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  1 / 11210 MEDLINE  
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[PMID]:29199498
[Au] Autor:Strbac V; Pierce DM; Vander Sloten J; Famaey N
[Ad] Endereço:a Biomechanics Section, Department of Mechanical Engineering , KULeuven , Heverlee , Belgium .
[Ti] Título:GPGPU-based explicit finite element computations for applications in biomechanics: the performance of material models, element technologies, and hardware generations.
[So] Source:Comput Methods Biomech Biomed Engin;20(16):1643-1657, 2017 Dec.
[Is] ISSN:1476-8259
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Finite element (FE) simulations are increasingly valuable in assessing and improving the performance of biomedical devices and procedures. Due to high computational demands such simulations may become difficult or even infeasible, especially when considering nearly incompressible and anisotropic material models prevalent in analyses of soft tissues. Implementations of GPGPU-based explicit FEs predominantly cover isotropic materials, e.g. the neo-Hookean model. To elucidate the computational expense of anisotropic materials, we implement the Gasser-Ogden-Holzapfel dispersed, fiber-reinforced model and compare solution times against the neo-Hookean model. Implementations of GPGPU-based explicit FEs conventionally rely on single-point (under) integration. To elucidate the expense of full and selective-reduced integration (more reliable) we implement both and compare corresponding solution times against those generated using underintegration. To better understand the advancement of hardware, we compare results generated using representative Nvidia GPGPUs from three recent generations: Fermi (C2075), Kepler (K20c), and Maxwell (GTX980). We explore scaling by solving the same boundary value problem (an extension-inflation test on a segment of human aorta) with progressively larger FE meshes. Our results demonstrate substantial improvements in simulation speeds relative to two benchmark FE codes (up to 300[Formula: see text] while maintaining accuracy), and thus open many avenues to novel applications in biomechanics and medicine.
[Mh] Termos MeSH primário: Gráficos por Computador
Computadores
Análise de Elementos Finitos
[Mh] Termos MeSH secundário: Túnica Adventícia/fisiologia
Anisotropia
Aorta Abdominal/fisiologia
Fenômenos Biomecânicos
Simulação por Computador
Seres Humanos
Reprodutibilidade dos Testes
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180309
[Lr] Data última revisão:
180309
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171205
[St] Status:MEDLINE
[do] DOI:10.1080/10255842.2017.1404586


  2 / 11210 MEDLINE  
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[PMID]:28450434
[Au] Autor:Li X; Gao J; Wang M; Zheng J; Li Y; Hui ES; Wan M; Yang J
[Ad] Endereço:From the Department of Radiology (X.L., J.G., M. Wang, Y.L., J.Y.).
[Ti] Título:Characterization of Extensive Microstructural Variations Associated with Punctate White Matter Lesions in Preterm Neonates.
[So] Source:AJNR Am J Neuroradiol;38(6):1228-1234, 2017 Jun.
[Is] ISSN:1936-959X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:BACKGROUND AND PURPOSE: Punctate white matter lesions are common in preterm neonates. Neurodevelopmental outcomes of the neonates are related to the degree of extension. This study aimed to characterize the extent of microstructural variations for different punctate white matter lesion grades. MATERIALS AND METHODS: Preterm neonates with punctate white matter lesions were divided into 3 grades (from mild to severe: grades I-III). DTI-derived fractional anisotropy, axial diffusivity, and radial diffusivity between patients with punctate white matter lesions and controls were compared with Tract-Based Spatial Statistics and tract-quantification methods. RESULTS: Thirty-three preterm neonates with punctate white matter lesions and 33 matched controls were enrolled. There were 15, 9, and 9 patients, respectively, in grades I, II, and III. Punctate white matter lesions were mainly located in white matter adjacent to the lateral ventricles, especially regions lateral to the trigone, posterior horns, and centrum semiovale and/or corona radiata. Extensive microstructural changes were observed in neonates with grade III punctate white matter lesions, while no significant changes in DTI metrics were found for grades I and II. A pattern of increased axial diffusivity, increased radial diffusivity, and reduced/unchanged fractional anisotropy was found in regions adjacent to punctate white matter lesion sites seen on T1WI and T2WI. Unchanged axial diffusivity, increased radial diffusivity, and reduced/unchanged fractional anisotropy were observed in regions distant from punctate white matter lesion sites. CONCLUSIONS: White matter microstructural variations were different across punctate white matter lesion grades. Extensive change patterns varied according to the distance to the lesion sites in neonates with severe punctate white matter lesions. These findings may help in determining the outcomes of punctate white matter lesions and selecting treatment strategies.
[Mh] Termos MeSH primário: Recém-Nascido Prematuro
Substância Branca/ultraestrutura
[Mh] Termos MeSH secundário: Anisotropia
Ventrículos Cerebrais/diagnóstico por imagem
Ventrículos Cerebrais/patologia
Ventrículos Cerebrais/ultraestrutura
Corpo Caloso/diagnóstico por imagem
Corpo Caloso/patologia
Corpo Caloso/ultraestrutura
Estudos Transversais
Imagem de Tensor de Difusão
Feminino
Seres Humanos
Recém-Nascido
Masculino
Tratos Piramidais/diagnóstico por imagem
Tratos Piramidais/patologia
Tratos Piramidais/ultraestrutura
Substância Branca/diagnóstico por imagem
Substância Branca/patologia
[Pt] Tipo de publicação:JOURNAL ARTICLE; OBSERVATIONAL STUDY
[Em] Mês de entrada:1803
[Cu] Atualização por classe:180302
[Lr] Data última revisão:
180302
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170429
[St] Status:MEDLINE
[do] DOI:10.3174/ajnr.A5226


  3 / 11210 MEDLINE  
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[PMID]:29390334
[Au] Autor:Lee HD; Chang MC
[Ad] Endereço:Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University, Namku, Daegu, Republic of Korea.
[Ti] Título:Degeneration of the corticofugal tract from the secondary motor area in a Parkinson's disease patient with limb-kinetic apraxia: A case report.
[So] Source:Medicine (Baltimore);96(50):e9195, 2017 Dec.
[Is] ISSN:1536-5964
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:RATIONALE: In this case report, we describe a Parkinson's disease (PD) patient with limb-kinetic apraxia (LKA) in whom degeneration of the corticofugal tract (CFT) from the supplementary motor area (SMA) was observed in diffusion tensor tractography (DTT). PATIENT CONCERNS: A 63-year-old woman presented with a loss of dexterity in both upper extremities, which indicated LKA, and typical PD-related symptoms, including a gait disturbance with a short step, resting tremor in both upper extremities, and rigidity, and these symptoms had been present for 2 years. The F-florinated-N-3-fluoropropyl-2-ß-carboxymethoxy-3-ß-(4-lodophenyl) nortropane positron emission tomography scanning findings were consistent with PD. Based on the clinical symptoms and imaging findings, we diagnosed the patient with PD. In a coin-rotation test that was used to evaluate the severity of the LKA, the patient's results significantly decreased compared to the results of the normal controls. DIAGNOSES: The DTT showed that the CFTs from the SMAs in both hemispheres were partially torn and thinned. The fractional anisotropy values and CFT volumes in both SMAs were >2 standard deviations lower than those of the normal controls. INTERVENTIONS: The patient was treated with an initial dose of 150/37.5 mg/day of levodopa/benserazide, and the dose was gradually increased to 400/100 mg/day. OUTCOMES: After treatment, although the bradykinesia, rigidity, and resting tremor of the patient significantly decreased, the dexterity of the patient's hands did not improve. LESSONS: These observations indicated degeneration of the CFTs from the SMAs in both hemispheres in the patient. This degeneration might have, at least in part, contributed to the patient's LKA. The results of this study suggest that CFT degeneration could be one of the pathological mechanisms underlying LKA in patients with PD.
[Mh] Termos MeSH primário: Córtex Motor/patologia
Doença de Parkinson/patologia
[Mh] Termos MeSH secundário: Anisotropia
Antiparkinsonianos/uso terapêutico
Benserazida/uso terapêutico
Imagem de Tensor de Difusão
Combinação de Medicamentos
Feminino
Seres Humanos
Levodopa/uso terapêutico
Meia-Idade
Córtex Motor/diagnóstico por imagem
Rigidez Muscular/diagnóstico por imagem
Rigidez Muscular/tratamento farmacológico
Rigidez Muscular/patologia
Atrofia Muscular Espinal/diagnóstico por imagem
Atrofia Muscular Espinal/tratamento farmacológico
Atrofia Muscular Espinal/patologia
Doença de Parkinson/diagnóstico por imagem
Doença de Parkinson/tratamento farmacológico
Tomografia por Emissão de Pósitrons
Tremor/diagnóstico por imagem
Tremor/tratamento farmacológico
Tremor/patologia
[Pt] Tipo de publicação:CASE REPORTS; JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Antiparkinson Agents); 0 (Drug Combinations); 0 (benserazide, levodopa drug combination); 46627O600J (Levodopa); 762OS3ZEJU (Benserazide)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180301
[Lr] Data última revisão:
180301
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:180203
[St] Status:MEDLINE
[do] DOI:10.1097/MD.0000000000009195


  4 / 11210 MEDLINE  
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[PMID]:29227151
[Au] Autor:Yaparpalvi R; Garg MK; Shen J; Bodner WR; Mynampati DK; Gafar A; Kuo HC; Basavatia AK; Ohri N; Hong LX; Kalnicki S; Tome WA
[Ad] Endereço:Department of Radiation Oncology, Montefiore Medical Center and the Albert Einstein College of Medicine , Bronx, NY , USA.
[Ti] Título:Evaluating which plan quality metrics are appropriate for use in lung SBRT.
[So] Source:Br J Radiol;91(1083):20170393, 2018 Feb.
[Is] ISSN:1748-880X
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:OBJECTIVE: Several dose metrics in the categories-homogeneity, coverage, conformity and gradient have been proposed in literature for evaluating treatment plan quality. In this study, we applied these metrics to characterize and identify the plan quality metrics that would merit plan quality assessment in lung stereotactic body radiation therapy (SBRT) dose distributions. METHODS: Treatment plans of 90 lung SBRT patients, comprising 91 targets, treated in our institution were retrospectively reviewed. Dose calculations were performed using anisotropic analytical algorithm (AAA) with heterogeneity correction. A literature review on published plan quality metrics in the categories-coverage, homogeneity, conformity and gradient was performed. For each patient, using dose-volume histogram data, plan quality metric values were quantified and analysed. RESULTS: For the study, the radiation therapy oncology group (RTOG) defined plan quality metrics were: coverage (0.90 ± 0.08); homogeneity (1.27 ± 0.07); conformity (1.03 ± 0.07) and gradient (4.40 ± 0.80). Geometric conformity strongly correlated with conformity index (p < 0.0001). Gradient measures strongly correlated with target volume (p < 0.0001). The RTOG lung SBRT protocol advocated conformity guidelines for prescribed dose in all categories were met in ≥94% of cases. The proportion of total lung volume receiving doses of 20 Gy and 5 Gy (V and V ) were mean 4.8% (±3.2) and 16.4% (±9.2), respectively. CONCLUSION: Based on our study analyses, we recommend the following metrics as appropriate surrogates for establishing SBRT lung plan quality guidelines-coverage % (ICRU 62), conformity (CN or CI ) and gradient (R ). Furthermore, we strongly recommend that RTOG lung SBRT protocols adopt either CN or CI in place of prescription isodose to target volume ratio for conformity index evaluation. Advances in knowledge: Our study metrics are valuable tools for establishing lung SBRT plan quality guidelines.
[Mh] Termos MeSH primário: Neoplasias Pulmonares/radioterapia
Garantia da Qualidade dos Cuidados de Saúde
Radiocirurgia/métodos
Planejamento da Radioterapia Assistida por Computador
Tomografia Computadorizada por Raios X
[Mh] Termos MeSH secundário: Idoso
Idoso de 80 Anos ou mais
Algoritmos
Anisotropia
Feminino
Seres Humanos
Masculino
Meia-Idade
Dosagem Radioterapêutica
Estudos Retrospectivos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180226
[Lr] Data última revisão:
180226
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:171212
[St] Status:MEDLINE
[do] DOI:10.1259/bjr.20170393


  5 / 11210 MEDLINE  
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[PMID]:29227148
[Au] Autor:Yin P; Liu Y; Xiong H; Han Y; Sah SK; Zeng C; Wang J; Li Y
[Ad] Endereço:1 Department of Radiology, The First Affiliated Hospital of Chongqing Medical University , Chongqing , China.
[Ti] Título:Structural abnormalities and altered regional brain activity in multiple sclerosis with simple spinal cord involvement.
[So] Source:Br J Radiol;91(1083):20150777, 2018 Feb.
[Is] ISSN:1748-880X
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:OBJECTIVE: To assess the changes of the structural and functional abnormalities in multiple sclerosis with simple spinal cord involvement (MS-SSCI) by using resting-state functional MRI (RS-fMRI), voxel based morphology (VBM) and diffusion tensor tractography. METHODS: The amplitude of low-frequency fluctuation (ALFF) of 22 patients with MS-SSCI and 22 healthy controls (HCs) matched for age, gender and education were compared by using RS-fMRI. We also compared the volume, fractional anisotropy (FA) and apparent diffusion coefficient of the brain regions in baseline brain activity by using VBM and diffusion tensor imaging. The relationships between the expanded disability states scale (EDSS) scores, changed parameters of structure and function were further explored. RESULTS: (1) Compared with HCs, the ALFF of the bilateral hippocampus and right middle temporal gyrus in MS-SSCI decreased significantly. However, patients exhibited increased ALFF in the left middle frontal gyrus, left posterior cingulate gyrus and right middle occipital gyrus ( two-sample t-test, after AlphaSim correction, p < 0.01, voxel size > 40). The volume of right middle frontal gyrus reduced significantly (p < 0.01). The FA and ADC of right hippocampus, the FA of left hippocampus and right middle temporal gyrus were significantly different. (2) A significant correlation between EDSS scores and ALFF was noted only in the left posterior cingulate gyrus. CONCLUSION: Our results detected structural and functional abnormalities in MS-SSCI and functional parameters were associated with clinical abnormalities. Multimodal imaging plays an important role in detecting structural and functional abnormalities in MS-SSCI. Advances in knowledge: This is the first time to apply RS-fMRI, VBM and diffusion tensor tractography to study the structural and functional abnormalities in MS-SSCI, and to explore its correlation with EDSS score.
[Mh] Termos MeSH primário: Mapeamento Encefálico/métodos
Encéfalo/diagnóstico por imagem
Encéfalo/patologia
Imagem de Tensor de Difusão/métodos
Imagem por Ressonância Magnética/métodos
Esclerose Múltipla/diagnóstico por imagem
Esclerose Múltipla/patologia
Medula Espinal/diagnóstico por imagem
Medula Espinal/patologia
[Mh] Termos MeSH secundário: Adulto
Anisotropia
Estudos de Casos e Controles
Feminino
Seres Humanos
Masculino
Meia-Idade
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180226
[Lr] Data última revisão:
180226
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:171212
[St] Status:MEDLINE
[do] DOI:10.1259/bjr.20150777


  6 / 11210 MEDLINE  
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[PMID]:28470928
[Au] Autor:Ganzola R; Nickson T; Bastin ME; Giles S; Macdonald A; Sussmann J; McIntosh AM; Whalley HC; Duchesne S
[Ad] Endereço:Institut universitaire en santé mentale de Québec, Québec City, Québec, Canada.
[Ti] Título:Longitudinal differences in white matter integrity in youth at high familial risk for bipolar disorder.
[So] Source:Bipolar Disord;19(3):158-167, 2017 May.
[Is] ISSN:1399-5618
[Cp] País de publicação:Denmark
[La] Idioma:eng
[Ab] Resumo:OBJECTIVES: Previous neuroimaging studies have reported abnormalities in white matter (WM) pathways in subjects at high familial risk of mood disorders. In the current study, we examined the trajectory of these abnormalities during the early stages of illness development using longitudinal diffusion tensor imaging (DTI) data. METHODS: Subjects (16-28 years old) were recruited in the Scottish Bipolar Family Study, a prospective longitudinal study that has examined individuals at familial risk of mood disorder on three occasions, 2 years apart. The current study concerns imaging data from the first and second assessments. We analysed DTI data for 43 controls and 69 high-risk individuals who were further subdivided into a group of 53 high-risk subjects who remained well (high-risk well) and 16 who met diagnostic criteria for major depressive disorder (high-risk MDD) at follow-up. Longitudinal differences in fractional anisotropy (FA) between groups based on diagnostic status were investigated using the tract-based spatial statistics technique (TBSS). RESULTS: We found a significant reduction in FA (P <.05) across widespread brain regions over 2 years in all three groups. The trajectory of FA reduction did not differ significantly between groups. CONCLUSIONS: These results suggest that there are similar trajectories of FA reductions for controls and high-risk young adults, despite high-risk individuals being at a disadvantaged starting point considering their reduced WM integrity detected at baseline in previous studies. Difference in WM integrity between high-risk individuals and controls could therefore occur in earlier childhood and be a necessary but not sufficient condition to develop future mood disorders.
[Mh] Termos MeSH primário: Transtorno Bipolar
Substância Branca/diagnóstico por imagem
[Mh] Termos MeSH secundário: Adolescente
Adulto
Anisotropia
Transtorno Bipolar/diagnóstico
Transtorno Bipolar/epidemiologia
Transtorno Depressivo Maior/diagnóstico
Transtorno Depressivo Maior/epidemiologia
Imagem de Tensor de Difusão/métodos
Feminino
Seres Humanos
Estudos Longitudinais
Masculino
Anamnese/métodos
Neuroimagem/métodos
Estudos Prospectivos
Medição de Risco
Fatores de Risco
Escócia/epidemiologia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180222
[Lr] Data última revisão:
180222
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170505
[St] Status:MEDLINE
[do] DOI:10.1111/bdi.12489


  7 / 11210 MEDLINE  
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[PMID]:29297648
[Au] Autor:Kulesh AA; Drobakha VE; Nekrasova IV; Kuklina EM; Shestakov VV
[Ti] Título:Neuroinflammatory, Neurodegenerative and Structural Brain Biomarkers of the Main Types of Post-Stroke Cognitive Impairment in Acute Period of Ischemic Stroke.
[So] Source:Vestn Ross Akad Med Nauk;71(4):304-12, 2016.
[Is] ISSN:0869-6047
[Cp] País de publicação:Russia (Federation)
[La] Idioma:eng
[Ab] Resumo:Background: Post-stroke cognitive impairment is a clinically heterogeneous condition, some types of which cannot be fully differentiated neuropsychologically that necessitates the active search for biomarkers. Aims: Analyze parameters of neuroinflammation and neurodegeneration in combination with neuroimaging markers in patients with different types of post-stroke cognitive impairment in acute ischemic stroke. Materials and Methods: In 72 patients we performed the assessment of cognitive status and distinguished 3 types: normal cognition, dysexecutive, and mixed cognitive impairment. In each group we determined the concentration of cytokines (IL-1ß, IL-6, TNFα, IL-10) in liquor and serum, ß-amyloid 1−40 in liquor and a number of MRI morphometric parameters and fractional anisotropy. Results: In all groups of patients we detected higher level of IL-10 in serum compared with the control. Patients with dysexecutive cognitive impairment had higher concentration of IL-1ß, IL-10 in liquor, IL-6 level in serum, lower fractional anisotropy of ipsilateral thalamus compared with patients with normal cognition and largest size of infarct. Patients with dysexecutive and mixed cognitive impairment had the higher area of leukoareosis and ventricular volume, reduced fractional anisotropy of contralateral cingulum compared with patients with normal cognition. Patients with mixed cognitive impairment characterized by lower fractional anisotropy of contralateral fronto-occipital fasciculus compared with patients with dysexecutive cognitive deficit. Conclusions: Serum and cerebrospinal fluid concentrations of cytokines studied in combination with MRI parameters particularly fractional anisotropy seems to be informative biomarkers of pathogenic types of PSCI.
[Mh] Termos MeSH primário: Isquemia Encefálica
Disfunção Cognitiva
Neuroimagem/métodos
Acidente Vascular Cerebral/complicações
[Mh] Termos MeSH secundário: Idoso
Anisotropia
Biomarcadores
Isquemia Encefálica/sangue
Isquemia Encefálica/fisiopatologia
Cognição/fisiologia
Disfunção Cognitiva/sangue
Disfunção Cognitiva/diagnóstico
Disfunção Cognitiva/etiologia
Disfunção Cognitiva/psicologia
Feminino
Seres Humanos
Interleucina-10/sangue
Interleucina-6/sangue
Masculino
Meia-Idade
Testes Neuropsicológicos
Estudos Prospectivos
Federação Russa
Estatística como Assunto
Fator de Necrose Tumoral alfa/sangue
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Biomarkers); 0 (Interleukin-6); 0 (Tumor Necrosis Factor-alpha); 130068-27-8 (Interleukin-10)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180208
[Lr] Data última revisão:
180208
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:180104
[St] Status:MEDLINE
[do] DOI:10.15690/vramn685


  8 / 11210 MEDLINE  
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[PMID]:27771736
[Au] Autor:Wang J; Ishimoto T; Nakano T
[Ad] Endereço:School of Material Science and Engineering, Zhengzhou University, Zhengzhou, 450001, China.
[Ti] Título:Unloading-Induced Degradation of the Anisotropic Arrangement of Collagen/Apatite in Rat Femurs.
[So] Source:Calcif Tissue Int;100(1):87-94, 2017 Jan.
[Is] ISSN:1432-0827
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The specific orientation of collagen and biological apatite (BAp) is an anisotropic feature of bone micro-organization; it is an important determinant of bone mechanical function and performance under anisotropic stress. However, it is poorly understood how this microstructure orientation is altered when the mechanical environment changes. We hypothesized that the preferential orientation of collagen/BAp would change in response to changes in mechanical conditions, similar to the manner in which bone mass and bone shape change. In the present study, we investigated the effect of unloading (removal of anisotropic stress) on the preferential orientation of collagen/BAp using a rat sciatic neurectomy model. Bone tissue that formed under unloaded conditions showed a more disordered collagen/BAp orientation than bone tissue that formed under physiological conditions. Coincidentally, osteocytes in unloaded bone displayed spherical morphology and random alignment. To the best of our knowledge, this study is the first to demonstrate the degradation of preferential collagen/BAp orientation in response to unloading conditions. In summary, we identified alterations in bone material anisotropy as an important aspect of the bone's response to unloading, which had previously been examined with regard to bone loss only.
[Mh] Termos MeSH primário: Apatitas/metabolismo
Colágeno/metabolismo
Fêmur/metabolismo
Osteócitos/metabolismo
[Mh] Termos MeSH secundário: Animais
Anisotropia
Densidade Óssea/fisiologia
Doenças Ósseas Metabólicas/metabolismo
Osso e Ossos/metabolismo
Ratos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Apatites); 9007-34-5 (Collagen)
[Em] Mês de entrada:1802
[Cu] Atualização por classe:180201
[Lr] Data última revisão:
180201
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161025
[St] Status:MEDLINE
[do] DOI:10.1007/s00223-016-0200-0


  9 / 11210 MEDLINE  
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[PMID]:28454907
[Au] Autor:Ruiz de Galarreta S; Antón R; Cazón A; Finol EA
[Ad] Endereço:Department of Mechanical Engineering, Tecnun, University of Navarra, Paseo Manuel de Lardizabal, 13, 20018 San Sebastián, Spain.
[Ti] Título:A methodology for developing anisotropic AAA phantoms via additive manufacturing.
[So] Source:J Biomech;57:161-166, 2017 05 24.
[Is] ISSN:1873-2380
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:An Abdominal Aortic Aneurysm (AAA) is a permanent focal dilatation of the abdominal aorta at least 1.5 times its normal diameter. The criterion of maximum diameter is still used in clinical practice, although numerical studies have demonstrated the importance of biomechanical factors for rupture risk assessment. AAA phantoms could be used for experimental validation of the numerical studies and for pre-intervention testing of endovascular grafts. We have applied multi-material 3D printing technology to manufacture idealized AAA phantoms with anisotropic mechanical behavior. Different composites were fabricated and the phantom specimens were characterized by biaxial tensile tests while using a constitutive model to fit the experimental data. One composite was chosen to manufacture the phantom based on having the same mechanical properties as those reported in the literature for human AAA tissue; the strain energy and anisotropic index were compared to make this choice. The materials for the matrix and fibers of the selected composite are, respectively, the digital materials FLX9940 and FLX9960 developed by Stratasys. The fiber proportion for the composite is equal to 0.15. The differences between the composite behavior and the AAA tissue are small, with a small difference in the strain energy (0.4%) and a maximum difference of 12.4% in the peak Green strain ratio. This work represents a step forward in the application of 3D printing technology for the manufacturing of AAA phantoms with anisotropic mechanical behavior.
[Mh] Termos MeSH primário: Aneurisma da Aorta Abdominal
Imagens de Fantasmas
[Mh] Termos MeSH secundário: Anisotropia
Aorta Abdominal
Ruptura Aórtica
Fenômenos Biomecânicos
Seres Humanos
Impressão Tridimensional
Medição de Risco
Estresse Mecânico
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1710
[Cu] Atualização por classe:180120
[Lr] Data última revisão:
180120
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170430
[St] Status:MEDLINE


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[PMID]:27776262
[Au] Autor:Sterling NW; Du G; Lewis MM; Swavely S; Kong L; Styner M; Huang X
[Ad] Endereço:Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA, USA.
[Ti] Título:Cortical gray and subcortical white matter associations in Parkinson's disease.
[So] Source:Neurobiol Aging;49:100-108, 2017 Jan.
[Is] ISSN:1558-1497
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Cortical atrophy has been documented in both Parkinson's disease (PD) and healthy aging, but its relationship to changes in subcortical white matter is unknown. This was investigated by obtaining T1- and diffusion-weighted images from 76 PD and 70 controls at baseline and 18 and 36 months, from which cortical volumes and underlying subcortical white matter axial diffusivity (AD), radial diffusivity (RD), and fractional anisotropy (FA) were determined. Twelve of 69 cortical subregions had significant group differences, and for these, underlying subcortical white matter was explored. At baseline, higher cortical volumes were significantly correlated with lower underlying subcortical white matter AD, RD, and higher FA (ps ≤ 0.017) in PD. Longitudinally, higher rates of cortical atrophy in PD were associated with increased rates of change in AD RD, and FA values (ps ≤ 0.0013) in 2 subregions explored. The significant gray-white matter associations were not found in controls. Thus, unlike healthy aging, cortical atrophy and subcortical white matter changes may not be independent events in PD.
[Mh] Termos MeSH primário: Córtex Cerebral/patologia
Substância Cinzenta/patologia
Doença de Parkinson/patologia
Substância Branca/patologia
[Mh] Termos MeSH secundário: Idoso
Anisotropia
Atrofia
Córtex Cerebral/diagnóstico por imagem
Imagem de Difusão por Ressonância Magnética
Imagem de Tensor de Difusão
Feminino
Substância Cinzenta/diagnóstico por imagem
Seres Humanos
Masculino
Meia-Idade
Bainha de Mielina
Neuroimagem
Doença de Parkinson/diagnóstico por imagem
Substância Branca/diagnóstico por imagem
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1711
[Cu] Atualização por classe:180112
[Lr] Data última revisão:
180112
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161025
[St] Status:MEDLINE



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