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1.
Polymers (Basel) ; 16(2)2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38256994

RESUMO

Polymer-based (nano)composite foams containing conductive (nano)fillers limit electromagnetic interference (EMI) pollution, and have been shown to act as good shielding materials in electronic devices. However, due to their high (micro)structural complexity, there is still a great deal to learn about the shielding mechanisms in these materials; understanding this is necessary to study the relationship between the properties of the microstructure and the porous structure, especially their EMI shielding efficiency (EMI SE). Targeting and controlling the electrical conductivity through a controlled distribution of conductive nanofillers are two of the main objectives when combining foaming with the addition of nanofillers; to achieve this, both single or combined nanofillers (nanohybrids) are used (as there is a direct relationship between electrical conductivity and EMI SE), as are the main shielding mechanisms working on the foams (which are expected to be absorption-dominated). The present review considers the most significant developments over the last three years concerning polymer-based foams containing conductive nanofillers, especially carbon-based nanofillers, as well as other porous structures created using new technologies such as 3D printing for EMI shielding applications. It starts by detailing the microcellular foaming strategy, which develops polymer foams with enhanced EMI shielding, and it particularly focuses on technologies using supercritical CO2 (sCO2). It also notes the use of polymer foams as templates to prepare carbon foams with high EMI shielding performances for high temperature applications, as well as a recent strategy which combines different functional (nano)fillers to create nanohybrids. This review also explains the control and selective distribution of the nanofillers, which favor an effective conductive network formation, which thus promotes the enhancement of the EMI SE. The recent use of computational approaches to tailor the EMI shielding properties are given, as are new possibilities for creating components with varied porous structures using the abovementioned materials and 3D printing. Finally, future perspectives are discussed.

2.
Nanomaterials (Basel) ; 13(20)2023 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-37887899

RESUMO

This Topic on the "Application of Graphene-Based Materials", which consists of a total of twenty-six articles, including two review articles, written by research groups of experts in the field, considers the most recent research and trends on the synthesis and characterization of graphene-based materials, including nanohybrids, intended for a vast array of high-demanding technological applications, namely batteries/fuel cells, aerogels, laser technology, sensors, electronic/magnetic devices, catalysts, etc [...].

3.
Movimento (Porto Alegre) ; 29: e29012, 2023.
Artigo em Português | LILACS | ID: biblio-1506756

RESUMO

Resumo A Luta Marajoara (LM) vem aos poucos sendo conhecida nacional e internacionalmente como uma prática de combate corporal de expressiva efetividade e com elementos culturais importantes. O presente texto resulta de investigação exploratória que objetivou compreender, a partir das percepções de atletas e ex-atletas da LM, as tensões que envolvem essa prática corporal no âmbito de suas dimensões cultural, educacional e esportiva. A amostra é composta por 13 participantes masculinos, com idade entre 30 a 60 anos, residentes no Arquipélago do Marajó. Para a coleta de dados, foi utilizado um roteiro de entrevista semiestruturado com sete perguntas abertas. Os resultados demonstraram que a LM atravessa um processo de esportivização, de escolarização e de busca pela preservação de suas tradições. Percebe-se, ainda, a crença de que o ensino das tradições da LM para crianças pode resgatar o interesse pela modalidade, destacando o aspecto da identidade cultural do povo marajoara. (AU)


Abstract Marajoara Wrestling (MW) is being recognized, nationally and internationally, as a practice of corporal combat of expressive effectivity and with important cultural elements. The following text is the product of exploratory investigation that had the objective of identifying the perspective of athletes and former athletes of the modality about MW. The sample is composed of 13 male participants, from 30 to 60 years old, residents of the Marajó Archipelago. For the data collection a semi-structured interview script with seven open questions was utilized. The results show that MW is undergoing a process of sportification, schooling and of longing for the preservation of its traditions. It is perceptible, furthermore, that the schooling of traditions of MW to children can retrieve the interest for the modality, giving emphasis to the cultural identity of the marajoara people. (AU)


Resumen La Lucha Marajoara (LM) viene siendo, poco a poco, conocida nacional e internacionalmente, como una práctica de combate corporal de expresiva efectividad y con elementos culturales importantes. El siguiente texto resulta de la investigación exploratoria que tuvo como objetivo la identificación de perspectivas de atletas y ex atletas de LM. La muestra está compuesta por 13 participantes masculinos, con edad entre 30 y 60 años, residentes del Archipiélago de Marajó. Para la recolección de datos fue utilizado un plan de preguntas semiestructuradas con siete cuestiones abiertas. Los resultados demuestran que la LM pasa por un proceso de deportificación, de escolarización y de búsqueda por la preservación de sus tradiciones. Es nítido, además, que la enseñanza de las tradiciones de la LM a niños puede rescatar el interés de ellas por la modalidad, destacando el aspecto de la identidad cultural del pueblo marajoara. (AU)


Assuntos
Humanos , Masculino , Esportes , Cultura
4.
J Endod ; 47(7): 1157-1165, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33901544

RESUMO

INTRODUCTION: The present study aimed to describe an in vitro study model to investigate root surface strain (RSS) and its correlation with the initiation/propagation of microcracks during different endodontic procedures. METHODS: Four lower human incisors extracted microcrack free were selected by micro-computed tomographic imaging. Two strain gauges were bonded to the root surface of each incisor. Then, the teeth were prepared to reproduce the periodontal ligament artificially. The gauges were attached to a data acquisition system. The RSS was recorded during the entire endodontic procedure, which consisted of accessing the endodontic cavity, cleaning, shaping preparation with an Mtwo rotary system (VDW, Munich, Germany), and filling with a standardized technique. Each incisor was submitted to a different retreatment protocol and supplementary cleaning method as follows: (1) Reciproc (RC, VDW) + Flatsonic (FS; Helse, Santa Rosa de Viterbo, Brazil), (2) RC + XP-endo Finisher (XPF; FKG Dentaire, La Chaux-de-Fonds, Switzerland), (3) Mtwo retreatment (MR) + FS, and (4) MR + XPF. Finally, the teeth were rescanned to establish the postoperative microcrack formation by 2 well-trained and blinded examiners. RESULTS: The maximum and minimum RSS values were -120 and 510 microstrains, respectively, for all of the files. RC showed the highest RSS values during endodontic retreatment compared with MR. FS demonstrated a higher variation between the minimum and maximum RSS than XPF. No microcracks were observed in the specimens. CONCLUSIONS: This preliminary study proposed an experimental model that would combine 2 methods to evaluate the effects of endodontic systems on dentin. Although strain gauges would provide data on the stresses created, the pre- and postoperative evaluation of micro-computed tomographic images would enable microcrack formation to be determined.


Assuntos
Cavidade Pulpar , Preparo de Canal Radicular , Brasil , Humanos , Retratamento , Microtomografia por Raio-X
5.
Polymers (Basel) ; 13(3)2021 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-33573026

RESUMO

Polysulfone nanocomposite foams containing variable amounts of graphene nanoplatelets (0-10 wt%) were prepared by water vapor-induced phase separation (WVIPS) and supercritical CO2 (scCO2) dissolution. WVIPS foams with two ranges of relative densities were considered, namely, between 0.23 and 0.41 and between 0.34 and 0.46. Foams prepared by scCO2 dissolution (0.0-2.0 wt% GnP) were obtained with a relative density range between 0.35 and 0.45. Although the addition of GnP affected the cellular structure of all foams, they had a bigger influence in WVIPS foams. The storage modulus increased for all foams with increasing relative density and GnP's concentration, except for WVIPS PSU-GnP foams, as they developed open/interconnected cellular structures during foaming. Comparatively, foams prepared by scCO2 dissolution showed higher specific storage moduli than similar WVIPS foams (same relative density and GnP content), explained by the microcellular structure of scCO2 foams. As a result of the plasticizing effect of CO2, PSU foams prepared by scCO2 showed lower glass transition temperatures than WVIPS foams, with the two series of these foams displaying decreasing values with incrementing the amount of GnP.

6.
Polymers (Basel) ; 13(2)2021 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-33478149

RESUMO

This work is made to ascertain the effects of mineral fillers, namely calcium carbonate and talc, on the morphology and properties of multilayer polypropylene (PP)/high-density polyethylene (HDPE) porous membranes. Multilayer membranes were prepared using the three-stage Melt-Extrusion, Annealing and Uniaxial Stretching (MEAUS) process. The orientation of PP's crystalline phase was affected by both the flow-induced crystallization and the heterogeneous nucleation promoted by the fillers. A synergistic effect was observed in the filled samples due to the generation of pores after the stretching-induced lamellae separation and the debonding of mineral fillers from the polymeric matrix. The fillers increased the porous surface, leading to an increase of permeance to air, being this effect more marked at higher filler contents. Talc showed a higher efficiency to create porous surfaces when compared to calcium carbonate. The thermal stability of the membranes increased with filler addition, as well as their stiffness and strength.

7.
Conexões (Campinas, Online) ; 19: e021042, 2021.
Artigo em Português | LILACS | ID: biblio-1348570

RESUMO

Introdução: o progresso ocorrido nas últimas décadas em termos de práticas esportivas tem sido imenso, em especial em algumas modalidades esportivas de combate. Frente a este contexto é possível situar a Luta Marajoara (LM), modalidade ainda pouco conhecida no mundo acadêmico. Objetivo: descrever as principais discussões e encaminhamentos envolvendo a LM, oriundos dos debates do I Fórum Paraense de Luta Marajoara. Método: o relato tem um caráter exploratório e descritivo, configurando-se como um estudo qualitativo, pois busca identificar questões significativas do universo da modalidade para apontar futuros encaminhamentos. Resultados e discussão: a partir das observações e posicionamentos relevantes do Fórum constatou-se que os elementos que suscitaram os maiores encaminhamentos e direcionamentos estão relacionados com ações que envolvem a dimensão esportiva da LM. Conclusão: ações relacionadas a organização esportiva são as mais priorizadas, tal constatação sinaliza para a esportivização da LM, algo legítimo considerando que a modalidade é genuinamente brasileira e de grande importância para cultura nacional.


Introduction: the progress made in the last decades in terms of sports practices has been immense, especially in some combat sports. Faced with this context, it is possible to situate Marajoara Wrestling (MW), a modality still little known in the academic world. Objective: to describe the main discussions and referrals involving the MW, arising from the debates of the 1st Para Forum of Marajoara Fight. Method: the report has an exploratory and descriptive character, configuring itself as a qualitative study, as it seeks to identify significant issues in the universe of the modality to point out future referrals. Results and discussion: Based on the relevant observations and positions of the Forum, it was found that the elements that gave rise to the greatest referrals and orientations are related to actions that involve the sports dimension of MW. Conclusion: actions related to sports organization are the most prioritized, this finding signals the sporting of MW, something legitimate considering that the sport is genuinely Brazilian and of great importance for national culture.


Introducción: el progreso realizado en las últimas décadas en términos de prácticas deportivas ha sido inmenso, especialmente en algunos deportes de combate. Frente a este contexto, es posible situar a Luta Marajoara (LM), una modalidad aún poco conocida en el mundo académico. Objetivo: describir las principales discusiones y referencias relacionadas con el LM, que surgen de los debates del 1er Foro de Lucha de Marajoara. Método: el informe tiene un carácter exploratorio y descriptivo, configurándose como un estudio cualitativo, ya que busca identificar problemas significativos en el universo de la modalidad para señalar futuras referencias. Resultados y discusión: Basado en las observaciones y posiciones relevantes del Foro, se encontró que los elementos que dieron lugar a las mayores referencias y orientaciones están relacionados con acciones que involucran la dimensión deportiva de LM. Conclusión: las acciones relacionadas con la organización deportiva son las más prioritarias, este hallazgo señala el deporte de LM, algo legítimo teniendo en cuenta que el deporte es genuinamente brasileño y de gran importancia para la cultura nacional.


Assuntos
Humanos , Educação Física e Treinamento , Esportes , Cultura , Pesquisa Qualitativa
8.
Nanomaterials (Basel) ; 10(12)2020 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-33291598

RESUMO

Graphene nanoplatelet (GnP)-filled polysulfone (PSU) cellular nanocomposites, prepared by two different methods-namely, water vapor-induced phase separation (WVIPS) and supercritical CO2 dissolution (scCO2) foaming-were produced with a range of densities from 0.4 to 0.6 g/cm3 and characterized in terms of their structure and electrical conduction behavior. The GnP content was varied from 0 to 10 wt%. The electrical conductivity values were increased with the amount of GnP for the three different studied foam series. The highest values were found for the microcellular nanocomposites prepared by the WVIPS method, reaching as high as 8.17 × 10-2 S/m for 10 wt% GnP. The variation trend of the electrical conductivity for each series was analyzed by applying both the percolation and the tunneling models. Comparatively, the tunneling model showed a better fitting in the prediction of the electrical conductivity. The preparation technique of the cellular nanocomposite affected the resultant cellular structure of the nanocomposite and, as a result, the porosity or gas volume fraction (Vg). A higher porosity resulted in a higher electrical conductivity, with the lightest foams being prepared by the WVIPS method, showing electrical conductivities two orders of magnitude higher than the equivalent foams prepared by the scCO2 dissolution technique.

9.
Facial Plast Surg Clin North Am ; 28(3): 303-310, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32503716

RESUMO

The various rhytidectomy techniques share a common goal of safe repositioning of the facial soft tissues with a lasting effect. This article reviews rhytidectomy approaches and the current methods and practice patterns of the senior author. It includes a discussion of the extended sub-superficial musculoaponeurotic system rhytidectomy technique, which, in the opinion of the senior author, offers the best result with respect to neck rhytids, cervicomental angle and jawline definition, and improvement of jowling. With its ability to be readily coupled with a deep plane dissection, when indicated, this technique becomes indispensable in the facial plastic surgeon's armamentarium.


Assuntos
Face/cirurgia , Ritidoplastia/métodos , Sistema Musculoaponeurótico Superficial/cirurgia , Retalhos Cirúrgicos , Dissecação/métodos , Humanos , Pescoço/cirurgia
10.
Polymers (Basel) ; 12(1)2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31877642

RESUMO

Polysulfone (PSU) foams containing 0-10 wt% graphene nanoplatelets (GnP) were prepared using two foaming methods. Alongside the analysis of the cellular structure, their thermal conductivity was measured and analyzed. The results showed that the presence of GnP can affect the cellular structure of the foams prepared by both water vapor induced phase separation (WVIPS) and supercritical CO2 (scCO2) dissolution; however, the impact is greater in the case of foams prepared by WVIPS. In terms of thermal conductivity, the analysis showed an increasing trend by incrementing the amount of GnP and increasing relative density, with the tortuosity of the cellular structure, dependent on the used foaming method, relative density, and amount of GnP, playing a key role in the final value of thermal conductivity. The combination of all these factors showed the possibility of preparing PSU-GnP foams with enhanced thermal conductivity at lower GnP amount by carefully controlling the cellular structure and relative density, opening up their use in lightweight heat dissipators.

11.
Polymers (Basel) ; 11(7)2019 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-31336996

RESUMO

Advances in nanotechnology have boosted the development of more efficient materials, with emerging sectors (electronics, energy, aerospace, among others) demanding novel materials to fulfill the complex technical requirements of their products [...].

12.
Polymers (Basel) ; 11(2)2019 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-30960311

RESUMO

Polyetherimide (PEI) foams with graphene nanoplatelets (GnP) were prepared by supercritical carbon dioxide (scCO2) dissolution. Foam precursors were prepared by melt-mixing PEI with variable amounts of ultrasonicated GnP (0.1⁻2.0 wt %) and foamed by one-step scCO2 foaming. While the addition of GnP did not significantly modify the cellular structure of the foams, melt-mixing and foaming induced a better dispersion of GnP throughout the foams. There were minor changes in the degradation behaviour of the foams with adding GnP. Although the residue resulting from burning increased with augmenting the amount of GnP, foams showed a slight acceleration in their primary stages of degradation with increasing GnP content. A clear increasing trend was observed for the normalized storage modulus of the foams with incrementing density. The electrical conductivity of the foams significantly improved by approximately six orders of magnitude with only adding 1.5 wt % of GnP, related to an improved dispersion of GnP through a combination of ultrasonication, melt-mixing and one-step foaming, leading to the formation of a more effective GnP conductive network. As a result of their final combined properties, PEI-GnP foams could find use in applications such as electrostatic discharge (ESD) or electromagnetic interference (EMI) shielding.

13.
Rev. bras. ciênc. vet ; 25(2): 55-59, abr./jun. - 2018. il.
Artigo em Português | LILACS | ID: biblio-987951

RESUMO

O objetivo deste estudo foi avaliar os efeitos do butafosfan isolado ou associado à cianocobalamina sobre marcadores do metabolismo energético, mineral e inflamatório, produção de leite e índice de funcionalidade hepática (IFH) de vacas leiteiras primíparas. Vinte e três vacas da raça Holandês foram aleatoriamente distribuídas em três grupos experimentais: Grupo Combinação (COM, n = 8), que recebeu 100 mL da combinação de butafosfan+cianocobalamina;Grupo Butafosfan (BUT, n = 8), que recebeu 100 mL de solução aquosa de Butafosfan; e Grupo Controle (CTL, n = 7), que recebeu 100 mL de solução fisiológica 0,9%. Todos os animais recebram 5 doses subcutâneas de 20 mL a cada 24 horas, iniciando logo após o parto. Amostras de sangue foram coletadas nos dias 0, 1, 2, 3, 4, 5, 10, 15, 20 e 28 para análises de cálcio, fósforo, ácidos graxos não esterificados (AGNEs) e ß-hidroxibutirato (BHBA). Albumina, bilirrubina, colesterol total, haptoglobina e paraoxonase foram analisadas nos dias 0, 3, 5, 10, 15, 20 e 28. Foi avaliado o escore de condição corporal e a produção leiteira até 60 dias pós-parto. Níveis reduzidos de BHBA (P<0,05) foram encontrados no grupo BUT. Animais com alto IFH apresentaram menores níveis de BHBA (P<0,05) e tendência de redução nos níveis de AGNEs (P<0,10), porém o IFH não foi influenciado pelos tratamentos. Apesar de o butafosfan reduzir os níveis de BHBA, o índice de funcionalidade hepática de vacas primímaras não foi influenciado pelos tratamentos.


The objective of study was to evaluate the effects of butafosfan and cyanocobalamin on markers of energetic, mineral and inflammatory metabolism, milk production and the liver functionality index (LFI) of primiparous dairy cows. Twenty-three Holstein cows were allocated into: Combination group (COM, n = 8), receiving 100 mL of Catosal®; Butafosfan group (BUT, n = 8) that received 100 mL of aqueous Butafosfan; and Control (CTL, n = 7), receiving 100 mL of 0.9% saline. All the animals received 100 mL (5 doses of 20mL every 24h), subcutaneously, beginning soon after calving. Blood samples were collected on days 0, 1, 2, 3, 4, 5, 10, 15, 20 and 28 for analysis of calcium, phosphorus, non-esterified fatty acids (NEFA) and ß-hydroxybutyrate (BHB). The analysis of albumin, bilirubin, cholesterol, haptoglobin and paraoxonase were performed on days 0, 3, 5, 10, 15, 20 and 28. We evaluated body condition score (BCS) and milk production (kg /day) until day 60 after calving. The LFI was determined considering the plasma levels of total cholesterol, albumin and bilirubin on days 3 and 28 after calving. The BUT group showed lower BHB levels (P<0.05) than CTL group. The animals from group with high LFI had lower concentrations of BHB (P<0.05) and a trend of lower concentrations of NEFA (P<0.10), whereas the animals with poor liver function (low) showed tendency to have lower level of albumin (P <0.10). Howerver, the LFI was not affected by treatments (P> 0.05). In conclusion, despite the butafosfan and cyanocobalamin modulate energy metabolism in this study the hepatic functionality index was not affected by treatments.


Assuntos
Animais , Bovinos , Glucose
14.
Aesthet Surg J ; 38(10): 1065-1073, 2018 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-29596568

RESUMO

BACKGROUND: A change in nasal tip rotation is a very common maneuver performed during rhinoplasty. Among the many techniques used to achieve this goal is the tongue-in-groove (TIG). OBJECTIVES: This study addresses the long-term effect of the TIG on the nasal tip rotation 1 year after rhinoplasty. METHODS: The authors prospectively identified patients who were submitted to a rhinoplasty with a TIG maneuver over a period of 1 year. The angle of rotation was measured along the nostril axis angle. The data were analyzed using the t test and a linear regression model. RESULTS: Seventeen patients were included. The average preoperative tip rotation was 93.95° (SD, 3.12°). Immediate postoperative tip rotation averaged 114.47° (SD, 3.79°). At the 1-year follow-up appointment, the tip rotation averaged 106.55° (SD, 3.54°). There was a significant loss of rotation at the 1-year postoperative visit (P < 0.0001), with an average loss of 7.9° (SD, 3.25°), which amounted to 6.8%. The preoperative rotation didn't affect the amount of loss of rotation (P = 0.04). It can be estimated that, for every degree of rotation that is changed at surgery, the tip can be expected to lose 0.35 degrees over the first year. CONCLUSIONS: TIG is a more dependable technique than the ones that rely on healing and contraction to obtain rotation. Our data demonstrated a significant loss of rotation during the first year. This suggests that the surgeon needs to slightly overcorrect the tip rotation to account for this loss.


Assuntos
Septo Nasal/cirurgia , Complicações Pós-Operatórias/prevenção & controle , Rinoplastia/métodos , Técnicas de Sutura , Adulto , Antropometria , Estética , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Septo Nasal/anatomia & histologia , Período Perioperatório , Complicações Pós-Operatórias/etiologia , Estudos Prospectivos , Rinoplastia/efeitos adversos , Rotação , Resultado do Tratamento , Adulto Jovem
15.
Polymers (Basel) ; 10(4)2018 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-30966383

RESUMO

Foams based on polyetherimide (PEI) with carbon nanotubes (CNT) and PEI with graphene nanoplatelets (GnP) combined with CNT were prepared by water vapor induced phase separation. Prior to foaming, variable amounts of only CNT (0.1⁻2.0 wt %) or a combination of GnP (0.0⁻2.0 wt %) and CNT (0.0⁻2.0 wt %) for a total amount of CNT-GnP of 2.0 wt %, were dispersed in a solvent using high power sonication, added to the PEI solution, and intensively mixed. While the addition of increasingly higher amounts of only CNT led to foams with more heterogeneous cellular structures, the incorporation of GnP resulted in foams with finer and more homogeneous cellular structures. GnP in combination with CNT effectively enhanced the thermal stability of foams by delaying thermal decomposition and mechanically-reinforced PEI. The addition of 1.0 wt % GnP in combination with 1.0 wt % CNT resulted in foams with extremely high electrical conductivity, which was related to the formation of an optimum conductive network by physical contact between GnP layers and CNT, enabling their use in electrostatic discharge (ESD) and electromagnetic interference (EMI) shielding applications. The experimental electrical conductivity values of foams containing only CNT fitted well to a percolative conduction model, with a percolation threshold of 0.06 vol % (0.1 wt %) CNT.

16.
Polymers (Basel) ; 11(1)2018 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-30960014

RESUMO

The present work deals with the study of phosphorus flame retardant microcellular acrylonitrile⁻butadiene⁻styrene (ABS) parts and the effects of weight reduction on the fire and mechanical performance. Phosphorus-based flame retardant additives (PFR), aluminum diethylphosphinate and ammonium polyphosphate, were used as a more environmentally friendly alternative to halogenated flame retardants. A 25 wt % of such PFR system was added to the polymer using a co-rotating twin-screw extruder. Subsequently, microcellular parts with 10, 15, and 20% of nominal weight reduction were prepared using a MuCell® injection-molding process. The results indicate that the presence of PFR particles increased the storage modulus and decreased the impact energy determined by means of dynamic-mechanical-thermal analysis and falling weight impact tests respectively. Nevertheless, the reduction of impact energy was found to be lower in ABS/PFR samples than in neat ABS with increasing weight reduction. This effect was attributed to the lower cell sizes and higher cell densities of the microcellular core of ABS/PFR parts. All ABS/PFR foams showed a self-extinguishing behavior under UL-94 burning vertical tests, independently of the weight reduction. Gradual decreases of the second peak of heat release rate and time of combustion with similar intumescent effect were observed with increasing weight reduction under cone calorimeter tests.

17.
Polymers (Basel) ; 10(8)2018 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-30960779

RESUMO

In this study, block and random copolymers of polypropylene⁻ethylene are selected to prepare porous membranes through the melt extrusion-annealing-uniaxial stretching technique (MEAUS), at a constant draw ratio. In some cases, these copolymers were blended with a homopolymer grade. The variation of temperature in the stages of extrusion, annealing and uniaxial strain was analysed. Several characterisation techniques were employed to study this influence. The crystalline orientation was analysed by polarised infrared spectroscopy (FT-IR), and crystalline features were studied by differential scanning calorimetry (DSC). The thermal stability of the membranes was checked by thermogravimetric analysis (TGA). Tensile tests were performed to ascertain the stiffness and ductility of the produced samples. The results were correlated with the porous morphology, global porosity, and permeability to air. A close relationship was found between crystalline characteristics, porous morphology and the trends registered. An improved pore distribution along the membrane surface was found when copolymers were employed.

18.
J Med Microbiol ; 66(1): 70-77, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27902398

RESUMO

Enterobacter aerogenes and Enterobacter cloacae complex are the two species of this genus most involved in healthcare-associated infections that are ESBL and carbapenemase producers. This study characterized, phenotypically and genotypically, 51 isolates of E. aerogenes and E. cloacae complex originating from infection or colonization in patients admitted to a public hospital in Recife, Pernambuco, Brazil, by antimicrobial susceptibility profile, analysis of ß-lactamase genes (blaTEM, blaSHV, blaCTX-M, blaKPC, blaVIM, blaIMP and blaSPM), PCR and DNA sequencing, plasmid profile and ERIC-PCR. In both species, the genes blaTEM, blaCTX-M and blaKPC were detected. The DNA sequencing confirmed the variants blaTEM-1, blaCTX-M-15 and blaKPC-2 in isolates. More than one gene conferring resistance in the isolates, including the detection of the three previously cited genes in strains isolated from infection sites, was observed. The detection of blaCTX-M was more frequent in isolates from infection sites than from colonization. The gene blaKPC predominated in E. cloacae complex isolates obtained from infections; however, in E. aerogenes isolates, it predominated in samples obtained from colonization. A clonal relationship among all of E. aerogenes isolates was detected by ERIC-PCR. The majority of E. cloacae complex isolates presented the same ERIC-PCR pattern. Despite the clonal relation presented by the isolates using ERIC-PCR, different plasmid and resistance profiles and several resistance genes were observed. The clonal dissemination and the accumulation of ß-lactam resistance determinants presented by the isolates demonstrated the ability of E. aerogenes and E. cloacae complex, obtained from colonization and infection, to acquire and maintain different resistance genes.


Assuntos
Proteínas de Bactérias/genética , Enterobacter aerogenes/genética , Enterobacter cloacae/genética , Resistência beta-Lactâmica/genética , beta-Lactamas/farmacologia , Antibacterianos/farmacologia , Técnicas de Tipagem Bacteriana , Brasil , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/microbiologia , DNA Bacteriano/genética , Enterobacter aerogenes/efeitos dos fármacos , Enterobacter cloacae/efeitos dos fármacos , Hospitais Públicos , Humanos , Testes de Sensibilidade Microbiana , Análise de Sequência de DNA , beta-Lactamases/genética
19.
J. Phys. Educ. (Maringá) ; 28(1): e2809, 2017. tab
Artigo em Inglês, Português | LILACS | ID: biblio-954440

RESUMO

ABSTRACT The objective of this study was to understand the perceptions of elementary school leaders in the municipality of Jaguariúna (State of São Paulo, Brazil) about the benefits that combat sports can bring to education in Physical Education classes or as extracurricular activities and the possibilities to enabling this process. Semi-structured interviews were conducted with school directors and coordinators in all 15 public and private schools, totalling 30 interviews. Most of the interviewed had little contact with combat sports and only three had this activity at the school. The interviews were recorded, transcribed, and organized for qualitative textual analysis. The results point out that combat sports are valuable teaching tools in elementary schools, and that in order for their benefits to be achieved, they should be developed following school regular activities, and the professionals must be inserted in the school context. Several benefits were emphasized by the school leaders, including aspects of student attitudes, transmission of values, emotional development, social relations and benefits related to physical activity.


RESUMO O objetivo desse estudo é conhecer a percepção dos dirigentes de escolas do ensino fundamental sobre os potenciais benefícios das Lutas e como viabilizar a inserção dessa prática na escola, nas aulas de Educação Física ou como atividade extracurricular. Entrevistas semiestruturadas foram realizadas com os diretores e coordenadores dos estabelecimentos de ensino de Jaguariúna, interior de São Paulo, que somaram 15 escolas entre públicas e particulares, totalizando 30 entrevistas gravadas e transcritas, constituindo uma matriz para análise textual qualitativa. A maioria dos dirigentes teve pouco contato e apenas três escolas desenvolvem aulas de Lutas, entretanto, verificou-se como principal resultado que essa prática é considerada como possível e bem vista no ambiente escolar. Os dirigentes entendem, sobretudo, que os benefícios estão ligados à capacitação e inserção do profissional no contexto escolar e que devem ser desenvolvidas no contra turno, como complementares às atividades curriculares. Diversos foram os benefícios percebidos pelos dirigentes das escolas, ligados principalmente, aos aspectos de transmissão de condutas e valores, desenvolvimento emocional, relações sociais e benefícios relacionados à atividade física.


Assuntos
Humanos , Exercício Físico , Estudos de Avaliação como Assunto , Entrevista , Meio Ambiente
20.
Rev. bras. ciênc. esporte ; 38(4): 376-383, out.-dez. 2016. tab
Artigo em Português | LILACS | ID: biblio-829772

RESUMO

Resumo O objetivo deste artigo é analisar as percepções que os professores polivalentes do 1º ao 5ª ano do ensino fundamental têm sobre a educação física como componente curricular. A metodologia usada foi uma pesquisa de campo com a aplicação de questionários em 16 escolas de Jacarepaguá, na Zona Oeste do Rio de Janeiro (RJ). A amostra compreendeu 154 professores polivalentes. Concluímos que houve um avanço qualitativo na percepção dos professores polivalentes sobre a educação física. Entretanto, ainda existe um desconhecimento sobre seus objetivos e suas finalidades. Apontamos a necessidade de elaboração de acordos mínimos para a intervenção na escola.


Abstract The objective of this paper is to analyze the perceptions that polyvalent teachers from 1st to 5th year have on physical education as a curriculum component. The methodology used was a field survey with questionnaires in sixteen schools Jacarepagua. The sample consisted of 154 multipurpose teachers in total. At the end, we concluded that there was a qualitative improvement in the perception of polyvalent teachers on physical education. However, there is still a lack of knowledge about its goals and purposes. Pointed out the need for construction of minimum arrangements for intervention in school.


Resumen El objetivo de este trabajo es analizar las percepciones que los maestros polivalentes de 1.º a 5.º curso tienen sobre la educación física como componente curricular. La metodología usada fue un estudio de campo con cuestionarios en 16 escuelas de Jacarepaguá. La muestra en total estaba formada por 154 profesores polivalentes. Al final, se llegó a la conclusión de que había una mejora cualitativa en la percepción de los maestros polivalentes sobre la educación física. Sin embargo, todavía hay una falta de conocimiento acerca de sus objetivos y propósitos. Se señaló la necesidad de construcción de acuerdos mínimos para la intervención en la escuela.

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