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1.
Shanghai Kou Qiang Yi Xue ; 28(2): 201-203, 2019.
Artigo em Chinês | MEDLINE | ID: mdl-31384910

RESUMO

PURPOSE: To explore a safe, effective and functional surgical treatment for children of Pierre Robin sequence (PRS) with cleft palate. METHODS: Twelve children of PRS with cleft palate underwent mandibular distraction osteogenesis before cleft palate surgery in order to correct severe hypoxia. A modified palatoplasty was then performed, the palatal flaps on both sides were not elevated in the anterior portions to prevent soft palate backward moving, and the levator veli palatini was repositioned simultaneously. RESULTS: All children achieved velopharyngeal closure without dyspnea after follow-up of 10-12 months. CONCLUSIONS: Measures should be taken to avoid backward movement of the soft palate, which may result in dyspnea of children with PRS in palatoplasty.


Assuntos
Fissura Palatina , Osteogênese por Distração , Síndrome de Pierre Robin , Criança , Fissura Palatina/cirurgia , Humanos , Osteogênese por Distração/métodos , Palato Mole , Síndrome de Pierre Robin/cirurgia , Retalhos Cirúrgicos
2.
Front Neural Circuits ; 13: 33, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31133820

RESUMO

Parental migration has caused millions of children left behind, especially in China and India. Left-behind children (LBC) have a high risk of mental disorders and may present negative life outcomes in the future. However, little is known whether there are cerebral structural alterations in LBC in relative to those with parents. This study is to explore the effect of parental migration on brain maturation by comparing gray matter volume (GMV) and fractional anisotropy (FA) of LBC with well-matched non-LBC. Thirty-eight LBC (21 boys, age = 9.60 ± 1.8 years) and 30 non-LBC (19 boys, age = 10.00 ± 1.95 years) were recruited and underwent brain scans in 3.0 T MR. Intelligence quotient and other factors including family income, guardians' educational level and separation time were also acquired. GMV and FA were measured for each participant and compared between groups using 2-sample t-tests with atlas-based analysis. Compared to non-LBC, LBC exhibited greater GMV in emotional and cortico-striato-thalamo-cortical circuits, and altered FA in bilateral superior occipitofrontal fasciculi and right medial lemniscus (p < 0.05, Cohen's d > 0.89, corrected for false-discovery rate). Other factors including family income, guardians' educational level and separation time were not associated with these brain changes. Our study provides empirical evidence of altered brain structure in LBC compared to non-LBC, responsible for emotion regulation and processing, which may account for mental disorders and negative life outcome of LBC. Our study suggests that absence of direct biological parental care may impact children's brain development. Therefore, public health efforts may be needed to provide additional academic and social/emotional supports to LBC when their parents migrate to seeking better economic circumstances, which has become increasingly common in developing countries.

3.
Neuroreport ; 30(7): 516-521, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30913134

RESUMO

Follow-up observation is needed for type 1 diabetes mellitus (T1DM) children due to the potential injury to the brain. However, the effect of short-term T1DM on gray matter in school-aged children is still unclear. This study aimed to evaluate gray matter volume (GMV) changes and their relationships with clinical variables in school-aged children with short-term T1DM. Twenty-one school-aged T1DM children were compared with 21 control patients, matched for sex and age. T1-weighted gradient echo three-dimensional MRI was performed using a 3.0-Tesla scanner and the resulting images were processed with FSL software to assess the difference in GMV between the two groups. The children with T1DM presented with decreased GMV in the left middle temporal gyrus (LMTG), the right postcentral gyrus, and the left triangular part of the frontal inferior gyrus (LTP-FIG). No significant changes in intelligence quotient (IQ) were found between the T1DM and control groups. In T1DM patients, there was a significant positive correlation between the GMV of LMTG and full-scale IQ or linguistic IQ. In addition, an increased glycosylated hemoglobin level was negatively correlated with reduced GMV in the LMTG and LTP-FIG in the T1DM group. These findings suggest that short-term T1DM could lead to regional structural brain deficits in school-aged children. The GMV of the LMTG may affect IQ, and poor recent glycemic control may have an adverse effect on GMV in the LMTG and LTP-FIG in T1DM children.Video abstract: http://links.lww.com/WNR/A506.

4.
Psychoneuroendocrinology ; 103: 67-75, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30658340

RESUMO

PURPOSE: The aim of the present study was to investigate the differences in the topological organization of functional brain networks between children with growth hormone deficiency (GHD) and those with idiopathic short stature (ISS). METHODS: Thirty-one children with GHD and fifty-three children with ISS were recruited based on the results of GH stimulation tests. Resting-state fMRI data were acquired from all children. Whole brain functional connectivity density (FCD) analysis and subsequent seed-based functional connectivity analysis were used to explore the differences in functional brain networks between the children with ISS and GHD. Correlation analyses among the results of clinical laboratory examinations, neuropsychological scales and FCD values of different brain regions were applied. RESULTS: Compared with the ISS group, the GHD group exhibited significantly decreased FCDs in the left postcentral gyrus, right precentral gyrus and left cerebellar lobules 7b and 6. The subsequent functional connectivity analysis found decreased functional connectivity between lobules 7b and 6 of the left cerebellum as well as the left postcentral gyrus and right precentral gyrus in the GHD group compared to that in the ISS group. In addition, the FCD values of region 6 of the left cerebellum in the GHD group were negatively correlated with the scores on the Symptom Checklist-90 and Eysenck Personality Questionnaire. The FCD value of the left postcentral gyrus in children with ISS positively correlated with IGFBP-3 levels and was approximately correlated with IGF-1 levels. CONCLUSIONS: These findings highlight the impact of growth hormone deficiency on the brain network that mainly involves the somatosensory, somatic motor and cerebellum networks, which may contribute to the behavioural problems observed in these children.

5.
J Craniofac Surg ; 29(6): e542-e543, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29543682

RESUMO

Bifid nose, an indicator of Tessier No.0, is a rare congenital malformation. Because of its rarity, few cases were reported and the optimal surgical procedure and the best time for surgery have not been widely acknowledged. In this brief report, a 9-year-old girl with mild bifid nose and unilateral mini-microform cleft lip, and its surgical management, is presented. We focused our attention on modifying the shape of the nose through open rhinoplasty without excising the surplus skin on the nasal dorsum and achieved good results.

6.
Nat Commun ; 8: 14364, 2017 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-28232668

RESUMO

Non-syndromic cleft lip with palate (NSCLP) is the most serious sub-phenotype of non-syndromic orofacial clefts (NSOFC), which are the most common craniofacial birth defects in humans. Here we conduct a GWAS of NSCLP with multiple independent replications, totalling 7,404 NSOFC cases and 16,059 controls from several ethnicities, to identify new NSCLP risk loci, and explore the genetic heterogeneity between sub-phenotypes of NSOFC. We identify 41 SNPs within 26 loci that achieve genome-wide significance, 14 of which are novel (RAD54B, TMEM19, KRT18, WNT9B, GSC/DICER1, PTCH1, RPS26, OFCC1/TFAP2A, TAF1B, FGF10, MSX1, LINC00640, FGFR1 and SPRY1). These 26 loci collectively account for 10.94% of the heritability for NSCLP in Chinese population. We find evidence of genetic heterogeneity between the sub-phenotypes of NSOFC and among different populations. This study substantially increases the number of genetic susceptibility loci for NSCLP and provides important insights into the genetic aetiology of this common craniofacial malformation.


Assuntos
Fenda Labial/genética , Fissura Palatina/genética , Loci Gênicos/genética , Predisposição Genética para Doença , Adulto , Fatores Etários , Grupo com Ancestrais do Continente Asiático/etnologia , Grupo com Ancestrais do Continente Asiático/genética , Estudos de Casos e Controles , Fenda Labial/etnologia , Fissura Palatina/etnologia , Estudos de Coortes , Feminino , Estudo de Associação Genômica Ampla , Técnicas de Genotipagem , Humanos , Masculino , Polimorfismo de Nucleotídeo Único , Fatores Sexuais
7.
Neural Plast ; 2017: 5167973, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28191353

RESUMO

Follow-up observation is required for mild-to-moderate hydrocephalic patients because of the potential damage to brain. However, effects of mild-to-moderate hydrocephalus on gray and white matter remain unclear in vivo. Using structural MRI and diffusion tensor imaging (DTI), current study compared the cortical thickness and white matter integrity between children with mild-to-moderate communicating hydrocephalus and healthy controls. The relationships between cortical changes and intelligence quota were also examined in patients. We found that cortical thickness in the left middle temporal and left rostral middle frontal gyrus was significantly lower in the hydrocephalus group compared with that of controls. Fractional anisotropy in the right corpus callosum body was significantly lower in the hydrocephalus group compared with that of controls. In addition, there was no association of cortical thinning or white matter fractional anisotropy with intelligence quota in either group. Thus, our findings provide clues to that mild-to-moderate hydrocephalus could lead to structural brain deficits especially in the middle temporal and middle frontal gyrus prior to the behavior changes.


Assuntos
Córtex Cerebral/patologia , Hidrocefalia/patologia , Substância Branca/patologia , Córtex Cerebral/diagnóstico por imagem , Criança , Imagem de Tensor de Difusão , Feminino , Humanos , Hidrocefalia/diagnóstico por imagem , Hidrocefalia/psicologia , Inteligência , Imagem por Ressonância Magnética , Masculino , Córtex Pré-Frontal/diagnóstico por imagem , Córtex Pré-Frontal/patologia , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/patologia , Substância Branca/diagnóstico por imagem
8.
Med Dosim ; 42(1): 47-52, 2017 Spring.
Artigo em Inglês | MEDLINE | ID: mdl-28126472

RESUMO

To evaluate the lung sparing in intensity-modulated radiation therapy (IMRT) for patients with upper thoracic esophageal tumors extending inferiorly to the thorax by different beam arrangement. Overall, 15 patient cases with cancer of upper thoracic esophagus were selected for a retrospective treatment-planning study. Intensity-modulated radiation therapy plans using 4, 5, and 7 beams (4B, 5B, and 7B) were developed for each patient by direct machine parameter optimization (DMPO). All plans were evaluated with respect to dose volumes to irradiated targets and normal structures, with statistical comparisons made between 4B with 5B and 7B intensity-modulated radiation therapy plans. Differences among plans were evaluated using a two-tailed Friedman test at a statistical significance of p < 0.05. The maximum dose, average dose, and the conformity index (CI) of planning target volume 1 (PTV1) were similar for 3 plans for each case. No significant difference of coverage for planning target volume 1 and maximum dose for spinal cords were observed among 3 plans in present study (p > 0.05). The average V5, V13, V20, mean lung dose, and generalized equivalent uniform dose (gEUD) for the total lung were significantly lower in 4B-plans than those data in 5B-plans and 7B-plans (p < 0.01). Although the average V30 for the total lung were significantly higher in 4B-plans than those in 5B-plans and 7B-plans (p < 0.05). In addition, when comparing with the 4B-plans, the conformity/heterogeneity index of the 5B- and 7B-plans were significantly superior (p < 0.05). The 4B-intensity-modulated radiation therapy plan has advantage to address the specialized problem of lung sparing to low- and intermediate-dose exposure in the thorax when dealing with relative long tumors extended inferiorly to the thoracic esophagus for upper esophageal carcinoma with the cost for less conformity. Studies are needed to compare the superiority of volumetric modulated arc therapy with intensity-modulated radiation therapy technique.


Assuntos
Carcinoma/radioterapia , Neoplasias Esofágicas/radioterapia , Planejamento da Radioterapia Assistida por Computador , Radioterapia de Intensidade Modulada/métodos , Adulto , Feminino , Humanos , Pulmão , Masculino , Pessoa de Meia-Idade , Tratamentos com Preservação do Órgão , Órgãos em Risco , Estudos Retrospectivos
9.
Spine J ; 17(2): 230-235, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27664342

RESUMO

BACKGROUND CONTEXT: Accurately evaluating the extent of trunk imbalance in the coronal plane is significant for patients before and after treatment. We preliminarily practiced a new method, axis-line-angle technique (ALAT), for evaluating coronal trunk imbalance with excellent intra-observer and interobserver reliability. Radiologists and surgeons were encouraged to use this method in clinical practice. However, the optimal cutoff value of the ALAT for determination of the extent of coronal trunk imbalance has not been calculated up to now. PURPOSE: The purpose of this study was to identify the cutoff value of the ALAT that best predicts a positive measurement point to assess coronal balance or imbalance. STUDY DESIGN/SETTING: A retrospective study at a university affiliated hospital was carried out. PATIENT SAMPLE: A total of 130 patients with C7-central sacral vertical line (CSVL) >0 mm and aged 10-18 years were recruited in this study from September 2013 to December 2014. OUTCOME MEASURES: Data were analyzed to determine the optimal cutoff value of the ALAT measurement. METHODS: The C7-CSVL and ALAT measurements were conducted respectively twice on plain film within a 2-week interval by two radiologists. The optimal cutoff value of the ALAT was analyzed via receiver operating characteristic (ROC) curve. Comparison variables were performed with chi-square test between the C7-CSVL and ALAT measurements for evaluating trunk imbalance. Kappa agreement coefficient method was used to test the intra-observer and interobserver agreement of C7-CSVL and ALAT. RESULTS: The ROC curve area for the ALAT was 0.82 (95% confidence interval: 0.753-0.894, p<.001). The maximum Youden index was 0.51, and the corresponding cutoff point was 2.59°. No statistical difference was found between the C7-CSVL and ALAT measurements for evaluating trunk imbalance (p>.05). Intra-observer agreement values for the C7-CSVL measurements by observers 1 and 2 were 0.79 and 0.91 (p<.001), respectively, whereas intra-observer agreement values for the ALAT measurements were both 0.89 by observers 1 and 2 (p<.001). The interobserver agreement values for the first and second measurements with the C7-CSVL were 0.78 and 0.85 (p<.001), respectively, whereas the interobserver agreement values for the first and second measurements with the ALAT were 0.91 and 0.88 (p<.001), respectively. CONCLUSIONS: The newly developed ALAT provided an acceptable optimal cutoff value for evaluating trunk imbalance in the coronal plane with a high level of intra-observer and interobserver agreement, which suggests that the ALAT is suitable for clinical use.


Assuntos
Radiografia Torácica/métodos , Escoliose/diagnóstico por imagem , Tronco/diagnóstico por imagem , Adolescente , Criança , Feminino , Humanos , Masculino , Variações Dependentes do Observador , Curva ROC , Reprodutibilidade dos Testes , Estudos Retrospectivos
10.
Child Abuse Negl ; 62: 89-99, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27794245

RESUMO

Whether a lack of direct parental care affects brain function in children is an important question, particularly in developing countries where hundreds of millions of children are left behind when their parents migrate for economic or political reasons. In this study, we investigated changes in the topological architectures of brain functional networks in left-behind children (LBC). Resting-state functional magnetic resonance imaging data were obtained from 26 LBC and 21 children living within their nuclear family (non-LBC). LBC showed a significant increase in the normalized characteristic path length (λ), suggesting a decrease in efficiency in information access, and altered nodal centralities in the fronto-limbic regions and motor and sensory systems. Moreover, a decreased nodal degree and the nodal betweenness of the right rectus gyrus were positively correlated with annual family income. The present study provides the first empirical evidence that suggests that a lack of direct parental care could affect brain functional development in children, particularly involving emotional networks.


Assuntos
Mapeamento Encefálico , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Criança Abandonada/psicologia , Emigrantes e Imigrantes , Imagem por Ressonância Magnética , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiopatologia , Adolescente , Criança , China , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Renda , Imagem por Ressonância Magnética/métodos , Masculino , Psicometria , Valores de Referência , Estatística como Assunto , Escalas de Wechsler/estatística & dados numéricos
11.
Zhonghua Yi Xue Za Zhi ; 95(23): 1846-8, 2015 Jun 16.
Artigo em Chinês | MEDLINE | ID: mdl-26712404

RESUMO

OBJECTIVE: To investigate the value of three-dimentional pseudo-continuous arterial spin labeling (ASL) perfusion imaging in differentiating acute cerebral infarction from acute encephalitis. METHODS: From September 2013 to September 2014, 42 patients with actue stroke onset and 20 healthy volunteers underwent conventional brain MRI DWI and 3D-ASL Perfusion Imaging in our hospital. Only 20 patients whose lesions located in the middle cerebral artery (MCA) territory were enrolled in this study. Of these cases, 12 cases were diagnosed with acute cerebral infarction, 8 were diagnosed with encephalitis. First, we analyzed the imaging features of the 20 patients and 20 volunteers. Then, CBF values of the lesions in the 20 patients and the gray matter of MCA territory in the 20 volunteers were measured on 3D-pcASL images. Third, the difference of mean CBF values between patients and volunteers were analyzed. RESULTS: Out of 20 study group, 19 patients whose lesions presented high signal intensity on DWI images, 12 cases were acute cerebral infarction and 8 were encephalitis. All the lesions of 20 cases showed abnormal perfusion on 3D-pcASL images. 3D-pcASL has good consistency with DWI in diagnostic capabilities (χ² = 0.565, P = 0.01). On 3D-pcASL, 11 acute cerebral infarction patients presented perfusion defects or low perfusion, 1 acute cerebral infarction patients showed high perfusion, 8 encephalitis patients showed inhomogeneous perfusion. The mean value of CBF was (17 ± 6) ml · min⁻¹ · 100 g⁻¹ in 12 acute cerebral infarction patients, (136 ± 69) ml · min⁻¹ · 100 g⁻¹ in 8 encephalitis patients and (68 ± 12) ml · min⁻¹ · 100 g⁻¹ three in 20 healthy volunteers. The difference in mean value of CBF among the three groups was statistically significant (P < 0.01). CONCLUSION: Acute cerebral infarction often shows low perfusion and acute encephalitis shows high perfusion on 3D-pcASL images, which has a higher application value in diagnosis and differentiation of acute cerebral infarction and encephalitis.


Assuntos
Isquemia Encefálica , Encefalite , Encéfalo , Infarto Cerebral , Humanos , Imagem Tridimensional , Angiografia por Ressonância Magnética , Artéria Cerebral Média , Perfusão , Marcadores de Spin , Acidente Vascular Cerebral
12.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 31(3): 703-7, 2014 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-25219261

RESUMO

The link between micro- and macro-parameters for radiation interactions that take place in living biological systems is described in this paper. Meanwhile recent progress and development in microdosimetry and nanodosimetry are introduced, including the methods to measure and calculate these micro- or nano-parameters. The relationship between radiobiology and physical quantities in microdosimetry and nanodosimetry was presented. Both the current problems on their applications in radiation protection and radiotherapy and the future development direction are proposed.


Assuntos
Radiobiologia , Radiometria , Humanos , Física , Proteção Radiológica
13.
PLoS One ; 9(3): e93432, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24676455

RESUMO

BACKGROUND: The core domains of social anxiety disorder (SAD), generalized anxiety disorder (GAD), panic disorder (PD) with and without agoraphobia (GA), and specific phobia (SP) are cognitive and physical symptoms that are related to the experience of fear and anxiety. It remains unclear whether these highly comorbid conditions that constitute the anxiety disorder subgroups of the Diagnostic and Statistical Manual for Mental Disorders--Fifth Edition (DSM-5) represent distinct disorders or alternative presentations of a single underlying pathology. METHODS: A systematic search of voxel-based morphometry (VBM) studies of SAD, GAD, PD, GA, and SP was performed with an effect-size signed differential mapping (ES-SDM) meta-analysis to estimate the clusters of significant gray matter differences between patients and controls. RESULTS: Twenty-four studies were eligible for inclusion in the meta-analysis. Reductions in the right anterior cingulate gyrus and the left inferior frontal gyrus gray matter volumes (GMVs) were noted in patients with anxiety disorders when potential confounders, such as comorbid major depressive disorder (MDD), age, and antidepressant use were controlled for. We also demonstrated increased GMVs in the right dorsolateral prefrontal cortex (DLPFC) in comorbid depression-anxiety (CDA), drug-naïve and adult patients. Furthermore, we identified a reduced left middle temporal gyrus and right precentral gyrus in anxiety patients without comorbid MDD. CONCLUSION: Our findings indicate that a reduced volume of the right ventral anterior cingulate gyrus and left inferior frontal gyrus is common in anxiety disorders and is independent of comorbid depression, medication use, and age. This generic effect supports the notion that the four types of anxiety disorders have a clear degree of overlap that may reflect shared etiological mechanisms. The results are consistent with neuroanatomical DLPFC models of physiological responses, such as worry and fear, and the importance of the ventral anterior cingulate (ACC)/medial prefrontal cortex (mPFC) in mediating anxiety symptoms.


Assuntos
Agorafobia/patologia , Transtornos de Ansiedade/patologia , Transtorno Depressivo Maior/patologia , Substância Cinzenta/patologia , Giro do Cíngulo/patologia , Transtorno de Pânico/patologia , Córtex Pré-Frontal/patologia , Adolescente , Adulto , Agorafobia/tratamento farmacológico , Agorafobia/fisiopatologia , Transtornos de Ansiedade/tratamento farmacológico , Transtornos de Ansiedade/fisiopatologia , Mapeamento Encefálico , Transtorno Depressivo Maior/tratamento farmacológico , Transtorno Depressivo Maior/fisiopatologia , Manual Diagnóstico e Estatístico de Transtornos Mentais , Feminino , Substância Cinzenta/efeitos dos fármacos , Substância Cinzenta/fisiopatologia , Giro do Cíngulo/efeitos dos fármacos , Giro do Cíngulo/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Transtorno de Pânico/tratamento farmacológico , Transtorno de Pânico/fisiopatologia , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/fisiopatologia , Psicotrópicos/uso terapêutico
14.
Zhonghua Yi Xue Za Zhi ; 93(31): 2463-6, 2013 Aug 20.
Artigo em Chinês | MEDLINE | ID: mdl-24300265

RESUMO

OBJECTIVE: To analyze the relationship between gestational age and apparent diffusion coefficient (ADC) values in different regions of fetal brain from middle to late trimester. METHODS: DW images performed in 70 singleton non-sedated fetuses with questionably abnormal results on sonography and normal fetal MR imaging results were retrospectively reviewed. The median gestational age was 32.4 weeks (range, 24-38).With the formula of ADC = ln (S600/S0)/(B0-B600), the mean ADC values were obtained for fetal parietal white matter (WM), frontal WM, temporal WM, occipital WM, pons, cerebellum, basal ganglia and thalamus. The relationship of mean ADC values in different regions with gestational age was analyzed with linear regression. RESULTS: The mean ADC values were 1.77 ± 0.32 mm(2)/s (SD) in fetal parietal white matter (WM), 1.71 ± 0.32 mm(2)/s in occipital WM, 1.31 ± 0.18 mm(2)/s in thalamus, 1.34 ± 0.15 mm(2)/s in basal ganglia. And the mean ADC values in cerebellum, pons, frontal WM and temporal WM were 1.17 ± 0.16, 1.41 ± 0.18, 1.87 ± 0.18 and 1.74 ± 0.19 mm(2)/s respectively. A significant negative correlation between ADC values and gestational age was found for parietal WM, occipital WM, pons, cerebellum, basal ganglia and thalamus (P < 0.05). Frontal WM ADC (P > 0.05) and temporal WM ADC (P = 0.05) did not significantly change with gestational age whereas only a downward trend was present. The correlation coefficient (r) and coefficient of regression (b) were 0.420 and -0.045 in parietal WM; 0.470 and -0.052 in occipital WM; 0.370 and -0.027 in cerebellum; 0.027 and -0.020 in pons; 0.320 and -0.027 in thalamus; 0.300 and -0.021 in basal ganglia. The mean ADC values peaked in frontal WM and lowest in pons. The mean ADC values in white matter were higher than those in deep gray nuclei, cerebellum and pons.With the development of fetal brain,ADC values declined the fastest in cerebellum and occipital WM, followed by basal ganglia and thalamus. CONCLUSION: Regional differences in non-sedated fetal brain ADC values and their evolutions with gestational age are likely to reflect variations in brain maturation.


Assuntos
Encéfalo/embriologia , Imagem de Difusão por Ressonância Magnética/métodos , Idade Gestacional , Feminino , Humanos , Gravidez , Segundo Trimestre da Gravidez , Terceiro Trimestre da Gravidez
15.
J Colloid Interface Sci ; 368(1): 456-61, 2012 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-22169183

RESUMO

The mesoporous carbon supported cobalt catalyst (15%Co/MC) was found to be more active and selective to C(5)(+) than the traditionally activated carbon supported one (15%Co/AC) for the Fischer-Tropsch synthesis (FTS). The addition of small amount of K(2)O and ZrO(2) significantly affected the FTS behavior of 15%Co/MC. The addition of 1% K inhibited the FTS activity dramatically, while the addition of 3% Zr increased the FTS activity significantly. The addition of K(2)O decreased the surface acidity while increased the surface basicity of 15%Co/MC, resulting in the increased heat of adsorption of CO and substantially decreased heat of adsorption of H(2) on Co. In contrast, the addition of ZrO(2) increased the surface acidity and heat of adsorption of H(2) on Co. The FTS activity was found to be related to the ratio of heats for the adsorption of CO and H(2) on the catalysts 15%Co/MC, 15%Co-1%K/MC and 15%Co-3%Zr/MC. The highest FTS activity was obtained on the catalyst with the heat ratio of 1.2.

16.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 28(5): 932-5, 945, 2011 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-22097258

RESUMO

Dose calculation algorithms based on the Monte Carlo (MC) method are widely regarded as the most accurate tool available in radiotherapy. The MC simulation in radiotherapy has been split into two parts, the radiation source simulation and patient simulation. In this research, a virtual source for simulating the linear accelerator head was constructed with measurement-driven models. The dependence between the calculation accuracy and the specification of various parameters was studied by comparison between the measurement data and calculation results. It has been shown that the dose profile obtained by MC simulation can be consistent with measurement data, suggesting that the compound effect of primary photons and secondary photons are considered with appropriate parameter specification. The requirement of modeling for MC simulation can be met in clinical conditions.


Assuntos
Modelos Biológicos , Método de Monte Carlo , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Simulação por Computador , Humanos , Imagens de Fantasmas , Dosagem Radioterapêutica
17.
Inorg Chem ; 49(18): 8270-5, 2010 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-20718431

RESUMO

In an attempt to synthesize novel zirconium phosphate materials, a series of syntheses have been performed in a deep eutectic solvent (DES), composed of tetrapropylammonium bromide (TPABr) and oxalic acid. As a result, this DES does not act as a template provider in reaction probably owing to the steric effects of the longer chains of the TPA cation, and only the α-Zr(HPO(4))(2)·H(2)O (α-ZrP) phase has been achieved. However, after organic amine was added to the initial reaction mixture in a normal way, the additives did act as a template to induce the zirconium phosphate framework. For example, with 1,4-dimethylpiperazine as an additive, a novel layered compound, [C(6)H(16)N(2)](0.5)Zr(H(0.5)PO(4))(2)·H(2)O (denoted as ZrPO(4)-DES8) was obtained. Its structure was determined from single-crystal X-ray diffraction (XRD) data and consists of zirconium phosphate layers with the protonated 1,4-dimethylpiperazine and water molecules in between. Interestingly, the two layered materials as additives in a liquid lubricant exhibit excellent friction behavior with higher load-carrying and antiwear capacities in comparison to typical lubricant additives such as MoS(2) and graphite, increase the P(B) value of the base oil by 27.2% and 8.5%, and decrease the wear scar diameter of the base oil by 43% and 36%, respectively. Scanning electron microscopy, XRD, and energy-dispersive X-ray spectrometry are used to investigate the lubricant behavior of those materials.

18.
Radiat Oncol ; 5: 65, 2010 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-20633283

RESUMO

PURPOSE: To study the impacts of multileaf collimators (MLC) width [standard MLC width of 10 mm (sMLC) and micro-MLC width of 4 mm (mMLC)] in the intensity-modulated radiotherapy (IMRT) planning for the upper thoracic esophageal cancer (UTEC). METHODS AND MATERIALS: 10 patients with UTEC were retrospectively planned with the sMLC and the mMLC. The monitor unites (MUs) and dose volume histogram-based parameters [conformity index (CI) and homogeneous index (HI)] were compared between the IMRT plans with sMLC and with mMLC. RESULTS: The IMRT plans with the mMLC were more efficient (average MUs: 703.1 +/- 68.3) than plans with the sMLC (average MUs: 833.4 +/- 73.8) (p < 0.05). Also, compared to plans with the sMLC, the plans with the mMLC showed advantages in dose coverage of the planning gross tumor volume (Pgtv) (CI 0.706 +/- 0.056/HI 1.093 +/- 0.021) and the planning target volume (PTV) (CI 0.707 +/- 0.029/HI 1.315 +/- 0.013) (p < 0.05). In addition, the significant dose sparing in the D5 (3260.3 +/- 374.0 vs 3404.5 +/- 374.4)/gEUD (1815.1 +/- 281.7 vs 1849.2 +/- 297.6) of the spinal cord, the V10 (33.2 +/- 6.5 vs 34.0 +/- 6.7), V20 (16.0 +/- 4.6 vs 16.6 +/- 4.7), MLD (866.2 +/- 174.1 vs 887.9 +/- 172.1) and gEUD (938.6 +/- 175.2 vs 956.8 +/- 171.0) of the lungs were observed in the plans with the mMLC, respectively (p < 0.05). CONCLUSIONS: Comparing to the sMLC, the mMLC not only demonstrated higher efficiencies and more optimal target coverage, but also considerably improved the dose sparing of OARs in the IMRT planning for UTEC.


Assuntos
Neoplasias Esofágicas/radioterapia , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia de Intensidade Modulada/métodos , Humanos , Radiometria , Estudos Retrospectivos , Neoplasias Torácicas/patologia
19.
Radiother Oncol ; 96(1): 73-7, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20347496

RESUMO

BACKGROUND AND PURPOSE: To investigate the feasibility of using intravenous contrast-enhanced computed tomography (CT) scans in 3-dimensional conformal radiotherapy (3D-CRT), stereotactic body radiation therapy (SBRT) and intensity-modulated radiotherapy (IMRT) treatment planning for lung cancers, respectively. MATERIALS AND METHODS: Twelve patients with bulky lung tumors and 14 patients with small lung tumors were retrospectively analyzed. Each patient took two sets of CT in the same position with active breathing control (ABC) technique before and after intravenous contrast agent (CA) injections. Bulky tumors were planned with 3D-CRT, while SBRT plans were generated for patients with small tumors based on CT scans with intravenous CA. In addition, IMRT plans were generated for patients with bulky tumors to continue on a planning study. All plans were copied and replaced on the scans without intravenous CA. The radiation doses calculated from the two sets of CTs were compared with regard to planning volumes (PTV), the organ at-risk (OAR) and the lungs using Wilcoxon's signed rank test. RESULTS: In comparisons for 3D-CRT plans, CT scans with intravenous CA reduced the mean dose and the maximum dose of PTV with significant differences (p<0.05) that were within 1.0%. Comparing IMRT and SBRT plans, CT scans with intravenous CA obviously increased the minimum irradiation dose and dose of 95% volume of target received (D(95)) for targets, respectively (p<0.05). There was no statistical significance for lung parameters between two sets of scans in SBRT plans and IMRT plans. CONCLUSIONS: The enhanced CT scans can be used for both target delineation and treatment planning in 3D-CRT. The dose difference caused by intravenous CA is small. But for SBRT and IMRT, the minimum irradiation dose in targets may be estimated to be increased up to 2.71% while the maximum dose may be estimated to be decreased up to 1.36%. However, the difference in dose distribution in most cases were found to be clinical tolerable.


Assuntos
Meios de Contraste/administração & dosagem , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/radioterapia , Intensificação de Imagem Radiográfica/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Carcinoma de Pequenas Células do Pulmão/diagnóstico por imagem , Carcinoma de Pequenas Células do Pulmão/radioterapia , Adulto , Idoso , Estudos de Viabilidade , Feminino , Seguimentos , Humanos , Imagem Tridimensional/métodos , Injeções Intravenosas , Neoplasias Pulmonares/cirurgia , Masculino , Pessoa de Meia-Idade , Radiocirurgia/métodos , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos , Estudos Retrospectivos , Carcinoma de Pequenas Células do Pulmão/cirurgia , Tomografia Computadorizada por Raios X/métodos , Resultado do Tratamento
20.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 27(1): 193-7, 2010 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-20337052

RESUMO

Craniospinal radiation is one of essential components in the treatment flow for a number of central nervous system malignancies. Meticulous attention to technique and dosimetry is required to produce optimum tumor control. In this paper, an optimized treatment regimen was proposed based on multiple techniques. The CT images for a 17-year-old male patient in need of craniospinal radiation were acquired for 3D conformal treatment planning. The split-beam technique, the extended penumbra fields matching technique, and the multiple leaf collimator segments and extended SSD technique were synthesized in the treatment regimen so as to work out an optimized treatment plan. The added few segments improved the dose homogeneity in spinal cord. The maximal point dose was decreased from 124% to 108% of the prescribed dose in it. Comparative study on the anthropomorphic phantom showed that the data collected by thermoluminescent detectors and the data obtained by calculation were basically coincident. These results suggest that the proposed technique be clinically acceptable.


Assuntos
Neoplasias Encefálicas/radioterapia , Planejamento da Radioterapia Assistida por Computador , Radioterapia Conformacional/métodos , Neoplasias da Medula Espinal/radioterapia , Adolescente , Neoplasias Encefálicas/diagnóstico por imagem , Humanos , Imagem por Ressonância Magnética , Masculino , Neoplasias Embrionárias de Células Germinativas/radioterapia , Radiometria/métodos , Neoplasias da Medula Espinal/diagnóstico por imagem , Tomografia Computadorizada por Raios X
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