Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
Mais filtros








Intervalo de ano de publicação
1.
Sensors (Basel) ; 22(15)2022 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-35957191

RESUMO

In this paper, a dual-band graphene coplanar waveguide antenna is designed for smart cities and internet of things applications. A graphene film is chosen as the conductive material for the radiation patches and ground plane with a thickness of 240 µm and an electric conductivity of 3.5 × 105 S/m. The dielectric is glass with a dielectric permittivity of 6 and a thickness of 2 mm. The implementation of the antenna on glass permits the integration of the antenna in smart cities and IoT applications. This antenna is based on two trapezoidal patches that generate the dual-band behavior. The overall dimensions of the antenna are 30 mm × 30 mm × 2 mm. The reflection coefficient, gain, and radiation patterns were measured and compared with the simulations. The antenna covers two frequency bands; the lower band covers the 2.45 GHz ISM band, and the upper band range covers from 4 to 7 GHz.

2.
J Food Sci Technol ; 57(7): 2758-2763, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32549626

RESUMO

The dielectric properties of litchi fruit were determined using the open-ended coaxial probe method. The measurements were performed in the frequency range from 0.5 to 20 GHz during 3 days of storage at room temperature (~  24 °C). The dielectric properties increased with storage time. Additionally, measurements at different temperatures (24, 30, 40 and 50 °C) were determined. The dielectric constant (ε') decreased with increasing temperature in a frequency range of 0.5-5 GHz; at higher frequencies, ε' increased with increasing temperature. The loss factor (ε″) value increased at frequencies higher than 2 GHz and decreased with increasing temperature. The results will be useful for further applications using microwaves, such as microwave-assisted drying, sensing of quality parameters, modeling, and heating to protect against molds or insects, among other applications.

3.
Res. Biomed. Eng. (Online) ; 32(2): 176-198, Apr.-June 2016. tab, graf
Artigo em Inglês | LILACS | ID: biblio-829477

RESUMO

Abstract Introduction: Due to the increasing popularization of computers and the internet expansion, Alternative and Augmentative Communication technologies have been employed to restore the ability to communicate of people with aphasia and tetraplegia. Virtual keyboards are one of the most primitive mechanisms for alternatively entering text and play a very important role in accomplishing this task. However, the text entry for this kind of keyboard is much slower than entering information through their physical counterparts. Many techniques and layouts have been proposed to improve the typing performance of virtual keyboards, each one concerning a different issue or solving a specific problem. However, not all of them are suitable to assist seriously people with motor impairment. Methods: In order to develop an assistive virtual keyboard with improved typing performance, we performed a systematic review on scientific databases. Results: We found 250 related papers and 52 of them were selected to compose. After that, we identified eight essentials virtual keyboard features, five methods to optimize data entry performance and five metrics to assess typing performance. Conclusion: Based on this review, we introduce a concept of an assistive, optimized, compact and adaptive virtual keyboard that gathers a set of suitable techniques such as: a new ambiguous keyboard layout, disambiguation algorithms, dynamic scan techniques, static text prediction of letters and words and, finally, the use of phonetic and similarity algorithms to reduce the user's typing error rate.

4.
Res. Biomed. Eng. (Online) ; 31(3): 257-272, July-Sept. 2015. tab, graf
Artigo em Inglês | LILACS | ID: biblio-829439

RESUMO

AbstractIntroductionLocked-In Syndrome is admittedly the worst case of motor and speech impairment, it seriously damages the ability of oral and gestural communication of patients. In recent years, alternative and augmentative communication technology has provided resources to restore these patients' ability to communicate.MethodsIn order to relate and classify the main methods with that purpose, this work conducted a systematic review on several journal databases.ResultsWe found 203 related papers and 55 of them were selected to compose the study. After that, we classified them into three major groups and we identified the main difficulties when using each approach.ConclusionIn order to overcome these difficulties, we propose a new system concept to develop an adaptive, robust and low cost communication environment. The proposed system is composed of five modules: data entry, communication, aid to the caregiver and external interaction.

5.
Phys Biol ; 12(1): 016008, 2015 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-25574741

RESUMO

Purpose. Circulating melanoma cells (CMCs) constitute a potentially important representation of time-resolved tumor biology in patients. To date, genomic characterization of CMCs has been limited due to the lack of a robust methodology capable of identifying them in a format suitable for downstream characterization. Here, we have developed a methodology to detect intact CMCs that enables phenotypic, morphometric and genomic analysis at the single cell level. Experimental design. Blood samples from 40 metastatic melanoma patients and 10 normal blood donors were prospectively collected. A panel of 7 chondroitin sulfate proteoglycan 4 (CSPG4)-specific monoclonal antibodies (mAbs) was used to immunocytochemically label CMCs. Detection was performed by automated digital fluorescence microscopy and multi-parametric computational analysis. Individual CMCs were captured by micromanipulation for whole genome amplification and copy number variation (CNV) analysis. Results. Based on CSPG4 expression and nuclear size, 1-250 CMCs were detected in 22 (55%) of 40 metastatic melanoma patients (0.5-371.5 CMCs ml(-1)). Morphometric analysis revealed that CMCs have a broad spectrum of morphologies and sizes but exhibit a relatively homogeneous nuclear size that was on average 1.5-fold larger than that of surrounding PBMCs. CNV analysis of single CMCs identified deletions of CDKN2A and PTEN, and amplification(s) of TERT, BRAF, KRAS and MDM2. Furthermore, novel chromosomal amplifications in chr12, 17 and 19 were also found. Conclusions. Our findings show that CSPG4 expressing CMCs can be found in the majority of advanced melanoma patients. High content analysis of this cell population may contribute to the design of effective personalized therapies in patients with melanoma.


Assuntos
Genoma Humano/genética , Melanoma/genética , Melanoma/patologia , Células Neoplásicas Circulantes/patologia , Idoso , Idoso de 80 Anos ou mais , Linhagem Celular Tumoral , Feminino , Genômica , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias
6.
Rev. bras. eng. biomed ; 28(3): 227-237, jul.-set. 2012. ilus
Artigo em Inglês | LILACS | ID: lil-659026

RESUMO

The visualization of a computerized tomographic (TC) exam in 3D increases the quality of the medical diagnosis and, consequently, the success probability in the treatment. To obtain a high quality image it is necessary to obtain slices which are close to one another. Motivated towards the goal of reaching an improved balance between quantity of slices and visualization quality, this research work presents a digital inpainting technique of 3D interpolation for CT slices used in the visualization of human body structures. The inpainting is carried out via non-linear partial differential equations (PDE). The PDE's have been used, in the image-processing context to fill in the damaged regions in a digital 2D image. Inspired by this idea, this article proposes an interpolation method for the filling in of the empty regions between the CT slices. To do it, considering the high similarity between two consecutive real slice, the first step of the proposed method is to create the virtual slices. The virtual slices contain all similarity between the intercaleted slices and, when there aren't similarities between real slices, the virtual slices will contain indefinite portions. In the second step of the proposed method, the created virtual slices will be used together with the real slices images, in the reconstruction of the structure in three dimensions, mapped onto the exam. The proposed method is capable of reconstructing the curvatures of the patient's internal structures without using slices that are close to one another. The experiments carried out show the proposed method's efficiency.


A visualização do resultado de uma tomografia computadorizada (CT) em 3D aumenta a qualidade do diagnóstico médico e, consequentemente, a probabilidade de sucesso no tratamento. Para obter uma maior qualidade na imagem 3D, é necessário obter fatias próximas umas das outras. Motivados pela meta de obter um apropriado balanceamento entre a quantidade de fatias e a qualidade da visualização, este trabalho apresenta uma técnica de retoque digital por interpolação 3D para fatias de CT usadas na visualização de estruturas do corpo humano. O retoque digital é feito através de equações diferenciais parciais não lineares (EDP). As EDPs têm sido utilizadas no contexto de processamento de imagens para preencher regiões defeituosas de imagens em 2D. Inspirado por esta ideia, este artigo propõe um método de interpolação para preencher as regiões vazias entre as fatias de TC. Para isto, considera-se a grande semelhança entre duas fatias reais consecutivas, onde o primeiro passo do método proposto é a criação de fatias virtuais. As fatias virtuais contêm todas as regiões similares entre as duas fatias intercaladas, sendo que onde não há semelhança entre as fatias reais, as fatias virtuais conterão regiões indefinidas. No segundo passo do método proposto, as fatias virtuais criadas serão utilizadas junto com as fatias reais para a reconstrução da estrutura em três dimensões, mapeadas no exame. O método é capaz de reconstruir as curvaturas das estruturas internas do paciente sem a necessidade de utilizar fatias muito próximas uma das outras. Os experimentos realizados mostram a eficiência do método proposto.

7.
Cancer Chemother Pharmacol ; 69(2): 415-24, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21800112

RESUMO

PURPOSE: Studies treating adenocarcinoma of the pancreas with gemcitabine alone or in combination with a doublet have demonstrated modest improvements in survival. Recent reports have suggested that using the triple-drug regimen FOLFIRINOX can substantially extend survival in patients with metastatic disease. We were interested in determining the clinical benefit of another three-drug regimen of gemcitabine, docetaxel and capecitabine (GTX) in patients with advanced pancreatic adenocarcinoma. PATIENTS AND METHODS: The cases of 154 patients, who received treatment with GTX chemotherapy with histologically confirmed locally advanced or metastatic pancreatic adenocarcinoma, were retrospectively reviewed. All demographic and clinical data were captured including prior therapy, adverse events, treatment response and survival. RESULTS: One hundred and seventeen metastatic and 37 locally advanced cases of adenocarcinoma of the pancreas were reviewed. Partial responses were noted in 11% of cases, and stable disease was observed in 62% of patients. Responses significantly correlated with toxicity (neutropenia, ALT elevation and hospitalizations). Grade 3 or greater hematologic and non-hematologic toxicities were noted in 41% and 9% of cases, respectively. Overall median survival was 11.6 months. Chemotherapy naïve patients with metastatic and locally advanced disease achieved a median survival of 11.3 and 25.0 months, respectively. CONCLUSIONS: We observe a substantial survival benefit with GTX chemotherapy in our cohort of patients with advanced pancreatic cancer. These findings warrant further investigation of this combination in this patient population.


Assuntos
Adenocarcinoma/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológico , Adenocarcinoma/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Alanina Transaminase/metabolismo , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Capecitabina , Desoxicitidina/administração & dosagem , Desoxicitidina/efeitos adversos , Desoxicitidina/análogos & derivados , Docetaxel , Feminino , Fluoruracila/administração & dosagem , Fluoruracila/efeitos adversos , Fluoruracila/análogos & derivados , Hospitalização/estatística & dados numéricos , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Metástase Neoplásica , Neutropenia/induzido quimicamente , Neoplasias Pancreáticas/patologia , Estudos Retrospectivos , Taxoides/administração & dosagem , Taxoides/efeitos adversos , Resultado do Tratamento , Gencitabina
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA