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On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.
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BACKGROUND: Teeth affected with enamel defects (EDs) are at an increased risk of dental caries. In spite of improving oral health status overall in Australia, Indigenous Australians still experience higher rates of dental caries than non-Indigenous Australians. This study reports on the prevalence of EDs and dental caries experience among Indigenous children in the Kimberley region of Western Australia. METHODS: Health status of all the primary teeth (ICDAS II criteria) and the presence of EDs on index teeth (modified Dental Defects of Enamel index; DDE) of young Indigenous children who participated in a 2-arm intervention trial was recorded. Generalized estimating equations were used to estimate the association between EDs and dental caries and effect estimates were presented as odds ratios and associated 95% confidence intervals. RESULTS: Person-level prevalence, from 237 children (mean age 3.6 years, standard deviation 1.7) assessed for EDs, was 58% and tooth-level prevalence was 24%. Teeth affected with demarcated or diffuse defects were associated with a twofold higher odds of having caries experience, odds ratio (OR) 2.5, 95% confidence interval (CI) 1.7-3.7 and OR 2.7, 95% CI 1.7-4.0 respectively. CONCLUSIONS: The presence of EDs among young Indigenous children was associated with a higher odds of caries experience among affected teeth.
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Caries Dental , Hipoplasia del Esmalte Dental , Humanos , Niño , Preescolar , Hipoplasia del Esmalte Dental/epidemiología , Caries Dental/epidemiología , Australia Occidental , Australia , Esmalte Dental , Diente Primario , PrevalenciaRESUMEN
For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.
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BACKGROUND AND PURPOSE: Intra-arterial DSA has been traditionally used for confirmation of cure following gamma knife radiosurgery for AVMs. Our aim was to evaluate whether 4D arterial spin-labeling MRA and contrast-enhanced time-resolved MRA in combination can be an alternative to DSA for confirmation of AVM obliteration following gamma knife radiosurgery. MATERIALS AND METHODS: In this prospective study, 30 patients undergoing DSA for confirmation of obliteration following gamma knife radiosurgery for AVMs (criterion standard) also underwent MRA, including arterial spin-labeling MRA and contrast-enhanced time-resolved MRA. One dataset was technically unsatisfactory, and the case was excluded. The DSA and MRA datasets of 29 patients were independently and blindly evaluated by 2 observers regarding the presence/absence of residual AVMs. RESULTS: The mean time between gamma knife radiosurgery and follow-up DSA/MRA was 53 months (95% CI, 42-64 months; range, 22-168 months). MRA total scanning time was 9 minutes and 17 seconds. Residual AVMs were detected on DSA in 9 subjects (obliteration rate = 69%). All residual AVMs were detected on at least 1 MRA sequence. Arterial spin-labeling MRA and contrast-enhanced time-resolved MRA showed excellent specificity and positive predictive values individually (100%). However, their sensitivity and negative predictive values were suboptimal due to 1 false-negative with arterial spin-labeling MRA and 2 with contrast-enhanced time-resolved MRA (sensitivity = 88% and 77%, negative predictive values = 95% and 90%, respectively). Both sensitivity and negative predictive values increased to 100% if a composite assessment of both MRA sequences was performed. Diagnostic accuracy (receiver operating characteristic) and agreement (κ) are maximized using arterial spin-labeling MRA and contrast-enhanced time-resolved MRA in combination (area under receiver operating characteristic curve = 1, P < .001; κ = 1, P < .001, respectively). CONCLUSIONS: Combining arterial spin-labeling MRA with contrast-enhanced time-resolved MRA holds promise as an alternative to DSA for confirmation of obliteration following gamma knife radiosurgery for brain AVMs, having provided 100% sensitivity and specificity in the study. Their combined use also enables reliable characterization of residual lesions.
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Radiocirugia , Adolescente , Adulto , Anciano , Encéfalo , Femenino , Humanos , Malformaciones Arteriovenosas Intracraneales/diagnóstico por imagen , Malformaciones Arteriovenosas Intracraneales/cirugía , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Estudios Retrospectivos , Marcadores de Spin , Resultado del Tratamiento , Adulto JovenRESUMEN
INTRODUCTION: The management of early childhood caries (ECC) is challenging. OBJECTIVES: A model of care based on Atraumatic Restorative Treatment and the Hall Technique (ART-HT) to manage ECC was evaluated among remote Aboriginal communities in Australia. METHODS: Aboriginal communities in the North-West of Western Australia were invited to participate and consenting communities were randomized into early or delayed intervention for the management of ECC. Children were examined at baseline and at the 11-mo follow-up. The early intervention group (test) was provided with the ART-based dental care at baseline while the delayed intervention group (control) was advised to seek care through the usual care options available within the community. At follow-up, both groups were examined by calibrated examiners, and were offered care using the ART-HT approach. Changes from baseline to follow-up in caries experience were tested using paired tests. Multivariate analysis after multiple imputation of missing data used generalised estimating equation (GEE) controlling for clustering within communities. RESULTS: A total of 25 communities and 338 children (mean age = 3.6 y, SD 1.7) participated in the study (test = 177). At follow-up, 231 children were examined (68% retention, test = 125). At follow-up, children in the test group had more filled teeth (test filled teeth = 1.2, control filled teeth = 0.2, P < 0.001) and decreased levels of decayed teeth (mean test = 0.7 fewer teeth with decay, mean control = 1.0 more tooth with decay, P < 0.001). GEE analysis controlled for baseline caries experience, age, sex, and community water fluoride levels found increased rates of untreated decayed teeth (RR = 1.4, P = 0.02) and decreased rates of filled teeth (RR = 0.2, P < 0.001) at follow-up among the control group. CONCLUSION: A model of care relying on the principles of minimally invasive atraumatic approaches enabled the delivery of effective dental services to young children (<6 y) in remote Aboriginal Australian communities resulting in increased levels of care and improved oral health. KNOWLEDGE TRANSFER STATEMENT: This cluster-randomized trial tested a multi-component model of dental care to young children with ECC in remote Aboriginal communities in Australia. The intervention, based on the atraumatic approaches using minimally invasive techniques encompassing preventive care, Atraumatic Restorative Treatment and the Hall Technique (ART-HT), delivered more restorative care and reduced the incidence of caries. This model of care was more effective than available standard care and should be incorporated into mainstream service delivery programs.
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Tratamiento Restaurativo Atraumático Dental , Caries Dental , Australia/epidemiología , Niño , Preescolar , Caries Dental/terapia , Restauración Dental Permanente , Humanos , Salud BucalRESUMEN
OBJECTIVE: We hypothesised that a multi-compartment magnetic resonance imaging (MRI) technique that is sensitive to fetal blood oxygenation would identify changes in placental blood volume and fetal blood oxygenation in pregnancies complicated by early-onset fetal growth restriction (FGR). DESIGN: Case-control study. SETTING: London, UK. POPULATION: Women with uncomplicated pregnancies (estimated fetal weight [EFW] >10th centile for gestational age [GA] and normal maternal and fetal Doppler ultrasound, n = 12) or early-onset FGR (EFW <3rd centile with or without abnormal Doppler ultrasound <32 weeks GA, n = 12) were studied. METHODS: All women underwent MRI examination. Using a multi-compartment MRI technique, we quantified fetal and maternal blood volume and feto-placental blood oxygenation. MAIN OUTCOME MEASURES: Disease severity was stratified according to Doppler pulsatility index and the relationship to the MRI parameters was investigated, including the influence of GA at scan. RESULTS: The FGR group (mean GA 27+5 weeks, range 24+2 to 33+6 weeks) had a significantly lower EFW compared with the control group (mean GA 29+1 weeks; -705 g, 95% CI -353 to -1057 g). MRI-derived feto-placental oxygen saturation was higher in controls compared with FGR (75 ± 9.6% versus 56 ± 16.2%, P = 0.02, 95% CI 7.8-30.3%). Feto-placental oxygen saturation estimation correlated strongly with GA at scan in controls (r = -0.83). CONCLUSION: Using a novel multimodal MRI protocol we demonstrated reduced feto-placental blood oxygen saturation in pregnancies complicated by early-onset FGR. The degree of abnormality correlated with disease severity defined by ultrasound Doppler findings. Gestational age-dependent changes in oxygen saturation were also present in normal pregnancies. TWEETABLE ABSTRACT: MRI reveals differences in feto-placental oxygen saturation between normal and FGR pregnancy that is associated with disease severity.
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Retardo del Crecimiento Fetal/diagnóstico por imagen , Imagen por Resonancia Magnética , Oxígeno/sangre , Placenta/diagnóstico por imagen , Circulación Placentaria/fisiología , Adulto , Estudios de Casos y Controles , Estudios de Cohortes , Femenino , Retardo del Crecimiento Fetal/sangre , Retardo del Crecimiento Fetal/fisiopatología , Edad Gestacional , Humanos , Placenta/irrigación sanguínea , Embarazo , Diagnóstico PrenatalRESUMEN
The magnetisation reversal behaviour as a function of composition was studied in low rare earth concentration alloys. 30 nm thick rare earth:transition-metal films of composition GdxCo100-x, GdxFe100-x and Gdx(Co50Fe50)100-x were prepared by magnetron sputtering, where x ranged from 4 to 13 atomic%. Magnetisation behaviour was studied using MOKE and Hall hysteresis measurements. The magnetic reversal behaviour as a function of Gd content is strongly dependent on the transition metal. With increasing Gd content the film structure transitions from crystalline to amorphous and the saturation magnetisation decreases linearly. For GdCo, the reversal field, Hc, increases by less than a factor of two with Gd doping of 11%, while for Fe, the coercivity falls by a factor of ten with 8% Gd. This may be attributed to changes in the crystalline morphology. GdCoFe shows a similar trend with Gd doping for the in-plane reversal field to that of GdFe. With 13% Gd in Fe there is evidence indicating the presence of a weak perpendicular magnetic anisotropy, PMA. With Gd doping the anomalous Hall resistivity of Co, Fe and CoFe increases significantly with the largest increase observed for GdCoFe.
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OBJECTIVE: The importance of subcortical pathways to functional motor recovery after spinal cord injury (SCI) has been demonstrated in multiple animal models. The current study evaluated descending interlimb influence on lumbosacral motor excitability after chronic SCI in humans. METHODS: Ulnar nerve stimulation and transcutaneous electrical spinal stimulation were used in a condition-test paradigm to evaluate the presence of interlimb connections linking the cervical and lumbosacral spinal segments in non-injured (n=15) and spinal cord injured (SCI) (n=18) participants. RESULTS: Potentiation of spinally evoked motor responses (sEMRs) by ulnar nerve conditioning was observed in 7/7 SCI participants with volitional leg muscle activation, and in 6/11 SCI participants with no volitional activation. Of these six, conditioning of sEMRs was present only when the neurological level of injury was rostral to the ulnar innervation entry zones. CONCLUSIONS: Descending modulation of lumbosacral motor pools via interlimb projections may exist in SCI participants despite the absence of volitional leg muscle activation. SIGNIFICANCE: Evaluation of sub-clinical, spared pathways within the spinal cord after SCI may provide an improved understanding of both the contributions of different pathways to residual function, and the mechanisms of plasticity and functional motor recovery following rehabilitation..
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Potenciales Evocados Motores , Extremidades/fisiopatología , Traumatismos de la Médula Espinal/fisiopatología , Estimulación de la Médula Espinal/métodos , Estimulación Eléctrica Transcutánea del Nervio/métodos , Adulto , Extremidades/inervación , Femenino , Humanos , Región Lumbosacra/fisiopatología , Masculino , Contracción Muscular , Traumatismos de la Médula Espinal/terapia , Nervio Cubital/fisiopatologíaRESUMEN
For the Ice Giants, atmospheric entry probes provide critical measurements not attainable via remote observations. Including the 2013-2022 NASA Planetary Decadal Survey, there have been at least five comprehensive atmospheric probe engineering design studies performed in recent years by NASA and ESA. International science definition teams have assessed the science requirements, and each recommended similar measurements and payloads to meet science goals with current instrument technology. The probe system concept has matured and converged on general design parameters that indicate the probe would include a 1-meter class aeroshell and have a mass around 350 to 400-kg. Probe battery sizes vary, depending on the duration of a post-release coast phase, and assumptions about heaters and instrument power needs. The various mission concepts demonstrate the need for advanced power and thermal protection system development. The many completed studies show an Ice Giant mission with an in situ probe is feasible and would be welcomed by the international science community.
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AIM: To investigate whether subjective radiologist grading of motility on magnetic resonance enterography (MRE) is as effective as software quantification, and to determine the combination of motility metrics with the strongest association with symptom severity. MATERIALS AND METHODS: One hundred and five Crohn's disease patients (52 male, 53 female, 16-68 years old, mean age 34 years old) recruited from two sites underwent MRE, including a 20 second breath-hold cine motility sequence. Each subject completed a Harvey-Bradshaw Index (HBI) symptom questionnaire. Five features within normally appearing bowel were scored visually by two experienced radiologists, and then quantified using automated analysis software, including (1) mean motility, (2) spatial motility variation, (3) temporal motility variation, (4) area of motile bowel, (5) intestinal distension. Multivariable linear regression derived the combination of features with the highest association with HBI score. RESULTS: The best automated metric combination was temporal variation (p<0.05) plus area of motile bowel (p<0.05), achieving an R2 adjusted value of 0.036. Spatial variation was also associated with symptoms (p<0.05, R2 adjusted = 0.034); however, when visually assessed by radiologists, none of the features had a significant relationship with the HBI score. CONCLUSION: Software quantified temporal and spatial variability in bowel motility are associated with abdominal symptoms in Crohn's disease. Subjective radiologist assessment of bowel motility is insufficient to detect aberrant motility. Automated analysis of motility patterns holds promise as an objective biomarker for aberrant physiology underlying symptoms in enteric disorders.
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Enfermedad de Crohn/diagnóstico por imagen , Motilidad Gastrointestinal/fisiología , Intestino Delgado/diagnóstico por imagen , Imagen por Resonancia Magnética , Adolescente , Adulto , Anciano , Enfermedad de Crohn/fisiopatología , Femenino , Humanos , Interpretación de Imagen Asistida por Computador , Intestino Delgado/fisiopatología , Masculino , Persona de Mediana Edad , Radiólogos , Índice de Severidad de la Enfermedad , Programas Informáticos , Adulto JovenRESUMEN
In this cross-sectional study of 141 Aboriginal Australians aged ≥45 years living in the remote Kimberley region of Western Australia, we explored whether glycated haemoglobin (HbA1c) levels were associated with frailty. Sixty-four participants (45.4%) had a HbA1c level ≥6.5% and 84 participants (59.6%) were frail. A significant trend was observed with regard to HbA1c levels and frailty, with those having HbA1c levels ≥6.5% having the greatest prevalence of frailty (70.3%). In binary logistic regression analyses, having a HbA1c level ≥6.5% was associated with being frail after adjustment for age, sex, and education. This association was attenuated after further adjustment for body mass index (BMI). Poorer glycaemic control is very common and a potential risk factor for frailty in remote-living Aboriginal Australians, and appears to be partly mediated by BMI, a known risk factor for diabetes mellitus. Obesity and diabetes mellitus are potentially important modifiable risk factors for frailty.
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Fragilidad/etnología , Hemoglobina Glucada/análisis , Nativos de Hawái y Otras Islas del Pacífico/estadística & datos numéricos , Australia , Estudios Transversales , Fragilidad/sangre , Humanos , Persona de Mediana Edad , Factores de RiesgoRESUMEN
Temporary and permanent tracheostomies are required in children to manage actual or anticipated long-term ventilatory support, to aid secretion management or to manage fixed upper airway obstruction. Tracheostomies may be required from the first few moments of life, with the majority performed in children < 4 years of age. Although similarities with adult tracheostomies are apparent, there are key differences when managing the routine and emergency care of children with tracheostomies. The National Tracheostomy Safety Project identified the need for structured guidelines to aid multidisciplinary clinical decision making during paediatric tracheostomy emergencies. These guidelines describe the development of a bespoke emergency management algorithm and supporting resources. Our aim is to reduce the frequency, nature and severity of paediatric tracheostomy emergencies through preparation and education of staff, parents, carers and patients.
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Obstrucción de las Vías Aéreas , Servicios Médicos de Urgencia , Pediatría , Traqueostomía , Preescolar , Humanos , Lactante , Recién Nacido , Obstrucción de las Vías Aéreas/terapia , Urgencias Médicas , Servicios Médicos de Urgencia/métodos , Pediatría/métodos , Traqueostomía/métodosRESUMEN
Pontocerebellar hypoplasia type 1 (PCH1) is a major cause of non-5q spinal muscular atrophy (SMA). We screened 128 SMN1-negative SMA patients from Bulgaria for a frequent mutation -p.G31A in EXOSC3, and performed a literature review of all genetically verified PCH1 cases. Homozygous p.G31A/EXOSC3 mutation was identified in 14 Roma patients, representing three fourths of all our SMN1-negative Roma SMA cases. The phenotype of the p.G31A/EXOSC3 homozygotes was compared to the clinical presentation of all reported to date genetically verified PCH1 cases. Signs of antenatal onset of disease present at birth were common in all PCH1 sub-types except in the homozygous p.D132A/EXOSC3 patients. The PCH1sub-types with early death (between ages 1 day and 17 months), seen in patients with p.G31A/EXOSC3 or SLC25A46 mutations have a SMA type 1-like clinical presentation but with global developmental delay, visual and hearing impairment, with or without microcephaly, nystagmus and optic atrophy. Mutations with milder presentation (homozygous p.D132A/EXOSC3 or VRK1) may display additionally signs of upper motor neuron impairment, dystonia or ataxia and die at age between 5 and 18 years. Other EXOSC3 mutations and EXOSC8 cases are intermediate - SMA type 1-like presentation, spasticity (mostly in EXOSC8) and death between 3 months and 5 years. There is no correlation between neurological onset and duration of life. We add marble-like skin and congenital laryngeal stridor as features of PCH1. We show that imaging signs of cerebellar and pontine hypoplasia may be missing early in infancy. EMG signs of anterior horn neuronopathy may be missing in PCH1 patients with SLC25A46 mutations. Thus, there is considerable phenotypic variability in PCH1, with some cases being more SMA-like, than PCH-like. Detailed clinical evaluation and ethnicity background may guide genetic testing and subsequent genetic counseling.
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Atrofias Olivopontocerebelosas/diagnóstico , Atrofias Olivopontocerebelosas/genética , Atrofias Musculares Espinales de la Infancia/genética , Adolescente , Bulgaria , Niño , Preescolar , Complejo Multienzimático de Ribonucleasas del Exosoma/genética , Femenino , Estudios de Asociación Genética , Homocigoto , Humanos , Masculino , Mutación , Atrofias Olivopontocerebelosas/patología , Fenotipo , Proteínas de Unión al ARN/genética , Romaní/genéticaRESUMEN
BACKGROUND AND PURPOSE: Visual rating scales have limited capacities to depict the regional distribution of cerebral white matter hyperintensities (WMH). We present a regional-zonal volumetric analysis alongside a visualization tool to compare and deconstruct visual rating scales. MATERIALS AND METHODS: 3D T1-weighted, T2-weighted spin-echo and FLAIR images were acquired on a 3T system, from 82 elderly participants in a population-based study. Images were automatically segmented for WMH. Lobar boundaries and distance to ventricular surface were used to define white matter regions. Regional-zonal WMH loads were displayed using bullseye plots. Four raters assessed all images applying three scales. Correlations between visual scales and regional WMH as well as inter and intra-rater variability were assessed. A multinomial ordinal regression model was used to predict scores based on regional volumes and global WMH burdens. RESULTS: On average, the bullseye plot depicted a right-left symmetry in the distribution and concentration of damage in the periventricular zone, especially in frontal regions. WMH loads correlated well with the average visual rating scores (e.g. Kendall's tau [Volume, Scheltens]=0.59 CI=[0.53 0.62]). Local correlations allowed comparison of loading patterns between scales and between raters. Regional measurements had more predictive power than global WMH burden (e.g. frontal caps prediction with local features: ICC=0.67 CI=[0.53 0.77], global volume=0.50 CI=[0.32 0.65], intra-rater=0.44 CI=[0.23 0.60]). CONCLUSION: Regional-zonal representation of WMH burden highlights similarities and differences between visual rating scales and raters. The bullseye infographic tool provides a simple visual representation of regional lesion load that can be used for rater calibration and training.
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Leucoaraiosis/diagnóstico por imagen , Leucoaraiosis/patología , Imagen por Resonancia Magnética/métodos , Anciano , Femenino , Humanos , Imagenología Tridimensional , MasculinoAsunto(s)
Hospitales Pediátricos , Seguridad del Paciente , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/prevención & control , Centros de Atención Terciaria , Traqueostomía/efectos adversos , Niño , Humanos , Paquetes de Atención al Paciente , Guías de Práctica Clínica como Asunto , Estudios Retrospectivos , Traqueostomía/métodos , Reino UnidoRESUMEN
The Dzyaloshinskii-Moriya interaction has been shown to stabilise Nèel domain walls in magnetic thin films, allowing high domain wall velocities driven by spin current effects. The interfacial Dzyaloshinskii-Moriya interaction (IDMI) occurs at the interface between ferromagnetic and heavy metal layers with strong spin-orbit coupling, but details of the interaction remain to be understood and the role of proximity induced magnetism (PIM) in the heavy metal is unknown. Here IDMI and PIM are reported in Pt determined as a function of Au and Ir spacer layers in Pt/Co/Au,Ir/Pt. Both interactions are found to be sensitive to sub-nanometre changes in the spacer thickness, correlating over sub-monolayer spacer thicknesses, but not for thicker spacers where IDMI continues to change even after PIM is lost.
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Heavy metal layers, exemplified by Pt, are known to play a significant role in the magnetization behaviour of thin-film ferromagnets by three distinct mechanisms that can each contribute to the reversal process. These include modifying the local magnetization state via an interfacial Dzyaloshinskii-Moriya interaction (IDMI), enhancement of the damping, via d-d hybridisation and spin-pumping across the interface, and the mediation of the magnetization switching, with the flow of current through a system, via the spin-Hall effect. Here we show for a system with weak interfacial DMI (NiFe/Pt) that the measurement of magnetic field-driven magnetization reversal, mediated by domain wall (DW) motion, is dominated by the enhanced intrinsic damping contribution as a function of the Pt capping layer thickness. But, we also show micromagnetically that the IDMI and damping also combine to modify the domain wall velocity behaviour when the damping is larger. It is also noted that Walker breakdown occurs at lower fields and peak DW velocity decreases in the presence of IDMI. These results highlight the significance of the relative contributions of the damping and the IDMI from the heavy metal layer on the magnetization reversal and provide a route to controlling the DW behaviour in nanoscale device structures.
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The separation of spin-up and spin-down conduction channels is fundamental to electronic transport in ferromagnets and essential for spintronic functionality. The spin states available for conduction are defined by the ferromagnetic material, but additional physical factors can affect scattering and modify the spin-dependence of conduction. Here the effect of mesoscopic structuring, arising during the growth of ferromagnetic thin films, on the electronic transport was investigated. Resistivity and anisotropic magnetoresistance were measured in a series of Ni80Fe20 thin films as a function of nominal film thickness from [Formula: see text] up to [Formula: see text]. The observed thickness dependence of the resisivity and magnetic anisotropy of resistivity are interpreted using a model that accounts for the macroscopic structuring from the growth of the films and incorporates a structural dependence of the spin-flip scattering. The model shows good agreement for both the thickness dependence of the resistivity and the reduction of the anisotropic magnetoresistivity. The latter indicating that increasing mixing of the conducting spin channels occurs in ultra-thin films, mainly a consequence of macroscopic structuring of the films.
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BACKGROUND: The clinical use of Magnetic Resonance Imaging (MRI) for investigating gastric motor function in dyspepsia is limited, largely due to protocol complexity, cost and limited availability. In this study, we explore the feasibility of a sub 60-minute protocol using a water challenge to assess gastric emptying, motility and accommodation in a cohort of Ehlers-Danlos Syndrome-Hypermobility type (EDS-HT) patients presenting with dyspepsia. METHODS: Nine EDS-HT patients (mean age 33, range: 26-50 all female) with a history of dyspepsia were recruited together with nine-matched controls. Subjects fasted for 6 hours prior to MRI. A baseline anatomical and motility scan was performed after which the subjects ingested 300 mL water. The anatomical and motility scans were then repeated every 10 minutes to a total of 60 minutes. Gastric emptying time, motility, and accommodation were calculated based on the observations of two observers for each EDS-HT subject and compared to their matched control using paired statistics. KEY RESULTS: Median motility increase following the water challenge was lower in EDS-HT subjects (11%, range: 0%-22%) compared to controls (22%, range: 13%-56%), P=.03. Median gastric emptying time was non-significantly decreased in EDS-HT subjects (12.5 minutes, range: 6-27) compared to controls (20 minutes, range: 7-30), P=.15. Accommodation was non-significantly reduced in EDS-HT subjects (56% increase, range: 32%-78%) compared to healthy controls (67% increase, range: 52%-78%), P=.19. CONCLUSIONS & INFERENCES: This study demonstrates the feasibility of a water challenge MRI protocol to evaluate gastric physiology in the clinical setting. Motility differences between EDS-HT and controls are worthy of further investigation.
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Dispepsia/diagnóstico por imagen , Síndrome de Ehlers-Danlos/complicaciones , Imagen por Resonancia Magnética/métodos , Adulto , Estudios de Cohortes , Dispepsia/etiología , Estudios de Factibilidad , Femenino , Motilidad Gastrointestinal/fisiología , Humanos , Persona de Mediana EdadRESUMEN
Poor health and growth in young dairy calves can have lasting effects on their development and future production. This study benchmarked calf-rearing outcomes in a cohort of Canadian dairy farms, reported these findings back to producers and their veterinarians, and documented the results. A total of 18 Holstein dairy farms were recruited, all in British Columbia. Blood samples were collected from calves aged 1 to 7 d. We estimated serum total protein levels using digital refractometry, and failure of passive transfer (FPT) was defined as values below 5.2 g/dL. We estimated average daily gain (ADG) for preweaned heifers (1 to 70 d old) using heart-girth tape measurements, and analyzed early (≤35 d) and late (>35 d) growth separately. At first assessment, the average farm FPT rate was 16%. Overall, ADG was 0.68 kg/d, with early and late growth rates of 0.51 and 0.90 kg/d, respectively. Following delivery of the benchmark reports, all participants volunteered to undergo a second assessment. The majority (83%) made at least 1 change in their colostrum-management or milk-feeding practices, including increased colostrum at first feeding, reduced time to first colostrum, and increased initial and maximum daily milk allowances. The farms that made these changes experienced improved outcomes. On the 11 farms that made changes to improve colostrum feeding, the rate of FPT declined from 21 ± 10% before benchmarking to 11 ± 10% after making the changes. On the 10 farms that made changes to improve calf growth, ADG improved from 0.66 ± 0.09 kg/d before benchmarking to 0.72 ± 0.08 kg/d after making the management changes. Increases in ADG were greatest in the early milk-feeding period, averaging 0.13 kg/d higher than pre-benchmarking values for calves ≤35 d of age. Benchmarking specific outcomes associated with calf rearing can motivate producer engagement in calf care, leading to improved outcomes for calves on farms that apply relevant management changes.