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1.
Opt Express ; 26(20): 25778-25792, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-30469674

RESUMO

In this work, we present a method to discriminate between different microparticle sizes in mixed flowing media based on laser feedback interferometry, which could ultimately form the basis for a small, low-cost, real-time microembolus detector. We experimentally evaluated the performance of the system using microparticle phantoms, and the system achieved approximately 45% positive predictive value and better than 98% negative predictive value in the detection and classification of abnormally large particles.

2.
Opt Lett ; 39(2): 394-7, 2014 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-24562155

RESUMO

We compare the performance of a self-mixing (SM) sensing system based on an uncooled monolithic array of 24×1 vertical-cavity surface-emitting lasers (VCSELs) in two modes of operation: single active channel and the concurrent multichannel operation. We find that the signal-to-noise ratio of individual SM sensors in a VCSEL array is markedly improved by multichannel operation, as a consequence of the increased operational temperature of the sensors. The performance improvement can be further increased by manufacturing VCSEL arrays with smaller pitch. This has the potential to produce an imaging system with high spatial and temporal resolutions that can be operated without temperature stabilization.

3.
Magn Reson Med ; 71(5): 1912-22, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-23818162

RESUMO

PURPOSE: This article aims to present a fast, efficient and accurate multi-layer integral method (MIM) for the evaluation of complex spatiotemporal eddy currents in nonmagnetic and thin volumes of irregular geometries induced by arbitrary arrangements of gradient coils. METHODS: The volume of interest is divided into a number of layers, wherein the thickness of each layer is assumed to be smaller than the skin depth and where one of the linear dimensions is much smaller than the remaining two dimensions. The diffusion equation of the current density is solved both in time-harmonic and transient domain. RESULTS: The experimentally measured magnetic fields produced by the coil and the induced eddy currents as well as the corresponding time-decay constants were in close agreement with the results produced by the MIM. Relevant parameters such as power loss and force induced by the eddy currents in a split cryostat were simulated using the MIM. CONCLUSION: The proposed method is capable of accurately simulating the current diffusion process inside thin volumes, such as the magnet cryostat. The method permits the priori-calculation of optimal pre-emphasis parameters. The MIM enables unified designs of gradient coil-magnet structures for an optimal mitigation of deleterious eddy current effects.


Assuntos
Desenho Assistido por Computador , Campos Magnéticos , Imagem por Ressonância Magnética/instrumentação , Magnetismo/instrumentação , Modelos Teóricos , Espalhamento de Radiação , Transdutores , Simulação por Computador , Desenho de Equipamento , Análise de Falha de Equipamento
4.
Med Sci Law ; 42(1): 58-63, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11848140

RESUMO

The psychiatric probation order has been a sentencing option for the courts for over fifty years. Many authors have lamented its underuse and described the inability of psychiatric and probation services to work together in a collaborative and effective way. The aim of this study was to describe probationers who had passed through Elliott House, a specialist bail and probation hostel for mentally disordered offenders. A retrospective case note review of all individuals who have been resident at Elliott House as a condition of a probation order was conducted. The individuals were mostly young, single men with a severe mental illness and comorbid substance misuse. As a group their previous contact with psychiatric services was irregular. A probation order at Elliott House appeared to provide social support and stability along with a period of regular psychiatric treatment and follow-up. The results suggest that psychiatric probation orders, if properly managed, can be a useful tool for both health and probation services in the short term.


Assuntos
Psiquiatria Legal/legislação & jurisprudência , Casas para Recuperação/estatística & dados numéricos , Cooperação do Paciente , Prisioneiros/psicologia , Adolescente , Adulto , Idoso , Comportamento Cooperativo , Psiquiatria Legal/organização & administração , Casas para Recuperação/organização & administração , Humanos , Masculino , Transtornos Mentais/classificação , Transtornos Mentais/terapia , Serviços de Saúde Mental/organização & administração , Serviços de Saúde Mental/estatística & dados numéricos , Pessoa de Meia-Idade , Prisioneiros/legislação & jurisprudência , Estudos Retrospectivos , Apoio Social , Reino Unido
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