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1.
Langmuir ; 40(22): 11371-11380, 2024 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-38758366

RESUMO

The apparent tortuosity due to adsorption of diffusing tracers in a porous material is determined by a scaling approach and is used to analyze recent data on LiCl and alkane diffusion in mesoporous silica. The slope of the adsorption isotherm at small loadings is written as ß = qA/qG, where qA is the adsorption-desorption ratio and qG = ϵ/(as) - 1 is a geometrical factor depending on the range a of the tracer-wall interaction, the porosity ϵ, and the specific surface area s. The adsorption leads to a decrease of effective diffusion coefficient, which is quantified by multiplying the geometrical tortuosity factor τgeom by an apparent tortuosity factor τapp. In wide pores or when the adsorption barrier is high, τapp = ß + 1, as obtained in previous works, but in narrow pores there is an additional contribution from frequent adsorption-desorption transitions. These results are obtained in media with parallel pores of constant cross sections, where the ratio between the effective pore width ϵ/s and the actual width is ≈0.25. Applications to mesoporous silica samples are justified by the small deviations from this ideal ratio. In the analysis of alkane self-diffusion data, the fractions of adsorbed molecules predicted in a recent theoretical work are used to estimate τgeom of the silica samples, which is ≫1 only in the sample with the narrowest pores (nominal 3 nm). The application of the model to Li+ ion diffusion leads to similar values of τgeom and to a difference of energy barriers of desorption and adsorption for those ions of ∼0.06 eV. Comparatively, alkane self-diffusion provides the correct order of magnitude of τgeom, with adsorption playing a less important role, whereas adsorption effects on Li+ diffusion are much more important.

3.
Mar Pollut Bull ; 197: 115682, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37951119

RESUMO

The current case study focuses on the Environmental Sensitivity Index (ESI) mapping of Guanabara Bay, Rio de Janeiro, Brazil - a region at risk from petroleum sector pollution. By mapping 981.5 km of coastline and classifying it in 10 oil sensitivity indices, we integrated biotic resources, socioeconomic attributes, and geoenvironmental diversity into a georeferenced database. Results reveal a high oil sensitivity of the bay, with approximately 89 % of the mapped coast scoring ESI 8 and ESI 10. These scores comprise, respectively, estuarine and solid substrate habitats that are sheltered from wave action. Notably, numerous manufacturing and oil handling plants, along with intensive urbanization, also contribute to the bay's oil sensitivity. Additionally, the rich biotic diversity in the study area, particularly in protected areas housing 79 conservation units, further amplifies its environmental vulnerability. This study aims to serve as a reference for detailed ESI mapping of coastal areas in tropical rainy zones with significant environmental diversity, industrial development, and a dense population.


Assuntos
Poluição por Petróleo , Brasil , Monitoramento Ambiental/métodos , Ecossistema , Bases de Dados Factuais
4.
Environ Monit Assess ; 195(12): 1449, 2023 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-37945782

RESUMO

The oil spill environmental sensitivity index is a key tool for preventing and dealing with environmental disasters caused by oil spills. This study aims to review the available literature on the subject and highlight the importance of methodological advances to improve how the index is applied in continental areas, especially in regions crossed by pipelines. Most current mapping techniques focus on coastal areas and fail to consider the stretches of land that are vulnerable to geodynamic natural disasters. In this context, the need to implement environmental sensitivity indices specific for pipelines has become urgent. This study also presents an overview of the main accidents around the world and a detailed analysis of the history of Brazilian disasters related to oil spills along continental stretches, with a focus on pipelines and natural disasters. In addition, this work highlights the importance of carrying out new research in mountainous areas of Brazil and is aimed at preventing Natechs (natural hazard triggering technological disasters) and improving contingency plans. As a result, several pathways have been identified, which involves the necessity of resolving gaps in terrestrial environmental sensitivity mapping methodologies, particularly as applied to pipelines. Furthermore, solutions must be capable of integrating terrestrial, fluvial, coastal, and maritime environmental sensitivity mapping techniques. Moreover, the need to implement dynamic risk monitoring systems in real time is critical to help manage such a complex problem.


Assuntos
Desastres , Poluição por Petróleo , Monitoramento Ambiental , Desastres/prevenção & controle , Brasil
5.
Contrib Nephrol ; 200: 107-117, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37263243

RESUMO

A strong rationale supports the development of adsorption-based extracorporeal blood purification in conditions such as sepsis, acute kidney disease, uremia, and acute liver failure. The retention of compounds as a consequence of acute or chronic organ dysfunction might have detrimental effects. When a causative effect of an accumulated compound in a pathogenic condition is demonstrated, a rationale for the removal of this solute is also established. Adsorption is a mass transfer mechanism in which a solute chemically interacts with the surface of a solid structure (sorbent) and is removed from its solvent (i.e., blood or plasma). Traditional extracorporeal blood purification techniques utilize semipermeable membranes and depend mainly on diffusion and convection as mechanisms of mass transfer. Protein-bound solutes and water-soluble compounds with molecular weight above 25 kDa are scantly removed by either diffusive or convective clearances. In contrast, recently developed resins have demonstrated safety aligned with notable adsorptive capability, which enables the extraction of endotoxins, inflammatory mediators, and uremic toxins. The understanding of the kinetics of these elements and the improvement in patient selection are key factors to propel exploratory and confirmatory trials that ultimately will lead to the expected changes in clinical practice.


Assuntos
Sepse , Uremia , Humanos , Adsorção , Uremia/terapia , Água , Endotoxinas , Diálise Renal/métodos
6.
Landslides ; 20(3): 511-529, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36530578

RESUMO

This study aims at providing an overview of the socioeconomic consequences that debris-flow events have caused in Brazil, positioning the country in the international scenario and identifying areas where targeted actions are necessary. The analysis is conducted by calculating the debris-flow mortality rate (MR) and by using the so-called F-N plots (frequency of events that have caused N or more fatalities vs. the number of fatalities), based on a compilation of debris-flow-related disasters from 1920 to 2021. In total, 45 debris-flow events were documented in the considered period, responsible for 5771 fatalities and more than 5.5 billion USD in economic losses. The Serra do Mar Mountain Range is the main site of reported debris-flow occurrences (64.5%), followed by Serra da Mantiqueira (13.3%), and Serra Geral (13.3%). Southeast Brazil (SEB) is the region most affected by debris-flow events, due to the highest population density and the development of several cities in hilly areas, such as Petrópolis (Rio de Janeiro state) and Cubatão (São Paulo state). The debris-flow MR of SEB is higher than any other region in Brazil, pushing the national debris-flow MR upwards, and the F-N curve of SEB consolidates the region as the one with the highest risk to the phenomenon, indicating a higher probability of fatal events. The F-N plots further show that debris-flow events in Brazil represent a higher societal risk than in countries such as China, Japan and Italy. While there are differences in country size and the scale effect should be considered, these results highlight the urgent need for investments in disaster prevention and preparedness programs. Supplementary Information: The online version contains supplementary material available at 10.1007/s10346-022-01984-7.

7.
Phys Rev E ; 108(6-1): 064802, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38243503

RESUMO

We perform kinetic Monte Carlo simulations of film growth in simple cubic lattices with solid-on-solid conditions, Ehrlich-Schwoebel (ES) barriers at step edges, and a kinetic barrier related to the hidden off-plane diffusion at multilayer steps. Broad ranges of the diffusion-to-deposition ratio R, detachment probability per lateral neighbor, ε, and monolayer step crossing probability P=exp[-E_{ES}/(k_{B}T)] are studied. Without the ES barrier, four possible scaling regimes are shown as the coverage θ increases: nearly layer-by-layer growth with damped roughness oscillations; kinetic roughening in the Villain-Lai-Das Sarma (VLDS) universality class when the roughness is W∼1 (in lattice units); unstable roughening with mound nucleation and growth, where slopes of logW×logθ plots reach values larger than 0.5; and asymptotic statistical growth with W=θ^{1/2} solely due to the kinetic barrier at multilayer steps. If the ES barrier is present, the layer-by-layer growth crosses over directly to the unstable regime, with no transient VLDS scaling. However, in simulations up to θ=10^{4} (typical of films with a few micrometers), low temperatures (small R, Îµ, or P) may suppress the two or three initial regimes, while high temperatures and P∼1 produce smooth surfaces at all thicknesses. These crossovers help to explain proposals of nonuniversal exponents in previous works. We define a smooth film thickness θ_{c} where W=1 and show that VLDS scaling at that point indicates negligible ES barriers, while rapidly increasing roughness indicates a small ES barrier (E_{ES}∼k_{B}T). θ_{c} scales as ∼exp(const×P^{2/3}) if the other parameters are kept fixed, which represents a high sensitivity on the ES barrier. The analysis of recent experimental data in the light of our results distinguishes cases where E_{ES}/(k_{B}T) is negligible, ∼1, or ≪1.

8.
An Acad Bras Cienc ; 94(suppl 4): e20210869, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36477819

RESUMO

This work aims to carry out an analysis of the evolution of the civil defense protection policy in Brazil, as well as to present an overview of research related to public policies on natural disasters in the world. The research was developed by documentary analysis of Brazilian policies on the protection of civil defense and bibliometric analysis of the global data. The evolution of public policy on natural disasters in Brazil was divided into four different moments: a) military civil defense (1942-1946), b) disaster assistance policy (1967-1988), c) Civil Defense system in construction (1988-2005), and d) consolidation of the civil defense system (2005- to the present). The structuring of public policy reflected in 4 different stages in relation to the recording of information about disasters. Bibliometric analysis showed that the first works related to public civil defense policies in the world appeared only in 1980, and are mainly concentrated in the United States, which accounts for 42.56% of the works, while Brazil is the 6th country with 3.76% of global searches. Thus, it is possible to conclude that public policies and databases have a recent evolution both in Brazil and in the world, especially in developing countries.


Assuntos
Desastres Naturais , Política Pública , Brasil
9.
Phys Chem Chem Phys ; 24(45): 27856-27865, 2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36367016

RESUMO

We study a thin-film electrodeposition model that represents the relaxation of the deposited material by adatom diffusion on quenched crystal topographies and considers simple mechanisms of cation flux in the electrolyte. The results of numerical simulations with collimated flux and a rapid cation reduction in contact with the deposit relate the surface roughness and the adatom hop numbers with two model parameters. A comparison with the results of a collective diffusion model for vapor deposition shows differences in the surface morphologies but similarities in scaling relations, which suggest thermally activated (Arrhenius) forms for the parameters of the electrodeposition model and relate one of them to the applied current. Simulations with purely diffusive cation flux and possible pore formation in simple cubic lattices show the growth of self-organized structures with leaf shapes (dendrites) above a compact layer that covers the flat electrode. The thickness of this layer and the average dendrite size also obey scaling relations in terms of the model parameters, which predict that both sizes decrease with the applied current, in agreement with recent experimental studies. Under all flux conditions, an increase in adatom diffusivity with temperature implies an increase in the average sizes of low-energy surface configurations, independently of their particular shapes. Finally, we note that a previously proposed model for electrodeposition produced similar morphologies, but the quantitative relations for the characteristic sizes differ from those of the present model, which also advances with a consistent interpretation of temperature effects.

10.
An Acad Bras Cienc ; 94(suppl 4): e20210946, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36449859

RESUMO

The Environmental Sensitivity Index (ESI) for oil spills was developed to assist coordinators to evaluate oil spill impact along shorelines and also to coordinate the allocation of resources during and after the incident, aiming to reduce environmental damage and consequences. Recently, Remotely Piloted Aerial Systems (RPAS) are being used in a wide range of areas, since they complement traditional remote sensing data (e.g., satellite images) and offer a rapidly, precise, detail and high-resolution images that fit well for environmental studies. Herein, the use of high-resolution RPAS images for ESI analysis of rocky shores in the Brazilian territory was performed. Using RPAS images, with their higher-resolution compared with ArcGIS Pro Basemap satellite images, increased the detailed of ESI analysis for oil spills, increasing the number of regions in the rocky shore that are more sensitive to oil spills. The RPAS images were able to decrease the number of areas that were less sensitive to oil spills, and increase areas that are more sensitive to oil spills. This increase is important, since they were not detected in the ESI analysis using conventional ArcGIS Pro Basemap satellite images. The RPAS images permit to delineate precisely rocky shores, improving ESI interpretation in rocky shores.


Assuntos
Poluição por Petróleo , Brasil
11.
ACS Appl Mater Interfaces ; 14(43): 49362-49374, 2022 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-36281976

RESUMO

During silver electrodeposition on Au nanoparticle (NP)-covered highly oriented pyrolitic graphite, a transition from an initial growth of microsized particles to the growth of dendrites with pine tree shape (nanotrees) is observed, which is an advancement for material growth with hierarchical surface roughness. Using kinetic Monte Carlo simulations of an electrodeposition model, those results are explained by the interplay of diffusive cation flux in the electrolyte and relaxation of adsorbed atoms by diffusion on quenched crystal surfaces. First, simulations on NP-patterned substrates show the initial growth of faceted silver particles, followed by the growth of nanotrees with shapes similar to the experiments. Next, simulations on electrodes with large prebuilt particles explain the preferential nanotree growth at corners and edges as a tip effect. Simulations on wide flat electrodes relate the nanotree width with two model parameters describing surface diffusion of silver atoms: maximal number of random hops (G) and probability of hop per neighbor (P). Finally, simulations with small electrode seeds confirm the transition from initially compact particles to the nucleation of nanotrees and provide estimates of the transition sizes as a function of those parameters. The simulated compact and dendritic deposits show dominant (111) surface orientation, as observed in experiments. Extrapolations of simulation results to match microparticle and nanotree sizes lead to G = 4 × 1011 and P = 0.03, suggesting to interpret those sizes as diffusion lengths on the growing surfaces and giving diffusion coefficients 2 to 3 × 10-13 m2/s for deposited silver atoms. These results may motivate studies to relate diffusion coefficients with atomic-scale interactions.

12.
Can J Kidney Health Dis ; 8: 20543581211054736, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34777842

RESUMO

RATIONALE: Protocols for regional citrate anticoagulation with the hypertonic 4% trisodium citrate solution have been recently described as an anticoagulation strategy during membrane therapeutic plasma exchange (mTPE). The effect of citrate in the patient's systemic hemostasis is negligible, thus regional citrate anticoagulation application is advantageous in circumstances in which heparin-based protocols are deemed unsafe for patients with a high risk of bleeding. The downsides of using hypertonic citrate solutions are mainly hypocalcemia and hypernatremia that ultimately can cause adverse clinical events. PRESENTING CONCERNS OF THE PATIENT: (1) A 57-year-old Caucasian female with a history of active vaginal bleeding secondary to endometrial hyperplasia. She had a history of antiphospholipid syndrome, and systemic lupus erythematosus with marked refractory autoimmune thrombocytopenia. Her platelet count was persistently below 4,000/mm3 even after different immunosuppressive regimens and daily platelet transfusions. (1) A 70-year-old Caucasian female was hospitalized presenting acute kidney injury stage 3 due to rapidly progressive antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, however without the need for renal replacement therapy. At admission, serum creatinine (sCr) was 3.56 mg/dL (normal range: 0.53-1.00 mg/dL). Her baseline sCr was 0.8 mg/dL obtained 6 months earlier. Chest tomography revealed bilateral masses compatible with granulomatous lesions and no signs of alveolar bleeding. Since severe cases of ANCA vasculitis involving the lungs may evolve with alveolar hemorrhage, heparin was avoided. DIAGNOSES: (1) Systemic lupus erythematosus-associated autoimmune thrombocytopenia and (2) ANCA-associated vasculitis with kidney and lung involvement. INTERVENTIONS: Herein, we describe a case series of 12 consecutive mTPE treatments in 2 different patients using regional 4% trisodium citrate anticoagulation. OUTCOMES: All the sessions were uneventful, presented only minor electrolyte imbalances, and were effectively completed without early interruptions due to clotting of the plasmafilter. TEACHING POINTS: In our 2 cases, extracorporeal regional citrate anticoagulation was successful in optimizing plasmafilter patency without bleeding events in 2 high-risk patients using established protocols for the citrate and calcium infusions.


FONDEMENT: Les protocoles d'anticoagulation régionale avec une solution hypertonique à 4 % de citrate trisodique ont récemment été décrits comme stratégie d'anticoagulation pendant les séances d'échange plasmatique par filtration (mTPE ­ membrane therapeutic plasma exchange). L'effet du citrate étant négligeable sur l'hémostase systémique du patient, l'anticoagulation régionale au citrate s'avère avantageuse dans les cas où les protocoles avec l'héparine sont jugés dangereux pour les patients dont le risque d'hémorragie est élevé. Les inconvénients liés aux solutions hypertoniques de citrate sont principalement l'hypocalcémie et l'hypernatrémie, lesquelles peuvent éventuellement entraîner des effets indésirables sur le plan clinique. PRÉSENTATION DES CAS: a) Une femme de race blanche âgée de 57 ans qui présentait des saignements vaginaux actifs en raison d'une hyperplasie de l'endomètre. La patiente avait des antécédents de syndrome antiphospholipide et de lupus érythémateux disséminé avec thrombopénie autoimmune réfractaire marquée. Sa numération plaquettaire demeurait invariablement inférieure à 4 000/mm3 malgré différents traitements immunosuppresseurs et la transfusion quotidienne de plaquettes. b) Une femme de race blanche âgée de 70 ans hospitalisée pour une insuffisance rénale aiguë de stade 3 due à une vascularite à évolution rapide associée aux anticorps cytoplasmiques antineutrophiles (ANCA). La patiente ne nécessitait aucun traitement de remplacement rénal. Son taux de créatinine sérique (SCr) à l'admission était de 3,56 mg/dL (plage normale : 0,53 à 1,00 mg/dL) alors que son taux initial, mesuré 6 mois plus tôt, était de 0,8 mg/dL. Une tomographie thoracique a révélé des masses bilatérales compatibles avec les lésions granulomateuses et l'absence de saignement alvéolaire. L'héparine a été écartée puisque les cas graves de vascularite associée aux ANCA avec atteinte des poumons peuvent évoluer vers une hémorragie alvéolaire. DIAGNOSTICS: a) Thrombocytopénie autoimmune associée à un lupus érythémateux disséminé; b) vascularite associée aux ANCA avec atteinte des reins et des poumons. INTERVENTIONS: Nous décrivons une série de cas impliquant deux patientes ayant subi 12 séances de mTPE consécutives avec un anticoagulant régional à 4 % de citrate trisodique. RÉSULTATS: Toutes les séances se sont déroulées sans incident, seuls des déséquilibres électrolytiques mineurs ont été observés. Toutes les séances ont été réalisées efficacement, sans interruption précoce due au blocage du filtre à plasma. ENSEIGNEMENTS TIRÉS: Dans deux cas qui présentaient un risque élevé d'hémorragie, l'anticoagulation régionale extracorporelle avec citrate, réalisée conformément aux protocoles établis pour les perfusions de citrate et de calcium, a permis d'optimiser la perméabilité du filtre à plasma sans causer d'événement hémorragique.

13.
Arch Microbiol ; 203(8): 4785-4803, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34245357

RESUMO

Twenty years ago, the first members of the genus Burkholderia capable of nodulating and fixing N2 during symbiosis with leguminous plants were reported. The discovery that ß-proteobacteria could nodulate legumes represented a breakthrough event because, for over 100 years, it was thought that all rhizobia belonged exclusively to the α-Proteobacteria class. Over the past 20 years, efforts toward robust characterization of these bacteria with large-scale phylogenomic and taxonomic studies have led to the separation of clinically important and phytopathogenic members of Burkholderia from environmental ones, and the symbiotic nodulating species are now included in the genera Paraburkholderia and Trinickia. Paraburkholderia encompasses the vast majority of ß-rhizobia and has been mostly found in South America and South Africa, presenting greater symbiotic affinity with native members of the families Mimosoideae and Papilionoideae, respectively. Being the main center of Mimosa spp. diversity, Brazil is also known as the center of symbiotic Paraburkholderia diversity. Of the 21 symbiotic Paraburkholderia species described to date, 11 have been isolated in Brazil, and others first isolated in different countries have also been found in this country. Additionally, besides the symbiotic N2-fixation capacity of some of its members, Paraburkholderia is considered rich in other beneficial interactions with plants and can promote growth through several direct and indirect mechanisms. Therefore, these bacteria can be considered biological resources employed as environmentally friendly alternatives that could reduce the agricultural dependence on agrochemical inputs.


Assuntos
Fabaceae , Mimosa , Rhizobium , Brasil , Humanos , Fixação de Nitrogênio , Filogenia , RNA Ribossômico 16S/genética , Rhizobium/genética , Análise de Sequência de DNA , Simbiose
14.
Phys Rev E ; 103(2-1): 022138, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33736020

RESUMO

The infiltration of a solute in a fractal porous medium is usually anomalous, but chemical reactions of the solute and that material may increase the porosity and affect the evolution of the infiltration. We study this problem in two- and three-dimensional lattices with randomly distributed porous sites at the critical percolation thresholds and with a border in contact with a reservoir of an aggressive solute. The solute infiltrates that medium by diffusion and the reactions with the impermeable sites produce new porous sites with a probability r, which is proportional to the ratio of reaction and diffusion rates at the scale of a lattice site. Numerical simulations for r≪1 show initial subdiffusive scaling and long time Fickean scaling of the infiltrated volumes or areas, but with an intermediate regime with time increasing rates of infiltration and reaction. The anomalous exponent of the initial regime agrees with a relation previously applied to infinitely ramified fractals. We develop a scaling approach that explains the subsequent time increase of the infiltration rate, the dependence of this rate on r, and the crossover to the Fickean regime. The exponents of the scaling relations depend on the fractal dimensions of the critical percolation clusters and on the dimensions of random walks in those clusters. The time increase of the reaction rate is also justified by that reasoning. As r decreases, there is an increase in the number of time decades of the intermediate regime, which suggests that the time increasing rates are more likely to be observed is slowly reacting systems.

15.
Hemodial Int ; 25(2): 180-187, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33225535

RESUMO

INTRODUCTION: Medium cutoff (MCO) membranes for hemodialysis (HD) remove more effectively large middle molecules than high-flux (HF) membranes. In patients on in-center short frequent HD regimen (5 sessions per week, 2 hours and 30 minutes per session) the effect of MCO on middle weight uremic toxins has not been elucidated. METHODS: This retrospective study included 15 patients previously performing short frequent HD with HF dialyzer (HF-HD), that were switched to short frequent HD with MCO dialyzer (MCO-HD) for 2 months, and returned to HF-HD. The primary endpoint was the predialysis concentration of α1-acid glycoprotein during the different study phases. Secondary endpoints were predialysis concentration of other middle molecules, albumin, and assessment of the quality of life using the 36-item short-form health survey (SF-36). FINDINGS: During MCO-HD phase there was a reduction in mean ± SD α1-acid glycoprotein concentration (98.71 ± 25.2 vs. 88.6 ± 24.6 mg/dL, P = 0.107), followed by an increment 2 months after returning to HF-HD (89.18 ± 26.12 vs. 97.33 ± 31.29 mg/dL, P = 0.002); however, only the second variation was statistically significant. MCO-HD provided lower median predialysis concentration of prolactin (16 [10.2-25.6] vs. 14.1 [11.7-34.8] ng/mL, P = 0.036). Single-pool Kt/V, standard Kt/V, predialysis ß2-microglobulin, myoglobin, and SF-36 questionnaire remained stable during the first two phases (pre-MCO and MCO). ß2-Microglobulin increased in the post-MCO phase (20.02 ± 8.14 vs. 21.27 ± 7.64 µg/mL, P = 0.000). Mean predialysis concentration of albumin reduced significantly from pre-MCO vs. MCO phases (39.9 ± 3.7 vs. 38.3 ± 3.3 g/L, P = 0.020) and rebounded significantly from MCO vs. post-MCO phases (38.7 ± 3.1 vs. 41.3 ± 3.0 g/L, P = 0.007). DISCUSSION: In this retrospective analysis, short frequent MCO-HD promotes a reduction in prolactin, a middle weight uremic toxin, and trends toward a reduction in α1-acid glycoprotein. No patients developed hypoalbuminemia. These findings are encouraging and deserve investigation in prospective studies.


Assuntos
Hemodiafiltração , Qualidade de Vida , Humanos , Estudos Prospectivos , Diálise Renal , Estudos Retrospectivos
16.
Conexões (Campinas, Online) ; 19: e021002, 2021.
Artigo em Português | LILACS | ID: biblio-1292805

RESUMO

Objetivo: O artigo analisa em paralelo a proficiência motora de crianças e a abordagem de ensino utilizada por um professor de Educação Física do 1º e 5º ano do ensino fundamental de uma escola pública municipal, localizada da região sul do estado de Minas Gerais. Método: Consideramos dois paradigmas para desenvolver a seguinte metodologia: i) teste TGMD-2 para avaliar a proficiência em habilidades motoras fundamentais e inferir a coordenação motora dos escolares; ii) observações sistemáticas e anotações em diário de campo das aulas de Educação Física destes mesmos escolares. Resultados: Observou-se, por exemplo, que foi pouco frequente uma preocupação sistemática com a avaliação no interior da organização do trabalho docente. Conclusões: Concluímos que existe uma queda na proficiência motora dos escolares entre o 1º e 5º ano do ensino fundamental e que elementos básicos da organização do trabalho docente não foram verificados na abordagem de ensino, algo que suscita uma interface entre essas duas variáveis que compõem o cotidiano escolar da disciplina Educação Física.


Objective: The article analyzes in parallel the motor proficiency a children and the teaching approach used by a Physical Education teacher from the 1st and 5th year of elementary school in a municipal public school, located in the southern region of the state of Minas Gerais. Method: We considered two paradigms of the science to develop the following methodology: i) TGMD-2 test to assess proficiency in fundamental motor skills and infer motor coordination of students; ii) systematic observations and notes in the field diary of the Physical Education classes of these same students. Results: It was observed, for example, that there wasn't usually a systematic concern with an evaluation within the teaching work organization. Conclusions: We conclude that there is a drop in the motor proficiency of students between the 1st and 5th year of elementary school and that basic elements of the organization of teaching work were not verified in the teaching approach, something that raises an interface between these two variables that make up the school routine Physical Education.


Objetivo: El artículo analiza en paralelo la competencia motriz de los niños y el enfoque de enseñanza utilizado por un maestro de Educación Física del primer y quinto año de la escuela primaria en una escuela pública municipal, ubicada en la región sur del estado de Minas Gerais. Método: Consideramos dos paradigmas para desarrollar la siguiente metodología: i) prueba TGMD-2 para evaluar el dominio de las habilidades motoras fundamentales e inferir la coordinación motora de los estudiantes; ii) observaciones sistemáticas y notas en el diario de campo de las clases de Educación Física de estos mismos estudiantes. Resultados: Se observó, por ejemplo, que era poco común una preocupación sistemática por la evaluación dentro de la organización del trabajo docente. Conclusiones: Concluimos que hay una caída en la competencia motriz de los estudiantes entre el 1 ° y 5 ° año de la escuela primaria y que los elementos básicos de la organización del trabajo docente no se verificaron en el enfoque de enseñanza, algo que plantea una interfaz entre estas dos variables que conforman la rutina escolar Educación Física.


Assuntos
Humanos , Criança , Educação Física e Treinamento , Criança , Atividade Motora , Destreza Motora , Estudantes , Trabalho , Metodologia como Assunto
17.
Phys Rev E ; 102(4-1): 042802, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33212663

RESUMO

Thin film deposition with particle transport mixing collimated and diffusive components and with barriers for adsorption are studied using numerical simulations and scaling approaches. Biased random walks on lattices are used to model the particle flux and the analogy with advective-diffusive transport is used to define a Peclet number P that represents the effect of the bias towards the substrate. An aggregation probability that relates the rates of adsorption and of the dominant transport mechanism plays the role of a Damkohler number D, where D≲1 is set to describe moderate to low adsorption rates. Very porous deposits with sparse branches are obtained with P≪1, whereas low porosity deposits with large height fluctuations at short scales are obtained with P≫1. For P≳1 in which the field bias is intense, an initial random deposition is followed by Kardar-Parisi-Zhang (KPZ) roughening. As the transport is displaced from those limiting conditions, the interplay of the transport and adsorption mechanisms establishes a condition to produce films with the smoothest surfaces for a constant deposited mass: with low adsorption barriers, a balance of random and collimated flux is required, whereas for high barriers the smoothest surfaces are obtained with P∼D^{1/2}. For intense bias, the roughness is shown to be a power law of P/D, whose exponent depends on the growth exponent ß of the KPZ class, and the porosity has a superuniversal scaling as (P/D)^{-1/3}. We also study a generalized ballistic deposition model with slippery particle aggregation that shows the universality of these relations in growth with dominant collimated flux, particle adsorption at any point of the deposit, and negligible adsorbate diffusion, in contrast with the models where aggregation is restricted to the outer surface.

18.
PLoS One ; 15(11): e0233199, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33147224

RESUMO

INTRODUCTION: IgA nephropathy (IgAN) is the most common primary glomerulopathy worldwide. According to the Oxford Classification, changes in the kidney vascular compartment are not related with worse outcomes. This paper aims to assess the impact of thrombotic microangiopathy (TMA) in the outcomes of Brazilian patients with IgAN. MATERIALS AND METHODS: Analysis of clinical data and kidney biopsy findings from patients with IgAN to assess the impact of TMA on renal outcomes. RESULTS: The majority of the 118 patients included were females (54.3%); mean age of 33 years (25;43); hypertension and hematuria were observed in 67.8% and 89.8%, respectively. Median creatinine: 1.45mg/dL; eGFR: 48.8ml/min/1.73m2; 24-hour proteinuria: 2.01g; low serum C3: 12.5%. Regarding to Oxford Classification: M1: 76.3%; E1: 35.6%; S1: 70.3%; T1/T2: 38.3%; C1/C2: 28.8%. Average follow-up: 65 months. Histologic evidence of TMA were detected in 21 (17.8%) patients and those ones presented more frequently hypertension (100% vs. 61%, p <0.0001), hematuria (100% vs 87.6%, p = 0.0001), worse creatinine levels (3.8 vs. 1.38 mg/dL, p = 0.0001), eGFR (18 vs. 60 ml/min/1.73m2), p = 0.0001), low serum C3 (28.5% vs. 10.4%, p = 0.003), lower hemoglobin levels (10.6 vs. 12.7g/dL, p<0.001) and platelet counts (207,000 vs. 267,000, p = 0.001). Biopsy findings of individuals with TMA revealed only greater proportions of E1 (68% vs. 32%, p = 0.002). Individuals with TMA were followed for less time (7 vs. 65 months, p<0.0001) since they progressed more frequently to chronic kidney disease (CKD) requiring kidney replacement therapy (KRT) (71.4% vs. 21,6%, p<0.0001). Male sex, T1/T2, and TMA were independently associated with progression to CKD-KRT. CONCLUSIONS: In this study patients with TMA had worse clinical manifestations and outcomes. In terms of histologic evidence, E1 distinguished patients with TMA from other patients. Further studies are necessary to analyze the impact of vascular lesions on IgAN prognosis.


Assuntos
Glomerulonefrite por IGA/complicações , Falência Renal Crônica/etiologia , Microangiopatias Trombóticas/patologia , Adulto , Biópsia , Brasil , Creatinina/sangue , Progressão da Doença , Feminino , Taxa de Filtração Glomerular , Glomerulonefrite por IGA/sangue , Humanos , Masculino , Prognóstico , Estudos Retrospectivos , Microangiopatias Trombóticas/complicações
19.
Science ; 370(6515)2020 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-33093082

RESUMO

Pyrite is a ubiquitous iron sulfide mineral that is oxidized by trace oxygen. The mineral has been largely absent from global sediments since the rise in oxygen concentration in Earth's early atmosphere. We analyzed weathering in shale, the most common rock exposed at Earth's surface, with chemical and microscopic analysis. By looking across scales from 10-9 to 102 meters, we determined the factors that control pyrite oxidation. Under the atmosphere today, pyrite oxidation is rate-limited by diffusion of oxygen to the grain surface and regulated by large-scale erosion and clast-scale fracturing. We determined that neither iron- nor sulfur-oxidizing microorganisms control global pyrite weathering fluxes despite their ability to catalyze the reaction. This multiscale picture emphasizes that fracturing and erosion are as important as atmospheric oxygen in limiting pyrite reactivity over Earth's history.

20.
Phys Rev E ; 102(1-1): 012805, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32794924

RESUMO

We study the statistics of the number of executed hops of adatoms at the surface of films grown with the Clarke-Vvedensky (CV) model in simple cubic lattices. The distributions of this number N are determined in films with average thicknesses close to 50 and 100 monolayers for a broad range of values of the diffusion-to-deposition ratio R and of the probability ε that lowers the diffusion coefficient for each lateral neighbor. The mobility of subsurface atoms and the energy barriers for crossing step edges are neglected. Simulations show that the adatoms execute uncorrelated diffusion during the time in which they move on the film surface. In a low temperature regime, typically with Rε≲1, the attachment to lateral neighbors is almost irreversible, the average number of hops scales as 〈N〉∼R^{0.38±0.01}, and the distribution of that number decays approximately as exp[-(N/〈N〉)^{0.80±0.07}]. Similar decay is observed in simulations of random walks in a plane with randomly distributed absorbing traps and the estimated relation between 〈N〉 and the density of terrace steps is similar to that observed in the trapping problem, which provides a conceptual explanation of that regime. As the temperature increases, 〈N〉 crosses over to another regime when Rε^{3.0±0.3}∼1, which indicates high mobility of all adatoms at terrace borders. The distributions P(N) change to simple exponential decays, due to the constant probability for an adatom to become immobile after being covered by a new deposited layer. At higher temperatures, the surfaces become very smooth and 〈N〉∼Rε^{1.85±0.15}, which is explained by an analogy with submonolayer growth. Thus, the statistics of adatom hops on growing film surfaces is related to universal and nonuniversal features of the growth model and with properties of trapping models if the hopping time is limited by the landscape and not by the deposition of other layers.

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