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1.
Remote Sens Environ ; 289: 113514, 2023 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-36846486

RESUMO

Atmospheric pollutant data retrieved through satellite sensors are continually used to assess changes in air quality in the lower atmosphere. During the COVID-19 pandemic, several studies started to use satellite measurements to evaluate changes in air quality in many different regions worldwide. However, although satellite data is continuously validated, it is known that its accuracy may vary between monitored areas, requiring regionalized quality assessments. Thus, this study aimed to evaluate whether satellites could measure changes in the air quality of the state of São Paulo, Brazil, during the COVID-19 outbreak; and to verify the relationship between satellite-based data [Tropospheric NO2 column density and Aerosol Optical Depth (AOD)] and ground-based concentrations [NO2 and particulate material (PM; coarse: PM10 and fine: PM2.5)]. For this purpose, tropospheric NO2 obtained from the TROPOMI sensor and AOD retrieved from MODIS sensor data by using the Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm were compared with concentrations obtained from 50 automatic ground monitoring stations. The results showed low correlations between PM and AOD. For PM10, most stations showed correlations lower than 0.2, which were not significant. The results for PM2.5 were similar, but some stations showed good correlations for specific periods (before or during the COVID-19 outbreak). Satellite-based Tropospheric NO2 proved to be a good predictor for NO2 concentrations at ground level. Considering all stations with NO2 measurements, correlations >0.6 were observed, reaching 0.8 for specific stations and periods. In general, it was observed that regions with a more industrialized profile had the best correlations, in contrast with rural areas. In addition, it was observed about 57% reductions in tropospheric NO2 throughout the state of São Paulo during the COVID-19 outbreak. Variations in air pollutants were linked to the region economic vocation, since there were reductions in industrialized areas (at least 50% of the industrialized areas showed >20% decrease in NO2) and increases in areas with farming and livestock characteristics (about 70% of those areas showed increase in NO2). Our results demonstrate that Tropospheric NO2 column densities can serve as good predictors of NO2 concentrations at ground level. For MAIAC-AOD, a weak relationship was observed, requiring the evaluation of other possible predictors to describe the relationship with PM. Thus, it is concluded that regionalized assessment of satellite data accuracy is essential for assertive estimates on a regional/local level. Good quality information retrieved at specific polluted areas does not assure a worldwide use of remote sensor data.

2.
Environ Res ; 198: 111255, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33971134

RESUMO

Mobility restrictions are among actions to prevent the spread of the COVID-19 pandemic and have been pointed as reasons for improving air quality, especially in large cities. However, it is crucial to assess the impact of atmospheric conditions on air quality and air pollutant dispersion in the face of the potential variability of all sources. In this study, the impact of mobility restrictions on the air quality was analyzed for the most populous Brazilian State, São Paulo, severely impacted by COVID-19. Ground-based air quality data (PM10, PM2.5, CO, SO2, NOx, NO2, NO, and O3) were used from 50 automatic air quality monitoring stations to evaluate the changes in concentrations before (January 01 - March 25) and during the partial quarantine (March 16 - June 30). Rainfall, fires, and daily cell phone mobility data were also used as supplementary information to the analyses. The Mann-Whitney U test was used to assess the heterogeneity of the air quality data during and before mobility restrictions. In general, the results demonstrated no substantial improvements in air quality for most of the pollutants when comparing before and during restrictions periods. Besides, when the analyzed period of 2020 is compared with the year 2019, there is no significant air quality improvement in the São Paulo State. However, special attention should be given to the Metropolitan Area of São Paulo (MASP), due to the vast population residing in this area and exposed to air pollution. The region reached an average decrease of 29% in CO, 28% in NOx, 40% in NO, 19% in SO2, 15% in PM2.5, and 8% in PM10 concentrations during the mobility restrictions period compared to the same period in 2019. The only pollutant that showed an increase in concentration was ozone, with a 20% increase compared to 2019 during the mobility restrictions period. Before the mobility restrictions period, the region reached an average decrease of 30% in CO, 39% in NOx, 63% in NO, 12% in SO2, 23% in PM2.5, 18% in PM10, and 16% in O3 concentrations when compared to the same period in 2019. On the other hand, Cubatão, a highly industrialized area, showed statistically significant increases above 20% for most monitored pollutants in both periods of 2020 compared to 2019. This study reinforces that the main driving force of pollutant concentration variability is the dynamics of the atmosphere at its various time scales. An abnormal rainy season, with above average rainfall before the restrictions and below average after it, generated a scenario in which the probable significant reductions in emissions did not substantially affect the concentration of pollutants.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , COVID-19 , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Brasil/epidemiologia , Cidades , Monitoramento Ambiental , Humanos , Pandemias , Material Particulado/análise , Políticas , SARS-CoV-2
4.
Oper Dent ; 43(1): 12-21, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-28976841

RESUMO

OBJECTIVE: The objective of this study was to clinically evaluate repaired posterior amalgam and composite restorations over a 12 year period, investigate the influence of repair in the survival of restorations, and compare their behavior with respect to controls. METHODS: Thirty-four patients, 18 to 80 years of age with 167 restorations, 67 composite resin (RC), and 100 amalgam (AM) restorations, participated. Restorations with localized, marginal, anatomical deficiencies and/or secondary caries, and "clinically judged" suitable for repair or replacement according to US Public Health Service (USPHS) criteria, were randomly assigned to four groups: repair (n=35, 20 AM, 15 RC), replacement (n=43, 21 AM, 22 RC), positive control (n=71, 49 AM, 22 RC), or negative control (n=18, 10 AM, 8 RC). The quality of the restorations was blind scored according to the modified USPHS criteria. Two examiners scored them at initial status (κ=0.74) and after one to five, 10, and 12 years (κ=0.88). Wilcoxon and Mann-Whitney tests provided for comparisons within the same group and between years, respectively. RESULTS: After 12 years, all groups behaved similarly in marginal adaptation, marginal stain, teeth sensitivity, anatomic form, and luster ( p≥0.05). Better behavior in roughness was observed in replaced RC ( p=0.049). CONCLUSIONS: Given that most clinical parameters investigated were similar between all groups during the follow-up, the repair of RC and AM restorations is a good clinical option because it is minimally invasive and can consistently increase the longevity of restorations.


Assuntos
Resinas Compostas/efeitos adversos , Amálgama Dentário/efeitos adversos , Falha de Restauração Dentária , Reparação de Restauração Dentária , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Resinas Compostas/uso terapêutico , Amálgama Dentário/uso terapêutico , Reparação de Restauração Dentária/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Adulto Jovem
5.
Oper Dent ; 42(6): 587-595, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28857709

RESUMO

OBJECTIVES: The aim of this study was to clinically evaluate posterior amalgam and resin composite restorations refurbished over a period of 12 years by investigating the influence of refurbishing on the survival of restorations and comparing their behaviors with respect to controls. METHODS AND MATERIALS: Thirty-four patients were enrolled, ages 18 to 80 years, with 174 restorations, 48 restorations of resin composite (RC), and 126 restorations of amalgam (AM). Restorations with localized defects in anatomy, roughness, luster, or marginal staining that were clinically judged as suitable for refurbishing according to US Public Health Service (USPHS) Ryge criteria were assigned to group A-refurbishing (n=85; 67 AM, 18 RC)-or group B-control (n=89; 59 AM, 30 RC); the quality of the restorations was evaluated blindly according to the modified USPHS criteria. Two observers conducted evaluations at the initial state (k=0.74) and after one to five, 10, and 12 years (k=0.88). Wilcoxon, Friedman, and Mantel-Cox tests were performed to compare the groups, respectively. RESULTS: After 12 years, both groups experienced a similar decline, except for an evidently better performance in marginal adaptation in RC control (p=0.043) and in anatomy in AM refurbished (p=0.032). CONCLUSIONS: After 12 years, no difference was found in the clinical condition and longevity of the refurbished restorations compared to the control group.


Assuntos
Resinas Compostas/uso terapêutico , Amálgama Dentário/uso terapêutico , Restauração Dentária Permanente/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Falha de Restauração Dentária/estatística & dados numéricos , Reparação de Restauração Dentária/métodos , Reparação de Restauração Dentária/estatística & dados numéricos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
6.
Int. j. morphol ; 34(3): 1117-1122, Sept. 2016. ilus
Artigo em Inglês | LILACS | ID: biblio-828995

RESUMO

The surgical treatment of breast cancer has been enhanced throughout the years in order to offer oncologically safer and more effective results with lower esthetic impact and fewer sequelae. The lymphedema of the upper limb is still an iatrogenic result of great incidence and morbidity after this treatment. A possible existence of independent breast and upper limb lymphatic pathways has become the issue of many researchers willing to minimize its occurrence. This review aims to compare the lymphatic pathways in the axilla described by traditional anatomy books and recently published articles about Axillary Reverse Mapping (ARM). With this purpose, a comparative table was made with the descriptions found in books and articles, a statistic table of the data collected, a flowchart of anastomoses among nodes and an analytical drawing of the most statistically mentioned drained areas. It was observed that there is great variability in the descriptions of drainage and anastomoses among the lymph nodes in the references used, so there should be a consensus of a universal description which also assembles possible anatomical variations. Furthermore, the findings brought about by recent studies show possible anastomoses among pathways and lymph nodes, however they have not been taken into consideration when ARM was initially proposed. Therefore, the axillary resection with the preservation of the posterior and lateral axillary lymph nodes is theoretically possible to avoid lymphedema of the upper limb, but the development of an updated universal description that involves all possible anatomical variations will provide a safer and more effective treatment.


El tratamiento quirúrgico del cáncer de mama ha mejorado a lo largo de los años con el fin de ofrecer resultados oncológicamente más seguros y eficaces con menor impacto estético y menos secuelas. El linfedema del miembro superior es todavía un resultado iatrogénico de gran incidencia y morbilidad después de este tratamiento. La posible existencia de vías linfáticas de mama y de los miembros superiores independientes se ha convertido en un tema central de muchas investigaciones para lograr minimizar su ocurrencia. Esta revisión tiene como objetivo comparar las vías linfáticas en la axila descritas en los libros de anatomía tradicionales con artículos recientemente publicados sobre Mapeo Reverso Axilar (MRA). Con este fin, se realizó un cuadro comparativo con las descripciones y un diagrama de flujo de las anastomosis entre los nodos, además de un dibujo analítico de las áreas drenadas estadísticamente más mencionadas. Se observó que existe una gran variabilidad en las descripciones sobre el drenaje y las anastomosis entre los nodos linfáticos, por lo que la descripción universal no debería ser considerada un consenso debido a que también presenta posibles variaciones anatómicas. Por otra parte, los resultados producidos por los estudios recientes muestran posibles anastomosis entre las vías y los nodos linfáticos, sin embargo, no se han tomado en consideración cuando se propuso inicialmente el MRA. Por lo tanto, la resección axilar con la preservación de la parte posterior y los nodos linfáticos axilares laterales es teóricamente posible para evitar el linfedema del miembro superior, pero el desarrollo de una descripción universal actualizada, que incluya todas las posibles variaciones anatómicas, proporcionará un tratamiento más seguro y eficaz.


Assuntos
Humanos , Feminino , Mama/anatomia & histologia , Linfonodos/anatomia & histologia , Vasos Linfáticos/anatomia & histologia , Linfedema/prevenção & controle , Extremidade Superior/anatomia & histologia , Axila , Neoplasias da Mama/complicações , Neoplasias da Mama/cirurgia , Drenagem , Linfedema/etiologia , Complicações Pós-Operatórias/prevenção & controle
7.
Oper Dent ; 40(1): 34-43, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25100406

RESUMO

The aim of this prospective, blind, and randomized clinical trial was to assess the effectiveness of repair of localized clinical defects in amalgam restorations that were initially scheduled for replacement. A cohort of 20 patients with 40 (Class I and Class II) amalgam restorations that presented one or more clinical features that deviated from the ideal (Bravo or Charlie) according to US Public Health Service criteria, were randomly assigned to either the repair or the replacement group-A: repair, n = 19; and B: replacement, n = 21. Two examiners who had calibration expertise evaluated the restorations at baseline and 10 years after according to seven parameters: marginal occlusal adaptation, anatomic form, surface roughness, marginal staining, contact, secondary caries, and luster. After 10 years, 30 restorations (75%) were evaluated (Group A: n = 17; Group B: n = 13). Repaired and replaced amalgam restorations showed similar survival outcomes regarding marginal defects and secondary caries in patients with low and medium caries risk, and most of the restorations were considered clinically acceptable after 10 years. Repair treatment increased the potential for tooth longevity, using a minimally interventional procedure. All restorations trend to downgrade over time.


Assuntos
Amálgama Dentário/uso terapêutico , Reparação de Restauração Dentária/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Falha de Restauração Dentária , Restauração Dentária Permanente/efeitos adversos , Restauração Dentária Permanente/métodos , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Método Simples-Cego , Resultado do Tratamento , Adulto Jovem
8.
J Dent ; 43(2): 279-86, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24907560

RESUMO

OBJECTIVES: The aim of this double-blind clinical trial was to assess the longevity of repairs to localized clinical defects in composite resin restorations that were initially planned to be treated with a restoration replacement. METHODS: Twenty-eight patients aged 18-80 years old with 50 composite resin restorations (CR) were recruited. The restorations with localized, marginal, anatomical deficiencies and/or secondary caries adjacent to CR that were "clinically judged" to be suitable for repair or replacement according to the USPHS criteria were randomly assigned to Repair (n=25) or Replacement (n=25) groups, and the quality of the restorations was scored according to the modified USPHS criteria. The restorations were blind and two examiners scored them at baseline (Cohen Kappa agreement score 0.74) and at ten years (Cohen Kappa agreement score 0.87) restorations. Wilcoxon tests were performed for comparisons within the same group (95% CI), and Friedman tests were utilized for multiple comparisons between the different years within each group. RESULTS: Over the decade, the two groups behaved similarly on the parameters of marginal adaptation (MA) (p>0.05), secondary caries (SC) (p>0.05), anatomy (A) (p<0.05), and colour (C) (p>0.05). CONCLUSIONS: Given that the MA, SC, A and C parameters behaved similarly in both groups, the repair of composite resins should be elected when clinically indicated, because it is a minimally invasive treatment that can consistently increase the longevity of restorations. CLINICAL SIGNIFICANCE: The repair of defective composite resins as an alternative treatment to increase their longevity proved to be a safe and effective treatment in the long term.


Assuntos
Resinas Compostas/farmacologia , Restauração Dentária Permanente , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Cor , Adaptação Marginal Dentária , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Adulto Jovem
9.
Lymphology ; 47(2): 82-91, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25282874

RESUMO

Our aim was to compare the responses of physical treatment with or without manual lymphatic drainage (MLD) in lymphedema after breast cancer treatment in a Brazilian population. This was a controlled clinical trial with lymphedema secondary to breast cancer treatment patients that were randomized into either: Group 1 consisting of MLD, skin care, bandaging and remedial exercises; or Group 2 using skin care, bandaging and remedial exercises. Sixty-six patients were randomized and 9 were excluded during the first phase, resulting in a total of 57 patients eligible for analyzes with 28 in Group 1 and 29 in Group 2. The first phase of treatment had an average duration of 24 days (+/- 12.38) and final volume excess average (VE) between limbs was 494.51 ml, corresponding to 29.18% of the initial volume. Volume reduction was highly significant, independent of the intervention (p < 0.001), and both treatments led to an average of percentage volume excess reduction (PVER) of 15.02%. Patients with incomplete range of motion and lymphatic-related fibrotic tissues showed a statistically significant reduction in the percentage of volume excess (p = 0.010; p = 0.009). The presence of arm paresthesia was associated with the lowest therapeutic response (p = 0.024). Both treatment groups demonstrated absolute and relative reductions of excess limb volume, and the addition of MLD did not significantly increase the therapeutic response in women with lymphedema after breast cancer.


Assuntos
Neoplasias da Mama/cirurgia , Linfedema/terapia , Modalidades de Fisioterapia , Adulto , Idoso , Braço , Bandagens , Drenagem , Feminino , Humanos , Linfedema/etiologia , Linfedema/patologia , Pessoa de Meia-Idade , Satisfação do Paciente , Amplitude de Movimento Articular , Resultado do Tratamento
10.
Int J Oral Maxillofac Surg ; 43(11): 1313-8, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25088528

RESUMO

Adenoid cystic carcinoma (ACC) is the most common malignant salivary gland tumour of the maxillary sinus. The present study describes 24 cases seen over a period of 10 years at the Brazilian National Cancer Institute. Socio-demographic, clinical, pathological, and follow-up data were retrieved from the medical files for the period 1997-2006. The mean age of the patients was 51.1 years. Twenty-one (87.5%) presented advanced tumours. The main signs and symptoms found were a tumour mass (87.5%), pain (50%), nasal obstruction (25%), and epistaxis (20.8%). Most cases (62.5%) were treated with surgery and radiation therapy. Follow-up data showed two patients (8.3%) with residual disease, local recurrences in four (16.7%) patients, and distant metastasis in five (20.8%). The overall 5- and 10-year survival rates were 72.61% and 62.11%, respectively. Maxillary sinus ACC has an aggressive but indolent behaviour, typically presenting at an advanced T stage that reflects a poor prognosis for patients.


Assuntos
Carcinoma Adenoide Cístico/patologia , Seio Maxilar/patologia , Neoplasias dos Seios Paranasais/patologia , Neoplasias das Glândulas Salivares/patologia , Adulto , Idoso , Brasil , Carcinoma Adenoide Cístico/terapia , Terapia Combinada , Diagnóstico por Imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Recidiva Local de Neoplasia/terapia , Estadiamento de Neoplasias , Neoplasias dos Seios Paranasais/terapia , Fatores de Risco , Neoplasias das Glândulas Salivares/terapia , Taxa de Sobrevida
11.
J Chem Phys ; 141(7): 074709, 2014 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-25149808

RESUMO

We study the model proposed by Ziff, Gulari, and Barshad to mimic the oxidation of carbon monoxide (CO) in the presence of fixed impurities distributed over the catalytic surface. Our focus is on the continuous phase transition between the active phase, where occurs the production of carbon dioxide (CO2), and the inactive phase, where all the non inert sites become filled with oxygen molecules. We employ Monte Carlo simulations to calculate the different ratios between moments of the order parameter at the critical point, as well as, we determine the critical exponents ß and ν⊥ as a function of the concentration of impurities. We show that the presence of impurities over the catalytic surface changes the critical behavior of the system. The critical exponents depend on the concentration of impurities and the model does not belong to the directed percolation universality class.


Assuntos
Monóxido de Carbono/química , Método de Monte Carlo , Adsorção , Catálise , Oxirredução , Oxigênio/química , Transição de Fase
12.
J Chem Phys ; 136(16): 164502, 2012 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-22559491

RESUMO

We study a model of heterogeneous catalysis with competitive reactions between two monomers A and B. We assume that reactions are dependent on temperature and follow an anti-Arrhenius mechanism. In this model, a monomer A can react with a nearest neighbor monomer A or B, however, reactions between monomers of type B are not allowed. We assume attractive interactions between nearest neighbor monomers as well as between monomers and the catalyst. Through mean-field calculations, at the level of site and pair approximations, and extensive Monte Carlo simulations, we determine the phase diagram of the model in the plane y(A) versus temperature, where y(A) is the probability that a monomer A reaches the catalyst. The model exhibits absorbing and active phases separated by lines of continuous phase transitions. We calculate the static, dynamic, and spreading exponents of the model, and despite the absorbing state be represented by many different microscopic configurations, the model belongs to the directed percolation universality class in two dimensions. Both reaction mechanisms, Arrhenius and anti-Arrhenius, give the same set of critical exponents and do not change the nature of the universality class of the catalytic models.

13.
Oper Dent ; 37(1): 80-6, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-21942240

RESUMO

OBJECTIVES: This study evaluated the bond strength of luting systems for bonding glass fiber posts to root canal dentin. The hypothesis tested was that there are no differences in bond strength of glass fiber posts luted with different cement systems. METHODS: Forty bovine incisors were randomly assigned to five different resin cement groups (n=8). After endodontic treatment and crown removal, translucent glass fiber posts were bonded into the root canal using five different luting protocols (self-cured cement and etch-and-rinse adhesive system; dual-cured cement and etch-and-rinse adhesive system; self-cured cement and self-etch adhesive system; dual-cured cement and self-etch adhesive system; and dual-cured self-adhesive cement). Push-out bond strength was evaluated at three different radicular levels: cervical, middle, and apical. The interface between resinous cement and the post was observed using a stereoscopic microscope. RESULTS: Analysis of variance showed a statistically significant difference among the cements (p<0.05) and the root canal thirds (p<0.05). The self-adhesive resinous cement had lower values of retention. CONCLUSIONS: The resin cements used with etch-and-rinse and self-etch adhesive systems seem to be adequate for glass fiber post cementation.


Assuntos
Resinas Compostas/química , Colagem Dentária , Materiais Dentários/química , Cavidade Pulpar/ultraestrutura , Dentina/ultraestrutura , Vidro/química , Técnica para Retentor Intrarradicular/instrumentação , Cimentos de Resina/química , Condicionamento Ácido do Dente/métodos , Animais , Bis-Fenol A-Glicidil Metacrilato/química , Compostos de Boro/química , Bovinos , Cimentação/métodos , Retenção em Prótese Dentária , Adesivos Dentinários/química , Metacrilatos/química , Metilmetacrilatos/química , Ácidos Fosfóricos/química , Polietilenoglicóis/química , Ácidos Polimetacrílicos/química , Distribuição Aleatória , Autocura de Resinas Dentárias/métodos , Estresse Mecânico , Propriedades de Superfície , Fatores de Tempo , Ápice Dentário/ultraestrutura , Água/química
15.
Phys Rev E Stat Nonlin Soft Matter Phys ; 83(3 Pt 1): 031108, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21517455

RESUMO

We determine the critical behavior of a reactive model with many absorbing configurations. Monomers A and B land on the sites of a linear lattice and can react depending on the state of their nearest-neighbor sites. The probability of a reaction depends on temperature of the catalyst as well as on the energy coupling between pairs of nearest-neighbor monomers. We employ Monte Carlo simulations to calculate the moments of the order parameter of the model as a function of temperature. Some ratios between pairs of moments are independent of temperature and are in the same universality class of the contact process. We also find the dynamical critical exponents of the model and we show that they are in the directed percolation universality class whatever the values of temperature.

16.
Phys Rev E Stat Nonlin Soft Matter Phys ; 81(2 Pt 1): 021114, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20365537

RESUMO

We study a competitive reaction model between two monomers A and B on a linear lattice. We assume that monomer A can react with a nearest-neighbor monomer A or B , but reactions between monomers of type B are prohibited. We include in our model lateral interactions between monomers as well as the effects of temperature of the catalyst. The model is considered in the adsorption controlled limit, where the reaction rate is infinitely larger than the adsorption rate of the monomers. We employ site and pair mean-field approximations as well as static Monte Carlo simulations. We determine the phase diagram of the model in the plane y_{A} versus temperature, where y_{A} is the probability that a monomer of the type A arrives at the surface. This phase diagram shows regions of active and absorbing states separated by a line of continuous phase transitions. Despite the absorbing state of the model to be strongly dependent on temperature, we show that the static critical exponents of the model belong to the same universality class of the directed percolation.

18.
Environ Pollut ; 121(1): 63-73, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12475062

RESUMO

Numerical modeling of scavenging processes has been compared with data obtained for rainwater and aerosol chemistry at Serra do Navio, in the state of Amapá in the Brazilian Amazon region. Sulfate, nitrate and ammonium concentrations were determined in rainwater samples collected from May 1995 until June 1997. The levels of these same chemicals were also determined in aerosols for the same period and region. Scavenging processes have been evaluated on a rainfall event basis, via numerical modeling, in order to simulate the rainwater concentrations and compare them with the observed data. RAMS (Regional Atmospheric Modeling System) was used to simulate cloud structures. A model of below-cloud scavenging was evaluated, as well. The determinations made from the results of the scavenging model are the following: a) aerosol vertical profiles are quite important to rainwater concentrations; b) modeled sulfate in rainwater is a better fit to the observed data values than ammonium and nitrate; c) the obtained sulfate aerosol concentrations samples are similar to ones found in the literature, although the sulfate concentrations in rainwater are much lower than other studies in the literature; d) the in-cloud scavenging process dominates, e) our modeled results, using an input gas vertical profile extracted from the ABLE2B experimental data set, present a smaller ratio between gas and aerosol scavenging than found in other studies in the literature, other studies may have had larger rainfall times, which increase the importance of gas phase scavenging.


Assuntos
Simulação por Computador , Modelos Químicos , Chuva , Poluentes Químicos da Água/análise , Aerossóis , Poluentes Atmosféricos/análise , Brasil , Resíduos Industriais , Nitratos/análise , Compostos de Amônio Quaternário/análise , Sulfatos/análise
19.
Environ Sci Technol ; 35(15): 3071-81, 2001 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-11505981

RESUMO

Winter atmospheric measurements of gaseous lower carbonyl and carboxylic acids were carried out simultaneously (in 1999) at two distinct urban sites located in the city of São Paulo, Brazil. The greater metropolitan area of São Paulo is the largest industrialized region of Latin America and has a highly polluted atmosphere. It has an unconventional mix of vehicle types in that a variety of gasoline blends, including oxygenated ones, are used. Mixing ratios of formic and acetic acids ranged, respectively, from 0.6 to 19.4 and from 0.1 to 10.6 ppbv in one of the sites studied and from 1.4 to 18.4 and from 0.4 to 6.7 ppbv in the other site. High values of formic to acetic ratios were found, especially in the latter site (average = 4.3), suggesting that photochemical production was the predominant source of the formic and acetic acid during the afternoon. Differing from the acids, levels of carbonyls were similar at both sites. Higher average mixing ratios of acetaldehyde and formaldehyde were found in the morning (18.9 and 17.2 ppbv) and gradually decreased from midday (9.5 and 11.8 ppbv) to evening (7.2 and 10.2 ppbv). In the morning, vehicular direct emission seemed to be the main primary source of formaldehyde and acetaldehyde, whereas at midday and evening these compounds appeared to be mainly formed by photochemistry. Secondary photochemical production of organic acids and aldehydes (rather than primary emissions from vehicles) was shown to be more important in São Paulo's atmosphere from midday to evening, particularly on days with strong solar radiation.


Assuntos
Poluentes Atmosféricos/análise , Ácidos Carboxílicos/análise , Emissões de Veículos/análise , Aldeídos/análise , Brasil , Cidades , Desinfetantes/análise , Monitoramento Ambiental , Formaldeído/análise , Fotoquímica , Raios Ultravioleta
20.
Rev. bras. farmacogn ; 11(1): 13-19, 2001. ilus
Artigo em Inglês | LILACS | ID: lil-528791

RESUMO

Bothrops venoms are composed by several protein fractions. Among these fractions there are myotoxins which induce an important muscle lesion. The purification of this component involves some steps, although providing a pure material, is time consuming. In the present study, we describe a quick method for myotoxin fraction isolation from the venom of Bolhrops nsuwiedi using one-step high performance liquid chromatography (HPLC). The complete procedure took 30 min. The pur6+y of the two myotoxic fractions isolated was assessed by SDS-PAGE. Upon i.m. injection into rat tibialis anterior, both toxins induced early morphological changes, indicating that the plasma membrane was the first cellular structure affected. Afterwards, the lesion was typically myonecrotic and inflammatory infiltrate was present.


Os venenos de Bolhrops são compostos por várias frações protéicas. Dentre elas, as miotoxinas induzem lesões musculares importantes. A purificação deste componente envolve várias etapas e, embora forneça frações puras, é muito trabalhosa. Neste trabalho foi descrito um método rápido para o isolamento da fração miotóxica do veneno de Bothrops neuwiedi (jararaca pintada), utilizando-se uma etapa única de purificação por Cromatografia Liquida de Alta Eficiência (CLAE). O procedimento completo demorou apenas 30 min. Foram isoladas duas frações com atividade miotóxica, cuja pureza foi verificada por eletroforese em gel de poliacrilamida-SDS. A injeção intramuscular no músculo tibial anterior de ratos induziu alterações morfológicas precoces, indicando que a membrana plasmática foi a primeira estrutura celular afetada pela fração miotóxica. A lesão muscular obtida foi tipicamente mionecrótica e foi observado infiltrado inflamatório.

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