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Silva S, Barbosa JM, Sousa JD, Paiva MC, Teixeira PF. High-Performance PEEK/MWCNT Nanocomposites: Combining Enhanced Electrical Conductivity and Nanotube Dispersion. Polymers (Basel) 2024; 16:583. [PMID: 38475267 DOI: 10.3390/polym16050583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 02/15/2024] [Accepted: 02/17/2024] [Indexed: 03/14/2024] Open
Abstract
High-performance engineering thermoplastics offer lightweight and excellent mechanical performance in a wide temperature range. Their composites with carbon nanotubes are expected to enhance mechanical performance, while providing thermal and electrical conductivity. These are interesting attributes that may endow additional functionalities to the nanocomposites. The present work investigates the optimal conditions to prepare polyether ether ketone (PEEK)/multi-walled carbon nanotube (MWCNT) nanocomposites, minimizing the MWCNT agglomerate size while maximizing the nanocomposite electrical conductivity. The aim is to achieve PEEK/MWCNT nanocomposites that are suitable for melt-spinning of electrically conductive multifilament's. Nanocomposites were prepared with compositions ranging from 0.5 to 7 wt.% MWCNT, showing an electrical percolation threshold between 1 and 2 wt.% MWCNT (107-102 S/cm) and a rheological percolation in the same range (1 to 2 wt.% MWCNT), confirming the formation of an MWCNT network in the nanocomposite. Considering the large drop in electrical conductivity typically observed during melt-spinning and the drawing of filaments, the composition PEEK/5 wt.% MWCNT was selected for further investigation. The effect of the melt extrusion parameters, namely screw speed, temperature, and throughput, was studied by evaluating the morphology of MWCNT agglomerates, the nanocomposite rheology, and electrical properties. It was observed that the combination of the higher values of screw speed and temperature profile leads to the smaller number of MWCNT agglomerates with smaller size, albeit at a slightly lower electrical conductivity. Generally, all processing conditions tested yielded nanocomposites with electrical conductivity in the range of 0.50-0.85 S/cm. The nanocomposite processed at higher temperature and screw speed presented the lowest value of elastic modulus, perhaps owing to higher matrix degradation and lower connectivity between the agglomerates. From all the process parameters studied, the screw speed was identified to have the higher impact on nanocomposite properties.
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Affiliation(s)
- Sofia Silva
- CeNTI-Centre for Nanotechnology and Smart Materials, R. Fernando Mesquita 2785, 4760-034 Vila Nova de Famalicão, Portugal
| | - José M Barbosa
- CeNTI-Centre for Nanotechnology and Smart Materials, R. Fernando Mesquita 2785, 4760-034 Vila Nova de Famalicão, Portugal
| | - João D Sousa
- CeNTI-Centre for Nanotechnology and Smart Materials, R. Fernando Mesquita 2785, 4760-034 Vila Nova de Famalicão, Portugal
| | - Maria C Paiva
- Department of Polymer Engineering, Institute for Polymers and Composites, University of Minho, 4800-058 Guimarães, Portugal
| | - Paulo F Teixeira
- CeNTI-Centre for Nanotechnology and Smart Materials, R. Fernando Mesquita 2785, 4760-034 Vila Nova de Famalicão, Portugal
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Abstract
Epithelioid haemangioendothelioma (EHE) is a rare tumour of vascular origin, characterised by celular proliferation, endotelial, epitelioid or hystiocitoid. It may develop in any organ, but it is more common in lung and liver. Surgery is the recommended treatment; however, in case of a potentially benign situation, an expectant attitude should be adopted. The case reports a 71-year-old female who underwent a laparotomy for a colonic adenocarcinoma. During surgery, a polypoid lesion in the dependency of the gastric wall was found incidentally, which was removed. Histopathology and immunohistochemical analysis confirmed the diagnosis of EHE. Gastric vascular neoplasms represent about 0.9-3.3% of all gastric tumours. Usually have a good prognosis, but due to the borderline biological behaviour of these tumours, it is important to have a detailed clinical evaluation at follow-up of these patients.
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Affiliation(s)
- A B Tavares
- Centro Hospitalar de Vila Nova de Gaia/Espinho, Vila Nova de Gaia, Portugal.
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Barbosa JM, Volpato GL. Chemical modulation on heterogeneous growth in Prochilodus lineatus (Valenciennes, 1847) (Pisces; Characiformes). BRAZ J BIOL 2007; 67:147-51. [PMID: 17505762 DOI: 10.1590/s1519-69842007000100020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2005] [Accepted: 02/28/2007] [Indexed: 05/15/2023] Open
Abstract
In the present study, the effect of chemical factors released by conspecifics on growth variability (heterogeneous growth - HetG) in a gregarious fish species (Prochilodus lineatus) was tested. HetG was assessed by the weight variation coefficient in two consecutive 21-day periods. The fish were grouped in tanks (4 fish in each) that received running water with constant draining. The tanks contained either conspecifics (C) or non-conspecifics (N). Four conditions were established in accordance with the tank water supply: a) water with previous contact with conspecifics throughout the experiment (CC); b) water without previous contact with conspecifics throughout the experiment (NN); c) water with previous contact with conspecifics in just the first period, 0 to 21 days (CN); and d) just in the period from 21 to 42 days (NC). At the end of the experiments, the occurrence of chemical modulation on the growth variability in P. lineatus was verified: the fish that received water with previous contact with a conspecific (C) presented exacerbation of HetG. This corroborates the notion that the predominant mechanism in the determination of intraspecific growth variation in the gregarious species is associated to chemical factors released by conspecifics.
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Affiliation(s)
- J M Barbosa
- Departamento de Pesca e Aqüicultura, Universidade Federal Rural de Pernambuco, Recife, PE, Brazil.
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Barbosa JM, Brugiolo SSS, Carolsfeld J, Leitão SS. Heterogeneous growth fingerlings of the Nile tilapia Oreochromis niloticus: effects of density and initial size variability. BRAZ J BIOL 2006; 66:537-41. [PMID: 16862309 DOI: 10.1590/s1519-69842006000300020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2004] [Accepted: 12/06/2004] [Indexed: 11/22/2022] Open
Abstract
In this study, the effect of initial heterogeneity of weight and density on heterogeneous growth (HetG) evaluated by the coefficient of the variation of weight in the young Nile tilapia Oreochromis niloticus of the territorial species was tested. Fish were maintained in a glass aquarium (8 and 2 L of water) with two levels of initial heterogeneity of weight: low and high, under two density conditions: low and high, thus constituting four conditions (six replications for each). Initially, the weights of the animals were taken after 8, 16, 22 and 30 days (end of experiment). The results, evaluated by the non-parametric test of Kruskal- Wallis, demonstrated that in the groups where the animals were stored under high initial HetG, there was a reduction of the same and that in the groups where the animals were stored under high density, there was exacerbation or maintained high values of HetG. High density in association with high initial heterogeneity caused more exacerbation of HetG in such a way that the density appeared to be a determining factor for exacerbation or the maintenance of high values of HetG, whereas the initial heterogeneity of the weight could be a secondary factor.
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Affiliation(s)
- J M Barbosa
- Departamento de Pesca e Aqüicultura, Universidade Federal Rural de Pernambuco, Recife, PE, Brazil
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Abstract
Most of the clinical, histological and immunohistological features of fogo selvagem resemble those of idiopathic pemphigus foliaceus (PF). Both diseases are clinically characterized by small flaccid bullae evolving into to scaly and crusted lesions, sometimes with pustules, mainly in seborrheic areas of the skin. Mucosal surfaces are mostly spared. The main histologic feature of endemic pemphigus foliaceus is a subcorneal acantholytic blister. Standard immunofluorescence studies demonstrate intercellular IgG deposits throughout the entire epidermis. These IgG antibodies are mainly of the IgG4-subclass. Almost all patients have circulating IgG-autoantibodies in their serum directed against stratified epithelial desmosomes. The fogo selvagem autoantibodies and the PF antibodies are directed against the 160 kD desmosomal glycoprotein desmoglein 1 which together with plakoglobin (85 kD) forms a complex of adhesion proteins with desmosomes of stratified epithelia. Fogo selvagem occurs in endemic foci in some areas of Brazil and possibly in neighbouring South American countries, very often in children, adolescents and young adults. The etiology of fogo selvagem is still unknown. The frequent association with insect bites has lead to the concept of fogo selvagem being a transmissible disease with acquired immunity in adulthood. However, the infectious agent and possible vectors have not yet been identified.
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Affiliation(s)
- C Kunte
- Dermatologische Klinik und Poliklinik, Ludwig-Maximilians-Universität München
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Zimmermann AF, de Messias IJ, Utiyama SR, Chiu YY, Nisihara RM, Moura ML, Barbosa JM. Clinical, autoimmune and demographic profile in systemic lupus erythematosus (SLE) patients from southern Brazil. J Investig Allergol Clin Immunol 1997; 7:24-31. [PMID: 9093930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
With the purpose of determining the association of clinical, autoimmune and demographic features, a group of 90 SLE patients from Southern Brazil were investigated. At diagnosis, 24% of them were under 20 years, 63% were between 20 and 40 years and 13% were older than 40 years. According to the ethnic background, there were 66% Brazilian-white patients, 21% Caucasians and 13% Mullatos/Blacks. Antinuclear antibodies (ANA) were present in 98%, anti-ds-DNA in 56% and anti-Sm in 31% of the patients. Anti-ds-DNA were more prevalent in the Caucasians (79%), while anti-Sm were increased in the Mullatos/Blacks (58%, p < 0.02) as compared to the white patients (Brazilian-whites = 22% and Caucasians = 42%). Neurologic involvement had lower prevalence in the group of Mullato/Black patients (8%) than in the Brazilian-whites (32%) and Caucasians (31%). Serositis was present in 51% of the Brazilian-whites, in 21% of the Caucasians and in 41% of the Mullatos/Blacks. On the other hand, the Mullato/ Black group had an increased prevalence of vasculitis (50%) and none of them presented with Raynaud's phenomenon. Younger patients at diagnosis presented higher frequency of renal involvement (p < 0.05), anti-ds-DNA positivity (p < 0.02) and more severe disease (p < 0.07), and in those patients diagnosed after age 40, 33% presented with Raynaud's phenomenon (p < 0.05). Regarding the anti-ds-DNA positivity, 78% of the patients had renal involvement (p < 0.01 RR 2.2) and 66% severe disease (p < 0.05). These results might be important in assessing clinical subsets and may aid individualized management of Brazilian SLE patients. Also, they may corroborate the need for special attention to racial composition in clinical and immunogenetic studies.
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Affiliation(s)
- A F Zimmermann
- Departamento de Patología Médica, Hospital de Clínicas da Universidade Federal do Paraná
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da Silva MA, Costa JM, Barbosa JM, Cabral F, Fragata Filho AA, Correa EB, Borges Filho R, Sousa JE. [Chronic phase of Chagas disease. Clinical aspects and course of the disease]. Arq Bras Cardiol 1994; 63:281-5. [PMID: 7771944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
PURPOSE To evaluate the clinical and evolutive aspects of chronic chagasic patients. METHODS Three hundred chronic chagasic patients, 180 females, with age ranging from 19 to 81 years (55.6 +/- 13.1) were retrospectively studied. Patients were divided according to the following clinical types: indeterminated, cardiac (with the subtypes: arrhythmogenic, dilated and mixed), digestive isolated and digestive plus cardiac involvement. The following variables were analysed: prevalence of each clinical forms, symptoms, electrocardiographic pattern and clinical outcome. RESULTS At the start of the study, 73 (24.3%) patients were in indetermined type, 106 (35.3%) in cardiac arrhythmogenic, 95 (31.6%) in mixed, 7 (2.3%) in dilated, 16 (5.3%) in digestive plus cardiac type and 3 (1%) in the pure digestive type. The most prevalent symptoms were dyspnea on efforts (57%), palpitations (41.33%) and chest pain (33%). The most frequent electrocardiographic pattern was right bundle branch block plus antero-superior fascicular block, in 30% of the patients. The average follow-up time was 7.8 +/- 6.1 years and the outcome was considered good in 20 patients (6.6%), stable in 214 (71.3%) and bad in 66 (23%). At the end of the follow-up, 9 patients have evaluated from the indeterminated to the cardiac and digestive types, and 19 (17.92%), from the arrhythmogenic to mixed cardiac subtype. The follow-up was lost in 79 patients (26.3%), most of them, probably dead. CONCLUSION With a mean time of 7.8 years, 12.3% of the patients in the indeterminated type evolved to the cardiac and/or digestive type; right brundle branch block with antero-superior fascicular block was the most prevalent electrocardiographic pattern; the outcome was stable or good in the majority of these patients.
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Affiliation(s)
- M A da Silva
- Instituto Dante Pazzanese de Cardiologia, São Paulo
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Robinson GE, Strambi A, Strambi C, Paulino-Simões ZL, Tozeto SO, Barbosa JM. Juvenile hormone titers in European and Africanized honey bees in Brazil. Gen Comp Endocrinol 1987; 66:457-9. [PMID: 3609717 DOI: 10.1016/0016-6480(87)90258-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Coutinho EM, Mello DA, Barbosa JM. [Pathology of experimental infection in domestic rodents using various strains of Yersinia pestis]. Mem Inst Oswaldo Cruz 1980; 75:53-62. [PMID: 7348290 DOI: 10.1590/s0074-02761980000200006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Os autores estudaram 253 ratos domésticos (Rattus norvegicus e Rattus r. frugivorus), infectados experimentalmente (via subcutânea) com duas cepas de Yersinia pestis (cepas "PEXU-19" e "RANGEL"), isoladas de roedores silvestres capturados no nordeste brasileiro (Exú - Pernambuco) e na Venezuela, respectivamente, as quais foram mantidas em meio de cultura e subinoculadas periodicamente. A sobrevida dos animais infectados variou de dois a sete dias, sendo os sobreviventes sacrificados no 20º dia após a data da inoculação. Para cada uma das duas espécies de rato, foram empregadas cargas infectantes de intensidades diferentes (750 - 4.250; 7.500 - 41.250 e 75.000 - 750.000 bacilos), correspondentes a cada uma das duas cepas de Y. pestis utilizadas. A patologia foi estudada em relação ao fígado, baço, pulmão e linfonodo inguinal, órgãos onde as lesões se mostraram mais exuberantes. As lesões hepáticas foram essencialmente representadas por congestão, necrose coagulativa multifocal e infiltração inflamatória aguda portal e sinusoidal, com formação de microabscessos. No baço ocorreu atrofia acentuada dos folículos linfóides de Malpighi, congestão, hemorragia e esplemite aguda abscedada. No pulmão, foi achado freqüente a pneumonite aguda, ás vezes acompanhada de abscessos. De um modo geral, a cepa PEXU-19 revelou maior poder patogênico que a cepa RANGEL, embora, em relação à espécie de roedor infectado não tenha sido possível surpreender diferenças quanto á sua susceptibilidade frente ás duas cepas Y. pestis utilizadas no presente trabalho.
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Abath GM, Coutinho-Abath E, Barbosa JM. Histopathology of skeletal muscle in experimental Chagas' disease. II. Alterations in late phase and in combined infection with Schistosoma mansoni. Am J Trop Med Hyg 1966; 15:141-5. [PMID: 4956229 DOI: 10.4269/ajtmh.1966.15.141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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Coutinho-Abath E, Barbosa JM, Amaral JA. [Biochemical changes in human mansonic schistosomiasis, with special reference to lipid metabolism]. Rev Bras Malariol Doencas Trop 1965; 17:293-307. [PMID: 5887886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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Coutinho-Abath E, Espírito Santo M, Barbosa JM, Mello SA. [Alimentary patterns in the endemic areas of Manson's schistosomiasis in the northeast of Brazil]. Rev Bras Malariol Doencas Trop 1964; 16:553-89. [PMID: 5852000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Barbosa JM. Sur la Structure du Poumon du Dauphin (Delphinus delphis). J Anat Physiol 1916; 50:285-92. [PMID: 17233067 PMCID: PMC1289050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
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