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1.
BMJ Case Rep ; 16(10)2023 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-37899083

RESUMO

We present a unique case of a man presenting with progressive short-term memory deficits over 10+ years who was found to have a large intraventricular cavernoma in the anterior wall of the third ventricle with invasion of medial limbic structures. Identifying intraventricular cavernomas early is crucial to prevent substantial growth and to increase the chance of successful patient outcomes.


Assuntos
Hemangioma Cavernoso do Sistema Nervoso Central , Hemangioma Cavernoso , Terceiro Ventrículo , Masculino , Humanos , Terceiro Ventrículo/diagnóstico por imagem , Terceiro Ventrículo/cirurgia , Hemangioma Cavernoso do Sistema Nervoso Central/cirurgia , Hemangioma Cavernoso/diagnóstico por imagem , Hemangioma Cavernoso/cirurgia , Resultado do Tratamento
2.
Bioresour Technol ; 162: 250-8, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24759640

RESUMO

Wood catalytic pyrolysis using calcium-based materials was studied in an auger reactor at 450°C. Two different catalysts, CaO and CaO·MgO were evaluated and upgraded bio-oils were obtained in both cases. Whilst acidity and oxygen content remarkable decrease, both pH and calorific value increase with respect to the non-catalytic test. Upgrading process was linked to the fact that calcium-based materials could not only fix the CO2-like compounds but also promoted the dehydration reactions. In addition, process simulation demonstrated that the addition of these catalysts, especially CaO, could favour the energetic integration since a lowest circulation of heat carrier between combustor and auger reactor should be needed. An energy self-sustained system was obtained where thermal energy required for biomass drying and for pyrolysis reaction was supplied by non-condensable gas and char combustion, respectively.


Assuntos
Biomassa , Reatores Biológicos , Biotecnologia/instrumentação , Biotecnologia/métodos , Cálcio/farmacologia , Temperatura Alta , Madeira/efeitos dos fármacos , Catálise/efeitos dos fármacos , Carvão Vegetal/química , Gases/análise , Fenóis/análise
3.
Environ Sci Pollut Res Int ; 21(3): 2064-76, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24022101

RESUMO

In order to perform a study of the carcinogenic potential of polycyclic aromatic hydrocarbons (PAH), benzo(a)pyrene equivalent (BaP-eq) concentration was calculated and modelled by a receptor model based on positive matrix factorization (PMF). Nineteen PAH associated to airborne PM10 of Zaragoza, Spain, were quantified during the sampling period 2001-2009 and used as potential variables by the PMF model. Afterwards, multiple linear regression analysis was used to quantify the potential sources of BaP-eq. Five sources were obtained as the optimal solution and vehicular emission was identified as the main carcinogenic source (35 %) followed by heavy-duty vehicles (28 %), light-oil combustion (18 %), natural gas (10 %) and coal combustion (9 %). Two of the most prevailing directions contributing to this carcinogenic character were the NE and N directions associated with a highway, industrial parks and a paper factory. The lifetime lung cancer risk exceeded the unit risk of 8.7 x 10(-5) per ng/m(3) BaP in both winter and autumn seasons and the most contributing source was the vehicular emission factor becoming an important issue in control strategies.


Assuntos
Poluentes Atmosféricos/análise , Carcinógenos/análise , Modelos Químicos , Material Particulado/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluição do Ar/estatística & dados numéricos , Carvão Mineral , Monitoramento Ambiental , Humanos , Modelos Lineares , Estações do Ano , Espanha , Emissões de Veículos/análise
4.
Environ Pollut ; 183: 166-74, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23245526

RESUMO

The total PAH associated to the airborne particulate matter (PM10) was apportioned by one receptor model based on positive matrix factorization (PMF) in an urban environment (Zaragoza city, Spain) during February 2010-January 2011. Four sources associated with coal combustion, gasoline, vehicular and stationary emissions were identified, allowing a good modelling of the total PAH (R(2) = 0.99). A seasonal behaviour of the four factors was obtained with higher concentrations in the cold season. The NE direction was one of the predominant directions showing the negative impact of industrial parks, a paper factory and a highway located in that direction. Samples were classified according to hierarchical cluster analysis obtaining that, episodes with the most negative impact on human health (the highest lifetime cancer risk concentrations), were produced by a higher contribution of stationary and vehicular emissions in winter season favoured by high relative humidity, low temperature and low wind speed.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluição do Ar/estatística & dados numéricos , Atmosfera/química , Cidades/estatística & dados numéricos , Material Particulado/análise , Estações do Ano , Emissões de Veículos/análise
5.
Environ Sci Pollut Res Int ; 20(5): 3240-51, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23089955

RESUMO

Improving knowledge on the apportionment of airborne particulate matter will be useful to handle and fulfill the legislation regarding this pollutant. The main aim of this work was to assess the influence of markers in the source apportionment of airborne PM10, in particular, whether the use of particle polycyclic aromatic hydrocarbon (PAH) and ions provided similar results to the ones obtained using not only the mentioned markers but also gas phase PAH and trace elements. In order to reach this aim, two receptor models: UNMIX and positive matrix factorization were applied to two sets of data in Zaragoza city from airborne PM10, a previously reported campaign (2003-2004) (Callén et al. Chemosphere 76:1120-1129, 2009), where PAH associated to the gas and particle phases, ions and trace elements were used as markers and a long sampling campaign (2001-2009), where only PAH in the particle phase and ions were analyzed. For both campaigns, positive matrix factorization was able to explain a higher number of sources than the UNMIX model. Independently of the sampling campaign and the receptor model used, soil resuspension was the main PM10 source, especially in the warm period (21st March-21st September), where most of the PM10 exceedances were produced. Despite some of the markers of anthropogenic sources were different for both campaigns, common sources associated to different combustion sources (coal, light-oil, heavier-oil, biomass, and traffic) were found and PAH in particle phase and ions seemed to be good markers for the airborne PM10 apportionment.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Tamanho da Partícula , Material Particulado/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Cromatografia por Troca Iônica/métodos , Cidades , Cromatografia Gasosa-Espectrometria de Massas/métodos , Modelos Teóricos , Estações do Ano , Espanha , Espectrometria de Massas em Tandem/métodos
6.
J Environ Monit ; 14(4): 1211-20, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22398666

RESUMO

The particulate matter with an aerodynamic diameter less than or equal to 10 and 2.5 microns respectively (PM10 and PM2.5) constitutes one of the main air pollutants, which is currently regulated in Europe through Directive 2008/50/EC due to its proven harmful effects on human health. In this paper, the airborne PM10 samples collected in Zaragoza city during 2001-2009 were apportioned by statistical tools based on principal component analysis with absolute principal component scores (PCA-APCS). PM10 samples were characterized regarding their concentrations of polycyclic aromatic hydrocarbons (PAH) and water-soluble ions. PAH were analyzed by gas chromatography-mass spectrometry-mass spectrometry detection (GC-MS-MS) and ions were analyzed by ion chromatography. A total of five factors were identified by PCA-APCS corresponding to different anthropogenic and natural sources. This work was focused on analyzing in more detail those samples involving higher negative impact on human health, in particular, PM10 samples exceeding the daily PM10 limit value of 50 µg m(-3) according to Directive 2008/50/EC and samples with concentrations of benzo[a]pyrene (BaP) higher than the upper assessment threshold (BaP > 0.6 ng m(-3)) established by the Directive 2004/107/EC. Most of the exceedances of the daily PM10 limit value were associated with direct and indirect North-African long-range transport. During these exceedances, it was observed that anthropogenic pollution sources slightly decreased with regard to the natural sources. This indicated that episodes of high PM10 could have a natural origin associated with long-range transport from the African continent. On the contrary, those exceedances with regional contribution and samples with BaP concentrations higher than 0.6 ng m(-3) showed an important contribution of anthropogenic pollution sources increasing their negative impact on human health.


Assuntos
Poluentes Atmosféricos/análise , Exposição Ambiental/estatística & dados numéricos , Nível de Saúde , Material Particulado/análise , Poluição do Ar/estatística & dados numéricos , Benzo(a)pireno/análise , Exposição Ambiental/análise , Humanos , Tamanho da Partícula , Hidrocarbonetos Policíclicos Aromáticos/análise , Espanha
7.
J Environ Monit ; 13(2): 319-27, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21152605

RESUMO

Urban areas constitute major pollution sources due to anthropogenic activities located in these areas. Among the legislated air pollutants, the particulate matter with an aerodynamic diameter less than or equal to 10 microns (PM10) and polycyclic aromatic hydrocarbons (PAH) are controlled under Directive 2008/50/EC and Directive 2004/107/EC, respectively due to their adverse health effects. A study was carried out at four urban and rural Spanish areas during the warm and cold seasons in 2008-2009 to quantify 19 PAH associated with the atmospheric PM10 by gas chromatography-mass spectrometry-mass spectrometry detection (GC-MS-MS) with the internal standard method. The particle-bound composition of the analysed PAH was 5 and 10 times greater in industrial and urban areas, respectively when compared to those measured in rural areas. The highest PAH concentrations during the cold period were possibly due to the additional contribution of domestic heating sources and meteorological conditions such as low temperature and solar irradiation. The use of molecular diagnostic ratios indicated that the possible, major PAH pollution sources in the most polluted areas were pyrogenic sources, mainly attributed to petroleum combustion sources (motor vehicle emissions and crude oil combustion). Petrogenic sources related to evaporative emissions also seemed to contribute in the most polluted area during the warm period. Those dates with high carcinogenic character according to the benzo(a)pyrene equivalent (BaP-eq) were also possibly attributed to petroleum combustion sources.


Assuntos
Poluentes Atmosféricos/análise , Material Particulado/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Carcinógenos Ambientais/análise , Cidades , Cromatografia Gasosa-Espectrometria de Massas , Estações do Ano , Espanha
8.
J Hazard Mater ; 180(1-3): 648-55, 2010 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-20457487

RESUMO

The estimation of benzo(a)pyrene (BaP) concentrations in ambient air is very important from an environmental point of view especially with the introduction of the Directive 2004/107/EC and due to the carcinogenic character of this pollutant. A sampling campaign of particulate matter less or equal than 10 microns (PM10) carried out during 2008-2009 in four locations of Spain was collected to determine experimentally BaP concentrations by gas chromatography mass-spectrometry mass-spectrometry (GC-MS-MS). Multivariate linear regression models (MLRM) were used to predict BaP air concentrations in two sampling places, taking PM10 and meteorological variables as possible predictors. The model obtained with data from two sampling sites (all sites model) (R(2)=0.817, PRESS/SSY=0.183) included the significant variables like PM10, temperature, solar radiation and wind speed and was internally and externally validated. The first validation was performed by cross validation and the last one by BaP concentrations from previous campaigns carried out in Zaragoza from 2001-2004. The proposed model constitutes a first approximation to estimate BaP concentrations in urban atmospheres with very good internal prediction (Q(CV)(2)=0.813, PRESS/SSY=0.187) and with the maximal external prediction for the 2001-2002 campaign (Q(ext)(2)=0.679 and PRESS/SSY=0.321) versus the 2001-2004 campaign (Q(ext)(2)=0.551, PRESS/SSY=0.449).


Assuntos
Poluentes Atmosféricos/análise , Benzo(a)pireno/análise , Análise Multivariada , Estações do Ano , Cromatografia Gasosa-Espectrometria de Massas , Espanha
9.
Arch Soc Esp Oftalmol ; 84(11): 569-72, 2009 Nov.
Artigo em Espanhol | MEDLINE | ID: mdl-19967610

RESUMO

CASE REPORT: We present a 37 year-old man with secondary angle closure by neuroepithelial ciliary body cysts. An argon laser peripherical iridoplasty was performed and ultrasound biomicroscopy (UBM) was employed to follow-up. Initially, the patient had a favorable response to treatment, but six months later the cysts and the secondary closed angle reappeared. DISCUSSION: Argon laser peripheral iridoplasty has been proposed as treatment of plateau-like iris configuration resulting from neuroepithelial ciliary body cysts. However, the cysts and, the secondary closed angle could recur in a long-term (Arch Soc Esp Oftalmol 2009; 84: 569-572).


Assuntos
Corpo Ciliar , Doenças da Íris/diagnóstico por imagem , Doenças da Íris/cirurgia , Iris/cirurgia , Lasers de Gás/uso terapêutico , Adulto , Cistos/complicações , Seguimentos , Humanos , Doenças da Íris/etiologia , Doenças da Íris/patologia , Masculino , Microscopia Acústica , Fatores de Tempo , Doenças da Úvea/complicações
10.
Chemosphere ; 76(8): 1120-9, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19443015

RESUMO

Receptor models are useful to understand the chemical and physical characteristics of air pollutants by identifying their sources and by estimating contributions of each source to receptor concentrations. In this work, three receptor models based on principal component analysis with absolute principal component scores (PCA-APCS), Unmix and positive matrix factorization (PMF) were applied to study for the first time the apportionment of the airborne particulate matter less or equal than 10microm (PM10) in Zaragoza, Spain, during 1year sampling campaign (2003-2004). The PM10 samples were characterized regarding their concentrations in inorganic components: trace elements and ions and also organic components: polycyclic aromatic hydrocarbons (PAH) not only in the solid phase but also in the gas phase. A comparison of the three receptor models was carried out in order to do a more robust characterization of the PM10. The three models predicted that the major sources of PM10 in Zaragoza were related to natural sources (60%, 75% and 47%, respectively, for PCA-APCS, Unmix and PMF) although anthropogenic sources also contributed to PM10 (28%, 25% and 39%). With regard to the anthropogenic sources, while PCA and PMF allowed high discrimination in the sources identification associated with different combustion sources such as traffic and industry, fossil fuel, biomass and fuel-oil combustion, heavy traffic and evaporative emissions, the Unmix model only allowed the identification of industry and traffic emissions, evaporative emissions and heavy-duty vehicles. The three models provided good correlations between the experimental and modelled PM10 concentrations with major precision and the closest agreement between the PMF and PCA models.


Assuntos
Poluentes Atmosféricos/análise , Modelos Teóricos , Material Particulado/análise , Análise de Componente Principal/métodos , Cidades , Monitoramento Ambiental , Tamanho da Partícula , Software , Espanha
11.
Arch Soc Esp Oftalmol ; 84(12): 625-30, 2009 Dec.
Artigo em Espanhol | MEDLINE | ID: mdl-20049667

RESUMO

PURPOSE: To report a new technique to explore peripheral vitreous-retinal tractions in patients with acute posterior vitreous detachment. MATERIAL AND METHODS: A population of 65 patients with acute posterior vitreous detachment was studied by panfunduscopic SLO 230 lens and HRA-II to detect peripheral retinal tears and vitreous-retinal tractions. RESULTS: In our study, using indirect ophthalmoscopic exploration, we identified eleven patients with at least one retinal tear. HRA-II combined with the Staurenghi SLO 230 lens was capable of detecting 100% of these lesions. In addition, by means of this technology, we identified dark retinal zones that corresponded to peripheral retinal traction in six patients. None of the 65 patients complained of pain or photophobia during the exploration with this contact lens. Retinal tears and peripheral vitreous-retinal traction were treated by argon laser photocoagulation to create a firm chorioretinal adhesion. In two patients we found new retinal tears in the follow-up, with these new lesions detected by indirect ophthalmoscopy and HRA-II with SLO 230 lens. CONCLUSION: HRA-II with the panfunduscopic Staurenghi SLO 230 lens can complement the exploration of patients with acute posterior vitreous detachment and can help to detect tractional zones that could develop into retinal tears.


Assuntos
Descolamento do Vítreo/patologia , Angiografia , Técnicas de Diagnóstico Oftalmológico/instrumentação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
12.
Chemosphere ; 73(8): 1357-65, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18692862

RESUMO

Gas/particle partitioning of pollutants is an important mechanism determining atmospheric processing and its impact to environmental and human health. In this paper, the gas-particle partitioning of polycyclic aromatic hydrocarbons (PAH) has been studied with the aim of determining the main mechanism of PAH partitioning in Zaragoza (Spain) aerosols. To reach this goal, the ambient concentrations of PAH (gas and particle phase) collected in this city for one year period (2003-2004) have been analyzed. The partitioning between the particle and gas phases was studied according to three different models: the Junge adsorption model, the absorption into the organic matter model using the octanol-air (K(OA)) partition coefficient and the absorption into the organic matter plus the adsorption onto the soot carbon model using the soot-air (K(SA)) partition coefficients. Experimental gas/particle partition coefficients (K(P)) correlated well with the subcooled liquid vapour pressures (P(L)(0)) of PAH but with slopes higher than the expected value of -1. Experimental K(p) values were well fit to the modelled ones when, in addition to absorption into organic matter, adsorption onto the soot carbon was considered. It could be concluded that the main partition mechanism in Zaragoza aerosols was explained by adsorption onto the soot carbon. However, K(p) modelled values were affected by the different thermodynamic parameters related to soot types. The influence of the organic matter and elemental carbon fractions on the K(p) modelling was also studied. The different particle characteristics, local factors, the presence of non-exchangeable fraction and non-equilibrium were considered like main keys to explain deviations of the experimental K(p) values from predictions according to models.


Assuntos
Atmosfera/química , Poluentes Ambientais/isolamento & purificação , Gases/química , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Exposição Ambiental , Modelos Químicos , Entorses e Distensões , Temperatura
13.
Arch Soc Esp Oftalmol ; 81(11): 647-52, 2006 Nov.
Artigo em Espanhol | MEDLINE | ID: mdl-17136638

RESUMO

PURPOSE: To show the utility of optical coherence tomography (OCT) for studying the anterior segment and to explain its potential advantages as compared to ultrasonic biomicroscopy (UBM). MATERIALS AND METHODS: We have described the findings in 5 patients with different pathologies of the anterior segment, all of whom were studied with UBM and OCT-3 adjusted for the anterior segment. There were 2 cases of an acute attack of closed angle glaucoma, 1 case of rubeosis iridis, 1 case of penetrating ocular trauma and 1 case of a primary stromal iris cyst. RESULTS: OCT was found to be as useful as UBM in detecting angle closure in patients affected by an acute attack of glaucoma. In addition, OCT was more comfortable for the patient and faster than UBM in obtaining images, with the exploration mean time using OCT being less than five minutes while that with UBM was over ten minutes. OCT has also been demonstrated to be a safe and valuable non-contact examination in other iris pathologies such as rubeosis iridis, for checking the permeability of iridotomies and even for studying iris masses such as primary stromal iris cysts. In these entities OCT may reach a higher resolution than ultrasonic biomicroscopy. CONCLUSION: OCT-3, with an adjustable focus, can obtain images from the scleral angle, as well as from other ocular structures like the iris, thus assisting in the diagnosis of numerous pathologies.


Assuntos
Segmento Anterior do Olho , Oftalmopatias/diagnóstico , Glaucoma/diagnóstico , Tomografia de Coerência Óptica , Adulto , Feminino , Humanos , Masculino , Microscopia Acústica , Pessoa de Meia-Idade
14.
Arch Soc Esp Oftalmol ; 80(8): 479-82, 2005 Aug.
Artigo em Espanhol | MEDLINE | ID: mdl-16136403

RESUMO

OBJECTIVE: Primary intraorbital mucoceles arising from the optic canal are extremely rare. We describe a patient with compressive optic neuropathy caused by an intraorbital mucocele. CLINICAL CASE: A 51-year-old woman presented with proptosis and reduced vision. Magnetic resonance imaging showed a mass compressing the optic nerve. There was no direct connection between any paranasal sinus and the mass cavity, as assessed in imaging studies and intraoperatively confirmed. The pathological diagnosis after the operation indicated a mucocele. DISCUSSION: Considering the absence of air pockets in the orbit, the mucocele might have originated from ectopic mucinous tissue that appeared during the development of the optic canal.


Assuntos
Exoftalmia/etiologia , Mucocele , Atrofia Óptica/etiologia , Doenças Orbitárias , Diagnóstico Diferencial , Feminino , Seguimentos , Humanos , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Mucocele/complicações , Mucocele/diagnóstico , Mucocele/diagnóstico por imagem , Mucocele/cirurgia , Doenças Orbitárias/diagnóstico por imagem , Doenças Orbitárias/cirurgia , Fatores de Tempo , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Acuidade Visual
15.
Environ Res ; 99(1): 58-67, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16053928

RESUMO

An assessment of the air quality of Zaragoza (Spain) was performed by determining the trace element content in airborne PM10 in a sampling campaign from July 2001 to July 2002. Samples were collected in a heavy traffic area with a high volume air sampler provided with a PM10 cutoff inlet. The levels of 16 elements (Al, Ba, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, V, and Zn) were quantified after collecting the PM10 on Teflon-coated glass fiber filters (GFF). Regarding the PM10, 32% exceedance of the proposed PM10 daily limit was obtained, some of them corresponding to summer and autumn periods. The limit values of toxic trace elements from US-EPA, WHO, and EC were not exceeded, considering Zaragoza as a moderately polluted city under the current air quality guidelines. The contribution of anthropogenic sources to atmospheric elemental levels was reflected by the high values of enrichment factors for Zn, Pb, and Cu compared to the average crustal composition. Statistical analyses also determined the contribution of different sources to the PM10, finding that vehicle traffic and anthropogenic emissions related to combustion and industrial processes were the main pollutant sources as well as natural sources associated with transport of dust from Africa for specific dates. Regarding the influence of meteorological conditions on PM10 and trace elements concentrations, it was found that calm weather conditions with low wind speed favor the PM10 collection and the pollution for trace elements, suggesting the influence of local sources.


Assuntos
Poluentes Atmosféricos/análise , Ar/análise , Metais Alcalinos/análise , Metais Pesados/análise , Ar/normas , Cidades , Monitoramento Ambiental , Tamanho da Partícula , Espanha
16.
Arch. Soc. Esp. Oftalmol ; 80(8): 479-482, ago. 2005. ilus
Artigo em Es | IBECS | ID: ibc-040869

RESUMO

Objetivo: Los mucoceles orbitarios primarios que crecen desde el canal óptico son extremadamente raros. Describimos una paciente con neuropatía óptica compresiva secundaria a un mucocele intraorbitario.Caso clínico: Una mujer de 51 años presentó proptosis y disminución de visión. La Resonancia Magnética Nuclear mostró una masa que comprimía el nervio óptico. No había comunicación entre los senos paranasales y la masa orbitaria, como se confirmó en los estudios de imagen y posteriormente en el intraoperatorio. El estudio anatomopatológico confirmó un mucocele.Discusión: Considerando la ausencia de neumatización de la órbita, el mucocele debe originarse de tejido mucinoso ectópico que aparece durante el desarrollo del canal óptico


Objective: Primary intraorbital mucoceles arising from the optic canal are extremely rare. We describe a patient with compressive optic neuropathy caused by an intraorbital mucocele. Clinical case: A 51-year-old woman presented with proptosis and reduced vision. Magnetic resonance imaging showed a mass compressing the optic nerve. There was no direct connection between any paranasal sinus and the mass cavity, as assessed in imaging studies and intraoperatively confirmed. The pathological diagnosis after the operation indicated a mucocele. Discussion: Considering the absence of air pockets in the orbit, the mucocele might have originated from ectopic mucinous tissue that appeared during the development of the optic canal


Assuntos
Feminino , Humanos , Exoftalmia/etiologia , Mucocele/complicações , Mucocele/diagnóstico , Mucocele , Mucocele/cirurgia , Doenças Orbitárias , Doenças Orbitárias/cirurgia , Atrofia Óptica/etiologia , Diagnóstico Diferencial , Seguimentos , Imageamento por Ressonância Magnética , Fatores de Tempo , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Acuidade Visual
17.
Environ Sci Technol ; 36(8): 1821-6, 2002 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-11993882

RESUMO

Three-ring polycyclic aromatic hydrocarbons (PAH) are one of the most abundant PAH groups emitted during coal combustion. Four of them-acenaphthene (Ac), phenanthrene (Phe), fluorene (Fu), and anthracene (An)-have been listed by the U.S. EPA as priority pollutants. The aim in this paper is to study the abatement of this particular group of three-ring PAH from hot gas emissions during energy generation in coal combustion. The three-ring PAH adsorption capacities are related to the morphological and chemical properties of the 16 sorbents used in this work. Single and multiple linear regressions-principal component regression (PCR)-were applied in this study. The main conclusions reached are, first, that the micropore volume is the most determinant parameter for removal of these PAHs and, second, that the adsorption of three-ring PAH by sorbents from waste hot gas emissions is inversely proportional to their volatility: the lower the PAH volatility, the higher the adsorbent adsorption capacity. The adsorption isotherms show that Phe and An, both examples of PAH with three aromatic rings, behave similarly. However, their behavior differs from that of Ac and Fu, compounds in which only two of their three rings exhibit an aromatic nature.


Assuntos
Poluição do Ar/prevenção & controle , Carvão Mineral , Hidrocarbonetos Policíclicos Aromáticos/análise , Adsorção , Gases , Incineração , Hidrocarbonetos Policíclicos Aromáticos/química , Temperatura , Volatilização
19.
Environ Sci Technol ; 35(13): 2645-9, 2001 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-11452587

RESUMO

The main aim of this work was the analyzing of the release to the atmosphere of benzo[a]pyrene (BaP), dibenzo(a,h)anthracene (D(a,h)A), and benzo[a]anthracene (BaA), three of the most carcinogenic PAHs listed by US-EPA as priority pollutants, emitted from combustion at the last generation reactors used nowadays in power generation, fluidized bed reactors, trying to establish their incidence when waste materials are used as "new fuels". BaP, D(a,h)A, and BaA emissions, once collected in the sampling system, have been analyzed by fluorescence spectroscopy in the synchronous mode (FS) after extraction by ultrasonic bath with dimethylformamide (DMF) as solvent. Concerning to the combustion variables influence, the conclusion reached was that, in coal combustion, the lowest emissions of BaP are generated at percentages of excess oxygen of 20%, at flows corresponding to good fluidization conditions, 860 L/h (double of the minimum fluidization velocity) and temperatures out of 850 degrees C; the lowest emission of D(a,h)A are emitted at 20% excess oxygen, 900 L/h and out of 750 degrees C, and the lowest emission of BaA are generated at 20% excess oxygen, 860 L/h and out of the range 750-850 degrees C. Regarding tire as nonfossil fuel, higher emissions of BaP, BaA, and D(a,h)A are detected in comparison to coal combustion. In coal-tire blend, the BaP, BaA, and D(a,h)A emissions are more similar to the values obtained in coal combustion and not intermediate values as it could be expected by the blend composition.


Assuntos
Poluentes Atmosféricos/análise , Benzo(a)Antracenos/análise , Benzo(a)pireno/análise , Carcinógenos/análise , Eliminação de Resíduos , Carvão Mineral , Monitoramento Ambiental , Incineração , Indústrias , Oxigênio/análise
20.
Environ Sci Technol ; 35(11): 2395-400, 2001 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-11414051

RESUMO

It is the first time that the removal of polycyclic aromatic hydrocarbons (PAH) containing different aromatic rings number [naphthalene (Np), phenanthrene (Phe), and pyrene (Py)] from combustion hot gas has been carried out. The aim was to relate the sorbents textural characteristics with the adsorption capacity of these 2-4-ring PAH at the conditions emitted at energy generation. The sorbents textural parameters [total micropore volume (VN2), narrow micropore volume (VCO2), mesopore volume (VBJH), and the free active sites] were analyzed trying to correlate them with their Np, Phe, and Py adsorption capacities. To get this aim, single and multiple linear regressions (MLR) were applied to the three PAH. A principal component analysis was performed to generate new and uncorrelated variables. It enabled us to show that the relations between the textural parameters were analyzed using a principal components regression (PCR). The PCR analysis had a good statistical quality, but neither did it allow differentiating free active site types nor did VN2 and VCO2. The correlations were thus set up applying a MLR to the original variables. The regression statistical quality was similar to the PCR analysis, and it could give an easier explanation of the parameters that affected the adsorption. In Np adsorption, the 87% data variance was explained, and the adsorption was positively correlated to VCO2 and the micropore mean diameter (I.). In the Phe regression there was 98% variance explained, and its adsorption was positively correlated to the VN2 and the micropore distribution, n. Finally, in the Py adsorption, the 96% data variance was explained, and this adsorption was positively correlated to VN2 and VBJH. These dependencies were according to the molecular parameters of these compounds (molecular diameter and volatility) because the higher the number of aromatic rings of the PAH, the more favored the adsorbate-adsorbate interactions. Besides, the higher the mean diameter micropores, the lower the diffusional problems showed by Np, Phe, and Py.


Assuntos
Poluição do Ar/prevenção & controle , Naftalenos/química , Fenantrenos/química , Pirenos/química , Adsorção , Gases , Incineração , Centrais Elétricas , Análise de Regressão
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