Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 125
Filtrar
Más filtros

Bases de datos
Tipo del documento
Intervalo de año de publicación
1.
Psychol Res ; 87(2): 519-536, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-35249147

RESUMEN

The rubber hand illusion (RHI) is a perceptual illusion in which one is made to feel that a hand-shaped object is part of their body. This illusion is believed to be the result of the integration of afferent information. However, there has been an increasing amount of evidence that suggests efferent information plays a role in this illusion as well. Previous research has found that individuals who are afflicted by pathological lack of movement experience the RHI more vividly than control participants. Whereas individuals who move their hands more than the general population (i.e. professional pianists) experience the RHI less vividly than control participants. Based upon the available evidence it would seem that muscle activity prior to experiencing the RHI should be associated with how vividly one experiences different indices of the illusion. In the present study we tested this possibility by having participants perform a maximum voluntary muscle contraction task prior to experiencing three variants of the RHI (moving active, moving passive and classic). It was found that electromyographic features known to be indicative of muscle fatigue exhibited a positive association with proprioceptive drift when stimulation was synchronous or visual movement only (with the exception of the passive moving RHI synchronous condition). More work is needed to better characterize the muscular processes associated with experiencing the RHI.


Asunto(s)
Ilusiones , Percepción del Tacto , Humanos , Ilusiones/fisiología , Percepción Visual/fisiología , Imagen Corporal , Mano/fisiología , Propiocepción/fisiología , Músculos , Percepción del Tacto/fisiología
2.
Hum Factors ; 65(8): 1830-1840, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34930044

RESUMEN

OBJECTIVE: This article presents two studies (one simulation and one pilot) that assess a custom computer algorithm designed to predict motion sickness in real-time. BACKGROUND: Virtual reality has a wide range of applications; however, many users experience visually induced motion sickness. Previous research has demonstrated that changes in kinematic (behavioral) parameters are predictive of motion sickness. However, there has not been research demonstrating that these measures can be utilized in real-time applications. METHOD: Two studies were performed to assess an algorithm designed to predict motion sickness in real-time. Study 1 was a simulation study that used data from Smart et al. (2014). Study 2 employed the algorithm on 28 new participants' motion while exposed to virtual motion. RESULTS: Study 1 revealed that the algorithm was able to classify motion sick participants with 100% accuracy. Study 2 revealed that the algorithm could predict if a participant would become motion sick with 57% accuracy. CONCLUSION: The results of the present study suggest that the motion sickness prediction algorithm can predict if an individual will experience motion sickness but needs further refinement to improve performance. APPLICATION: The algorithm could be used for a wide array of VR devices to predict likelihood of motion sickness with enough time to intervene.


Asunto(s)
Mareo por Movimiento , Realidad Virtual , Humanos , Fenómenos Biomecánicos , Simulación por Computador , Algoritmos
3.
J Clin Monit Comput ; 36(2): 325-334, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-33492490

RESUMEN

Electrical impedance tomography (EIT) is used in lung physiology monitoring. There is evidence that EIT is linearly associated with global tidal volume (VT) in clinically healthy patients where no positive end-expiratory pressure (PEEP) is applied. This linearity has not been challenged by altering lung conditions. The aim of this study was to determine the effect of PEEP on VT estimation, using EIT technology and spirometry, and observe the stability of the relationship under changing lung conditions. Twelve male castrated cattle (Steer), mean age 7.8 months (SD ± 1.7) were premedicated with xylazine followed by anaesthesia induction with ketamine and maintenance with halothane in oxygen via an endotracheal tube. An EIT belt was applied around the thorax at the level of the fifth intercostal space. Volume controlled ventilation was used. PEEP was increased in a stepwise manner from 0 to 5, 10 and 15 cmH2O. At each PEEP, the VT was increased stepwise from 5 to 10 and 15 mL kg-1. After a minute of stabilisation, total impedance change (VTEIT), using EIT and VT measured by a spirometer connected to a flow-partitioning device (VTSpiro) was recorded for the following minute before changing ventilator settings. Data was analysed using linear regression and multi variable analysis. There was a linear relationship between VTEIT and VTSpiro at all levels of PEEP with an R2 of 0.71, 0.68, 0.63 and 0.63 at 0, 5, 10 and 15 cmH2O, respectively. The variance in VTEIT was best described by peak inspiratory pressure (PIP) and PEEP (adjusted R2 0.82) while variance in VTSpiro was best described by PIP and airway deadspace (adjusted R2 0.76). The relationship between VTEIT and VTSpiro remains linear with changes in tidal volume, and stable across altered lung conditions. This may have application for monitoring and assessment in vivo.


Asunto(s)
Respiración con Presión Positiva , Tomografía , Animales , Bovinos , Impedancia Eléctrica , Humanos , Masculino , Respiración con Presión Positiva/métodos , Volumen de Ventilación Pulmonar , Tomografía/métodos , Tomografía Computarizada por Rayos X
4.
Perception ; 50(1): 88-96, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33287660

RESUMEN

The rubber hand illusion (RHI) is a perceptual illusion in which one experiences an object as part of their body when synchronous visuo-tactile stimulation is applied to one's hand and the object. There are a variety of factors that can impact the occurrence of the RHI. In the present study, we demonstrate that experimentally induced peripheral ischemia can impact the RHI, namely it can result in larger alterations to the perceived position of one's hand. This study suggests that alterations to the cardiovascular system may be a source of individual differences in the RHI literature. Future studies with samples of individuals with cardiovascular pathology are recommended.


Asunto(s)
Ilusiones , Percepción del Tacto , Humanos , Isquemia , Propiocepción , Percepción Visual
5.
Perception ; 50(11): 966-975, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34779666

RESUMEN

The Rubber Foot Illusion (RFI) is an illusion in which one is made to feel that a model foot is their own through synchronous visuo-tactile stimulation. Previous research suggests that the conditions the RFI can be elicited under are similar to those of the Rubber Hand Illusion (RHI). However, it was unknown if the RFI could be elicited by synchronous movement of a participant's foot and a model foot. To examine this, we developed the Moving Rubber Foot Illusion (mRFI) and compared participants' experience of it to the RFI. The results of this study suggests that the RFI can be elicited through synchronous movement, and results in more proprioceptive drift than a static variant of the RFI. More work is needed to better understand the mechanisms underlying the mRFI.


Asunto(s)
Ilusiones , Percepción del Tacto , Imagen Corporal , Femenino , Mano , Humanos , Propiocepción , Estudiantes , Universidades , Percepción Visual
6.
Cogn Emot ; 35(2): 214-224, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-32924777

RESUMEN

Visual search studies have shown that threatening facial expressions are more efficiently detected among a crowd of distractor faces than nonthreatening expressions, known as the anger superiority effect (ASE). However, the opposite finding has also been documented. The present study investigated the ASE in the visual periphery with a visual crowding task. In the study, the target face either appeared alone (uncrowded condition) or was crowded by four neutral or emotional faces (crowded condition). Participants were instructed to determine whether the target face was happy or angry. Experiment 1 showed an ASE when crowded by neutral faces. Intriguingly, this superiority vanished when the target face was crowded by emotional faces that had a different expression from the target as well as when the target face was presented alone. Experiment 2 replicated this result in an independent sample of East Asians (vs. Caucasians in Experiment 1) and thus demonstrated the robustness and cross-cultural consistency of our findings. Together, these results suggest that the ASE in the visual periphery is contingent on task demands induced by visual crowding.


Asunto(s)
Ira , Expresión Facial , Aglomeración , Emociones , Felicidad , Humanos
7.
Phys Rev Lett ; 124(24): 244801, 2020 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-32639812

RESUMEN

Continuous-wave photoinjectors operating at high accelerating gradients promise to revolutionize many areas of science and applications. They can establish the basis for a new generation of monochromatic x-ray free electron lasers, high-brightness hadron beams, or a new generation of microchip production. In this Letter we report on the record-performing superconducting rf electron gun with CsK_{2}Sb photocathode. The gun is generating high charge electron bunches (up to 10 nC/bunch) and low transverse emittances, while operating for months with a single photocathode. This achievement opens a new era in generating high-power beams with a very high average brightness.

8.
Surgeon ; 16(5): 283-291, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29526658

RESUMEN

OBJECTIVE: To establish the long term outcomes of risk stratified management of differentiated thyroid cancer (DTC). BACKGROUND: Guidelines for management of DTC lack a strong evidence base and expose patients to overtreatment. This prospective study of patients diagnosed with DTC between 1977 and 2012 describes the long term outcomes of a conservative risk stratified (AMES) management policy. METHODS: Outcomes were analysed around patient and tumour characteristics, primary intervention (surgery ± radioiodine (RAI)), in terms of mortality, recurrence and reintervention. RESULTS: Median follow-up in 348 patients was 14 years: mean age 48 (range 10-91) years, 257 (73.9%) female, 222 (68.3%) papillary cancer, tumour size 3.4 ± 2.0 cm (mean ± SD). 89 (25.6%) AMES high risk, 116 (33.3%) TNM stage III/IV and 16 (4.6%) had distant metastases. Primary surgery comprised lobectomy in 189 (54.3%): 11 (5.8%) patients had subsequent completion total thyroidectomy with cancer present in five. Primary nodal surgery was performed in 142 (40.8%) patients. 35 (13.5%) low and 43 (48.3%) high risk patients received RAI following initial surgery. Overall disease specific survival (DSS) was 92.1% at 10 years and 90.7% at 20 years. DSS at 20 years was 99.2% in low risk cases. AMES risk scoring predicted both survival and recurrence. Patients receiving RAI and AMES high risk were significantly associated with increased risk of death and recurrence. CONCLUSIONS: Routine total thyroidectomy and RAI are not justifiable for low risk DTC. Treatment should be tailored to risk and AMES risk stratification remains a simple reliable clinical tool.


Asunto(s)
Adenocarcinoma/terapia , Neoplasias de la Tiroides/terapia , Adenocarcinoma/patología , Adenocarcinoma/radioterapia , Adenocarcinoma/cirugía , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Antineoplásicos/administración & dosificación , Niño , Femenino , Humanos , Radioisótopos de Yodo/administración & dosificación , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Medición de Riesgo , Neoplasias de la Tiroides/patología , Neoplasias de la Tiroides/radioterapia , Neoplasias de la Tiroides/cirugía , Tiroidectomía , Adulto Joven
9.
Acta Psychiatr Scand ; 135(5): 409-418, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28374419

RESUMEN

OBJECTIVE: Establish whether inflammatory biomarkers-serum amyloid A (SAA), C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α)-are related to key symptoms of depression, including anxiety and fatigue, in a cross-sectional, out-patient setting to identify biomarkers that reflect psychiatric symptomatology in a naturalistic, real-life population. METHODS: We measured SAA, CRP, IL-6, and TNF-α in plasma samples from 89 adult psychiatric out-patients by multiplex, high-sensitivity electrochemiluminescent assays. Psychiatric symptoms were evaluated using the Hamilton Depression Rating Scale (HAMD-17), the Patient Health Questionnaire (PHQ-9), and the Center for Epidemiological Studies Depression Scale (CES-D). RESULTS: Plasma SAA was most robustly associated with depressive symptoms across diagnostic boundaries in this cohort of out-patients. Elevated SAA was significantly associated with higher total scores on the HAMD-17 scale and correlated with multiple scale items that rated symptoms of fatigue and depressed mood, but not with anxiety-related items. CONCLUSIONS: SAA might constitute a cross-diagnostic marker indicative of depressed mood and fatigue in a naturalistic patient setting. Because SAA activates Toll-like receptors 2 and 4, present on macrophages and glial cells, its association with depression severity could also implicate this inflammatory mediator in the pathogenesis of mood disorders.


Asunto(s)
Depresión/metabolismo , Fatiga/metabolismo , Proteína Amiloide A Sérica/metabolismo , Adulto , Anciano , Proteína C-Reactiva/metabolismo , Estudios Transversales , Femenino , Humanos , Interleucina-6/sangre , Masculino , Persona de Mediana Edad , Escalas de Valoración Psiquiátrica , Factor de Necrosis Tumoral alfa/sangre , Adulto Joven
10.
BJOG ; 124(9): 1394-1401, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28102931

RESUMEN

OBJECTIVE: To determine whether human papillomavirus (HPV) immunisation has affected the prevalence of HPV genotypes and colposcopic features of cervical intraepithelial neoplasia (CIN) in young women referred for colposcopy. DESIGN: A two-centre observational study including vaccinated and unvaccinated women. SETTING: Colposcopy clinics serving two health regions in Scotland, UK. POPULATION: A total of 361 women aged 20-25 years attending colposcopy following an abnormal cervical cytology result at routine cervical screening. METHODS: Cervical samples were obtained from women for HPV DNA genotyping and mRNA E6/E7 expression of HPV 16, 18, 31, 33, and 45. Demographic data, cytology, and histology results and colposcopic features were recorded. Chi-square analysis was conducted to identify associations between vaccine status, HPV genotypes, and colposcopic features. MAIN OUTCOME MEASURES: Colposcopic features, HPV genotypes, mRNA expression, and cervical histology. RESULTS: The prevalence of HPV 16 was significantly lower in the vaccinated group (8.6%) compared with the unvaccinated group (46.7%) (P = 0.001). The number of cases of CIN2+ was significantly lower in women who had been vaccinated (P = 0.006). The HPV vaccine did not have a statistically significant effect on commonly recognised colposcopic features, but there was a slight reduction in the positive predictive value (PPV) of colposcopy for CIN2+, from 74% (unvaccinated) to 66.7% (vaccinated). CONCLUSIONS: In this group of young women with abnormal cytology referred to colposcopy, HPV vaccination via a catch-up programme reduced the prevalence of CIN2+ and HPV 16 infection. The reduced PPV of colposcopy for the detection of CIN2+ in women who have been vaccinated is at the lower acceptable level of the UK national cervical screening programme guidelines. TWEETABLE ABSTRACT: Reduction of hrHPV positivity and CIN in immunised women consistent with lower PPV of colposcopy for CIN2+.


Asunto(s)
Colposcopía , Papillomaviridae/genética , Infecciones por Papillomavirus/virología , Vacunas contra Papillomavirus , Displasia del Cuello del Útero/diagnóstico por imagen , Neoplasias del Cuello Uterino/diagnóstico por imagen , Adulto , Estudios Transversales , Femenino , Genotipo , Humanos , Papillomaviridae/aislamiento & purificación , Infecciones por Papillomavirus/complicaciones , Infecciones por Papillomavirus/diagnóstico , Infecciones por Papillomavirus/prevención & control , Escocia , Neoplasias del Cuello Uterino/patología , Neoplasias del Cuello Uterino/prevención & control , Neoplasias del Cuello Uterino/virología , Displasia del Cuello del Útero/patología , Displasia del Cuello del Útero/prevención & control , Displasia del Cuello del Útero/virología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA