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1.
Materials (Basel) ; 14(21)2021 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-34771831

RESUMO

The present study investigates, experimentally and numerically, the tensile behavior of copper-clad aluminum composite wires. Two fiber-matrix configurations, the conventional Al-core/Cu-case and a so-called architectured wire with a continuous copper network across the cross-section, were considered. Two different fiber arrangements with 61 or 22 aluminum fibers were employed for the architectured samples. Experimentally, tensile tests on the two types of composites show that the flow stress of architectured configurations is markedly higher than that of the linear rule of mixtures' prediction. Transverse stress components and processing-induced residual stresses are then studied via numerical simulations to assess their potential effect on this enhanced strength. A set of elastic-domain and elastoplastic simulations were performed to account for the influence of Young's modulus and volume fraction of each phase on the magnitude of transverse stresses and how theses stresses contribute to the axial stress-strain behavior. Besides, residual stress fields of different magnitude with literature-based distributions expected for cold-drawn wires were defined. The findings suggest that the improved yield strength of architectured Cu-Al wires cannot be attributed to the weak transverse stresses developed during tensile testing, while there are compelling implications regarding the strengthening effect originating from the residual stress profile. Finally, the results are discussed and concluded with a focus on the role of architecture and residual stresses.

2.
Ecol Evol ; 11(8): 3516-3526, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33898007

RESUMO

Learning biology, and in particular systematics, requires learning a substantial amount of specific vocabulary, both for botanical and zoological studies. While crucial, the precise identification of structures serving as evolutionary traits and systematic criteria is not per se a highly motivating task for students. Teaching this in a traditional teaching setting is quite challenging especially with a large crowd of students to be kept engaged. This is even more difficult if, as during the COVID-19 crisis, students are not allowed to access laboratories for hands-on observation on fresh specimens and sometimes restricted to short-range movements outside their home. Here, we present QuoVidi, a new open-source web platform for the organization of large-scale treasure hunts. The platform works as follows: students, organized in teams, receive a list of quests that contain morphologic, ecologic, or systematic terms. They have to first understand the meaning of the quests, then go and find them in the environment. Once they find the organism corresponding to a quest, they upload a geotagged picture of their finding and submit this on the platform. The correctness of each submission is evaluated by the staff. During the COVID-19 lockdown, previously validated pictures were also submitted for evaluation to students that were locked in low-biodiversity areas. From a research perspective, the system enables the creation of large image databases by the students, similar to citizen science projects. Beside the enhanced motivation of students to learn the vocabulary and perform observations on self-found specimens, this system allows instructors to remotely follow and assess the work performed by large numbers of students. The interface is freely available, open-source and customizable. Unlike existing naturalist platforms, allows the educators to fully customize the quests of interest. This enables the creation of multiple teaching scenarios, without being bound to a fixed scope. QuoVidi can be used in other disciplines with adapted quests and we expect it to be of interest in many classroom settings.

3.
Caries Res ; 54(2): 154-164, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32101874

RESUMO

This prospective cohort study investigated the distribution pattern of carious lesions diagnosed by visual tactile and radiographic examinations, assessed the radiographic yield for clinical caries diagnosis, and estimated how accurately commonly used indicators for caries identified young adults who would benefit from radiographs at different thresholds. Overall, 576 patients aged 16-32 years seeking a first consultation were included. Patients were examined for caries and answered a validated questionnaire on sociodemographics and oral health behavior. Almost 10% of clinically sound approximal surfaces presented radiolucency in enamel/dentine. Of the clinically diagnosed noncavitated approximal and occlusal lesions, 22.5 and 17.7%, respectively, presented radiolucency reaching dentine at the radiographic examination. Noncavitated/enamel lesions detected radiographically were mainly at approximal surfaces (73.2%), while at occlusal surfaces these were negligible (0.7%). More than half of approximal dentine lesions were only detected radiographically (61.3%), while more than half of occlusal dentine lesions were only clinically diagnosed (57.1%). The hierarchical logistic regression analysis showed that patient's caries activity, D1MFS scores ≥17, and frequent consumption of soft drinks were significantly associated with detection of approximal enamel/dentine lesions. Also, patient's caries activity and frequent consumption of soft drinks were significantly associated with occlusal dentine caries (p ≤ 0.05). The indicator power of grouping these indicators as a predictor for the presence of radiographically detected lesions showed high sensitivity (0.84-0.91) and moderate specificity (0.64-0.73) for all surfaces and thresholds tested. In conclusion, radiographs increased significantly the number of approximal enamel/dentine and occlusal dentine lesions diagnosed. The ability to identify young adults with approximal lesions from the predictor was satisfactory. Bearing in mind that an essential contribution of bitewing radiographs to clinical examination is the detection of approximal noncavitated/enamel lesions that can be inactivated by nonoperative interventions, our results support the prescription of radiographs in young adults seeking a first consultation. Updating of current guidelines' recommendation of radiographs is warranted.


Assuntos
Cárie Dentária , Adolescente , Adulto , Cárie Dentária/diagnóstico por imagem , Esmalte Dentário/diagnóstico por imagem , Dentina/diagnóstico por imagem , Diagnóstico Bucal , Humanos , Estudos Prospectivos , Radiografia Interproximal , Adulto Jovem
4.
BMJ Paediatr Open ; 3(1): e000547, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31646199

RESUMO

BACKGROUND: Paediatric complex chronic conditions (CCCs) are life-limiting conditions requiring paediatric palliative care, which, in Belgium, is provided through paediatric liaison teams (PLTs). Like the number of children and adolescents with these conditions in Belgium, their referral to PLTs is unknown. OBJECTIVES: The aim of the study was to identify, over a 5-year period (2010-2014), the number of children and adolescents (0-19 years) living with a CCC, and also their referral to PLTs. METHODS: International Classification of Disease codes (ICD-9) corresponding to a CCC, as described by Feudtner et al, and national registration numbers were extracted from the databases of all hospitals (n=8) and PLTs (n=2) based in the Brussels region. Aggregated data and pseudonymised national registration number were transmitted to the research team by a Trusted Third Party (eHealth). Ages and diagnostic categories were calculated using descriptive statistics. RESULTS: Over 5 years (2010-2014) in the Brussels region, a total of 22 721 children/adolescents aged 0-19 years were diagnosed with a CCC. Of this number, 22 533 were identified through hospital registries and 572 through PLT registries. By comparing the registries, we found that of the 22 533 children/adolescents admitted to hospital, only 384 (1.7%) were also referred to a PLT. CONCLUSION: In Belgium, there may be too few referrals of children and adolescents with CCC to PLTs that ensure continuity of care.

5.
PLoS One ; 10(12): e0145497, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26693908

RESUMO

Brain blood barrier breakdown as assessed by contrast-enhanced (CE) T1-weighted MR imaging is currently the standard radiological marker of inflammatory activity in multiple sclerosis (MS) patients. Our objective was to evaluate the performance of an alternative model assessing the inflammatory activity of MS lesions by texture analysis of T2-weighted MR images. Twenty-one patients with definite MS were examined on the same 3.0T MR system by T2-weighted, FLAIR, diffusion-weighted and CE-T1 sequences. Lesions and mirrored contralateral areas within the normal appearing white matter (NAWM) were characterized by texture parameters computed from the gray level co-occurrence and run length matrices, and by the apparent diffusion coefficient (ADC). Statistical differences between MS lesions and NAWM were analyzed. ROC analysis and leave-one-out cross-validation were performed to evaluate the performance of individual parameters, and multi-parametric models using linear discriminant analysis (LDA), partial least squares (PLS) and logistic regression (LR) in the identification of CE lesions. ADC and all but one texture parameter were significantly different within white matter lesions compared to within NAWM (p < 0.0167). Using LDA, an 8-texture parameter model identified CE lesions with a sensitivity Se = 70% and a specificity Sp = 76%. Using LR, a 10-texture parameter model performed better with Se = 86% / Sp = 84%. Using PLS, a 6-texture parameter model achieved the highest accuracy with Se = 88% / Sp = 81%. Texture parameter from T2-weighted images can assess brain inflammatory activity with sufficient accuracy to be considered as a potential alternative to enhancement on CE T1-weighted images.


Assuntos
Encéfalo/diagnóstico por imagem , Inflamação/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Esclerose Múltipla/patologia , Barreira Hematoencefálica , Encéfalo/patologia , Humanos , Inflamação/patologia , Esclerose Múltipla/diagnóstico por imagem , Reconhecimento Automatizado de Padrão , Curva ROC , Intensificação de Imagem Radiográfica/métodos
6.
Caries Res ; 48(6): 515-23, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24902889

RESUMO

The study aimed at identifying oral health determinants that are present in early childhood, are amenable to change and for which there is evidence of their modulation of the rate of caries progression in a sample of non-privileged children. The null hypothesis was that determinants associated with the child's institutional environment as evidenced by nursery policies significantly influenced the child's oral health. The sample was formed by 2,511 Brazilian 1-5-year-olds. Caries severity and activity were recorded. Parents were interviewed and nurseries answered a questionnaire. According to the case status d1efs, the final multilevel model (generalized linear mixed model) identified significant associations with determinants such as bottle-feeding the child during the night on demand, not assisting the child in toothbrushing, ensuring visit to the dentist in case of troubles with teeth only (p < 0.0001) and intake of sugary products 2-4 times daily at nursery (p = 0.026). The likelihood of caries outcomes was associated with determinants related to nursery policies, not promoting preventive oral health care for children of mothers with 4 years of education (OR = 2.14; p < 0.0015) and <4 years of education (OR = 2.6; p = 0.0010), as well as consumption of sugary products 2-4 times daily for children of mothers with 4 years of education (OR = 3.35; p = 0.0010) and <4 years of education (OR = 4.07; p = 0.0063). In conclusion, determinants related to parental negative practices and to nursery policies significantly influenced children's oral health. Of particular interest was the identification of determinants considered amenable to change in connection with nursery policies towards oral health.


Assuntos
Cárie Dentária/epidemiologia , Saúde Bucal , Determinantes Sociais da Saúde , Populações Vulneráveis/estatística & dados numéricos , Adolescente , Adulto , Alimentação com Mamadeira/estatística & dados numéricos , Brasil/epidemiologia , Creches/organização & administração , Pré-Escolar , Índice CPO , Assistência Odontológica/estatística & dados numéricos , Sacarose Alimentar/administração & dosagem , Escolaridade , Feminino , Comportamentos Relacionados com a Saúde , Política de Saúde , Humanos , Renda/estatística & dados numéricos , Lactente , Masculino , Idade Materna , Mães/educação , Poder Familiar , Escolas Maternais/organização & administração , Escovação Dentária/estatística & dados numéricos , Adulto Jovem
7.
Langmuir ; 29(13): 4388-95, 2013 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-23480273

RESUMO

Hybridization of polyoxometalates (POMs) via the formation of an organic-inorganic association constitutes a new route to develop a heterogeneous POM catalyst with tunable functionality imparted through supramolecular assembly. Herein, we report on strategies to obtain tunable well-defined supramolecular architectures of an organic-inorganic heterogeneous hybrid catalyst formed by the association of a hydrophobically substituted polyampholyte copolymer (poly N, N-diallyl-N-hexylamine-alt-maleic acid) and phosphotungstic acid (H3PW12O40) POMs. The self-assembling property of the initial polyampholyte copolymer matrix is modulated by controlling the pH of the hybridization solution. When deposited on a mica surface, isolated, long and extended polymer chains are formed under basic conditions (pH 7.9), while globular or coiled structures are formed under acidic conditions (pH 2). The supramolecular assembly of the POM-polymer hybrid is found to be directed by the type and quantities of charges present on the polyampholyte copolymer, which themselves depend on the pH conditions. The hypothesis is that the Keggin type [PW12O40](3-) anions, which have a size of ~1 nm, electrostatically bind to the positive charge sites of the polymer backbone. The hybrid material stabilized at pH 5.3 consists of POM-decorated polymer chains. Statistical analysis of distances between pairs of POM entities show narrow density distributions, suggesting that POM entities are attached to the polymer chains with a high level of order. Conversely, under acidic conditions (pH 2), the hybrid shows the formation of a core-shell type of structure. The strategies reported here, to tune the supramolecular assembly of organic-inorganic hybrid materials, are highly valuable for the design and a more rational utilization of POM heterogeneous catalysts in several chemical transformations.


Assuntos
Polímeros/química , Catálise , Substâncias Macromoleculares/síntese química , Substâncias Macromoleculares/química , Modelos Moleculares , Estrutura Molecular , Tamanho da Partícula , Polímeros/síntese química , Propriedades de Superfície
8.
Mycorrhiza ; 21(5): 443-449, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21553021

RESUMO

The vegetative compatibility of the arbuscular mycorrhizal fungus (AMF) Glomus clarum MUCL 46238 was evaluated after continuous exposure to fenhexamid, a sterol biosynthesis inhibitor (SBI). Three lineages of this AMF were cultured in vitro for five generations in association with Ri T-DNA transformed carrot roots in the presence of 0, 5 or 10 mg l(-1) of fenhexamid. Whatever the AMF generation, fenhexamid at 5 and 10 mg l(-1) had no significant impact on the number of spores produced. However, vegetative compatibility tests (VCT) conducted with spores from the three lineages, in the presence of 10 mg l(-1) of fenhexamid, impacted the anastomosis process. At this concentration, the morphology of the germ tubes was modified. In addition, nitrotetrazolium-trypan blue staining revealed that 10 mg l(-l) of fenhexamid significantly reduced the probability of fusion between the germ tubes regardless of the culture conditions (i.e. absence or presence of fenhexamid) preceding the VCT. Our results demonstrated that spore production was not affected by fenhexamid, while anastomosis between germ tubes was decreased. This suggested that high concentrations, accumulation or repeated application of this SBI fungicide may impact the community structure of AMF in soil.


Assuntos
Amidas/farmacologia , Glomeromycota/efeitos dos fármacos , Glomeromycota/crescimento & desenvolvimento , Esteróis/antagonistas & inibidores , Esteróis/biossíntese , Fungicidas Industriais/farmacologia , Glomeromycota/metabolismo , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/metabolismo
9.
Gynecol Obstet Invest ; 65(3): 174-86, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18025832

RESUMO

BACKGROUND: In vitro studies suggest that the transcription factor nuclear factor-kappa B (NF-kappaB) is implicated in the transduction of proinflammatory signals in endometriosis. The aim of this study was to investigate the involvement of NF-kappaB and the processes regulated by NF-kappaB in the initial development of endometriotic lesionsin vivo. METHODS: Endometriosis was induced in nude mice by intraperitoneal injection of fluorescent-labeled menstrual endometrium. Two NF-kappaB inhibitors (BAY 11-7085 and SN-50) were injected intraperitoneally on days 0, 2 and 4 after endometriosis induction, and endometriotic lesions were recovered on day 5. Number, mass, fluorimetry and surface (morphometry) of endometriotic lesions were quantified. NF-kappaB activation, intercellular adhesion molecule (ICAM)-1 expression, cell proliferation and apoptosis were evaluated by immunohistochemical analyses and the TUNEL method. RESULTS: Both NF-kappaB inhibitors induced a significant reduction in lesion development compared to control mice. NF-kappaB activation and ICAM-1 expression of endometriotic lesions were significantly reduced in treated mice, and cell proliferation was significantly reduced in BAY 11-7085-treated mice. Both inhibitors produced a significant increase in apoptosis of endometriotic lesions, as assessed by active caspase-3 immunostaining and the TUNEL method. CONCLUSION: This study demonstrates, for the first time, that the NF-kappaB pathway is implicated in the development of endometriotic lesions in vivo and that NF-kappaB inhibition reduces ICAM-1 expression and cell proliferation, but increases apoptosis of endometriotic lesions, diminishing the initial development of endometriosis in an animal model.


Assuntos
Endometriose/tratamento farmacológico , Inibidores Enzimáticos/uso terapêutico , NF-kappa B/antagonistas & inibidores , Nitrilas/uso terapêutico , Peptídeos/uso terapêutico , Sulfonas/uso terapêutico , Animais , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Endometriose/etiologia , Feminino , Humanos , Molécula 1 de Adesão Intercelular/biossíntese , Camundongos , Camundongos Nus
10.
Soc Psychiatry Psychiatr Epidemiol ; 42(5): 360-5, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17396204

RESUMO

BACKGROUND: Psychiatric commitment laws have been reformed in many European countries. We assessed the relative importance of the different legal criteria in explaining involuntary commitment under the Belgian Mental Health Act of 1990. METHOD: Psychiatric assessments were requested for 346 patients living in Brussels who were randomly selected from a larger group and were being considered for involuntary commitment. A retrospective study of these patients' files was carried out. RESULTS: More than half of the requests for involuntary commitment were turned down. The lack of a less restrictive alternative form of care was the criterion most crucial in decisions in favour of commitment. Alternative forms of care were more likely to be unavailable for psychotic individuals, foreigners, and patients not living in a private household. CONCLUSION: Involuntary commitment is mainly due to the inability of the mental health care system to provide more demanding patients with alternative forms of care.


Assuntos
Internação Compulsória de Doente Mental/legislação & jurisprudência , Tomada de Decisões Gerenciais , Serviços de Saúde Mental/legislação & jurisprudência , Psiquiatria/legislação & jurisprudência , Adulto , Bélgica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Saúde Pública
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