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1.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 36(5): 763-768, 2019 Oct 25.
Artigo em Zh | MEDLINE | ID: mdl-31631624

RESUMO

Focus on the inconsistency of the shape, location and size of brain glioma, a dual-channel 3-dimensional (3D) densely connected network is proposed to automatically segment brain glioma tumor on magnetic resonance images. Our method is based on a 3D convolutional neural network frame, and two convolution kernel sizes are adopted in each channel to extract multi-scale features in different scales of receptive fields. Then we construct two densely connected blocks in each pathway for feature learning and transmission. Finally, the concatenation of two pathway features was sent to classification layer to classify central region voxels to segment brain tumor automatically. We train and test our model on open brain tumor segmentation challenge dataset, and we also compared our results with other models. Experimental results show that our algorithm can segment different tumor lesions more accurately. It has important application value in the clinical diagnosis and treatment of brain tumor diseases.


Assuntos
Neoplasias Encefálicas/diagnóstico por imagem , Glioma/diagnóstico por imagem , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Humanos , Redes Neurais de Computação
2.
Dev Sci ; 21(5): e12631, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29143475

RESUMO

Pediatric reading disorder (RD) is associated with an increased risk of anxiety symptoms, yet understudied are the neurobiological factors that might underlie anxiety in children with RD. Given the role of the amygdala in anxiety, we assessed resting state functional connectivity of amygdalar subregions in children with RD to identify functional correlates of anxiety and reading impairment. We collected resting state functional MRI data from 22 children with RD and 21 typically developing (TD) children, ages 7 to 13 years. We assessed group differences in resting state functional connectivity (RSFC) from amygdalar subregions. Associations of amygdalar RSFC and volume with reading impairment, reading fluency scores, and anxiety symptoms were explored. Relative to TD children, those with RD showed increased RSFC from amygdalar nuclei to medial prefrontal cortex. Across all subjects, RSFC from right centromedial amygdala to left medial prefrontal cortex positively predicted both reading impairment and self-reported anxiety, and anxiety mediated the relationship between RSFC and reading impairment. These findings are consistent with amygdalar functional abnormalities in pediatric anxiety disorders, suggesting a common neurobiological mechanism underlying anxiety and reading impairment in children. Thus, aberrant patterns of RSFC from amygdalar subregions may serve as potential targets for the treatment of anxiety symptoms that typically co-occur with RD. Our dimensional approach to studying anxiety in RD revealed how amygdalar connectivity underlies anxiety and reading impairment across a continuum from normal to abnormal.


Assuntos
Tonsila do Cerebelo/fisiologia , Transtornos de Ansiedade/fisiopatologia , Ansiedade/fisiopatologia , Dislexia/fisiopatologia , Córtex Pré-Frontal/fisiologia , Adolescente , Mapeamento Encefálico , Criança , Desenvolvimento Infantil/fisiologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino
3.
Carbohydr Polym ; 256: 117575, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33483070

RESUMO

Chitosan-modified zinc hydroxystannate (ZHS-CS) was synthesized using the cations of the biomaterial chitosan (CS) and ion replacement strategy. A ZHS-CS and reduced graphene oxide (rGO) hybrid flame retardant (ZHS-CS/rGO) was synthesized for use in flexible poly (vinyl chloride) (PVC). Scanning electron microscopy images indicated that ZHS-CS and rGO were evenly dispersed in ZHS-CS/rGO without agglomeration. Fourier transform infrared spectroscopy results showed that rGO was fully reduced. The flame-retardant and mechanical properties of PVC composites were investigated using the limiting oxygen index (LOI), a cone calorimeter, and mechanical equipment. By replacing one-fifth of the zinc ions in ZHS by chitosan cations to obtain Sn-4Zn-1CS/rGO, the ZHS-CS/rGO was found to improve PVC composite performance. The total heat release and total smoke release of PVC/Sn-4Zn-1CS/rGO were reduced by 24.2 and 40.0 %, respectively, from those of pure PVC.


Assuntos
Quitosana/química , Grafite/síntese química , Cloreto de Polivinila/química , Compostos de Estanho/química , Zinco/química , Materiais Biocompatíveis/química , Retardadores de Chama , Grafite/química , Microscopia Eletrônica de Varredura , Óxidos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Estresse Mecânico , Temperatura , Resistência à Tração , Compostos de Zinco , Óxido de Zinco
4.
Artigo em Inglês | MEDLINE | ID: mdl-30846367

RESUMO

BACKGROUND: Bulimia nervosa (BN) is associated with functional abnormalities in frontostriatal and frontolimbic circuits. Although structural alterations in the frontal portions of these circuits have been observed, this is the first study of subcortical surface morphometry and the largest study of subcortical volume in BN. METHODS: Anatomical magnetic resonance scans were acquired from 62 female participants with full and subthreshold BN (mean age ± SD, 18.7 ± 4.0 years) and 65 group-matched healthy control participants (mean age ± SD, 19.3 ± 5.7 years). General linear models were used to compare groups and assess the significance of group-by-age interactions on the shape and total volume of 15 subcortical structures (p < .05, familywise error corrected). Associations with illness severity and duration were assessed in the BN group. RESULTS: Subcortical volumes did not differ across groups, but vertexwise analyses revealed inward shape deformations on the anterior surface of the pallidum in BN relative to control participants that were associated with binge-eating frequency and illness duration. Inward deformations on the ventrolateral thalamus and dorsal amygdala were more pronounced with advancing age in the BN group, and inward deformations on the caudate, putamen, and amygdala were associated with self-induced vomiting frequency. CONCLUSIONS: Our findings point to localized deformations on the surface of subcortical structures in areas that comprise both reward and cognitive control circuits. These deformations were more pronounced among older BN participants and among those with the most severe symptoms. Such precise localization of alterations in subcortical morphometry may ultimately aid in efforts to identify markers of risk and BN persistence.


Assuntos
Tonsila do Cerebelo/patologia , Gânglios da Base/patologia , Transtorno da Compulsão Alimentar/patologia , Bulimia Nervosa/patologia , Tálamo/patologia , Adolescente , Adulto , Tonsila do Cerebelo/diagnóstico por imagem , Gânglios da Base/diagnóstico por imagem , Transtorno da Compulsão Alimentar/diagnóstico por imagem , Transtorno da Compulsão Alimentar/fisiopatologia , Bulimia Nervosa/diagnóstico por imagem , Bulimia Nervosa/fisiopatologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Tálamo/diagnóstico por imagem , Adulto Jovem
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