8 research outputs found
Managing human stress level. A multimedia sequence approach
No full textPrevious literature studies demonstrated that affect can be positively or negatively influenced by single images, sounds and videos. In this study it has been investigated the effect of a software named 2VitaB-Cognitive on people stress: this software generates a multimedia sequence composed of positive images, sounds and video that can be presented on a PC, tablet, or smartphone. An experimental activity has been performed to verify the impact of the stimulation with the multimedia sequence on both affect and vigilance of 10 volunteers. Participants stress level was assessed using the PSS-10; they also filled in some scales and questionnaires (PANAS, SAM and GVAS) and completed the PVT vigilance task both before and after the administration of the multimedia sequence. The effect of the stimulation on affect and vigilance has been defined comparing answers to questionnaires and task results before and after the administration of the multimedia sequence. Results indicated that the multimedia stimulation can produce a modification on human affect and vigilance
Ship control system wide integration and the use of dynamic simulation techniques in the Fremm project
No full textShip control system wide integration and the use of dynamic simulation techniques in the Fremm project
No full textNitric Oxide-releasing Poly(vinyl Alcohol) Film For Increasing Dermal Vasodilation
No full textPathological conditions associated with the impairment of nitric oxide (NO) production in the vasculature, such as Raynaud's syndrome and diabetic angiopathy, have stimulated the development of new biomaterials capable of delivering NO topically. With this purpose, we modified poly(vinyl-alcohol) (PVA) by chemically crosslinking it via esterification with mercaptosuccinic acid. This reaction allowed the casting of sulfhydrylated PVA (PVA-SH) films. Differential scanning calorimetry and X-ray diffractometry showed that the crosslinking reaction completely suppressed the crystallization of PVA, leading to a non-porous film with a homogeneous distribution of -SH groups. The remaining free hydroxyl groups in the PVA-SH network conferred partial hydrophylicity to the material, which was responsible for a swelling degree of ca. 110%. The PVA-SH films were subjected to an S-nitrosation reaction of the -SH groups, yielding a PVA containing S-nitrosothiol groups (PVA-SNO). Amperometric and chemiluminescence measurements showed that the PVA-SNO films were capable of releasing NO spontaneously after immersion in physiological medium. Laser Doppler-flowmetry, used to assess the blood flow in the dermal microcirculation, showed that the topical application of hydrated PVA-SNO films on the health skin led to a dose- and time-dependent increase of more than 5-fold in the dermal baseline blood flow in less than 10. min, with a prolonged action of more than 4. h during continuous application. These results show that PVA-SNO films might emerge as a new material with potential for the topical treatment of microvascular skin disorders. © 2013 Elsevier B.V.116643651Holowatz, L.A., Thompson-Torgerson, C.S., Kenney, W.L., The human cutaneous circulation as a model of generalized microvascular function (2008) J. Appl. Physiol., 105, pp. 370-372Seabra, A.B., Fitzpatrick, A., Paul, J., de Oliveira, M.G., Weller, R., Topically applied S-nitrosothiol-containing hydrogels as experimental and pharmacological nitric oxide donors in human skin (2004) Br. J. Dermatol., 151, pp. 977-983Turton, E., Vascular review: the aetiology of Raynaud's phenomenon (1998) Cardiovasc. Surg., 6, pp. 431-440Tucker, A.T., Pearson, R.M., Cooke, E.D., Benjamin, N., Effect of nitric-oxide-generating system on microcirculatory blood flow in skin of patients with severe Raynaud's syndrome: a randomised trial (1999) Lancet, 354, pp. 1670-1675Moncada, S., Radomski, M.W., Palmer, R.M., Endothelium-derived relaxing factor Identification as nitric oxide and role in the control of vascular tone and platelet function (1988) Biochem. Pharmacol., 37, pp. 2495-2501Amadeu, T.P., Seabra, A.B., de Oliveira, M.G., Monte-Alto-Costa, A., Nitric oxide donor improves healing if applied on inflammatory and proliferative phase (2008) J. Surg. Res., 149, pp. 84-93Kopeček, J., Yang, J., Hydrogels as smart biomaterials (2007) Polym. Int., 56, pp. 1078-1098Seabra, A.B., Pankotai, E., Fehér, M., Somlai, L., Kiss, L., Bíró, C., Szabó, M., de Oliveira, Z., Lacza, S-nitrosoglutathione-containing hydrogel increases dermal blood flow in streptozotocin-induced diabetic rats (2007) Br. J. Dermatol., 156, pp. 814-818Amadeu, T.P., Seabra, A.B., de Oliveira, M.G., Costa, A.M.A., S-nitrosoglutathione-containing hydrogel accelerates rat cutaneous wound repair, (2007) J. Eur. Acad. Dermatol. Venereol., 21, pp. 629-637Georgii, J.L., Amadeu, T.P., Seabra, A.B., de Oliveira, M.G., Monte-Alto-Costa, A., Topical S-nitrosoglutathione-releasing hydrogel improves healing of rat ischaemic wounds (2011) J. Tissue Eng. Regen. Med., 5, pp. 612-619Vercelino, R., Cunha, T.M., Ferreira, E.S., Cunha, F.Q., Ferreira, S.H., de Oliveira, M.G., Skin vasodilation and analgesic effect of a topical nitric oxide-releasing hydrogel (2013) J. Mater. Sci. Mater. Med.Frost, M.C., Reynolds, M.M., Meyerhoff, M.E., Polymers incorporating nitric oxide releasing/generating substances for improved biocompatibility of blood-contacting medical devices (2005) Biomaterials, 26, pp. 1685-1693Damodaran, V.B., Joslin, J.M., Wold, K.A., Lantvit, S.M., Reynolds, M.M., S-Nitrosated biodegradable polymers for biomedical applications: synthesis, characterization and impact of thiol structure on the physicochemical properties (2012) J. Mater. Chem., 22, p. 5990Simões, M.M.D., Oliveira, M.G., Poly(vinyl alcohol) films for topical delivery of S-nitrosoglutathione: effect of freezing-thawing on the diffusion properties, (2010) J. Biomed. Mater. Res. Part B: Appl. Biomater., 93, pp. 416-424DeMerlis, C.C., Schoneker, D.R., Review of the oral toxicity of polyvinyl alcohol (PVA) (2003) Food Chem. Toxicol., 41, pp. 319-326Jipa, I.M., Stroescu, M., Stoica-Guzun, A., Dobre, T., Jinga, S., Zaharescu, T., Effect of gamma irradiation on biopolymer composite films of poly(vinyl alcohol) and bacterial cellulose (2012) Nucl. Instrum. Methods Phys. Res., Sect. B, 278, pp. 82-87Moritani, T., Okaya, T., Functional modification of poly(vinyl alcohol) by copolymerization: IV self-crosslinkable poly(vinyl alcohol)s (1998) Polymer, 39, pp. 923-931Hasimi, A., Stavropoulou, A., Papadokostaki, K.G., Sanopoulou, M., Transport of water in polyvinyl alcohol films: effect of thermal treatment and chemical crosslinking (2008) Eur. Polym. J., 44, pp. 4098-4107Chetri, P., Dass, N.N., Sen Sarma, N., Synthesis of poly(vinyl propionate) from poly(vinyl alcohol) in nonaqueous medium using ethyl nitrate dimethyl sulfoxide as a catalyst (2006) J. Appl. Polym. Sci., 102, pp. 5675-5679Kim, D., Park, H., Rhim, J., Lee, Y., Proton conductivity and methanol transport behavior of cross-linked PVA/PAA/silica hybrid membranes (2005) Solid State Ionics, 176, pp. 117-126Gomez, M., Domingo, J.L., Llobet, J.M., Corbella, J., Evaluation of the efficacy of various chelating agents on urinary excretion and tissue distribution of vanadium in rats (1991) Toxicol. Lett., 57, pp. 227-234Arnold, A.P., Canty, A.J., Moors, P.W., Deacon, G.B., Chelation therapy for methylmercury(II) poisoning synthesis and determination of solubility properties of MeHg(II) complexes of thiol and dithiol antidotes (1983) J. Inorg. Biochem., 19, pp. 319-327Maiorino, R.M., Aposhian, H.V., Determination and metabolism of dithiol chelating agents (1989) Biochem. Pharmacol., 38, pp. 1147-1154Prudente, A., Riccetto, C.L.Z., Simões, M.M.D., Pires, B.M., Oliveira, M.G., Impregnation of implantable polypropylene mesh with S-nitrosoglutathione-loaded poly(vinyl alcohol), (2013) Colloids Surf., B, 108 C, pp. 178-184Nagababu, E., Rifkind, J.M., Measurement of plasma nitrite by chemiluminescence (2010) Methods Mol. Biol., 610, pp. 41-49Yang, F., Troncy, E., Francoeur, M., Vinet, B., Vinay, P., Czaika, G., Blaise, G., Effects of reducing reagents and temperature on conversion of nitrite and nitrate to nitric oxide and detection of NO by chemiluminescence (1997) Clin. Chem., 43, pp. 657-662Zekarias, M.T., Rao, G.N., Evaluation of protonation constants of mercaptosuccinic acid in aqueous solutions of propylene glycol and dioxan (2012) J. Chilean Chem. Soc., 57, pp. 1054-1057Pavia, D.L., Lampman, G.M., Kriz, G.S., Vyvyan, J.R., (2009) Introduction to Spectroscopy, , Cengage Learning, Belmont, CA, USAAssendert, H.E., Windle, A.H., Crystallinity in poly(vinyl alcohol) 1. An X-ray diffraction study of atactic PVOH (1998) Polymer, 39, pp. 4295-4302Mateescu, M.A., Schell, H.D., Dimonie, M., Todireanu, S., Maior, O., Some peculiar properties of cross-linked polyvinyl alcohol (CL-PVA) related to the reticulation degree (1984) Polym. Bull., 11, pp. 421-427Peppas, N.A., Khare, A.R., Preparation, structure and diffusional behavior of hydrogels in controlled release (1993) Adv. Drug Deliv. Rev., 11, pp. 1-35Omidian, H., Park, K., Swelling agents and devices in oral drug delivery (2008) J. Drug Deliv. Sci. Technol., 18, pp. 83-93Geise, G.M., Paul, D.R., Freeman, B.D., Fundamental water and salt transport properties of polymeric materials (2013) Prog. Polym. Sci., pp. 1-42de Oliveira, M.G., Shishido, M., Seabra, A.B., Morgon, N.H., Thermal stability of primary S-nitrosothiols: roles of autocatalysis and structural effects on the rate of nitric oxide release (2002) J. Phys. Chem. A, pp. 8963-8970Seabra, A.B., Martins, D., Simões, M.M.S.G., Silva, R., Brocchi, M., de Oliveira, M.G., Antibacterial nitric oxide-releasing polyester for the coating of blood-contacting artificial materials (2010) Artif. Organs, 34, pp. 204-214Nilsson, G.E., Tenland, T., Oberg, P.A., Evaluation of a laser Doppler flowmeter for measurement of tissue blood flow (1980) IEEE Trans. Biomed. Eng., 27, pp. 597-60
Nitric oxide-releasing poly(vinyl alcohol) film for increasing dermal vasodilation
No full textConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Pathological conditions associated with the impairment of nitric oxide (NO) production in the vasculature, such as Raynaud's syndrome and diabetic angiopathy, have stimulated the development of new biomaterials capable of delivering NO topically. With this purpose, we modified poly(vinyl-alcohol) (PVA) by chemically crosslinking it via esterification with mercaptosuccinic acid. This reaction allowed the casting of sulfhydrylated PVA (PVA-SH) films. Differential scanning calorimetry and X-ray diffractometry showed that the crosslinking reaction completely suppressed the crystallization of PVA, leading to a non-porous film with a homogeneous distribution of -SH groups. The remaining free hydroxyl groups in the PVA-SH network conferred partial hydrophylicity to the material, which was responsible for a swelling degree of ca. 110%. The PVA-SH films were subjected to an S-nitrosation reaction of the -SH groups, yielding a PVA containing S-nitrosothiol groups (PVA-SNO). Amperometric and chemiluminescence measurements showed that the PVA-SNO films were capable of releasing NO spontaneously after immersion in physiological medium. Laser Doppler-flowmetry, used to assess the blood flow in the dermal microcirculation, showed that the topical application of hydrated PVA-SNO films on the health skin led to a dose- and time-dependent increase of more than 5-fold in the dermal baseline blood flow in less than 10 min, with a prolonged action of more than 4 h during continuous application. These results show that PVA-SNO films might emerge as a new material with potential for the topical treatment of microvascular skin disorders. (C) 2013 Elsevier B.V. All rights reserved.116643651Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CNPq [309390/2011-7]FAPESP [2008/57560-0
Nitric oxide-releasing poly(vinyl alcohol) film for increasing dermal vasodilation
No full textPathological conditions associated with the impairment of nitric oxide (NO) production in the vasculature, such as Raynaud's syndrome and diabetic angiopathy, have stimulated the development of new biomaterials capable of delivering NO topically. With this purpose, we modified poly(vinyl-alcohol) (PVA) by chemically crosslinking it via esterification with mercaptosuccinic acid. This reaction allowed the casting of sulfhydrylated PVA (PVA-SH) films. Differential scanning calorimetry and X-ray diffractometry showed that the crosslinking reaction completely suppressed the crystallization of PVA, leading to a non-porous film with a homogeneous distribution of -SH groups. The remaining free hydroxyl groups in the PVA-SH network conferred partial hydrophylicity to the material, which was responsible for a swelling degree of ca. 110%. The PVA-SH films were subjected to an S-nitrosation reaction of the -SH groups, yielding a PVA containing S-nitrosothiol groups (PVA-SNO). Amperometric and chemiluminescence measurements showed that the PVA-SNO films were capable of releasing NO spontaneously after immersion in physiological medium. Laser Doppler-flowmetry, used to assess the blood flow in the dermal microcirculation, showed that the topical application of hydrated PVA-SNO films on the health skin led to a dose- and time-dependent increase of more than 5-fold in the dermal baseline blood flow in less than 10 min, with a prolonged action of more than 4 h during continuous application. These results show that PVA-SNO films might emerge as a new material with potential for the topical treatment of microvascular skin disorders116643651CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP309390/2011-72008/57560-
Eco-Friendly Colloidal Aqueous Sol-Gel Process for TiO2 Synthesis: The Peptization Method to Obtain Crystalline and Photoactive Materials at Low Temperature
No full textpeer reviewedThis work reviews an eco-friendly process for producing TiO2 via colloidal aqueous sol–gel synthesis, resulting in crystalline materials without a calcination step. Three types of colloidal aqueous TiO2 are reviewed: the as-synthesized type obtained directly after synthesis, without any specific treatment; the calcined, obtained after a subsequent calcination step; and the hydrothermal, obtained after a specific autoclave treatment. This eco-friendly process is based on the hydrolysis of a Ti precursor in excess of water, followed by the peptization of the precipitated TiO2. Compared to classical TiO2 synthesis, this method results in crystalline TiO2 nanoparticles without any thermal treatment and uses only small amounts of organic chemicals. Depending on the synthesis parameters, the three crystalline phases of TiO2 (anatase, brookite, and rutile) can be obtained. The morphology of the nanoparticles can also be tailored by the synthesis parameters. The most important parameter is the peptizing agent. Indeed, depending on its acidic or basic character and also on its amount, it can modulate the crystallinity and morphology of TiO2. Colloidal aqueous TiO2 photocatalysts are mainly being used in various photocatalytic reactions for organic pollutant degradation.
The as-synthesized materials seem to have equivalent photocatalytic efficiency to the photocatalysts post-treated with thermal treatments and the commercial Evonik Aeroxide P25, which is produced by a high-temperature process. Indeed, as-prepared, the TiO2 photocatalysts present a high specific surface area and crystalline phases. Emerging applications are also referenced, such as elaborating catalysts for fuel cells, nanocomposite drug delivery systems, or the inkjet printing of microstructures. Only a few works have explored these new properties, giving a lot of potential avenues for studying this eco-friendly TiO2 synthesis method for innovative implementations
Crystalline ZnO Photocatalysts Prepared at Ambient Temperature: Influence of Morphology on p-Nitrophenol Degradation in Water
No full textpeer reviewedSince the Industrial Revolution, technological advances have generated enormous emissions
of various pollutants affecting all ecosystems. The detection and degradation of pollutants has
therefore become a critical issue. More than 59 different remediation technologies have already been developed, such as biological remediation, and physicochemical and electrochemical methods. Among these techniques, advanced oxidation processes (AOPs) have been popularized in the treatment of wastewater. The use of ZnO as a photocatalyst for water remediation has been developing fast in recent years. In this work, the goals are to produce ZnO photocatalysts with different morphologies, by using a green sol-gel process, and to study both the influence of the synthesis parameters on the resulting morphology, and the influence of these different morphologies on the photocatalytic activity, for the degradation of an organic pollutant in water. Multiple morphologies were produced (nanotubes, nanorods, nanospheres), with the same crystalline phase (wurtzite). The most important parameter controlling the shape and size was found to be pH. The photoactivity study on a model of pollutant degradation shows that the resulting activity is mainly governed by the specific surface area of the material. A comparison with a commercial TiO2 photocatalyst (Evonik P25) showed that the best ZnO produced with this green process can reach similar photoactivity without a calcination step
