Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 28
Filtrar
1.
Microsyst Nanoeng ; 8: 129, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36533261

RESUMO

Atomic devices such as atomic clocks and optically-pumped magnetometers rely on the interrogation of atoms contained in a cell whose inner content has to meet high standards of purity and accuracy. Glass-blowing techniques and craftsmanship have evolved over many decades to achieve such standards in macroscopic vapor cells. With the emergence of chip-scale atomic devices, the need for miniaturization and mass fabrication has led to the adoption of microfabrication techniques to make millimeter-scale vapor cells. However, many shortcomings remain and no process has been able to match the quality and versatility of glass-blown cells. Here, we introduce a novel approach to structure, fill and seal microfabricated vapor cells inspired from the century-old approach of glass-blowing, through opening and closing single-use zero-leak microfabricated valves. These valves are actuated exclusively by laser, and operate in the same way as the "make-seals" and "break-seals" found in the filling apparatus of traditional cells. Such structures are employed to fill cesium vapor cells at the wafer-level. The make-seal structure consists of a glass membrane that can be locally heated and deflected to seal a microchannel. The break-seal is obtained by breaching a silicon wall between cavities. This new approach allows adapting processes previously restricted to glass-blown cells. It can also be extended to vacuum microelectronics and vacuum-packaging of micro-electro-mechanical systems (MEMS) devices.

2.
Opt Express ; 30(3): 3749-3759, 2022 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-35209627

RESUMO

We report on the fabrication of micro-axicons made of glass by laser-assisted wet etching (LAE) and laser polishing. The employed technique, relying on a direct-writing process using a femtosecond laser, allows revealing high fidelity profiles when the exposed glass samples are etched in a heated potassium hydroxide (KOH) solution. The remaining surface roughness is then decreased by carbon dioxide (CO2) laser polishing. Such polishing is limited to the superficial layer of the component so that the tip is only slightly rounded, with a radius of curvature of nearly 200 µm. It is then shown with 500 µm-diameter axicons that a quasi-Bessel beam is generated closely after the tip and features a 5.3 µm diameter maintained over a propagation distance of almost 3.5 mm.

3.
CJC Open ; 3(11): 1341-1346, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34901802

RESUMO

BACKGROUND: The CardioSTAT is a single-lead ambulatory electrocardiography monitor that has been validated for use in adult patients. Recording is made through 2 electrodes positioned in a lead-I configuration, and the device allows monitoring for 2, 7, or 14 days. We sought to investigate the efficacy of this device in children with paroxysmal palpitations. METHODS: In phase I, the quality of tracings from simultaneous CardioSTAT recordings and D1-lead recordings of a standard 12-lead electrocardiography machine in 23 children were compared. Phase II was a prospective observational cohort study comparing arrhythmia detection using the CardioSTAT vs currently used devices (24-hour Holter monitor and the Cardiomemo loop recorder) in 52 children complaining of palpitations. RESULTS: In Phase I, all but 3 rhythm strips were correctly identified. The pacing spikes on 3 strips were not adequately identified by the observers for the CardioSTAT recording. In Phase II, symptomatic episodes were reported in 42%, 73%, and 100% of subjects during monitoring with the Holter, Cardiomemo, and CardioSTATdevices, respectively. An abnormal rhythm was detected in 13%, 23%, and 35% of subjects by the Holter, Cardiomemo, and CardioSTAT monitors, respectively. The underlying rhythm during symptomatic events was determined in 90% of cases with the CardioSTAT monitor, whereas it was determined in only 19% and 29% of cases using the Holter and Cardiomemo monitors, respectively. CONCLUSIONS: The CardioSTAT monitor provided good-quality tracings and was superior to the 24-hour Holter monitor and the Cardiomemo loop recorder in determining the presence or absence of pathologic arrhythmia in the study cohort.


CONTEXTE: Le CardioSTAT est un moniteur d'électrocardiographie ambulatoire à dérivation unique dont l'utilisation a été validée chez les patients adultes. L'enregistrement se fait au moyen de 2 électrodes positionnées dans une configuration de type « dérivation I ¼, et l'appareil permet un suivi pendant 2, 7 ou 14 jours. Nous avons cherché à étudier l'efficacité de cet appareil chez les enfants atteints de palpitations paroxystiques. MÉTHODOLOGIE: Dans la phase I, la qualité des tracés provenant d'enregistrements simultanés de CardioSTAT et d'enregistrements de la dérivation I d'un appareil d'électrocardiographie standard à 12 dérivations a été comparée chez 23 enfants. La phase II était une étude de cohorte observationnelle prospective comparant la détection de l'arythmie à l'aide du moniteur CardioSTAT par rapport aux appareils utilisés actuellement (moniteur Holter à surveillance sur 24 heures et enregistreur d'événements portatif Cardiomémo) chez 52 enfants se plaignant de palpitations. RÉSULTATS: Dans la phase I, toutes les bandes d'enregistrement sauf trois ont été correctement identifiées. Les spicules de stimulation n'ont pas été correctement détectés par les observateurs sur trois bandes d'enregistrement du moniteur CardioSTAT. Dans la phase II, des épisodes symptomatiques ont été signalés chez 42 %, 73 % et 100 % des sujets pendant la surveillance avec les appareils Holter, Cardiomémo et CardioSTAT, respectivement. Un rythme anormal a été détecté chez 13 %, 23 % et 35 % des sujets par les moniteurs Holter, Cardiomémo et CardioSTAT, respectivement. Le rythme sous-jacent pendant les événements symptomatiques a été déterminé dans 90 % des cas avec le moniteur CardioSTAT, alors qu'il n'a été déterminé que dans 19 % et 29 % des cas, respectivement, avec les moniteurs Holter et Cardiomémo. CONCLUSIONS: Le moniteur CardioSTAT a fourni des tracés de bonne qualité et s'est révélé supérieur à l'appareil Holter à surveillance sur 24 heures et à l'enregistreur d'événements portatif Cardiomémo pour déterminer la présence ou l'absence d'arythmie pathologique dans la cohorte étudiée.

4.
J Card Surg ; 36(2): 701-702, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33259089

RESUMO

Invasive endocarditis involving the fibrous skeleton of the heart requires complex high-risk surgical management. For combined aortic and mitral infection in whom the posterior mitral leaflet and at least the free edge of anterior mitral valve could be spared, a modification of the Commando procedure was suggested: the "Hemi-commando procedure." We report the autopsy images of a Hemi-commando procedure after in unfortunate death in a 24 years old man 17 days after surgery.


Assuntos
Endocardite , Implante de Prótese de Valva Cardíaca , Adulto , Valva Aórtica/diagnóstico por imagem , Valva Aórtica/cirurgia , Autopsia , Endocardite/cirurgia , Humanos , Masculino , Valva Mitral/diagnóstico por imagem , Valva Mitral/cirurgia , Adulto Jovem
5.
Pediatr Cardiol ; 41(8): 1645-1650, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32851436

RESUMO

Bicuspid aortic valve (BAV) is the most common congenital heart disease. Since heritability is suspected, actual guidelines recommend to perform an echocardiographic assessment for first-degree relatives (FDR) of patient with BAV. This study aimed to assess the effectiveness and the feasibility of the current guidelines for the screening of FDR of patient with BAV in a pediatric cardiology daily practice. Consecutive patients with BAV and their FDR were prospectively included from January 2015 to March 2018 at Centre Hospitalier Universitaire de Laval, Quebec City (Canada). Data were retrospectively collected and analyzed. A total of 713 FDR of 213 consecutives index cases [median age: 11 (6-20) years] were studied. Up to 32 (6.6%) FDR had a BAV and 26 (5.4%) had an aortic valve dysfunction. A total of 14 (2.9%) FDR had an ascending aorta dilatation according to Z-score including 6 (1.2%) patients with an ascending aorta ≥ 45 mm. No statistically significant differences regarding BAV, aortic valve dysfunction and ascending aorta dilatation prevalence were identified between generations. Screening was done in 482 (67.6%), prescribed but not done in 134 (19%), not prescribed in 92 (13%) and declined in 5 (1%) FDR. The prevalence of BAV in FDR was similar to prospective adult studies and supports actual guidelines in pediatric cardiology practice. Ascending aorta dilatation was rare in our young population. Exhaustiveness and additional burden to implement current guidelines remain a challenge in daily practice.


Assuntos
Doença da Válvula Aórtica Bicúspide/diagnóstico , Programas de Rastreamento/métodos , Pediatria/normas , Guias de Prática Clínica como Assunto , Adolescente , Aorta/diagnóstico por imagem , Aorta/patologia , Doenças da Aorta/diagnóstico , Doenças da Aorta/epidemiologia , Valva Aórtica/diagnóstico por imagem , Valva Aórtica/patologia , Doença da Válvula Aórtica Bicúspide/epidemiologia , Canadá , Cardiologia/normas , Criança , Ecocardiografia , Família , Estudos de Viabilidade , Feminino , Humanos , Masculino , Prevalência , Estudos Retrospectivos , Adulto Jovem
6.
Opt Express ; 28(6): 8512-8527, 2020 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-32225475

RESUMO

Laser scanning based on Micro-Electro-Mechanical Systems (MEMS) scanners has become very attractive for biomedical endoscopic imaging, such as confocal microscopy or Optical Coherence Tomography (OCT). These scanners are required to be fast to achieve real-time image reconstruction while working at low actuation voltage to comply with medical standards. In this context, we report a 2-axis Micro-Electro-Mechanical Systems (MEMS) electrothermal micro-scannercapable of imaging large fields of view at high frame rates, e.g. from 10 to 80 frames per second. For this purpose, Lissajous scan parameters are chosen to provide the optimal image quality within the scanner capabilities and the sampling rate limit, resulting from the limited A-scan rate of typical swept-sources used for OCT. Images of 233 px × 203 px and 53 px × 53 px at 10 fps and 61 fps, respectively, are experimentally obtained and demonstrate the potential of this micro-scannerfor high definition and high frame rate endoscopic Lissajous imaging.


Assuntos
Sistemas Microeletromecânicos/métodos , Imagem Óptica/métodos , Sistemas Computacionais , Endoscópios , Endoscopia/métodos , Desenho de Equipamento , Humanos , Processamento de Imagem Assistida por Computador , Sistemas Microeletromecânicos/instrumentação , Sistemas Microeletromecânicos/estatística & dados numéricos , Microscopia Confocal/instrumentação , Microscopia Confocal/métodos , Microscopia Confocal/estatística & dados numéricos , Dispositivos Ópticos , Imagem Óptica/instrumentação , Imagem Óptica/estatística & dados numéricos , Fenômenos Ópticos , Tomografia de Coerência Óptica/instrumentação , Tomografia de Coerência Óptica/métodos , Tomografia de Coerência Óptica/estatística & dados numéricos
7.
Pediatr Blood Cancer ; 67(6): e28197, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32207557

RESUMO

Fibrin sheath formation around long-term indwelling central venous catheters is common and usually benign. Fibrin sheath can persist after catheter removal and rarely leads to complications. This is a report of three pediatric oncology patients that required cardiac surgery for cardiac embolization of a "ghost" catheter several years after catheter removal. One case required tricuspid valve replacement for complete tricuspid valve destruction and two had erosion through the atrial wall. The severity of these rare complications mandates follow-up of "ghost" catheters in pediatric oncology patients.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Procedimentos Cirúrgicos Cardíacos/métodos , Cateteres de Demora/efeitos adversos , Embolia/cirurgia , Átrios do Coração/cirurgia , Linfoma não Hodgkin/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Adolescente , Criança , Embolia/etiologia , Embolia/patologia , Átrios do Coração/patologia , Humanos , Linfoma não Hodgkin/patologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Prognóstico
9.
Ann Thorac Surg ; 110(2): 638-644, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-31881194

RESUMO

BACKGROUND: Aortic valve replacement in children represents an important challenge. Concerns regarding pulmonary autograft and homograft longevity requiring reoperations are well recognized. Very long-term outcomes after the Ross procedure are still unknown. We reviewed our experience with the Ross procedure, aiming to define very long-term survival rate and freedom from reintervention. METHODS: This was a single-center retrospective cohort including 63 consecutive children who underwent the Ross procedure. Median follow-up duration was 20.5 years. Time-related events were assessed using Kaplan-Meier estimator. RESULTS: There were 51 (81%) boys, mean age 10.1 ± 5.8 years. Isolated aortic stenosis was the most common diagnosis (n = 29, 46%) and 34 (54%) patients previously underwent cardiac surgery. There was 1 (1.6%) in-hospital death. Overall survival at 5, 15, and 25 years was 96.7%, 94.4%, and 94.4%, respectively. Freedom from any autograft-related reintervention was 98.1%, 86.4%, and 61.2% at 5, 15, and 25 years, respectively. Fifteen (24%) patients underwent autograft reoperations. Among them, 10 (67%) patients underwent valve-sparing autograft reoperation. Freedom from any pulmonary conduit reintervention was 93.2%, 58.2%, and 28.3% at 5, 15, and 25 years, respectively. Thirty (46.6%) patients underwent conduit reintervention (8 percutaneous, 22 surgical replacements). CONCLUSIONS: The pediatric Ross procedure is associated with excellent long-term survival. Ross-related reinterventions are more than twice as common on the pulmonary homograft than on the autograft.


Assuntos
Estenose da Valva Aórtica/cirurgia , Bioprótese , Previsões , Implante de Prótese de Valva Cardíaca/métodos , Estenose da Valva Aórtica/mortalidade , Autoenxertos , Criança , Feminino , Seguimentos , Humanos , Masculino , Quebeque/epidemiologia , Estudos Retrospectivos , Taxa de Sobrevida/tendências , Resultado do Tratamento
10.
Rev Esp Cardiol (Engl Ed) ; 73(3): 219-224, 2020 Mar.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-31585849

RESUMO

INTRODUCTION AND OBJECTIVES: Randomized trials have shown the efficacy of transcatheter closure of patent foramen ovale (PFO) in patients aged ≤ 60 years with cryptogenic embolism. We aimed to assess the long-term safety and efficacy of PFO closure in patients aged> 60 years. METHODS: Of 475 consecutive patients with cryptogenic embolism who underwent PFO closure, 90 older patients aged> 60 years (mean, 66±5 years) were compared with 385 younger patients aged ≤ 60 years (mean, 44±10 years). RESULTS: Older patients had a higher prevalence of cardiovascular risk factors (CVRF) (hypertension, dyslipidemia, diabetes; P <.01 for all vs younger patients). There were no differences in periprocedural complications between the 2 groups. During a median follow-up of 8 (4-12) years, there were a total of 17 deaths, all from noncardiovascular causes (7.8% and 2.6% in the older and younger patient groups, respectively; HR, 4.12; 95%CI, 1.56-10.89). Four patients had a recurrent stroke (2.2% and 0.5% in the older and younger patient groups, respectively; HR, 5.08; 95%CI, 0.71-36.2), and 12 patients had a transient ischemic attack (TIA) (3.3% and 2.3% in the older and younger patient groups, respectively; HR, 1.71; 95%CI, 0.46-6.39). There was a trend toward a higher rate of the composite of stroke/TIA in older patients (5.5% vs 2.6%; HR, 2.62; 95%CI, 0.89-7.75; P=.081), which did not persist after adjustment for CVRF (HR, 1.97; 95%CI, 0.59-6.56; P=.269). CONCLUSIONS: In older patients with cryptogenic embolism, PFO closure was safe and associated with a low rate of ischemic events at long-term. However, older patients exhibited a tendency toward a higher incidence of recurrent stroke/TIA compared with younger patients, likely related to a higher burden of CVRF.


Assuntos
Embolia/complicações , Forame Oval Patente/cirurgia , Ataque Isquêmico Transitório/epidemiologia , Dispositivo para Oclusão Septal , Acidente Vascular Cerebral/epidemiologia , Adulto , Fatores Etários , Idoso , Causas de Morte , Diabetes Mellitus/epidemiologia , Dislipidemias/epidemiologia , Feminino , Forame Oval Patente/complicações , Forame Oval Patente/mortalidade , Humanos , Hipertensão/epidemiologia , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/epidemiologia , Prevalência , Recidiva , Fatores de Risco
11.
Nat Commun ; 10(1): 4583, 2019 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-31594937

RESUMO

Manipulation of mechanical motion at the micro-scale has been attracting continuous attention, leading to the successful implementation of various strategies with potential impact on classical and quantum information processing. We propose an approach based on the interplay between a pair of localised mechanical resonators and travelling surface acoustic waves (SAW). We demonstrate the existence of a two-sided interaction, allowing the use of SAW to trigger and control the resonator oscillation, and to manipulate the elastic energy distribution on the substrate through resonator coupling. Observation of the vectorial structure of the resonator motion reveals the existence of two coupling regimes, a dipole-dipole-like interaction at small separation distance versus a surface-mediated mechanical coupling at larger separation. These results illustrate the potential of this platform for coherent control of mechanical vibration at a resonator level, and reciprocally for manipulating SAW propagation using sub-wavelength elements.

12.
Can J Cardiol ; 35(4): 544.e3-544.e5, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30935649

RESUMO

Cardiac hemangioma is rare, even more when leading to a cardiovascular collapse in a seemingly healthy newborn. A 6-day-old neonate had a tamponade caused by a basolateral hemangioma of the left ventricle. Partial surgical resection was performed. A congenital lobular capillary hemangioma was diagnosed upon histologic examination. The patient recovered completely and shows normal development at the 12-month follow-up.


Assuntos
Tamponamento Cardíaco/etiologia , Parada Cardíaca/etiologia , Neoplasias Cardíacas/complicações , Hemangioma Capilar/complicações , Tamponamento Cardíaco/complicações , Neoplasias Cardíacas/cirurgia , Hemangioma Capilar/cirurgia , Humanos , Recém-Nascido , Masculino
13.
Am J Cardiol ; 123(9): 1538-1545, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30792001

RESUMO

No data exist on the optimal duration of antithrombotic therapy (AT) following patent foramen ovale (PFO) closure. We sought to assess the safety of AT discontinuation following PFO closure in patients with a cryptogenic ischemic event. A total of 453 consecutive patients (mean age: 48 ± 13years, men: 51%) who underwent PFO closure due to a cryptogenic ischemic event were included. All patients were on AT following PFO closure (antiplatelet therapy: 92.7%, anticoagulation: 7.3%). Ischemic and bleeding events, and AT were assessed at a median follow-up of 8 (IQR: 4 to 11) years, and follow-up was complete in 96% of patients. Stroke and transient ischemic attack occurred in 4 (0.9%) and 12 (2.6%) patients, respectively, and 27 (6.0%) patients had bleeding events (major in 6 [1.3%] patients, including 4 episodes of intracranial hemorrhage). All major bleeding events occurred under aspirin therapy. A total of 82 patients (18%) stopped the AT at a median of 7 (IQR: 5 to 34) months post-PFO closure (due to a bleeding event or gastrointestinal symptoms: 13 patients, no specific reason: 69 patients), and none of them had any ischemic event after a median time of 7 (IQR 3 to 10) years without any AT. A propensity score matched analysis including 46 patients who discontinued the AT within 1-year post-PFO closure and 120 patients with an ongoing AT showed the lack of differences in ischemic events between groups (0 vs 0.2 stroke/transient ischemic attack per 100 patient-years in the no-AT and AT groups, respectively). In conclusion, in young patients who underwent PFO closure, bleeding events occurred in ∼6% of patients after a median follow-up of 8years. AT was discontinued in about one fifth of patients (most of them within the year following PFO closure), and this was not associated with any increase in ischemic events at long-term follow-up. These results suggest that, in patients without other co-morbidities increasing the risk of stroke, temporary AT following PFO closure may be a reasonable strategy.


Assuntos
Isquemia Encefálica/prevenção & controle , Procedimentos Cirúrgicos Cardíacos/métodos , Fibrinolíticos/uso terapêutico , Forame Oval Patente/cirurgia , Complicações Pós-Operatórias/prevenção & controle , Prevenção Secundária/métodos , Suspensão de Tratamento , Isquemia Encefálica/epidemiologia , Isquemia Encefálica/etiologia , Feminino , Seguimentos , Forame Oval Patente/complicações , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Prognóstico , Quebeque/epidemiologia , Estudos Retrospectivos , Dispositivo para Oclusão Septal , Taxa de Sobrevida/tendências
14.
J Am Coll Cardiol ; 73(3): 278-287, 2019 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-30678757

RESUMO

BACKGROUND: Patent foramen ovale (PFO) closure is the gold standard for treating patients with cryptogenic stroke and PFO. However, scarce data exist on the long-term outcomes following PFO closure. OBJECTIVES: The purpose of this study was to determine the long-term (>10 years) clinical outcomes (death, ischemic, hemorrhagic events) following transcatheter PFO closure. METHODS: We included 201 consecutive patients (mean age: 47 ± 12 years, 51% women) who underwent PFO closure due to a cryptogenic embolism (stroke: 76%, transient ischemic attack [TIA]: 32%, systemic embolism: 1%). Echocardiographic examinations were performed at 1- to 6-month follow-up. Ischemic and bleeding events and antithrombotic medication were collected at a median follow-up of 12 years (range 10 to 17 years), and follow-up was complete in 96% of the patients. RESULTS: The PFO closure device was successfully implanted in all cases, and residual shunt was observed in 3.3% of patients at follow-up echocardiography. A total of 13 patients died at follow-up (all from noncardiovascular causes), and nondisabling stroke and TIA occurred in 2 and 6 patients, respectively (0.08 strokes per 100 patient-years; 0.26 TIAs per 100 patient-years). A history of thrombophilia (present in 15% of patients) tended to associate with a higher rate of ischemic events at follow-up (p = 0.067). Bleeding events occurred in 13 patients and were major (intracranial bleeding) in 4 patients (all of them under aspirin therapy at the time of the event). A total of 42 patients stopped the antithrombotic treatment at a median of 6 months (interquartile range 6 to 14 months) post-PFO closure, and none of them had any ischemic or bleeding episode after a mean of 10 ± 4 years following treatment cessation. CONCLUSIONS: PFO closure was associated with a low rate of ischemic events (stroke, 1%) at >10 years of follow-up. Major bleeding events occurred in 2% of the patients (all of them in patients on antiplatelet therapy). One-fifth of patients stopped the antithrombotic therapy during the follow-up period (the majority within the first-year post-PFO closure), and this was not associated with any increase in ischemic events at long-term follow-up.


Assuntos
Embolia/prevenção & controle , Forame Oval Patente/cirurgia , Ataque Isquêmico Transitório/prevenção & controle , Acidente Vascular Cerebral/prevenção & controle , Adulto , Embolia/etiologia , Feminino , Seguimentos , Forame Oval Patente/complicações , Hemorragia/induzido quimicamente , Humanos , Ataque Isquêmico Transitório/etiologia , Masculino , Pessoa de Meia-Idade , Inibidores da Agregação Plaquetária/efeitos adversos , Quebeque/epidemiologia , Prevenção Secundária , Acidente Vascular Cerebral/epidemiologia , Acidente Vascular Cerebral/etiologia
16.
Rev Sci Instrum ; 88(2): 025105, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28249524

RESUMO

The present study describes a sputtering and in situ vacuum electrical resistivity setup that allows a more efficient sputtering-oxidation coupling process for the fabrication of oxide compounds like vanadium dioxide, VO2. After the sputtering deposition of pure V thin films, the proposed setup enables the sample holder to be transferred from the sputtering to the in situ annealing + resistivity chamber without venting the whole system. The thermal oxidation of the V films was studied by implementing two different temperature cycles up to 550 °C, both in air (using a different resistivity setup) and vacuum conditions. Main results show that the proposed system is able to accurately follow the different temperature setpoints, presenting clean and low-noise resistivity curves. Furthermore, it is possible to identify the formation of different vanadium oxide phases in air, taking into account the distinct temperature cycles used. The metallic-like electrical properties of the annealed coatings are maintained in vacuum whereas those heated in air produce a vanadium oxide phase mixture.

17.
J R Soc Interface ; 12(110): 0495, 2015 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-26269232

RESUMO

This study investigates how the fingerpad hydrolipid film, shape, roughness and rigidity influence the friction when it rubs surfaces situated in the slippery psychophysical dimension. The studied counterparts comprised two 'real' (physical) surfaces and two 'virtual' surfaces. The latter were simulated with a tactile stimulator named STIMTAC. Thirteen women and 13 men rubbed their right forefingers against the different surfaces as their arms were displaced by a DC motor providing constant velocity and sliding distance. Tangential and normal forces were measured with a specific tribometer. The fingerpad hydrolipid film was characterized by Fourier transform infrared spectroscopy. The shape and roughness of fingers were extrapolated from replicas. Indentation measurements were carried out to determine fingerpad effective elastic modulus. A clear difference was observed between women and men in terms of friction behaviour. The concept of tactile frictional contrast (TFC) which was introduced quantifies an individual's propensity to distinguish two surfaces frictionally. The lipids/water ratio and water amount on the finger skin significantly influenced the TFC. A correlation was observed between the TFC and fingerpad roughness, i.e. the height of the fingerpad ridges. This is essentially owing to gender differences. A significant difference between men's and women's finger topography was also noted, because our results suggested that men have rougher fingers than women. The friction measurements did not correlate with the fingerpad curvature nor with the epidermal ridges' spatial period.


Assuntos
Módulo de Elasticidade , Dedos , Membranas Artificiais , Pele , Feminino , Humanos , Masculino , Propriedades de Superfície
18.
Nat Genet ; 46(11): 1245-9, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25282101

RESUMO

The pacemaking activity of specialized tissues in the heart and gut results in lifelong rhythmic contractions. Here we describe a new syndrome characterized by Chronic Atrial and Intestinal Dysrhythmia, termed CAID syndrome, in 16 French Canadians and 1 Swede. We show that a single shared homozygous founder mutation in SGOL1, a component of the cohesin complex, causes CAID syndrome. Cultured dermal fibroblasts from affected individuals showed accelerated cell cycle progression, a higher rate of senescence and enhanced activation of TGF-ß signaling. Karyotypes showed the typical railroad appearance of a centromeric cohesion defect. Tissues derived from affected individuals displayed pathological changes in both the enteric nervous system and smooth muscle. Morpholino-induced knockdown of sgol1 in zebrafish recapitulated the abnormalities seen in humans with CAID syndrome. Our findings identify CAID syndrome as a novel generalized dysrhythmia, suggesting a new role for SGOL1 and the cohesin complex in mediating the integrity of human cardiac and gut rhythm.


Assuntos
Anormalidades Múltiplas/genética , Arritmias Cardíacas/genética , Proteínas de Ciclo Celular/genética , Proteínas Cromossômicas não Histona/genética , Enteropatias/genética , Contração Muscular/fisiologia , Transdução de Sinais/genética , Animais , Arritmias Cardíacas/patologia , Ciclo Celular/genética , Sistema Nervoso Entérico/patologia , Fibroblastos , Efeito Fundador , Trato Gastrointestinal/fisiopatologia , Técnicas de Silenciamento de Genes , Humanos , Enteropatias/fisiopatologia , Cariotipagem , Contração Muscular/genética , Músculo Liso Vascular/patologia , Mutação/genética , Quebeque , Síndrome , Fator de Crescimento Transformador beta/metabolismo , Peixe-Zebra , Coesinas
19.
Heart Rhythm ; 11(8): 1426-32, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24769425

RESUMO

BACKGROUND: Permanent junctional reciprocating tachycardia (PJRT) is an uncommon form of supraventricular tachycardia in children. Treatment of this arrhythmia has been considered difficult because of a high medication failure rate and risk of cardiomyopathy. Outcomes in the current era of interventional treatment with catheter ablation have not been published. OBJECTIVE: To describe the presentation and clinical course of PJRT in children. METHODS: This is a retrospective review of 194 pediatric patients with PJRT managed at 11 institutions between January 2000 and December 2010. RESULTS: The median age at diagnosis was 3.2 months, including 110 infants (57%; aged <1 year). PJRT was incessant in 47%. The ratio of RP interval to cycle length was higher with incessant than with nonincessant tachycardia. Tachycardia-induced cardiomyopathy was observed in 18%. Antiarrhythmic medications were used for initial management in 76%, while catheter ablation was used initially in only 10%. Medications achieved complete resolution in 23% with clinical benefit in an additional 47%. Overall, 140 patients underwent 175 catheter ablation procedures with a success rate of 90%. There were complications in 9% with no major complications reported. Patients were followed for a median of 45.1 months. Regardless of treatment modality, normal sinus rhythm was present in 90% at last follow-up. Spontaneous resolution occurred in 12% of the patients. CONCLUSION: PJRT in children is frequently incessant at the time of diagnosis and may be associated with tachycardia-induced cardiomyopathy. Antiarrhythmic medications result in complete control in few patients. Catheter ablation is effective, and serious complications are rare.


Assuntos
Eletrocardiografia , Sistema de Condução Cardíaco/fisiopatologia , Taquicardia Reciprocante/fisiopatologia , Adolescente , Canadá/epidemiologia , Criança , Pré-Escolar , Feminino , Seguimentos , Humanos , Incidência , Lactente , Recém-Nascido , Masculino , Estudos Retrospectivos , Taquicardia Reciprocante/epidemiologia , Estados Unidos/epidemiologia
20.
Can J Cardiol ; 27(3): 389.e19-24, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21507602

RESUMO

BACKGROUND: The management of pediatric discrete subaortic stenosis remains controversial. OBJECTIVES: Document the natural history and surgical outcomes for discrete subaortic stenosis to adolescence. METHODS: Retrospective review of clinical and echocardiographic findings in 74 patients diagnosed in childhood between 1985 and 1998. RESULTS: Twenty-five patients were followed only medically for 9.4 ± 0.9 years to 15.9 ± 0.6 years of age. Their echocardiographic left ventricular outflow peak gradient did not progress, 19 ± 1.4 (SEM) vs 20 ± 2.3 mm Hg. The proportion with aortic insufficiency (AI) increased (4% to 52%). Forty-nine patients were operated for discrete subaortic stenosis at 7.8 ± 0.6 years. Their peak gradient at diagnosis was 36 ± 3 mm Hg with AI in 33%. Preoperatively their peak gradient progressed to 60 ± 5 mm Hg with AI in 82%. Assessment 6.2 ± 0.5 years postoperativly showed a peak gradient of 14 ± 2 mm Hg with AI in 88%. Ten patients required reoperation for recurrent discrete subaortic stenosis, 3 acquired complete heart block, and 1 developed endocarditis. There was no mortality. At diagnosis, surgical patients were younger, had greater peak gradients, and greater incidence of AI, than those followed only medically. The progression of discrete subaortic stenosis was positively associated with severity of obstruction and negatively associated with older age at diagnosis. The risk of having surgery over time was associated with greater preoperative obstruction and presence of AI. CONCLUSIONS: Many pediatric patients with mild discrete subaortic stenosis exhibit little progression of obstruction and need not undergo immediate surgery. Others with more severe stenosis may progress precipitously and will benefit from early resection.


Assuntos
Estenose Subaórtica Fixa/terapia , Procedimentos Cirúrgicos Vasculares/métodos , Vasodilatadores/uso terapêutico , Adolescente , Fatores Etários , Criança , Pré-Escolar , Estudos de Coortes , Estenose Subaórtica Fixa/congênito , Estenose Subaórtica Fixa/diagnóstico por imagem , Progressão da Doença , Ecocardiografia Doppler/métodos , Feminino , Seguimentos , Humanos , Masculino , Monitorização Fisiológica/métodos , Análise Multivariada , Modelos de Riscos Proporcionais , Quebeque , Análise de Regressão , Estudos Retrospectivos , Medição de Risco , Índice de Gravidade de Doença , Fatores Sexuais , Fatores de Tempo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA