented a large number of mitochondria, of varying shape. Well-developed Golgi complexes were also present in the soldiers. The secretory cells in minima, media and soldier were provided with collecting intracellular canaliculi, which were linked to the reservoir through the extracellular portion. The cytoplasm of the canaliculi-forming cell was poor in organelles. In the individuals of the three castes of A. s. rubropilosa, the presence of lipid secretion granules suggested, beyond the other functions, also a possible pheromonal action. The different roles executed by the different insect castes are directly dependent on the glandular products and, consequently, on the secretory cellular characteristics. (c) 2005 Elsevier Ltd. All rights reserved.

Effects of thickness coating on the electrochemical behaviour of thermal spray Cr3C2-NiCr coatings

Thermally sprayed HVOF coatings are increasingly being used in industrial applications where high wear and corrosion resistance are needed [1,2]. In this paper, electrochemical ac and de experiments were used in order to obtain the corrosion resistance of coated steel with different numbers of Cr3C2-NiCr layers. This work has been performed in order to determine the role of coating thickness in the corrosion behaviour of a steel protected with cermet thermally sprayed coatings. It is known that a thicker layer protects better against corrosion when a metallic coating is evaluated. But cermet coatings, such as Cr3C2-NiCr, contain higher levels of porosity and residual stresses than metallic coatings, which really could influence the corrosion resistance of the deposited layer. Electrochemical measurements, such as Open-Circuit Potential (E-Osubset of), Polarisation Resistance (RP) and Cyclic Voltammetry (CV), were performed in an aerated 3.4 NaCI media (%wt.). Electrochemical Impedance Measurements (EIS) were also done in order to obtain a mechanism that explains the corrosion process. Structural Characterisation was carried out by means of Optical and Scanning Electron Microscopes (OM, SEM) with an Energy Dispersive Spectrometry analyser (EDS). Results show that the corrosion resistance of the complete system is mainly influenced by the substrate behaviour. The application of a higher number of deposited layers did not substantially increase their anticorrosive properties. Stress generation during the spraying deposition process plays an important role in the behaviour of the coated steel against corrosion phenomena. (C) 2002 Elsevier B.V. B.V All rights reserved.

Asymmetrical penetration of microwave in a conducting media and determination of microwave conductivity for very thin samples using electron spin resonance

Dyson's theory of conduction electron spin resonance (CESR) has been used in the limit d less than or equal to delta (d being the thickness of the sample and delta the skin depth of the microwave field) to obtain the microwave conductivity from the (A/B) ratio of the CESR absorbed power derivative. In this work we calculate the CESR absorbed power derivative using Kaplan's approach and show that the (A/B) ratio can be enhanced if asymmetrical penetration of microwave is used, which means that the microwave field enters into the sample from one of the faces. Therefore, the determination of the microwave conductivity from the (A/B) ratio of the CESR line can be performed for thinner samples. Experimentally, asymmetrical penetration can be obtained if one of the sample's faces is covered with a thin gold layer. The determination of microwave conductivity in conducting polymers films is among the possible applications of this method. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Estrutura, ultraestrutura e morfometria da aorta de paca (Cuniculus paca, Linnaeus, 1766) criada em cativeiro

The aim of this study was to describe the morphology, morphometry and ultrastructure of segments of thoracic and abdominal aorta portions in four male and female paca (Cuniculus paca). Parts of the segments were examined by light microscopy and part by scanning electron microscopy. Thickness measurements of the tunica intima and media complex and tunica adventitia of the aorta were taken. In all animals the thickness values for the tunica intima and media complex of the cranial thoracic aorta were significantly higher (mean: 702.19 mu m) when compared to the values of other aortic segments analyzed (means: 354.18 mu m; 243.55 mu m). The layers of the vessel walls show variations in structure and thickness, presumably due to an adaptation to functionaldemand.

Effect of finishing and polishing on color stability of a nanofilled resin immersed in different media

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)