Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
1.
Sensors (Basel) ; 18(11)2018 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-30400377

RESUMO

Continuous authentication systems for mobile devices focus on identifying users according to their behaviour patterns when they interact with mobile devices. Among the benefits provided by these systems, we highlight the enhancement of the system security, having permanently authenticated the users; and the improvement of the users' quality of experience, minimising the use of authentication credentials. Despite the benefits of these systems, they also have open challenges such as the authentication accuracy and the adaptability to new users' behaviours. Continuous authentication systems should manage these challenges without forgetting critical aspects of mobile devices such as battery consumption, computational limitations and response time. With the goal of improving these previous challenges, the main contribution of this paper is the design and implementation of an intelligent and adaptive continuous authentication system for mobile devices. The proposed system enables the real-time users' authentication by considering statistical information from applications, sensors and Machine Learning techniques based on anomaly detection. Several experiments demonstrated the accuracy, adaptability, and resources consumption of our solution. Finally, its utility is validated through the design and implementation of an online bank application as proof of concept, which allows users to perform different actions according to their authentication level.


Assuntos
Algoritmos , Telefone Celular , Segurança Computacional , Área Sob a Curva , Fontes de Energia Elétrica , Humanos , Máquina de Vetores de Suporte , Fatores de Tempo
2.
Ann Surg Oncol ; 19(7): 2367-79, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22395973

RESUMO

BACKGROUND: Glioblastoma multiforme (GBM) is the most common primary tumor of the central nervous system in adults. Patients with GBM have few treatment options, and their disease is invariably fatal. Molecularly targeted agents offer the potential to improve patient treatment; however, the use of these will require a fuller understanding of the genetic changes in this complex tumor. METHODS: We analyzed a series of 32 patients with GBM with array comparative genomic hybridization in combination with gene expression analysis. We focused on the recurrent breakpoints found by spectral karyotyping (SKY). RESULTS: By SKY we identified 23 recurrent breakpoints of the 202 translocations found in GBM cases. Gains and losses were identified in chromosomal regions close to the breakpoints by array comparative genomic hybridization. We evaluated the genes located in the regions involved in the breakpoints in depth. A list of 406 genes that showed a level of expression significantly different between patients and control subjects was selected to determine their effect on survival. Genes CACNA2D3, PPP2R2B, SIK, MAST3, PROM1, and PPP6C were significantly associated with shorter survival (median 200 days vs. 450 days, P≤0.03). CONCLUSIONS: We present a list of genes located in regions of breakpoints that could be grounds for future studies to determine whether they are crucial in the pathogenesis of this type of tumor, and we provide a list of six genes associated with the clinical outcome of patients with GBM.


Assuntos
Biomarcadores Tumorais/genética , Aberrações Cromossômicas , Hibridização Genômica Comparativa , Perfilação da Expressão Gênica , Glioblastoma/genética , Glioblastoma/patologia , Cariotipagem Espectral , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Glioblastoma/mortalidade , Humanos , Cariotipagem , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Análise de Sequência com Séries de Oligonucleotídeos , Prognóstico , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Risco , Taxa de Sobrevida
3.
PLoS One ; 8(9): e76401, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24073290

RESUMO

Malignant astrocytomas are the most aggressive primary brain tumors with a poor prognosis despite optimal treatment. Dysfunction of mismatch repair (MMR) system accelerates the accumulation of mutations throughout the genome causing uncontrolled cell growth. The aim of this study was to characterize the MMR system defects that could be involved in malignant astrocytoma pathogenesis. We analyzed protein expression and promoter methylation of MLH1, MSH2 and MSH6 as well as microsatellite instability (MSI) and MMR gene mutations in a set of 96 low- and high-grade astrocytomas. Forty-one astrocytomas failed to express at least one MMR protein. Loss of MSH2 expression was more frequent in low-grade astrocytomas. Loss of MLH1 expression was associated with MLH1 promoter hypermethylation and MLH1-93G>A promoter polymorphism. However, MSI was not related with MMR protein expression and only 5% of tumors were MSI-High. Furthermore, the incidence of tumors carrying germline mutations in MMR genes was low and only one glioblastoma was associated with Lynch syndrome. Interestingly, survival analysis identified that tumors lacking MSH6 expression presented longer overall survival in high-grade astrocytoma patients treated only with radiotherapy while MSH6 expression did not modify the prognosis of those patients treated with both radiotherapy and chemotherapy. Our findings suggest that MMR system alterations are a frequent event in malignant astrocytomas and might help to define a subgroup of patients with different outcome.


Assuntos
Astrocitoma/genética , Biomarcadores Tumorais/análise , Metilação de DNA , Reparo de Erro de Pareamento de DNA/genética , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Mutação/genética , Adulto , Idoso , Astrocitoma/metabolismo , Astrocitoma/mortalidade , Astrocitoma/patologia , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Estudos de Coortes , Feminino , Humanos , Técnicas Imunoenzimáticas , Masculino , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Gradação de Tumores , Prognóstico , Regiões Promotoras Genéticas/genética , Taxa de Sobrevida , Análise Serial de Tecidos
4.
Virchows Arch ; 456(6): 681-7, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20422214

RESUMO

Elastofibroma is a rare, benign fibrous proliferation that most commonly occur in periscapular soft tissues and is characterized by accumulated elastic fibers. Although the lesion is generally regarded as a reactive process, an unusual fibroblastic pseudotumor or as a fibroelastic tumor-like lesion, its etiology remains unknown. Cytogenetic studies in these lesions detected chromosomal instability and some recurrent clonal chromosomal changes, which raised the possibility that the lesion represents a neoplastic process. Here, we report the genomic alterations detected by array-based comparative genomic hybridization (aCGH) and by multiplex ligation-dependent probe amplification (MLPA) in two cases of elastofibroma. Both cases showed losses on 1p, 13q, 19p, and 22q by aCGH. In addition, deletion of CASR (3q21), GSTP1 (11q13), BRCA2 (13q12) and gains on APC (5q21) and PAH (12q23) were observed by MLPA in both samples. Genomic screening studies of this fibrous proliferation may lead to identify chromosomal regions containing genes involved in the development of elastofibromas.


Assuntos
Aberrações Cromossômicas , Hibridização Genômica Comparativa , Fibroma/genética , Técnicas de Amplificação de Ácido Nucleico , Neoplasias de Tecidos Moles/genética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA