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This corrects the article DOI: 10.1103/PhysRevLett.120.162001.
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Cardiac magnetic resonance (MR) imaging is one of the most rigorous form of imaging to assess cardiac function in vivo. Strain analysis allows comprehensive assessment of diastolic myocardial function, which is not indicated by measuring systolic functional parameters using with a normal cine imaging module. Due to the small heart size in mice, it is not possible to perform proper tagged imaging to assess strain. Here, we developed a novel deep learning approach for automated quantification of strain from cardiac cine MR images. Our framework starts by an accurate localization of the LV blood pool center-point using a fully convolutional neural network (FCN) architecture. Then, a region of interest (ROI) that contains the LV is extracted from all heart sections. The extracted ROIs are used for the segmentation of the LV cavity and myocardium via a novel FCN architecture. For strain analysis, we developed a Laplace-based approach to track the LV wall points by solving the Laplace equation between the LV contours of each two successive image frames over the cardiac cycle. Following tracking, the strain estimation is performed using the Lagrangian-based approach. This new automated system for strain analysis was validated by comparing the outcome of these analysis with the tagged MR images from the same mice. There were no significant differences between the strain data obtained from our algorithm using cine compared to tagged MR imaging. Furthermore, we demonstrated that our new algorithm can determine the strain differences between normal and diseased hearts.
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Cardiopatías/diagnóstico por imagen , Ventrículos Cardíacos/diagnóstico por imagen , Corazón/diagnóstico por imagen , Imagen por Resonancia Cinemagnética , Algoritmos , Animales , Corazón/fisiopatología , Cardiopatías/fisiopatología , Ventrículos Cardíacos/patología , Humanos , Interpretación de Imagen Asistida por Computador , Procesamiento de Imagen Asistido por Computador , Ratones , Redes Neurales de la ComputaciónRESUMEN
OBJECTIVES: The aim of this review is to explore the impact of educational interventions on clinicians' knowledge of radiation protection. KEY FINDINGS: Following a comprehensive search of MEDLINE and EMBASE from 2000 to 2018, 1795 studies were identified, eight of which met the criteria for this review. All eight studies utilised pretest-posttest designs and involved the education of medical students or doctors. All studies reported an increase in participants' knowledge of radiation protection, five of which were statistically significant. In two studies, over half of participants stated that education received would impact on their future imaging requesting practice. CONCLUSION: Whilst a range of educational interventions have been shown to improve knowledge of radiation protection, there was wide variation in the study settings and type of educational programmes delivered. No studies assessed long-term knowledge retention or the impact on clinical practice. Therefore, robust research is needed to accurately measure the impact of educational programmes on knowledge of radiation protection in the UK and the implications this may have on referral practices. IMPLICATIONS FOR PRACTICE: This review revealed that educational interventions are effective in increasing participants' knowledge levels of radiation protection. It is necessary to assess and ensure that this improvement in knowledge actually translates into an impact on referral practice/behaviour. The ideal outcome being that fewer unnecessary examinations are requested and our patients are protected from a needless increased radiation burden.
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Competencia Clínica/estadística & datos numéricos , Protección Radiológica/métodos , Radiología/educación , HumanosRESUMEN
Adults with intellectual disabilities in England experience health inequalities. They are more likely than their non-disabled peers to be obese and at risk of serious medical conditions such as heart disease, stroke and type 2 diabetes. This semi-qualitative study engaged adults with intellectual disabilities in a co-production process to explore their perceived barriers and facilitators to eating well, living well and weight management. Nineteen participants with intellectual disabilities took part in four focus groups and one wider group discussion. They were supported by eight of their carers or support workers. Several barriers were identified including personal income restrictions, carers' and support workers' unmet training needs, a lack of accessible information, inaccessible services and societal barriers such as the widespread advertising of less healthy foodstuffs. A key theme of frustration with barriers emerged from analysis of participants' responses. Practical solutions suggested by participants included provision of clear and accessible healthy lifestyle information, reasonable adjustments to services, training, 'buddying' support systems or schemes and collaborative working to improve policy and practice.
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Conducta Alimentaria/psicología , Conductas Relacionadas con la Salud , Discapacidad Intelectual/psicología , Obesidad/terapia , Adulto , Investigación Participativa Basada en la Comunidad , Inglaterra , Femenino , Humanos , Masculino , Investigación CualitativaRESUMEN
We present the next-to-leading-order QCD corrections to the production of a Higgs boson in association with one jet at the LHC including the full top-quark mass dependence. The mass of the bottom quark is neglected. The two-loop integrals appearing in the virtual contribution are calculated numerically using the method of sector decomposition. We study the Higgs boson transverse momentum distribution, focusing on the high p_{t,H} region, where the top-quark loop is resolved. We find that the next-to-leading-order QCD corrections are large but that the ratio of the next-to-leading-order to leading-order result is similar to that obtained by computing in the limit of large top-quark mass.
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Colossal magnetoresistance (CMR) is demonstrated at terahertz (THz) frequencies by using terahertz time-domain magnetospectroscopy to examine vertically aligned nanocomposites (VANs) and planar thin films of La0.7Sr0.3MnO3. At the Curie temperature (room temperature), the THz conductivity of the VAN was dramatically enhanced by over 2 orders of magnitude under the application of a magnetic field with a non-Drude THz conductivity that increased with frequency. The direct current (dc) CMR of the VAN is controlled by extrinsic magnetotransport mechanisms such as spin-polarized tunneling between nanograins. In contrast, we find that THz CMR is dominated by intrinsic, intragrain transport: the mean free path was smaller than the nanocolumn size, and the planar thin-film exhibited similar THz CMR to the VAN. Surprisingly, the observed colossal THz magnetoresistance suggests that the magnetoresistance can be large for alternating current motion on nanometer length scales, even when the magnetoresistance is negligible on the macroscopic length scales probed by dc transport. This suggests that colossal magnetoresistance at THz frequencies may find use in nanoelectronics and in THz optical components controlled by magnetic fields. The VAN can be scaled in thickness while retaining a high structural quality and offers a larger THz CMR at room temperature than the planar film.
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This corrects the article DOI: 10.1103/PhysRevLett.117.012001.
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We present the calculation of the cross section and invariant mass distribution for Higgs boson pair production in gluon fusion at next-to-leading order (NLO) in QCD. Top-quark masses are fully taken into account throughout the calculation. The virtual two-loop amplitude has been generated using an extension of the program GoSam supplemented with an interface to Reduze for the integral reduction. The occurring integrals have been calculated numerically using the program SecDec. Our results, including the full top-quark mass dependence for the first time, allow us to assess the validity of various approximations proposed in the literature, which we also recalculate. We find substantial deviations between the NLO result and the different approximations, which emphasizes the importance of including the full top-quark mass dependence at NLO.
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Sensory gating is a neurophysiological measure of inhibition that is characterised by a reduction in the P50 event-related potential to a repeated identical stimulus. The objective of this work was to determine the cognitive mechanisms that relate to the neurological phenomenon of auditory sensory gating. Sixty participants underwent a battery of 10 cognitive tasks, including qualitatively different measures of attentional inhibition, working memory, and fluid intelligence. Participants additionally completed a paired-stimulus paradigm as a measure of auditory sensory gating. A correlational analysis revealed that several tasks correlated significantly with sensory gating. However once fluid intelligence and working memory were accounted for, only a measure of latent inhibition and accuracy scores on the continuous performance task showed significant sensitivity to sensory gating. We conclude that sensory gating reflects the identification of goal-irrelevant information at the encoding (input) stage and the subsequent ability to selectively attend to goal-relevant information based on that previous identification.
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Percepción Auditiva/fisiología , Cognición/fisiología , Potenciales Evocados Auditivos/fisiología , Función Ejecutiva/fisiología , Inhibición Neural/fisiología , Filtrado Sensorial/fisiología , Adulto , Atención/fisiología , Electroencefalografía , Femenino , Humanos , Inhibición Psicológica , Masculino , Memoria a Corto Plazo/fisiología , Adulto JovenRESUMEN
Magnetically induced ferroelectric multiferroics present an exciting new paradigm in the design of multifunctional materials, by intimately coupling magnetic and polar order. Magnetoelectricity creates a novel quasiparticle excitation--the electromagnon--at terahertz frequencies, with spectral signatures that unveil important spin interactions. To date, electromagnons have been discovered at low temperature (<70 K) and predominantly in rare-earth compounds such as RMnO3. Here we demonstrate using terahertz time-domain spectroscopy that intersublattice exchange in the improper multiferroic cupric oxide (CuO) creates electromagnons at substantially elevated temperatures (213-230 K). Dynamic magnetoelectric coupling can therefore be achieved in materials, such as CuO, that exhibit minimal static cross-coupling. The electromagnon strength and energy track the static polarization, highlighting the importance of the underlying cycloidal spin structure. Polarized neutron scattering and terahertz spectroscopy identify a magnon in the antiferromagnetic ground state, with a temperature dependence that suggests a significant role for biquadratic exchange.
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Cobre/química , Compuestos de Hierro/química , Magnetismo/instrumentación , Magnetismo/métodos , TemperaturaRESUMEN
Polarization-resolved terahertz (THz) time-domain spectroscopy was utilized to examine the complex refractive index of lanthanum aluminate (LaAlO3), a rhombohedrally distorted perovskite that exhibits crystallographic twin domains. The uniaxial anisotropy of the refractive index was quantified. The ellipticity of THz radiation pulses after transmission through single domains indicated that LaAlO3 can be used as a quarter- or half-wave plate. The effective anisotropy of [001]-oriented LaAlO3 was found to be reduced when the material exhibited multiple, narrow twin domains.
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Accurately tracing the optic radiations in living humans has important implications for studying the relationship between tract structure or integrity and visual function, in health and disease. Probabilistic tractography is an established method for tracing white matter tracts in humans. Prior studies have used this method to trace the optic radiations, but operator-dependent factors, particularly variability in seed voxel placement and choice of connectivity threshold to select between tract and non-tract voxels, remain potential causes of significant variability. Methods using prior information to modify tract images risk introducing error by underestimating individual variability, particularly in subjects with abnormal anatomy. Finally, existing methods lack thorough validation against a histological standard, causing difficulty in evaluating individual methods, and quantitatively comparing methods. Here we describe a method for producing binary optic radiation images using an existing, well-validated tractography method. All stages are automated, including mask image generation, and thresholds are objectively selected by comparing tract images with existing probabilistic histological data in stereotaxic space. Data from two subject groups are presented; the first used to derive analysis parameters, and the second to test these parameters in an independent sample. Validation utilised a novel variant of receiver operating characteristic analysis, providing both justification for this method and a metric by which tractography methods might be compared generally. The resulting tracts match the histological data well; images generated in individuals matched the histological group data about as well as did images derived in individuals from that histological data set, with a low false positive rate.
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Mapeo Encefálico/métodos , Encéfalo/anatomía & histología , Vías Visuales/anatomía & histología , Adulto , Anciano , Área Bajo la Curva , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Curva ROC , Adulto JovenRESUMEN
OBJECTIVE: To investigate the force retention, and rates of space closure achieved by elastomeric chain and nickel titanium coil springs. DESIGN: Randomized clinical trial. SETTING: Eastman Dental Hospital, London and Queen Mary's University Hospital, Roehampton, 1998-2000. SUBJECTS, MATERIALS AND METHODS: Twenty-two orthodontic patients, wearing the pre-adjusted edgewise appliance undergoing space closure in opposing quadrants, using sliding mechanics on 0.019 x 0.025-inch posted stainless steel archwires. Medium-spaced elastomeric chain [Durachain, OrthoCare (UK) Ltd., Bradford, UK] and 9-mm nickel titanium coil springs [OrthoCare (UK) Ltd.] were placed in opposing quadrants for 15 patients. Elastomeric chain only was used in a further seven patients. The initial forces on placement and residual forces at the subsequent visit were measured with a dial push-pull gauge [Orthocare (UK) Ltd]. Study models of eight patients were taken before and after space closure, from which measurements were made to establish mean space closure. MAIN OUTCOME MEASURES: The forces were measured in grammes and space closure in millimetres. RESULTS: Fifty-nine per cent (31/53) of the elastomeric sample maintained at least 50 per cent of the initial force over a time period of 1-15 weeks. No sample lost all its force, and the mean loss was 47 per cent (range: 0-76 per cent). Nickel titanium coil springs lost force rapidly over 6 weeks, following that force levels plateaued. Forty-six per cent (12/26) maintained at least 50 per cent of their initial force over a time period of 1-22 weeks, and mean force loss was 48 per cent (range: 12-68 per cent). The rate of mean weekly space closure for elastomeric chain was 0.21 mm and for nickel titanium coil springs 0.26 mm. There was no relationship between the initial force applied and rate of space closure. None of the sample failed during the study period giving a 100 per cent response rate. CONCLUSIONS: In clinical use, the force retention of elastomeric chain was better than previously concluded. High initial forces resulted in high force decay. Nickel titanium coil springs and elastomeric chain closed spaces at a similar rate.
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Aparatos Ortodóncicos , Cierre del Espacio Ortodóncico , Adolescente , Niño , Aleaciones Dentales , Análisis del Estrés Dental , Elastómeros , Humanos , Níquel , Diseño de Aparato Ortodóncico , TitanioRESUMEN
This study investigated the effects of reconditioning on the slot dimensions and the static frictional resistance of stainless steel brackets at 0, 5, and 10 degrees bracket/archwire angulation. A sample of 45 used, commercially reconditioned 0.018 x 0.030 inch stainless steel standard edgewise brackets was compared with a matched sample of 45 new brackets. The slot dimensions of 15 new and 15 reconditioned brackets were examined using a photomicroscope. With new brackets both the occluso-gingival slot width (mean = 0.0197 inch) and slot depth (mean = 0.0304 inch) exceeded the manufacturer's nominal dimensions of 0.018 x 0.030 inch. The reconditioning process resulted in a further increase in slot width (mean = 0.0205 inch), which was statistically significant (P = 0.028), and a reduction in slot depth (mean = 0.0291 inch), which was highly statistically significant (P = 0.002). This may be attributable to preferential metal removal by the electro-polishing phase of the reconditioning process. Friction testing of 30 new and 30 reconditioned brackets demonstrated that both showed an increase in binding effects as the bracket/archwire angulation was increased from 0 to 5-10 degrees. However, the changes in slot dimensions secondary to reconditioning did not result in a statistically significant difference in mean static frictional resistance when the two bracket types were compared. Although the brackets were altered physically by the reconditioning process, their performance during simulated sliding mechanics was not adversely affected. This implies that reconditioning may not result in clinically significant effects.
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Equipo Reutilizado , Soportes Ortodóncicos , Pulido Dental , Análisis del Estrés Dental , Fricción , Acero Inoxidable , Estadísticas no ParamétricasRESUMEN
We have previously demonstrated that simvastatin attenuates myocardial cell necrosis after acute myocardial ischemia and reperfusion via induction of endothelial cell NO synthase. However, it remains unknown whether the cardioprotective effects of statins can persist after extended periods of reperfusion. Furthermore, it is unknown whether simvastatin therapy can attenuate postischemic cardiac dysfunction. Pretreatment with simvastatin attenuated myocardial injury after 30 minutes of myocardial ischemia and 24 hours of reperfusion. However, the protective effects are not recognized unless simvastatin is given at least 3 hours before myocardial ischemia. Subsequently, we pretreated mice with vehicle or simvastatin and subjected the mice to 30 minutes of myocardial ischemia and 6 months of reperfusion. Myocardial infarct size (percentage of left ventricle) was significantly reduced by 51% in the simvastatin-treated group compared with the vehicle-treated group. Left ventricular diastolic and systolic dilatation was significantly (P<0.05) reduced in simvastatin-treated mice compared with vehicle-treated mice. Additionally, the decrement in fractional shortening after 6 months of reperfusion was minimized in simvastatin-treated mice (P=NS versus baseline) compared with vehicle-treated mice (P<0.05 versus baseline). Left ventricular end-diastolic pressure was significantly (P<0.01) elevated in vehicle-treated mice (21+/-4 mm Hg) but not simvastatin-treated mice (5+/-2 mm Hg) compared with baseline values. These data demonstrate that simvastatin treatment before myocardial ischemia attenuates infarct size and preserves myocardial function after chronic reperfusion in mice.
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Anticolesterolemiantes/administración & dosificación , Infarto del Miocardio/prevención & control , Isquemia Miocárdica/tratamiento farmacológico , Premedicación , Simvastatina/administración & dosificación , Disfunción Ventricular Izquierda/prevención & control , Animales , Hemodinámica/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos C57BL , Infarto del Miocardio/etiología , Isquemia Miocárdica/complicaciones , Isquemia Miocárdica/fisiopatología , Reperfusión Miocárdica , Ultrasonografía , Disfunción Ventricular Izquierda/diagnóstico por imagen , Disfunción Ventricular Izquierda/etiologíaRESUMEN
The Plasmodium berghei-infected mouse model is a well-recognized model for human cerebral malaria. Mice infected with P. berghei exhibit (i) metabolic acidosis (pH < 7.3) associated with elevated plasma lactate concentrations, (ii) significant (P < 0.05) vascular leakage in their lungs, hearts, kidneys, and brains, (ii) significantly (P < 0.05) higher cell and serum glutamate concentrations, and (iv) significantly (P < 0.05) lower mean arterial blood pressures. Because these complications are similar to those of septic shock, the simplest interpretation of these findings is that the mice develop shock brought on by the P. berghei infection. To determine whether the immune system and specifically CD8(+) T cells mediate the key features of shock during P. berghei malaria, we depleted CD8(+) T cells by monoclonal antibody (mAb) treatment and assessed the complications of malarial shock. P. berghei-infected mice depleted of CD8(+) T cells by mAb treatment had significantly reduced vascular leakage in their hearts, brains, lungs, and kidneys compared with infected controls treated with rat immunoglobulin G. CD8-depleted mice were significantly (P < 0.05) protected from lactic acidosis, glutamate buildup, and diminished HCO(3)(-) levels. Although the blood pressure decreased in anti-CD8 mAb-treated mice infected with P. berghei, the cardiac output, as assessed by echocardiography, was similar to that of uninfected control mice. Collectively, our results indicate that (i) pathogenesis similar to septic shock occurs during experimental P. berghei malaria, (ii) respiratory distress with lactic acidosis occurs during P. berghei malaria, and (iii) most components of circulatory shock are ameliorated by depletion of CD8(+) T cells.
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Linfocitos T CD8-positivos/inmunología , Depleción Linfocítica , Malaria/inmunología , Plasmodium berghei/inmunología , Choque/inmunología , Acidosis Láctica , Adenosina Trifosfatasas/sangre , Animales , Proteínas de Transporte de Anión , Permeabilidad Capilar , Gasto Cardíaco , Edema , Ácido Glutámico/sangre , Ácido Láctico/sangre , Malaria/complicaciones , Modelos Inmunológicos , Choque/etiología , Choque/terapiaRESUMEN
Exercise/physical activity is increasingly being advocated as a positive addition to the treatment regimen of HIV-positive individuals. We investigated the effects of 10 weeks' aerobic and resistance training on individuals with HIV-related lipodystrophy. These individuals demonstrated an improvement in exercise tolerance, body composition and blood lipid profiles. Potentially, such changes may contribute to an amelioration of some of the adverse metabolic effects associated with highly active antiretroviral therapy.
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Composición Corporal , Terapia por Ejercicio , Infecciones por VIH/complicaciones , Hiperlipidemias/terapia , Lipodistrofia/terapia , Adulto , Terapia Antirretroviral Altamente Activa/efectos adversos , Colesterol/sangre , Tolerancia al Ejercicio , Femenino , Infecciones por VIH/terapia , Humanos , Lipodistrofia/diagnóstico , Masculino , Persona de Mediana Edad , Triglicéridos/sangreRESUMEN
A known risk factor for the development of coronary artery disease and subsequent myocardial infarction is hypercholesterolaemia. The widespread nature of this phenomenon in the western world has led to the development of agents which reduce serum cholesterol levels. One such class of agents, HMG-CoA reductase inhibitors (statins) are very effective in cholesterol reduction. Recently, clinical and experimental evidence has amassed suggesting that patients taking statins receive cardiovascular benefits that occur independent of cholesterol reduction. Experimental data suggest that statins may increase levels of nitric oxide (NO) in vivo. This review will address the 'cholesterol-independent' vasculoprotective and cardioprotective effects of statins in animal models. Upon completion, the reader will be familiar with the proposed cholesterol-independent pathways of statins and understand that the cholesterol-independent benefits may arise from enhanced production of NO.
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Cardiotónicos/farmacología , Inhibidores de Hidroximetilglutaril-CoA Reductasas/farmacología , Infarto del Miocardio/tratamiento farmacológico , Animales , Colesterol/sangre , Infarto del Miocardio/metabolismo , Óxido Nítrico/metabolismoRESUMEN
Prevention of peri-bracket decalcification is essentially mediated by effective oral hygiene, which is patient dependent. The potential to compensate for poor oral hygiene may be through the release of free fluoride ions from direct bonding agents. It is well established that glass ionomer cements (GICs) release free fluoride ions which may be replenished by exposure to fluoride containing solutions. The aim of this ex vivo study was to compare the fluoride release and absorption profiles of a recently developed low fusion, monophase GIC, Limerick glass, with two materials in common clinical use, namely, Fuji-Ortho L.C. and Concise. Ten test specimens of each material were fabricated and stored in deionized water at 37 degrees C. The concentration of fluoride release was measured daily for the first 7 days after immersion and then weekly for 5 weeks. On day 42 the test specimens were recharged in 2 per cent sodium fluoride solution and fluoride release was measured initially after 24 hours and then every 48 hours. The recharge regimen was repeated for 3 weeks. Both Limerick glass and Fuji-Ortho L.C. demonstrated the characteristic fluoride release pattern of GIC with a rapid elution of fluoride after the first 24 hours followed by a more gradual release profile over the following 2 weeks. Fuji-Ortho L.C. released the greatest quantity of fluoride but the release profile of Limerick glass was more sustained. Concise released negligible amounts of fluoride. Limerick glass and Fuji-Ortho L.C. showed an increase (P < 0.01) in fluoride release following exposure to 2 per cent sodium fluoride that decreased both with time and subsequent exposures to fluoride supplement.