Coagulation equations for aerosol dynamics

Binary coagulation is an important process in aerosol dynamics by which two par-ticles merge to form a larger one. The distribution of particle sizes over time may bedescribed by the so-called Smoluchowski’s coagulation equation. This integrodifferentialequation exhibits complex non-local behaviour that strongly depends on the coagulationrate considered. We first discuss well-posedness results for the Smoluchowski’s equationfor a large class of coagulation kernels as well as the existence and nonexistence of sta-tionary solutions in the presence of a source of small particles. The existence result usesSchauder fixed point theorem, and the nonexistence result relies on a flux formulationof the problem and on power law estimates for the decay of stationary solutions with aconstant flux. We then consider a more general setting. We consider that particles maybe constituted by different chemicals, which leads to multi-component equations describ-ing the distribution of particle compositions. We obtain explicit solutions in the simplestcase where the coagulation kernel is constant by using a generating function. Using anapproximation of the solution we observe that the mass localizes along a straight line inthe size space for large times and large sizes.Peer reviewe

Coagulation equations for aerosol dynamics

Binary coagulation is an important process in aerosol dynamics by which two par-ticles merge to form a larger one. The distribution of particle sizes over time may bedescribed by the so-called Smoluchowski’s coagulation equation. This integrodifferentialequation exhibits complex non-local behaviour that strongly depends on the coagulationrate considered. We first discuss well-posedness results for the Smoluchowski’s equationfor a large class of coagulation kernels as well as the existence and nonexistence of sta-tionary solutions in the presence of a source of small particles. The existence result usesSchauder fixed point theorem, and the nonexistence result relies on a flux formulationof the problem and on power law estimates for the decay of stationary solutions with aconstant flux. We then consider a more general setting. We consider that particles maybe constituted by different chemicals, which leads to multi-component equations describ-ing the distribution of particle compositions. We obtain explicit solutions in the simplestcase where the coagulation kernel is constant by using a generating function. Using anapproximation of the solution we observe that the mass localizes along a straight line inthe size space for large times and large sizes.Peer reviewe

Microglia Response During Parkinson’s Disease: Alpha-Synuclein Intervention

The discovery of the central role played by the protein alpha-synuclein in Parkinson’s disease and other Lewy body brain disorders has had a great relevance in the understanding of the degenerative process occurring in these diseases. In addition, during the last two decades, the evidence suggesting an immune response in Parkinson’s disease patients have multiplied. The role of the immune system in the disease is supported by data from genetic studies and patients, as well as from laboratory animal models and cell cultures. In the immune response, the microglia, the immune cell of the brain, will have a determinant role. Interestingly, alpha-synuclein is suggested to have a central function not only in the neuronal events occurring in Parkinson’s disease, but also in the immune response during the disease. Numerous studies have shown that alpha-synuclein can act directly on immune cells, such as microglia in brain, initiating a sterile response that will have consequences for the neuronal health and that could also translate in a peripheral immune response. In parallel, microglia should also act clearing alpha-synuclein thus avoiding an overabundance of the protein, which is crucial to the disease progression. Therefore, the microglia response in each moment will have significant consequences for the neuronal fate. Here we will review the literature addressing the microglia response in Parkinson’s disease with an especial focus on the protein alpha-synuclein. We will also reflect upon the limitations of the studies carried so far and in the therapeutic possibilities opened based on these recent findings

Effectiveness of Surgery for Lumbar Spinal Stenosis : A Systematic Review and Meta-Analysis

Peer reviewedPublisher PD

Interacciones entre mamíferos marinos y la pesca de cerco en aguas Portuguesas

Marine mammal interactions with Portuguese purse-seine fisheries operating in four different ports (Figueira da Foz, Sesimbra, Setúbal, Sines) were studied (July-October 2003). Observers accompanied commercial fishing vessels and monitored 48 fishing trips. An interview survey of skippers was also carried out (n = 36). Three species of marine mammals were observed in 31 sightings during the commercials trips but only the species Delphinus delphis and the category Delphinidae were observed to interact with fishing activities. Small cetaceans were observed to sink, gather or disperse school fishes and damage gear. Mean CPUE and fishing effort values did not change significantly in the presence of dolphins (H = 0.06 and H = 0, both p>0.05). Results from Figueira da Foz indicate that cetaceans are attracted to fishing grounds with a high abundance of their prey-species. Fishermen reported three by-catch events off Figueira da Foz. Compared with other fisheries, purse-seine fishing does not seem to be among the most damaging to marine mammals.En este trabajo ha sido estudiada la interacción de los mamíferos marinos con la flota de cerco Portuguesa de julio a octubre de 2003, en cuatro puertos pesqueros (Figueira da Foz, Sesimbra, Setúbal, Sines). Los observadores acompañaron los barcos de pesca de cerco y supervisaron 48 viajes de pesca. Una encuesta por entrevista a los capitanes fue también realizada (n = 36). Tres especies de mamíferos marinos han sido observadas en 31 avistamentos durante los viajes de pesca, aunque sólamente la especie Delphinus delphis y la familia Delphinidae han interaccionado con las actividades de pesca. Los pequeños cetáceos fueron observados hundiendo, juntando o dispersando los cardumes de peces y a veces dañando las redes. Los valores del esfuerzo de pesca y de CPUE no cambiaron perceptiblemente con la presencia de delfines (H = 0.06 and H = 0, both p>0.05). Los resultados de Figueira da Foz indican que los cetáceos son atraídos a zonas de pesca con una elevada abundancia de sus especies presas. Los pescadores registraron tres acontecimientos de by-catch en Figueira da Foz. Cuando se compara con otras industrias pesqueras, la pesca de cerco no parece estar entre las que más dañan a los mamíferos marinos

Non-power law constant flux solutions for the Smoluchowski coagulation equation

It is well known that for a large class of coagulation kernels, Smoluchowski coagulation equations have particular power law solutions which yield a constant flux of mass along all scales of the system. In this paper, we prove that for some choices of the coagulation kernels there are solutions with a constant flux of mass along all scales which are not power laws. The result is proved by means of a bifurcation argument.Comment: 35 page

WHO ARE THE STUDENTS OF THE DENTISTRY PROGRAM AT ULBRA IN CANOAS, RS, WHAT THEY THINK AND WHAT THEY EXPECT OF THE JOB MARKET: A CROSS-SECTIONAL STUDY

Dentistry programs should prepare professionals with a generalist profile, having biological, scientific, technical, social and humanistic training. They should be trained for the reality of the job market and to practice Dentistry in both public and private settings, in order to provide leadership in the community in which they are placed. Objective: This study aims to analyze the socio-demographic profile, satisfaction with the program, self-evaluation of academic performance and expectations of the job market of students entering and exiting the Dentistry program of ULBRA/Canoas. Methodology: This is an observational, cross-sectional study conducted using a questionnaire with different questions for students entering and exiting the program in 2015. A questionnaire was developed with both open and closed objective, multiple-choice questions. It was given to 71 (86.5%) students enrolled in the program. Results: Most of the subjects are female, single, childless and between the ages of 17 and 36 years. Most chose Dentistry as a profession because they always liked or were interested in the health field. It was observed that the exiting students worked more in the areas of General Dentistry (90.4%) and Periodontics (77.0%) during their academic time, and intended to work in private practice (49.0%) and in the Unified Health System (65.0%). Conclusion: It was concluded that the profile of the entering and the exiting students is diverse, also that the students perceive that the greatest difficulty in the practice of Dentistry is the insertion and saturation of the job market

Dehydration process influences the phenolic profile, antioxidant and antimicrobial properties of Galium aparine L.

Galium aparine L. is a very disseminated plant in temperate zones, commonly known as clivers or bedstraw, belonging to the Rubiaceae family and it is traditionally used for its medicinal applications. In this study, G. aparine hydromethanolic extracts and infusions were prepared from air-dried and freeze-dried samples in order to assess their phenolic profile, antioxidant, antimicrobial, and cytotoxic properties. All the studied extracts revealed a similar phenolic profile, but the hydromethanolic extract obtained from the freeze-dried sample presented the highest concentration of phenolic compounds, followed by the respective infusion and the airdried sample hydromethanolic extract. The major compound detected in the extracts was 5-O-caffeoylquinic acid (from 145 to 163 mg/g extract). Regarding the bioactivity, in general, the extracts presenting higher phenolic concentrations also revealed enhanced bioactive properties. The EC50 values obtained in the antioxidant activity assays ranged from 13.5 to 884 μg/mL, with the freeze-dried sample hydromethanolic extract presenting the highest activity (13.5–555 μg/mL). Similar conclusions could be made in terms of antimicrobial properties, with this extract showing the lowest MIC (1.85–15 mg/mL), MBC (3.75–7.5 mg/mL), and MFC (3.75–20 mg/mL) values. None of the extracts revealed cytotoxicity. The results obtained in this study suggested that G. aparine extracts can be a good source of phenolic compounds with antioxidant and antimicrobial properties.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013); to FCT for L. Barros research contract; to FCT for the grant attributed to C. Pereira (SFRH/BPD/122650/2016) through the Programa Operacional Capital Humano (POCH) supported by the European Social Fund and National Funds of MCTES (Ministério da Ciência, Tecnologia, e Ensino Superior); and to FEDER-Interreg España-Portugal programme for financial support through the project 0377_Iberphenol_6_E. The authors are also grateful to the Serbian Ministry of Education, Science and Technological Development, grant number 173032 for financial support.info:eu-repo/semantics/publishedVersio