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1.
Luminescence ; 39(5): e4753, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38698700

RESUMO

A simple and environmentally friendly method was developed for smart and efficient waterborne polyurethane (PUR) paint. Sugarcane bagasse was recycled into reduced graphene oxide nanosheets (rGONSs). Both lanthanide-doped aluminate nanoparticles (LAN; photoluminescent agent, 7-9 nm) and rGONSs (reinforcement agent) were integrated into a waterborne polyurethane to produce a novel photoluminescent, hydrophobic, and anticorrosive nanocomposite coating. Using ferrocene-based oxidation under masked circumstances, graphene oxide nanosheets were produced from sugarcane bagasse. The oxidized semicarbazide (SCB) nanostructures were integrated into polyurethane coatings as a drying, anticorrosion, and crosslinking agent. Polyurethane coatings with varying amounts of phosphor pigment were prepared and subsequently applied to mild steel. The produced paints (LAN/rGONSs@PUR) were tested for their hydrophobicity, hardness, and scratch resistance. Commission Internationale de l'éclairage (CIE) Laboratory parameters and photoluminescence analysis established the opacity and colourimetric properties of the nanocomposite coatings. When excited at 365 nm, the luminescent transparent paints emitted a strong greenish light at 517 nm. The anticorrosion characteristics of the coated steel were investigated. The phosphor-containing (11% w/w) polyurethane coatings displayed the most pronounced anticorrosion capability and long-persistent luminosity. The prepared waterborne polyurethane paints were very photostable and durable.


Assuntos
Grafite , Interações Hidrofóbicas e Hidrofílicas , Nanocompostos , Pintura , Poliuretanos , Poliuretanos/química , Grafite/química , Nanocompostos/química , Luminescência , Corrosão , Química Verde
2.
Am J Dent ; 36(4): 193-200, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37587030

RESUMO

PURPOSE: To evaluate the effect of different varnishes on dentin permeability to erosive/abrasive challenges. METHODS: 60 superficial dentin discs were randomly allocated to six groups (n=10): Duraphat, PRG Barrier Coat, Clinpro XT, Profluorid, Fluor Protector S and untreated (control). Permeability tests were carried out: after acid conditioning, after treatment, and after abrasive/erosive challenges. The abrasive-erosive challenges were performed for 5 days (citric acid and in remineralizing saliva), as well as abrasion with toothpaste slurry (Colgate Total 12). Scanning electron microscopy (SEM) images were obtained of the dentin surfaces (5,000x) after the treatments, and after the erosive/abrasive challenges. RESULTS: Kruskal-Wallis and Dunn tests showed that all the varnishes promoted a decrease in dentin permeability directly after application, with Clinpro XT showing the highest percentage (69.52%) of dentin sealing (P= 0.0188). After the erosive/abrasive challenge, only PRG Barrier Coat varnish showed dentin sealing ability with reduced dentin permeability (42.16%) (P= 0.0014). However, none of the applied varnishes promoted a statistically significant difference in the percentage of dentin sealing, compared with the control group (P> 0.05). Clinpro XT showed a higher percentage of dentin sealing, while only PRG Barrier Coat showed reduced dentin permeability after the erosive/abrasive challenge. CLINICAL SIGNIFICANCE: Varnish containing S-PRG filler has the efficacy needed to be used as a coating material to reduce dentin permeability in situations of erosive/abrasive challenges.


Assuntos
Ácido Cítrico , Permeabilidade da Dentina , Pintura , Microscopia Eletrônica de Varredura , Saliva , Cremes Dentais , Dentina
3.
Ecotoxicol Environ Saf ; 242: 113877, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35849903

RESUMO

Microplastic particles (MP) and nanoplastic particles (NP) as persistent anthropogenic pollutants may impact environmental and human health. A relevant potential source of primary MP and NP is water-based dispersion paint which are commonly used in any household. Given the worldwide high application volume of dispersion paint and their diverse material composition MP and NP may enter the environment with unforeseeable consequences. In order to understand the relevance of these MP and NP from paint dispersion we investigated the components of two representative wall paints and analyzed their composition in detail. The different paint components were then investigated for their impact on the model organism Daphnia magna and on a murine cell line. Plastic NP, dissolved polymers, titanium dioxide NPs, and calcium carbonate MPs demonstrated adverse effects in both biological test systems, indicating detrimental consequences of several typical components of wall paints upon release into the environment. The outcome of this study may form the basis for the evaluation of impact on other organisms, environmental transport and impact, other related technical materials and for the development of strategies for the prevention of potential detrimental effects on organisms.


Assuntos
Microplásticos , Poluentes Químicos da Água , Animais , Daphnia , Humanos , Camundongos , Pintura/toxicidade , Plásticos/toxicidade , Polímeros , Poluentes Químicos da Água/análise
4.
Environ Sci Technol ; 55(13): 9255-9265, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34101438

RESUMO

This work reports the incorporation of mixed-metal oxides (MMOs) such as Si/Ti and Si/Zr into latex paints in the form of thin coatings for permanent trapping of indoor formaldehyde. The formaldehyde removal performance of the surface coatings was evaluated in a lab-scale indoor air chamber, and the results were compared with those of powder analogues. Due to the pore blockage by the latex, the incorporation led to 6-30% reduction in adsorption capacity and 50-70% drop in the adsorption rate for MMO-latex paints relative to their powder MMO analogues. Under the operating conditions of concentration, temperature, and relative humidity, the Si/Zr-latex paints outperformed the Si/Ti counterparts. It was also observed that performance could decrease over excessive loading, for example, Si/Zr-latex paint with 15/1 Si/Zr weight ratio showed a 20% lower adsorption capacity than that of the Si/Zr-latex paint with 25/1 Si/Zr ratio at 5 ppmv, 25 °C, and 70% RH. While high temperature greatly reduced the adsorption rate of the MMO-latex paints, high humidity slightly promoted the rate of formaldehyde capture. In 10 L, flow-through chamber tests, 25Si/Zr-latex paint reduced 5 ppmv formaldehyde by up to 60% at 25 °C and 70% RH with an adsorption rate of 0.34 ppmv/h. Overall, this study highlights the potential of MMO-latex paints with optimized formation for the efficient abatement of indoor aldehydes.


Assuntos
Poluição do Ar em Ambientes Fechados , Látex , Poluição do Ar em Ambientes Fechados/análise , Formaldeído/análise , Óxidos , Pintura
5.
Macromol Rapid Commun ; 42(10): e2100008, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33851464

RESUMO

A novel method is demonstrated to encapsulate titanium dioxide pigment using directed polymerization-induced self-assembly (PISA) with reversible addition-fragmentation chain-transfer (RAFT) controlled emulsion polymerization. The polymerization is carried out in a batch process in which both styrene (Sty) and the pigment are emulsified using triblock amphiphilic macro-RAFT copolymers as stabilizers. RAFT-controlled chain growth leads to directed lamellar self-assembly, forming polystyrene (PS) shells' encapsulating pigment particles with 100% efficiency. The pigment resides either at centers of single-void vesicles or within the interior of multivoid vesiculated particles. The presence of complex morphologies such as spherical particles, nanofibers, nanoplatelets, and polymer vesicles confirms the PISA pathway. The process is optimized to preferably produce polymer-vesiculated pigment for use as an enhanced opacifier in water-based paint.


Assuntos
Polímeros , Poliestirenos , Emulsões , Pintura , Polimerização
6.
Inhal Toxicol ; 33(2): 55-65, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33622153

RESUMO

PURPOSE: Limited number of studies investigated the effects of Electrostatic powder paints (EPP) on human health. We investigated the effects of EPP exposure on lung function, exercise capacity, and quality of life, and the factors determining exercise capacity in EPP workers. METHODS: Fifty-four male EPP workers and 54 age-matched healthy male individuals (control group) were included. Lung function and respiratory muscle strength were measured. The lower limit of normal (LLN) cut-points for FEV1 and FEV1/FVC were calculated. An EPT was used to evaluate bronchial hyperactivity. The handgrip and quadriceps muscle strength were evaluated using a hand-held dynamometer. An ISWT was used to determine exercise capacity. The physical activity level was questioned using the IPAQ. The SGRQ and NHP were used to assessing respiratory specific and general quality of life, respectively. RESULTS: Duration of work, FEV1, MIP, handgrip strength, and ISWT distance were significantly lower, and the change in FEV1 after EPT and %HRmax were significantly higher in the EPP group compared to the control group (p < 0.05). There were no subjects with a < LLN for FEV1 and FEV1/FVC in both groups. In the EPP group, ISWT distance was significantly related to age, height, duration of work, FEV1, change in FEV1 after EPT, MIP, MEP, handgrip strength, IPAQ, SGRQ, and NHP total scores (p < 0.05). The change in FEV1 after EPT, MIP, and duration of work explained % 62 of the variance in the ISWT distance (p < 0.001). CONCLUSIONS: Changes in lung function based on LLN for the FEV1 and FEV1/FVC were not clinically relevant in EPP workers. Exercise capacity is impaired in EPP workers. Degree of exercise-induced bronchospasm, inspiratory muscle strength, and duration of work are the determinants of exercise capacity in EPP workers.


Assuntos
Tolerância ao Exercício/efeitos dos fármacos , Exposição Ocupacional , Pintura/análise , Poliésteres/toxicidade , Pós/toxicidade , Músculos Respiratórios/efeitos dos fármacos , Adulto , Estudos de Casos e Controles , Humanos , Masculino , Força Muscular/efeitos dos fármacos , Pintura/efeitos adversos , Poliésteres/administração & dosagem , Poliésteres/análise , Pós/administração & dosagem , Pós/efeitos adversos , Testes de Função Respiratória , Caminhada , Adulto Jovem
7.
Contact Dermatitis ; 85(5): 494-502, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34260080

RESUMO

INTRODUCTION: Painters and varnishers ("painters") are exposed to various contact allergens and skin irritants, and therefore, are at risk for developing occupational dermatitis (OD). OBJECTIVE: To describe the spectrum of occupational sensitizations in painters and revise the corresponding current patch test recommendations. PATIENTS AND METHODS: Retrospective analysis of Information Network of Departments of Dermatology (IVDK) data from 2000 to 2019 with focus on male painters with OD, ages 20-59 years (n = 557) in comparison to age-matched male painters without OD (n = 422) and male OD patients who have had never worked as painters (n = 13 862). RESULTS: Male painters with OD have a significantly higher rate of allergic contact dermatitis and face dermatitis than male patients with OD who work in other professions. Positive patch tests to epoxy resin, methylisothiazolinone (MI), and methylchloroisothiazolinone (MCI)/MI were significantly more frequent in painters with OD than in the other groups. Epoxy resin sensitization was significantly associated with face dermatitis. CONCLUSIONS: Epoxy resin, MI, and MCI/MI represent the most important occupational sensitizers in painters. In addition to baseline, resins and glues, and industrial biocides series, the patients' own workplace materials should be tested in painters with suspected OD.


Assuntos
Dermatite Alérgica de Contato/epidemiologia , Dermatite Ocupacional/epidemiologia , Eczema/epidemiologia , Resinas Epóxi/efeitos adversos , Dermatoses da Mão/epidemiologia , Pintura/efeitos adversos , Adulto , Alérgenos/efeitos adversos , Dermatite Alérgica de Contato/diagnóstico , Dermatite Ocupacional/diagnóstico , Eczema/induzido quimicamente , Alemanha , Dermatoses da Mão/induzido quimicamente , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
8.
Contact Dermatitis ; 84(4): 240-246, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33184864

RESUMO

BACKGROUND: Contact allergy from acrylic compounds is a "hot topic". Knowledge on the exact chemical composition of acrylic products is superficial. AIMS: To retrospectively describe patients with allergic reactions to acrylic compounds. METHODS: We included patients who had been tested with acrylate patch test series and displayed allergic reactions to at least one acrylic compound. Chemical analyses were often performed when safety data sheets of implicated products failed to reveal acrylic compounds to which the patient tested positive. RESULTS: In 2010-2019 a total of 55 patients met the inclusion criteria. Eight cases of allergic contact dermatitis were due to anaerobic sealants, seven to dental products, three to windscreen glues, seven to eyelash glues and/or nail products in the beauty sector, three to UV-cured printing inks, two to paints/lacquers, and one to polyester resin system. The origin of these contact allergies was occupational with the exception of four beauty sector workers who had developed eyelid symptoms from eyelash extensions glued onto their own eyelashes. We invariably detected methacrylate monomers in 15 chemical analyses of 12 different anaerobic sealants. CONCLUSIONS: Safety data sheets of anaerobic sealants often lack warnings for skin sensitization, although these products regularly contain sensitizing methacrylates.


Assuntos
Acrilatos/efeitos adversos , Dermatite Alérgica de Contato/diagnóstico , Dermatite Alérgica de Contato/etiologia , Dermatite Ocupacional/diagnóstico , Dermatite Ocupacional/etiologia , Adesivos/efeitos adversos , Cosméticos/efeitos adversos , Cianoacrilatos/efeitos adversos , Materiais Dentários/efeitos adversos , Humanos , Tinta , Laca/efeitos adversos , Metilmetacrilatos/efeitos adversos , Pintura/efeitos adversos , Testes do Emplastro , Estudos Retrospectivos
9.
Mar Drugs ; 19(9)2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34564143

RESUMO

Butenolide derivatives have the potential to be effective and environmentally friendly antifouling agents. In the present study, a butenolide derivative was structurally modified into Boc-butenolide to increase its melting point and remove its foul smell. The structurally modified Boc-butenolide demonstrated similar antifouling capabilities to butenolide in larval settlement bioassays but with significantly lower toxicity at high concentrations. Release-rate measurements demonstrated that the antifouling compound Boc-butenolide could be released from polycaprolactone-polyurethane (PCL-PU)-based coatings to inhibit the attachment of foulers. The coating matrix was easily degraded in the marine environment. The performance of the Boc-butenolide antifouling coatings was further examined through a marine field test. The coverage of biofouler on the Boc-butenolide coatings was low after 2 months, indicating the antifouling potential of Boc-butenolide.


Assuntos
4-Butirolactona/análogos & derivados , Incrustação Biológica/prevenção & controle , Carbamatos/farmacologia , Poliésteres/farmacologia , Poliuretanos/farmacologia , 4-Butirolactona/química , 4-Butirolactona/farmacologia , Animais , Carbamatos/química , Larva , Pintura , Poliquetos , Poliésteres/química , Poliuretanos/química , Thoracica
10.
Sensors (Basel) ; 21(21)2021 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-34770474

RESUMO

Pressure-Sensitive Paint (PSP) is a powerful measurement technique to obtain pressure distribution on a model of interest by measuring the emission intensity of the PSP coating with a camera. Since a PSP coating is prepared by applying a solution containing an organic solvent, generally, by sprayer, the properties such as the pressure- and the temperature-sensitivity depends on the skill of the person applying it. This fabrication process is one of the barriers to use of the PSP technique because of the legal restrictions on the use of organic solvents. Thus, a sticker-like PSP coating is useful because it does not require the use of organic solvent and the applying skill. In this study, we have fabricated freestanding Pressure-Sensitive Nano-Sheet (PSNS) by a sacrificial layer process using a spin-coating method. We employed Pt(II) meso-tetra(pentafluorophenyl)porphine (PtTFPP) as a pressure-sensitive dye and poly(1-trimethylsilyl-propyne) (PTMSP) and poly(L-lactic acid) (PLLA) as a polymer binder; thus, the PSNS samples based on PTMSP and PLLA were prepared. The pressure- and the temperature-sensitivity, the lifetime of the luminescence, and the quantum yield of the fabricated PSNS have been investigated. The pressure-sensitivity of PTMSP-based PSNS is higher than that of PLLA-based PSNS. Conversely, the quantum yield of PLLA-based PSNS is higher than that of PTMSP-based PSNS.


Assuntos
Pintura , Polímeros , Humanos , Luminescência , Solventes , Temperatura
11.
J Environ Manage ; 277: 111460, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33254842

RESUMO

This paper addresses the lifecycle cost assessment of a steel girder bridge considering the material costs and maintenance activities along the bridge's lifecycle. A reference highway bridge case study is chosen. It was initially designed using carbon steel S355. Two more steel grades are included in the comparison: high strength carbon steel S460 and duplex stainless steel EN 1.4162. For each design option, fatigue appears to be the driving design criterion for the following critical welded details: transversal stiffeners, cope holes and full penetration butt welds in the flanges. In addition to ultimate limit state verifications, specific attention is therefore given to fatigue through the use of different verification methods: the well-known nominal stress method and the hot spot stress method. It is concluded that the net present value of the lifecycle cost of the stainless steel option is attractive compared to painted the carbon steel options.


Assuntos
Carbono , Aço Inoxidável , Adaptação Psicológica , Pintura , Aço
12.
Langmuir ; 36(6): 1515-1522, 2020 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-31968942

RESUMO

As an alternative to the toxic antifouling paint that minimizes the adhesion force between organic molecules on large surfaces, a paint containing hydrogel particles encapsulating amphiphilic liposomes has been suggested. However, the release rate of liposomes, which is important for maximizing the antifouling performance, has not been adequately explored. We investigated the control of the release rate of liposomes encapsulated in alginate. Monodispersed alginate particles were generated using 3D-printed microfluidic devices, and their sizes were varied through the channel size, flow rate, and alginate concentration in the microfluidic devices ([Formula: see text]). The release rate of liposomes from the alginate particles was experimentally monitored under various conditions: alginate concentration, surrounding solution, and ambient fluid flow. The effects of chemical and mechanical stimuli on the effective diffusion coefficient (Deff) of amphiphilic liposomes were analyzed, and accordingly, the best production conditions for antifouling alginate particles are suggested. This study provides essential physical insights and is useful for optimizing the performance of eco-friendly antifouling paint that includes alginate particles.


Assuntos
Alginatos , Incrustação Biológica , Incrustação Biológica/prevenção & controle , Hidrogéis , Lipossomos , Pintura
13.
Ecotoxicol Environ Saf ; 187: 109812, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31669574

RESUMO

Marine biofouling represents a global economic and ecological challenge. Some marine organisms produce bioactive metabolites, such as steroids, that inhibit the settlement and growth of fouling organisms. The aim of this work was to explore bile acids as a new scaffold with antifouling (AF) activity by using chemical synthesis to produce a series of bile acid derivatives with optimized AF performance and understand their structure-activity relationships. Seven bile acid derivatives were successfully synthesized in moderate to high yields, and their structures were elucidated through spectroscopic methods. Their AF activities were tested against both macro- and microfouling communities. The most potent bile acid against the settlement of Mytilus galloprovincialis larvae was the methyl ester derivative of cholic acid (10), which showed an EC50 of 3.7 µM and an LC50/EC50 > 50 (LC50 > 200 µM) in AF effectiveness vs toxicity studies. Two derivatives of deoxycholic acid (5 and 7) potently inhibited the growth of biofilm-forming marine bacteria with EC50 values < 10 µM, and five bile acids (1, 5, and 7-9) potently inhibited the growth of diatoms, showing EC50 values between 3 and 10 µM. Promising AF profiles were achieved with some of the synthesized bile acids by combining antimacrofouling and antimicrofouling activities. Initial studies on the incorporation of one of these promising bile acid derivatives in polymeric coatings, such as a marine paint, demonstrated the ability of these compounds to generate coatings with antimacrofouling activity.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Ácidos e Sais Biliares/farmacologia , Incrustação Biológica/prevenção & controle , Desinfetantes/farmacologia , Pintura , Animais , Organismos Aquáticos/crescimento & desenvolvimento , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Ácidos e Sais Biliares/síntese química , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Desinfetantes/síntese química , Microalgas/efeitos dos fármacos , Microalgas/crescimento & desenvolvimento , Mytilus/efeitos dos fármacos , Poliuretanos/química , Silicones/química
14.
Environ Res ; 167: 299-306, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30077928

RESUMO

Paints are often used on chopsticks, however, a paucity of studies has assessed metals in the paints and the associated health risk. In this study, total Pb, Cd, Cr, Co, and Ni concentrations in paints were assessed for 72 wood and 29 stainless steel chopsticks with different colors while metal solubilization from paints in simulated saliva, 0.07 M HCl, and 1% citric acid solutions was measured for 9 samples having total Pb > 90 mg kg-1, representing exposure scenarios of mouthing, incidental paint ingestion, and metal migration in food. Results showed that Pb (0.12-500,000 mg kg-1), Cd (0.002-120,000 mg kg-1), Cr (2.2-8400 mg kg-1), Co (0.004-2600 mg kg-1), and Ni (0.10-150,000 mg kg-1) concentrations varied considerably among paint samples. Most samples showed low metal concentrations, however, high metal concentrations were observed in red and green paints on stainless steel chopsticks, while paints on wood chopsticks showed lower metal concentrations. Estimation of daily metal intakes incorporating metal solubilization data in saliva, 0.07 M HCl, and 1% citric acid solutions suggested that the health risk via saliva contact was negligible, while unacceptable health risk was observed for Pb and Cd via their solubilization in 0.07 M HCl and 1% citric acid solutions from paints with high Pb and Cd concentrations. To avoid Pb and Cd exposure, use of metal-based paints on chopsticks should be banned, particularly in countries where food is regularly consumed with chopsticks.


Assuntos
Utensílios de Alimentação e Culinária , Exposição Dietética/análise , Metais Pesados/análise , Pintura/análise , Saliva , Humanos
15.
Am J Public Health ; 107(S1): S97-S103, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28661802

RESUMO

OBJECTIVES: To assess an oral health promotion (OHP) intervention for medical providers' impact on early childhood caries (ECC). METHODS: We implemented a quasiexperimental OHP intervention in 8 federally qualified health centers that trained medical providers on ECC risk assessment, oral examination and instruction, dental referral, and fluoride varnish applications (FVAs). We measured OHP delivery by FVA count at medical visits. We measured the intervention's impact on ECC in 3 unique cohorts of children aged 3 to 4 years in 2009 (preintervention; n = 202), 2011 (midintervention; n = 420), and 2015 (≥ 4 FVAs; n = 153). We compared numbers of decayed, missing, and filled tooth surfaces using adjusted zero-inflated negative binomial models. RESULTS: Across 3 unique cohorts, the FVA mean (range) count was 0.0 (0), 1.1 (0-7), and 4.5 (4-7) in 2009, 2011, and 2015, respectively. In adjusted zero-inflated negative binomial models analyses, children in the 2015 cohort had significantly fewer decayed, missing, and filled tooth surfaces than did children in previous cohorts. CONCLUSIONS: An OHP intervention targeting medical providers reduced ECC when children received 4 or more FVAs at a medical visit by age 3 years.


Assuntos
Cárie Dentária/prevenção & controle , Pessoal de Saúde/educação , Promoção da Saúde , Saúde Bucal , Pré-Escolar , Odontólogos , Diagnóstico Bucal/métodos , Fluoretos , Humanos , Pintura , Fosfatos
16.
Proc Natl Acad Sci U S A ; 111(35): 12679-83, 2014 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-25122675

RESUMO

This work presents an original approach to create holograms based on the optical scattering of plasmonic nanoparticles. By analogy to the diffraction produced by the scattering of atoms in X-ray crystallography, we show that plasmonic nanoparticles can produce a wave-front reconstruction when they are sampled on a diffractive plane. By applying this method, all of the scattering characteristics of the nanoparticles are transferred to the reconstructed field. Hence, we demonstrate that a narrow-band reconstruction can be achieved for direct white light illumination on an array of plasmonic nanoparticles. Furthermore, multicolor capabilities are shown with minimal cross-talk by multiplexing different plasmonic nanoparticles at subwavelength distances. The holograms were fabricated from a single subwavelength thin film of silver and demonstrate that the total amount of binary information stored in the plane can exceed the limits of diffraction and that this wavelength modulation can be detected optically in the far field.


Assuntos
Arte , Holografia/métodos , Nanopartículas/química , Pintura , Cor , Metilmetacrilato/química , Espalhamento de Radiação , Dióxido de Silício/química , Prata/química , Ressonância de Plasmônio de Superfície/métodos , Difração de Raios X/métodos
17.
Int J Mol Sci ; 18(7)2017 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-28703765

RESUMO

Dibromohemibastadin-1 (DBHB) is an already known potent inhibitor of blue mussel phenoloxidase (which is a key enzyme involved in bioadhesion). Within this study, the potentiality of DBHB against microfouling has been investigated. The activity of DBHB was evaluated on key strains of bacteria and microalgae involved in marine biofilm formation and bioassays assessing impact on growth, adhesion and biofilm formation were used. To assess the efficiency of DBHB when included in a matrix, DBHB varnish was prepared and the anti-microfouling activity of coatings was assessed. Both in vitro and in situ immersions were carried out. Confocal Laser Scanning Microscopy (CLSM) was principally used to determine the biovolume and average thickness of biofilms developed on the coatings. Results showed an evident efficiency of DBHB as compound and varnish to reduce the biofilm development. The mode of action seems to be based principally on a perturbation of biofilm formation rather than on a biocidal activity in the tested conditions.


Assuntos
Biofilmes/efeitos dos fármacos , Materiais Revestidos Biocompatíveis/farmacologia , Ecossistema , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Aderência Bacteriana/efeitos dos fármacos , Incrustação Biológica , Contagem de Células , Microalgas/efeitos dos fármacos , Pintura , Plâncton/citologia , Plâncton/efeitos dos fármacos
18.
J Environ Manage ; 197: 41-49, 2017 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-28319832

RESUMO

The study addresses the life cycle cost assessment (LCCA) of steel bridges, focusing on the maintenance activities and the maintenance scenario. Firstly, the unit costs of maintenance activities and their durability (i.e. the time between two activities) are evaluated. Pragmatic data are provided for the environment category C4 and for three activities: Patch Up, Overcoating and Remove & Replace. A comparative LCCA for a typical hypothetic steel girder bridge is carried out, either painted or hot-dip galvanized (HDG), in the environmental class C4. The LCC versus the cumulated life is provided for both options. The initial cost of the steel unpainted option is only 50.3% of the HDG option. It is shown that after 'Overcoating' occurring at 18.5 years, the total Net Present Value (NPV) of the painted option surpasses that of the HDG option. A sensitivity analysis of the NPV to the cost and service life parameters, the escalation and discount rates is then performed. The discount and escalation rates, considerably influences the total LCC, following a non-linear trend. The total LCC decreases with the discount rate increasing and, conversely, increases with the escalation rate increasing. Secondly, the influence of the maintenance scenario on the total LCC is assessed based on a probabilistic approach. A permutation of the three independent maintenance activities assumed to occur six times over the life of the bridge is considered and a probability of occurrence is associated to each unique scenario. The most probable scenarios are then classified according to their NPV or achieved service life. This approach leads to the definition of a cost-effective maintenance scenario i.e. the scenario, within all the considered permutations, that has the minimum LCC in a range of lifespan. Besides, the probabilistic analysis also shows that, whatever the scenario, the return on investment period ranges between 18.5 years and 24.2 years. After that period, the HDG option becomes economic.


Assuntos
Pintura , Aço , Análise Custo-Benefício
19.
Appl Environ Microbiol ; 82(17): 5225-35, 2016 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-27316963

RESUMO

UNLABELLED: Polyurethane (PU) is widely used in many aspects of modern life because of its versatility and resistance. However, PU waste disposal generates large problems, since it is slowly degraded, there are limited recycling processes, and its destruction may generate toxic compounds. In this work, we isolated fungal strains able to grow in mineral medium with a polyester PU (PS-PU; Impranil DLN) or a polyether PU (PE-PU; Poly Lack) varnish as the only carbon source. Of the eight best Impranil-degrading strains, the six best degraders belonged to the Cladosporium cladosporioides complex, including the species C. pseudocladosporioides, C. tenuissimum, C. asperulatum, and C. montecillanum, and the two others were identified as Aspergillus fumigatus and Penicillium chrysogenum The best Impranil degrader, C. pseudocladosporioides strain T1.PL.1, degraded up to 87% after 14 days of incubation. Fourier transform infrared (FTIR) spectroscopy analysis of Impranil degradation by this strain showed a loss of carbonyl groups (1,729 cm(-1)) and N-H bonds (1,540 and 1,261 cm(-1)), and gas chromatography-mass spectrometry (GC-MS) analysis showed a decrease in ester compounds and increase in alcohols and hexane diisocyanate, indicating the hydrolysis of ester and urethane bonds. Extracellular esterase and low urease, but not protease activities were detected at 7 and 14 days of culture in Impranil. The best eight Impranil-degrading fungi were also able to degrade solid foams of the highly recalcitrant PE-PU type to different extents, with the highest levels generating up to 65% of dry-weight losses not previously reported. Scanning electron microscopy (SEM) analysis of fungus-treated foams showed melted and thinner cell wall structures than the non-fungus-treated ones, demonstrating fungal biodegradative action on PE-PU. IMPORTANCE: Polyurethane waste disposal has become a serious problem. In this work, fungal strains able to efficiently degrade different types of polyurethanes are reported, and their biodegradative activity was studied by different experimental approaches. Varnish biodegradation analyses showed that fungi were able to break down the polymer in some of their precursors, offering the possibility that they may be recovered and used for new polyurethane synthesis. Also, the levels of degradation of solid polyether polyurethane foams reported in this work have never been observed previously. Isolation of efficient polyurethane-degrading microorganisms and delving into the mechanisms they used to degrade the polymer provide the basis for the development of biotechnological processes for polyurethane biodegradation and recycling.


Assuntos
Fungos/isolamento & purificação , Fungos/metabolismo , Poliésteres/metabolismo , Poliuretanos/metabolismo , Biodegradação Ambiental , Fungos/classificação , Fungos/genética , Cromatografia Gasosa-Espectrometria de Massas , Pintura/análise , Pintura/microbiologia , Poliésteres/química , Poliuretanos/química , Microbiologia do Solo
20.
J Anat ; 229(4): 582-90, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27329696

RESUMO

Over the years, various vascular injection products have been developed to facilitate anatomical dissections. This study aimed to compare the most commonly used vascular injection products in fresh-frozen and formalin-embalmed cadaver specimens. An overview of the properties, advantages and limitations of each substance was given, and a comparison of vascular infusion procedures in both preservation methods was made. A literature search was performed in order to identify the most commonly used vascular injection products. Acrylic paint, latex, gelatin, silicone, Araldite F and Batson's No. 17 were selected for the study. One fresh-frozen and one embalmed cadaver forearm were infused with each injection product according to a uniform protocol. The curing time, skin- and subcutaneous tissue penetration, degree of filling of the arterial tree, extravasations, consistency of the injected vessels during dissection, and the costs of each injection fluid were noted. There was a large variation between the injection fluids in processing- and curing time, colour intensity, flexibility, fragility, elasticity, strength, toxicity and costs. All fluids were suitable for infusion. The penetration of injection fluid into the skin and subcutaneous tissue was significantly better in fresh-frozen specimens (P = 0.002 and P = 0.009, respectively), with significantly smaller branches casted (P = 0.004). Vascular infusion of fresh-frozen cadaver specimens results in a significantly better filled coloured arterial tree, enabling more detail to be achieved and smaller branches casted. The biomechanical properties of fresh-frozen soft tissues are less affected compared with formalin fixation. All the injection fluids studied are suitable for vascular infusion, but their different properties ensure that certain products and procedures are more suitable for specific study purposes.


Assuntos
Anatomia/métodos , Vasos Sanguíneos/anatomia & histologia , Cadáver , Dissecação , Embalsamamento , Resinas Epóxi , Antebraço , Gelatina , Humanos , Látex , Pintura , Plásticos , Silicones
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