Optical, mechanical and surface properties of amorphous carbonaceous thin films obtained by plasma enhanced chemical vapor deposition and plasma immersion ion implantation and deposition

Diverse amorphous hydrogenated carbon-based films (a-C:H, a-C:H:F, a-C:H:N, a-C:H:Cl and a-C:H:Si:O) were obtained by radiofrequency plasma enhanced chemical vapor deposition (PECVD) and plasma immersion ion implantation and deposition (PIIID). The same precursors were used in the production of each pair of each type of film, such as a-C:H, using both PECVD and PIIID. Optical properties, namely the refractive index, n, absorption coefficient, α, and optical gap, ETauc, of these films were obtained via transmission spectra in the ultraviolet-visible near-infrared range (wavelengths from 300 to 3300 nm). Film hardness, elastic modulus and stiffness were obtained as a function of depth using nano-indentation. Surface energy values were calculated from liquid drop contact angle data. Film roughness and morphology were assessed using atomic force microscopy (AFM). The PIIID films were usually thinner and possessed higher refractive indices than the PECVD films. Determined refractive indices are consistent with literature values for similar types of films. Values of ETauc were increased in the PIIID films compared to the PECVD films. An exception was the a-C:H:Si:O films, for which that obtained by PIIID was thicker and exhibited a decreased ETauc. The mechanical properties - hardness, elastic modulus and stiffness - of films produced by PECVD and PIIID generally present small differences. An interesting effect is the increase in the hardness of a-C:H:Cl films from 1.0 to 3.0 GPa when ion implantation is employed. Surface energy correlates well with surface roughness. The implanted films are usually smoother than those obtained by PECVD. ©2013 Elsevier B.V. All rights reserved.

Biocompatibility of Ferrara intracorneal ring segment with and without chondroitin sulfate coating: Clinical and histopathological evaluation in rabbits

PURPOSE: To investigate and compare the biocompatibility of two types of Ferrara intracorneal ring segment: with and without chondroitin sulfate coating by clinical and histopathological evaluation. METHODS: A randomized experimental study was carried out on thirty right-eye corneas from 30 Norfolk albino rabbits allocated into two experimental groups: Group G1 - implanted with Ferrara intracorneal ring segment without coating (FICRS) and Group G2 - implanted with Ferrara intracorneal ring segment with chondroitin sulfate coating (FICRS-CS). Left eyes formed the control group. Clinical parameters analyzed were: presence of edema, vascularization, infection and ring extrusion one, 30, and 60 days after surgery. Histopathological parameters analyzed were: number of corneal epithelial layers over and adjacent to the ring, presence of spongiosis, hydropic degeneration, basement membrane thinning, inflammatory cells, neovascularization and pseudocapsule formation. RESULTS: At clinical examination 60 days after implant, edema, vascularization and extrusion were observed respectively in 20%, 26.7%, 6.7% of FICRS corneas and in 6.7%, 6.7%, and 0% of FICRS-CS corneas. Histopathological evaluation showed epithelial-layer reduction from 5 (5;6) to 3 (3;3) with FICRS and from 5 (5;5) to 4 (3;5) with FICRS-CS in the region over the ring. Epithelial spongiosis, hydropic degeneration, and basement membrane thinning were present in 69.2%, 53.8%, and 69.2% of FICRS and in 73.3%, 73.3%, and 46.7% with FICRS-CS, respectively. Vascularization was present in 38.5% of FICRS and 13.3% with FICRS-CS, inflammatory cells in 75% of FICRS and 33.3% with FICRS-CS, and pseudocapsule in 66.7% of FICRS and 93.3% with FICRS-CS. Giant cells occurred only in the FICRS-CS group (20%). CONCLUSION: Ferrara intracorneal rings coated with chondroitin sulfate (FICRS-CS) caused lower frequency of clinical and histopathological alterations than Ferrara intracorneal rings without the coating (FICRS), demonstrating higher biocompatibility of the FICRS-CS.

Subcutaneous tissue reaction and cytotoxicity of polyvinylidene fluoride and polyvinylidene fluoride-trifluoroethylene blends associated with natural polymers

Cytotoxicity and subcutaneous tissue reaction of innovative blends composed by polyvinylidene fluoride and polyvinylidene fluoride-trifluoroethylene associated with natural polymers (natural rubber and native starch) forming membranes were evaluated, aiming its applications associated with bone regeneration. Cytotoxicity was evaluated in mouse fibroblasts culture cells (NIH3T3) using trypan blue staining. Tissue response was in vivo evaluated by subcutaneous implantation of materials in rats, taking into account the presence of necrosis and connective tissue capsule around implanted materials after 7, 14, 21, 28, 35, 60, and 100 days of surgery. The pattern of inflammation was evaluated by histomorphometry of the inflammatory cells. Chemical and morphological changes of implanted materials after 60 and 100 days were evaluated by Fourier transform infrared (FTIR) absorption spectroscopy and scanning electron microscopy (SEM) images. Cytotoxicity tests indicated a good tolerance of the cells to the biomaterial. The in vivo tissue response of all studied materials showed normal inflammatory pattern, characterized by a reduction of polymorphonuclear leukocytes and an increase in mononuclear leukocytes over the time (p < 0.05 Kruskal-Wallis). On day 60, microscopic analysis showed regression of the chronic inflammatory process around all materials. FTIR showed no changes in chemical composition of materials due to implantation, whereas SEM demonstrated the delivery of starch in the medium. Therefore, the results of the tests performed in vitro and in vivo show that the innovative blends can further be used as biomaterials. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 101B: 1284-1293, 2013. Copyright © 2013 Wiley Periodicals, Inc.

Commissural nucleus of the solitary tract regulates the antihypertensive effects elicited by moxonidine

The rostral ventrolateral medulla (RVLM) contains the presympathetic neurons involved in cardiovascular regulation that has been implicated as one of the most important central sites for the antihypertensive action of moxonidine (an α2-adrenergic and imidazoline agonist). Here, we sought to evaluate the cardiovascular effects produced by moxonidine injected into another important brainstem site, the commissural nucleus of the solitary tract (commNTS). Mean arterial pressure (MAP), heart rate (HR), splanchnic sympathetic nerve activity (sSNA) and activity of putative sympathoexcitatory vasomotor neurons of the RVLM were recorded in conscious or urethane-anesthetized, and artificial ventilated male Wistar rats. In conscious or anesthetized rats, moxonidine (2.5 and 5. nmol/50. nl) injected into the commNTS reduced MAP, HR and sSNA. The injection of moxonidine into the commNTS also elicited a reduction of 28% in the activity of sympathoexcitatory vasomotor neurons of the RVLM. To further assess the notion that moxonidine could act in another brainstem area to elicit the antihypertensive effects, a group with electrolytic lesions of the commNTS or sham and with stainless steel guide-cannulas implanted into the 4th V were used. In the sham group, moxonidine (20. nmol/1. μl) injected into 4th V decreased MAP and HR. The hypotension but not the bradycardia produced by moxonidine into the 4th V was reduced in acute (1. day) commNTS-lesioned rats. These data suggest that moxonidine can certainly act in other brainstem regions, such as commNTS to produce its beneficial therapeutic effects, such as hypotension and reduction in sympathetic nerve activity. © 2013 IBRO.

Facilitation of sodium intake by combining noradrenaline into the lateral parabrachial nucleus with prazosin peripherally

Injections of noradrenaline into the lateral parabrachial nucleus (LPBN) increase arterial pressure and 1.8% NaCl intake and decrease water intake in rats treated with the diuretic furosemide (FURO) combined with a low dose of the angiotensin converting enzyme inhibitor captopril (CAP). In the present study, we investigated the influence of the pressor response elicited by noradrenaline injected into the LPBN on FURO + CAP-induced water and 1.8% NaCl intake. Male Holtzman rats with bilateral stainless steel guide-cannulas implanted into LPBN were used. Bilateral injections of noradrenaline (40 nmol/0.2 μl) into the LPBN increased FURO + CAP-induced 1.8% NaCl intake (12.2 ± 3.5, vs., saline: 4.2 ± 0.8 ml/180 min), reduced water intake and strongly increased arterial pressure (50 ± 7, vs. saline: 1 ± 1 mm Hg). The blockade of the α1 adrenoceptors with the prazosin injected intraperitoneally abolished the pressor response and increased 1.8% NaCl and water intake in rats treated with FURO + CAP combined with noradrenaline injected into the LPBN. The deactivation of baro and perhaps volume receptors due to the cardiovascular effects of prazosin is a mechanism that may facilitate water and NaCl intake in rats treated with FURO + CAP combined with noradrenaline injected into the LPBN. Therefore, the activation of α2 adrenoceptors with noradrenaline injected into the LPBN, at least in dose tested, may not completely remove the inhibitory signals produced by the activation of the cardiovascular receptors, particularly the signals that result from the extra activation of these receptors with the increase of arterial pressure. © 2013 Elsevier Inc.

Tribocorrosion behaviour of anodic treated titanium surfaces intended for dental implants

Tribocorrosion plays an important role in the lifetime of metallic implants. Once implanted, biomaterials are subjected to micro-movements in aggressive biological fluids. Titanium is widely used as an implant material because it spontaneously forms a compact and protective nanometric thick oxide layer, mainly TiO2, in ambient air. That layer provides good corrosion resistance, and very low toxicity, but its low wear resistance is a concern. In this work, an anodizing treatment was performed on commercial pure titanium to form a homogeneous thick oxide surface layer in order to provide bioactivity and improve the biological, chemical and mechanical properties. Anodizing was performed in an electrolyte containing β-glycerophosphate and calcium acetate. The influence of the calcium acetate content on the tribocorrosion behaviour of the anodized material was studied. The concentration of calcium acetate in the electrolyte was found to largely affect the crystallographic structure of the resulting oxide layer. Better tribocorrosion behaviour was noticed on increasing the calcium acetate concentration. © 2013 IOP Publishing Ltd.

Would right atrial stretch inhibit sodium intake following GABAA receptor activation in the lateral parabrachial nucleus?

The knowledge of the mechanisms underlying circulating volume control may be achieved by stretching a balloon placed at the junction of the superior vena cava-right atrial junction (SVC-RAJ). We investigated whether the inflation of a balloon at the SVC-RAJ inhibits the intake of 0.3M NaCl induced by GABAA receptor activation in the lateral parabrachial nucleus (LPBN) in euhydrated and satiated rats. Male Wistar rats (280-300g) with bilateral stainless steel LPBN cannulae and balloons implanted at the SVC-RAJ were used. Bilateral injections of the GABAA receptor agonist muscimol (0.5ηmol/0.2l) in the LPBN with deflated balloons increased intake of 0.3M NaCl (30.1±3.9 vs. saline: 2.2±0.7)ml/210min, n=8) and water (17.7±1.9 vs. saline: 2.9±0.5ml/210min). Conversely, 0.3M NaCl (27.8±2.1ml/210min) and water (22.8±2.3ml/210min) intake were not affected in rats with inflated balloons at the SVC-RAJ. The results show that sodium and water intake induced by muscimol injected into the LPBN was not affected by balloon inflation at the SVC-RAJ. We suggest that the blockade of LPBN neuronal activity with muscimol injections impairs inhibitory mechanisms activated by signals from cardiopulmonary volume receptors determined by balloon inflation. © 2013 The Authors.

O uso de implantes orbitários no reparo de cavidades anoftálmicas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Correlação e análise de trilha de produtividade de grãos e seus componentes e caracteres de planta em cártamo (Carthamus tinctorius L.) e mamona (Ricinus communis L.)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Reconhecimento de palavras, nomeação de figuras e de palavras impressas em surdos implantados pré-linguais

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

Suplementação alimentar com ácidos graxos essenciais para tilápias do Nilo: desempenho produtivo, hematológico e granuloma por corpo estranho

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Acurácia na determinação das coordenadas dos vértices de imóveis urbanos

Pós-graduação em Ciências Cartográficas - FCT

Caminhos da cerâmica em Cunha: paneleiras, olarias e ateliês, elementos importantes na formação do histórico ceramista da cidade

Pós-graduação em Artes - IA

Validação de recursos de cargas viral do HIV-1 obtidos para insumos/kids/equipamentos de diferentes procedênias

Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB

Influência de fragmentos de cerrado vizinhos à seringal (Hevea brasiliensis Muell. Arg.) na distribuição e infecção fúngica de ácaros (Acari, Arachnida)

Pós-graduação em Biologia Animal - IBILCE