Color-space distortions following long-term occupational exposure to mercury vapor

Color vision was examined in subjects with long-term occupational exposure to mercury (Hg) vapor. The color vision impairment was assessed by employing a quantitative measure of distortion of individual and group perceptual color spaces. Hg subjects (n = 18; 42.1 +/- 6.5 years old; exposure time = 10.4 +/- 5.0 years; time away from the exposure source = 6.8 +/- 4.6 years) and controls (n = 18; 46.1 +/- 8.4 years old) were examined using two arrangement tests, D-15 and D-15d, in the traditional way, and also in a triadic procedure. From each subject`s `odd-one-out` choices, matrices of inter-cap subjective dissimilarities were derived and processed by non-metric multidimensional scaling (MDS). D-15d results differed significantly between the Hg-group and the control group (p < 0.05), with the impairment predominantly along the tritan axis. 2D perceptual color spaces, individual and group, were reconstructed, with the dimensions interpreted as the red-green (RG) and the blue-yellow (BY) systems. When color configurations from the Hg-group were compared to those of the controls, they presented more fluctuations along both chromatic dimensions, indicating a statistically significant difference along the BY axis. In conclusion, the present findings confirm that color vision impairments persist in subjects that have received long-term occupational exposure to Hg-vapor although, at the time of testing, they were presenting mean urinary concentration within the normal range for non-exposed individuals. Considering the advantages of the triadic procedure in clinical evaluation of acquired color vision deficiencies, further studies should attempt to verify and/or improve its efficacy.

Preliminary Findings on the Effects of Occupational Exposure to Mercury Vapor Below Safety Levels on Visual and Neuropsychological Functions

Objective: To evaluate whether there are visual and neurophysical decrements in workers with low exposure to Hg vapor. Methods: Visual fields, contrast sensitivity, color vision, and neuropsychological functions were measured in 10 workers (32.5 +/- 8.5 years) chronically exposed to Hg vapor (4.3 +/- 2.8 years; urinary Hg concentration 22.3 +/- 9.3 mu g/g creatinine). Results: For the worst eyes, we found altered visual field thresholds, lower contrast sensitivity, and color discrimination compared with controls (P < 0.05). There were no significant differences between Hg-exposed subjects and controls on. neuropsychological tests. Nevertheless, duration of exposure was statistically correlated to verbal memory and depression scores. Conclusions: Chronic exposure to Hg vapor at currently accepted safety levels was found to be associated with visual losses but not with neuropsychological dysfunctions in the sample of workers studied. (J Occup Environ Med. 2009,51:1403-1412)

Irreversible color vision losses in patients with chronic mercury vapor intoxication

This longitudinal study addresses the reversibility of color vision losses in subjects who had been occupationally exposed to mercury vapor. Color discrimination was assessed in 20 Hg-exposed patients (mean age = 42.4 +/- 6.5 years; 6 females and 14 males) with exposure to Hg vapor during 10.5 +/- 5.3 years and away from the work place (relative to 2002) for 6.8 +/- 4.2 years. During the Hg exposure or up to one year after ceasing it, mean urinary Hg concentration was 47 +/- 35.4 mu g/g creatinine. There was no information on Hg urinary concentration at the time of the first tests, in 2002 (Ventura et al., 2005), but at the time of the follow-up tests, in 2005, this value was 1.4 +/- 1.4 mu g/g creatinine for patients compared with 0.5 +/- 0.5 mu g/g creatinine for controls (different group from the one in Ventura et al. (2005)). Color vision was monocularly assessed using the Cambridge Colour Test (CCT). Hg-exposed patients had significantly worse color discrimination (p < 0.02) than controls, as evaluated by the size of MacAdam`s color discrimination ellipses and color discrimination thresholds along protan, deutan, and tritan confusion axes. There were no significant differences between the results of the study in Ventura et al. (2005) and in the present follow-up measurements, in 2005, except for worsening of the tritan thresholds in the best eye in 2005. Both chromatic systems, blue-yellow and red-green, were affected in the first evaluation (Ventura et al., 2005) and remained impaired in the follow-up testing, in 2005. These findings indicate that following a long-term occupational exposure to Hg vapor, even several years away from the source of intoxication, color vision impairment remains irreversible.

Visual field losses in workers exposed to mercury vapor

Visual field losses associated with mercury (Hg) exposure have only been assessed in patients exposed to methylmercury. Here we evaluate the automated visual field in 35 ex-workers (30 males; 44.20+/-5.92 years) occupationaly exposed to mercury vapor and 34 controls (21 males; 43.29+/-8.33 years). Visual fields were analyzed with the Humphrey Field Analyzer II (model 750i) using two tests: the standard automated perimetry (SAP, white-on-white) and the short wavelength automated perimetry (SWAP, blue-on-yellow) at 76 locations within a 27 degrees central visual field. Results were analyzed as the mean of the sensitivities measured at the fovea, and at five successive concentric rings, of increasing eccentricity, within the central field. Compared to controls, visual field sensitivities of the experimental group measured using SAP were lower for the fovea as well as for all five eccentricity rings (p<0.05). Sensitivities were significantly lower in the SWAP test (p<0.05) for four of the five extra-foveal eccentricity rings; they were not significant for the fovea (p = 0.584) or for the 15 degrees eccentricity ring (p = 0.965). These results suggest a widespread reduction of sensitivity in both visual field tests. Previous reports in the literature describe moderate to severe concentric constriction of the visual field in subjects with methylmercury intoxication measured manually with the Goldman perimeter. The present results amplify concerns regarding potential medical risks of exposure to environmental mercury sources by demonstrating significant and widespread reductions of visual sensitivity using the more reliable automated perimetry. (C) 2007 Elsevier Inc. All rights reserved.

Electrophysiological evidence for impairment of contrast sensitivity in mercury vapor occupational intoxication

Contrast sensitivity (CS) was evaluated in 41 former workers from a lamp manufacturing plant who were on disability retirement due to exposure to mercury and 14 age-matched controls. The CS was measured monocularly using the sweep visual evoked potential (sVEP) paradigm at 6 spatial frequencies (0.2, 0.8, 2.0, 4.0, 15.0, and 30 cpd). Statistical difference (p < 0.05) was found between the controls and the patient right and left eyes for 2.0 and 4.0 cpd. According the results in those spatial frequencies the eyes were classified in best and worst. Statistical differences were found between the controls and the best eyes for 2.0 and 4.0 cpd and for 0.8, 2.0, and 4.0 cpd for their worst eyes. No correlation was found between CS results and the time of exposure (mean 8.9 yr +/- 4.1), time away from the mercury source (mean = 6.0 yr +/- 3.9), urinary mercury level at the time of work (mean = 40.6 mu g/g +/-36.3) or with the mercury level at the CS measurement time (mean = 1.6 mu g/g +/-1.1). We show the first evidence of a permanent impairment in CS measured objectively with the sVEP. Our data complement the previous psychophysical works reporting a diffuse impairment in the CS function showing a CS reduction in the low to middle spatial frequencies. In conclusion, non-reversible CS impairment was found in occupational exposure to mercury vapor. We suggest that CS measurement should be included in studies of the mercury effects of occupational exposure. (C) 2007 Elsevier Inc. All rights reserved.

Effect of humidity and solvent vapor phase on cellulose esters films

In the present study the effect of relative humidity (RH) during spin-coating process on the structural characteristics of cellulose acetate (CA), cellulose acetate phthalate (C-A-P), cellulose acetate butyrate (CAB) and carboxymethyl cellulose acetate butyrate (CMCAB) films was investigated by means of atomic force microscopy (AFM), ellipsometry and contact angle measurements. All polymer solutions were prepared in tetrahydrofuran (THF), which is a good solvent for all cellulose esters, and used for spin-coating at RH of (35 +/- A 5)%, (55 +/- A 5)% or (75 +/- A 5)%. The structural features were correlated with the molecular characteristics of each cellulose ester and with the balance between surface energies of water and THF and interface energy between water and THF. CA, CAB, CMCAB and C-A-P films spin-coated at RH of (55 +/- A 5)% were exposed to THF vapor during 3, 6, 9, 60 and 720 min. The structural changes on the cellulose esters films due to THF vapor exposition were monitored by means of AFM and ellipsometry. THF vapor enabled the mobility of cellulose esters chains, causing considerable changes in the film morphology. In the case of CA films, which are thermodynamically unstable, dewetting was observed after 6 min exposure to THF vapor. On the other hand, porous structures observed for C-A-P, CAB and CMCAB turned smooth and homogeneous after only 3 min exposure to THF vapor.

WATER VAPOR CONDUCTANCE OF THE LOWER CRETACEOUS DINOSAURIAN EGGS FROM SANAGASTA, LA RIOJA, ARGENTINA: PALEOBIOLOGICAL AND PALEOECOLOGICAL IMPLICATIONS FOR SOUTH AMERICAN FAVEOLOOLITHID AND MEGALOOLITHID EGGS

The water vapor conductance (G(H20)) of the neosauropod eggs from the Lower Cretaceous Sanagasta nesting site in La Rioja Province, Argentina, was examined and compared with other Cretaceous Argentinean oological material. The 2900 mgH(2)O/day.Torr G(H2O) of the Sanagasta eggshells confirms an extremely moist nesting environment and supports field observations of dug-out nests in a geothermal setting. The observed thinning of the outer eggshell surface during incubation increases gas conductance and concomitantly decreases eggshell mechanical resistance during the late ontogenetic stages, thus facilitating embryonic development and hatching. The Sanagasta and Entre Rios Province faveoloolithid eggs display the highest and comparable 61120 values and share several morphological and diagenetic characters, indicating comparable nesting strategy in geothermal settings. However, the faveoloolithid Yamintie and La Pampa Province specimens cluster together with lower G(H20) values closer to the megaloolithid eggs. The Gnu) of the megaloolithid egg Megaloolithus patagonicus was reconsidered and new results are now congruent with other reported megaloolithid GH2O values. Additionally, we hypothesize that V-shaped pore canals of M. patagonicus, which upper sections reach only the top third or half eggshell thickness and, a wider section in the middle would not compromise the overall egg mechanical resistance like vertical pores connecting directly the outer to the inner eggshell surfaces. Such pore spatial arrangement and geometry would enhance, as the eggshell thins during incubation, a greater G(H2O), G(O2) and G(CO2) and facilitate embryonic development in high moisture nesting contents. Overall, data suggests that neosauropod nesting and brooding behaviors were dependent on elevated moisture nesting environments.

Ionic Transport and Water Vapor Uptake of Ammonium Exchanged Perfluorosulfonic Acid Membranes

Nafion membranes series N117 doped with ammonium, at different cation fractions (H+/NH4+), were investigated for ionic transport and water vapor uptake, for several water activities and temperatures. Ammonium cations change both properties of the polymer in a similar manner. Membrane ionic conductivity and water vapor uptake (lambda) decrease as the ammonium concentration increases in the polymer. Ionic transport activation energies are calculated and the transport mechanism of ammonium ions in Nafion is discussed. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.040203jes] All rights reserved.

UV-Ozone Generation from Modified High Intensity Discharge Mercury Vapor Lamps for Treatment of Indium Tin Oxide Films

In a homemade UV-Ozone generator, different ignition tubes extracted from HID mercury vapor lamps were investigated, namely: 80, 125, 250 and 400 watts. The performance of the generator in function of the type of the ignition lamp was monitored by the measurements of the ozone concentration and the temperature increment. The results have shown that the 400 W set up presented the highest ozone production, which was used in the treatment of indium tin oxide (ITO) films. Polymer light emitting diodes were assembled using ITO films, treated for 10, 20 and 30 min, as an anode. The overall results indicate improvement of the threshold voltage (reduction) and electroluminescence of these devices.

Fatores maternos e neonatais associados ao mecônio no líquido amniótico em um centro de parto normal

OBJETIVO: Analisar a frequência e os fatores maternos e neonatais associados ao mecônio no líquido amniótico no parto. MÉTODOS: Estudo transversal com 2.441 nascimentos em um centro de parto normal hospitalar em São Paulo, SP, em março e abril de 2005. A associação entre mecônio no líquido amniótico e as variáveis independentes (idade materna, paridade, ter ou não cesariana prévia, idade gestacional, antecedentes obstétricos, uso de ocitocina no trabalho de parto, dilatação cervical na admissão, tipo do parto atual, peso do RN, índice de Apgar de 1º e 5º minutos de vida) foi expressa como razão de prevalência. RESULTADOS: Verificou-se mecônio no líquido amniótico em 11,9% dos partos; 68,2% desses foram normais e 38,8%, cesarianas. O mecônio esteve associado a: primiparidade (RP = 1,49; IC95% 1,29;1,73), idade gestacional ≥ 41 semanas (RP = 5,05; IC95% 1,93;13,25), ocitocina no parto (RP = 1,83, IC95% 1,60;2,10), cesariana (RP = 2,65; IC95% 2,17;3,24) e índice de Apgar < 7 no 5º minuto (RP = 2,96, IC95% 2,94;2,99). A mortalidade neonatal foi 1,6/1.000 nascidos vivos; mecônio no líquido amniótico foi encontrado em 50% das mortes neonatais e associado a maiores taxas de partos cirúrgicos. CONCLUSÕES: Emprego de ocitocina, piores condições do recém-nascido logo após o parto e aumento de taxas de cesariana foram fatores associados ao mecônio. A utilização rotineira de ocitocina no intraparto poderia ser revista por sua associação com mecônio no líquido amniótico.

Efeito da adição de lantânio em catalisadores de Ni/ZrO2 aplicados na reação de reforma a vapor de etanol

The catalytic performance of Ni/ZrO2 catalysts loaded with different lanthanum content for steam reforming of ethanol was investigated. Catalysts were characterized by BET surface area, X-ray diffraction, UV-vis spectroscopy, temperature programmed reduction, and X-ray absorption fine structure techniques. Results showed that lanthanum addition led to an increase in the degree of reduction of both NiO and nickel surface species interacting with the support, due to the higher dispersion effect. The best catalytic performance at 450 ºC was found for the Ni/12LZ catalyst, which exhibited an effluent gaseous mixture with the highest H2 yield.

Desenvolvimento e validação de método analítico para quantificação do fármaco bevacizumabe por cromatografia a líquido de alta eficiência

In this study, an analytical method was developed and validated for quantitation of the drug bevacizumab (Avastin®) by high performance liquid chromatography (HPLC). The HPLC column was a BioSuite 250® HR SEC, 300 x 7.8 mm x 5 µm (Waters, USA). The mobile phase consisted of phosphate buffered saline (PBS). The results revealed that the method was specific, precise, accurate, robust and linear (r² = 0.998) from 5 to 75 µg mL-1. Therefore, this method can be used in drug release studies or in quality control ampoules of the drug.

Equilíbrio estático e dinâmico no indivíduo com espondilite anquilosante: revisão da literatura

Com o objetivo de analisar as alterações musculoesqueléticas dos indivíduos com espondilite anquilosante (EA) e suas repercussões sobre o controle postural, realizou-se uma revisão bibliográfica nas bases de dados da BIREME e EBSCO HOTS e no site Pubmed com as palavras-chave: "ankylosing spondylitis", "postural balance" e "posture". Foram selecionados artigos envolvendo seres humanos e que analisavam o controle postural e a biomecânica dos indivíduos com EA, nos idiomas inglês e português, publicados no período entre 1999 e 2010. Do total de artigos encontrados, apenas quatro preencheram os requisitos. Desses, três compararam os resultados de pacientes com EA com os dados obtidos de indivíduos saudáveis, e um analisou apenas indivíduos com EA. Nenhum artigo continha o mesmo método de análise postural. Para avaliação do equilíbrio foram utilizadas a Escala de Equilíbrio de Berg, a Plataforma de Força e a Magnometria. Os principais desvios posturais encontrados foram aumento da cifose torácica e flexão do quadril, que levam a uma anteriorização do centro de gravidade corporal, apresentando flexão do joelho e plantiflexão do tornozelo como compensação para manter o equilíbrio. Apenas um autor encontrou piora do equilíbrio funcional nos sujeitos com EA. Todos os métodos de avaliação utilizados foram considerados capazes de mensurar o equilíbrio, não havendo uma escala específica para pacientes com EA.

Análise do controle do equilíbrio em surfistas durante a postura ereta

INTRODUÇÃO: O surfe é uma modalidade que tem crescido bastante, aumentando o interesse nas pesquisas interessadas nos aspectos que podem influenciar no desempenho desses atletas, como, por exemplo, lesões, aptidão aeróbia e tempo de reação. Devido ao ambiente em constante mudança e de alta instabilidade exigido na prática do surfe, é necessário que os surfistas desenvolvam habilidades neuromusculares (agilidade, equilíbrio, força muscular e flexibilidade) para obter um melhor desempenho nesta atividade esportiva. No entanto, ainda são escassos os trabalhos científicos que se preocupam em investigar tais capacidades motoras em surfistas. OBJETIVO: O objetivo deste estudo foi avaliar o controle do equilíbrio em surfistas amadores em relação aos praticantes de outras atividades físicas. MÉTODOS: Os participantes permaneceram sobre uma plataforma de força enquanto realizavam tarefas que envolviam privação visual (olhos abertos ou fechados) e perturbação somatossensorial (superfície firme ou uso de espuma), com covariação das condições experimentais. As seguintes variáveis foram analisadas: velocidade e raiz quadrática média (RMS) do deslocamento do centro de pressão nas direções anteroposterior (AP) e mediolateral (ML). RESULTADOS: Os resultados mostraram que não houve diferença entre os grupos, durante as condições experimentais, isto é, tanto surfistas quanto grupo controle oscilaram mais nas condições de olhos fechados e sobre espuma. CONCLUSÃO: Apesar de o surfe exigir, por parte do esportista, uma grande capacidade em controlar o equilíbrio, os resultados não revelaram relação entre a prática deste esporte e um melhor desempenho no controle do equilíbrio. Porém, devemos considerar o reduzido tamanho da amostra e o fato de a modalidade exigir um equilíbrio dinâmico, enquanto o estudo avaliou o equilíbrio estático.

Equilíbrio, controle postural e força muscular em idosas osteoporóticas com e sem quedas

Um dos maiores problemas de saúde pública na população idosa são as quedas, agravando-se quando relacionadas à presença de osteoporose. Dentre os vários fatores de risco, destacam-se a diminuição do equilíbrio, controle postural e força muscular. O objetivo deste trabalho foi comparar o equilíbrio, o controle postural e a força muscular em idosas osteoporóticas com e sem quedas referidas no último ano. Foram avaliadas 45 mulheres entre 65 e 85 anos, divididas em dois grupos com base no relato de quedas nos 12 meses anteriores à avaliação: grupo com quedas (GCQ; n=21) e grupo sem quedas (GSQ; n=24). O equilíbrio foi avaliado por meio da escala de equilíbrio de Berg; o controle postural pelo teste clínico modificado de interação sensorial no equilíbrio (mCTSIB), realizado no equipamento Balance Master®; e a força muscular dos flexores e extensores de joelho e dorsiflexores de tornozelo, com dinamômetro EMG System do Brasil®. Foi considerado nível de significância α=0,05. Houve diferença significativa no equilíbrio (p<0,01) e na velocidade de oscilação do Centro de Pressão (CP) durante o teste mCTSIB nas condições olhos fechados superfície estável (p=0,05) e olhos abertos superfície instável (p<0,01), com valores maiores para o GCQ. Os grupos foram semelhantes entre si em relação à força muscular (p>0,05). Nossos resultados indicam que idosas osteoporóticas com histórico de quedas nos últimos 12 meses possuem pior equilíbrio e controle postural em relação às osteoporóticas sem quedas referidas.