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1.
Rev Sci Instrum ; 95(4)2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38647367

RESUMEN

This paper demonstrates an optical technique to measure magnetostrictive strain in a cryogenic environment using a Fabry-Pérot resonator spaced by crystal samples. Optical measurement techniques are calibration-free and highly sensitive. This technique was used to measure the magnetostrictive strain of neodymium gallate at a temperature of 49 mK to be λ = 1.3 × 10-5 at 3 T, with a sensitivity of 3.0 × 10-8. We highlight the interesting properties of the crystal's magnetic ordering. The sensitivity of this technique was limited by the wavemeter used to measure the laser frequency, and significant improvements in the sensitivity should be possible.

3.
Light Sci Appl ; 10(1): 228, 2021 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-34750343
4.
Light Sci Appl ; 10(1): 214, 2021 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-34650033

RESUMEN

The intra-cavity electro-magnetic field distribution in a microdisk resonator can be visualised by inducing a phase shift via a scanning probe beam.

5.
Opt Lett ; 46(10): 2477-2480, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33988614

RESUMEN

Small perturbations in the dielectric environment around resonant dielectric structures usually lead to a frequency shift of the resonator modes directly proportional to the polarizability of the perturbation. Here, we report experimental observations of strong frequency shifts that can oppose and even exceed the contribution of the perturbations' polarizability. We show in particular how the mode frequencies of a lithium niobate whispering-gallery-mode resonator are shifted by planar substrates-of refractive indices ranging from 1.50 to 4.22-contacting the resonator rim. Both blue- and redshifts are observed, as well as an increase in mode linewidth, when substrates are moved into the evanescent field of the whispering gallery mode. We compare the experimental results to a theoretical model by Foreman et al. [J. Opt. Soc. Am. B33, 2177 (2016)JOBPDE0740-322410.1364/JOSAB.33.002177] and provide an additional intuitive explanation based on the Goos-Hänchen shift for the optical domain, with applications to dielectric structures ranging from meta-surfaces to photonic crystal cavities.

6.
Pediatr Surg Int ; 37(1): 109-117, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33159555

RESUMEN

PURPOSE: To explore the factors involved in the demise of tunnelled central vascular access devices (CVADs) in children and describe patterns of failure. METHODS: A retrospective study including children under 16 years of age undergoing CVAD insertion in a tertiary centre between October 2014 and December 2019. The Kaplan-Meier estimator was used to study CVAD survival and piecewise exponential curves to approximate hazard rates. Related factors were analysed using multivariable regression. RESULTS: Totally, 684 CVADs were inserted in 499 children. Devices were in situ for 213,821 days (median 244.5). Of those, 261 CVADs (38.2%) failed prematurely; 176 (67%) required replacement. Tunnelled external lines (TELs) failed more frequently than totally implantable devices (p < 0.005).TEL displacement occurred in two high-risk phases, falling to baseline after 90 days. Low age at device insertion and open placement were strongly associated with an increased failure rate. Previous CVAD failure did not increase subsequent failure rate. Premature failure increased procedural cost by £153,949 per year. CONCLUSIONS: TIDs should be placed in preference to TELs where appropriate. TELs are at highest risk of displacement for 90 days and must be well secured for this duration. Meticulous line care offers significant potential cost savings by reducing line replacements. LEVEL OF EVIDENCE: Level III.


Asunto(s)
Cateterismo Venoso Central/instrumentación , Catéteres de Permanencia/efectos adversos , Catéteres Venosos Centrales/efectos adversos , Falla de Equipo/estadística & datos numéricos , Niño , Preescolar , Femenino , Humanos , Masculino , Estudios Retrospectivos , Análisis de Supervivencia , Reino Unido
7.
J Clin Med ; 9(8)2020 Aug 08.
Artículo en Inglés | MEDLINE | ID: mdl-32784470

RESUMEN

Work from our laboratory documents pathological events, including myofiber oxidative damage and degeneration, myofibrosis, micro-vessel (diameter = 50-150 µm) remodeling, and collagenous investment of terminal micro-vessels (diameter ≤ 15 µm) in the calf muscle of patients with Peripheral Artery Disease (PAD). In this study, we evaluate the hypothesis that the vascular pathology associated with the legs of PAD patients encompasses pathologic changes to the smallest micro-vessels in calf muscle. Biopsies were collected from the calf muscle of control subjects and patients with Fontaine Stage II and Stage IV PAD. Slide specimens were evaluated by Quantitative Multi-Spectral and Fluorescence Microscopy. Inter-myofiber collagen, stained with Masson Trichrome (MT), was increased in Stage II patients, and more substantially in Stage IV patients in association with collagenous thickening of terminal micro-vessel walls. Evaluation of the Basement Membrane (BM) of these vessels reveals increased thickness in Stage II patients, and increased thickness, diameter, and Collagen I deposition in Stage IV patients. Coverage of these micro-vessels with pericytes, key contributors to fibrosis and BM remodeling, was increased in Stage II patients, and was greatest in Stage IV patients. Vascular pathology of the legs of PAD patients extends beyond atherosclerotic main inflow arteries and affects the entire vascular tree-including the smallest micro-vessels.

8.
J Water Health ; 16(1): 93-101, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29424723

RESUMEN

Iron is one of the most common elements in the Earth's crust, which corresponds to it being a common constituent in drinking water supplies. Residents of Bithlo, an unincorporated community in east-central Florida, have observed that their drinking water tastes like metal and stains clothing and teeth. An evaluation of water samples collected from over 200 private drinking water wells revealed iron concentrations that exceeded the US Environmental Protection Agency's (EPA's) secondary standard of 0.3 mg/L. Households with and without point-of-entry treatment were found to have over three times (0.92 mg/L) and ten times (3.86 mg/L) more iron than the EPA's secondary standard, respectively. The human health-based threshold of 4.2 mg/L established by the Centers for Disease Control and Prevention was exceeded in 38.6% of untreated residences. Community-wide statistical and spatial water-quality trends were developed by combining the collected well water quality data with historically available water quality reports. Spatial analyses revealed that greater than 99% of the Bithlo community's private household supplies would exceed the EPA's drinking water secondary standard.


Asunto(s)
Agua Potable/química , Monitoreo del Ambiente/métodos , Hierro/análisis , Contaminantes Químicos del Agua/análisis , Pozos de Agua , Florida , Geografía Médica , Humanos , Calidad del Agua
9.
Dev Growth Differ ; 57(8): 570-80, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26464005

RESUMEN

The zinc-finger transcription factor GLI3 acts as a primary transducer of Sonic hedgehog (Shh) signaling in a context-dependent combinatorial fashion. GLI3 participates in the patterning and growth of many organs, including the central nervous system (CNS) and limbs. Previously, we reported a subset of human intronic cis-regulators controlling many known aspects of endogenous Gli3 expression in mouse and zebrafish. Here we demonstrate in a transgenic zebrafish assay the potential of two novel tetrapod-teleost conserved non-coding elements (CNEs) docking within GLI3 intronic intervals (intron 3 and 4) to induce reporter gene expression at known sites of endogenous Gli3 transcription in embryonic domains such as the central nervous system (CNS) and limbs. Interestingly, the cell culture based assays reveal harmony with the context dependent dual nature of intra-GLI3 conserved elements. Furthermore, a transgenic zebrafish assay of previously reported limb-specific GLI3 transcriptional enhancers (previously tested in mice and chicken limb buds) induced reporter gene expression in zebrafish blood precursor cells and notochord instead of fin. These results demonstrate that the appendage-specific activity of a subset of GLI3-associated enhancers might be a tetrapod innovation. Taken together with our recent data, these results suggest that during the course of vertebrate evolution Gli3 expression control acquired a complex cis-regulatory landscape for spatiotemporal patterning of CNS and limbs. Comparative data from fish and mice suggest that the functional aspects of a subset of these cis-regulators have diverged significantly between these two lineages.


Asunto(s)
Regulación del Desarrollo de la Expresión Génica , Factores de Transcripción de Tipo Kruppel/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Factores de Transcripción/metabolismo , Pez Cebra/metabolismo , Animales , Animales Modificados Genéticamente/genética , Animales Modificados Genéticamente/metabolismo , Elementos de Facilitación Genéticos/genética , Elementos de Facilitación Genéticos/fisiología , Humanos , Factores de Transcripción de Tipo Kruppel/genética , Ratones , Proteínas del Tejido Nervioso/genética , Factores de Transcripción/genética , Pez Cebra/genética , Proteína Gli3 con Dedos de Zinc
10.
MAGMA ; 28(1): 33-48, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24802620

RESUMEN

OBJECT: A new method for 3D localization of N fiducial markers from 1D projections is presented and analysed. It applies to semi-active markers and active markers using a single receiver channel. MATERIALS AND METHODS: The novel algorithm computes candidate points using peaks in three optimally selected projections and removes fictitious points by verifying detected peaks in additional projections. Computational complexity was significantly reduced by avoiding cluster analysis, while higher accuracy was achieved by using optimal projections and by applying Gaussian interpolation in peak detection. Computational time, accuracy and robustness were analysed through Monte Carlo simulations and experiments. The method was employed in a prototype MRI guided prostate biopsy system and used in preclinical experiments. RESULTS: The computational time for 6 markers was better than 2 ms, an improvement of up to 100 times, compared to the method by Flask et al. (J Magn Reson Imaging 14(5):617-627, 2001). Experimental maximum localization error was lower than 0.3 mm; standard deviation was 0.06 mm. Targeting error was about 1 mm. Tracking update rate was about 10 Hz. CONCLUSION: The proposed method is particularly suitable in systems requiring any of the following: high frame rate, tracking of three or more markers, data filtering or interleaving.


Asunto(s)
Algoritmos , Marcadores Fiduciales , Interpretación de Imagen Asistida por Computador/métodos , Imagenología Tridimensional/métodos , Imagen por Resonancia Magnética Intervencional/instrumentación , Imagen por Resonancia Magnética Intervencional/métodos , Humanos , Aumento de la Imagen/métodos , Reconocimiento de Normas Patrones Automatizadas/métodos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
11.
Nano Lett ; 14(3): 1148-52, 2014 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-24512422

RESUMEN

A metallic double dot is measured with radio frequency reflectometry. Changes in the total electron number of the double dot are determined via single electron tunnelling contributions to the complex electrical impedance. Electron counting experiments are performed by monitoring the impedance, demonstrating operation of a single electron ammeter without the need for external charge detection.

12.
AANA J ; 77(2): 110-4, 2009 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19388505

RESUMEN

We conducted a randomized clinical trial of patients undergoing laparoscopic gynecologic surgery to determine the effect of a calculated preoperative fluid bolus on postoperative nausea and vomiting (PONV). For the study, 46 women were randomly assigned to an experimental group, group 1, or a control group, group 2. Group 1 received up to 1,000 mL of replacement fluid preoperatively, using the 4-2-1 formula. Group 2 received the anesthesia provider's routine replacement fluids. Neither group received antiemetics preoperatively or intraoperatively. All patients were assessed for PONV by nurses blinded to patient group assignment. Group 1 patients experienced significantly lower occurrences of PONV than did group 2 patients (P = .046). The preoperative fluid bolus seemed to be a significant factor in preventing PONV in group 1. Demographic and other factors reported to cause PONV, such as the length of surgery and major manipulation of the bowels, were similar in both groups. There was no significant difference between groups in reception of postoperative opioid, a known cause of PONV. Drops in blood pressure were thought to affect PONV, but group 1 patients had larger decreases in blood pressure than did group 2 patients.


Asunto(s)
Fluidoterapia/métodos , Procedimientos Quirúrgicos Ginecológicos/efectos adversos , Náusea y Vómito Posoperatorios/prevención & control , Cuidados Preoperatorios , Adolescente , Adulto , Anciano , Método Doble Ciego , Femenino , Humanos , Laparoscopía , Persona de Mediana Edad , Estudios Prospectivos
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