Experimental Study of a Single Droplet Impinging Upon a Heated Dry Surface Using Jet Fuel and Biofuel Mixtures

The aeronautical sector is dependent on fossil fuels which contribute to a considerable amount of pollutant emissions to the atmosphere. In an attempt to reduce these pollutant emissions in a short period of time and without several changes to the aircraft and their engines, this study focuses on the physical phenomena that happen inside the combustion chamber of an internal combustion engine during fuel injection. However, instead of considering only a conventional jet fuel, an alternative fuel is also investigated. The mixture is composed of at least 50% in volume of conventional jet fuel, as demanded by the current legislation, and a biofuel to decrease the consumption of petroleum-based fuels and to reduce pollutant emissions. The main goal of this study is to experimentally observe droplet impact on a heated dry stainless-steel surface for different fuel mixtures, impact energies (Weber number between 174 and 955, and Reynolds number between 1099 and 12365), and wall temperatures (Tw = 20 − 300 ºC) to identify the different heat regimes and the physical differences between the distinct sets of impact conditions. To achieve that purpose an experimental setup was designed and built including the acquisition of high-speed images, a droplet dispensing system, a heating device to accurately control the temperature of the target surface and the illumination of the impact site. To enhance the knowledge about the impacts, three different perspectives of the phenomena were captured. The typical front perspective, a second perspective where the camera has a ≈ 20◦ angle to the impact surface to capture more details of the impact, and finally, at a lower frame rate, an isometric perspective to measure the evaporation time. From these data, the impact regimes were identified and the influence of surface temperature, fluid properties, and impact energy was analyzed.Fundação para a Ciência e a Tecnologiainfo:eu-repo/semantics/publishedVersio

Optimization of in vitro model for growth of Gardnerella vaginalis biofilm

Bacterial vaginosis (BV) is the most common vaginal disorder in women of reproductive age. Despite its high prevalence, BV aetiology remains elusive. Recently, it was described that BV occurrence involves the presence of an adherent biofilm on vaginal epithelium, being Gardnerella vaginalis the predominant bacterial species. Furthermore, this bacterial biofilm persists on the vaginal epithelium after therapy with metronidazole, suggesting that G. vaginalis biofilm plays a key role in treatment failure and recurrence of BV. Despite the relevance of G. vaginalis biofilms in the BV pathogenesis, there has not been detailed information addressing the environmental conditions influence in G. vaginalis biofilm formation. In this sense, we designed a series of in vitro assays in order to evaluate the influence of some common culture conditions on biofilm formation of this bacterial species. Thus, we used four G. vaginalis strains isolated from women with BV and compared their biofilm-forming ability using distinct culture conditions, namely inoculum concentration, incubation period, feeding conditions and culture medium composition. Our results showed that growth conditions strongly influenced G. vaginalis biofilm formation and that biofilm formation was enhanced when starting the culture with a higher inoculum, supplemented the medium with glucose and using a fed-batch system. To conclude, this study provides new insights about optimized culture conditions for G. vaginalis biofilm formation, which is extremely important for future fundamental studies involving this bacterial community. This work was co-funded by FCT project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462), FCT Strategic Project PEst-C/SAU/UI0709/2011 and by QREN, FEDER, ON2 project (NORTE-07-0124-FEDER-000027)

Polyphenol metabolite pyrogallol-o-sulfate decreases microglial activation and vegf in retinal pigment epithelium cells and diabetic mouse retina

Funding Information: The authors acknowledge Fundacao para a Ciencia e Tecnologia for funding (PD/BD/114251/2016 scholarship to D.F. Santos; EXPL-BIM-MEC-1433-2013; PTDC/BTM/ORG/28121/2017 grants to G.A.Silva) and iNOVA4Health ? UIDB/Multi/04462/2020, a program financially supported by Funda??o para a Ci?ncia e Tecnologia/Ministerio da Educacao e Ciencia through national funds and co-funded by FEDER under the PT2020 Partnership Agreement, is also acknowledged. C.N.S. also acknowledges the European Research Council (ERC) under the European Union?s Horizon 2020 Research and Innovation Programme under Grant Agreement No. 804229. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.(Poly)phenol-derived metabolites are small molecules resulting from (poly)phenol metab-olization after ingestion that can be found in circulation. In the last decade, studies on the impact of (poly)phenol properties in health and cellular metabolism accumulated evidence that (poly)phenols are beneficial against human diseases. Diabetic retinopathy (DR) is characterized by inflammation and neovascularization and targeting these is of therapeutic interest. We aimed to study the effect of pyrogallol-O-sulfate (Pyr-s) metabolite in the expression of proteins involved in retinal glial acti-vation, neovascularization, and glucose transport. The expression of PEDF, VEGF, and GLUT-1 were analyzed upon pyrogallol-O-sulfate treatment in RPE cells under high glucose and hypoxia. To test its effect on a diabetic mouse model, Ins2Akita mice were subjected to a single intraocular injection of the metabolite and the expression of PEDF, VEGF, GLUT-1, Iba1, or GFAP measured in the neural retina and/or retinal pigment epithelium (RPE), two weeks after treatment. We observed a significant decrease in the expression of pro-angiogenic VEGF in RPE cells. Moreover, pyrogallol-O-sulfate significantly decreased the expression of microglial marker Iba1 in the diabetic retina at different stages of disease progression. These results highlight the potential pyrogallol-O-sulfate metabolite as a preventive approach towards DR progression, targeting molecules involved in both inflammation and neovascularization.publishersversionpublishe

Dibucaine in Ionic-Gradient Liposomes: Biophysical, Toxicological, and Activity Characterization

Administration of local anesthetics is one of the most effective pain control techniques for postoperative analgesia. However, anesthetic agents easily diffuse into the injection site, limiting the time of anesthesia. One approach to prolong analgesia is to entrap local anesthetic agents in nanostructured carriers (e.g., liposomes). Here, we report that using an ammonium sulphate gradient was the best strategy to improve the encapsulation (62.6%) of dibucaine (DBC) into liposomes. Light scattering and nanotracking analyses were used to characterize vesicle properties, such as, size, polydispersity, zeta potentials, and number. In vitro kinetic experiments revealed the sustained release of DBC (50% in 7 h) from the liposomes. In addition, in vitro (3T3 cells in culture) and in vivo (zebrafish) toxicity assays revealed that ionic-gradient liposomes were able to reduce DBC cyto/cardiotoxicity and morphological changes in zebrafish larvae. Moreover, the anesthesia time attained after infiltrative administration in mice was longer with encapsulated DBC (27 h) than that with free DBC (11 h), at 320 μM (0.012%), confirming it as a promising long-acting liposome formulation for parenteral drug administration of dibucaine.Fil: Couto, Verônica M.. Universidade Estadual de Campinas; BrasilFil: Prieto, Maria Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Grupo Vinculado al IMBICE - Grupo de Biología Estructural y Biotecnología-Universidad Nacional de Quilmes - GBEyB | Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Grupo Vinculado al IMBICE - Grupo de Biología Estructural y Biotecnología-Universidad Nacional de Quilmes - GBEyB | Universidad Nacional de la Plata. Instituto Multidisciplinario de Biología Celular. Grupo Vinculado al IMBICE - Grupo de Biología Estructural y Biotecnología-Universidad Nacional de Quilmes - GBEyB; ArgentinaFil: Igartúa, Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Grupo Vinculado al IMBICE - Grupo de Biología Estructural y Biotecnología-Universidad Nacional de Quilmes - GBEyB | Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Grupo Vinculado al IMBICE - Grupo de Biología Estructural y Biotecnología-Universidad Nacional de Quilmes - GBEyB | Universidad Nacional de la Plata. Instituto Multidisciplinario de Biología Celular. Grupo Vinculado al IMBICE - Grupo de Biología Estructural y Biotecnología-Universidad Nacional de Quilmes - GBEyB; ArgentinaFil: Feas, Daniela Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Grupo Vinculado al IMBICE - Grupo de Biología Estructural y Biotecnología-Universidad Nacional de Quilmes - GBEyB | Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Grupo Vinculado al IMBICE - Grupo de Biología Estructural y Biotecnología-Universidad Nacional de Quilmes - GBEyB | Universidad Nacional de la Plata. Instituto Multidisciplinario de Biología Celular. Grupo Vinculado al IMBICE - Grupo de Biología Estructural y Biotecnología-Universidad Nacional de Quilmes - GBEyB; ArgentinaFil: Ribeiro, Lígia N.M.. Universidade Estadual de Campinas; BrasilFil: Silva, Camila M.G.. Universidade Estadual de Campinas; BrasilFil: Castro, Simone R.. Universidade Estadual de Campinas; BrasilFil: Guilherme, Viviane A.. Universidade Estadual de Campinas; BrasilFil: Dantzger, Darlene D.. Universidade Estadual de Campinas; BrasilFil: Machado, Daisy. Universidade Estadual de Campinas; BrasilFil: Alonso, Silvia del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Grupo Vinculado al IMBICE - Grupo de Biología Estructural y Biotecnología-Universidad Nacional de Quilmes - GBEyB | Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Grupo Vinculado al IMBICE - Grupo de Biología Estructural y Biotecnología-Universidad Nacional de Quilmes - GBEyB | Universidad Nacional de la Plata. Instituto Multidisciplinario de Biología Celular. Grupo Vinculado al IMBICE - Grupo de Biología Estructural y Biotecnología-Universidad Nacional de Quilmes - GBEyB; ArgentinaFil: de Paula, Eneida. Universidade Estadual de Campinas; Brasi

Modificação de betumes com aditivos líquidos para aplicação em países tropicais

A modificação de betumes é uma das soluções mais utilizadas na pavimentação, sobretudo em países com climas quentes, pois permite minimizar problemas tais como o fendilhamento, o envelhecimento do betume, e em especial as deformações permanentes. Este trabalho visa estudar uma solução para modificação do betume de modo a contornar os problemas acima indicados do betume puro existente nesses países. Para isso foram utilizados dois aditivos líquidos, SBR líquido e ácido polifosfórico (PPA), e foram estudadas diferentes percentagens de adição dos mesmos em betumes puros, de modo a selecionar o aditivo com mais potencial e a percentagem em que devia ser incorporado.Fundos QREN, através da ANI, no âmbito do projeto Tropical-Pav – “Soluções de Pavimentação Rodoviária para Climas Tropicais”, num consórcio constituído por duas empresas e quatro entidades do Sistema Científico e Tecnológico Nacional (SCTN), nomeadamente Elevo Grupo, Mota-Engil Engenharia e Construção, Instituto Superior Técnico, Laboratório Nacional de Engenharia Civil, Universidade de Coimbra e Universidade do Minho

Insights on bubble encapsulation after drop impact on thin liquid films

The accurate understanding of the phenomenology of drop impact onto dry/ wetted and cold/heated surfaces is increasingly relevant to implement biofuels in civil aviation. The outcome of drop impact depends on the pre-impact conditions and a seldom researched event is the encapsulation of a bubble when this impact occurs on thin liquid films. Therefore, the goal of the experimental work reported is to investigate the mechanism of this bubble encapsulation. Results show that the mechanism leading to a bubble formation has two stages. In the first stage, after the drop impacts a steady liquid film, a prompt splash occurs followed by a crown splash. The uprising sheet propagates in an almost normal direction relative to the liquid film, but its radius at the base continues to expand, eventually leading to the inward collapse of the crown-bounding rim encapsulating air inside the dome. In the second stage, three different phenomenologies of bubble encapsulation can occur. At the top of the closed crown, one jet (phenomenology 1) or two jets are formed (phenomenologies 2 and 3). For phenomenology 2, the upward jet eventually collapses due to gravitational influence, while the downward jet continues to grow until it reaches the liquid film, attaching to it, stretching and detaching from the top at the hemispheric thin sheet, forming a bubble. In phenomenology 3, the upward jet is high enough to allow its breakup and ejection of one large droplet before the collapse of the upward jet. Many secondary droplets fall on the bubble and one of them will eventually break the dome, leading to more secondary atomization. Additionally, the first perturbation imposed on the liquid film by the droplet impact is studied and an empirical correlation is proposed for its propagation velocity. Finally, bubble geometry is investigated.Fundação para a Ciência e a Tecnologiainfo:eu-repo/semantics/publishedVersio

Analysis And Visualization Of The Perturbations Imposed On The Liquid Film By Crown Sheet Collapse Or Closure

Bubble encapsulation is a phenomenon that results from droplet impact on a liquid film for very specific impact conditions. After splashing, the crown liquid sheet starts to bend inwards, and eventually, the jets at the top of the crown merge and form a perfect empty bubble. This bubble bursts due to the impingement of a secondary droplet that falls in the spherical dome or by reaching its critical thickness. However, bubble encapsulation is seldom reported in the literature. Due to that, this work focuses on understanding better its dynamics and formation mechanisms. By using a bottom perspective of the phenomenon, important information about its dynamics is disclosed. From the bottom shadowgraphs, the capillary waves and the perturbations imposed on the steady liquid film are clearly observed. From previous works, it was confirmed that its occurrence is systematic, so, one of the goals of this study is to realize how the impact conditions influence the phenomenon and if we can establish a criterion for its occurrence. Despite the scarce information about the phenomenon, there are some works about it that are focused on the cavity underneath the bubble. In this study, we observed the cavity and conclude that the cavity shape does not influence the bubble encapsulation phenomenon. Finally, the crown closure time was measured for a specific set of impact conditions and it was analyzed depending on the dimensionless thickness of the liquid film.Fundação para a Ciência e a Tecnologiainfo:eu-repo/semantics/publishedVersio

Insights on Bubbling Formation after Drop Impact on Thin Liquid Films

Over the years, the phenomena obtained when a drop impinges upon a dry, wetted or heated surface have been thoroughly studied. In previous works, the existence of splash was investigated by the authors with the goal of evaluating the possible implementation of biofuels in the civil aviation and it was found an episode of a phenomenon, seldom reported in the literature under specific pre-impingement conditions. The mechanism that leads to a bubble formation has two stages. After the drop impacts a steady liquid film, prompt splash occurs followed by crown splash. In the first stages of crown splash, the uprising sheet propagates almost normal to the liquid film, but its radius at the base continues to expand, eventually leading to the inward collapse of the crown bounding rim. Thus, the top of the crown closes in a bubble-like shape with the formation of two jets, one upwards and other downwards. The upward jet eventually disappears due to gravitational influence, while the downward jet continues to grow until it reaches the liquid film, attaching to it, stretching and detaching from the top at the hemispheric thin-sheet, forming a perfect bubble. Many secondary droplets fall on the bubble and one of them will eventually break the dome, leading to more secondary atomization. The few works reported in the literature referring to this phenomenon as “bubbling” or “floating bubble,” scarcely explore the hydrodynamic mechanism associated with this bubble formation and occurrence, mainly focusing on droplets impacting upon deep pools. However, in a previous study, the authors observed this event for a liquid film dimensionless thickness of 0:5 in a fluid mixture of Jet A-1 and biofuel NEXBTL. In this study, the impact conditions in the experiments performed allow to recreate the floating bubble with 100% of occurrence. After that, the authors present an extensive characterization of the bubbling phenomenon to understand better the mechanisms which lead to its formation, as well as its practical significance. A high-speed digital camera acquires several images of the floating bubble formation from different points of view (side and bottom). Namely, capturing the phenomenon from below, high-quality images allow retrieving essential data to describe the hydrodynamic mechanism accurately. The most relevant features include the bubble height and diameter, and the propagation velocity of the first perturbation imposed on the liquid film.info:eu-repo/semantics/publishedVersio

Metales pesados en suelos de la planicie costera del Río de la Plata, partidos de Ensenada y Berisso

Los datos de metales pesados determinados en diferentes horizontes de suelo de la Planicie Costera del Gran La Plata, no muestran, en términos generales, gran dispersión ni concentraciones mayores a los valores de referencia regionales aportados por otros autores. Las concentraciones máximas consideradas ecotóxicas en suelos de la región Pampeana brindan valores de 50 mg kg-1 para cobre, 100 mg kg-1 para plomo y 150 mg kg-1 para cinc. Si consideramos los promedios para la totalidad de los horizontes superficiales y subsuperficiales estudiados, se verifican valores de Cu: 45,73 mg kg-1, Zn: 105, 8 mg kg-1 y Pb. 34,38 mg kg-1, con valores decrecientes de desviación standard de Zn-Pb-Cu de 130,81- 51,12- 24,75. Las escasas excepciones se encuentran en sectores cercanos a áreas urbanas y de intensa actividad industrial como por ejemplo en la zona de influencia del Arroyo Doña Flora de la localidad de Ensenada con valores notablemente superiores de Cu: 155 mg kg-1, Zn: 283 mg kg-1 y Pb. 134 mg kg-1. Los suelos de la Planicie Costera presentan dos clases texturales, suelos arenosos en la Llanura Aluvional, cercanos a la línea de costa y suelos ricos en arcillas esmectíticas en la Llanura de Fango. En ambas unidades, los perfiles de suelos, no presentan variaciones verticales importantes de estos elementos. En el primer caso, este hecho se explica por la homogeneidad arenosa de sus materiales y su relativa juventud, siendo la retención de metales baja. En el segundo caso, se atribuye a los materiales arcillosos homogéneos en todo el perfil de suelo que conjuntamente con la materia orgánica generan una alta retención de metales.Fil: Manassero, Marcelo Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina; Consejo Nacional de Invest.cientif.y Tecnicas. Centro Cientifico Tecnol.conicet - la Plata. Centro de Invest.geologicas (i); Argentina;Fil: Da Silva, Mario Marcelo. Universidad Nacional de la Plata. Facultad de Cs.naturales y Museo. Instituto de Geomorfologia y Suelos; Argentina;Fil: Boff, Laura Daniela. Universidad Nacional de la Plata. Facultad de Cs.naturales y Museo. Instituto de Geomorfologia y Suelos; Argentina;Fil: Hurtado, Martín A.

Application of Infrared Thermal Imaging in a Violinist with Temporomandibular Disorder

Temporomandibular disorders (TMD) consist of a group of pathologies that affect the masticatory muscles, temporomandibular joints (TMJ), and/or related structures. String instrumentalists, like many orchestra musicians, can spend hours with head postures that may influence the biomechanical behavior of the TMJ and the muscles of the craniocervicomandibular complex (CCMC). The adoption of abnormal postures acquired during performance by musicians can lead to muscular hyperactivity of the head and cervical muscles, with the possible appearance of TMD. Medical infrared thermography is a non-invasive procedure that can monitor the changes in the superficial tissue related to blood circulation and may serve as a complement to the clinical examination. The objective of this study was to use infrared thermography to evaluate, in one subject, the cutaneous thermal changes adjacent to the CCMC that occur before, during, and after playing a string instrument